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Sample records for island biogeography revisited

  1. Island biogeography

    DEFF Research Database (Denmark)

    Whittaker, Robert James; Fernández-Palacios, José María; Matthews, Thomas J.

    2017-01-01

    Islands provide classic model biological systems. We review how growing appreciation of geoenvironmental dynamics of marine islands has led to advances in island biogeographic theory accommodating both evolutionary and ecological phenomena. Recognition of distinct island geodynamics permits gener...

  2. The general dynamic model of island biogeography revisited on the level of major plant families

    DEFF Research Database (Denmark)

    Lenzner, Bernd; Beierkuhnlein, Carl; Patrick, Weigelt

    2017-01-01

    Aim: The general dynamic model (GDM) proposed by Whittaker et al. (2008) is a widely accepted theoretical framework in island biogeography. In this study, we explore whether GDM predictions hold when overall plant diversity is deconstructed into major plant families. Location: 101 islands from 14...... oceanic archipelagos worldwide. Methods: Occurrence data for all species of nine large, cosmopolitan flowering plant families were used to test predictions derived from the GDM. We analyzed the effects of island area and age on species richness as well as number and percentage of single-island endemic...... species per family using mixed-effect models. Results: Total species and endemic richness as well as the percentage of endemic species showed a hump-shaped relationship with island age. The overall pattern was mainly driven by few species-rich plant families. Varying patterns were found for individual...

  3. Island biogeography of marine organisms

    Science.gov (United States)

    Pinheiro, Hudson T.; Bernardi, Giacomo; Simon, Thiony; Joyeux, Jean-Christophe; Macieira, Raphael M.; Gasparini, João Luiz; Rocha, Claudia; Rocha, Luiz A.

    2017-09-01

    Studies on the distribution and evolution of organisms on oceanic islands have advanced towards a dynamic perspective, where terrestrial endemicity results from island geographical aspects and geological history intertwined with sea-level fluctuations. Diversification on these islands may follow neutral models, decreasing over time as niches are filled, or disequilibrium states and progression rules, where richness and endemism rise with the age of the archipelago owing to the splitting of ancestral lineages (cladogenesis). However, marine organisms have received comparatively little scientific attention. Therefore, island and seamount evolutionary processes in the aquatic environment remain unclear. Here we analyse the evolutionary history of reef fishes that are endemic to a volcanic ridge of seamounts and islands to understand their relations to island evolution and sea-level fluctuations. We also test how this evolutionary history fits island biogeography theory. We found that most endemic species have evolved recently (Pleistocene epoch), during a period of recurrent sea-level changes and intermittent connectivity caused by repeated aerial exposure of seamounts, a finding that is consistent with an ephemeral ecological speciation process. Similar to findings for terrestrial biodiversity, our data suggest that the marine speciation rate on islands is negatively correlated with immigration rate. However, because marine species disperse better than terrestrial species, most niches are filled by immigration: speciation increases with the random accumulation of species with low dispersal ability, with few opportunities for in situ cladogenesis and adaptive radiation. Moreover, we confirm that sea-level fluctuations and seamount location play a critical role in marine evolution, mainly by intermittently providing stepping stones for island colonization.

  4. Equilibrium theory of island biogeography: A review

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    Angela D. Yu; Simon A. Lei

    2001-01-01

    The topography, climatic pattern, location, and origin of islands generate unique patterns of species distribution. The equilibrium theory of island biogeography creates a general framework in which the study of taxon distribution and broad island trends may be conducted. Critical components of the equilibrium theory include the species-area relationship, island-...

  5. Palaeo island-affinities revisited--biogeography and systematics of the Indo-Pacific genus Cethosia Fabricius (Lepidoptera: Nymphalidae).

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    Müller, C J; Beheregaray, L B

    2010-10-01

    The Indo-Pacific is a very complex region encompassing several micro-continents with unique tectonic and geomorphologic histories. Unsurprisingly, the biogeographic history of Indo-Pacific biota is generally poorly known, especially that of organisms found in the heart of the region, the biodiversity hotspot known as Wallacea. Here, we explore the biogeographic history of the Indo-Pacific butterfly genus Cethosia using all known species and many distinctive subspecies. Cethosia butterflies span the Indo-Pacific tropics, including several lineages with localized endemism that are critically important when reconstructing biogeographic history of the Indo-Pacific and, in particular, of Wallacea. A phylogenetic hypothesis is proposed, based on sequences of the mitochondrial genes cytochrome oxidase subunit I (COI) and NADH dehydrogenase 5 (ND5), and the nuclear wingless gene. Both Maximum Parsimony and Bayesian analyses showed that the genus is monophyletic and consistently recovered seven, generally very well supported, clades, namely the cydippe, leschenault, biblis, nietneri, hypsea, penthesilea and cyane clades. Species group relationships are largely concordant with general morphology (i.e., wing pattern and colouration) and, based on the phylogeny, we propose a revised systematic classification at the species level. The evolution of the genus appears associated with the inferred geological history of the region, in particular with respect to the expanding Wallacea theory, whereby ancient connected terranes were fragmented during the mid Miocene to early Pliocene, approximately 14-3 Mya. Recent diversification events in Cethosia were likely promoted by climatic fluctuations during the Pliocene and, to a lesser extent, the Pleistocene. Our results support the view that, while dispersal has been important for Cethosia throughout much of the region, the high levels of island endemism and the essentially allopatric radiations recovered in Cethosia in Wallacea are

  6. The reticulating phylogeny of island biogeography theory.

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    Lomolino, Mark V; Brown, James H

    2009-12-01

    Biogeographers study all patterns in the geographic variation of life, from the spatial variation in genetic and physiological characteristics of cells and individuals, to the diversity and dynamics of biological communities among continental biotas or across oceanic archipelagoes. The field of island biogeography, in particular, has provided some genuinely transformative insights for the biological sciences, especially ecology and evolutionary biology. Our purpose here is to review the historical development of island biogeography theory during the 20th century by identifying the common threads that run through four sets of contributions made during this period, including those by Eugene Gordon Munroe (1948, 1953), Edward O. Wilson (1959, 1961), Frank W. Preston (1962a,b), and the seminal collaborations between Wilson and Robert H. MacArthur (1963, 1967), which revolutionized the field and served as its paradigm for nearly four decades. This epistemological account not only reviews the intriguing history of island theory, but it also includes fundamental lessons for advancing science through transformative integrations. Indeed, as is likely the case with many disciplines, island theory advanced not as a simple accumulation of facts and an orderly succession of theories and paradigms, but rather in fits and starts through a reticulating phylogeny of ideas and alternating periods of specialization and reintegration. We conclude this review with a summary of the salient features of this scientific revolution in the contest of Kuhn's structure, which strongly influenced theoretical advances during this period, and we then describe some of the fundamental assumptions and tenets of an emerging reintegration of island biogeography theory.

  7. Three Mile Island revisited

    International Nuclear Information System (INIS)

    MacLeod, G.K.

    1986-01-01

    The accident at Three Mile Island proved that the Pennsylvania Department of Health lacked the tools to deal with the serious health consequences that occurred during and after this emergency. Despite the relative safety of nuclear power generation, we must be better prepared for the health and medical consequences of serous radiation emergencies. The author reviews the Three Mile Island accident through the eyes of newspaper reporters

  8. Biogeography

    Science.gov (United States)

    Quattrochi, Dale A.; Arnold, James E. (Technical Monitor)

    2002-01-01

    As a field of study, biogeography may be considered a bricolage - it has been constructed from many different facets from an array of research disciplines including biology, botany, zoology, geography, and geology. Biogeography focuses on the study of the constantly changing ranges of plants and animals, over multitude of space and time scales. It also includes the study of the structure and dynamics of biotic communities and ecosystems as they relate to both natural and anthropogenic processes. As it exists today, biogeography is an interdisciplinary research area founded in both the biological and Earth sciences. From a purely biological perspective, biogeography may be perceived as one of two types of studies: 1. biotic distributions and broad scales, and interpretations of the evolutionary and dispersal history of a single taxon or a few taxa; or 2. biotic distributions at local-to-regional scales, and interpretations of these distributions in relation to contemporary environments and rates of immigration or extinction. The first type of study is what is most usually associated with the term "biogeography" as disciplinary research field. It is conventionally termed "classical biogeography" because it reflects the continuity of research foci on which biogeography was founded in the nineteenth-century. The second type of biogeographical study has more modern day roots and is termed "geographical ecology" to reflect the theoretical predilections of ecologists and population biologists. Geographical ecology for all intents has become merged with ecology and exists as a sub discipline within this larger field of study.

  9. Models of oceanic island biogeography: changing perspectives on biodiversity dynamics in archipelagoes

    Directory of Open Access Journals (Sweden)

    Lawrence R Heaney

    2013-12-01

    Full Text Available Models of biogeographic processes can both enhance and inhibit our ability to ask questions that guide our understanding of patterns and processes. The two ‘traditional’ models of island biogeography, the Equilibrium Model and the Vicariance Model, raise important and insightful questions about relevant processes, but both fail to raise many crucial questions. An example involving the non-volant mammals of the Philippine archipelago shows that both models highlight some, but not all, relevant patterns and processes. The more recently proposed General Dynamic Model successfully combines many of the positive aspects of the two traditional models, but leaves some important questions unasked. We pose a number of questions here that may help guide further development of models of island biogeography.

  10. Pollination, biogeography and phylogeny of oceanic island bellflowers (Campanulaceae)

    DEFF Research Database (Denmark)

    Olesen, Jens Mogens; Alarcón, M.; Ehlers, Bodil

    2012-01-01

    relatives C. eminii and C. abyssinica. We asked to what extent related species converge in their floral biology and pollination in related habitats, i.e. oceanic islands. Study islands were the Azores, Madeira, Canary Islands, Cape Verde, Mauritius, and Réunion. Information about phylogenetic relationships....... These examples of vertebrate pollination evolved independently on each island or archipelago. We discuss if these pollination systems have an island or mainland origin and when they may have evolved, and finally, we attempt to reconstruct the pollinator-interaction history of each species....

  11. Pollination, biogeography and phylogeny of oceanic island bellflowers (Campanulaceae)

    DEFF Research Database (Denmark)

    Olesen, Jens Mogens; Alarcón, M.; Ehlers, Bodil

    2012-01-01

    . These examples of vertebrate pollination evolved independently on each island or archipelago. We discuss if these pollination systems have an island or mainland origin and when they may have evolved, and finally, we attempt to reconstruct the pollinator-interaction history of each species.......We studied the pollination biology of nine island Campanulaceae species: Azorina vidalii, Musschia aurea, M. wollastonii, Canarina canariensis, Campanula jacobaea, Nesocodon mauritianus, and three species of Heterochaenia. In addition, we compared C. canariensis to its two African mainland...... relatives C. eminii and C. abyssinica. We asked to what extent related species converge in their floral biology and pollination in related habitats, i.e. oceanic islands. Study islands were the Azores, Madeira, Canary Islands, Cape Verde, Mauritius, and Réunion. Information about phylogenetic relationships...

  12. Towards a glacial‐sensitive model of island biogeography

    NARCIS (Netherlands)

    Fernández-Palacios, J.M.; Rijsdijk, K.F.; Norder, S.J.; Otto, R.; de Nascimento, L.; Fernández‐Lugo, S.; Tjørve, E.; Whittaker, R.J.

    2016-01-01

    Although the role that Pleistocene glacial cycles have played in shaping the present biota of oceanic islands world-wide has long been recognized, their geographical, biogeographical and ecological implications have not yet been fully incorporated within existing biogeographical models. Here we

  13. Island biogeography and landscape structure: Integrating ecological concepts in a landscape perspective of anthropogenic impacts in temporary wetlands

    International Nuclear Information System (INIS)

    Angeler, David G.; Alvarez-Cobelas, Miguel

    2005-01-01

    Although our understanding of environmental risk assessment in temporary wetlands has been improved by the use of multi-species toxicity testing, we still know little of how landscape variables mediate the strength of, and recovery from, anthropogenic stress in such ecosystems. To bridge this research gap, we provide a theoretical framework of the response of temporary wetlands to anthropogenic disturbance along a habitat-isolation continuum based on island biogeography theory, landscape ecology and dispersal and colonization strategies of temporary wetland organisms. - Environmental risk assessment in temporary wetlands may benefit from consideration of island biogeography theory and landscape structure

  14. Introduction to the Arizona Sky Island Arthropod Project (ASAP): Systematics, biogeography, ecology, and population genetics of arthropods of the Madrean Sky Islands

    Science.gov (United States)

    Wendy Moore; Wallace M. Meyer; Jeffrey A. Eble; Kimberly Franklin; John F. Wiens; Richard C. Brusca

    2013-01-01

    The Arizona Sky Island Arthropod Project (ASAP) is a new multi-disciplinary research program at the University of Arizona that combines systematics, biogeography, ecology, and population genetics to study origins and patterns of arthropod diversity along elevation gradients and among mountain ranges in the Madrean Sky Island Region. Arthropods represent taxonomically...

  15. Revisiting the Metaphor of the Island: Challenging "World Culture" from an Island Misunderstood

    Science.gov (United States)

    Rappleye, Jeremy

    2015-01-01

    This article revisits the newly "discovered" island that world culture theorists have repeatedly utilised to explain their theoretical stance, conceptual preferences and methodological approach. Yet, it seeks to (re)connect world culture with the real world by replacing their imagined atoll with a real one--the island-nation of Japan. In…

  16. Extensions of Island Biogeography Theory predict the scaling of functional trait composition with habitat area and isolation.

    Science.gov (United States)

    Jacquet, Claire; Mouillot, David; Kulbicki, Michel; Gravel, Dominique

    2017-02-01

    The Theory of Island Biogeography (TIB) predicts how area and isolation influence species richness equilibrium on insular habitats. However, the TIB remains silent about functional trait composition and provides no information on the scaling of functional diversity with area, an observation that is now documented in many systems. To fill this gap, we develop a probabilistic approach to predict the distribution of a trait as a function of habitat area and isolation, extending the TIB beyond the traditional species-area relationship. We compare model predictions to the body-size distribution of piscivorous and herbivorous fishes found on tropical reefs worldwide. We find that small and isolated reefs have a higher proportion of large-sized species than large and connected reefs. We also find that knowledge of species body-size and trophic position improves the predictions of fish occupancy on tropical reefs, supporting both the allometric and trophic theory of island biogeography. The integration of functional ecology to island biogeography is broadly applicable to any functional traits and provides a general probabilistic approach to study the scaling of trait distribution with habitat area and isolation. © 2016 John Wiley & Sons Ltd/CNRS.

  17. Biogeography in Cellana (Patellogastropoda, Nacellidae with Special Emphasis on the Relationships of Southern Hemisphere Oceanic Island Species.

    Directory of Open Access Journals (Sweden)

    Claudio A González-Wevar

    Full Text Available Oceanic islands lacking connections to other land are extremely isolated from sources of potential colonists and have acquired their biota mainly through dispersal from geographically distant areas. Hence, isolated island biota constitutes interesting models to infer biogeographical mechanisms of dispersal, colonization, differentiation, and speciation. Limpets of the genus Cellana (Nacellidae: Patellogastropoda show limited dispersal capacity but are broadly distributed across the Indo-Pacific including many endemic species in isolated oceanic islands. Here, we examined main distributional patterns and geographic boundaries among Cellana lineages with special emphasis in the relationships of Southern Hemisphere oceanic islands species. Phylogenetic reconstructions based on mtDNA (COI recognized three main clades in Cellana including taxa from different provinces of the Indo-Pacific. Clear genetic discontinuities characterize the biogeography of Cellana and several lineages are associated to particular areas of the Indo-Pacific supporting the low dispersal capacity of the genus across recognized biogeographical barriers in the region. However, evolutionary relationships within Cellana suggest that long-distance dispersal processes have been common in the history of the genus and probably associated to the origin of the species in Hawaii and Juan Fernández Archipelago. Therefore, the presence of Cellana species in geographically distant Southern Hemisphere oceanic islands, such as the Juan Fernández Archipelago, suggests that long-distance dispersal mediated by rafting may have played an important role in the biogeography of the genus.

  18. Biogeography in Cellana (Patellogastropoda, Nacellidae) with Special Emphasis on the Relationships of Southern Hemisphere Oceanic Island Species

    Science.gov (United States)

    Nakano, Tomoyuki; Palma, Alvaro; Poulin, Elie

    2017-01-01

    Oceanic islands lacking connections to other land are extremely isolated from sources of potential colonists and have acquired their biota mainly through dispersal from geographically distant areas. Hence, isolated island biota constitutes interesting models to infer biogeographical mechanisms of dispersal, colonization, differentiation, and speciation. Limpets of the genus Cellana (Nacellidae: Patellogastropoda) show limited dispersal capacity but are broadly distributed across the Indo-Pacific including many endemic species in isolated oceanic islands. Here, we examined main distributional patterns and geographic boundaries among Cellana lineages with special emphasis in the relationships of Southern Hemisphere oceanic islands species. Phylogenetic reconstructions based on mtDNA (COI) recognized three main clades in Cellana including taxa from different provinces of the Indo-Pacific. Clear genetic discontinuities characterize the biogeography of Cellana and several lineages are associated to particular areas of the Indo-Pacific supporting the low dispersal capacity of the genus across recognized biogeographical barriers in the region. However, evolutionary relationships within Cellana suggest that long-distance dispersal processes have been common in the history of the genus and probably associated to the origin of the species in Hawaii and Juan Fernández Archipelago. Therefore, the presence of Cellana species in geographically distant Southern Hemisphere oceanic islands, such as the Juan Fernández Archipelago, suggests that long-distance dispersal mediated by rafting may have played an important role in the biogeography of the genus. PMID:28099466

  19. The effects of biogeography on ant diversity and activity on the Boston Harbor Islands, Massachusetts, U.S.A.

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    Clark, Adam T; Rykken, Jessica J; Farrell, Brian D

    2011-01-01

    Many studies have examined how island biogeography affects diversity on the scale of island systems. In this study, we address how diversity varies over very short periods of time on individual islands. To do this, we compile an inventory of the ants living in the Boston Harbor Islands National Recreation Area, Boston, Massachusetts, USA using data from a five-year All Taxa Biodiversity Inventory of the region's arthropods. Consistent with the classical theory of island biogeography, species richness increased with island size, decreased with island isolation, and remained relatively constant over time. Additionally, our inventory finds that almost half of the known Massachusetts ant fauna can be collected in the BHI, and identifies four new species records for Massachusetts, including one new to the United States, Myrmica scabrinodis. We find that the number of species actually active on islands depended greatly on the timescale under consideration. The species that could be detected during any given week of sampling could by no means account for total island species richness, even when correcting for sampling effort. Though we consistently collected the same number of species over any given week of sampling, the identities of those species varied greatly between weeks. This variation does not result from local immigration and extinction of species, nor from seasonally-driven changes in the abundance of individual species, but rather from weekly changes in the distribution and activity of foraging ants. This variation can be upwards of 50% of ant species per week. This suggests that numerous ant species on the BHI share the same physical space at different times. This temporal partitioning could well explain such unexpectedly high ant diversity in an isolated, urban site.

  20. The effects of biogeography on ant diversity and activity on the Boston Harbor Islands, Massachusetts, U.S.A.

    Directory of Open Access Journals (Sweden)

    Adam T Clark

    Full Text Available Many studies have examined how island biogeography affects diversity on the scale of island systems. In this study, we address how diversity varies over very short periods of time on individual islands. To do this, we compile an inventory of the ants living in the Boston Harbor Islands National Recreation Area, Boston, Massachusetts, USA using data from a five-year All Taxa Biodiversity Inventory of the region's arthropods. Consistent with the classical theory of island biogeography, species richness increased with island size, decreased with island isolation, and remained relatively constant over time. Additionally, our inventory finds that almost half of the known Massachusetts ant fauna can be collected in the BHI, and identifies four new species records for Massachusetts, including one new to the United States, Myrmica scabrinodis. We find that the number of species actually active on islands depended greatly on the timescale under consideration. The species that could be detected during any given week of sampling could by no means account for total island species richness, even when correcting for sampling effort. Though we consistently collected the same number of species over any given week of sampling, the identities of those species varied greatly between weeks. This variation does not result from local immigration and extinction of species, nor from seasonally-driven changes in the abundance of individual species, but rather from weekly changes in the distribution and activity of foraging ants. This variation can be upwards of 50% of ant species per week. This suggests that numerous ant species on the BHI share the same physical space at different times. This temporal partitioning could well explain such unexpectedly high ant diversity in an isolated, urban site.

  1. An attempt to revisit the global biogeography of limno-terrestrial Tardigrada

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    Philip J.A. PUGH

    2007-09-01

    Full Text Available The major increase in distribution records of limno-terrestrial tardigrades over the last ten years has enabled us to reassess the global biogeography of the Tardigrada using cluster analysis, principal components analysis and parsimony analysis of endemism (PAE. Although the new clustergram topology shows a close correlation with those we originally presented in 1998, the PAE outputs warrant a radical reinterpretation of the results as they imply that the Laurasian fauna is derived and the Gondwanan groups basal. The distribution of endemic tardigrade genera and families provides some support for this argument though the findings should be viewed with some caution as PAE has its detractors and has not been previously applied on a 'global' scale.

  2. Introduction to the Arizona Sky Island Arthropod Project (ASAP): Systematics, Biogeography, Ecology, and Population Genetics of Arthropods of the Madrean Sky Islands.

    Science.gov (United States)

    Moore, Wendy; Meyer, Wallace M; Eble, Jeffrey A; Franklin, Kimberly; Wiens, John F; Brusca, Richard C

    2013-01-01

    The Arizona Sky Island Arthropod Project (ASAP) is a new multi-disciplinary research program at the University of Arizona that combines systematics, biogeography, ecology, and population genetics to study origins and patterns of arthropod diversity along elevation gradients and among mountain ranges in the Madrean Sky Island Region. Arthropods represent taxonomically and ecologically diverse organisms that drive key ecosystem processes in this mountain archipelago. Using data from museum specimens and specimens we obtain during long-term collecting and monitoring programs, ASAP will document arthropod species across Arizona's Sky Islands to address a number of fundamental questions about arthropods of this region. Baseline data will be used to determine climatic boundaries for target species, which will then be integrated with climatological models to predict future changes in arthropod communities and distributions in the wake of rapid climate change. ASAP also makes use of the natural laboratory provided by the Sky Islands to investigate ecological and genetic factors that influence diversification and patterns of community assembly. Here, we introduce the project, outline overarching goals, and describe preliminary data from the first year of sampling ground-dwelling beetles and ants in the Santa Catalina Mountains.

  3. Oceanic island biogeography through the lens of the general dynamic model

    DEFF Research Database (Denmark)

    Borregaard, Michael K.; Amorim, Isabel R.; Borges, Paulo A. V.

    2017-01-01

    and in developing and enhancing ecological-evolutionary understanding of oceanic island systems through the lens of the GDM. In particular, we focus on four main themes: (i) macroecological tests using a space-for-time rationale; (ii) extensions of theory to islands following different patterns of ontogeny; (iii...

  4. Speciose opportunistic nectar-feeding avifauna in Cuba and its association to hummingbird island biogeography

    DEFF Research Database (Denmark)

    Dalsgaard, Bo; Baquero, Andrea C.; Rahbek, Carsten

    2016-01-01

    Island organisms often have wider feeding niches than mainland organisms, and migratory birds breeding on continents often widen their niches when overwintering on islands. Cuba's low hummingbird richness has puzzled ornithologists for decades. Here, we show that the Cuban hummingbird fauna is less...... rich than expected based on Cuba's elevation, when compared to the rest of the West Indian islands. Thereafter, we report nectar-feeding behaviour by 26 non-Trochilidae bird species in Cuba, encompassing pigeons/doves, woodpeckers and passerines, and endemic, resident and migratory species. We discuss...

  5. Revisited Inventory of Glaciers on Axel Heiberg Island, Nunavut

    Science.gov (United States)

    Thomson, L.; Osinski, G.

    2009-05-01

    As documented in the IPCC's Climate Change 2007 report, the high latitude regions of the Northern Hemisphere are experiencing the highest rates of warming. Given that 35% of the global glacial ice exists within the Arctic Archipelago, this region provides an excellent laboratory for monitoring the anticipated degree of glacial recession [1]. Evidence of arctic warming through negative mass balance trends has been detected in several studies already [e.g., 2]. Here, we show the importance and value of historical records in the task of monitoring glacial retreat. A highly detailed inventory developed by S. Ommanney in 1969 [3], has been revisited and transformed into digital format for the purposes of integration with modern inventories. The Ommanney inventory covers the entirety of Axel Heiberg Island , NU, and includes details often lacking in present day inventories, including orientations (accumulation and ablation zones), elevations (highest, lowest, elevation of the snowline, and the mean elevations of both the accumulation and ablation areas), length (of the ablation area, exposed ice, and of the total glacier including debris cover), area (of the ablation area, exposed ice, and of the total glacier), accumulation area ratio (AAR), depth, volume, and a six digit code which gives qualitative details on glacier attributes. This report is one of the most thorough and comprehensive glacier inventory report ever published in Canada. More recent inventories used for comparison include the glacier extents created by the National Topographic System based on photography from 1980-1987, as well as extents developed by Dr. Luke Copland for the Global Land Ice Measurements from Space (GLIMS) database using 1999-2000 satellite imagery. Our preliminary results show that approximately 90% of ice bodies under 0.2km on Axel Heiberg Island have disappeared entirely in the 40 year period of interest. The issue of glacier definition will be discussed as a possible cause of these

  6. Ecological biogeography of southern ocean islands: species-area relationships, human impacts, and conservation

    NARCIS (Netherlands)

    Chown, S.L.; Gremmen, N.J.M.; Gaston, K.J.

    1998-01-01

    Previous studies have concluded that southern ocean islands are anomalous because past glacial extent and current temperature apparently explain most variance in their species richness. Here, the relationships between physical variables and species richness of vascular plants, insects, land and

  7. Genomic timetree and historical biogeography of Caribbean island ameiva lizards (Pholidoscelis: Teiidae)

    OpenAIRE

    Tucker, Derek B.; Hedges, Stephen Blair; Colli, Guarino R.; Pyron, Robert Alexander; Sites, Jack W.

    2017-01-01

    Abstract The phylogenetic relationships and biogeographic history of Caribbean island ameivas (Pholidoscelis) are not well?known because of incomplete sampling, conflicting datasets, and poor support for many clades. Here, we use phylogenomic and mitochondrial DNA datasets to reconstruct a well?supported phylogeny and assess historical colonization patterns in the group. We obtained sequence data from 316 nuclear loci and one mitochondrial marker for 16 of 19 extant species of the Caribbean e...

  8. Conference program and abstracts. International Biogeography Society 6th Biennial Meeting – 9-13 January 2013, Miami, Florida, USA

    Directory of Open Access Journals (Sweden)

    Joaquín Hortal

    2012-12-01

    Full Text Available Proceedings of the Sixth biennial conference of the International Biogeography Society, an international and interdisciplinary society contributing to the advancement of all studies of the geography of nature. Held at Miami, Florida, USA, 9 – 13 January 2013.Abstracts include:(i the Opening, MacArthur & Wilson Award and Alfred Russel Award Plenary Lectures;(ii four symposia entitled "Island Biogeography: New Syntheses", "Beyond Bergmann: New perspectives on the biogeography of traits", "The Convergence of Conservation Paleontology and Biogeography" and "Predicting species and biodiversity in a warmer world: are we doing a good job?";(iii oral presentations from contributed papers on Phylogeography, Marine Biogeography, Biogeography of the Anthropocene, Hot Topics in biogeography, Island Biogeography, Neotropical Biogeography, Global Change Biogeography, Historical and Paleo-biogeography, Conservation Biogeography and Global-Scale Biogeography; and(iv contributions presented as posters on Phylogeography, Geospatial techniques and land cover, Biodiversity gradients and macroecology, Biogeography of traits, Island Biogeography, Neotropical Biogeography, Conservation Biogeography, Disturbance and Disease Biogeography, Climate Change Biogeography and Historical and Paleo-Biogeography.

  9. Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages

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    Schaefer Hanno

    2012-12-01

    Full Text Available Abstract Background Tribe Fabeae comprises about 380 legume species, including some of the most ancient and important crops like lentil, pea, and broad bean. Breeding efforts in legume crops rely on a detailed knowledge of closest wild relatives and geographic origin. Relationships within the tribe, however, are incompletely known and previous molecular results conflicted with the traditional morphology-based classification. Here we analyse the systematics, biogeography, and character evolution in the tribe based on plastid and nuclear DNA sequences. Results Phylogenetic analyses including c. 70% of the species in the tribe show that the genera Vicia and Lathyrus in their current circumscription are not monophyletic: Pisum and Vavilovia are nested in Lathyrus, the genus Lens is nested in Vicia. A small, well-supported clade including Vicia hirsuta, V. sylvatica, and some Mediterranean endemics, is the sister group to all remaining species in the tribe. Fabeae originated in the East Mediterranean region in the Miocene (23–16 million years ago (Ma and spread at least 39 times into Eurasia, seven times to the Americas, twice to tropical Africa and four times to Macaronesia. Broad bean (V. faba and its sister V. paucijuga originated in Asia and might be sister to V. oroboides. Lentil (Lens culinaris ssp. culinaris is of Mediterranean origin and together with eight very close relatives forms a clade that is nested in the core Vicia, where it evolved c. 14 Ma. The Pisum clade is nested in Lathyrus in a grade with the Mediterranean L. gloeosperma, L. neurolobus, and L. nissolia. The extinct Azorean endemic V. dennesiana belongs in section Cracca and is nested among Mediterranean species. According to our ancestral character state reconstruction results, ancestors of Fabeae had a basic chromosome number of 2n=14, an annual life form, and evenly hairy, dorsiventrally compressed styles. Conclusions Fabeae evolved in the Eastern Mediterranean in the

  10. Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages.

    Science.gov (United States)

    Schaefer, Hanno; Hechenleitner, Paulina; Santos-Guerra, Arnoldo; Menezes de Sequeira, Miguel; Pennington, R Toby; Kenicer, Gregory; Carine, Mark A

    2012-12-25

    Tribe Fabeae comprises about 380 legume species, including some of the most ancient and important crops like lentil, pea, and broad bean. Breeding efforts in legume crops rely on a detailed knowledge of closest wild relatives and geographic origin. Relationships within the tribe, however, are incompletely known and previous molecular results conflicted with the traditional morphology-based classification. Here we analyse the systematics, biogeography, and character evolution in the tribe based on plastid and nuclear DNA sequences. Phylogenetic analyses including c. 70% of the species in the tribe show that the genera Vicia and Lathyrus in their current circumscription are not monophyletic: Pisum and Vavilovia are nested in Lathyrus, the genus Lens is nested in Vicia. A small, well-supported clade including Vicia hirsuta, V. sylvatica, and some Mediterranean endemics, is the sister group to all remaining species in the tribe. Fabeae originated in the East Mediterranean region in the Miocene (23-16 million years ago (Ma)) and spread at least 39 times into Eurasia, seven times to the Americas, twice to tropical Africa and four times to Macaronesia. Broad bean (V. faba) and its sister V. paucijuga originated in Asia and might be sister to V. oroboides. Lentil (Lens culinaris ssp. culinaris) is of Mediterranean origin and together with eight very close relatives forms a clade that is nested in the core Vicia, where it evolved c. 14 Ma. The Pisum clade is nested in Lathyrus in a grade with the Mediterranean L. gloeosperma, L. neurolobus, and L. nissolia. The extinct Azorean endemic V. dennesiana belongs in section Cracca and is nested among Mediterranean species. According to our ancestral character state reconstruction results, ancestors of Fabeae had a basic chromosome number of 2n=14, an annual life form, and evenly hairy, dorsiventrally compressed styles. Fabeae evolved in the Eastern Mediterranean in the middle Miocene and spread from there across Eurasia, into

  11. Distribution, autecology and biogeography of Dryopidae and Elmidae (Coleoptera, Dryopoidea in the Balearic Islands

    Directory of Open Access Journals (Sweden)

    Rico, E.

    1998-12-01

    Full Text Available The distribution of the Dryopidae and Elmidae in the Balearic Islands was studied. Three species of Dryopidae —Dryops algiricus (Lucas, 1949, D. gracilis (Karsch, 1881 and D. sulcipennis (Costa, 1883— and one of Elmidae —Oulimnius echinatus Berthélemy, 1979— were found. Bibliographical data of other three species of Dryopidae exist, but their presence is either refuted —Dryops lutulentus (Erichson, 1847— or requires confirmation —Dryops luridus (Erichson, 1847 and D. rufipes (Krynicki, 1832—. Dryops gracilis and D. sulcipennis are recorded for first time in the archipelago. The first autecological data of the different species in the archipelago and a biogeographical analysis are provided.

    Se realiza un estudio sobre la distribución de los Dryopidae y Elmidae en las islas Baleares. Tres especies de Dryopidae —Dryops algiricus (Lucas, 1949, D. gracilis (Karsch, 1881 y D. sulcipennis (Costa, 1883— y una de Elmidae —Oulimnius echinatus Berthélemy, 1979— han sido halladas. Existen datos bibliográficos de otras tres especies de Dryopidae, pero su presencia es excluida —Dryops lutulentus (Erichson, 1847— o se considera que debe ser confirmada —Dryops luridus (Erichson, 1847 y D. rufipes (Krynicki, 1832—. Dryops gracilis y D. sulcipennis se citan por primera vez en el archipiélago. Se aportan los primeros datos sobre la autoecología de las diferentes especies en las islas y se realiza un análisis biogeográfico.

  12. Arthropod gut symbionts from the Balearic Islands: Majorca and Cabrera. Diversity and biogeography

    Directory of Open Access Journals (Sweden)

    Guàrdia Valle, Laia

    2009-12-01

    Full Text Available This study includes a catalogue with all the current data concerning the presence of trichomycetes (sensu lato in Majorca and Cabrera, as well as information on the biology, ecology and biogeographic implications of the insularity for each taxon of these arthropod-gut symbionts. Of the 13 species here reported, 10 are new for the Balearic Islands, including 4 Mesomycetozoan, of which 3 Eccrinales (Astreptonema gammari, Eccrinidus flexilis, Parataeniella dilatata, 1 Amoebidiales (Paramoebidium curvum and 6 kixckellomycotina Harpellales (Genistellospora homothallica, Harpella melusinae, Smittium culisetae, S. simulii, Stachylina grandispora and St. nana; the additional 3 were previously reported elsewhere: Asellaria ligiae (Aslleariales, Legeriomyces rarus and Stipella vigilans (Harpellales, but are here included as indissoluble part of the present Balearic catalogue. All taxa are commented, illustrated and their biogeographic implications are discussed.

    El presente estudio incluye una recopilación de todos los datos concernientes al conocimiento de los tricomicetos (sensu lato en las islas Baleares de Mallorca y Cabrera, incluyendo un catálogo de especies y notas sobre la biología, ecología e implicaciones biogeográficas de su insularidad. De las 13 especies citadas, 10 son nuevas para las Baleares, incluyendo 4 Mesomycetozoos, de los cuales 3 Eccrinales (Astreptonema gammari, Eccrinidus flexilis, Parataeniella dilatata, 1 Amoebidiales (Paramoebidium curvum y 6 Harpellales (kixckellomycotina (Genistellospora homothallica, Harpella melusinae, Smittium culisetae, S. simulii, Stachylina grandispora y St. nana; aunque las 3 especies restantes: Asellaria ligiae (Aslleariales, Legeriomyces rarus y Stipella vigilans (Harpellales fueron citadas anteriormente, se incluyen aquí brevemente como parte del catálogo.

  13. Examining Relationships of Destination Image, Service Quality, e-WOM, and Revisit Intention to Sabang Island, Indonesia

    Directory of Open Access Journals (Sweden)

    Rangga Restu Prayogo

    2016-12-01

    Full Text Available The purpose of this research is to study the relationship among destination image, service quality, e-WOM, and revisit intentions in the tourism industry. A questionnaire given to tourists who visit one of the farrest island in western part of Indonesia, Sabang Island and using sampling through the convenience sampling. A structural equation model (SEM test with WarpPLS 3.0 was used to test the relationship between research variables. This research gathered from 150 respondents. The empirical results from PLS-SEM showed that; the destination image positive affect e-WOM and revisit intention; service quality affect e-WOM and revisit intention; e-WOM positive affect to revisit intention tourists. The implications and future research issues were discussed.

  14. A reconstruction of Palaeo-Macaronesia, with particular reference to the long-term biogeography of the Atlantic island laurel forests

    DEFF Research Database (Denmark)

    Fernández-Palacios, José María; de Nascimento, Lea; Otto, Rüdiger

    2011-01-01

    Macaronesia is a biogeographical region comprising five Atlantic Oceanic archipelagos: the Azores, Madeira, Selvagen (Savage Islands), Canaries and Cape Verde. It has strong affinities with the Atlantic coast of the Iberian Peninsula and the north-western fringes of Africa. This paper re...... the role of these archipelagos as stepping stones and as both repositories of palaeo-endemic forms and crucibles of neo-endemic radiations of plant and animal groups. Our principal focus is on the laurel forest communities, long considered impoverished relicts of the Palaeotropical Tethyan flora....... This account is therefore contextualized by reference to the long-term climatic and biogeographical history of Southern Europe and North Africa and by consideration of the implications of changes in land–sea configuration, climate and ocean circulation for Macaronesian biogeography. We go on to provide...

  15. Magmatic versus tectonic influence in the Eolian arc: the case of Vulcano and Lipari islands revisited

    Science.gov (United States)

    Ruch, Joel; Di Lorenzo, Riccardo; Vezzoli, Luigina Maria; De Rosa, Rosanna; Acocella, Valerio; Catalano, Stefano; Romagnoli, Gino

    2014-05-01

    The prevalent influence of magma versus tectonics for the edification and the evolution of volcanic zones is matter of debate. Here we focus on Vulcano and Lipari, two active volcanic islands located in the central sector of the Eolian arc (North of Sicily). Both systems are influenced by regional tectonics and affected by historical magmatic events taking place along a NS oriented structure, connecting both islands. We revisit and implement previous structural studies performed during the 1980's considering several new geophysical, geochemical and geodynamical findings. Four extensive structural campaigns have been performed on both islands and along the shorelines in 2012-2013 covering about 80% of the possible accessible outcrops. We collected ~500 measurements (e.g. faults, fractures and dikes) at 40 sites. Overall, most of the observed structures are oriented N-S and NNW-SSE, confirming previous studies, however, almost all features are strikingly dominated by an EW-oriented extensive regime, which is a novelty. These findings are supported by kinematic indicators and suggest a predominant dip-slip component (pitch from 80 and 130°) with alternating left and right kinematics. Marginal faulting in most recent formations have been observed, suggesting that the deformation may occur preferentially during transient deformation related to periods of magmatic activity, instead of resulting from continuous regional tectonic processes. Overall, fault and dike planes are characterized by a dominant eastward immersion, suggesting an asymmetric graben-like structure of the entire area. This may be explained by the presence of a topographic gradient connecting both islands to the deep Gioia basin to the East, leading to a preferential ample gravitational collapse. Finally, we propose a model in which the stress field rotates northward. It transits from a pure right lateral strike-slip regime along the Tindari fault zone (tectonic-dominant) to an extensive regime

  16. Revisited

    DEFF Research Database (Denmark)

    Tegtmeier, Silke; Meyer, Verena; Pakura, Stefanie

    2017-01-01

    were captured when they described entrepreneurs. Therefore, this paper aims to revisit gender role stereotypes among young adults. Design/methodology/approach: To measure stereotyping, participants were asked to describe entrepreneurs in general and either women or men in general. The Schein......Purpose: Entrepreneurship is shaped by a male norm, which has been widely demonstrated in qualitative studies. The authors strive to complement these methods by a quantitative approach. First, gender role stereotypes were measured in entrepreneurship. Second, the explicit notions of participants......: The images of men and entrepreneurs show a high and significant congruence (r = 0.803), mostly in those adjectives that are untypical for men and entrepreneurs. The congruence of women and entrepreneurs was low (r = 0.152) and insignificant. Contrary to the participants’ beliefs, their explicit notions did...

  17. On the island biogeography of aliens: a global analysis of the richness of alien plant and bird species on oceanic islands

    Czech Academy of Sciences Publication Activity Database

    Blackburn, T. M.; Delean, S.; Pyšek, Petr; Cassey, P.

    2016-01-01

    Roč. 25, č. 7 (2016), s. 859-868 ISSN 1466-822X R&D Projects: GA ČR GB14-36079G Grant - others:AV ČR(CZ) AP1002 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:67985939 Keywords : plants * birds * island invasions Subject RIV: EH - Ecology, Behaviour Impact factor: 6.045, year: 2016

  18. A second horizon scan of biogeography

    DEFF Research Database (Denmark)

    Dawson, Michael N.; Axmacher, Jan C.; Beierkuhnlein, Carl

    2016-01-01

    (particularly bird and mammal), and geographic (e.g., island, montane) studies of the 1800s. That core is being enriched by large datasets (e.g. of environmental variables, 'omics', species' occurrences, traits) and new techniques (e.g., advances in genetics, remote sensing, modeling) that promote studies...... traditional biogeography journals to multidisciplinary or open access journals. Thus, there are currently many opportunities and challenges as biogeography increasingly addresses human impacts on, and stewardship of, the planet (e.g., Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem...

  19. Moorean tree snail survival revisited: a multi-island genealogical perspective.

    Science.gov (United States)

    Lee, Taehwan; Burch, John B; Coote, Trevor; Pearce-Kelly, Paul; Hickman, Carole; Meyer, Jean-Yves; O Foighil, Diarmaid

    2009-08-18

    The mass extirpation of the island of Moorea's endemic partulid tree snail fauna, following the deliberate introduction of the alien predator Euglandina rosea, represents one of the highest profile conservation crises of the past thirty years. All of the island's partulids were thought to be extirpated by 1987, with five species persisting in zoos, but intensive field surveys have recently detected a number of surviving wild populations. We report here a mitochondrial (mt) phylogenetic estimate of Moorean partulid wild and captive lineage survival calibrated with a reference museum collection that pre-dates the predator's introduction and that also includes a parallel dataset from the neighboring island of Tahiti. Although severe winnowing of Moorea's mt lineage diversity has occurred, seven of eight (six Partula; two Samoana) partulid tip clades remain extant. The extinct mt clade occurred predominantly in the P. suturalis species complex and it represented a major component of Moorea's endemic partulid treespace. Extant Moorean mt clades exhibited a complex spectrum of persistence on Moorea, in captivity, and (in the form of five phylogenetically distinct sister lineages) on Tahiti. Most notably, three Partula taxa, bearing two multi-island mt lineages, have survived decades of E. rosea predation on Moorea (P. taeniata) and in the valleys of Tahiti (P. hyalina and P. clara). Their differential persistence was correlated with intrinsic attributes, such as taxonomy and mt lineages, rather than with their respective within-island distribution patterns. Conservation efforts directed toward Moorean and Tahitian partulids have typically operated within a single island frame of reference, but our discovery of robust genealogical ties among survivors on both islands implies that a multi-island perspective is required. Understanding what genetic and/or ecological factors have enabled Partula taeniata, P. hyalina and P. clara to differentially survive long-term direct

  20. Moorean tree snail survival revisited: a multi-island genealogical perspective

    Directory of Open Access Journals (Sweden)

    Meyer Jean-Yves

    2009-08-01

    Full Text Available Abstract Background The mass extirpation of the island of Moorea's endemic partulid tree snail fauna, following the deliberate introduction of the alien predator Euglandina rosea, represents one of the highest profile conservation crises of the past thirty years. All of the island's partulids were thought to be extirpated by 1987, with five species persisting in zoos, but intensive field surveys have recently detected a number of surviving wild populations. We report here a mitochondrial (mt phylogenetic estimate of Moorean partulid wild and captive lineage survival calibrated with a reference museum collection that pre-dates the predator's introduction and that also includes a parallel dataset from the neighboring island of Tahiti. Results Although severe winnowing of Moorea's mt lineage diversity has occurred, seven of eight (six Partula; two Samoana partulid tip clades remain extant. The extinct mt clade occurred predominantly in the P. suturalis species complex and it represented a major component of Moorea's endemic partulid treespace. Extant Moorean mt clades exhibited a complex spectrum of persistence on Moorea, in captivity, and (in the form of five phylogenetically distinct sister lineages on Tahiti. Most notably, three Partula taxa, bearing two multi-island mt lineages, have survived decades of E. rosea predation on Moorea (P. taeniata and in the valleys of Tahiti (P. hyalina and P. clara. Their differential persistence was correlated with intrinsic attributes, such as taxonomy and mt lineages, rather than with their respective within-island distribution patterns. Conclusion Conservation efforts directed toward Moorean and Tahitian partulids have typically operated within a single island frame of reference, but our discovery of robust genealogical ties among survivors on both islands implies that a multi-island perspective is required. Understanding what genetic and/or ecological factors have enabled Partula taeniata, P. hyalina and P

  1. Transferring and implementing the general dynamic model of oceanic island biogeography at the scale of island fragments: the role of geological age and topography in plant diversification in the Canaries

    DEFF Research Database (Denmark)

    Otto, Rüdiger; Whittaker, Robert J.; von Gaisberg, Markus

    2016-01-01

    ontogenies, featuring surfaces of varying age. Here, we extend the GDM to apply at a local scale within islands, and test the predictions analytically within individual islands. Location El Hierro, La Palma and Tenerife (Canary Islands). Methods Following the GDM logic, we derive predictions...

  2. Backscatter 0.5m TIFF Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography...

  3. MHD Equilibrium with Reversed Current Density and Magnetic Islands Revisited: the Vacuum Vector Potential Calculus

    Science.gov (United States)

    L. Braga, F.

    2013-10-01

    The solution of Grad-Shafranov equation determines the stationary behavior of fusion plasma inside a tokamak. To solve the equation it is necessary to know the toroidal current density profile. Recent works show that it is possible to determine a magnetohydrodynamic (MHD) equilibrium with reversed current density (RCD) profiles that presents magnetic islands. In this work we show analytical MHD equilibrium with a RCD profile and analyze the structure of the vacuum vector potential associated with these equilibria using the virtual casing principle.

  4. Three Mile Island epidemiologic radiation dose assessment revisited: 25 years after the accident.

    Science.gov (United States)

    Field, R William

    2005-01-01

    Over the past 25 years, public health concerns following the Three Mile Island (TMI) accident prompted several epidemiologic investigations in the vicinity of TMI. One of these studies is ongoing. This commentary suggests that the major source of radiation exposure to the population has been ignored as a potential confounding factor or effect modifying factor in previous and ongoing TMI epidemiologic studies that explore whether or not TMI accidental plant radiation releases caused an increase in lung cancer in the community around TMI. The commentary also documents the observation that the counties around TMI have the highest regional radon potential in the United States and concludes that radon progeny exposure should be included as part of the overall radiation dose assessment in future studies of radiation-induced lung cancer resulting from the TMI accident.

  5. Three Mile Island epidemiologic radiation dose assessment revisited: 25 years after the accident

    International Nuclear Information System (INIS)

    Field, R. W.

    2005-01-01

    Over the past 25 years, public health concerns following the Three Mile Island (TMI) accident prompted several epidemiologic investigations in the vicinity of TMI. One of these studies is ongoing. This commentary suggests that the major source of radiation exposure to the population has been ignored as a potential confounding factor or effect modifying factor in previous and ongoing TMI epidemiologic studies that explore whether or not TMI accidental plant radiation releases caused an increase in lung cancer in the community around TMI. The commentary also documents the observation that the counties around TMI have the highest regional radon potential in the United States and concludes that radon progeny exposure should be included as part of the overall radiation dose assessment in future studies of radiation-induced lung cancer resulting from the TMI accident. (authors)

  6. The theory of the insular balance in biogeography and conservation

    International Nuclear Information System (INIS)

    Pozo, Carmen; Llorente Bousquets, Jorge

    2002-01-01

    Based on the revision of abundant bibliography, commentaries are made in relation to the eco geographical island theory proposed by Macarthur- Wilson and over its impact as well as the implications and limitations generated in the application of the theory in research related to biogeography, ecology, and conservation biology. We emphasize that the model served to stimulate a great deal of research and generate new concepts, such as Minimal Viable population (MVP)

  7. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geotiff represents a 0.5 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography...

  8. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team...

  9. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2005 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team...

  10. Biogeography of Hysterangiales (Phallomycetidae, Basidiomycota)

    Science.gov (United States)

    Kentaro Hosaka; Michael A. Castellano; Joseph W. Spatafora

    2008-01-01

    To understand the biogeography of truffle-like fungi, DNA sequences were analysed from representative taxa of Hysterangiales. Multigene phylogenies and the results of ancestral area reconstructions are consistent with the hypothesis of an Australian, or eastern Gondwanan, origin of Hysterangiales with subsequent range expansions to the Northern Hemisphere. However,...

  11. Ecology and Evolution: Islands of Change.

    Science.gov (United States)

    Benz, Richard

    This book was designed for middle and junior high school science classes and focuses on island biogeography, ecology, and evolution. Sections include: (1) "Galapagos: Frame of Reference"; (2) "Ecology and Islands"; and (3) "Evolution." Nineteen standards-based activities use the Galapagos Islands as a running theme…

  12. The effects of island ontogeny on species diversity and phylogeny

    NARCIS (Netherlands)

    Valente, Luis M.; Etienne, Rampal S.; Phillimore, Albert B.

    2014-01-01

    A major goal of island biogeography is to understand how island communities are assembled over time. However, we know little about the influence of variable area and ecological opportunity on island biotas over geological time-scales. Islands have limited life spans, and it has been posited that

  13. EMI – young HIMU rock association at the Cape Verde Islands revisited: on the role of oceanic carbonatites

    DEFF Research Database (Denmark)

    Holm, Paul Martin; Kokfelt, Thomas Find; Dyhr, Charlotte Thorup

    Isotopic compositions of the Cape Verde (Central) hotspot magmas indicate a predominant influence from young HIMU and EM-1 type sources. Detailed modelling based on high precision Sr, Nd and Pb (DS) isotope data suggests that seven local mantle end-members explain the isotopic variation within five...... HIMU. Carbonatites are widespread throughout Cape Verde Islands but volumetrically minor and are low in Ti, K, and Rb. In several silicate rocks from all three islands low Ti/Eu is evidence for a carbonatite component and is accompanied by LREE enrichment, and relatively low K and Rb. Other rocks have...

  14. Revisiting recent history: records of occurrence and expansion of the European green crab across Prince Edward Island, Atlantic Canada

    Directory of Open Access Journals (Sweden)

    Luke A. Poirier

    2017-11-01

    Full Text Available Abstract Background Late in the 1990s, the non-indigenous European green crab (Carcinus maenas colonized the shorelines of eastern Prince Edward Island, in Atlantic Canada. Due to concerns of further spread into productive shellfish habitats, an annual survey was conducted between 2000 and 2013 to detect a potential range expansion of this species. We compiled and analyzed that data and document green crab expansion using records of annual occurrence and relative density. Methods Surveys were conducted during the fall season of each year by deploying baited traps at 29 sites along the island’s two main shorelines (north and south shores. These sites were selected based on areas deemed more likely to be invaded by the green crab. Raw data per site and date was transformed to catch per unit effort (CPUE to estimate relative abundances. Results Populations of this species showed an uneven westward expansion along the north and south shores. Expansion rates changed among years but, overall, crab abundance was higher and changes in abundance were faster along the south shore than the north shore of the island. The westward expansion continues until this day. Conclusions Based on the information compiled we hypothesize that the dissimilarity in range expansion rate was related to the availability of suitable habitat to sustain large green crab populations along the south shore. We also discuss implications of this expansion for commercial shellfish and native coastal communities.

  15. St. Matthew Island reindeer crash revisited: Their demise was not nigh—but then, why did they die?

    Directory of Open Access Journals (Sweden)

    Frank L. Miller

    2005-05-01

    Full Text Available Twenty-nine yearling reindeer (Rangifer tarandus were released on St. Matthew Island in the Bering Sea Wildlife Refuge in 1944: 24 females and five males. They were reported to have increased to 1350 reindeer by summer 1957 and to 6000 by summer 1963. The 6000 reindeer on St. Matthew Island in summer 1963 were then reduced by 99% to 42 by summer 1966. The evidence suggests that after growing at a high average annual rate of lamda = 1.32 for 19 years, the entire die-off occurred in winter 1963—64, making it the largest single-year crash ever recorded in any R. tarandus population. Although a supposedly meaningful decline in successful reproduction and early survival of calves was originally reported for the population between 1957 and 1963, our reevaluation indicates this is an error resulting from the wrong sample being used in the between-year comparison. The quantitative data indicate no meaningful change occurred, and the calf:cow ratio was about 60 calves:100 cows in both 1957 and 1963. Calf production and survival were high up to the crash, and in the die-off population the age distribution (72%, 1—3 years old and the sex ratio (69 males:100 females reflected a still fast-growing R. tarandus population. All of these parameters do not support the hypothesis that the limited abundance of the absolute food supply was at a lethal level between 1957 and 1963 or in winter 1963—64. We now know from other studies that a high density of R. tarandus is not a prerequisite for a major single-year winter die-off. Existing population dynamics data do not support lack of lichens as a major causative factor in this single-year crash. If a decline had been caused by the limitation of the absolute food supply, it would have followed a multi-year pattern—it would not have been a single-year event. There was no evidence of a sudden, massive, island-wide loss of the absolute food supply, or that its nutritional value was inadequate for sustaining the

  16. Influences of oceanic islands and the Pleistocene on the biogeography and evolution of two groups of Australasian parrots (Aves: Psittaciformes: Eclectus roratus, Trichoglossus haematodus complex. Rapid evolution and implications for taxonomy and conservation

    Directory of Open Access Journals (Sweden)

    Braun Michael P.

    2016-08-01

    Full Text Available The Australasian region is a centre of biodiversity and endemism, mainly based on the tropical climate in combination with the large amount of islands. During the Pleistocene, islands of the Sahul Shelf (Australia, New Guinea, Aru Islands had been part of the same land mass, while islands within the Wallacea (Lesser Sunda Islands, Moluccas, Sulawesi etc. remained isolated. We investigated biogeographical avian diversification patterns of two species complexes across the Wallacea and the Sahul Shelf: the Eclectus Parrot Eclectus roratus Wagler, 1832, and the Rainbow Lorikeet Trichoglossus haematodus Linnaeus, 1771. Both species are represented by a large number of described geographical subspecies. We used mitochondrial cytochrome b (cyt b sequences for phylogenetic and network analysis to detect biogeographic roles of islands and avian diversification patterns. The number of threatened taxa in this region is increasing rapidly and there is an urgent need for (sub-species conservation in this region. Our study provides first genetic evidence for treating several island taxa as distinct species. In both species complexes similar genetic patterns were detected. Genetic diversification was higher across the islands of the Wallacea than across the islands of the Sahul Shelf. Divergence in E. roratus can be dated back about 1.38 million years ago, whereas in the younger T. haematodus it was 0.80 million years ago. Long distance dispersal was the most likely event for distribution patterns across the Wallacea and Sahul Shelf. The geographic origin of the species-complex Eclectus roratus spp. is supposed to be Wallacean, but for the species-complex Trichoglossus haematodus spp. it is supposed to be non-Wallacean. Trichoglossus euteles, so far considered a distinct species, clearly belongs to the Trichoglossus-haematodus-complex. The only case of sympatry in the complex is the distribution of T. (h. euteles and T. h. capistratus on Timor, which means a

  17. Species invasions on islands: searching for general patterns and principles

    Science.gov (United States)

    Q. Guo

    2014-01-01

    Numerous islands worldwide are being increasingly invaded by exotic species. However, the effects of invading species on native floras remain underexplored, particularly whether island biogeography theory is applicable to native, exotic, and the newly assembled floras. Inter-group comparisons across different regions or island groups through a collection of individual...

  18. Fishes of the Vitória-Trindade Chain: Biodiversity, Biogeography and Evolution

    OpenAIRE

    Pinheiro, Hudson Tercio

    2016-01-01

    Studies on the ecology and biogeography of seamounts and oceanic islands have advanced substantially in the last 60 years. However, few seamounts have been scientifically characterized, with basic aspects of their biodiversity still unknown and many hypotheses not empirically tested. Consequently, the role of seamounts in the evolution for marine species is still unclear. In the south Atlantic, the Vitória-Trindade Chain (VTC) extends ca. 1,200 km offshore the Brazilian coast. For a long time...

  19. Volcanic evolution of central Basse-Terre Island revisited on the basis of new geochronology and geomorphology data

    Science.gov (United States)

    Ricci, J.; Quidelleur, X.; Lahitte, P.

    2015-10-01

    Twenty-six new and seven previous K-Ar ages obtained on groundmass separates for samples from the Axial Chain massif (Guadeloupe, F.W.I.), associated with geomorphological investigations, allow us to propose a new model of the volcanic evolution of the central part of Basse-Terre Island. The Axial Chain is composed of four edifices, Moustique, Matéliane, Capesterre, and Icaque mounts, showing coeval activity from 681 ± 12 to 509 ± 10 ka, which contradicts a previous hypothesis that flank collapse affected them successively. Our geomorphological reconstruction shows that the Axial Chain can be considered as a single large volcano, named the Southern Axial Chain volcano (SCA), rather than a succession of several smaller volcanoes. It raises questions regarding the formation of a large depression within the SCA volcano, prior to the construction of the Sans-Toucher volcano between 451 ± 13 and 412 ± 8 ka. Given presently available evidence, a slump affecting the western part of the SCA volcano is the most probable scenario to reconcile the complete age dataset and the present-day morphology of central Basse-Terre. Finally, our study shows that the SCA volcano had a post-activity volume of 90 km3, implying a construction rate of 0.5 km3/kyr. This value strongly constrains interpretations of magma generation processes throughout the Lesser Antilles arc.

  20. Biogeography

    OpenAIRE

    Palmer, Carol

    2014-01-01

    Jordan has a remarkably diverse flora with approximately 2,500 plant species. This diversity reflects the transitional position of the country between semi-arid and arid climatological zones. The overall climate, however, is broadly Mediterranean, characterized by the division of the year into a mild rainy winter and hot dry summer. Al-Eisawi (1985), following Long (1957), identifies nine bioclimatic regions, broadly grouped into four main clusters: Sub-humid Mediterranean, Semi-arid Mediterr...

  1. Backscatter 0.5m TIFF Mosaic of St. Thomas, US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the south shore of St. Thomas, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team and...

  2. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Thomas, US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the south shore of St. Thomas, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team and...

  3. A second horizon scan of biogeography: Golden Ages, Midas touches, and the Red Queen

    Directory of Open Access Journals (Sweden)

    Michael N Dawson

    2016-12-01

    Full Text Available Are we entering a new ‘Golden Age’ of biogeography, with continued development of infrastructure and ideas? We highlight recent developments, and the challenges and opportunities they bring, in light of the snapshot provided by the 7th biennial meeting of the International Biogeography Society (IBS 2015. We summarize themes in and across 15 symposia using narrative analysis and word clouds, which we complement with recent publication trends and ‘research fronts’. We find that biogeography is still strongly defined by core sub-disciplines that reflect its origins in botanical, zoological (particularly bird and mammal, and geographic (e.g., island, montane studies of the 1800s. That core is being enriched by large datasets (e.g. of environmental variables, ‘omics’, species’ occurrences, traits and new techniques (e.g., advances in genetics, remote sensing, modeling that promote studies with increasing detail and at increasing scales; disciplinary breadth is being diversified (e.g., by developments in paleobiogeography and microbiology and integrated through the transfer of approaches and sharing of theory (e.g., spatial modeling and phylogenetics in evolutionary–ecological contexts. Yet some subdisciplines remain on the fringe (e.g., marine biogeography, deep-time paleobiogeography, new horizons and new theory may be overshadowed by popular techniques (e.g., species distribution modelling, and hypotheses, data, and analyses may each be wanting. Trends in publication suggest a shift away from traditional biogeography journals to multidisciplinary or open access journals. Thus, there are currently many opportunities and challenges as biogeography increasingly addresses human impacts on, and stewardship of, the planet (e.g., Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. As in the past, biogeographers doubtless will continue to be engaged by new data and methods in exploring the nexus between biology

  4. Conservation biogeography - foundations, concepts and challenges

    DEFF Research Database (Denmark)

    Richardson, Timothy; Whittaker, R.J.; Whittaker, Robert J.

    2010-01-01

    Conservation biogeography involves the application of biogeographical principles, theories, and analyses to problems regarding biodiversity conservation. The field was formally defined in 2005, and considerable research has been conducted in the ensuing 5 years. This editorial sets the context...... for 16 contributions in a special issue of Diversity and Distributions on developments and challenges in conservation biogeography. Papers are grouped into the following main themes: species distribution modelling; data requirements; approaches for assigning conservation priorities; approaches...... for integrating information from numerous disparate sources; special challenges involving invasive species; and the crucial issue of determining how elements of biodiversity are likely to respond to rapid climate change. One paper provides a synthesis of requirements for a robust conservation biogeography...

  5. Microbial biogeography: putting microorganisms on the map.

    Science.gov (United States)

    Martiny, Jennifer B Hughes; Bohannan, Brendan J M; Brown, James H; Colwell, Robert K; Fuhrman, Jed A; Green, Jessica L; Horner-Devine, M Claire; Kane, Matthew; Krumins, Jennifer Adams; Kuske, Cheryl R; Morin, Peter J; Naeem, Shahid; Ovreås, Lise; Reysenbach, Anna-Louise; Smith, Val H; Staley, James T

    2006-02-01

    We review the biogeography of microorganisms in light of the biogeography of macroorganisms. A large body of research supports the idea that free-living microbial taxa exhibit biogeographic patterns. Current evidence confirms that, as proposed by the Baas-Becking hypothesis, 'the environment selects' and is, in part, responsible for spatial variation in microbial diversity. However, recent studies also dispute the idea that 'everything is everywhere'. We also consider how the processes that generate and maintain biogeographic patterns in macroorganisms could operate in the microbial world.

  6. Improving the performance of the Egyptian second testing nuclear research reactor using interval type-2 fuzzy logic controller tuned by modified biogeography-based optimization

    Energy Technology Data Exchange (ETDEWEB)

    Sayed, M.M., E-mail: M.M.Sayed@ieee.org; Saad, M.S.; Emara, H.M.; Abou El-Zahab, E.E.

    2013-09-15

    Highlights: • A modified version of the BBO was proposed. • A novel method for interval type-2 FLC design tuned by MBBO was proposed. • The performance of the ETRR-2 was improved by using IT2FLC tuned by MBBO. -- Abstract: Power stabilization is a critical issue in nuclear reactors. The conventional proportional derivative (PD) controller is currently used in the Egyptian second testing research reactor (ETRR-2). In this paper, we propose a modified biogeography-based optimization (MBBO) algorithm to design the interval type-2 fuzzy logic controller (IT2FLC) to improve the performance of the Egyptian second testing research reactor (ETRR-2). Biogeography-based optimization (BBO) is a novel evolutionary algorithm that is based on the mathematical models of biogeography. Biogeography is the study of the geographical distribution of biological organisms. In the BBO model, problem solutions are represented as islands, and the sharing of features between solutions is represented as immigration and emigration between the islands. A modified version of the BBO is applied to design the IT2FLC to get the optimal parameters of the membership functions of the controller. We test the optimal IT2FLC obtained by modified biogeography-based optimization (MBBO) using the integral square error (ISE) and is compared with the currently used PD controller.

  7. Island Species Richness Increases with Habitat Diversity

    NARCIS (Netherlands)

    Hortal, J.; Triantis, K.A.; Meiri, S.; Thebault, E.M.C.; Sfenthourakis, S.

    2009-01-01

    Species richness is commonly thought to increase with habitat diversity. However, a recent theoretical model aiming to unify niche and island biogeography theories predicted a hump-shaped relationship between richness and habitat diversity. Given the contradiction between model results and previous

  8. Microbial Biogeography of the Arctic Cryosphere

    DEFF Research Database (Denmark)

    Hauptmann, Aviaja Zenia Edna Lyberth

    communities. This has considerably improved our understanding that even harsh and seemingly barren environments such as the cryosphere, the frozen parts of our planet, is inhabited by diverse life. This thesis presents three studies in microbial biogeography of the Arctic cryosphere utilizing a range of NGS...

  9. NOAA TIFF Graphic - 0.5 meter Backscatter Mosaic of St. John, U.S. Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the southern shore of St. John, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team and...

  10. Current insights into phage biodiversity and biogeography.

    Science.gov (United States)

    Thurber, Rebecca Vega

    2009-10-01

    Phages exert tremendous ecological and evolutionary forces directly on their bacterial hosts. Phage induced cell lysis also indirectly contributes to organic and inorganic nutrient recycling. Phage abundance, diversity, and distribution are therefore important parameters in ecosystem function. The assumption that phage consortia are ubiquitous and homogenous across habitats (everything is everywhere) is currently being re-evaluated. New studies on phage biogeography have found that some phages are globally distributed while others are unique and perhaps endemic to specific environments. Furthermore, advances in technology have allowed scientists to conduct experiments aimed at analyzing phage consortia over temporal scales, and surprisingly have found reoccurring patterns. This review discusses currents in the field of phage ecology with particular focus on efforts to characterize phage diversity and biogeography across various spatial and temporal scales.

  11. Lakatos Revisited.

    Science.gov (United States)

    Court, Deborah

    1999-01-01

    Revisits and reviews Imre Lakatos' ideas on "Falsification and the Methodology of Scientific Research Programmes." Suggests that Lakatos' framework offers an insightful way of looking at the relationship between theory and research that is relevant not only for evaluating research programs in theoretical physics, but in the social…

  12. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Grammanik Bank - East (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of Grammanik Bank, south of St. Thomas, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  13. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Mid Shelf Reef (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the Mid Shelf Reef south of St. Thomas, US Virgin IslandsNOAA's NOS/NCCOS/CCMA Biogeography Team,...

  14. NOAA TIFF Image - 1 m Backscatter Mosaic of the St. John Shelf, U.S. Virgin Islands, Project NF-10-03, 2010, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the St. John Shelf, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in collaboration...

  15. NOAA ESRI Geotiff - NOAA ESRI Geotiff - 3 m Backscatter Mosaic of Mona Island, Puerto Rico, Project NF-08-04, UTM 19N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of selected portions of seafloor around Mona Island, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography...

  16. NOAA TIFF Graphic - 0.5 meter Backscatter Mosaic of St. John, U.S. Virgin Islands, 2004 (NCEI Accession 0131850)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the southern shore of St. John, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team and...

  17. NOAA ESRI Grid - NOAA ESRI GRID - 3 m Backscatter Mosaic of Mona Island, Puerto Rico, Project NF-08-04, UTM 19N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of selected portions of seafloor around Mona Island, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography...

  18. A roadmap for island biology

    DEFF Research Database (Denmark)

    Patino, Jairo; Whittaker, Robert J.; Borges, Paulo A.V.

    2017-01-01

    Aims: The 50th anniversary of the publication of the seminal book, The Theory of Island Biogeography, by Robert H. MacArthur and Edward O. Wilson, is a timely moment to review and identify key research foci that could advance island biology. Here, we take a collaborative horizon-scanning approach...... to identify 50 fundamental questions for the continued development of the field. Location: Worldwide. Methods: We adapted a well-established methodology of horizon scanning to identify priority research questions in island biology, and initiated it during the Island Biology 2016 conference held in the Azores......); global change (5); conservation and management policies (5); and invasive alien species (4). Main conclusions: Collectively, this cross-disciplinary set of topics covering the 50 fundamental questions has the potential to stimulate and guide future research in island biology. By covering fields ranging...

  19. Biogeography of thermophilic phototrophic bacteria belonging to Roseiflexus genus.

    Science.gov (United States)

    Gaisin, Vasil A; Grouzdev, Denis S; Namsaraev, Zorigto B; Sukhacheva, Marina V; Gorlenko, Vladimir M; Kuznetsov, Boris B

    2016-03-01

    Isolated environments such as hot springs are particularly interesting for studying the microbial biogeography. These environments create an 'island effect' leading to genetic divergence. We studied the phylogeographic pattern of thermophilic anoxygenic phototrophic bacteria, belonging to the Roseiflexus genus. The main characteristic of the observed pattern was geographic and geochronologic fidelity to the hot springs within Circum-Pacific and Alpine-Himalayan-Indonesian orogenic belts. Mantel test revealed a correlation between genetic divergence and geographic distance among the phylotypes. Cluster analysis revealed a regional differentiation of the global phylogenetic pattern. The phylogeographic pattern is in correlation with geochronologic events during the break up of Pangaea that led to the modern configuration of continents. To our knowledge this is the first geochronological scenario of intercontinental prokaryotic taxon divergence. The existence of the modern phylogeographic pattern contradicts with the existence of the ancient evolutionary history of the Roseiflexus group proposed on the basis of its deep-branching phylogenetic position. These facts indicate that evolutionary rates in Roseiflexus varied over a wide range. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Molecular systematics and historical biogeography of tree boas (Corallus spp.).

    Science.gov (United States)

    Colston, Timothy J; Grazziotin, Felipe G; Shepard, Donald B; Vitt, Laurie J; Colli, Guarino R; Henderson, Robert W; Blair Hedges, S; Bonatto, Sandro; Zaher, Hussam; Noonan, Brice P; Burbrink, Frank T

    2013-03-01

    Inferring the evolutionary and biogeographic history of taxa occurring in a particular region is one way to determine the processes by which the biodiversity of that region originated. Tree boas of the genus Corallus are an ancient clade and occur throughout Central and South America and the Lesser Antilles, making it an excellent group for investigating Neotropical biogeography. Using sequenced portions of two mitochondrial and three nuclear loci for individuals of all recognized species of Corallus, we infer phylogenetic relationships, present the first molecular analysis of the phylogenetic placement of the enigmatic C. cropanii, develop a time-calibrated phylogeny, and explore the biogeographic history of the genus. We found that Corallus diversified within mainland South America, via over-water dispersals to the Lesser Antilles and Central America, and via the traditionally recognized Panamanian land bridge. Divergence time estimates reject the South American Caribbean-Track as a general biogeographic model for Corallus and implicate a role for events during the Oligocene and Miocene in diversification such as marine incursions and the uplift of the Andes. Our findings also suggest that recognition of the island endemic species, C. grenadensis and C. cookii, is questionable as they are nested within the widely distributed species, C. hortulanus. Our results highlight the importance of using widespread taxa when forming and testing biogeographic hypotheses in complex regions and further illustrate the difficulty of forming broadly applicable hypotheses regarding patterns of diversification in the Neotropical region. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Barrier displacement on a neutral landscape: Towards a theory of continental biogeography

    Science.gov (United States)

    Albert, James S.; Schoolmaster, Donald; Tagliacollo, Victor; Duke-Sylvester, Scott M.

    2017-01-01

    Macroevolutionary theory posits three processes leading to lineage diversification and the formation of regional biotas: dispersal (species geographic range expansion), speciation (species lineage splitting), and extinction (species lineage termination). The Theory of Island Biogeography (TIB) predicts species richness values using just two of these processes; dispersal and extinction. Yet most species on Earth live on continents or continental shelves, and the dynamics of evolutionary diversification at regional and continental scales are qualitatively different from those that govern the formation of species richness on biogeographic islands. Certain geomorphological processes operating perennially on continental platforms displace barriers to gene flow and organismal dispersal, and affect all three terms of macroevolutionary diversification. For example, uplift of a dissected landscape and river capture both merge and separate portions of adjacent areas, allowing dispersal and larger geographic ranges, vicariant speciation and smaller geographic ranges, and extinction when range sizes are subdivided below a minimum persistence threshold.

  2. Comparative Ecophysiology and Evolutionary Biology of Island and Mainland Chaparral Communities

    OpenAIRE

    Ramirez, Aaron Robert

    2015-01-01

    The unique nature of island ecosystems have fascinated generations of naturalists, ecologists, and evolutionary biologists. Studying island systems led to the development of keystone biological theories including: Darwin and Wallace's theories of natural selection, Carlquist's insights into the biology of adaptive radiations, MacArthur and Wilson's theory of island biogeography, and many others. Utilizing islands as natural laboratories allows us to discover the underlying fabric of ecology a...

  3. Sensemaking Revisited

    DEFF Research Database (Denmark)

    Holt, Robin; Cornelissen, Joep

    2014-01-01

    We critique and extend theory on organizational sensemaking around three themes. First, we investigate sense arising non-productively and so beyond any instrumental relationship with things; second, we consider how sense is experienced through mood as well as our cognitive skills of manipulation ...... research by revisiting Weick’s seminal reading of Norman Maclean’s book surrounding the tragic events of a 1949 forest fire at Mann Gulch, USA....

  4. Special issue: Comparative biogeography of Neotropical primates.

    Science.gov (United States)

    Lynch Alfaro, Jessica W; Cortés-Ortiz, Liliana; Di Fiore, Anthony; Boubli, Jean P

    2015-01-01

    New research presented in this special issue of Molecular Phylogenetics and Evolution on the "Phylogeny and Biogeography of Neotropical Primates" greatly improves our understanding of the evolutionary history of the New World monkeys and provides insights into the multiple platyrrhine radiations, diversifications, extinctions, and recolonizations that have taken place over time and over space in the Neotropics. Here, we synthesize genetic and biogeographic research from the past several years to construct an overarching hypothesis for platyrrhine evolution. We also highlight continuing controversies in Neotropical primate biogeography, such as whether the location of origin of platyrrhines was Africa or Asia; whether Patagonian fossil primates are stem or crown platyrrhines; and whether cis- and trans-Andean Neotropical primates were subject to vicariance through Andes mountain building, or instead diversified through isolation in mountain valleys after skirting around the Andes on the northwestern coast of South America. We also consider the role of the Amazon River and its major tributaries in shaping platyrrhine biodiversity, and how and when primates from the Amazon reached the Atlantic Forest. A key focus is on primate colonizations and extirpations in Central America, the Andes, and the seasonally dry tropical forests and savannas (such as the Llanos, Caatinga, and Cerrado habitats), all ecosystems that have been understudied up until now for primates. We suggest that most primates currently inhabiting drier open habitats are relatively recent arrivals, having expanded from rainforest habitats in the Pleistocene. We point to the Pitheciidae as the taxonomic group most in need of further phylogenetic and biogeographic research. Additionally, genomic studies on the Platyrrhini are deeply needed and are expected to bring new surprises and insights to the field of Neotropical primate biogeography. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Historical biogeography sets the foundation for contemporary conservation of martens (genus Martes) in northwestern North America

    Science.gov (United States)

    Dawson, Natalie G.; Colella, Jocelyn P.; Small, Maurine P.; Stone, Karen D.; Talbot, Sandra L.; Cook, Joseph A.

    2017-01-01

    Effective conservation of insular populations requires careful consideration of biogeography, including colonization histories and patterns of endemism. Across the Pacific Northwest of North America, Pacific martens (Martes caurina) and American pine martens (Martes americana) are parapatric sister species with distinctive postglacial histories. Using mitochondrial DNA and 12 nuclear microsatellite loci, we examine processes of island colonization and anthropogenic introductions across 25 populations of martens. Along the North Pacific Coast (NPC), M. caurina is now found on only 2 islands, whereas M. americana occurs on mainland Alaska and British Columbia and multiple associated islands. Island populations of M. caurina have a longer history of isolation reflected in divergent haplotypes, private microsatellite alleles, and relatively low within-population diversity. In contrast, insular M. americanahave lower among-population divergence and higher metrics of within-population diversity. On some NPC islands, introductions of M. americana may be related to decline of M. caurina. Long-term persistence of these species likely has been influenced by anthropogenic manipulations, including wildlife translocations and industrial-scale deforestation, yet, the distinctive histories of these martens have not been incorporated into natural resource policies.

  6. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Grammanik Bank - East (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of Grammanik Bank, south of St. Thomas, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  7. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Mid Shelf Reef (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the Mid Shelf Reef south of St. Thomas, US Virgin IslandsNOAA's NOS/NCCOS/CCMA Biogeography Team,...

  8. NOAA TIFF Image - 1 m Backscatter Mosaic of the Virgin Passage and the St. John Shelf, U.S. Virgin Islands, Project NF-10-03, 2010, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Virgin Passage in the US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  9. NOAA TIFF Image - 1 m Backscatter Mosaic of the Virgin Passage and the St. John Shelf, U.S. Virgin Islands, Project NF-10-03, 2010, UTM 20 WGS84 (NCEI Accession 0131854)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Virgin Passage in the US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  10. NOAA TIFF Image - 3 m Backscatter Mosaic of the north shore of St. Croix, U.S. Virgin Islands, Project NF-06-03, 2006, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of the north shore of St. Croix, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  11. NOAA TIFF Image - 1 m Backscatter Mosaic of the St. John Shelf, U.S. Virgin Islands, Project NF-10-03, 2010, UTM 20 WGS84 (NCEI Accession 0131854)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the St. John Shelf, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in collaboration...

  12. Biogeography-Based Optimization with Orthogonal Crossover

    Directory of Open Access Journals (Sweden)

    Quanxi Feng

    2013-01-01

    Full Text Available Biogeography-based optimization (BBO is a new biogeography inspired, population-based algorithm, which mainly uses migration operator to share information among solutions. Similar to crossover operator in genetic algorithm, migration operator is a probabilistic operator and only generates the vertex of a hyperrectangle defined by the emigration and immigration vectors. Therefore, the exploration ability of BBO may be limited. Orthogonal crossover operator with quantization technique (QOX is based on orthogonal design and can generate representative solution in solution space. In this paper, a BBO variant is presented through embedding the QOX operator in BBO algorithm. Additionally, a modified migration equation is used to improve the population diversity. Several experiments are conducted on 23 benchmark functions. Experimental results show that the proposed algorithm is capable of locating the optimal or closed-to-optimal solution. Comparisons with other variants of BBO algorithms and state-of-the-art orthogonal-based evolutionary algorithms demonstrate that our proposed algorithm possesses faster global convergence rate, high-precision solution, and stronger robustness. Finally, the analysis result of the performance of QOX indicates that QOX plays a key role in the proposed algorithm.

  13. Biogeography of the Cicadas (Hemiptera: Cicadidae of North America, North of Mexico

    Directory of Open Access Journals (Sweden)

    Allen F. Sanborn

    2013-04-01

    Full Text Available We describe and illustrate the biogeography of the cicadas inhabiting continental North America, north of Mexico. Species distributions were determined through our collecting efforts as well as label data from more than 110 institutional collections. The status of subspecies is discussed with respect to their distributions. As we have shown over limited geographic areas, the distribution of individual species is related to the habitat in which they are found. We discuss the biogeography of the genera with respect to their phylogenetic relationships. California is the state with the greatest alpha diversity (89 species, 46.6% of taxa and unique species (35 species, 18.3% of taxa. Texas, Arizona, Colorado and Utah are the states with the next greatest alpha diversity with Texas, Arizona and Utah being next for unique species diversity. Maine, New Hampshire and Rhode Island are the states with the least amount of cicada diversity. Diversity is greatest in states and areas where there is a diversity of plant communities and habitats within these communities. Mountainous terrain also coincides with increases in diversity. Several regions of the focus area require additional collection efforts to fill in the distributions of several species.

  14. Oceanic protists with different forms of acquired phototrophy display contrasting biogeographies and abundance

    DEFF Research Database (Denmark)

    Leles, Suzanne; Mitra, Aditee; Flynn, Kevin J.

    2017-01-01

    This first comprehensive analysis of the global biogeography of marine protistan plankton with acquired phototrophy shows these mixotrophic organisms to be ubiquitous and abundant; however, their biogeography differs markedly between different functional groups. These mixotrophs, lacking a consti...

  15. Oceanic protists with different forms of acquired phototrophy display contrasting biogeographies and abundance

    NARCIS (Netherlands)

    Leles, S. G.; Mitra, A.; Flynn, K. J.; Stoecker, D. K.; Hansen, P. J.; Calbet, A.; McManus, G. B.; Sanders, R. W.; Caron, D. A.; Not, F.; Hallegraeff, G. M.; Pitta, P.; Raven, J. A.; Johnson, M. D.; Glibert, P. M.; Våge, S.

    2017-01-01

    This first comprehensive analysis of the global biogeography of marine protistan plankton with acquired phototrophy shows these mixotrophic organisms to be ubiquitous and abundant; however, their biogeography differs markedly between different functional groups. These mixotrophs, lacking a

  16. The Importance of Being a Complement: CED Effects Revisited

    Science.gov (United States)

    Jurka, Johannes

    2010-01-01

    This dissertation revisits subject island effects (Ross 1967, Chomsky 1973) cross-linguistically. Controlled acceptability judgment studies in German, English, Japanese and Serbian show that extraction out of specifiers is consistently degraded compared to extraction out of complements, indicating that the Condition on Extraction domains (CED,…

  17. Databases and information systems: Applications in biogeography

    International Nuclear Information System (INIS)

    Escalante E, Tania; Llorente B, Jorge; Espinoza O, David N; Soberon M, Jorge

    2000-01-01

    Some aspects of the new instrumentalization and methodological elements that make up information systems in biodiversity (ISB) are described. The use of accurate geographically referenced data allows a broad range of available sources: natural history collections and scientific literature require the use of databases and geographic information systems (GIS). The conceptualization of ISB and GIS, based in the use of extensive data bases, has implied detailed modeling and the construction of authoritative archives: exhaustive catalogues of nomenclature and synonymies, complete bibliographic lists, list of names proposed, historical-geographic gazetteers with localities and their synonyms united under a global positioning system which produces a geospheric conception of the earth and its biota. Certain difficulties in the development of the system and the construction of the biological databases are explained: quality control of data, for example. The use of such systems is basic in order to respond to many questions at the frontier of current studies of biodiversity and conservation. In particular, some applications in biogeography and their importance for modeling distributions, to identify and contrast areas of endemism and biological richness for conservation, and their use as tools in what we identify as predictive and experimental faunistics are detailed. Lastly, the process as well as its relevance is emphasized at national and regional levels

  18. Biogeography of Parasitic Nematode Communities in the Galápagos Giant Tortoise: Implications for Conservation Management.

    Directory of Open Access Journals (Sweden)

    Guillaume Fournié

    Full Text Available The Galápagos giant tortoise is an icon of the unique, endemic biodiversity of Galápagos, but little is known of its parasitic fauna. We assessed the diversity of parasitic nematode communities and their spatial distributions within four wild tortoise populations comprising three species across three Galápagos islands, and consider their implication for Galápagos tortoise conservation programmes. Coprological examinations revealed nematode eggs to be common, with more than 80% of tortoises infected within each wild population. Faecal samples from tortoises within captive breeding centres on Santa Cruz, Isabela and San Cristobal islands also were examined. Five different nematode egg types were identified: oxyuroid, ascarid, trichurid and two types of strongyle. Sequencing of the 18S small-subunit ribosomal RNA gene from adult nematodes passed with faeces identified novel sequences indicative of rhabditid and ascaridid species. In the wild, the composition of nematode communities varied according to tortoise species, which co-varied with island, but nematode diversity and abundance were reduced or altered in captive-reared animals. Evolutionary and ecological factors are likely responsible for the variation in nematode distributions in the wild. This possible species/island-parasite co-evolution has not been considered previously for Galápagos tortoises. We recommend that conservation efforts, such as the current Galápagos tortoise captive breeding/rearing and release programme, be managed with respect to parasite biogeography and host-parasite co-evolutionary processes in addition to the biogeography of the host.

  19. Marine biogeography, climate change and societal needs

    Science.gov (United States)

    Krause, Dale C.; Angel, Martin V.

    Pelagic biogeography deals with the large scale distributional patterns of pelagic organisms in the world's oceans, their origins through evolution and the changes in ocean morphology during the geological past, and the factors which currently control and maintain them. The knowledge it generates has a wide variety of uses in science, both basic and applied, and in socio-economics. Its products include: (1) Distributional data compiled in data bases, maps and atlases; (2) Explanatory scientific and non-scientific publications on the distributions and their implications; (3) Standardisation of methodologies; (4) Trained specialists; (5) Advice to society on oceanic aspects of global resource management; and (6) Assessments of oceanic biodiversity in relation to the Biodiversity Convention. The immediate users of this knowledge include oceanographers in other disciplines, ecologists, applied scientists and engineers, resource managers, fishermen, environmentalists, teachers, international lawuers and policy-makers. At present the largest users are the natural resource managers seeking to optimise and to sustain the resource for which they are responsible. There is a considerable body of national and international legislation which is underpinned by biogeographical information. Similarly much of our understanding about past climate which is being used to predict future trends, is based on applying information on present-day distributional patterns to the interpretation of the fossil record in marine sediments. Global change, in the ocean, the atmosphere and on land, is strongly modulated by the feedback between marine organisms, nutrients and greenhouse gases. The marked coherence observed between the distributions of physical, chemical and biological patterns suggest that the process involved in this feedback are linked with pelagic community structure. Remote sensing of sea-surface properties and the heat content of the mixed-layer, offer considerable potential for

  20. Countryside biogeography of Neotropical reptiles and amphibians.

    Science.gov (United States)

    Mendenhall, Chase D; Frishkoff, Luke O; Santos-Barrera, Georgina; Pacheco, Jesús; Mesfun, Eyobed; Mendoza Quijano, Fernando; Ehrlich, Paul R; Ceballos, Gerardo; Daily, Gretchen C; Pringle, Robert M

    2014-04-01

    The future of biodiversity and ecosystem services depends largely on the capacity of human-dominated ecosystems to support them, yet this capacity remains largely unknown. Using the framework of countryside biogeography, and working in the Las Cruces system of Coto Brus, Costa Rica, we assessed reptile and amphibian assemblages within four habitats that typify much of the Neotropics: sun coffee plantations (12 sites), pasture (12 sites), remnant forest elements (12 sites), and a larger, contiguous protected forest (3 sites in one forest). Through analysis of 1678 captures of 67 species, we draw four primary conclusions. First, we found that the majority of reptile (60%) and amphibian (70%) species in this study used an array of habitat types, including coffee plantations and actively grazed pastures. Second, we found that coffee plantations and pastures hosted rich, albeit different and less dense, reptile and amphibian biodiversity relative to the 326-ha Las Cruces Forest Reserve and neighboring forest elements. Third, we found that the small ribbons of "countryside forest elements" weaving through farmland collectively increased the effective size of a 326-ha local forest reserve 16-fold for reptiles and 14-fold for amphibians within our 236-km2 study area. Therefore, countryside forest elements, often too small for most remote sensing techniques to identify, are contributing -95% of the available habitat for forest-dependent reptiles and amphibians in our largely human-dominated study region. Fourth, we found large and pond-reproducing amphibians to prefer human-made habitats, whereas small, stream-reproducing, and directly developing species are more dependent on forest elements. Our investigation demonstrates that tropical farming landscapes can support substantial reptile and amphibian biodiversity. Our approach provides a framework for estimating the conservation value of the complex working landscapes that constitute roughly half of the global land surface

  1. Magnetic islands in tokamaks induced by thermal filamentation

    International Nuclear Information System (INIS)

    Dubois, M.A.; Mohamed-Benkadda, M.S.

    1991-11-01

    The thermal instability of filamentation is revisited in the fully nonlinear regime of a system of cool magnetic island chains, taking into account: the different transport processes inside and outside island cores, and a realistic temperature dependence of radiative losses. This mechanism is found to be a plausible candidate to explain the anomalous electron energy transport

  2. Discrete Biogeography Based Optimization for Feature Selection in Molecular Signatures.

    Science.gov (United States)

    Liu, Bo; Tian, Meihong; Zhang, Chunhua; Li, Xiangtao

    2015-04-01

    Biomarker discovery from high-dimensional data is a complex task in the development of efficient cancer diagnoses and classification. However, these data are usually redundant and noisy, and only a subset of them present distinct profiles for different classes of samples. Thus, selecting high discriminative genes from gene expression data has become increasingly interesting in the field of bioinformatics. In this paper, a discrete biogeography based optimization is proposed to select the good subset of informative gene relevant to the classification. In the proposed algorithm, firstly, the fisher-markov selector is used to choose fixed number of gene data. Secondly, to make biogeography based optimization suitable for the feature selection problem; discrete migration model and discrete mutation model are proposed to balance the exploration and exploitation ability. Then, discrete biogeography based optimization, as we called DBBO, is proposed by integrating discrete migration model and discrete mutation model. Finally, the DBBO method is used for feature selection, and three classifiers are used as the classifier with the 10 fold cross-validation method. In order to show the effective and efficiency of the algorithm, the proposed algorithm is tested on four breast cancer dataset benchmarks. Comparison with genetic algorithm, particle swarm optimization, differential evolution algorithm and hybrid biogeography based optimization, experimental results demonstrate that the proposed method is better or at least comparable with previous method from literature when considering the quality of the solutions obtained. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Biogeography-inspired multiobjective optimization for helping MEMS synthesis

    Directory of Open Access Journals (Sweden)

    Di Barba Paolo

    2017-09-01

    Full Text Available The aim of the paper is to assess the applicability of a multi-objective biogeography-based optimisation algorithm in MEMS synthesis. In order to test the performances of the proposed method in this research field, the optimal shape design of an electrostatic micromotor, and two different electro-thermo-elastic microactuators are considered as the case studies.

  4. Biogeography of tick-borne Bhanja virus (Bunyaviridae) in Europe

    Czech Academy of Sciences Publication Activity Database

    Hubálek, Zdeněk

    2009-01-01

    Roč. 2009, č. 372691 (2009), s. 1-11 ISSN 1687-708X EU Projects: European Commission(XE) 10284 - EDEN Institutional research plan: CEZ:AV0Z60930519 Keywords : Bhanja virus * biogeography * arboviruses Subject RIV: EE - Microbiology, Virology

  5. Influence of summer biogeography on wood warbler stopover abundance

    Science.gov (United States)

    Jeffrey F. Kelly; Rob Smith; Deborah M. Finch; Frank R. Moore; Wang Yong

    1999-01-01

    We evaluated the effect of summer biogeography of migrant wood warblers (Parulidae) on their stopover abundance. To characterize abundance patterns, we used mist-net capture data from spring and fall migration in the Middle Rio Grande Valley, New Mexico, spring migration on the Gulf Coast of Louisiana, and fall migration on the Gulf Coast of Alabama. To describe the...

  6. International Tourists’ Perceived Sustainability of Jeju Island, South Korea

    Directory of Open Access Journals (Sweden)

    Min-Seong Kim

    2017-12-01

    Full Text Available This study investigated the causal relationships between international tourists’ perceived sustainability of Jeju Island, South Korea and environmentally responsible behavior, revisit intention, and positive word-of-mouth communication. Perceived sustainability was employed as a multidimensional construct comprised of economic, cultural, and environmental aspects. Data were collected from international tourists that visited Jeju Island. The results indicated that environmentally responsible behavior was influenced positively by cultural sustainability, and negatively by environmental sustainability. Revisit intention and positive word-of-mouth communication were significantly affected by the three dimensions of sustainability. Based on the findings, associated implications were suggested for sustainable destination management of Jeju Island.

  7. Solving Bi-Objective Optimal Power Flow using Hybrid method of Biogeography-Based Optimization and Differential Evolution Algorithm: A case study of the Algerian Electrical Network

    Directory of Open Access Journals (Sweden)

    Ouafa Herbadji

    2016-03-01

    Full Text Available This paper proposes a new hybrid metaheuristique algorithm based on the hybridization of Biogeography-based optimization with the Differential Evolution for solving the optimal power flow problem with emission control. The biogeography-based optimization (BBO algorithm is strongly influenced by equilibrium theory of island biogeography, mainly through two steps: Migration and Mutation. Differential Evolution (DE is one of the best Evolutionary Algorithms for global optimization. The hybridization of these two methods is used to overcome traps of local optimal solutions and problems of time consumption. The objective of this paper is to minimize the total fuel cost of generation, total emission, total real power loss and also maintain an acceptable system performance in terms of limits on generator real power, bus voltages and power flow of transmission lines. In the present work, BBO/DE has been applied to solve the optimal power flow problems on IEEE 30-bus test system and the Algerian electrical network 114 bus. The results obtained from this method show better performances compared with DE, BBO and other well known metaheuristique and evolutionary optimization methods.

  8. Determinants of orchid species diversity in world islands

    Czech Academy of Sciences Publication Activity Database

    Traxmandlová, Iva; Ackerman, J. D.; Tremblay, R. L.; Roberts, D.L.; Štípková, Zuzana; Kindlmann, Pavel

    2018-01-01

    Roč. 217, č. 1 (2018), s. 12-15 ISSN 0028-646X R&D Projects: GA MŠk(CZ) LO1415; GA ČR GB14-36098G Institutional support: RVO:86652079 Keywords : habitat diversity * island biogeography * latitude * Orchidaceae * species richness * species–area relationship Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 7.330, year: 2016

  9. Taxonomy and Biogeography without frontiers - WhatsApp, Facebook and smartphone digital photography let citizen scientists in more remote localities step out of the dark.

    Science.gov (United States)

    Suprayitno, Nano; Narakusumo, Raden Pramesa; von Rintelen, Thomas; Hendrich, Lars; Balke, Michael

    2017-01-01

    Taxonomy and biogeography can benefit from citizen scientists. The use of social networking and open access cooperative publishing can easily connect naturalists even in more remote areas with in-country scientists and institutions, as well as those abroad. This enables taxonomic efforts without frontiers and at the same time adequate benefit sharing measures. We present new distribution and habitat data for diving beetles of Bali island, Indonesia, as a proof of concept. The species Hydaticus luczonicus Aubé, 1838 and Eretes griseus (Fabricius, 1781) are reported from Bali for the first time. The total number of Dytiscidae species known from Bali is now 34.

  10. Heat Islands

    Science.gov (United States)

    EPA's Heat Island Effect Site provides information on heat islands, their impacts, mitigation strategies, related research, a directory of heat island reduction initiatives in U.S. communities, and EPA's Heat Island Reduction Program.

  11. Life with compass: diversity and biogeography of magnetotactic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wei [Institute of Geology and Geophysics; Bazylinski, Dennis A [Ames Laboratory; Xiao, Tian [Chinese Academy of Sciences; Wu, Long-Fei [v; Pan, Yongxin [Institute of Geology and Geophysics

    2013-11-12

    Magnetotactic bacteria (MTB) are unique in their ability to synthesize intracellular nano-sized minerals of magnetite and/or greigite magnetosomes for magnetic orientation. Thus, they provide an excellent model system to investigate mechanisms of biomineralization. MTB play important roles in bulk sedimentary magnetism and have numerous versatile applications in paleoenvironmental reconstructions, and biotechnological and biomedical fields. Significant progress has been made in recent years in describing the composition of MTB communities and distribution through innovative cultivation-dependent and -independent techniques. In this review, the most recent contributions to the field of diversity and biogeography of MTB are summarized and reviewed. Emphasis is on the novel insights into various factors/processes potentially affecting MTB community distribution. An understanding of the present-day biogeography of MTB, and the ruling parameters of their spatial distribution, will eventually help us predict MTB community shifts with environmental changes and assess their roles in global iron cycling.

  12. Biogeography of photoautotrophs in the high polar biome

    Directory of Open Access Journals (Sweden)

    Stephen Brian Pointing

    2015-09-01

    Full Text Available The global latitudinal gradient in biodiversity weakens in the high polar biome and so an alternative explanation for distribution of Arctic and Antarctic photoautotrophs is required. Here we identify how temporal, microclimate and evolutionary drivers of biogeography are important, rather than the macroclimate features that drive plant diversity patterns elsewhere. High polar ecosystems are biologically unique, with a more central role for bryophytes, lichens and microbial photoautotrophs over that of vascular plants. Constraints on vascular plants arise mainly due to stature and ontogenetic barriers. Conversely non-vascular plant and microbial photoautotroph distribution is correlated with favourable microclimates and the capacity for poikilohydric dormancy. Contemporary distribution also depends on evolutionary history, with adaptive and dispersal traits as well as legacy influencing biogeography. We highlight the relevance of these findings to predicting future impacts on polar plant diversity and to the current status of plants in Arctic and Antarctic conservation policy frameworks.

  13. Biogeography of Iberian freshwater fishes revisited: The roles of historical versus contemporary constraints

    Science.gov (United States)

    Filipe, Ana F.; Araújo, Miguel B.; Doadrio, Ignacio; Angermeier, Paul L.; Collares-Pereira, Maria J.

    2009-01-01

    Aim The question of how much of the shared geographical distribution of biota is due to environmental vs. historical constraints remains unanswered. The aim of this paper is to disentangle the contribution of historical vs. contemporary factors to the distribution of freshwater fish species. In addition, it illustrates how quantifying the contribution of each type of factor improves the classification of biogeographical provinces.

  14. Oxidative phosphorylation revisited

    DEFF Research Database (Denmark)

    Nath, Sunil; Villadsen, John

    2015-01-01

    The fundamentals of oxidative phosphorylation and photophosphorylation are revisited. New experimental data on the involvement of succinate and malate anions respectively in oxidative phosphorylation and photophosphorylation are presented. These new data offer a novel molecular mechanistic...

  15. Biogeography of Puerto Rican ants: a non-equilibrium case?

    Science.gov (United States)

    J.A. Torres; R.R. Snelling

    1997-01-01

    Ants were studied on Puerto Rico and 44 islands surrounding Puerto Rico. Habitat diversity was the best predictor of the number of species per island and the distributions of species followed a nested subset pattern. The number of extinctions per island was low, approximately 1 to 2 extinctions per island in a period of 18 years, and the rates of colonization seem to...

  16. Environmental and Spatial Influences on Biogeography and Community Structure of Benthic Diatoms

    Science.gov (United States)

    Plante, C.; Hill-Spanik, K.; Lowry, J.

    2016-02-01

    Several theoretical and practical reasons suggest that benthic microalgae could be useful bioindicators. For instance, an ideal indicator species or community would be associated with a given habitat due to local physical conditions or biotic interactions (i.e., `environmental filtering'), not due to dispersal limitation. Due to their small size, immense abundances, and reliance on passive dispersal, the popular notion about micro-organisms is that `Everything is everywhere, but, the environment selects' (Baas-Becking 1934). Although much recent research concerning planktonic bacteria and dispersal limitation has been conducted, very little in this regard is known about microeukaryotes, especially benthic microbes. The purpose of our study was to identify and compare spatial and environmental influences on benthic diatom community structure and biogeography. In summer 2015, sediment was sampled at various spatial scales from four barrier island beaches in South Carolina, USA, and high-throughput (Ion Torrent) DNA sequencing was used to characterize diatom assemblages. ANOSIM and principal coordinates analysis revealed that communities were statistically distinct on the four islands. Community dissimilarity was compared to both spatial distance and environmental differences to determine potential influences of these variables on community structure. We found that geographic distance had the strongest correlation with community similarity, with and without one anomalous location, while differences in temperature (air, water, and sediment), nutrients, organic matter, and turbidity also had significant but weaker relationships with community structure. Surprisingly, air temperature, which changes on very short time scales, appeared to be the environmental factor most strongly related to diatom species composition, potentially implicating some unmeasured variable (e.g., cloud cover). However, we also found that temperature and geographic distance were strongly

  17. Out of Borneo: biogeography, phylogeny and divergence date estimates of Artocarpus (Moraceae).

    Science.gov (United States)

    Williams, Evelyn W; Gardner, Elliot M; Harris, Robert; Chaveerach, Arunrat; Pereira, Joan T; Zerega, Nyree J C

    2017-03-01

    speciation may have occurred. By contrast, Artocarpus diversity east of Borneo (where many of the islands have no historical connections to the landmasses of the Sunda and Sahul shelves) is unique and probably the product of over water long-distance dispersal events and subsequent diversification in allopatry. This work represents the most comprehensive Artocarpus phylogeny and biogeography study to date and supports Borneo as an evolutionary biodiversity hotspot. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  18. Benefits to poorly studied taxa of conservation of bird and mammal diversity on islands.

    Science.gov (United States)

    Aslan, Clare; Holmes, Nick; Tershy, Bernie; Spatz, Dena; Croll, Donald A

    2015-02-01

    Protected area delineation and conservation action are urgently needed on marine islands, but the potential biodiversity benefits of these activities can be difficult to assess due to lack of species diversity information for lesser known taxa. We used linear mixed effects modeling and simple spatial analyses to investigate whether conservation activities based on the diversity of well-known insular taxa (birds and mammals) are likely to also capture the diversity of lesser known taxa (reptiles, amphibians, vascular land plants, ants, land snails, butterflies, and tenebrionid beetles). We assembled total, threatened, and endemic diversity data for both well-known and lesser known taxa and combined these with physical island biogeography characteristics for 1190 islands from 109 archipelagos. Among physical island biogeography factors, island area was the best indicator of diversity of both well-known and little-known taxa. Among taxonomic factors, total mammal species richness was the best indicator of total diversity of lesser known taxa, and the combination of threatened mammal and threatened bird diversity was the best indicator of lesser known endemic richness. The results of other intertaxon diversity comparisons were highly variable, however. Based on our results, we suggest that protecting islands above a certain minimum threshold area may be the most efficient use of conservation resources. For example, using our island database, if the threshold were set at 10 km(2) and the smallest 10% of islands greater than this threshold were protected, 119 islands would be protected. The islands would range in size from 10 to 29 km(2) and would include 268 lesser known species endemic to a single island, along with 11 bird and mammal species endemic to a single island. Our results suggest that for islands of equivalent size, prioritization based on total or threatened bird and mammal diversity may also capture opportunities to protect lesser known species endemic to

  19. Floristics and biogeography of vegetation in seasonally dry tropical regions

    DEFF Research Database (Denmark)

    Dexter, K.G.; Smart, B.; Baldauf, C.

    2015-01-01

    To provide an inter-continental overview of the floristics and biogeography of drought-adapted tropical vegetation formations, we compiled a dataset of inventory plots in South America (n=93), Africa (n=84), and Asia (n=92) from savannas (subject to fire), seasonally dry tropical forests (not...... similar vegetation formations (e.g. savannas) are floristically highly dissimilar. Neotropical moist forest, savanna and seasonally dry tropical forest are floristically distinct, but elsewhere there is no clear floristic division of savanna and seasonally dry tropical forest, though moist and dry...... of the ecology, biology and conservation of savannas and seasonally dry tropical forests may be difficult....

  20. Optimization of nonlinear controller with an enhanced biogeography approach

    Directory of Open Access Journals (Sweden)

    Mohammed Salem

    2014-07-01

    Full Text Available This paper is dedicated to the optimization of nonlinear controllers basing of an enhanced Biogeography Based Optimization (BBO approach. Indeed, The BBO is combined to a predator and prey model where several predators are used with introduction of a modified migration operator to increase the diversification along the optimization process so as to avoid local optima and reach the optimal solution quickly. The proposed approach is used in tuning the gains of PID controller for nonlinear systems. Simulations are carried out over a Mass spring damper and an inverted pendulum and has given remarkable results when compared to genetic algorithm and BBO.

  1. Overseas dispersal of Hyperolius reed frogs from Central Africa to the oceanic islands of Sao Tomé and Príncipe

    Czech Academy of Sciences Publication Activity Database

    Bell, R. C.; Drewes, R. C.; Channing, A.; Gvoždík, Václav; Kielgast, J.; Lötters, S.; Stuart, B. L.; Zamudio, K. R.

    2015-01-01

    Roč. 42, č. 1 (2015), s. 65-75 ISSN 0305-0270 Institutional support: RVO:68081766 Keywords : Central Africa * Congo River * Gulf of Guinea * Hyperolius * long -distance dispersal * oceanic island * biogeography * phylogeography * Príncipe * Sao Tomé * species tree Subject RIV: EG - Zoology Impact factor: 3.997, year: 2015

  2. Diversity, relationships, and biogeography of the lambeosaurine dinosaurs from the European Archipelago, with description of the New Aralosaurin Canardia garonnensis.

    Directory of Open Access Journals (Sweden)

    Albert Prieto-Márquez

    Full Text Available We provide a thorough re-evaluation of the taxonomic diversity, phylogenetic relationships, and historical biogeography of the lambeosaurine hadrosaurids from the European Archipelago. Previously published occurrences of European Lambeosaurinae are reviewed and new specimens collected from upper Maastrichtian strata of the south-central Pyrenees are described. No support is found for the recognition of European saurolophines in the available hadrosaurid materials recovered so far from this area. A new genus and species of basal lambeosaurine, Canardia garonnensis, is described on the basis of cranial and appendicular elements collected from upper Maastrichtian strata of southern France. C. garonnensis differs from all other hadrosaurids, except Aralosaurus tuberiferus, in having maxilla with prominent subrectangular rostrodorsal flange; it differs from A. tuberiferus in a few maxillary and prefrontal characters. Together with A. tuberiferus, C. garonnensis integrates the newly recognized tribe Aralosaurini. Inference of lambeosaurine interrelationships via maximum parsimony analysis indicates that the other three known European lambeosaurines are representatives of two additional subclades (tribes of these hadrosaurids: Tsintaosaurini (Pararhabdodon isonensis and Lambeosaurini (the Arenysaurus ardevoli-Blasisaurus canudoi clade. The tribes Aralosaurini, Tsintaosaurini, Lambeosaurini, and Parasaurolophini are formally defined and diagnosed for the first time. Three event-based quantitative methods of ancestral range reconstruction were implemented to infer the historical biogeography of European lambeosaurines: Dispersal-Vicariance Analysis, Bayesian Binary MCMC, and Dispersal-Extinction-Cladogenesis. The results of these analyses, coupled with the absence of pre-Maastrichtian lambeosaurines in the Mesozoic vertebrate fossil record of Europe, favor the hypothesis that aralosaurins and tsintaosaurins were Asian immigrants that reached the Ibero

  3. Phylogeny and Biogeography of Cyanobacteria and Their Produced Toxins

    Directory of Open Access Journals (Sweden)

    Agostinho Antunes

    2013-11-01

    Full Text Available Phylogeny is an evolutionary reconstruction of the past relationships of DNA or protein sequences and it can further be used as a tool to assess population structuring, genetic diversity and biogeographic patterns. In the microbial world, the concept that everything is everywhere is widely accepted. However, it is much debated whether microbes are easily dispersed globally or whether they, like many macro-organisms, have historical biogeographies. Biogeography can be defined as the science that documents the spatial and temporal distribution of a given taxa in the environment at local, regional and continental scales. Speciation, extinction and dispersal are proposed to explain the generation of biogeographic patterns. Cyanobacteria are a diverse group of microorganisms that inhabit a wide range of ecological niches and are well known for their toxic secondary metabolite production. Knowledge of the evolution and dispersal of these microorganisms is still limited, and further research to understand such topics is imperative. Here, we provide a compilation of the most relevant information regarding these issues to better understand the present state of the art as a platform for future studies, and we highlight examples of both phylogenetic and biogeographic studies in non-symbiotic cyanobacteria and cyanotoxins.

  4. Phylogeny and Biogeography of Cyanobacteria and Their Produced Toxins

    Science.gov (United States)

    Moreira, Cristiana; Vasconcelos, Vitor; Antunes, Agostinho

    2013-01-01

    Phylogeny is an evolutionary reconstruction of the past relationships of DNA or protein sequences and it can further be used as a tool to assess population structuring, genetic diversity and biogeographic patterns. In the microbial world, the concept that everything is everywhere is widely accepted. However, it is much debated whether microbes are easily dispersed globally or whether they, like many macro-organisms, have historical biogeographies. Biogeography can be defined as the science that documents the spatial and temporal distribution of a given taxa in the environment at local, regional and continental scales. Speciation, extinction and dispersal are proposed to explain the generation of biogeographic patterns. Cyanobacteria are a diverse group of microorganisms that inhabit a wide range of ecological niches and are well known for their toxic secondary metabolite production. Knowledge of the evolution and dispersal of these microorganisms is still limited, and further research to understand such topics is imperative. Here, we provide a compilation of the most relevant information regarding these issues to better understand the present state of the art as a platform for future studies, and we highlight examples of both phylogenetic and biogeographic studies in non-symbiotic cyanobacteria and cyanotoxins. PMID:24189276

  5. Understanding predicted shifts in diazotroph biogeography using resource competition theory

    Directory of Open Access Journals (Sweden)

    S. Dutkiewicz

    2014-10-01

    Full Text Available We examine the sensitivity of the biogeography of nitrogen fixers to a warming climate and increased aeolian iron deposition in the context of a global earth system model. We employ concepts from the resource-ratio theory to provide a simplifying and transparent interpretation of the results. First we demonstrate that a set of clearly defined, easily diagnosed provinces are consistent with the theory. Using this framework we show that the regions most vulnerable to province shifts and changes in diazotroph biogeography are the equatorial and South Pacific, and central Atlantic. Warmer and dustier climates favor diazotrophs due to an increase in the ratio of supply rate of iron to fixed nitrogen. We suggest that the emergent provinces could be a standard diagnostic for global change models, allowing for rapid and transparent interpretation and comparison of model predictions and the underlying mechanisms. The analysis suggests that monitoring of real world province boundaries, indicated by transitions in surface nutrient concentrations, would provide a clear and easily interpreted indicator of ongoing global change.

  6. Advances and Limitations of Disease Biogeography Using Ecological Niche Modeling.

    Science.gov (United States)

    Escobar, Luis E; Craft, Meggan E

    2016-01-01

    Mapping disease transmission risk is crucial in public and animal health for evidence based decision-making. Ecology and epidemiology are highly related disciplines that may contribute to improvements in mapping disease, which can be used to answer health related questions. Ecological niche modeling is increasingly used for understanding the biogeography of diseases in plants, animals, and humans. However, epidemiological applications of niche modeling approaches for disease mapping can fail to generate robust study designs, producing incomplete or incorrect inferences. This manuscript is an overview of the history and conceptual bases behind ecological niche modeling, specifically as applied to epidemiology and public health; it does not pretend to be an exhaustive and detailed description of ecological niche modeling literature and methods. Instead, this review includes selected state-of-the-science approaches and tools, providing a short guide to designing studies incorporating information on the type and quality of the input data (i.e., occurrences and environmental variables), identification and justification of the extent of the study area, and encourages users to explore and test diverse algorithms for more informed conclusions. We provide a friendly introduction to the field of disease biogeography presenting an updated guide for researchers looking to use ecological niche modeling for disease mapping. We anticipate that ecological niche modeling will soon be a critical tool for epidemiologists aiming to map disease transmission risk, forecast disease distribution under climate change scenarios, and identify landscape factors triggering outbreaks.

  7. Revisiting Okun's Relationship

    NARCIS (Netherlands)

    Dixon, R.; Lim, G.C.; van Ours, Jan

    2016-01-01

    Our paper revisits Okun's relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985-2013. We find that the

  8. Revisiting the Okun relationship

    NARCIS (Netherlands)

    Dixon, R. (Robert); Lim, G.C.; J.C. van Ours (Jan)

    2017-01-01

    textabstractOur article revisits the Okun relationship between observed unemployment rates and output gaps. We include in the relationship the effect of labour market institutions as well as age and gender effects. Our empirical analysis is based on 20 OECD countries over the period 1985–2013. We

  9. Bounded Intention Planning Revisited

    OpenAIRE

    Sievers Silvan; Wehrle Martin; Helmert Malte

    2014-01-01

    Bounded intention planning provides a pruning technique for optimal planning that has been proposed several years ago. In addition partial order reduction techniques based on stubborn sets have recently been investigated for this purpose. In this paper we revisit bounded intention planning in the view of stubborn sets.

  10. A Hydrostatic Paradox Revisited

    Science.gov (United States)

    Ganci, Salvatore

    2012-01-01

    This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

  11. The Faraday effect revisited

    DEFF Research Database (Denmark)

    Cornean, Horia; Nenciu, Gheorghe

    2009-01-01

    This paper is the second in a series revisiting the (effect of) Faraday rotation. We formulate and prove the thermodynamic limit for the transverse electric conductivity of Bloch electrons, as well as for the Verdet constant. The main mathematical tool is a regularized magnetic and geometric...

  12. Predicting community structure in snakes on Eastern Nearctic islands using ecological neutral theory and phylogenetic methods.

    Science.gov (United States)

    Burbrink, Frank T; McKelvy, Alexander D; Pyron, R Alexander; Myers, Edward A

    2015-11-22

    Predicting species presence and richness on islands is important for understanding the origins of communities and how likely it is that species will disperse and resist extinction. The equilibrium theory of island biogeography (ETIB) and, as a simple model of sampling abundances, the unified neutral theory of biodiversity (UNTB), predict that in situations where mainland to island migration is high, species-abundance relationships explain the presence of taxa on islands. Thus, more abundant mainland species should have a higher probability of occurring on adjacent islands. In contrast to UNTB, if certain groups have traits that permit them to disperse to islands better than other taxa, then phylogeny may be more predictive of which taxa will occur on islands. Taking surveys of 54 island snake communities in the Eastern Nearctic along with mainland communities that have abundance data for each species, we use phylogenetic assembly methods and UNTB estimates to predict island communities. Species richness is predicted by island area, whereas turnover from the mainland to island communities is random with respect to phylogeny. Community structure appears to be ecologically neutral and abundance on the mainland is the best predictor of presence on islands. With regard to young and proximate islands, where allopatric or cladogenetic speciation is not a factor, we find that simple neutral models following UNTB and ETIB predict the structure of island communities. © 2015 The Author(s).

  13. Canary Islands

    Science.gov (United States)

    1992-01-01

    This easterly looking view shows the seven major volcanic islands of the Canary Island chain (28.0N, 16.5W) and offers a unique view of the islands that have become a frequent vacation spot for Europeans. The northwest coastline of Africa, (Morocco and Western Sahara), is visible in the background. Frequently, these islands create an impact on local weather (cloud formations) and ocean currents (island wakes) as seen in this photo.

  14. The signature of human pressure history on the biogeography of body mass in tetrapods

    NARCIS (Netherlands)

    Rapacciuolo, Giovanni; Marin, Julie; Costa, Gabriel C.; Helmus, Matthew R.; Behm, Jocelyn E.; Brooks, Thomas M.; Hedges, S. Blair; Radeloff, Volker C.; Young, Bruce E.; Graham, Catherine H.

    2017-01-01

    Aim: Examining the biogeography of body size is crucial for understanding how animal communities are assembled and maintained. In tetrapods, body size varies predictably with temperature, moisture, productivity seasonality and topographical complexity. Although millennial-scale human pressures are

  15. Biodiversity and biogeography pattern of benthic communities in the coastal basins of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sivadas, S.K.; Ingole, B.S.

    Our understanding of coastal biogeography patterns is presently limited to certain regions and marine groups. Comprehending large-scale patterns and their underlying predictors is critical due to the changing environmental conditions. The Indian...

  16. Phylogenetic analyses provide insights into the historical biogeography and evolution of Brachyrhaphis fishes.

    Science.gov (United States)

    Ingley, Spencer J; Reina, Ruth G; Bermingham, Eldredge; Johnson, Jerald B

    2015-08-01

    The livebearing fish genus Brachyrhaphis (Poeciliidae) has become an increasingly important model in evolution and ecology research, yet the phylogeny of this group is not well understood, nor has it been examined thoroughly using modern phylogenetic methods. Here, we present the first comprehensive phylogenetic analysis of Brachyrhaphis by using four molecular markers (3mtDNA, 1nucDNA) to infer relationships among species in this genus. We tested the validity of this genus as a monophyletic group using extensive outgroup sampling based on recent phylogenetic hypotheses of Poeciliidae. We also tested the validity of recently described species of Brachyrhaphis that are part of the B. episcopi complex in Panama. Finally, we examined the impact of historical events on diversification of Brachyrhaphis, and made predictions regarding the role of different ecological environments on evolutionary diversification where known historical events apparently fail to explain speciation. Based on our results, we reject the monophyly of Brachyrhaphis, and question the validity of two recently described species (B. hessfeldi and B. roswithae). Historical biogeography of Brachyrhaphis generally agrees with patterns found in other freshwater taxa in Lower Central America, which show that geological barriers frequently predict speciation. Specifically, we find evidence in support of an 'island' model of Lower Central American formation, which posits that the nascent isthmus was partitioned by several marine connections before linking North and South America. In some cases where historic events (e.g., vicariance) fail to explain allopatric species breaks in Brachyrhaphis, ecological processes (e.g., divergent predation environments) offer additional insight into our understanding of phylogenetic diversification in this group. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Biogeography and change among regional coral communities across the Western Indian Ocean.

    Directory of Open Access Journals (Sweden)

    Timothy R McClanahan

    Full Text Available Coral reefs are biodiverse ecosystems structured by abiotic and biotic factors operating across many spatial scales. Regional-scale interactions between climate change, biogeography and fisheries management remain poorly understood. Here, we evaluated large-scale patterns of coral communities in the western Indian Ocean after a major coral bleaching event in 1998. We surveyed 291 coral reef sites in 11 countries and over 30° of latitude between 2004 and 2011 to evaluate variations in coral communities post 1998 across gradients in latitude, mainland-island geography and fisheries management. We used linear mixed-effect hierarchical models to assess total coral cover, the abundance of four major coral families (acroporids, faviids, pocilloporids and poritiids, coral genus richness and diversity, and the bleaching susceptibility of the coral communities. We found strong latitudinal and geographic gradients in coral community structure and composition that supports the presence of a high coral cover and diversity area that harbours temperature-sensitive taxa in the northern Mozambique Channel between Tanzania, northern Mozambique and northern Madagascar. Coral communities in the more northern latitudes of Kenya, Seychelles and the Maldives were generally composed of fewer bleaching-tolerant coral taxa and with reduced richness and diversity. There was also evidence for continued declines in the abundance of temperature-sensitive taxa and community change after 2004. While there are limitations of our regional dataset in terms of spatial and temporal replication, these patterns suggest that large-scale interactions between biogeographic factors and strong temperature anomalies influence coral communities while smaller-scale factors, such as the effect of fisheries closures, were weak. The northern Mozambique Channel, while not immune to temperature disturbances, shows continued signs of resistance to climate disturbances and remains a priority for

  18. 'Felson Signs' revisited

    International Nuclear Information System (INIS)

    George, Phiji P.; Irodi, Aparna; Keshava, Shyamkumar N.; Lamont, Anthony C.

    2014-01-01

    In this article we revisit, with the help of images, those classic signs in chest radiography described by Dr Benjamin Felson himself, or other illustrious radiologists of his time, cited and discussed in 'Chest Roentgenology'. We briefly describe the causes of the signs, their utility and the differential diagnosis to be considered when each sign is seen. Wherever possible, we use CT images to illustrate the basis of some of these classic radiographic signs.

  19. Time functions revisited

    Science.gov (United States)

    Fathi, Albert

    2015-07-01

    In this paper we revisit our joint work with Antonio Siconolfi on time functions. We will give a brief introduction to the subject. We will then show how to construct a Lipschitz time function in a simplified setting. We will end with a new result showing that the Aubry set is not an artifact of our proof of existence of time functions for stably causal manifolds.

  20. Seven Issues, Revisited

    OpenAIRE

    Whitehead, Jim; De Bra, Paul; Grønbæk, Kaj; Larsen, Deena; Legget, John; schraefel, monica m.c.

    2002-01-01

    It has been 15 years since the original presentation by Frank Halasz at Hypertext'87 on seven issues for the next generation of hypertext systems. These issues are: Search and Query Composites Virtual Structures Computation in/over hypertext network Versioning Collaborative Work Extensibility and Tailorability Since that time, these issues have formed the nucleus of multiple research agendas within the Hypertext community. Befitting this direction-setting role, the issues have been revisited ...

  1. Deterministic Graphical Games Revisited

    DEFF Research Database (Denmark)

    Andersson, Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro

    2008-01-01

    We revisit the deterministic graphical games of Washburn. A deterministic graphical game can be described as a simple stochastic game (a notion due to Anne Condon), except that we allow arbitrary real payoffs but disallow moves of chance. We study the complexity of solving deterministic graphical...... games and obtain an almost-linear time comparison-based algorithm for computing an equilibrium of such a game. The existence of a linear time comparison-based algorithm remains an open problem....

  2. Architectural design drives the biogeography of indoor bacterial communities.

    Science.gov (United States)

    Kembel, Steven W; Meadow, James F; O'Connor, Timothy K; Mhuireach, Gwynne; Northcutt, Dale; Kline, Jeff; Moriyama, Maxwell; Brown, G Z; Bohannan, Brendan J M; Green, Jessica L

    2014-01-01

    Architectural design has the potential to influence the microbiology of the built environment, with implications for human health and well-being, but the impact of design on the microbial biogeography of buildings remains poorly understood. In this study we combined microbiological data with information on the function, form, and organization of spaces from a classroom and office building to understand how design choices influence the biogeography of the built environment microbiome. Sequencing of the bacterial 16S gene from dust samples revealed that indoor bacterial communities were extremely diverse, containing more than 32,750 OTUs (operational taxonomic units, 97% sequence similarity cutoff), but most communities were dominated by Proteobacteria, Firmicutes, and Deinococci. Architectural design characteristics related to space type, building arrangement, human use and movement, and ventilation source had a large influence on the structure of bacterial communities. Restrooms contained bacterial communities that were highly distinct from all other rooms, and spaces with high human occupant diversity and a high degree of connectedness to other spaces via ventilation or human movement contained a distinct set of bacterial taxa when compared to spaces with low occupant diversity and low connectedness. Within offices, the source of ventilation air had the greatest effect on bacterial community structure. Our study indicates that humans have a guiding impact on the microbial biodiversity in buildings, both indirectly through the effects of architectural design on microbial community structure, and more directly through the effects of human occupancy and use patterns on the microbes found in different spaces and space types. The impact of design decisions in structuring the indoor microbiome offers the possibility to use ecological knowledge to shape our buildings in a way that will select for an indoor microbiome that promotes our health and well-being.

  3. Novel Methods in Disease Biogeography: A Case Study with Heterosporosis

    Directory of Open Access Journals (Sweden)

    Luis E. Escobar

    2017-07-01

    Full Text Available Disease biogeography is currently a promising field to complement epidemiology, and ecological niche modeling theory and methods are a key component. Therefore, applying the concepts and tools from ecological niche modeling to disease biogeography and epidemiology will provide biologically sound and analytically robust descriptive and predictive analyses of disease distributions. As a case study, we explored the ecologically important fish disease Heterosporosis, a relatively poorly understood disease caused by the intracellular microsporidian parasite Heterosporis sutherlandae. We explored two novel ecological niche modeling methods, the minimum-volume ellipsoid (MVE and the Marble algorithm, which were used to reconstruct the fundamental and the realized ecological niche of H. sutherlandae, respectively. Additionally, we assessed how the management of occurrence reports can impact the output of the models. Ecological niche models were able to reconstruct a proxy of the fundamental and realized niche for this aquatic parasite, identifying specific areas suitable for Heterosporosis. We found that the conceptual and methodological advances in ecological niche modeling provide accessible tools to update the current practices of spatial epidemiology. However, careful data curation and a detailed understanding of the algorithm employed are critical for a clear definition of the assumptions implicit in the modeling process and to ensure biologically sound forecasts. In this paper, we show how sensitive MVE is to the input data, while Marble algorithm may provide detailed forecasts with a minimum of parameters. We showed that exploring algorithms of different natures such as environmental clusters, climatic envelopes, and logistic regressions (e.g., Marble, MVE, and Maxent provide different scenarios of potential distribution. Thus, no single algorithm should be used for disease mapping. Instead, different algorithms should be employed for a more

  4. Vestindien Revisited: I kølvandet på kuldampere og cruiseturister

    DEFF Research Database (Denmark)

    Brichet, Nathalia Sofie; Hastrup, Frida; Ørstedholm, Maroe

    2017-01-01

    What traces did Denmark officially leave behind when the West Indies were sold to the United States in 1917? And how are the islands still affected today by Denmark’s presence on the islands? The M/S Maritime Museum tries to answer these questions in its special new exhibition, ‘U.S. VIRGIN ISLAN...... special exhibition “U.S. VIRGIN ISLANDS REVISITED – in the wake of colliers and cruise tourists,” to commemorate the centennial anniversary of selling the West Indies to the United States of America....

  5. Biogeography and molar morphology of Pleistocene African elephants: new evidence from Elandsfontein, Western Cape Province, South Africa

    Science.gov (United States)

    Smith, Kathlyn M.; Stynder, Deano D.

    2015-05-01

    Elandsfontein (EFT) is a Middle Pleistocene archaeological/paleontological site located in the Western Cape Province of South Africa. The largest herbivore in the assemblage is Loxodonta atlantica zulu, an extinct member of the genus that includes modern African elephants. No Elephas recki specimens were recovered at EFT, despite their common occurrence in other regions of Africa at the same time. Because E. recki and L. atlantica molars are similar in appearance, but the two species are traditionally viewed as dominating different regions of Africa during the Pleistocene, isolated molars may on occasions have been assessed to species level on the basis of geography rather than morphology. The last morphologic evaluation of EFT elephants was conducted in the 1970s, and revisiting this issue with new specimens provides added insight into the evolution of elephants in Africa. Reevaluating morphological characteristics of EFT elephant molars, through qualitative and quantitative description and comparison with Middle Pleistocene E. recki recki, L. atlantica atlantica, and L. atlantica zulu molar morphology, corroborates assessment of EFT elephants as L. a. zulu. Two recently discovered, previously undescribed molars from EFT show that molars of L. a. zulu exhibit greater variation in enamel thickness, lamellar frequency, and occlusal surface morphology than previously reported. An update of the Pleistocene biogeography of Loxodonta and Elephas indicates that fossil remains of both are often found at the same localities in eastern Africa. Their rare co-occurrences in the north and south, however, suggest geographic separation of the two genera in at least some regions of Africa, which may have been based on habitat preference.

  6. Diversification in a fluctuating island setting: rapid radiation of Ohomopterus ground beetles in the Japanese Islands.

    Science.gov (United States)

    Sota, Teiji; Nagata, Nobuaki

    2008-10-27

    The Japanese Islands have been largely isolated from the East Asian mainland since the Early Pleistocene, allowing the diversification of endemic lineages. Here, we explore speciation rates and historical biogeography of the ground beetles of the subgenus Ohomopterus (genus Carabus) based on nuclear and mitochondrial gene sequences. Ohomopterus diverged into 15 species during the Pleistocene. The speciation rate was 1.92 Ma(-1) and was particularly fast (2.37 Ma(-1)) in a group with highly divergent genitalia. Speciation occurred almost solely within Honshu, the largest island with complex geography. Species diversity is highest in central Honshu, where closely related species occur parapatrically and different-sized species co-occur. Range expansion of some species in the past has resulted in such species assemblages. Introgressive hybridization, at least for mitochondrial DNA, has occurred repeatedly between species in contact, but has not greatly disturbed species distinctness. Small-island populations of some species were separated from main-island populations only after the last glacial (or the last interglacial) period, indicating that island isolation had little role in speciation. Thus, the speciation and formation of the Ohomopterus assemblage occurred despite frequent opportunities for secondary contact and hybridization and the lack of persistent isolation. This radiation was achieved without substantial ecological differentiation, but with marked differentiation in mechanical agents of reproductive isolation (body size and genital morphology).

  7. Biogeography and diversity of pines in the Madrean Archipelago

    Science.gov (United States)

    George M. Ferguson; Aaron D. Flesch; Thomas R. Van Devender

    2013-01-01

    Pines are important dominants in pine-oak, pine and mixed-conifer forests across the Colorado Plateau, southern Rocky Mountains, Sierra Madre Occidental, and in the intervening Sky Islands of the United States-Mexico borderlands. All 17 native species of pines in the Sky Islands region or their adjacent mountain mainlands reach the northern or southern margins of their...

  8. Deterministic Graphical Games Revisited

    DEFF Research Database (Denmark)

    Andersson, Klas Olof Daniel; Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro

    2012-01-01

    Starting from Zermelo’s classical formal treatment of chess, we trace through history the analysis of two-player win/lose/draw games with perfect information and potentially infinite play. Such chess-like games have appeared in many different research communities, and methods for solving them......, such as retrograde analysis, have been rediscovered independently. We then revisit Washburn’s deterministic graphical games (DGGs), a natural generalization of chess-like games to arbitrary zero-sum payoffs. We study the complexity of solving DGGs and obtain an almost-linear time comparison-based algorithm...

  9. Bottomonium spectrum revisited

    CERN Document Server

    Segovia, Jorge; Entem, David R.; Fernández, Francisco

    2016-01-01

    We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about the better way to determine their properties experimentally.

  10. Metamorphosis in Craniiformea revisited

    DEFF Research Database (Denmark)

    Altenburger, Andreas; Wanninger, Andreas; Holmer, Lars E.

    2013-01-01

    We revisited the brachiopod fold hypothesis and investigated metamorphosis in the craniiform brachiopod Novocrania anomala. Larval development is lecithotrophic and the dorsal (brachial) valve is secreted by dorsal epithelia. We found that the juvenile ventral valve, which consists only of a thin...... brachiopods during metamorphosis to cement their pedicle to the substrate. N. anomala is therefore not initially attached by a valve but by material corresponding to pedicle cuticle. This is different to previous descriptions, which had led to speculations about a folding event in the evolution of Brachiopoda...

  11. Saint Lucia revisited.

    Science.gov (United States)

    Bos, R; Février, M; Knudsen, A B

    1988-10-01

    The eastern Caribbean island of Saint Lucia is now famous in parasitological history as the setting for a major programme of schistosomiasis control'. Perhaps less well-known are the island's effective control of many intestinal parasites, and elimination of malaria, such that the current patterns of mortality and other demographic indicators now resemble those of industrialized countries. More recently, the island has become the focus for another community-based health programme as the Caribbean region again comes to grips with Aedes aegypti and its recently imported relative, Aedes albopictus, important vectors of yellow fever and dengue viruses (see Box 1).

  12. Equilibrium Bird Species Diversity in Atlantic Islands.

    Science.gov (United States)

    Valente, Luis; Illera, Juan Carlos; Havenstein, Katja; Pallien, Tamara; Etienne, Rampal S; Tiedemann, Ralph

    2017-06-05

    Half a century ago, MacArthur and Wilson proposed that the number of species on islands tends toward a dynamic equilibrium diversity around which species richness fluctuates [1]. The current prevailing view in island biogeography accepts the fundamentals of MacArthur and Wilson's theory [2] but questions whether their prediction of equilibrium can be fulfilled over evolutionary timescales, given the unpredictable and ever-changing nature of island geological and biotic features [3-7]. Here we conduct a complete molecular phylogenetic survey of the terrestrial bird species from four oceanic archipelagos that make up the diverse Macaronesian bioregion-the Azores, the Canary Islands, Cape Verde, and Madeira [8, 9]. We estimate the times at which birds colonized and speciated in the four archipelagos, including many previously unsampled endemic and non-endemic taxa and their closest continental relatives. We develop and fit a new multi-archipelago dynamic stochastic model to these data, explicitly incorporating information from 91 taxa, both extant and extinct. Remarkably, we find that all four archipelagos have independently achieved and maintained a dynamic equilibrium over millions of years. Biogeographical rates are homogeneous across archipelagos, except for the Canary Islands, which exhibit higher speciation and colonization. Our finding that the avian communities of the four Macaronesian archipelagos display an equilibrium diversity pattern indicates that a diversity plateau may be rapidly achieved on islands where rates of in situ radiation are low and extinction is high. This study reveals that equilibrium processes may be more prevalent than recently proposed, supporting MacArthur and Wilson's 50-year-old theory. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Revisiting Nursing Research in Nigeria

    African Journals Online (AJOL)

    2016-08-18

    Aug 18, 2016 ... health care research, it is therefore pertinent to revisit the state of nursing research in the country. .... platforms, updated libraries with electronic resource ... benchmarks for developing countries of 26%, [17] the amount is still ...

  14. Rice Blast Control and Polyvarietal Planting in the Philippines: A Study in Genotype by Environment Biogeography

    Directory of Open Access Journals (Sweden)

    Daniel J. Falvo

    2001-06-01

    Full Text Available Current approaches to biogeography are based on organismic biology. Certain biogeographical phenomena, however, cannot be fully understood using organismic approaches to biogeography. I employed an approach based on molecular biology and biochemistry that I call genotype by environment biogeography in order to provide a more complete understanding of why the dispersal of rice blast disease is less efficient in fields planted with mixtures of rice varieties. In a case study of an upland ricefield in the Philippines, I found that planting varietal mixtures results in a form of effective blast control that I call intrafield gene deployment. I suggest that intrafield gene deployment be used to design more effective methods of blast control in intensive rice agriculture.

  15. Marshall Islands

    OpenAIRE

    World Bank

    2015-01-01

    This note aims to build understanding of the existing disaster risk financing and insurance (DRFI) tools in use in The Marshall Islands and to identify gaps where potential engagement could further develop financial resilience. The likelihood that a hazardous event will have a significant impact on the Marshall Islands has risen with the increasing levels of population and assets in the urban ...

  16. How the Aridification of Australia Structured the Biogeography and Influenced the Diversification of a Large Lineage of Australian Cicadas.

    Science.gov (United States)

    Owen, Christopher L; Marshall, David C; Hill, Kathy B R; Simon, Chris

    2017-07-01

    diversified and continue to reside on mesic hosts in isolated "habitat islands". Future work should focus on groups of similar ages with similar distribution patterns to determine whether this tempo and pattern of diversification and biogeography is consistent with evidence from other phytophagous insects. © The Author(s) 2017. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Clipperton Atoll (eastern Pacific): oceanography, geomorphology, reef-building coral ecology and biogeography

    Science.gov (United States)

    Glynn, P. W.; Veron, J. E. N.; Wellington, G. M.

    1996-06-01

    Coral reef geomorphology and community composition were investigated in the tropical northeastern Pacific during April 1994. Three areas were surveyed in the Revillagigedo Islands (Mexico), and an intensive study was conducted on Clipperton Atoll (1,300 km SW of Acapulco), including macro-scale surface circulation, sea surface temperature (SST) climatology, geomorphology, coral community structure, zonation, and biogeography. Satellite-tracked drifter buoys from 1979 1993 demonstrated complex patterns of surface circulation with dominantly easterly flow (North Equatorial Counter Current, NECC), but also westerly currents (South Equatorial Current, SEC) that could transport propagules to Clipperton from both central and eastern Pacific regions. The northernmost latitude reached by the NECC is not influenced by El Niño-Southern Oscillation (ENSO) events, but easterly flow velocity evidently is accelerated at such times. Maximum NECC flow rates indicate that the eastern Pacific barrier can be bridged in 60 to 120 days. SST anomalies at Clipperton occur during ENSO events and were greater at Clipperton in 1987 than during 1982 1983. Shallow (15 18 m)and deep (50 58 m) terraces are present around most of Clipperton, probably representing Modern and late Pleistocene sea level stands. Although Clipperton is a well developed atoll with high coral cover, the reef-building fauna is depauperate, consisting of only 7 species of scleractinian corals belonging to the genera Pocillopora, Porites, Pavona and Leptoseris, and 1 species of hydrocoral in the genus Millepora. The identities of the one Pocilpopora species and one of the two Porites species are still unknown. Two of the remaining scleractinians ( Pavona minuta, Leptoseris scabra) and the hydrocoral ( Millepora exaesa), all formerly known from central and western Pacific localities, represent new eastern Pacific records. Scleractinian corals predominate (10 100% cover) over insular shelf depths of 8 to 60m, and crustose

  18. Life quality index revisited

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager

    2004-01-01

    The derivation of the life quality index (LQI) is revisited for a revision. This revision takes into account the unpaid but necessary work time needed to stay alive in clean and healthy conditions to be fit for effective wealth producing work and to enjoyable free time. Dimension analysis...... at birth should not vary between countries. Finally the distributional assumptions are relaxed as compared to the assumptions made in an earlier work by the author. These assumptions concern the calculation of the life expectancy change due to the removal of an accident source. Moreover a simple public...... consistency problems with the standard power function expression of the LQI are pointed out. It is emphasized that the combination coefficient in the convex differential combination between the relative differential of the gross domestic product per capita and the relative differential of the expected life...

  19. Quantum duel revisited

    International Nuclear Information System (INIS)

    Schmidt, Alexandre G M; Paiva, Milena M

    2012-01-01

    We revisit the quantum two-person duel. In this problem, both Alice and Bob each possess a spin-1/2 particle which models dead and alive states for each player. We review the Abbott and Flitney result—now considering non-zero α 1 and α 2 in order to decide if it is better for Alice to shoot or not the second time—and we also consider a duel where players do not necessarily start alive. This simple assumption allows us to explore several interesting special cases, namely how a dead player can win the duel shooting just once, or how can Bob revive Alice after one shot, and the better strategy for Alice—being either alive or in a superposition of alive and dead states—fighting a dead opponent. (paper)

  20. Satellite failures revisited

    Science.gov (United States)

    Balcerak, Ernie

    2012-12-01

    In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

  1. Logistics Innovation Process Revisited

    DEFF Research Database (Denmark)

    Gammelgaard, Britta; Su, Shong-Iee Ivan; Yang, Su-Lan

    2011-01-01

    Purpose – The purpose of this paper is to learn more about logistics innovation processes and their implications for the focal organization as well as the supply chain, especially suppliers. Design/methodology/approach – The empirical basis of the study is a longitudinal action research project...... that was triggered by the practical needs of new ways of handling material flows of a hospital. This approach made it possible to revisit theory on logistics innovation process. Findings – Apart from the tangible benefits reported to the case hospital, five findings can be extracted from this study: the logistics...... innovation process model may include not just customers but also suppliers; logistics innovation in buyer-supplier relations may serve as an alternative to outsourcing; logistics innovation processes are dynamic and may improve supplier partnerships; logistics innovations in the supply chain are as dependent...

  2. Klein's double discontinuity revisited

    DEFF Research Database (Denmark)

    Winsløw, Carl; Grønbæk, Niels

    2014-01-01

    Much effort and research has been invested into understanding and bridging the ‘gaps’ which many students experience in terms of contents and expectations as they begin university studies with a heavy component of mathematics, typically in the form of calculus courses. We have several studies...... of bridging measures, success rates and many other aspects of these “entrance transition” problems. In this paper, we consider the inverse transition, experienced by university students as they revisit core parts of high school mathematics (in particular, calculus) after completing the undergraduate...... mathematics courses which are mandatory to become a high school teacher of mathematics. To what extent does the “advanced” experience enable them to approach the high school calculus in a deeper and more autonomous way ? To what extent can “capstone” courses support such an approach ? How could it be hindered...

  3. Reframing in dentistry: Revisited

    Directory of Open Access Journals (Sweden)

    Sivakumar Nuvvula

    2013-01-01

    Full Text Available The successful practice of dentistry involves a good combination of technical skills and soft skills. Soft skills or communication skills are not taught extensively in dental schools and it can be challenging to learn and at times in treating dental patients. Guiding the child′s behavior in the dental operatory is one of the preliminary steps to be taken by the pediatric dentist and one who can successfully modify the behavior can definitely pave the way for a life time comprehensive oral care. This article is an attempt to revisit a simple behavior guidance technique, reframing and explain the possible psychological perspectives behind it for better use in the clinical practice.

  4. Geographical, Temporal and Environmental Determinants of Bryophyte Species Richness in the Macaronesian Islands

    Science.gov (United States)

    Aranda, Silvia C.; Gabriel, Rosalina; Borges, Paulo A. V.; Santos, Ana M. C.; de Azevedo, Eduardo Brito; Patiño, Jairo; Hortal, Joaquín; Lobo, Jorge M.

    2014-01-01

    Species richness on oceanic islands has been related to a series of ecological factors including island size and isolation (i.e. the Equilibrium Model of Island Biogeography, EMIB), habitat diversity, climate (i.e., temperature and precipitation) and more recently island ontogeny (i.e. the General Dynamic Model of oceanic island biogeography, GDM). Here we evaluate the relationship of these factors with the diversity of bryophytes in the Macaronesian region (Azores, Madeira, Canary Islands and Cape Verde). The predictive power of EMIB, habitat diversity, climate and the GDM on total bryophyte richness, as well as moss and liverwort richness (the two dominant bryophyte groups), was evaluated through ordinary least squares regressions. After choosing the best subset of variables using inference statistics, we used partial regression analyses to identify the independent and shared effects of each model. The variables included within each model were similar for mosses and liverworts, with orographic mist layer being one of the most important predictors of richness. Models combining climate with either the GDM or habitat diversity explained most of richness variation (up to 91%). There was a high portion of shared variance between all pairwise combinations of factors in mosses, while in liverworts around half of the variability in species richness was accounted for exclusively by climate. Our results suggest that the effects of climate and habitat are strong and prevalent in this region, while geographical factors have limited influence on Macaronesian bryophyte diversity. Although climate is of great importance for liverwort richness, in mosses its effect is similar to or, at least, indiscernible from the effect of habitat diversity and, strikingly, the effect of island ontogeny. These results indicate that for highly vagile taxa on oceanic islands, the dispersal process may be less important for successful colonization than the availability of suitable ecological

  5. Phylogeny and biogeography of North-American wild rice (Zizania L.Poaceae)

    Science.gov (United States)

    The wild-rice genus Zizania includes four species disjunctly distributed in eastern Asia and North America, with three species (Z. aquatica, Z. palustris, and Z. texana) in North America and one (Z. latifolia) in eastern Asia. The phylogeny and biogeography of Zizania were explored using sequences o...

  6. Widespread green algae Chlorella and Stichococcus exhibit polar-temperate and tropical-temperate biogeography

    Czech Academy of Sciences Publication Activity Database

    Hodač, L.; Hallmann, Ch.; Spitzer, K.; Elster, Josef; Fasshauer, F.; Brinkmann, N.; Lepka, D.; Diwan, V.; Friedl, T.

    2016-01-01

    Roč. 92, č. 8 (2016), s. 1-16, č. článku fiw122. ISSN 0168-6496 Institutional support: RVO:67985939 Keywords : Chlorella * Stichococcus * biogeography Subject RIV: EH - Ecology, Behaviour Impact factor: 3.720, year: 2016

  7. The Unified Neutral Theory of Biodiversity and Biogeography at Age Ten

    NARCIS (Netherlands)

    Rosindell, James; Hubbell, Stephen P.; Etienne, Rampal S.

    A decade has now passed since Hubbell published The Unified Neutral Theory of Biodiversity and Biogeography. Neutral theory highlights the importance of dispersal limitation, speciation and ecological drift in the natural world and provides quantitative null models for assessing the role of

  8. 'Everything is everywhere: but the environment selects': ubiquitous distribution and ecological determinism in microbial biogeography.

    Science.gov (United States)

    O'Malley, Maureen A

    2008-09-01

    Recent discoveries of geographical patterns in microbial distribution are undermining microbiology's exclusively ecological explanations of biogeography and their fundamental assumption that 'everything is everywhere: but the environment selects'. This statement was generally promulgated by Dutch microbiologist Martinus Wilhelm Beijerinck early in the twentieth century and specifically articulated in 1934 by his compatriot, Lourens G. M. Baas Becking. The persistence of this precept throughout twentieth-century microbiology raises a number of issues in relation to its formulation and widespread acceptance. This paper will trace the conceptual history of Beijerinck's claim that 'everything is everywhere' in relation to a more general account of its theoretical, experimental and institutional context. His principle also needs to be situated in relationship to plant and animal biogeography, which, this paper will argue, forms a continuum of thought with microbial biogeography. Finally, a brief overview of the contemporary microbiological research challenging 'everything is everywhere' reveals that philosophical issues from Beijerinck's era of microbiology still provoke intense discussion in twenty-first century investigations of microbial biogeography.

  9. Tracking trails by cracking codes : Molecular biogeography and evolution of benthic cold-water seaweeds

    NARCIS (Netherlands)

    van Oppen, Madeleine Josephine Henriette

    1995-01-01

    The main objective of this thesis was to examine the evolutionary diversification and biogeography of some polar and cold-temperatsee aweeds. Distribution patterns and dispersal routes were investigated in three species exhibiting a bipolar disjunction and one with an amphi-Atlantic distribution, by

  10. Pholcid spider molecular systematics revisited, with new insights into the biogeography and the evolution of the group

    DEFF Research Database (Denmark)

    Dimitrov, Dimitar Stefanov; Astrin, Jonas J.; Huber, Bernhard A.

    2013-01-01

    analysed using parsimony, maximum-likelihood and Bayesian methods for phylogenetic reconstruction. We show that in several previously problematic cases molecular and morphological data are converging towards a single hypothesis. This is also the first study that explicitly addresses the age of pholcid......We analysed seven genetic markers sampled from 165 pholcids and 34 outgroups in order to test and improve the recently revised classification of the family. Our results are based on the largest and most comprehensive set of molecular data so far to study pholcid relationships. The data were...

  11. Extinction and recolonization of maritime Antarctica in the limpet Nacella concinna (Strebel, 1908) during the last glacial cycle: toward a model of Quaternary biogeography in shallow Antarctic invertebrates.

    Science.gov (United States)

    González-Wevar, C A; Saucède, T; Morley, S A; Chown, S L; Poulin, E

    2013-10-01

    Quaternary glaciations in Antarctica drastically modified geographical ranges and population sizes of marine benthic invertebrates and thus affected the amount and distribution of intraspecific genetic variation. Here, we present new genetic information in the Antarctic limpet Nacella concinna, a dominant Antarctic benthic species along shallow ice-free rocky ecosystems. We examined the patterns of genetic diversity and structure in this broadcast spawner along maritime Antarctica and from the peri-Antarctic island of South Georgia. Genetic analyses showed that N. concinna represents a single panmictic unit in maritime Antarctic. Low levels of genetic diversity characterized this population; its median-joining haplotype network revealed a typical star-like topology with a short genealogy and a dominant haplotype broadly distributed. As previously reported with nuclear markers, we detected significant genetic differentiation between South Georgia Island and maritime Antarctica populations. Higher levels of genetic diversity, a more expanded genealogy and the presence of more private haplotypes support the hypothesis of glacial persistence in this peri-Antarctic island. Bayesian Skyline plot and mismatch distribution analyses recognized an older demographic history in South Georgia. Approximate Bayesian computations did not support the persistence of N. concinna along maritime Antarctica during the last glacial period, but indicated the resilience of the species in peri-Antarctic refugia (South Georgia Island). We proposed a model of Quaternary Biogeography for Antarctic marine benthic invertebrates with shallow and narrow bathymetric ranges including (i) extinction of maritime Antarctic populations during glacial periods; (ii) persistence of populations in peri-Antarctic refugia; and (iii) recolonization of maritime Antarctica following the deglaciation process. © 2013 John Wiley & Sons Ltd.

  12. Climate-driven changes in functional biogeography of Arctic marine fish communities.

    Science.gov (United States)

    Frainer, André; Primicerio, Raul; Kortsch, Susanne; Aune, Magnus; Dolgov, Andrey V; Fossheim, Maria; Aschan, Michaela M

    2017-11-14

    Climate change triggers poleward shifts in species distribution leading to changes in biogeography. In the marine environment, fish respond quickly to warming, causing community-wide reorganizations, which result in profound changes in ecosystem functioning. Functional biogeography provides a framework to address how ecosystem functioning may be affected by climate change over large spatial scales. However, there are few studies on functional biogeography in the marine environment, and none in the Arctic, where climate-driven changes are most rapid and extensive. We investigated the impact of climate warming on the functional biogeography of the Barents Sea, which is characterized by a sharp zoogeographic divide separating boreal from Arctic species. Our unique dataset covered 52 fish species, 15 functional traits, and 3,660 stations sampled during the recent warming period. We found that the functional traits characterizing Arctic fish communities, mainly composed of small-sized bottom-dwelling benthivores, are being rapidly replaced by traits of incoming boreal species, particularly the larger, longer lived, and more piscivorous species. The changes in functional traits detected in the Arctic can be predicted based on the characteristics of species expected to undergo quick poleward shifts in response to warming. These are the large, generalist, motile species, such as cod and haddock. We show how functional biogeography can provide important insights into the relationship between species composition, diversity, ecosystem functioning, and environmental drivers. This represents invaluable knowledge in a period when communities and ecosystems experience rapid climate-driven changes across biogeographical regions. Copyright © 2017 the Author(s). Published by PNAS.

  13. Molecular biogeography of Europe: Pleistocene cycles and postglacial trends

    Directory of Open Access Journals (Sweden)

    Schmitt Thomas

    2007-04-01

    Full Text Available Abstract The climatic cycles with subsequent glacial and intergalcial periods have had a great impact on the distribution and evolution of species. Using genetic analytical tools considerably increased our understanding of these processes. In this review I therefore give an overview of the molecular biogeography of Europe. For means of simplification, I distinguish between three major biogeographical entities: (i "Mediterranean" with Mediterranean differentiation and dispersal centres, (ii "Continental" with extra-Mediterranean centres and (iii "Alpine" and/or "Arctic" with recent alpine and/or arctic distribution patterns. These different molecular biogeographical patterns are presented using actual examples. Many "Mediterranean" species are differentiated into three major European genetic lineages, which are due to glacial isolation in the three major Mediterranean peninsulas. Postglacial expansion in this group of species is mostly influenced by the barriers of the Pyrenees and the Alps with four resulting main patterns of postglacial range expansions. However, some cases are known with less than one genetic lineage per Mediterranean peninsula on the one hand, and others with a considerable genetic substructure within each of the Mediterranean peninsulas, Asia Minor and the Maghreb. These structures within the Mediterranean sub-centres are often rather strong and in several cases even predate the Pleistocene. For the "Continental" species, it could be shown that the formerly supposed postglacial spread from eastern Palearctic expansion centres is mostly not applicable. Quite the contrary, most of these species apparently had extra-Mediterranean centres of survival in Europe with special importance of the perialpine regions, the Carpathian Basin and parts of the Balkan Peninsula. In the group of "Alpine" and/or "Arctic" species, several molecular biogeographical patterns have been found, which support and improve the postulates based on

  14. Biogeography of photosynthetic light-harvesting genes in marine phytoplankton.

    Directory of Open Access Journals (Sweden)

    Thomas S Bibby

    Full Text Available BACKGROUND: Photosynthetic light-harvesting proteins are the mechanism by which energy enters the marine ecosystem. The dominant prokaryotic photoautotrophs are the cyanobacterial genera Prochlorococcus and Synechococcus that are defined by two distinct light-harvesting systems, chlorophyll-bound protein complexes or phycobilin-bound protein complexes, respectively. Here, we use the Global Ocean Sampling (GOS Project as a unique and powerful tool to analyze the environmental diversity of photosynthetic light-harvesting genes in relation to available metadata including geographical location and physical and chemical environmental parameters. METHODS: All light-harvesting gene fragments and their metadata were obtained from the GOS database, aligned using ClustalX and classified phylogenetically. Each sequence has a name indicative of its geographic location; subsequent biogeographical analysis was performed by correlating light-harvesting gene budgets for each GOS station with surface chlorophyll concentration. CONCLUSION/SIGNIFICANCE: Using the GOS data, we have mapped the biogeography of light-harvesting genes in marine cyanobacteria on ocean-basin scales and show that an environmental gradient exists in which chlorophyll concentration is correlated to diversity of light-harvesting systems. Three functionally distinct types of light-harvesting genes are defined: (1 the phycobilisome (PBS genes of Synechococcus; (2 the pcb genes of Prochlorococcus; and (3 the iron-stress-induced (isiA genes present in some marine Synechococcus. At low chlorophyll concentrations, where nutrients are limited, the Pcb-type light-harvesting system shows greater genetic diversity; whereas at high chlorophyll concentrations, where nutrients are abundant, the PBS-type light-harvesting system shows higher genetic diversity. We interpret this as an environmental selection of specific photosynthetic strategy. Importantly, the unique light-harvesting system isiA is found

  15. Functional and phylogenetic structure of island bird communities.

    Science.gov (United States)

    Si, Xingfeng; Cadotte, Marc W; Zeng, Di; Baselga, Andrés; Zhao, Yuhao; Li, Jiaqi; Wu, Yiru; Wang, Siyu; Ding, Ping

    2017-05-01

    Biodiversity change in anthropogenically transformed habitats is often nonrandom, yet the nature and importance of the different mechanisms shaping community structure are unclear. Here, we extend the classic Theory of Island Biogeography (TIB) to account for nonrandom processes by incorporating species traits and phylogenetic relationships into a study of faunal relaxation following habitat loss and fragmentation. Two possible mechanisms can create nonrandom community patterns on fragment islands. First, small and isolated islands might consist of similar or closely related species because they are environmentally homogeneous or select for certain shared traits, such as dispersal ability. Alternatively, communities on small islands might contain more dissimilar or distantly related species than on large islands because limited space and resource availability result in greater competitive exclusion among species with high niche overlap. Breeding birds were surveyed on 36 islands and two mainland sites annually from 2010 to 2014 in the Thousand Island Lake region, China. We assessed community structure of breeding birds on these subtropical land-bridge islands by integrating species' trait and evolutionary distances. We additionally analysed habitat heterogeneity and variance in size ratios to distinguish biotic and abiotic processes of community assembly. Results showed that functional-phylogenetic diversity increased with island area, and decreased with isolation. Bird communities on the mainland were more diverse and generally less clustered than island bird communities and not different than randomly assembled communities. Bird communities on islands tend to be functionally similar and phylogenetically clustered, especially on small and isolated islands. The nonrandom decline in species diversity and change in bird community structure with island area and isolation, along with the relatively homogeneous habitats on small islands, support the environmental

  16. The critical catastrophe revisited

    International Nuclear Information System (INIS)

    De Mulatier, Clélia; Rosso, Alberto; Dumonteil, Eric; Zoia, Andrea

    2015-01-01

    The neutron population in a prototype model of nuclear reactor can be described in terms of a collection of particles confined in a box and undergoing three key random mechanisms: diffusion, reproduction due to fissions, and death due to absorption events. When the reactor is operated at the critical point, and fissions are exactly compensated by absorptions, the whole neutron population might in principle go to extinction because of the wild fluctuations induced by births and deaths. This phenomenon, which has been named critical catastrophe, is nonetheless never observed in practice: feedback mechanisms acting on the total population, such as human intervention, have a stabilizing effect. In this work, we revisit the critical catastrophe by investigating the spatial behaviour of the fluctuations in a confined geometry. When the system is free to evolve, the neutrons may display a wild patchiness (clustering). On the contrary, imposing a population control on the total population acts also against the local fluctuations, and may thus inhibit the spatial clustering. The effectiveness of population control in quenching spatial fluctuations will be shown to depend on the competition between the mixing time of the neutrons (i.e. the average time taken for a particle to explore the finite viable space) and the extinction time

  17. Magnetic moments revisited

    International Nuclear Information System (INIS)

    Towner, I.S.; Khanna, F.C.

    1984-01-01

    Consideration of core polarization, isobar currents and meson-exchange processes gives a satisfactory understanding of the ground-state magnetic moments in closed-shell-plus (or minus)-one nuclei, A = 3, 15, 17, 39 and 41. Ever since the earliest days of the nuclear shell model the understanding of magnetic moments of nuclear states of supposedly simple configurations, such as doubly closed LS shells +-1 nucleon, has been a challenge for theorists. The experimental moments, which in most cases are known with extraordinary precision, show a small yet significant departure from the single-particle Schmidt values. The departure, however, is difficult to evaluate precisely since, as will be seen, it results from a sensitive cancellation between several competing corrections each of which can be as large as the observed discrepancy. This, then, is the continuing fascination of magnetic moments. In this contribution, we revisit the subjet principally to identify the role played by isobar currents, which are of much concern at this conference. But in so doing we warn quite strongly of the dangers of considering just isobar currents in isolation; equal consideration must be given to competing processes which in this context are the mundane nuclear structure effects, such as core polarization, and the more popular meson-exchange currents

  18. Lorentz violation naturalness revisited

    Energy Technology Data Exchange (ETDEWEB)

    Belenchia, Alessio; Gambassi, Andrea; Liberati, Stefano [SISSA - International School for Advanced Studies, via Bonomea 265, 34136 Trieste (Italy); INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste (Italy)

    2016-06-08

    We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-energy percolation also in this case.

  19. SpeciesGeoCoder: Fast Categorization of Species Occurrences for Analyses of Biodiversity, Biogeography, Ecology, and Evolution.

    Science.gov (United States)

    Töpel, Mats; Zizka, Alexander; Calió, Maria Fernanda; Scharn, Ruud; Silvestro, Daniele; Antonelli, Alexandre

    2017-03-01

    Understanding the patterns and processes underlying the uneven distribution of biodiversity across space constitutes a major scientific challenge in systematic biology and biogeography, which largely relies on effectively mapping and making sense of rapidly increasing species occurrence data. There is thus an urgent need for making the process of coding species into spatial units faster, automated, transparent, and reproducible. Here we present SpeciesGeoCoder, an open-source software package written in Python and R, that allows for easy coding of species into user-defined operational units. These units may be of any size and be purely spatial (i.e., polygons) such as countries and states, conservation areas, biomes, islands, biodiversity hotspots, and areas of endemism, but may also include elevation ranges. This flexibility allows scoring species into complex categories, such as those encountered in topographically and ecologically heterogeneous landscapes. In addition, SpeciesGeoCoder can be used to facilitate sorting and cleaning of occurrence data obtained from online databases, and for testing the impact of incorrect identification of specimens on the spatial coding of species. The various outputs of SpeciesGeoCoder include quantitative biodiversity statistics, global and local distribution maps, and files that can be used directly in many phylogeny-based applications for ancestral range reconstruction, investigations of biome evolution, and other comparative methods. Our simulations indicate that even datasets containing hundreds of millions of records can be analyzed in relatively short time using a standard computer. We exemplify the use of SpeciesGeoCoder by inferring the historical dispersal of birds across the Isthmus of Panama, showing that lowland species crossed the Isthmus about twice as frequently as montane species with a marked increase in the number of dispersals during the last 10 million years. [ancestral area reconstruction; biodiversity

  20. Leadership and Management Theories Revisited

    DEFF Research Database (Denmark)

    Madsen, Mona Toft

    2001-01-01

    The goal of the paper is to revisit and analyze key contributions to the understanding of leadership and management. As a part of the discussion a role perspective that allows for additional and/or integrated leader dimensions, including a change-centered, will be outlined. Seemingly, a major...

  1. Revisiting Inter-Genre Similarity

    DEFF Research Database (Denmark)

    Sturm, Bob L.; Gouyon, Fabien

    2013-01-01

    We revisit the idea of ``inter-genre similarity'' (IGS) for machine learning in general, and music genre recognition in particular. We show analytically that the probability of error for IGS is higher than naive Bayes classification with zero-one loss (NB). We show empirically that IGS does...... not perform well, even for data that satisfies all its assumptions....

  2. POETIC AND PICTORIAL REVISITS OF THE MOZAMBIQUE ISLAND

    Directory of Open Access Journals (Sweden)

    Carmen Lucia Tindó Secco

    2012-11-01

    Full Text Available The rewriting of Mozambique with the pen of poetry and the ink of affections. Landscapes: poetry, painting and history. The intercrossing of people, cultures and different knowledges in the Mozambican ground of multiple inheritances.

  3. Class renormalization: islands around islands

    International Nuclear Information System (INIS)

    Meiss, J.D.

    1986-01-01

    An orbit of 'class' is one that rotates about a periodic orbit of one lower class with definite frequency. This contrasts to the 'level' of a periodic orbit which is the number of elements in its continued fraction expansion. Level renormalization is conventionally used to study the structure of quasi-periodic orbits. The scaling structure of periodic orbits encircling other periodic orbits in area preserving maps is discussed here. Fixed points corresponding to the accumulation of p/q bifurcations are found and scaling exponents determined. Fixed points for q > 2 correspond to self-similar islands around islands. Frequencies of the island boundary circles at the fixed points are obtained. Importance of this scaling for the motion of particles in stochastic regions is emphasized. (author)

  4. Tracing the temporal and spatial origins of island endemics in the Mediterranean region: a case study from the citrus family (Ruta L., Rutaceae).

    Science.gov (United States)

    Salvo, Gabriele; Ho, Simon Y W; Rosenbaum, Gideon; Ree, Richard; Conti, Elena

    2010-12-01

    Understanding the origin of island endemics is a central task of historical biogeography. Recent methodological advances provide a rigorous framework to determine the relative contribution of different biogeographic processes (e.g., vicariance, land migration, long-distance dispersal) to the origin of island endemics. With its complex but well-known history of microplate movements and climatic oscillations, the Mediterranean region (including the Mediterranean basin and Macaronesia) provides the geographic backdrop for the diversification of Ruta L., the type genus of Rutaceae (citrus family). Phylogenetic, molecular dating, and ancestral range reconstruction analyses were carried out to investigate the extent to which past geological connections and climatic history of the Mediterranean region explain the current distribution of species in Ruta, with emphasis on its island endemics. The analyses showed that Ruta invaded the region from the north well before the onset of the Mediterranean climate and diversified in situ as the climate became Mediterranean. The continental fragment island endemics of the genus originated via processes of land migration/vicariance driven by connections/disconnections between microplates, whereas the oceanic island endemics were the product of a single colonization event from the mainland followed by in situ diversification. This study emphasizes the need for an integrative, hypothesis-based approach to historical biogeography and stresses the importance of temporary land connections and colonization opportunity in the biotic assembly of continental fragment and oceanic islands, respectively.

  5. 'Counterfeit deviance' revisited.

    Science.gov (United States)

    Griffiths, Dorothy; Hingsburger, Dave; Hoath, Jordan; Ioannou, Stephanie

    2013-09-01

    The field has seen a renewed interest in exploring the theory of 'counterfeit deviance' for persons with intellectual disability who sexually offend. The term was first presented in 1991 by Hingsburger, Griffiths and Quinsey as a means to differentiate in clinical assessment a subgroup of persons with intellectual disability whose behaviours appeared like paraphilia but served a function that was not related to paraphilia sexual urges or fantasies. Case observations were put forward to provide differential diagnosis of paraphilia in persons with intellectual disabilities compared to those with counterfeit deviance. The brief paper was published in a journal that is no longer available and as such much of what is currently written on the topic is based on secondary sources. The current paper presents a theoretical piece to revisit the original counterfeit deviance theory to clarify the myths and misconceptions that have arisen and evaluate the theory based on additional research and clinical findings. The authors also propose areas where there may be a basis for expansion of the theory. The theory of counterfeit deviance still has relevance as a consideration for clinicians when assessing the nature of a sexual offence committed by a person with an intellectual disability. Clinical differentiation of paraphilia from counterfeit deviance provides a foundation for intervention that is designed to specifically treat the underlying factors that contributed to the offence for a given individual. Counterfeit deviance is a concept that continues to provide areas for consideration for clinicians regarding the assessment and treatment of an individual with an intellectual disability who has sexually offended. It is not and never was an explanation for all sexually offending behavior among persons with intellectual disabilities. © 2013 John Wiley & Sons Ltd.

  6. Gaussian entanglement revisited

    Science.gov (United States)

    Lami, Ludovico; Serafini, Alessio; Adesso, Gerardo

    2018-02-01

    We present a novel approach to the separability problem for Gaussian quantum states of bosonic continuous variable systems. We derive a simplified necessary and sufficient separability criterion for arbitrary Gaussian states of m versus n modes, which relies on convex optimisation over marginal covariance matrices on one subsystem only. We further revisit the currently known results stating the equivalence between separability and positive partial transposition (PPT) for specific classes of Gaussian states. Using techniques based on matrix analysis, such as Schur complements and matrix means, we then provide a unified treatment and compact proofs of all these results. In particular, we recover the PPT-separability equivalence for: (i) Gaussian states of 1 versus n modes; and (ii) isotropic Gaussian states. In passing, we also retrieve (iii) the recently established equivalence between separability of a Gaussian state and and its complete Gaussian extendability. Our techniques are then applied to progress beyond the state of the art. We prove that: (iv) Gaussian states that are invariant under partial transposition are necessarily separable; (v) the PPT criterion is necessary and sufficient for separability for Gaussian states of m versus n modes that are symmetric under the exchange of any two modes belonging to one of the parties; and (vi) Gaussian states which remain PPT under passive optical operations can not be entangled by them either. This is not a foregone conclusion per se (since Gaussian bound entangled states do exist) and settles a question that had been left unanswered in the existing literature on the subject. This paper, enjoyable by both the quantum optics and the matrix analysis communities, overall delivers technical and conceptual advances which are likely to be useful for further applications in continuous variable quantum information theory, beyond the separability problem.

  7. Izmit Foreshocks Revisited

    Science.gov (United States)

    Ellsworth, W. L.; Bulut, F.

    2016-12-01

    Much of what we know about the initiation of earthquakes comes from the temporal and spatial relationship of foreshocks to the initiation point of the mainshock. The 1999 Mw 7.6 Izmit, Turkey, earthquake was preceded by a 44 minute-long foreshock sequence. Bouchon et al. (Science, 2011) analyzed the foreshocks using a single seismic station, UCG, located to the north of the east-west fault, and concluded on the basis of waveform similarity that the foreshocks repeatedly re-ruptured the same fault patch, driven by slow slip at the base of the crust. We revisit the foreshock sequence using seismograms from 9 additional stations that recorded the four largest foreshocks (Mw 2.0 to 2.8) to better characterize spatial and temporal evolution of the foreshock sequence and their relationship to the mainshock hypocenter. Cross-correlation timing and hypocentroid location with hypoDD reveals a systematic west-to-east propagation of the four largest foreshocks toward the mainshock hypocenter. Foreshock rupture dimensions estimated using spectral ratios imply no major overlap for the first three foreshocks. The centroid of 4th and largest foreshock continues the eastward migration, but lies within the circular source area of the 3rd. The 3rd, however, has a low stress drop and strong directivity to the west . The mainshock hypocenter locates on the eastern edge of foreshock 4. We also re-analyzed waveform similarity of all 18 foreshocks recorded at UCG by removing the common mode signal and clustering the residual seismogram using the correlation coefficient as the distance metric. The smaller foreshocks cluster with the larger events in time order, sometimes as foreshocks and more commonly as aftershocks. These observations show that the Izmit foreshock sequence is consistent with a stress-transfer driven cascade, moving systematically to the east along the fault and that there is no observational requirement for creep as a driving mechanism.

  8. On the Convergence of Biogeography-Based Optimization for Binary Problems

    Directory of Open Access Journals (Sweden)

    Haiping Ma

    2014-01-01

    Full Text Available Biogeography-based optimization (BBO is an evolutionary algorithm inspired by biogeography, which is the study of the migration of species between habitats. A finite Markov chain model of BBO for binary problems was derived in earlier work, and some significant theoretical results were obtained. This paper analyzes the convergence properties of BBO on binary problems based on the previously derived BBO Markov chain model. Analysis reveals that BBO with only migration and mutation never converges to the global optimum. However, BBO with elitism, which maintains the best candidate in the population from one generation to the next, converges to the global optimum. In spite of previously published differences between genetic algorithms (GAs and BBO, this paper shows that the convergence properties of BBO are similar to those of the canonical GA. In addition, the convergence rate estimate of BBO with elitism is obtained in this paper and is confirmed by simulations for some simple representative problems.

  9. Molecular systematics and biogeography of the Hemigalinae civets (Mammalia, Carnivora

    Directory of Open Access Journals (Sweden)

    Géraldine Veron

    2017-02-01

    Full Text Available Due to the difficulty in obtaining samples, the systematics of the Hemigalinae civets has not been fully resolved. The aim of this study was to clarify the relationships of the species and the intraspecific diversity within this subfamily, and to explore the environmental factors that might have affected its evolution. Using two mitochondrial and two nuclear markers, we confirmed that the Hemigalinae comprises Owston’s civet, the otter civet, Hose’s civet and the banded civet, but also the Sulawesi palm civet (formerly included in the Paradoxurinae. Our study showed that the banded and Owston’s civets are sister species, and suggested that Hose’s civet is sister to these two. Within the banded civet, we observed a high divergence between individuals from the Mentawai Islands and those from Sumatra and Borneo (while the latter two were not strongly divergent, likely due to the deep sea channel between the Mentawai Islands and Sumatra. Unexpectedly, the Sumatran and Peninsular Malaysian individuals were not closely related, despite the fact that these two regions have repeatedly been connected during the last glaciations. No high polymorphism was found within Owston’s civet, although three groups were obtained: southern China, northern Vietnam and central Vietnam, which might be related to Pleistocene climatic fluctuations.

  10. Dynamic Topography Revisited

    Science.gov (United States)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The

  11. Radiation risks revisited

    International Nuclear Information System (INIS)

    Ackland, L.

    1993-01-01

    The Stewart team's findings are based on previously restricted Hanford data that the U.S. Dept. of Energy began releasing in 1990 to settle a lawsuit filed by the Three Mile Island Public Health Fund. The records include those of the 7,342 workers who died before 1987 and were employed at the plant between 1944 and 1978. These workers were among more than 35,000 men and women whose radiation doses were measured by film-badge monitoring during this period. According to contemporary radiation standards, these recorded exposures were safe. But Stewart and Kneale, using a new technique to more effectively isolate occupational doses from other causes of cancer, have calculated that approximately 3 percent of the 1,732 cancer deaths in the group resulted from work-place radiation exposure

  12. Remembered Experiences and Revisit Intentions

    DEFF Research Database (Denmark)

    Barnes, Stuart; Mattsson, Jan; Sørensen, Flemming

    2016-01-01

    Tourism is an experience-intensive sector in which customers seek and pay for experiences above everything else. Remembering past tourism experiences is also crucial for an understanding of the present, including the predicted behaviours of visitors to tourist destinations. We adopt a longitudinal...... approach to memory data collection from psychological science, which has the potential to contribute to our understanding of tourist behaviour. In this study, we examine the impact of remembered tourist experiences in a safari park. In particular, using matched survey data collected longitudinally and PLS...... path modelling, we examine the impact of positive affect tourist experiences on the development of revisit intentions. We find that longer-term remembered experiences have the strongest impact on revisit intentions, more so than predicted or immediate memory after an event. We also find that remembered...

  13. Revisiting Mutual Fund Performance Evaluation

    OpenAIRE

    Angelidis, Timotheos; Giamouridis, Daniel; Tessaromatis, Nikolaos

    2012-01-01

    Mutual fund manager excess performance should be measured relative to their self-reported benchmark rather than the return of a passive portfolio with the same risk characteristics. Ignoring the self-reported benchmark introduces biases in the measurement of stock selection and timing components of excess performance. We revisit baseline empirical evidence in mutual fund performance evaluation utilizing stock selection and timing measures that address these biases. We introduce a new factor e...

  14. Voltage Profile Enhancement and Reduction of Real Power loss by Hybrid Biogeography Based Artificial Bee Colony algorithm

    Directory of Open Access Journals (Sweden)

    K. Lenin

    2014-04-01

    Full Text Available This paper presents Hybrid Biogeography algorithm for solving the multi-objective reactive power dispatch problem in a power system. Real Power Loss minimization and maximization of voltage stability margin are taken as the objectives. Artificial bee colony optimization (ABC is quick and forceful algorithm for global optimization. Biogeography-Based Optimization (BBO is a new-fangled biogeography inspired algorithm. It mainly utilizes the biogeography-based relocation operator to share the information among solutions. In this work, a hybrid algorithm with BBO and ABC is projected, and named as HBBABC (Hybrid Biogeography based Artificial Bee Colony Optimization, for the universal numerical optimization problem. HBBABC merge the searching behavior of ABC with that of BBO. Both the algorithms have different solution probing tendency like ABC have good exploration probing tendency while BBO have good exploitation probing tendency.  HBBABC used to solve the reactive power dispatch problem and the proposed technique has been tested in standard IEEE30 bus test system.

  15. Continental Island Formation and the Archaeology of Defaunation on Zanzibar, Eastern Africa.

    Directory of Open Access Journals (Sweden)

    Mary E Prendergast

    Full Text Available With rising sea levels at the end of the Pleistocene, land-bridge or continental islands were formed around the world. Many of these islands have been extensively studied from a biogeographical perspective, particularly in terms of impacts of island creation on terrestrial vertebrates. However, a majority of studies rely on contemporary faunal distributions rather than fossil data. Here, we present archaeological findings from the island of Zanzibar (also known as Unguja off the eastern African coast, to provide a temporal perspective on island biogeography. The site of Kuumbi Cave, excavated by multiple teams since 2005, has revealed the longest cultural and faunal record for any eastern African island. This record extends to the Late Pleistocene, when Zanzibar was part of the mainland, and attests to the extirpation of large mainland mammals in the millennia after the island became separated. We draw on modeling and sedimentary data to examine the process by which Zanzibar was most recently separated from the mainland, providing the first systematic insights into the nature and chronology of this process. We subsequently investigate the cultural and faunal record from Kuumbi Cave, which provides at least five key temporal windows into human activities and faunal presence: two at the end of the Last Glacial Maximum (LGM, one during the period of post-LGM rapid sea level rise and island formation, and two in the late Holocene (Middle Iron Age and Late Iron Age. This record demonstrates the presence of large mammals during the period of island formation, and their severe reduction or disappearance in the Kuumbi Cave sequence by the late Holocene. While various limitations, including discontinuity in the sequence, problematize attempts to clearly attribute defaunation to anthropogenic or island biogeographic processes, Kuumbi Cave offers an unprecedented opportunity to examine post-Pleistocene island formation and its long-term consequences for

  16. Continental Island Formation and the Archaeology of Defaunation on Zanzibar, Eastern Africa

    Science.gov (United States)

    Prendergast, Mary E.; Rouby, Hélène; Punnwong, Paramita; Marchant, Robert; Crowther, Alison; Kourampas, Nikos; Shipton, Ceri; Walsh, Martin; Lambeck, Kurt; Boivin, Nicole L.

    2016-01-01

    With rising sea levels at the end of the Pleistocene, land-bridge or continental islands were formed around the world. Many of these islands have been extensively studied from a biogeographical perspective, particularly in terms of impacts of island creation on terrestrial vertebrates. However, a majority of studies rely on contemporary faunal distributions rather than fossil data. Here, we present archaeological findings from the island of Zanzibar (also known as Unguja) off the eastern African coast, to provide a temporal perspective on island biogeography. The site of Kuumbi Cave, excavated by multiple teams since 2005, has revealed the longest cultural and faunal record for any eastern African island. This record extends to the Late Pleistocene, when Zanzibar was part of the mainland, and attests to the extirpation of large mainland mammals in the millennia after the island became separated. We draw on modeling and sedimentary data to examine the process by which Zanzibar was most recently separated from the mainland, providing the first systematic insights into the nature and chronology of this process. We subsequently investigate the cultural and faunal record from Kuumbi Cave, which provides at least five key temporal windows into human activities and faunal presence: two at the end of the Last Glacial Maximum (LGM), one during the period of post-LGM rapid sea level rise and island formation, and two in the late Holocene (Middle Iron Age and Late Iron Age). This record demonstrates the presence of large mammals during the period of island formation, and their severe reduction or disappearance in the Kuumbi Cave sequence by the late Holocene. While various limitations, including discontinuity in the sequence, problematize attempts to clearly attribute defaunation to anthropogenic or island biogeographic processes, Kuumbi Cave offers an unprecedented opportunity to examine post-Pleistocene island formation and its long-term consequences for human and animal

  17. Continental Island Formation and the Archaeology of Defaunation on Zanzibar, Eastern Africa.

    Science.gov (United States)

    Prendergast, Mary E; Rouby, Hélène; Punnwong, Paramita; Marchant, Robert; Crowther, Alison; Kourampas, Nikos; Shipton, Ceri; Walsh, Martin; Lambeck, Kurt; Boivin, Nicole L

    2016-01-01

    With rising sea levels at the end of the Pleistocene, land-bridge or continental islands were formed around the world. Many of these islands have been extensively studied from a biogeographical perspective, particularly in terms of impacts of island creation on terrestrial vertebrates. However, a majority of studies rely on contemporary faunal distributions rather than fossil data. Here, we present archaeological findings from the island of Zanzibar (also known as Unguja) off the eastern African coast, to provide a temporal perspective on island biogeography. The site of Kuumbi Cave, excavated by multiple teams since 2005, has revealed the longest cultural and faunal record for any eastern African island. This record extends to the Late Pleistocene, when Zanzibar was part of the mainland, and attests to the extirpation of large mainland mammals in the millennia after the island became separated. We draw on modeling and sedimentary data to examine the process by which Zanzibar was most recently separated from the mainland, providing the first systematic insights into the nature and chronology of this process. We subsequently investigate the cultural and faunal record from Kuumbi Cave, which provides at least five key temporal windows into human activities and faunal presence: two at the end of the Last Glacial Maximum (LGM), one during the period of post-LGM rapid sea level rise and island formation, and two in the late Holocene (Middle Iron Age and Late Iron Age). This record demonstrates the presence of large mammals during the period of island formation, and their severe reduction or disappearance in the Kuumbi Cave sequence by the late Holocene. While various limitations, including discontinuity in the sequence, problematize attempts to clearly attribute defaunation to anthropogenic or island biogeographic processes, Kuumbi Cave offers an unprecedented opportunity to examine post-Pleistocene island formation and its long-term consequences for human and animal

  18. Biodiversity, biogeography and phylogeography of Ordovician rhynchonelliform brachiopods

    DEFF Research Database (Denmark)

    Harper, David A. T.; Mac Ørum Rasmussen, Christian; Liljeroth, Maria

    2013-01-01

    -levels were high. Pivotal to the entire diversification is the role of gamma (inter-provincial) diversity and by implication the spread of the continents and frequency of island arcs and microcontinents. The phylogeographical analysis demonstrates that this new palaeogeographical configuration...... with local biodiversity epicentres, notably on the South China Palaeoplate; low-latitude porambonitoid-dominated faunas with early plectambonitoid and clitambonitoid representatives, as well as high-latitude assemblages mostly dominated by orthoids, can be recognized, but many taxa are rooted in Late......The phylogeographical evolution and the consequent changing distribution and diversity of rhynchonelliform brachiopods through the Ordovician are linked to the dynamic palaeogeography of the period. The Early Ordovician (Tremadocian and Floian) is characterized by globally low-diversity faunas...

  19. A new biogeographically disjunct giant gecko (Gehyra: Gekkonidae: Reptilia) from the East Melanesian Islands

    Science.gov (United States)

    Oliver, Paul M.; Clegg, Jonathan R.; Fisher, Robert N.; Richards, Stephen J.; Taylor, Peter N.; Jocque, Merlijn M. T.

    2016-01-01

    The East Melanesian Islands have been a focal area for research into island biogeography and community ecology. However, previously undescribed and biogeographically significant new species endemic to this region continue to be discovered. Here we describe a phylogenetically distinct (~20% divergence at the mitochondrial ND2 gene) and biogeographically disjunct new species of gecko in the genus Gehyra, from the Admiralty and St Matthias Islands. Gehyra rohan sp. nov. can be distinguished from all congeners by the combination of its very large size, ring of bright orange scales around the eye, moderate degree of lateral folding on the limbs and body, and aspects of head, body and tail scalation. Molecular data indicate mid to late Miocene divergence of the new species from nearest relatives occurring nearly 2000 kilometres away in Vanuatu and Fiji. Large Gehyra have not been recorded on the intervening large islands of the Bismark Archipelago (New Britain and New Ireland) and the Solomon Islands, suggesting this dispersal pre-dated the current configuration of these islands, extinction in intervening regions, or potentially elements of both. Conversely, low genetic divergence between disjunct samples on Manus and Mussau implies recent overseas dispersal via either natural or anthropogenic means.

  20. Tenarife Island, Canary Island Archipelago, Atlantic Ocean

    Science.gov (United States)

    1991-01-01

    Tenarife Island is one of the most volcanically active of the Canary Island archipelago, Atlantic Ocean, just off the NW coast of Africa, (28.5N, 16.5W). The old central caldera, nearly filled in by successive volcanic activity culminating in two stratocones. From those two peaks, a line of smaller cinder cones extend to the point of the island. Extensive gullies dissect the west side of the island and some forests still remain on the east side.

  1. Generic phylogeny, historical biogeography and character evolution of the cosmopolitan aquatic plant family Hydrocharitaceae.

    Science.gov (United States)

    Chen, Ling-Yun; Chen, Jin-Ming; Gituru, Robert Wahiti; Wang, Qing-Feng

    2012-03-10

    Hydrocharitaceae is a fully aquatic monocot family, consists of 18 genera with approximately 120 species. The family includes both fresh and marine aquatics and exhibits great diversity in form and habit including annual and perennial life histories; submersed, partially submersed and floating leaf habits and linear to orbicular leaf shapes. The family has a cosmopolitan distribution and is well represented in the Tertiary fossil record in Europe. At present, the historical biogeography of the family is not well understood and the generic relationships remain controversial. In this study we investigated the phylogeny and biogeography of Hydrocharitaceae by integrating fossils and DNA sequences from eight genes. We also conducted ancestral state reconstruction for three morphological characters. Phylogenetic analyses produced a phylogeny with most branches strongly supported by bootstrap values greater than 95 and Bayesian posterior probability values of 1.0. Stratiotes is the first diverging lineage with the remaining genera in two clades, one clade consists of Lagarosiphon, Ottelia, Blyxa, Apalanthe, Elodea and Egeria; and the other consists of Hydrocharis-Limnobium, Thalassia, Enhalus, Halophila, Najas, Hydrilla, Vallisneria, Nechamandra and Maidenia. Biogeographic analyses (DIVA, Mesquite) and divergence time estimates (BEAST) resolved the most recent common ancestor of Hydrocharitaceae as being in Asia during the Late Cretaceous and Palaeocene (54.7-72.6 Ma). Dispersals (including long-distance dispersal and migrations through Tethys seaway and land bridges) probably played major roles in the intercontinental distribution of this family. Ancestral state reconstruction suggested that in Hydrocharitaceae evolution of dioecy is bidirectional, viz., from dioecy to hermaphroditism, and from hermaphroditism to dioecy, and that the aerial-submerged leaf habit and short-linear leaf shape are the ancestral states. Our study has shed light on the previously controversial

  2. Brains, tools, innovation and biogeography in crows and ravens

    Science.gov (United States)

    2012-01-01

    Background Crows and ravens (Passeriformes: Corvus) are large-brained birds with enhanced cognitive abilities relative to other birds. They are among the few non-hominid organisms on Earth to be considered intelligent and well-known examples exist of several crow species having evolved innovative strategies and even use of tools in their search for food. The 40 Corvus species have also been successful dispersers and are distributed on most continents and in remote archipelagos. Results This study presents the first molecular phylogeny including all species and a number of subspecies within the genus Corvus. We date the phylogeny and determine ancestral areas to investigate historical biogeographical patterns of the crows. Additionally, we use data on brain size and a large database on innovative behaviour and tool use to test whether brain size (i) explains innovative behaviour and success in applying tools when foraging and (ii) has some correlative role in the success of colonization of islands. Our results demonstrate that crows originated in the Palaearctic in the Miocene from where they dispersed to North America and the Caribbean, Africa and Australasia. We find that relative brain size alone does not explain tool use, innovative feeding strategies and dispersal success within crows. Conclusions Our study supports monophyly of the genus Corvus and further demonstrates the direction and timing of colonization from the area of origin in the Palaearctic to other continents and archipelagos. The Caribbean was probably colonized from North America, although some North American ancestor may have gone extinct, and the Pacific was colonized multiple times from Asia and Australia. We did not find a correlation between relative brain size, tool use, innovative feeding strategies and dispersal success. Hence, we propose that all crows and ravens have relatively large brains compared to other birds and thus the potential to be innovative if conditions and circumstances

  3. Schroedinger's variational method of quantization revisited

    International Nuclear Information System (INIS)

    Yasue, K.

    1980-01-01

    Schroedinger's original quantization procedure is revisited in the light of Nelson's stochastic framework of quantum mechanics. It is clarified why Schroedinger's proposal of a variational problem led us to a true description of quantum mechanics. (orig.)

  4. Tourists' perceptions and intention to revisit Norway

    OpenAIRE

    Lazar, Ana Florina; Komolikova-Blindheim, Galyna

    2016-01-01

    Purpose - The overall purpose of this study is to explore tourists' perceptions and their intention to revisit Norway. The aim is to find out what are the factors that drive the overall satisfaction, the willingness to recommend and the revisit intention of international tourists that spend their holiday in Norway. Design-Method-Approach - the Theory of Planned Behavior (Ajzen 1991), is used as a framework to investigate tourists' intention and behavior towards Norway as destination. The o...

  5. Genetic subdivision and biogeography of the Danubian rheophilic barb Barbus peteney inferred from phylogenetic analysis of mitochondrial DNA variation

    Czech Academy of Sciences Publication Activity Database

    Kotlík, Petr; Berrebi, P.

    2002-01-01

    Roč. 24, - (2002), s. 10-18 ISSN 1055-7903 R&D Projects: GA AV ČR IBS5045111; GA AV ČR KSK6005114 Keywords : biogeography * phylogeogrpahy * mtDNA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.590, year: 2002

  6. Historical biogeography and diversification of truffles in the Tuberaceae and their newly identified Southern hemisphere sister lineage

    Science.gov (United States)

    Gregory Bonito; Matthew E. Smith; Michael Nowak; Rosanne A. Healy; Gonzalo Guevara; Efren Cazares; Akihiko Kinoshita; Eduardo R. Nouhra; Laura S. Dominguez; Leho Tedersoo; Claude Murat; Yun Wang; Baldomero Arroyo Moreno; Donald H. Pfister; Kazuhide Nara; Alessandra Zambonelli; James M. Trappe; Rytas. Vilgalys

    2013-01-01

    In this study we reassessed the biogeography and origin of the Tuberaceae and their relatives using multiple loci and a global sampling of taxa. Multiple independent transitions from an aboveground to a belowground truffie fruiting body form have occurred in the Tuberaceae and in its newly recognized sister lineage...

  7. Revealing the secrets of African annonaceae : systematics, evolution and biogeography of the syncarpous genera Isolona and Monodora

    NARCIS (Netherlands)

    Couvreur, T.L.P.

    2008-01-01

    The goal of this PhD project was to study the evolution, systematics and biogeography of two African genera from the pan-tropical Annonaceae family: Isolona and Monodora. Both genera are unique within the family in that the female reproductive parts (or carpels) are fused into a single unit. All

  8. A Biogeography-Based Optimization Algorithm Hybridized with Tabu Search for the Quadratic Assignment Problem.

    Science.gov (United States)

    Lim, Wee Loon; Wibowo, Antoni; Desa, Mohammad Ishak; Haron, Habibollah

    2016-01-01

    The quadratic assignment problem (QAP) is an NP-hard combinatorial optimization problem with a wide variety of applications. Biogeography-based optimization (BBO), a relatively new optimization technique based on the biogeography concept, uses the idea of migration strategy of species to derive algorithm for solving optimization problems. It has been shown that BBO provides performance on a par with other optimization methods. A classical BBO algorithm employs the mutation operator as its diversification strategy. However, this process will often ruin the quality of solutions in QAP. In this paper, we propose a hybrid technique to overcome the weakness of classical BBO algorithm to solve QAP, by replacing the mutation operator with a tabu search procedure. Our experiments using the benchmark instances from QAPLIB show that the proposed hybrid method is able to find good solutions for them within reasonable computational times. Out of 61 benchmark instances tested, the proposed method is able to obtain the best known solutions for 57 of them.

  9. Biogeography of speciation in Cenozoic marine ostracoda: the role of climatic change

    Energy Technology Data Exchange (ETDEWEB)

    Cronin, T.M.

    1985-01-01

    Evolutionary theory holds that geographic isolation of populations with its resultant reproductive isolation is an important factor in the origin of new species. Climatic change alters species' biogeography by creating and eliminating barriers that affect gene flow between populations. For benthic organisms such as shallow marine ostracodes, thermal gradients at biogeographic province boundaries and the area of continental shelf are factors affected by climatic and associated sea level changes. Studies of Cenozoic marine ostracodes show that allopatric speciation does not account for paleobiogeographic patterns of species subjected to climatic change. Studies of 127 endemic species from middle latitudes of the western Atlantic show that most speciation events in temperature and subtropical taxa are, in the zoogeographic sense, sympatric or parapatric-clinal and are induced by oceanographic changes related to climatic events rather than geographic isolation of populations. Most ostracode species in middle latitudes are adapted to frequent, cyclical climatic changes typical of these regions and originated during rare periods of major climatic transition. High-latitude arctic-subarctic genera such as Finmarchinella have circumpolar distributions. A parapatric-clinal model accounts for speciation patterns observed in some high-latitude and tropical taxa. However the dynamic nature of thermal gradients and species' biogeography during climatic change renders questionable the controversial distinction between parapatric and allopatric-peripatric speciation models.

  10. Biogeography of worm lizards (Amphisbaenia) driven by end-Cretaceous mass extinction.

    Science.gov (United States)

    Longrich, Nicholas R; Vinther, Jakob; Pyron, R Alexander; Pisani, Davide; Gauthier, Jacques A

    2015-05-07

    Worm lizards (Amphisbaenia) are burrowing squamates that live as subterranean predators. Their underground existence should limit dispersal, yet they are widespread throughout the Americas, Europe and Africa. This pattern was traditionally explained by continental drift, but molecular clocks suggest a Cenozoic diversification, long after the break-up of Pangaea, implying dispersal. Here, we describe primitive amphisbaenians from the North American Palaeocene, including the oldest known amphisbaenian, and provide new and older molecular divergence estimates for the clade, showing that worm lizards originated in North America, then radiated and dispersed in the Palaeogene following the Cretaceous-Palaeogene (K-Pg) extinction. This scenario implies at least three trans-oceanic dispersals: from North America to Europe, from North America to Africa and from Africa to South America. Amphisbaenians provide a striking case study in biogeography, suggesting that the role of continental drift in biogeography may be overstated. Instead, these patterns support Darwin and Wallace's hypothesis that the geographical ranges of modern clades result from dispersal, including oceanic rafting. Mass extinctions may facilitate dispersal events by eliminating competitors and predators that would otherwise hinder establishment of dispersing populations, removing biotic barriers to dispersal. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  11. Biogeography-based particle swarm optimization with fuzzy elitism and its applications to constrained engineering problems

    Science.gov (United States)

    Guo, Weian; Li, Wuzhao; Zhang, Qun; Wang, Lei; Wu, Qidi; Ren, Hongliang

    2014-11-01

    In evolutionary algorithms, elites are crucial to maintain good features in solutions. However, too many elites can make the evolutionary process stagnate and cannot enhance the performance. This article employs particle swarm optimization (PSO) and biogeography-based optimization (BBO) to propose a hybrid algorithm termed biogeography-based particle swarm optimization (BPSO) which could make a large number of elites effective in searching optima. In this algorithm, the whole population is split into several subgroups; BBO is employed to search within each subgroup and PSO for the global search. Since not all the population is used in PSO, this structure overcomes the premature convergence in the original PSO. Time complexity analysis shows that the novel algorithm does not increase the time consumption. Fourteen numerical benchmarks and four engineering problems with constraints are used to test the BPSO. To better deal with constraints, a fuzzy strategy for the number of elites is investigated. The simulation results validate the feasibility and effectiveness of the proposed algorithm.

  12. A Biogeography-Based Optimization Algorithm Hybridized with Tabu Search for the Quadratic Assignment Problem

    Science.gov (United States)

    Lim, Wee Loon; Wibowo, Antoni; Desa, Mohammad Ishak; Haron, Habibollah

    2016-01-01

    The quadratic assignment problem (QAP) is an NP-hard combinatorial optimization problem with a wide variety of applications. Biogeography-based optimization (BBO), a relatively new optimization technique based on the biogeography concept, uses the idea of migration strategy of species to derive algorithm for solving optimization problems. It has been shown that BBO provides performance on a par with other optimization methods. A classical BBO algorithm employs the mutation operator as its diversification strategy. However, this process will often ruin the quality of solutions in QAP. In this paper, we propose a hybrid technique to overcome the weakness of classical BBO algorithm to solve QAP, by replacing the mutation operator with a tabu search procedure. Our experiments using the benchmark instances from QAPLIB show that the proposed hybrid method is able to find good solutions for them within reasonable computational times. Out of 61 benchmark instances tested, the proposed method is able to obtain the best known solutions for 57 of them. PMID:26819585

  13. Oceanic protists with different forms of acquired phototrophy display contrasting biogeographies and abundance.

    Science.gov (United States)

    Leles, S G; Mitra, A; Flynn, K J; Stoecker, D K; Hansen, P J; Calbet, A; McManus, G B; Sanders, R W; Caron, D A; Not, F; Hallegraeff, G M; Pitta, P; Raven, J A; Johnson, M D; Glibert, P M; Våge, S

    2017-08-16

    This first comprehensive analysis of the global biogeography of marine protistan plankton with acquired phototrophy shows these mixotrophic organisms to be ubiquitous and abundant; however, their biogeography differs markedly between different functional groups. These mixotrophs, lacking a constitutive capacity for photosynthesis (i.e. non-constitutive mixotrophs, NCMs), acquire their phototrophic potential through either integration of prey-plastids or through endosymbiotic associations with photosynthetic microbes. Analysis of field data reveals that 40-60% of plankton traditionally labelled as (non-phototrophic) microzooplankton are actually NCMs, employing acquired phototrophy in addition to phagotrophy. Specialist NCMs acquire chloroplasts or endosymbionts from specific prey, while generalist NCMs obtain chloroplasts from a variety of prey. These contrasting functional types of NCMs exhibit distinct seasonal and spatial global distribution patterns. Mixotrophs reliant on 'stolen' chloroplasts, controlled by prey diversity and abundance, dominate in high-biomass areas. Mixotrophs harbouring intact symbionts are present in all waters and dominate particularly in oligotrophic open ocean systems. The contrasting temporal and spatial patterns of distribution of different mixotroph functional types across the oceanic provinces, as revealed in this study, challenges traditional interpretations of marine food web structures. Mixotrophs with acquired phototrophy (NCMs) warrant greater recognition in marine research. © 2017 The Author(s).

  14. Patterns of Arbuscular Mycorrhizal Fungal Distribution on Mainland and Island Sandy Coastal Plain Ecosystems in Brazil.

    Science.gov (United States)

    da Silva, Iolanda Ramalho; de Souza, Francisco Adriano; da Silva, Danielle Karla Alves; Oehl, Fritz; Maia, Leonor Costa

    2017-10-01

    Although sandy coastal plains are important buffer zones to protect the coast line and maintain biological diversity and ecosystem services, these ecosystems have been endangered by anthropogenic activities. Thus, information on coastal biodiversity and forces shaping coastal biological diversity are extremely important for effective conservation strategies. In this study, we aimed to compare arbuscular mycorrhizal (AM) fungal communities from soil samples collected on the mainland and nearby islands located in Brazilian sandy coastal plain ecosystems (Restingas) to get information about AM fungal biogeography and identify factors shaping these communities. Soil samples were collected in 2013 and 2014 on the beachfront of the tropical sandy coastal plain at six sites (three island and three mainland locations) across the northeast, southeast, and south regions of Brazil. Overall, we recorded 53 AM fungal species from field and trap culture samples. The richness and diversity of AM fungal species did not differ between mainland and island locations, but AM fungal community assemblages were different between mainland and island environments and among most sites sampled. Glomeromycota communities registered from island samples showed higher heterogeneity than communities from mainland samples. Sandy coastal plains harbor diverse AM fungal communities structured by climatic, edaphic, and spatial factors, while the distance from the colonizing source (mainland environments) does not strongly affect the AM fungal communities in Brazilian coastal environments.

  15. A review of the influence of biogeography, riverine linkages, and marine connectivity on fish assemblages in evolving lagoons and lakes of coastal southern Africa

    CSIR Research Space (South Africa)

    Whitfield, AK

    2017-09-01

    Full Text Available lakes), elements of the marine fish assemblage have persisted, especially the presence of facultative catadromous species. Freshwater fish diversity in coastal lakes and lagoons is a function of historical and present biogeography and salinity. From a...

  16. Researching Pacific island livelihoods:

    DEFF Research Database (Denmark)

    Egelund Christensen, Andreas; Mertz, Ole

    2010-01-01

    on contemporary theories of nissology and conceptual analytical frameworks for island research. Through a review of selected case-study-based island literature on changing livelihoods coming out of the South Pacific, we wish to illustrate and discuss advantages of finding common grounds for small island studies....... The focus is on two dimensions of island livelihood, migration and natural resource management, both of which are significant contributors in making island livelihoods and shaping Pacific seascapes. We argue that there is still a substantial lack of studies targeting small island dynamics that are empirical...

  17. The Levy sections theorem revisited

    International Nuclear Information System (INIS)

    Figueiredo, Annibal; Gleria, Iram; Matsushita, Raul; Silva, Sergio Da

    2007-01-01

    This paper revisits the Levy sections theorem. We extend the scope of the theorem to time series and apply it to historical daily returns of selected dollar exchange rates. The elevated kurtosis usually observed in such series is then explained by their volatility patterns. And the duration of exchange rate pegs explains the extra elevated kurtosis in the exchange rates of emerging markets. In the end, our extension of the theorem provides an approach that is simpler than the more common explicit modelling of fat tails and dependence. Our main purpose is to build up a technique based on the sections that allows one to artificially remove the fat tails and dependence present in a data set. By analysing data through the lenses of the Levy sections theorem one can find common patterns in otherwise very different data sets

  18. The power reinforcement framework revisited

    DEFF Research Database (Denmark)

    Nielsen, Jeppe; Andersen, Kim Normann; Danziger, James N.

    2016-01-01

    Whereas digital technologies are often depicted as being capable of disrupting long-standing power structures and facilitating new governance mechanisms, the power reinforcement framework suggests that information and communications technologies tend to strengthen existing power arrangements within...... public organizations. This article revisits the 30-yearold power reinforcement framework by means of an empirical analysis on the use of mobile technology in a large-scale programme in Danish public sector home care. It explores whether and to what extent administrative management has controlled decision......-making and gained most benefits from mobile technology use, relative to the effects of the technology on the street-level workers who deliver services. Current mobile technology-in-use might be less likely to be power reinforcing because it is far more decentralized and individualized than the mainly expert...

  19. The Levy sections theorem revisited

    Science.gov (United States)

    Figueiredo, Annibal; Gleria, Iram; Matsushita, Raul; Da Silva, Sergio

    2007-06-01

    This paper revisits the Levy sections theorem. We extend the scope of the theorem to time series and apply it to historical daily returns of selected dollar exchange rates. The elevated kurtosis usually observed in such series is then explained by their volatility patterns. And the duration of exchange rate pegs explains the extra elevated kurtosis in the exchange rates of emerging markets. In the end, our extension of the theorem provides an approach that is simpler than the more common explicit modelling of fat tails and dependence. Our main purpose is to build up a technique based on the sections that allows one to artificially remove the fat tails and dependence present in a data set. By analysing data through the lenses of the Levy sections theorem one can find common patterns in otherwise very different data sets.

  20. Generic phylogeny, historical biogeography and character evolution of the cosmopolitan aquatic plant family Hydrocharitaceae

    Directory of Open Access Journals (Sweden)

    Chen Ling-Yun

    2012-03-01

    Full Text Available Abstract Background Hydrocharitaceae is a fully aquatic monocot family, consists of 18 genera with approximately 120 species. The family includes both fresh and marine aquatics and exhibits great diversity in form and habit including annual and perennial life histories; submersed, partially submersed and floating leaf habits and linear to orbicular leaf shapes. The family has a cosmopolitan distribution and is well represented in the Tertiary fossil record in Europe. At present, the historical biogeography of the family is not well understood and the generic relationships remain controversial. In this study we investigated the phylogeny and biogeography of Hydrocharitaceae by integrating fossils and DNA sequences from eight genes. We also conducted ancestral state reconstruction for three morphological characters. Results Phylogenetic analyses produced a phylogeny with most branches strongly supported by bootstrap values greater than 95 and Bayesian posterior probability values of 1.0. Stratiotes is the first diverging lineage with the remaining genera in two clades, one clade consists of Lagarosiphon, Ottelia, Blyxa, Apalanthe, Elodea and Egeria; and the other consists of Hydrocharis-Limnobium, Thalassia, Enhalus, Halophila, Najas, Hydrilla, Vallisneria, Nechamandra and Maidenia. Biogeographic analyses (DIVA, Mesquite and divergence time estimates (BEAST resolved the most recent common ancestor of Hydrocharitaceae as being in Asia during the Late Cretaceous and Palaeocene (54.7-72.6 Ma. Dispersals (including long-distance dispersal and migrations through Tethys seaway and land bridges probably played major roles in the intercontinental distribution of this family. Ancestral state reconstruction suggested that in Hydrocharitaceae evolution of dioecy is bidirectional, viz., from dioecy to hermaphroditism, and from hermaphroditism to dioecy, and that the aerial-submerged leaf habit and short-linear leaf shape are the ancestral states. Conclusions

  1. Radiating on oceanic islands: patterns and processes of speciation in the land snail genus Theba (Risso 1826.

    Directory of Open Access Journals (Sweden)

    Carola Greve

    Full Text Available Island radiations have played a major role in shaping our current understanding of allopatric, sympatric and parapatric speciation. However, the fact that species divergence correlates with island size emphasizes the importance of geographic isolation (allopatry in speciation. Based on molecular and morphological data, we investigated the diversification of the land snail genus Theba on the two Canary Islands of Lanzarote and Fuerteventura. Due to the geological history of both islands, this study system provides ideal conditions to investigate the interplay of biogeography, dispersal ability and differentiation in generating species diversity. Our analyses demonstrated extensive cryptic diversification of Theba on these islands, probably driven mainly by non-adaptive allopatric differentiation and secondary gene flow. In a few cases, we observed a complete absence of gene flow among sympatrically distributed forms suggesting an advanced stage of speciation. On the Jandía peninsula genome scans suggested genotype-environment associations and potentially adaptive diversification of two closely related Theba species to different ecological environments. We found support for the idea that genetic differentiation was enhanced by divergent selection in different environments. The diversification of Theba on both islands is therefore best explained by a mixture of non-adaptive and adaptive speciation, promoted by ecological and geomorphological factors.

  2. Radiating on oceanic islands: patterns and processes of speciation in the land snail genus Theba (Risso 1826).

    Science.gov (United States)

    Greve, Carola; Gimnich, France; Hutterer, Rainer; Misof, Bernhard; Haase, Martin

    2012-01-01

    Island radiations have played a major role in shaping our current understanding of allopatric, sympatric and parapatric speciation. However, the fact that species divergence correlates with island size emphasizes the importance of geographic isolation (allopatry) in speciation. Based on molecular and morphological data, we investigated the diversification of the land snail genus Theba on the two Canary Islands of Lanzarote and Fuerteventura. Due to the geological history of both islands, this study system provides ideal conditions to investigate the interplay of biogeography, dispersal ability and differentiation in generating species diversity. Our analyses demonstrated extensive cryptic diversification of Theba on these islands, probably driven mainly by non-adaptive allopatric differentiation and secondary gene flow. In a few cases, we observed a complete absence of gene flow among sympatrically distributed forms suggesting an advanced stage of speciation. On the Jandía peninsula genome scans suggested genotype-environment associations and potentially adaptive diversification of two closely related Theba species to different ecological environments. We found support for the idea that genetic differentiation was enhanced by divergent selection in different environments. The diversification of Theba on both islands is therefore best explained by a mixture of non-adaptive and adaptive speciation, promoted by ecological and geomorphological factors.

  3. Trait-Dependent Biogeography: (Re)Integrating Biology into Probabilistic Historical Biogeographical Models.

    Science.gov (United States)

    Sukumaran, Jeet; Knowles, L Lacey

    2018-04-20

    The development of process-based probabilistic models for historical biogeography has transformed the field by grounding it in modern statistical hypothesis testing. However, most of these models abstract away biological differences, reducing species to interchangeable lineages. We present here the case for reintegration of biology into probabilistic historical biogeographical models, allowing a broader range of questions about biogeographical processes beyond ancestral range estimation or simple correlation between a trait and a distribution pattern, as well as allowing us to assess how inferences about ancestral ranges themselves might be impacted by differential biological traits. We show how new approaches to inference might cope with the computational challenges resulting from the increased complexity of these trait-based historical biogeographical models. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Where did the chili get its spice? Biogeography of capsaicinoid production in ancestral wild chili species.

    Science.gov (United States)

    Tewksbury, Joshua J; Manchego, Carlos; Haak, David C; Levey, Douglas J

    2006-03-01

    The biogeography of pungency in three species of wild chili in the chaco and surrounding highland habitats of southeastern Bolivia is described. We report that Capsicum chacoense, C. baccatum, and C. eximium are polymorphic for production of capsaicin and its analogs, such that completely pungent and completely nonpungent individuals co-occur in some populations. In C. chacoense, the density of plants and the proportion of pungent plants increased with elevation. Above 900 m, all individuals in all populations except two were pungent; nonpungent individuals in at least one of the two polymorphic populations were likely a result of spreading by humans. The occurrence of pungent and nonpungent individuals in three species of ancestral Capsicum and the geographic variation of pungency within species suggest that production of capsaicin and its analogs entails both costs and benefits, which shift from one locality to another. Determining the selection pressures behind such shifts is necessary to understand the evolution of pungency in chilies.

  5. Biodiversity and Biogeography of Chthamalid Barnacles from the North-Eastern Pacific (Crustacea Cirripedia.

    Directory of Open Access Journals (Sweden)

    Benny K K Chan

    Full Text Available The biogeography and ecology of the species of Chthamalus present on the west coast of America are described, using data from 51 localities from Alaska to Panama, together with their zonation on the shore with respect to that of other barnacles. The species present were C. dalli, Pilsbry 1916, C. fissus, Darwin, 1854, C. anisopoma Pilsbry 1916 and four species in the C. panamensis complex. The latter are C. panamensis Pilsbry, 1916, C. hedgecocki, Pitombo & Burton, 2007, C. alani nom. nov. (formerly C. southwardorum Pitombo & Burton, 2007 and C. newmani sp. nov.. These four species were initially separated by enzyme electrophoresis. They could only be partially separated by DNA bar coding but may be separated using morphological characters.

  6. Natural Image Enhancement Using a Biogeography Based Optimization Enhanced with Blended Migration Operator

    Directory of Open Access Journals (Sweden)

    J. Jasper

    2014-01-01

    Full Text Available This paper addresses a novel and efficient algorithm for solving optimization problem in image processing applications. Image enhancement (IE is one of the complex optimization problems in image processing. The main goal of this paper is to enhance color images such that the eminence of the image is more suitable than the original image from the perceptual viewpoint of human. Traditional methods require prior knowledge of the image to be enhanced, whereas the aim of the proposed biogeography based optimization (BBO enhanced with blended migration operator (BMO algorithm is to maximize the objective function in order to enhance the image contrast by maximizing the parameters like edge intensity, edge information, and entropy. Experimental results are compared with the current state-of-the-art approaches and indicate the superiority of the proposed technique in terms of subjective and objective evaluation.

  7. Bacterial diversity and biogeography in deep-sea sediments of the South Atlantic Ocean

    DEFF Research Database (Denmark)

    Schauer, Regina; Bienhold, Christina; Ramette, Alban

    2010-01-01

    in 1051 sequences. Phylotypes affiliated with Gammaproteobacteria, Deltaproteobacteria and Acidobacteria were present in all three basins. The distribution of these shared phylotypes seemed to be influenced neither by the Walvis Ridge nor by different deep water masses, suggesting a high dispersal......Microbial biogeographic patterns in the deep sea depend on the ability of microorganisms to disperse. One possible limitation to microbial dispersal may be the Walvis Ridge that separates the Antarctic Lower Circumpolar Deep Water from the North Atlantic Deep Water. We examined bacterial...... communities in three basins of the eastern South Atlantic Ocean to determine diversity and biogeography of bacterial communities in deep-sea surface sediments. The analysis of 16S ribosomal RNA (rRNA) gene clone libraries in each basin revealed a high diversity, representing 521 phylotypes with 98% identity...

  8. Diomede Islands, Bering Straight

    Science.gov (United States)

    2008-01-01

    The Diomede Islands consisting of the western island Big Diomede (also known as Imaqliq, Nunarbuk or Ratmanov Island), and the eastern island Little Diomede (also known as Krusenstern Island or Inaliq), are two rocky islands located in the middle of the Bering Strait between Russia and Alaska. The islands are separated by an international border and the International Date Line which is approximately 1.5 km from each island; you can look from Alaska into tomorrow in Russia. At the closest land approach between the United States, which controls Little Diomede, and Russia, which controls Big Diomede, they are 3 km apart. Little Diomede Island constitutes the Alaskan City of Diomede, while Big Diomede Island is Russia's easternmost point. The first European to reach the islands was the Russian explorer Semyon Dezhnev in 1648. The text of the 1867 treaty finalizing the sale of Alaska uses the islands to designate the border between the two nations. The image was acquired July 8, 2000, covers an area of 13.5 x 10.8 km, and is located at 65.8 degrees north latitude, 169 degrees west longitude. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  9. Tales of island tails

    NARCIS (Netherlands)

    Groot, de Alma V.; Oost, Albert P.; Veeneklaas, Roos M.; Lammerts, Evert Jan; Duin, van Willem E.; Wesenbeeck, van Bregje K.

    2016-01-01

    The Frisian islands (Southern North Sea) have extensive island tails, i.e. the entire downdrift side of an island consisting of salt marshes, dunes, beaches and beach plains, and green beaches. Currently, large parts of these tails are ageing and losing dynamics, partly due to human influence.

  10. Rhode Island unemployment

    OpenAIRE

    Leonard Lardaro

    2010-01-01

    How can a state like Rhode Island have such a high unemployment rate? This question has been asked often over the past year, especially since at one point, Rhode Island found itself with the dubious distinction of having the highest unemployment rate in the United States. Following that extreme, Rhode Island seemed to settle into a niche where its rank was third nationally.

  11. Microfluidic Trap Arrays: Passive Sensors for Studying Aquatic Protozoan Ecology and Biogeography

    Science.gov (United States)

    Chau, J. F.; Bouchillon, G.; Shor, L. M.

    2012-12-01

    Microscopic organisms such as bacteria and protozoa are the engine that drives global biogeochemical processes: microbes fix carbon, produce oxygen, mediate nutrient cycling, and break down anthropogenic contaminants. In many habitats, the bacterial community structure and its net production is controlled in a top-down fashion by predation by protozoa. Despite their importance, many researchers have noted a significant gap in our understanding of their diversity, biogeography, and ecosystem function. We developed a microfluidic field sampling and analysis tool to study the biogeography and function of microbial eukaryotes. Microfluidic samplers were created to systematically target the morphology, function, and habitat of different microbial eukaryotes. Features such as channel dimensions, branching angles and radii of curvature were varied to allow organisms to be selected and captured based on cell size, shape, plasticity, and swimming or crawling modalities. We also developed genetic analysis protocols to extract and amplify DNA from a single trapped cell, allowing for molecular identification of trapped species. Results from freshwater sediment and water column deployments confirmed design efficiencies in trapping and concentrating protozoa based on biomass density, allowed for analysis of body plasticity and cell size, and also confirmed the viability of this technology for future real time monitoring of protozoa in aquatic ecosystems. This research offers a radical departure from existing approaches to study microbial eukaryotic communities in the field. Our novel methodology involving trapping, observation and recording of physical characteristics and genetic analysis of single cells allows comparison with bulk samples to place trapped microbes within a function- and habitat-specific context.

  12. Multilocus phylogeny and statistical biogeography clarify the evolutionary history of major lineages of turtles.

    Science.gov (United States)

    Pereira, Anieli G; Sterli, Juliana; Moreira, Filipe R R; Schrago, Carlos G

    2017-08-01

    Despite their complex evolutionary history and the rich fossil record, the higher level phylogeny and historical biogeography of living turtles have not been investigated in a comprehensive and statistical framework. To tackle these issues, we assembled a large molecular dataset, maximizing both taxonomic and gene sampling. As different models provide alternative biogeographical scenarios, we have explicitly tested such hypotheses in order to reconstruct a robust biogeographical history of Testudines. We scanned publicly available databases for nucleotide sequences and composed a dataset comprising 13 loci for 294 living species of Testudines, which accounts for all living genera and 85% of their extant species diversity. Phylogenetic relationships and species divergence times were estimated using a thorough evaluation of fossil information as calibration priors. We then carried out the analysis of historical biogeography of Testudines in a fully statistical framework. Our study recovered the first large-scale phylogeny of turtles with well-supported relationships following the topology proposed by phylogenomic works. Our dating result consistently indicated that the origin of the main clades, Pleurodira and Cryptodira, occurred in the early Jurassic. The phylogenetic and historical biogeographical inferences permitted us to clarify how geological events affected the evolutionary dynamics of crown turtles. For instance, our analyses support the hypothesis that the breakup of Pangaea would have driven the divergence between the cryptodiran and pleurodiran lineages. The reticulated pattern in the ancestral distribution of the cryptodiran lineage suggests a complex biogeographic history for the clade, which was supposedly related to the complex paleogeographic history of Laurasia. On the other hand, the biogeographical history of Pleurodira indicated a tight correlation with the paleogeography of the Gondwanan landmasses. Copyright © 2017 Elsevier Inc. All rights

  13. Waxing and Waning of Forests: Late Quaternary Biogeography of Lake Malawi, Southeast Africa

    Science.gov (United States)

    Ivory, S.; Lézine, A. M.; Vincens, A.; Cohen, A. S.

    2014-12-01

    African ecosystems are at great risk due to climate and land-use change. Despite the status of several of these regions as biodiversity hotspots, long-standing ideas about African ecology and biogeography have been unable to be tested until now due to lack of sufficiently long records. Here, we present the first long, continuous terrestrial record of vegetation from Lake Malawi, East Africa which goes back to the early Late Quaternary, permitting us to investigate changes in physiognomy and forest composition over many transitions. In this record, we observe eight phases of forest expansion and collapse. Although diversity is much greater during forest phases, composition varies little from phase to phase. Very high abundances of afromontane taxa suggest frequent widespread colonization of the lowlands by modern high elevation trees. Although there are clear successional stages within each forest such that turnover is great within a single phase, among forest samples between phases, there is little dissimilarity. Each forest phase is interrupted by rapid decline of arboreal taxa and expansion of semi-arid grasslands or woodlands whose composition varies greatly from phase to phase. The variable composition of the more open phases, all occurring during arid periods, is likely dynamically linked to thresholds in regional hydrology associated with lake level and moisture recycling within the watershed. This vegetation is unlike any found at Malawi today, with assemblages suggesting strong Somali-Masai affinities. Furthermore, nearly all semi-arid assemblages contain small abundances of forest taxa typically growing in areas with wetter edaphic conditions, suggesting that moist lowland gallery forests were present but restricted to waterways during exceptionally arid times. The waxing and waning of forests throughout this interval has important implications for early human biogeography across Africa as well as disturbance regimes that are crucial for the maintenance of

  14. Fossil biogeography: a new model to infer dispersal, extinction and sampling from palaeontological data.

    Science.gov (United States)

    Silvestro, Daniele; Zizka, Alexander; Bacon, Christine D; Cascales-Miñana, Borja; Salamin, Nicolas; Antonelli, Alexandre

    2016-04-05

    Methods in historical biogeography have revolutionized our ability to infer the evolution of ancestral geographical ranges from phylogenies of extant taxa, the rates of dispersals, and biotic connectivity among areas. However, extant taxa are likely to provide limited and potentially biased information about past biogeographic processes, due to extinction, asymmetrical dispersals and variable connectivity among areas. Fossil data hold considerable information about past distribution of lineages, but suffer from largely incomplete sampling. Here we present a new dispersal-extinction-sampling (DES) model, which estimates biogeographic parameters using fossil occurrences instead of phylogenetic trees. The model estimates dispersal and extinction rates while explicitly accounting for the incompleteness of the fossil record. Rates can vary between areas and through time, thus providing the opportunity to assess complex scenarios of biogeographic evolution. We implement the DES model in a Bayesian framework and demonstrate through simulations that it can accurately infer all the relevant parameters. We demonstrate the use of our model by analysing the Cenozoic fossil record of land plants and inferring dispersal and extinction rates across Eurasia and North America. Our results show that biogeographic range evolution is not a time-homogeneous process, as assumed in most phylogenetic analyses, but varies through time and between areas. In our empirical assessment, this is shown by the striking predominance of plant dispersals from Eurasia into North America during the Eocene climatic cooling, followed by a shift in the opposite direction, and finally, a balance in biotic interchange since the middle Miocene. We conclude by discussing the potential of fossil-based analyses to test biogeographic hypotheses and improve phylogenetic methods in historical biogeography. © 2016 The Author(s).

  15. Molecular systematic and historical biogeography of the armored Neotropical catfishes Hypoptopomatinae and Neoplecostominae (Siluriformes: Loricariidae).

    Science.gov (United States)

    Chiachio, Márcio Cesar; Oliveira, Claudio; Montoya-Burgos, Juan I

    2008-11-01

    The Neotropics possess the greatest freshwater fish diversity of the world, rendering the study of their evolutionary history extremely challenging. Loricariidae catfishes are one of the most diverse components of the Neotropical ichthyofauna and despite a long history of classification, major issues still need elucidation. Based on a nuclear gene, we present a robust phylogeny of two former loricariid subfamilies: Hypoptopomatinae and Neoplecostominae. Our results show that Neoplecostominae is nested within Hypoptopomatinae, and is the sister group to the former Otothyrini tribe. According to our results, supplemented by morphological observations, we erect two new subfamilies, the Otothyrinae and a new Hypoptopomatinae, and modify the Neoplecostominae by including the genus Pseudotocinclus. The uncovered evolutionary relationships allow a detailed analysis of their historical biogeography. We tested two Dispersal-Extinction-Cladogenesis models for inferring the distribution range evolution of the new subfamilies, and show that the model having no constrains performs better than a model constraining long-range dispersal. The Maximum Likelihood reconstructions of ancestral ranges showed a marked division between the Amazonian origin of the Hypoptopomatinae and the eastern coastal Brazil+Upper Paraná origin of the Neoplecostominae and Otothyrinae. Markedly few instances of dispersal across the border separating the Amazon basin and the Paraná-Paraguay+eastern coastal Brazil+Uruguay were reconstructed. This result is in clear contrast with the historical biogeography of many Neotropical fishes, including other Loricariidae. Part of the dispersal limitation may be explained by divergent ecological specialization: lowland rivers versus mountain streams habitats. Moreover, because most species of the new subfamilies are small, we hypothesize that body size-related effects might limit their dispersal, like predation and energetic cost to migration. Finally

  16. The taxonomy, biogeography and conservation of the myrmecophilous Chrysoritis butterflies (Lepidoptera: Lycaenidae in South Africa

    Directory of Open Access Journals (Sweden)

    R.F. Terblanche

    2003-12-01

    Full Text Available The relevance and integration of scientific knowledge to conservation management of the locally popular and highly endemic butterfly genus Chrysoritis are investigated within the research fields of taxonomy and biogeography. The butterfly genus Chrysoritis contains at least 41 species endemic to South Africa. The taxonomy of Chrysoritis has reached a state where revisions could easily result in a plethora of names between “lumping and splitting”. In practice, the state of the taxonomy of these butterflies on species level may alter their conservation priority. The two most species rich species groups in Chrysoritis have different centres of endemism, however, a butterfly atlas becomes a necessity to reveal more about their biogeography. There is an absence of butterfly species lists in many of our National Parks and Nature Reserves. Legislation should facilitate rather than limit the valuable role of the amateur lepidopterist to add distribution records. In turn, the amateur lepidopterists should adapt and make an effort to explore unknown localities, apart from monitoring butterflies at their well-known localities. The red listing of localised butterflies in South Africa, including a number of Chrysoritis species, is in need of an urgent review in the light of the most recent IUCN categories. A species such as Chrysoritis dicksoni should be protected by law - but at its known localities. The scenario that real conservation action is only needed if the last known locality of a butterfly is threatened, should be abolished. A paradigm shift to conserve the metapopulations of the highly endemic Chrysoritis genus and not merely a few of its species as items that appear on lists, seems necessary.

  17. Allopatric speciation of Meteterakis (Heterakoidea: Heterakidae), a highly dispersible parasitic nematode, in the East Asian islands.

    Science.gov (United States)

    Sata, Naoya

    2018-04-25

    To clarify how the species diversity of highly dispersible parasites has developed, molecular phylogenetic analyses of Meteterakis spp., multi-host endoparasitic nematodes of reptiles and amphibians from the East Asian islands, were conducted. The results demonstrated the existence of two major clades, the J- and A-groups, with exclusive geographic ranges that are discordant with the host faunal province. However, diversification within the J-group was concordant with the host biogeography and suggested co-divergence of this group with vicariance of the host fauna. In contrast, the phylogenetic pattern within the A-group was discordant with host biogeography and implied diversification by repeated colonization. In addition, the mosaic distribution pattern of a J-group and an A-group species in the Japanese Archipelago, along with comparison of population genetic parameters and the genetic distance from their closest relatives, suggested the initial occurrence of a J-group lineage followed by exclusion in the western part of this region caused by invasion of an A-group lineage. Thus, the present study suggested that the species diversity of highly dispersible parasites including Meteterakis is formed not only by co-divergence with host faunal vicariance but also by peripatric speciation and exclusive interactions between species. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Revisiting tourist behavior via destination brand worldness

    Directory of Open Access Journals (Sweden)

    Murat Kayak

    2016-11-01

    Full Text Available Taking tourists’ perspective rather than destination offerings as its core concept, this study introduces “perceived destination brand worldness” as a variable. Perceived destination brand worldness is defined as the positive perception that a tourist has of a country that is visited by tourists from all over the world. Then, the relationship between perceived destination brand worldness and intention to revisit is analyzed using partial least squares regression. This empirical study selects Taiwanese tourists as its sample, and the results show that perceived destination brand worldness is a direct predictor of intention to revisit. In light of these empirical findings and observations, practical and theoretical implications are discussed.

  19. The "island rule" and deep-sea gastropods: re-examining the evidence.

    Directory of Open Access Journals (Sweden)

    John J Welch

    2010-01-01

    Full Text Available One of the most intriguing patterns in mammalian biogeography is the "island rule", which states that colonising species have a tendency to converge in body size, with larger species evolving decreased sizes and smaller species increased sizes. It has recently been suggested that an analogous pattern holds for the colonisation of the deep-sea benthos by marine Gastropoda. In particular, a pioneering study showed that gastropods from the Western Atlantic showed the same graded trend from dwarfism to gigantism that is evident in island endemic mammals. However, subsequent to the publication of the gastropod study, the standard tests of the island rule have been shown to yield false positives at a very high rate, leaving the result open to doubt.The evolution of gastropod body size in the deep sea is reexamined. Using an extended and updated data set, and improved statistical methods, it is shown that some results of the previous study may have been artifactual, but that its central conclusion is robust. It is further shown that the effect is not restricted to a single gastropod clade, that its strength increases markedly with depth, but that it applies even in the mesopelagic zone.The replication of the island rule in a distant taxonomic group and a partially analogous ecological situation could help to uncover the causes of the patterns observed--which are currently much disputed. The gastropod pattern is evident at intermediate depths, and so cannot be attributed to the unique features of abyssal ecology.

  20. Bacterial biogeography influenced by shelf-basin exchange in the Arctic surface sediment at the Chukchi Borderland.

    Science.gov (United States)

    Han, Dukki; Nam, Seung-Il; Ha, Ho Kyung; Kim, Hyoungjun; Sadowsky, Michael J; Lee, Yoo Kyung; Hur, Hor-Gil

    2016-02-01

    It has been known that continental shelves around the Arctic Ocean play a major role in the ventilation of the deep basins as a consequence of shelf-basin exchange. In the present study, we found that bacterial assemblage of the surface sediment was different from that of seawater while seawater harboured local bacterial assemblages in response to the Arctic hydrography. This finding suggests that the Arctic seafloor sediments may have distinctive bacterial biogeography. Moreover, the distribution of bacterial assemblages and physicochemical properties in surface sediments changed gradually from the Arctic continental shelf to deep-sea basin. Based on the results, bacterial biogeography in the Arctic seafloor sediments may be influenced by winnowing and re-deposition of surface sediments through the sediment gravity flow. The present study offers a deeper understanding of shelf convection and its role for the construction of bacterial assemblages in the Arctic Ocean. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. The biogeography of threatened insular iguanas and opportunities for invasive vertebrate management

    Science.gov (United States)

    Tershy, Bernie R.; Newton, Kelly M.; Spatz, Dena R.; Swinnerton, Kirsty; Iverson, John B.; Fisher, Robert N.; Harlow, Peter S.; Holmes, Nick D.; Croll, Donald A.; Iverson, J.B.; Grant, T. D.; Knapp, C. R.; Pasachnik, S. A.

    2016-01-01

    Iguanas are a particularly threatened group of reptiles, with 61% of species at risk of extinction. Primary threats to iguanas include habitat loss, direct and indirect impacts by invasive vertebrates, overexploitation, and human disturbance. As conspicuous, charismatic vertebrates, iguanas also represent excellent flagships for biodiversity conservation. To assist planning for invasive vertebrate management and thus benefit threatened iguana recovery, we identified all islands with known extant or extirpated populations of Critically Endangered and Endangered insular iguana taxa as recognized by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. For each island, we determined total area, sovereignty, the presence of invasive alien vertebrates, and human population. For the 23 taxa of threatened insular iguanas we identified 230 populations, of which iguanas were extant on 185 islands and extirpated from 45 islands. Twenty-one iguana taxa (91% of all threatened insular iguana taxa) occurred on at least one island with invasive vertebrates present; 16 taxa had 100% of their population(s) on islands with invasive vertebrates present. Rodents, cats, ungulates, and dogs were the most common invasive vertebrates. We discuss biosecurity, eradication, and control of invasive vertebrates to benefit iguana recovery: (1) on islands already free of invasive vertebrates; (2) on islands with high iguana endemicity; and (3) for species and subspecies with small total populations occurring across multiple small islands. Our analyses provide an important first step toward understanding how invasive vertebrate management can be planned effectively to benefit threatened insular iguanas.

  2. An ant genus-group (Prenolepis) illuminates the biogeography and drivers of insect diversification in the Indo-Pacific

    Czech Academy of Sciences Publication Activity Database

    Matos Maravi, Pavel F.; Clouse, R. M.; Sarnat, E. M.; Economo, E. P.; LaPolla, J. S.; Borovanská, Michaela; Rabeling, C.; Czekanski-Moir, J.; Latumahina, F.; Wilson, E. O.; Janda, Milan

    2018-01-01

    Roč. 123, JUN 01 (2018), s. 16-25 ISSN 1055-7903 R&D Projects: GA ČR GB14-36098G Grant - others:GA JU(CZ) 156/2013/P; GA JU(CZ) 152/2016/P Institutional support: RVO:60077344 Keywords : biogeography * diversification rate * ecological shift Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 4.419, year: 2016 https://www.sciencedirect.com/science/article/pii/S1055790316303414

  3. The diversity and biogeography of the communities of Actinobacteria in the forelands of glaciers at a continental scale

    Science.gov (United States)

    Zhang, Binglin; Wu, Xiukun; Zhang, Gaosen; Li, Shuyan; Zhang, Wei; Chen, Ximing; Sun, Likun; Zhang, Baogui; Liu, Guangxiu; Chen, Tuo

    2016-05-01

    Glacier forelands, where the initially exposed area is unvegetated with minimal human influence, are an ideal place for research on the distributions and biogeography of microbial communities. Actinobacteria produce many bioactive substances and have important roles in soil development and biogeochemical cycling. However, little is known about the distribution and biogeography of Actinobacteria in glacier forelands. Therefore, we investigated the patterns of diversity and the biogeography of actinobacterial communities of the inhabited forefields of 5 glaciers in China. Of the bacteria, the mean relative abundance of Actinobacteria was 13.1%, and 6 classes were identified in the phylum Actinobacteria. The dominant class was Actinobacteria (57%), which was followed in abundance by Acidimicrobiia (19%) and Thermoleophilia (19%). When combined, the relative abundance of the other three classes, the MB-A2-108, Nitriliruptoria and Rubrobacteria, was only 2.4%. A biogeographic pattern in the forelands of the 5 glaciers in China was not detected for actinobacterial communities. Compared with 7 other actinobacterial communities found in the forelands of glaciers globally, those in the Southern Hemisphere were significantly different from those in the Northern Hemisphere. Moreover, the communities were significantly different on the separate continents of the Northern Hemisphere. The dissimilarity of the actinobacterial communities increased with geographic distance (r = 0.428, p = 0.0003). Because of environmental factors, the effect of geography was clear when the distance exceeded a certain continent-level threshold. With the analysis of indicator species, we found that each genus had a geographic characteristic, which could explain why the communities with greater diversity were more strongly affected by biogeography.

  4. Leukemia and ionizing radiation revisited

    Energy Technology Data Exchange (ETDEWEB)

    Cuttler, J.M. [Cuttler & Associates Inc., Vaughan, Ontario (Canada); Welsh, J.S. [Loyola University-Chicago, Dept. or Radiation Oncology, Stritch School of Medicine, Maywood, Illinois (United States)

    2016-03-15

    A world-wide radiation health scare was created in the late 19508 to stop the testing of atomic bombs and block the development of nuclear energy. In spite of the large amount of evidence that contradicts the cancer predictions, this fear continues. It impairs the use of low radiation doses in medical diagnostic imaging and radiation therapy. This brief article revisits the second of two key studies, which revolutionized radiation protection, and identifies a serious error that was missed. This error in analyzing the leukemia incidence among the 195,000 survivors, in the combined exposed populations of Hiroshima and Nagasaki, invalidates use of the LNT model for assessing the risk of cancer from ionizing radiation. The threshold acute dose for radiation-induced leukemia, based on about 96,800 humans, is identified to be about 50 rem, or 0.5 Sv. It is reasonable to expect that the thresholds for other cancer types are higher than this level. No predictions or hints of excess cancer risk (or any other health risk) should be made for an acute exposure below this value until there is scientific evidence to support the LNT hypothesis. (author)

  5. Individualist Biocentrism vs. Holism Revisited

    Directory of Open Access Journals (Sweden)

    Katie McShane

    2014-06-01

    Full Text Available While holist views such as ecocentrism have considerable intuitive appeal, arguing for the moral considerability of ecological wholes such as ecosystems has turned out to be a very difficult task. In the environmental ethics literature, individualist biocentrists have persuasively argued that individual organisms—but not ecological wholes—are properly regarded as having a good of their own . In this paper, I revisit those arguments and contend that they are fatally flawed. The paper proceeds in five parts. First, I consider some problems brought about by climate change for environmental conservation strategies and argue that these problems give us good pragmatic reasons to want a better account of the welfare of ecological wholes. Second, I describe the theoretical assumptions from normative ethics that form the background of the arguments against holism. Third, I review the arguments given by individualist biocentrists in favour of individualism over holism. Fourth, I review recent work in the philosophy of biology on the units of selection problem, work in medicine on the human biome, and work in evolutionary biology on epigenetics and endogenous viral elements. I show how these developments undermine both the individualist arguments described above as well as the distinction between individuals and wholes as it has been understood by individualists. Finally, I consider five possible theoretical responses to these problems.

  6. Revisiting the safety of aspartame.

    Science.gov (United States)

    Choudhary, Arbind Kumar; Pretorius, Etheresia

    2017-09-01

    Aspartame is a synthetic dipeptide artificial sweetener, frequently used in foods, medications, and beverages, notably carbonated and powdered soft drinks. Since 1981, when aspartame was first approved by the US Food and Drug Administration, researchers have debated both its recommended safe dosage (40 mg/kg/d) and its general safety to organ systems. This review examines papers published between 2000 and 2016 on both the safe dosage and higher-than-recommended dosages and presents a concise synthesis of current trends. Data on the safe aspartame dosage are controversial, and the literature suggests there are potential side effects associated with aspartame consumption. Since aspartame consumption is on the rise, the safety of this sweetener should be revisited. Most of the literature available on the safety of aspartame is included in this review. Safety studies are based primarily on animal models, as data from human studies are limited. The existing animal studies and the limited human studies suggest that aspartame and its metabolites, whether consumed in quantities significantly higher than the recommended safe dosage or within recommended safe levels, may disrupt the oxidant/antioxidant balance, induce oxidative stress, and damage cell membrane integrity, potentially affecting a variety of cells and tissues and causing a deregulation of cellular function, ultimately leading to systemic inflammation. © The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  7. Neutrino assisted GUT baryogenesis revisited

    Science.gov (United States)

    Huang, Wei-Chih; Päs, Heinrich; Zeißner, Sinan

    2018-03-01

    Many grand unified theory (GUT) models conserve the difference between the baryon and lepton number, B -L . These models can create baryon and lepton asymmetries from heavy Higgs or gauge boson decays with B +L ≠0 but with B -L =0 . Since the sphaleron processes violate B +L , such GUT-generated asymmetries will finally be washed out completely, making GUT baryogenesis scenarios incapable of reproducing the observed baryon asymmetry of the Universe. In this work, we revisit the idea to revive GUT baryogenesis, proposed by Fukugita and Yanagida, where right-handed neutrinos erase the lepton asymmetry before the sphaleron processes can significantly wash out the original B +L asymmetry, and in this way one can prevent a total washout of the initial baryon asymmetry. By solving the Boltzmann equations numerically for baryon and lepton asymmetries in a simplified 1 +1 flavor scenario, we can confirm the results of the original work. We further generalize the analysis to a more realistic scenario of three active and two right-handed neutrinos to highlight flavor effects of the right-handed neutrinos. Large regions in the parameter space of the Yukawa coupling and the right-handed neutrino mass featuring successful baryogenesis are identified.

  8. Paradise Islands? Island States and Environmental Performance

    Directory of Open Access Journals (Sweden)

    Sverker C. Jagers

    2016-03-01

    Full Text Available Island states have been shown to outperform continental states on a number of large-scale coordination-related outcomes, such as levels of democracy and institutional quality. The argument developed and tested in this article contends that the same kind of logic may apply to islands’ environmental performance, too. However, the empirical analysis shows mixed results. Among the 105 environmental outcomes that we analyzed, being an island only has a positive impact on 20 of them. For example, island states tend to outcompete continental states with respect to several indicators related to water quality but not in aspects related to biodiversity, protected areas, or environmental regulations. In addition, the causal factors previously suggested to make islands outperform continental states in terms of coordination have weak explanatory power in predicting islands’ environmental performance. We conclude the paper by discussing how these interesting findings can be further explored.

  9. Revisiting Hansen Solubility Parameters by Including Thermodynamics

    NARCIS (Netherlands)

    Louwerse, Manuel J; Fernández-Maldonado, Ana María; Rousseau, Simon; Moreau-Masselon, Chloe; Roux, Bernard; Rothenberg, Gadi

    2017-01-01

    The Hansen solubility parameter approach is revisited by implementing the thermodynamics of dissolution and mixing. Hansen's pragmatic approach has earned its spurs in predicting solvents for polymer solutions, but for molecular solutes improvements are needed. By going into the details of entropy

  10. The Future of Engineering Education--Revisited

    Science.gov (United States)

    Wankat, Phillip C.; Bullard, Lisa G.

    2016-01-01

    This paper revisits the landmark CEE series, "The Future of Engineering Education," published in 2000 (available free in the CEE archives on the internet) to examine the predictions made in the original paper as well as the tools and approaches documented. Most of the advice offered in the original series remains current. Despite new…

  11. Revisiting the formal foundation of Probabilistic Databases

    NARCIS (Netherlands)

    Wanders, B.; van Keulen, Maurice

    2015-01-01

    One of the core problems in soft computing is dealing with uncertainty in data. In this paper, we revisit the formal foundation of a class of probabilistic databases with the purpose to (1) obtain data model independence, (2) separate metadata on uncertainty and probabilities from the raw data, (3)

  12. Revisiting Weak Simulation for Substochastic Markov Chains

    DEFF Research Database (Denmark)

    Jansen, David N.; Song, Lei; Zhang, Lijun

    2013-01-01

    of the logic PCTL\\x, and its completeness was conjectured. We revisit this result and show that soundness does not hold in general, but only for Markov chains without divergence. It is refuted for some systems with substochastic distributions. Moreover, we provide a counterexample to completeness...

  13. Coccolithophorids in polar waters: Wigwamma spp. revisited

    DEFF Research Database (Denmark)

    Thomsen, Helge Abildhauge; Østergaard, Jette B.; Heldal, Mikal

    2013-01-01

    A contingent of weakly calcified coccolithophorid genera and species were described from polar regions almost 40 years ago. In the interim period a few additional findings have been reported enlarging the realm of some of the species. The genus Wigwamma is revisited here with the purpose of provi...... appearance of the coccolith armour of the cell...

  14. The Faraday effect revisited: General theory

    DEFF Research Database (Denmark)

    Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm

    2006-01-01

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. At zero temperature and zero frequency...

  15. The Faraday effect revisited: General theory

    DEFF Research Database (Denmark)

    Cornean, Horia Decebal; Nenciu, Gheorghe; Pedersen, Thomas Garm

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse...

  16. Mola'a Revisited: Reef Panpipes

    DEFF Research Database (Denmark)

    2017-01-01

    The first main shoot for the Reef Islands Ethnographic Film Series in the Solomon Islands, in 1996, was seriously affected by the un- expected death of one of the main characters and partners in the project, Alfred Melotu, the paramount chief of the Aiwoo-speaking people on the island of Ngasinue...

  17. eWOM, Revisit Intention, Destination Trust and Gender

    OpenAIRE

    Abubakar, Abubakar Mohammed; Ilkan, Mustafa; Al-Tal, Raad Meshall; Eluwole, Kayode

    2017-01-01

    This article investigates the impact of eWOM on intention to revisit and destination trust, and the moderating role of gender in medical tourism industry. Result from structural equation modeling (n=240) suggests the following: (1) that eWOM influences intention to revisit and destination trust; (2) that destination trust influences intention to revisit; (3) that the impact of eWOM on intention to revisit is about 1.3 times higher in men; (4) that the impact of eWOM on destination trust is ab...

  18. Tanzania - Mafia Island Airport

    Data.gov (United States)

    Millennium Challenge Corporation — The evaluation design and subsequent data gathering activities will address the following key research questions: a) Has the Mafia Island Airport Upgrade Project...

  19. Molecular phylogenetics and historical biogeography of the west-palearctic common toads (Bufo bufo species complex).

    Science.gov (United States)

    Garcia-Porta, J; Litvinchuk, S N; Crochet, P A; Romano, A; Geniez, P H; Lo-Valvo, M; Lymberakis, P; Carranza, S

    2012-04-01

    In most pan-Eurasiatic species complexes, two phenomena have been traditionally considered key processes of their cladogenesis and biogeography. First, it is hypothesized that the origin and development of the Central Asian Deserts generated a biogeographic barrier that fragmented past continuous distributions in Eastern and Western domains. Second, Pleistocene glaciations have been proposed as the main process driving the regional diversification within each of these domains. The European common toad and its closest relatives provide an interesting opportunity to examine the relative contributions of these paleogeographic and paleoclimatic events to the phylogeny and biogeography of a widespread Eurasiatic group. We investigate this issue by applying a multiproxy approach combining information from molecular phylogenies, a multiple correspondence analysis of allozyme data and species distribution models. Our study includes 304 specimens from 164 populations, covering most of the distributional range of the Bufo bufo species complex in the Western Palearctic. The phylogenies (ML and Bayesian analyses) were based on a total of 1988 bp of mitochondrial DNA encompassing three genes (tRNAval, 16S and ND1). A dataset with 173 species of the family Bufonidae was assembled to estimate the separation of the two pan-Eurasiatic species complexes of Bufo and to date the main biogeographic events within the Bufo bufo species complex. The allozyme study included sixteen protein systems, corresponding to 21 presumptive loci. Finally, the distribution models were based on maximum entropy. Our distribution models show that Eastern and Western species complexes are greatly isolated by the Central Asian Deserts, and our dating estimates place this divergence during the Middle Miocene, a moment in which different sources of evidence document a major upturn of the aridification rate of Central Asia. This climate-driven process likely separated the Eastern and Western species. At the

  20. Roles of effective helical ripple rates in nonlinear stability of externally induced magnetic islands

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Seiya, E-mail: n-seiya@kobe-kosen.ac.jp [Kobe City College of Technology, Kobe, Hyogo 651-2194 (Japan)

    2015-02-15

    Magnetic islands are externally produced by resonant magnetic perturbations (RMPs) in toroidal plasmas. Spontaneous annihilation of RMP-induced magnetic islands called self-healing has been observed in helical systems. A possible mechanism of the self-healing is shielding of RMP penetration by helical ripple-induced neoclassical flows, which give rise to neoclassical viscous torques. In this study, effective helical ripple rates in multi-helicity helical systems are revisited, and a multi-helicity effect on the self-healing is investigated, based on a theoretical model of rotating magnetic islands. It is confirmed that effective helical ripple rates are sensitive to magnetic axis positions. It is newly found that self-healing thresholds also strongly depend on magnetic axis positions, which is due to dependence of neoclassical viscous torques on effective helical ripple rates.

  1. Plant compartment and biogeography affect microbiome composition in cultivated and native Agave species.

    Science.gov (United States)

    Coleman-Derr, Devin; Desgarennes, Damaris; Fonseca-Garcia, Citlali; Gross, Stephen; Clingenpeel, Scott; Woyke, Tanja; North, Gretchen; Visel, Axel; Partida-Martinez, Laila P; Tringe, Susannah G

    2016-01-01

    Desert plants are hypothesized to survive the environmental stress inherent to these regions in part thanks to symbioses with microorganisms, and yet these microbial species, the communities they form, and the forces that influence them are poorly understood. Here we report the first comprehensive investigation of the microbial communities associated with species of Agave, which are native to semiarid and arid regions of Central and North America and are emerging as biofuel feedstocks. We examined prokaryotic and fungal communities in the rhizosphere, phyllosphere, leaf and root endosphere, as well as proximal and distal soil samples from cultivated and native agaves, through Illumina amplicon sequencing. Phylogenetic profiling revealed that the composition of prokaryotic communities was primarily determined by the plant compartment, whereas the composition of fungal communities was mainly influenced by the biogeography of the host species. Cultivated A. tequilana exhibited lower levels of prokaryotic diversity compared with native agaves, although no differences in microbial diversity were found in the endosphere. Agaves shared core prokaryotic and fungal taxa known to promote plant growth and confer tolerance to abiotic stress, which suggests common principles underpinning Agave-microbe interactions. No claim to US Government works. New Phytologist © 2015 New Phytologist Trust.

  2. Biogeography of Coptis Salisb. (Ranunculales, Ranunculaceae, Coptidoideae), an Eastern Asian and North American genus.

    Science.gov (United States)

    Xiang, Kun-Li; Erst, Andrey S; Xiang, Xiao-Guo; Jabbour, Florian; Wang, Wei

    2018-05-24

    Numerous studies have favored dispersal (colonization) over vicariance (past fragmentation) events to explain eastern Asian-North American distribution patterns. In plants, however the disjunction between eastern Asia and western North America has been rarely examined using the integration of phylogenetic, molecular dating, and biogeographical methods. Meanwhile, the biogeographic patterns within eastern Asia remain poorly understood. The goldthread genus Coptis Salisb. includes 15 species disjunctly distributed in North America, Japan, mainland China, and Taiwan. We present a dated phylogeny for Coptis under the optimal clock model and infer its historical biogeography by comparing different biogeographic models. The split of Coptis and Xanthorhiza Marshall occurred in the middle Miocene (ca. 15.47 Ma). Coptis started their diversification in the early late Miocene (ca. 9.55 Ma). A late Miocene vicariance event resulted in the eastern Asian and western North American disjunction in the genus. Within eastern Asia, dispersals from mainland Asia to Japan and from Japan to Taiwan occurred at ca. 4.85 Ma and at ca. 1.34 Ma, respectively. Our analyses provide evidence that both vicariance and dispersal events have played important roles in shaping the current distribution and endemism of Coptis, likely resulting from eustatic sea-level changes, mountain formation processes and an increasing drier and cooler climate from the middle Miocene onwards.

  3. Phylogenetic diversity and biogeography of the Mamiellophyceae lineage of eukaryotic phytoplankton across the oceans.

    Science.gov (United States)

    Monier, Adam; Worden, Alexandra Z; Richards, Thomas A

    2016-08-01

    High-throughput diversity amplicon sequencing of marine microbial samples has revealed that members of the Mamiellophyceae lineage are successful phytoplankton in many oceanic habitats. Indeed, these eukaryotic green algae can dominate the picoplanktonic biomass, however, given the broad expanses of the oceans, their geographical distributions and the phylogenetic diversity of some groups remain poorly characterized. As these algae play a foundational role in marine food webs, it is crucial to assess their global distribution in order to better predict potential changes in abundance and community structure. To this end, we analyzed the V9-18S small subunit rDNA sequences deposited from the Tara Oceans expedition to evaluate the diversity and biogeography of these phytoplankton. Our results show that the phylogenetic composition of Mamiellophyceae communities is in part determined by geographical provenance, and do not appear to be influenced - in the samples recovered - by water depth, at least at the resolution possible with the V9-18S. Phylogenetic classification of Mamiellophyceae sequences revealed that the Dolichomastigales order encompasses more sequence diversity than other orders in this lineage. These results indicate that a large fraction of the Mamiellophyceae diversity has been hitherto overlooked, likely because of a combination of size fraction, sequencing and geographical limitations. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Design of SVC Controller Based on Improved Biogeography-Based Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Feifei Dong

    2014-01-01

    Full Text Available Considering that common subsynchronous resonance controllers cannot adapt to the characteristics of the time-varying and nonlinear behavior of a power system, the cosine migration model, the improved migration operator, and the mutative scale of chaos and Cauchy mutation strategy are introduced into an improved biogeography-based optimization (IBBO algorithm in order to design an optimal subsynchronous damping controller based on the mechanism of suppressing SSR by static var compensator (SVC. The effectiveness of the improved controller is verified by eigenvalue analysis and electromagnetic simulations. The simulation results of Jinjie plant indicate that the subsynchronous damping controller optimized by the IBBO algorithm can remarkably improve the damping of torsional modes and thus effectively depress SSR, and ensure the safety and stability of units and power grid operation. Moreover, the IBBO algorithm has the merits of a faster searching speed and higher searching accuracy in seeking the optimal control parameters over traditional algorithms, such as BBO algorithm, PSO algorithm, and GA algorithm.

  5. Diversity and biogeography of frogs in the genus Amnirana (Anura: Ranidae) across sub-Saharan Africa.

    Science.gov (United States)

    Jongsma, Gregory F M; Barej, Michael F; Barratt, Christopher D; Burger, Marius; Conradie, Werner; Ernst, Raffael; Greenbaum, Eli; Hirschfeld, Mareike; Leaché, Adam D; Penner, Johannes; Portik, Daniel M; Zassi-Boulou, Ange-Ghislain; Rödel, Mark-Oliver; Blackburn, David C

    2018-03-01

    Frogs in the genus Amnirana (family Ranidae) are widely distributed across sub-Saharan Africa and present a model system for exploring the relationship between diversification and geography across the continent. Using multiple loci from the mitochondrial (16S) and nuclear genomes (DISP2, FICD, KIAA2013, REV3L), we generated a strongly supported species-level phylogeny that provides insights into the continental biogeography of African species of Amnirana, which form a monophyletic group within the genus. Species delimitation analyses suggest that there may be as many as seven additional species of Amnirana in Africa. The biogeographic history of Amnirana is marked by several dispersal and vicariance events, including dispersal from the Lower Guinean Forest into the Congo Basin. In addition, phylogeographic patterns within two widespread species, A. albolabris and A. galamensis, reveal undescribed cryptic diversity. Populations assigned to A. albolabris in western Africa are more closely related to A. fonensis and require recognition as a distinct species. Our analyses reveal that the Lower and Upper Guinean Forest regions served as important centers of interspecific and intraspecific diversifications for Amnirana. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Biogeography and ecology of Cetraria aculeata, a widely distributed lichen with a bipolar distribution

    Directory of Open Access Journals (Sweden)

    Christian Printzen

    2013-04-01

    Full Text Available Ecological and historical biogeography of lichens have rarely been studied in a concerted effort, but both aspects have to be taken into consideration when explaining the distributional patterns of species. This review summarizes, partly preliminary, results from a series of studies on phylogeography, ecophysiology and symbiotic interactions of the lichen Cetraria aculeata. This species is not only widespread but also occupies a very wide ecological niche. Evidence suggests that Cetraria aculeata has evolved and diversified in the Northern Hemisphere and colonised the Southern Hemisphere from there. Genetic isolation of populations indicates the absence of ongoing long range dispersal and genetic exchange between geographically isolated populations. We observe a hitherto unrecognized genetic diversity that may indicate ecotypic differentiation and speciation processes. Mediterranean and Polar populations differ not only genetically, but also in ecophysiological properties. Ongoing common garden experiments will have to show whether genetically fixed adaptation or acclimation is responsible for these differences. The genetic structure of the photobiont is best explained by climatic differences between localities, but co-dispersal with the mycobiont plays an important role as well. Taken together, these results indicate that a photobiont switch in the past enabled C. aculeata to widen its ecological niche, with subsequent genetic isolation of populations. Photobiont switches may play a crucial role in speciation processes of lichens. A combination of ecophysiological and phylogeographic studies with experimental approaches is necessary to better understand the reaction of lichens to changing environmental conditions.

  7. Planning of motion strategy for hexapod robot using biogeography based optimization

    Directory of Open Access Journals (Sweden)

    Hayder Mahdi Abdulridha

    2017-08-01

    Full Text Available The necessity to utilize the usage of the robot cannot be denied since there are a lot of natural disasters occur around the world, the robot can reach places where humans cannot reach. Hexapod robotic is one of the robots utilized in this case due to its balance and versatility at some stage in the movement on any kind of floor. In this project the explanation of using software and hardware Arduino microcontroller is used to control of such a hexapod. The output signal from Arduino for controlling leg's joint angular position such as a pulse called Pulse Width Modulation (PWM. Also Arduino programmed to create the sequence of motion for six legs. The second part of project is about controlling hexapod to avoid hitches and tracking the wall by using PID controller. Tuning of the PID processes based on Biogeography Based Optimization(BBO need to keep the connection between PC and hexapod, because the BBO was written by Matlab. The experimental results using BBO to optimize the PID controller parameters of hexapod robot show the efficiency of this technique in the adaptation of controller.

  8. Advancing global marine biogeography research with open-source GIS software and cloud-computing

    Science.gov (United States)

    Fujioka, Ei; Vanden Berghe, Edward; Donnelly, Ben; Castillo, Julio; Cleary, Jesse; Holmes, Chris; McKnight, Sean; Halpin, patrick

    2012-01-01

    Across many scientific domains, the ability to aggregate disparate datasets enables more meaningful global analyses. Within marine biology, the Census of Marine Life served as the catalyst for such a global data aggregation effort. Under the Census framework, the Ocean Biogeographic Information System was established to coordinate an unprecedented aggregation of global marine biogeography data. The OBIS data system now contains 31.3 million observations, freely accessible through a geospatial portal. The challenges of storing, querying, disseminating, and mapping a global data collection of this complexity and magnitude are significant. In the face of declining performance and expanding feature requests, a redevelopment of the OBIS data system was undertaken. Following an Open Source philosophy, the OBIS technology stack was rebuilt using PostgreSQL, PostGIS, GeoServer and OpenLayers. This approach has markedly improved the performance and online user experience while maintaining a standards-compliant and interoperable framework. Due to the distributed nature of the project and increasing needs for storage, scalability and deployment flexibility, the entire hardware and software stack was built on a Cloud Computing environment. The flexibility of the platform, combined with the power of the application stack, enabled rapid re-development of the OBIS infrastructure, and ensured complete standards-compliance.

  9. Phylogeny and Historical Biogeography of Acer I-Study History of the Infrageneric Classification(1

    Directory of Open Access Journals (Sweden)

    Shing-Fan Huang

    2002-09-01

    Full Text Available Historical biogeography is a study of taxa in time and space including their origin, migration and diversification. This kind of study requires fossil data and an understanding of phylogenetic relationships. These requirements make Acer a good model to study because Acer 1 has a relatively complete fossil record, 2 contains many species, 3 is a major northern temperate floristic element, and 4 is well known. Because fossils are only confidently assigned to section or species group, section as a unit is suitable for tracing evolutionary history of Acer. However, the circumscription of section of Acer is different to each classification through the long history of studies. This work reviews and summarizes the studying history of Acer. Delendick in 1981concluded that the system of Ogata in 1967 and that of Jong in 1976 were superior to others except that most Jong’s series should be raised to section. This work, therefore, follows Delendick’s delineation of section except Distyla and Parviflora, which are combined as Parviflora, to elucidate the development of the circumscription of section based on the system of Pax in 1885 and 1886, Pojarkova in 1933, Momotani in 1962, Fang in 1966, Ogata in 1967, Murray in 1970, Jong in 1976, Delendick in 1990 and Xu in 1996.

  10. Cognitive radio adaptation for power consumption minimization using biogeography-based optimization

    International Nuclear Information System (INIS)

    Qi Pei-Han; Zheng Shi-Lian; Yang Xiao-Niu; Zhao Zhi-Jin

    2016-01-01

    Adaptation is one of the key capabilities of cognitive radio, which focuses on how to adjust the radio parameters to optimize the system performance based on the knowledge of the radio environment and its capability and characteristics. In this paper, we consider the cognitive radio adaptation problem for power consumption minimization. The problem is formulated as a constrained power consumption minimization problem, and the biogeography-based optimization (BBO) is introduced to solve this optimization problem. A novel habitat suitability index (HSI) evaluation mechanism is proposed, in which both the power consumption minimization objective and the quality of services (QoS) constraints are taken into account. The results show that under different QoS requirement settings corresponding to different types of services, the algorithm can minimize power consumption while still maintaining the QoS requirements. Comparison with particle swarm optimization (PSO) and cat swarm optimization (CSO) reveals that BBO works better, especially at the early stage of the search, which means that the BBO is a better choice for real-time applications. (paper)

  11. Metacommunity versus biogeography: a case study of two groups of neotropical vegetation-dwelling arthropods.

    Directory of Open Access Journals (Sweden)

    Thiago Gonçalves-Souza

    Full Text Available Biogeography and metacommunity ecology provide two different perspectives on species diversity. Both are spatial in nature but their spatial scales do not necessarily match. With recent boom of metacommunity studies, we see an increasing need for clear discrimination of spatial scales relevant for both perspectives. This discrimination is a necessary prerequisite for improved understanding of ecological phenomena across scales. Here we provide a case study to illustrate some spatial scale-dependent concepts in recent metacommunity studies and identify potential pitfalls. We presented here the diversity patterns of Neotropical lepidopterans and spiders viewed both from metacommunity and biogeographical perspectives. Specifically, we investigated how the relative importance of niche- and dispersal-based processes for community assembly change at two spatial scales: metacommunity scale, i.e. within a locality, and biogeographical scale, i.e. among localities widely scattered along a macroclimatic gradient. As expected, niche-based processes dominated the community assembly at metacommunity scale, while dispersal-based processes played a major role at biogeographical scale for both taxonomical groups. However, we also observed small but significant spatial effects at metacommunity scale and environmental effects at biogeographical scale. We also observed differences in diversity patterns between the two taxonomical groups corresponding to differences in their dispersal modes. Our results thus support the idea of continuity of processes interactively shaping diversity patterns across scales and emphasize the necessity of integration of metacommunity and biogeographical perspectives.

  12. Effects of natural phenomena and human activity on the species richness of endemic and non-endemic Heteroptera in the Canary Islands

    Directory of Open Access Journals (Sweden)

    Vargas, J. M.

    2004-12-01

    Full Text Available The geographical patterns of Heteroptera species diversity in the Canary Islands were analysed, and endemic and non–endemic species were studied both together and separately. Causal processes most likely controlling these patterns, as well as the theory of island biogeography, hypotheses about evolutionary time, habitat heterogeneity, climatic stability, intermediate disturbances, energy, environmental favourableness–severity, productivity and human influence were investigated. The combination of habitat heterogeneity and human influence accounted for the total number of species. However, when endemic and non–endemic species were analysed separately, habitat heterogeneity and favourableness–severity explained the richness of endemic species, whereas habitat heterogeneity and human influence explained that of non–endemic species.

  13. Revisiting Cementoblastoma with a Rare Case Presentation

    Directory of Open Access Journals (Sweden)

    Vijayanirmala Subramani

    2017-01-01

    Full Text Available Cementoblastoma is a rare benign odontogenic neoplasm which is characterized by the proliferation of cellular cementum. Diagnosis of cementoblastoma is challenging because of its protracted clinical, radiographic features, and bland histological appearance; most often cementoblastoma is often confused with other cementum and bone originated lesions. The aim of this article is to overview/revisit, approach the diagnosis of cementoblastoma, and also present a unique radiographic appearance of a cementoblastoma lesion associated with an impacted tooth.

  14. Vancouver Island gas supply

    International Nuclear Information System (INIS)

    Des Brisay, C.

    2005-01-01

    Terasen Gas is pursuing alternatives for the supply of additional natural gas capacity to Vancouver Island. Its subsidiary, Terasen Gas (Vancouver Island) Inc. (TGVI), is responding to the need for delivery of increased gas supply and, is supporting plans for new gas-fired power generation on Vancouver Island. TGVI's proposal for new natural gas capacity involves a combination of compression and pipeline loops as well as the addition of a storage facility for liquefied natural gas (LNG) at Mt. Hayes to help manage price volatility. This presentation outlined the objectives and components of the resource planning process, including demand forecast scenarios and the preferred infrastructure options. tabs., figs

  15. Madagascar sheds new light on the molecular systematics and biogeography of grammitid ferns: New unexpected lineages and numerous long-distance dispersal events.

    Science.gov (United States)

    Bauret, Lucie; Gaudeul, Myriam; Sundue, Michael A; Parris, Barbara S; Ranker, Tom A; Rakotondrainibe, France; Hennequin, Sabine; Ranaivo, Jaona; Selosse, Marc-André; Rouhan, Germinal

    2017-06-01

    Based on a worldwide phylogenetic framework filling the taxonomic gap of Madagascar and surrounding islands of the Western Indian Ocean (WIO), we revisited the systematics of grammitid fern species (Polypodiaceae). We also investigated the biogeographic origin of the extant diversity in Madagascar and estimated the relative influence of vicariance, long-distance dispersals (LDD) and in situ diversification. Phylogenetic inferences were based on five plastid DNA regions (atpB, rbcL, rps4-trnS, trnG-trnR, trnL-trnF) and the most comprehensive taxonomic sampling ever assembled (224 species belonging to 31 out of 33 recognized grammitids genera). 31 species from Madagascar were included representing 87% of the described diversity and 77% of the endemics. Our results confirmed a Paleotropical clade nested within an amphi-Atlantic grade. In addition, we identified three new major clades involving species currently belonging to Grammitis s.l., Ctenopterella and Enterosora. We resolved for the first time Grammitis s.s. as monophyletic, and Ctenopterella (newly tested here) and Enterosora as polyphyletic. The Neotropical genus Moranopteris was shown to also occur in Madagascar through a newly discovered species. Most importantly, we suggest a >30% inflation of the species number in the WIO due to the hidden diversity in >10 cryptic lineages, best explained by high morphological homoplasy. Molecular dating and ancestral areas reconstruction allowed identifying the Neotropics as the predominant source of LDD to the African-WIO region, with at least 12 colonization events within the last 20Ma. Repeated eastward migrations may be explained by transoceanic westerly winds transporting the dust-like spores. Tropical Asia s.l. would also have played a (minor) role through one dispersal event to Madagascar at the end of the Oligocene. Last, within the complex Malagasy region made of a mosaic of continental and oceanic islands located close to the African continent, we showed that

  16. Island formation without attractive interaction

    NARCIS (Netherlands)

    Jansen, A.P.J.

    2008-01-01

    We show that adsorbates on surfaces can form islands even if there are no attractive interactions. Instead, strong repulsion between adsorbates at short distances can lead to islands, because such islands increase the entropy of the adsorbates that are not part of the islands. We suggest that this

  17. Hacia una biogeografía evolutiva Towards an evolutionary biogeography

    Directory of Open Access Journals (Sweden)

    UANJ MORRONE

    2007-12-01

    Full Text Available La proliferación de métodos en las últimas décadas ha llevado a algunos autores a cuestionar si la biogeografía es una disciplina coherente. Las biotas son mosaicos complejos debidos a dispersión (expansión de las distribuciones y vicarianza (fragmentación de las distribuciones, teniendo historias complejas y reticuladas, que necesariamente deben estudiarse a través de la integración de diferentes metodologías. Un análisis biogeográfico evolutivo involucraría cinco etapas: (1 reconocimiento de componentes bióticos (conjuntos de taxa integrados espacio-temporalmente debido a una historia común, mediante la panbiogeografía y métodos para identificar áreas de endemismo; (2 contrastación de los componentes bióticos e identificación de los eventos vicariantes que los fragmentaron, mediante la biogeografía cladística y filogeografía comparada; (3 establecimiento de un arreglo jerárquico de los componentes en un sistema biogeográfico de reinos, regiones, dominios, provincias y distritos; (4 identificación de los cenocrones (conjuntos de taxa con edad y orígenes similares, datados mediante la filogeografía intraespecífica, relojes moleculares y fósiles; y (5 formulación de un escenario geobiótico, que explique la evolución de los componentes y cenocrones, integrando información geológica y tectónicaThe proliferation of methods in the last decades has led some authors to question whether biogeography is a coherent discipline. Biotas are complex mosaics due to dispersal (expansion of distributions and vicariance (fragmentation of distributions, having complex, reticulate histories, which necessarily need to be studied through the integration of different methodologies. An evolutionary biogeographical analysis may involve five steps: (1 recognition of biotic components (sets of spatio-temporally integrated taxa due to common history, through panbiogeography and methods used to identify areas of endemism; (2

  18. Global biogeography of scaly tree ferns (Cyatheaceae): evidence for Gondwanan vicariance and limited transoceanic dispersal.

    Science.gov (United States)

    Korall, Petra; Pryer, Kathleen M

    2014-02-01

    Scaly tree ferns, Cyatheaceae, are a well-supported group of mostly tree-forming ferns found throughout the tropics, the subtropics and the south-temperate zone. Fossil evidence shows that the lineage originated in the Late Jurassic period. We reconstructed large-scale historical biogeographical patterns of Cyatheaceae and tested the hypothesis that some of the observed distribution patterns are in fact compatible, in time and space, with a vicariance scenario related to the break-up of Gondwana. Tropics, subtropics and south-temperate areas of the world. The historical biogeography of Cyatheaceae was analysed in a maximum likelihood framework using Lagrange. The 78 ingroup taxa are representative of the geographical distribution of the entire family. The phylogenies that served as a basis for the analyses were obtained by Bayesian inference analyses of mainly previously published DNA sequence data using MrBayes. Lineage divergence dates were estimated in a Bayesian Markov chain Monte Carlo framework using beast. Cyatheaceae originated in the Late Jurassic in either South America or Australasia. Following a range expansion, the ancestral distribution of the marginate-scaled clade included both these areas, whereas Sphaeropteris is reconstructed as having its origin only in Australasia. Within the marginate-scaled clade, reconstructions of early divergences are hampered by the unresolved relationships among the Alsophila , Cyathea and Gymnosphaera lineages. Nevertheless, it is clear that the occurrence of the Cyathea and Sphaeropteris lineages in South America may be related to vicariance, whereas transoceanic dispersal needs to be inferred for the range shifts seen in Alsophila and Gymnosphaera . The evolutionary history of Cyatheaceae involves both Gondwanan vicariance scenarios as well as long-distance dispersal events. The number of transoceanic dispersals reconstructed for the family is rather few when compared with other fern lineages. We suggest that a causal

  19. Biogeography and molecular diversity of coral symbionts in the genus Symbiodinium around the Arabian Peninsula

    KAUST Repository

    Ziegler, Maren; Arif, Chatchanit; Burt, John A.; Dobretsov, Sergey; Roder, Cornelia; Lajeunesse, Todd C.; Voolstra, Christian R.

    2017-01-01

    Aim: Coral reefs rely on the symbiosis between scleractinian corals and intracellular, photosynthetic dinoflagellates of the genus Symbiodinium making the assessment of symbiont diversity critical to our understanding of ecological resilience of these ecosystems. This study characterizes Symbiodinium diversity around the Arabian Peninsula, which contains some of the most thermally diverse and understudied reefs on Earth. Location: Shallow water coral reefs throughout the Red Sea (RS), Sea of Oman (SO), and Persian/Arabian Gulf (PAG). Methods: Next-generation sequencing of the ITS2 marker gene was used to assess Symbiodinium community composition and diversity comprising 892 samples from 46 hard and soft coral genera. Results: Corals were associated with a large diversity of Symbiodinium, which usually consisted of one or two prevalent symbiont types and many types at low abundance. Symbiodinium communities were strongly structured according to geographical region and to a lesser extent by coral host identity. Overall symbiont communities were composed primarily of species from clade A and C in the RS, clade A, C, and D in the SO, and clade C and D in the PAG, representing a gradual shift from C- to D-dominated coral hosts. The analysis of symbiont diversity in an Operational Taxonomic Unit (OTU)-based framework allowed the identification of differences in symbiont taxon richness over geographical regions and host genera. Main conclusions: Our study represents a comprehensive overview over biogeography and molecular diversity of Symbiodinium in the Arabian Seas, where coral reefs thrive in one of the most extreme environmental settings on the planet. As such our data will serve as a baseline for further exploration into the effects of environmental change on host-symbiont pairings and the identification and ecological significance of Symbiodinium types from regions already experiencing 'Future Ocean' conditions.

  20. The developmental biogeography of hawksbill sea turtles in the North Pacific.

    Science.gov (United States)

    Van Houtan, Kyle S; Francke, Devon L; Alessi, Sarah; Jones, T Todd; Martin, Summer L; Kurpita, Lauren; King, Cheryl S; Baird, Robin W

    2016-04-01

    High seas oceanic ecosystems are considered important habitat for juvenile sea turtles, yet much remains cryptic about this important life-history period. Recent progress on climate and fishery impacts in these so-called lost years is promising, but the developmental biogeography of hawksbill sea turtles (Eretmochelys imbricata) has not been widely described in the Pacific Ocean. This knowledge gap limits the effectiveness of conservation management for this globally endangered species. We address this with 30 years of stranding observations, 20 years of bycatch records, and recent simulations of natal dispersal trajectories in the Hawaiian Archipelago. We synthesize the analyses of these data in the context of direct empirical observations, anecdotal sightings, and historical commercial harvests from the insular Pacific. We find hawksbills 0-4 years of age, measuring 8-34 cm straight carapace length, are found predominantly in the coastal pelagic waters of Hawaii. Unlike other species, we find no direct evidence of a prolonged presence in oceanic habitats, yet satellite tracks of passive drifters (simulating natal dispersal) and our small sample sizes suggest that an oceanic phase for hawksbills cannot be dismissed. Importantly, despite over 600 million hooks deployed and nearly 6000 turtle interactions, longline fisheries have never recorded a single hawksbill take. We address whether the patterns we observe are due to population size and gear selectivity. Although most sea turtle species demonstrate clear patterns of oceanic development, hawksbills in the North Pacific may by contrast occupy a variety of ecosystems including coastal pelagic waters and shallow reefs in remote atolls. This focuses attention on hazards in these ecosystems - entanglement and ingestion of marine debris - and perhaps away from longline bycatch and decadal climate regimes that affect sea turtle development in oceanic regions.

  1. Biogeography of pelagic bacterioplankton across an antagonistic temperature-salinity gradient in the Red Sea

    KAUST Repository

    Ngugi, David

    2011-12-01

    The Red Sea is a unique marine ecosystem with contrasting gradients of temperature and salinity along its north-to-south axis. It is an extremely oligotrophic environment that is characterized by perpetual year-round water column stratification, high annual solar irradiation, and negligible riverine and precipitation inputs. In this study, we investigated whether the contemporary environmental conditions shape community assemblages by pyrosequencing 16S rRNA genes of bacteria in surface water samples collected from the northeastern half of this water body. A combined total of 1855 operational taxonomic units (OTUs) were recovered from the \\'small-cell\\' and \\'large-cell\\' fractions. Here, a few major OTUs affiliated with Cyanobacteria and Proteobacteria accounted for â93% of all sequences, whereas a tail of \\'rare\\' OTUs represented most of the diversity. OTUs allied to Surface 1a/b SAR11 clades and Prochlorococcus related to the high-light-adapted (HL2) ecotype were the most widespread and predominant sequence types. Interestingly, the frequency of taxa that are typically found in the upper mesopelagic zone was significantly elevated in the northern transects compared with those in the central, presumably as a direct effect of deep convective mixing in the Gulf of Aqaba and water exchange with the northern Red Sea. Although temperature was the best predictor of species richness across all major lineages, both spatial and environmental distances correlated strongly with phylogenetic distances. Our results suggest that the bacterial diversity of the Red Sea is as high as in other tropical seas and provide evidence for fundamental differences in the biogeography of pelagic communities between the northern and central regions. © 2011 Blackwell Publishing Ltd.

  2. Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

    Directory of Open Access Journals (Sweden)

    Astrid Welk

    Full Text Available This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

  3. Biogeography of pelagic bacterioplankton across an antagonistic temperature-salinity gradient in the Red Sea

    KAUST Repository

    Ngugi, David; Antunes, Andre; Brune, Andreas; Stingl, Ulrich

    2011-01-01

    The Red Sea is a unique marine ecosystem with contrasting gradients of temperature and salinity along its north-to-south axis. It is an extremely oligotrophic environment that is characterized by perpetual year-round water column stratification, high annual solar irradiation, and negligible riverine and precipitation inputs. In this study, we investigated whether the contemporary environmental conditions shape community assemblages by pyrosequencing 16S rRNA genes of bacteria in surface water samples collected from the northeastern half of this water body. A combined total of 1855 operational taxonomic units (OTUs) were recovered from the 'small-cell' and 'large-cell' fractions. Here, a few major OTUs affiliated with Cyanobacteria and Proteobacteria accounted for â93% of all sequences, whereas a tail of 'rare' OTUs represented most of the diversity. OTUs allied to Surface 1a/b SAR11 clades and Prochlorococcus related to the high-light-adapted (HL2) ecotype were the most widespread and predominant sequence types. Interestingly, the frequency of taxa that are typically found in the upper mesopelagic zone was significantly elevated in the northern transects compared with those in the central, presumably as a direct effect of deep convective mixing in the Gulf of Aqaba and water exchange with the northern Red Sea. Although temperature was the best predictor of species richness across all major lineages, both spatial and environmental distances correlated strongly with phylogenetic distances. Our results suggest that the bacterial diversity of the Red Sea is as high as in other tropical seas and provide evidence for fundamental differences in the biogeography of pelagic communities between the northern and central regions. © 2011 Blackwell Publishing Ltd.

  4. Cosmopolitanism and Biogeography of the Genus Manganonema (Nematoda: Monhysterida in the Deep Sea

    Directory of Open Access Journals (Sweden)

    Roberto Danovaro

    2011-09-01

    Full Text Available Spatial patterns of species diversity provide information about the mechanisms that regulate biodiversity and are important for setting conservation priorities. Present knowledge of the biogeography of meiofauna in the deep sea is scarce. This investigation focuses on the distribution of the deep-sea nematode genus Manganonema, which is typically extremely rare in deep-sea sediment samples. Forty-four specimens of eight different species of this genus were recorded from different Atlantic and Mediterranean regions. Four out of the eight species encountered are new to science. We report here that this genus is widespread both in the Atlantic and in the Mediterranean Sea. These new findings together with literature information indicate that Manganonema is a cosmopolitan genus, inhabiting a variety of deep-sea habitats and oceans. Manganonema shows the highest diversity at water depths >4,000 m. Our data, therefore, indicate that this is preferentially an abyssal genus that is able, at the same time, to colonize specific habitats at depths shallower than 1,000 m. The analysis of the distribution of the genus Manganonema indicates the presence of large differences in dispersal strategies among different species, ranging from locally endemic to cosmopolitan. Lacking meroplanktonic larvae and having limited dispersal ability due to their small size, it has been hypothesized that nematodes have limited dispersal potential. However, the investigated deep-sea nematodes were present across different oceans covering macro-scale distances. Among the possible explanations (hydrological conditions, geographical and geological pathways, long-term processes, specific historical events, their apparent preference of colonizing highly hydrodynamic systems, could suggest that these infaunal organisms are transported by means of deep-sea benthic storms and turbidity currents over long distances.

  5. Elevational Distribution and Conservation Biogeography of Phanaeine Dung Beetles (Coleoptera: Scarabaeinae) in Bolivia

    Science.gov (United States)

    Herzog, Sebastian K.; Hamel-Leigue, A. Caroli; Larsen, Trond H.; Mann, Darren J.; Soria-Auza, Rodrigo W.; Gill, Bruce D.; Edmonds, W. D.; Spector, Sacha

    2013-01-01

    Insect macroecology and conservation biogeography studies are disproportionately scarce, especially in the Neotropics. Dung beetles are an ideal focal taxon for biodiversity research and conservation. Using distribution and body size data on the ecologically important Phanaeini, the best-known Neotropical dung beetle tribe, we determined elevational patterns of species richness, endemism, body size, and elevational range in Bolivia, specifically testing Bergmann’s and Rapoport’s rule. Richness of all 39 species and of 15 ecoregional endemics showed a hump-shaped pattern peaking at 400 m, but overall declined strongly with elevation up to 4000 m. The relationship between endemic and total species richness appeared to be curvilinear, providing only partial support for the null hypothesis that species-rich areas are more likely to be centers of endemism by chance alone. An elevational increase in the proportion of ecoregional endemics suggests that deterministic factors also appear to influence endemism in the Andes. When controlling for the effect of area using different species-area relationships, the statistically significant richness peak became more pronounced and shifted upslope to 750 m. Larger species did not have higher elevational mid-points, and mean body size decreased significantly with elevation, contradicting Bergmann’s rule. Rapoport’s rule was supported: species with higher elevational mid-points had broader elevational ranges, and mean elevational range increased significantly with elevation. The elevational decrease of phanaeine richness is in accordance with studies that demonstrated the combined influence of temperature and water availability on species diversity, but also is consistent with niche conservatism. For invertebrates, confirmation of Rapoport’s and refutation of Bergmann’s rule appear to be scale-invariant general patterns. Analyses of biogeographic patterns across elevational gradients can provide important insights for

  6. Species biogeography predicts drought responses in a seasonally dry tropical forest

    Science.gov (United States)

    Schwartz, N.; Powers, J. S.; Vargas, G.; Xu, X.; Smith, C. M.; Brodribb, T.; Werden, L. K.; Becknell, J.; Medvigy, D.

    2017-12-01

    The timing, distribution, and amount of rainfall in the seasonal tropics have shifted in recent years, with consequences for seasonally dry tropical forests (SDTF). SDTF are sensitive to changing rainfall regimes and drought conditions, but sensitivity to drought varies substantially across species. One potential explanation of species differences is that species that experience dry conditions more frequently throughout their range will be better able to cope with drought than species from wetter climates, because species from drier climates will be better adapted to drought. An El-Niño induced drought in 2015 presented an opportunity to assess species-level differences in mortality in SDTF, and to ask whether the ranges of rainfall conditions species experience and the average rainfall regimes in species' ranges predict differences in mortality rates in Costa Rican SDTF. We used field plot data from northwest Costa Rica to determine species' level mortality rates. Mortality rates ranged substantially across species, with some species having no dead individuals to as high as 50% mortality. To quantify rainfall conditions across species' ranges, we used species occurrence data from the Global Biodiversity Information Facility, and rainfall data from the Chelsa climate dataset. We found that while the average and range of mean annual rainfall across species ranges did not predict drought-induced mortality in the field plots, across-range averages of the seasonality index, a measure of rainfall seasonality, was strongly correlated with species-level drought mortality (r = -0.62, p < 0.05), with species from more strongly seasonal climates experiencing less severe drought mortality. Furthermore, we found that the seasonality index was a stronger predictor of mortality than any individual functional trait we considered. This result shows that species' biogeography may be an important factor for how species will respond to future drought, and may be a more integrative

  7. Biogeography and molecular diversity of coral symbionts in the genus Symbiodinium around the Arabian Peninsula

    KAUST Repository

    Ziegler, Maren

    2017-01-02

    Aim: Coral reefs rely on the symbiosis between scleractinian corals and intracellular, photosynthetic dinoflagellates of the genus Symbiodinium making the assessment of symbiont diversity critical to our understanding of ecological resilience of these ecosystems. This study characterizes Symbiodinium diversity around the Arabian Peninsula, which contains some of the most thermally diverse and understudied reefs on Earth. Location: Shallow water coral reefs throughout the Red Sea (RS), Sea of Oman (SO), and Persian/Arabian Gulf (PAG). Methods: Next-generation sequencing of the ITS2 marker gene was used to assess Symbiodinium community composition and diversity comprising 892 samples from 46 hard and soft coral genera. Results: Corals were associated with a large diversity of Symbiodinium, which usually consisted of one or two prevalent symbiont types and many types at low abundance. Symbiodinium communities were strongly structured according to geographical region and to a lesser extent by coral host identity. Overall symbiont communities were composed primarily of species from clade A and C in the RS, clade A, C, and D in the SO, and clade C and D in the PAG, representing a gradual shift from C- to D-dominated coral hosts. The analysis of symbiont diversity in an Operational Taxonomic Unit (OTU)-based framework allowed the identification of differences in symbiont taxon richness over geographical regions and host genera. Main conclusions: Our study represents a comprehensive overview over biogeography and molecular diversity of Symbiodinium in the Arabian Seas, where coral reefs thrive in one of the most extreme environmental settings on the planet. As such our data will serve as a baseline for further exploration into the effects of environmental change on host-symbiont pairings and the identification and ecological significance of Symbiodinium types from regions already experiencing \\'Future Ocean\\' conditions.

  8. Pole-to-pole biogeography of surface and deep marine bacterial communities

    Science.gov (United States)

    Ghiglione, Jean-François; Galand, Pierre E.; Pommier, Thomas; Pedrós-Alió, Carlos; Maas, Elizabeth W.; Bakker, Kevin; Bertilson, Stefan; Kirchman, David L.; Lovejoy, Connie; Yager, Patricia L.; Murray, Alison E.

    2012-01-01

    The Antarctic and Arctic regions offer a unique opportunity to test factors shaping biogeography of marine microbial communities because these regions are geographically far apart, yet share similar selection pressures. Here, we report a comprehensive comparison of bacterioplankton diversity between polar oceans, using standardized methods for pyrosequencing the V6 region of the small subunit ribosomal (SSU) rRNA gene. Bacterial communities from lower latitude oceans were included, providing a global perspective. A clear difference between Southern and Arctic Ocean surface communities was evident, with 78% of operational taxonomic units (OTUs) unique to the Southern Ocean and 70% unique to the Arctic Ocean. Although polar ocean bacterial communities were more similar to each other than to lower latitude pelagic communities, analyses of depths, seasons, and coastal vs. open waters, the Southern and Arctic Ocean bacterioplankton communities consistently clustered separately from each other. Coastal surface Southern and Arctic Ocean communities were more dissimilar from their respective open ocean communities. In contrast, deep ocean communities differed less between poles and lower latitude deep waters and displayed different diversity patterns compared with the surface. In addition, estimated diversity (Chao1) for surface and deep communities did not correlate significantly with latitude or temperature. Our results suggest differences in environmental conditions at the poles and different selection mechanisms controlling surface and deep ocean community structure and diversity. Surface bacterioplankton may be subjected to more short-term, variable conditions, whereas deep communities appear to be structured by longer water-mass residence time and connectivity through ocean circulation. PMID:23045668

  9. Macroevolutionary dynamics and historical biogeography of primate diversification inferred from a species supermatrix.

    Directory of Open Access Journals (Sweden)

    Mark S Springer

    Full Text Available Phylogenetic relationships, divergence times, and patterns of biogeographic descent among primate species are both complex and contentious. Here, we generate a robust molecular phylogeny for 70 primate genera and 367 primate species based on a concatenation of 69 nuclear gene segments and ten mitochondrial gene sequences, most of which were extracted from GenBank. Relaxed clock analyses of divergence times with 14 fossil-calibrated nodes suggest that living Primates last shared a common ancestor 71-63 Ma, and that divergences within both Strepsirrhini and Haplorhini are entirely post-Cretaceous. These results are consistent with the hypothesis that the Cretaceous-Paleogene mass extinction of non-avian dinosaurs played an important role in the diversification of placental mammals. Previous queries into primate historical biogeography have suggested Africa, Asia, Europe, or North America as the ancestral area of crown primates, but were based on methods that were coopted from phylogeny reconstruction. By contrast, we analyzed our molecular phylogeny with two methods that were developed explicitly for ancestral area reconstruction, and find support for the hypothesis that the most recent common ancestor of living Primates resided in Asia. Analyses of primate macroevolutionary dynamics provide support for a diversification rate increase in the late Miocene, possibly in response to elevated global mean temperatures, and are consistent with the fossil record. By contrast, diversification analyses failed to detect evidence for rate-shift changes near the Eocene-Oligocene boundary even though the fossil record provides clear evidence for a major turnover event ("Grande Coupure" at this time. Our results highlight the power and limitations of inferring diversification dynamics from molecular phylogenies, as well as the sensitivity of diversification analyses to different species concepts.

  10. Phylogeny of the non-monophyletic Cayratia Juss. (Vitaceae) and implications for character evolution and biogeography.

    Science.gov (United States)

    Lu, Limin; Wang, Wei; Chen, Zhiduan; Wen, Jun

    2013-09-01

    Cayratia consists of ca. 60 species primarily distributed in the tropical and subtropical regions of Asia, Australia, and Africa. It is an excellent candidate for exploring the evolution of intercontinental disjunct distributions in the Old World. Previous phylogenetic work of Vitaceae with a few species of Cayratia sampled showed that Cayratia was not monophyletic and was closely related to Cyphostemma and Tetrastigma. We herein expanded taxon sampling of Cayratia (25/60 species) with its allied genera Cyphostemma (39/150 species), Tetrastigma (27/95 species), and other related genera from Vitaceae represented, employing five plastid markers (atpB-rbcL, rps16, trnC-petN, trnH-psbA, and trnL-F), to investigate the phylogeny, character evolution and biogeography of Cayratia. The phylogenetic analyses have confirmed the monophyly of the Cayratia-Cyphostemma-Tetrastigma (CCT) clade and resolved Cayratia into three lineages: the African Cayratia clade, subg. Cayratia, and subg. Discypharia. The African Cayratia was supported as the first diverging lineage within the CCT clade and Tetrastigma is resolved as sister to subg. Discypharia. Character optimizations suggest that the presence/absence of a membrane enclosing the ventral infolds in seeds is an important character for the taxonomy of Cayratia. The presence of bracts on the lower part of the inflorescence axis is inferred to have arisen only once in Cayratia, but this character evolved several times in Tetrastigma. Both the branching pattern of tendrils and the leaf architecture are suggested as important infrageneric characters, but should be used cautiously because some states evolved multiple times. Ancestral area reconstruction and molecular dating suggest that the CCT clade originated from continental Africa in the late Cretaceous, and it then reached Asia twice independently in the late Cretaceous and late Oligocene, respectively. Several dispersals are inferred from Asia to Australia since the Eocene

  11. Coalescence of magnetic islands

    International Nuclear Information System (INIS)

    Pellat, R.

    1982-01-01

    The paper gives the analytical theory of the coalescence instability and of a new, one island, instability. These instabilities are expected to be relevant for the disruptions observed in Tokamak experiments and astrophysical plasmas

  12. Heat Island Compendium

    Science.gov (United States)

    Heat islands can be mitigated through measures like planting trees and vegetation, installing green roofs and cool roofs, and using cool pavements. The compendium describes all of these strategies and shows how communities around the country are being used

  13. Islands and Islandness in Rock Music Lyrics

    Directory of Open Access Journals (Sweden)

    Daniele Mezzana

    2012-05-01

    Full Text Available This paper presents a first exploration, qualitative in character, based on a review of 412 songs produced in the period 1960-2009, about islands in rock music as both social products and social tools potentially contributing to shaping ideas, emotions, will, and desires. An initial taxonomy of 24 themes clustered under five meta-themes of space, lifestyle, emotions, symbolism, and social-political relations is provided, together with some proposals for further research.

  14. Diversity and composition of the copepod communities associated with megafauna around a cold seep in the Gulf of Mexico with remarks on species biogeography

    NARCIS (Netherlands)

    Plum, C.; Gollner, S.; Martinez Arbizu, P.; Bright, M.

    2015-01-01

    In order to characterize the copepod communitiesassociated with tubeworm and mussel aggregations around ahydrocarbon seep in the Green Canyon of the Gulf of Mexico,diversity, abundance, and community composition were analyzed.Also analyzed were species biogeography and the potentialconnectivity to

  15. Delving into Delias Hübner (Lepidoptera: Pireridae): fine-scale biogeography, phylogenetics and systematics of the world’s largest butterfly genus

    Czech Academy of Sciences Publication Activity Database

    Müller, C. J.; Matos Maravi, Pavel F.; Beheregaray, L. B.

    2013-01-01

    Roč. 40, č. 5 (2013), s. 881-893 ISSN 0305-0270 Institutional support: RVO:60077344 Keywords : butterflies * DEC model * historical biogeography Subject RIV: EG - Zoology Impact factor: 4.969, year: 2013 http://onlinelibrary.wiley.com/doi/10.1111/jbi.12040/pdf

  16. Biogeography of Aegagropila linnaei (Cladophorophyceae, Chlorophyta): a widespread freshwater alga with low effective dispersal potential shows a glacial imprint in its distribution

    NARCIS (Netherlands)

    Boedeker, C.; Eggert, A.; Immers, A.; Wakana, I.

    2010-01-01

    Aim:Aegagropila linnaei is a freshwater macroalga that is generally regarded as a rare species. It is apparently absent from large but seemingly suitable areas of the Northern Hemisphere, implying a limited dispersal potential and an imprint of Pleistocene glaciations in its biogeography. However,

  17. The World Bacterial Biogeography and Biodiversity through Databases: A Case Study of NCBI Nucleotide Database and GBIF Database

    Directory of Open Access Journals (Sweden)

    Okba Selama

    2013-01-01

    Full Text Available Databases are an essential tool and resource within the field of bioinformatics. The primary aim of this study was to generate an overview of global bacterial biodiversity and biogeography using available data from the two largest public online databases, NCBI Nucleotide and GBIF. The secondary aim was to highlight the contribution each geographic area has to each database. The basis for data analysis of this study was the metadata provided by both databases, mainly, the taxonomy and the geographical area origin of isolation of the microorganism (record. These were directly obtained from GBIF through the online interface, while E-utilities and Python were used in combination with a programmatic web service access to obtain data from the NCBI Nucleotide Database. Results indicate that the American continent, and more specifically the USA, is the top contributor, while Africa and Antarctica are less well represented. This highlights the imbalance of exploration within these areas rather than any reduction in biodiversity. This study describes a novel approach to generating global scale patterns of bacterial biodiversity and biogeography and indicates that the Proteobacteria are the most abundant and widely distributed phylum within both databases.

  18. Morphological variation, biogeography and local extinction of the northern New Zealand landsnail Placostylus hongii (Gastropoda : Bulimulidae)

    International Nuclear Information System (INIS)

    Brook, F.J.; McArdle, B.H.

    1999-01-01

    Placostylus hongii (Lesson) is recorded from sites between Whangaroa and Whangarei on the mainland Northland coast, and from the Poor Knights, Chicken, Mokohinau and Great Barrier islands offshore. There is considerable variation in shell morphology between the various populations, commonly with marked morphological divergence at a local scale but with overlapping variation overall across all populations of the taxon. Patterns of morphological variation show no clear geographic trends and are at least in part related to local environmental factors. Correlations are identified between shell shape and substratum type, and between shell size and vegetation type. Placostylus hongii has a very restricted stratigraphic distribution in mainland Northland, with most if not all of the few known fossil populations post-dating Polynesian settlement at c. 900-700 years BP. We suggest that P. hongii populations on the Poor Knights and possibly also those on the Mokohinau islands are endemic, whereas the mainland populations and those on Great Barier and the Chicken islands have originated from anthropic redistribution of snails in prehistoric time. A high proportion of the mainland P. hongii populations and some offshore island populations became extinct in the last few hundred years as a result of predation by introduced mammals and the modification and destruction of shrubland and forest habitat. (author). 54 refs., 9 figs., 1 tab

  19. Advanced Change Theory Revisited: An Article Critique

    Directory of Open Access Journals (Sweden)

    R. Scott Pochron

    2008-12-01

    Full Text Available The complexity of life in 21st century society requires new models for leading and managing change. With that in mind, this paper revisits the model for Advanced Change Theory (ACT as presented by Quinn, Spreitzer, and Brown in their article, “Changing Others Through Changing Ourselves: The Transformation of Human Systems” (2000. The authors present ACT as a potential model for facilitating change in complex organizations. This paper presents a critique of the article and summarizes opportunities for further exploring the model in the light of current trends in developmental and integral theory.

  20. Resolution of Reflection Seismic Data Revisited

    DEFF Research Database (Denmark)

    Hansen, Thomas Mejer; Mosegaard, Klaus; Zunino, Andrea

    The Rayleigh Principle states that the minimum separation between two reflectors that allows them to be visually separated is the separation where the wavelet maxima from the two superimposed reflections combine into one maximum. This happens around Δtres = λb/8, where λb is the predominant...... lower vertical resolution of reflection seismic data. In the following we will revisit think layer model and demonstrate that there is in practice no limit to the vertical resolution using the parameterization of Widess (1973), and that the vertical resolution is limited by the noise in the data...

  1. Revisiting fifth forces in the Galileon model

    Energy Technology Data Exchange (ETDEWEB)

    Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie; Seery, David [Sussex Univ., Brighton (United Kingdom). Dept. of Physics and Astronomy

    2010-05-15

    A Galileon field is one which obeys a spacetime generalization of the non- relativistic Galilean invariance. Such a field may possess non-canonical kinetic terms, but ghost-free theories with a well-defined Cauchy problem exist, constructed using a finite number of relevant operators. The interactions of this scalar with matter are hidden by the Vainshtein effect, causing the Galileon to become weakly coupled near heavy sources. We revisit estimates of the fifth force mediated by a Galileon field, and show that the parameters of the model are less constrained by experiment than previously supposed. (orig.)

  2. Large J expansion in ABJM theory revisited.

    Science.gov (United States)

    Dimov, H; Mladenov, S; Rashkov, R C

    Recently there has been progress in the computation of the anomalous dimensions of gauge theory operators at strong coupling by making use of the AdS/CFT correspondence. On the string theory side they are given by dispersion relations in the semiclassical regime. We revisit the problem of a large-charge expansion of the dispersion relations for simple semiclassical strings in an [Formula: see text] background. We present the calculation of the corresponding anomalous dimensions of the gauge theory operators to an arbitrary order using three different methods. Although the results of the three methods look different, power series expansions show their consistency.

  3. Sloan Digital Sky Survey Photometric Calibration Revisited

    International Nuclear Information System (INIS)

    Marriner, John

    2012-01-01

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  4. Revisiting the Political Economy of Communication

    Directory of Open Access Journals (Sweden)

    Nicholas Garnham

    2014-02-01

    The task of the paper and the seminar was to revisit some of Nicholas Garnham’s ideas, writings and contributions to the study of the Political Economy of Communication and to reflect on the concepts, history, current status and perspectives of this field and the broader study of political economy today. The topics covered include Raymond Williams’ cultural materialism, Pierre Bourdieu’s sociology of culture, the debate between Political Economy and Cultural Studies, information society theory, Karl Marx’s theory and the critique of capitalism.

  5. Sloan Digital Sky Survey Photometric Calibration Revisited

    Energy Technology Data Exchange (ETDEWEB)

    Marriner, John; /Fermilab

    2012-06-29

    The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.

  6. Heron Island, Australia

    Science.gov (United States)

    2002-01-01

    Heron Island is located at the sourthern end of Australia's 2,050 km-long Great Barrier Reef. Surrounded by coral reef and home to over 1000 species of fish, scuba divers and scientists alike are drawn to the island's resort and research station. The true-color image above was taken by Space Imaging's Ikonos satellite with a resolution of 4 meters per pixel-high enough to see individual boats tied up at the small marina. The narrow channel leading from the marina to the ocean was blasted and dredged decades ago, before the island became a national park. Since then the Australian government has implemented conservation measures, such as limiting the number of tourists and removing or recycling, instead of incinerating, all trash. One of the applications of remote sensing data from Ikonos is environmental monitoring, including studies of coral reef health. For more information about the island, read Heron Island. Image by Robert Simmon, based on data copyright Space Imaging

  7. Biogeography and potential exchanges among the atlantic Equatorial belt cold-seep faunas.

    Directory of Open Access Journals (Sweden)

    Karine Olu

    2010-08-01

    Full Text Available Like hydrothermal vents along oceanic ridges, cold seeps are patchy and isolated ecosystems along continental margins, extending from bathyal to abyssal depths. The Atlantic Equatorial Belt (AEB, from the Gulf of Mexico to the Gulf of Guinea, was one focus of the Census of Marine Life ChEss (Chemosynthetic Ecosystems program to study biogeography of seep and vent fauna. We present a review and analysis of collections from five seep regions along the AEB: the Gulf of Mexico where extensive faunal sampling has been conducted from 400 to 3300 m, the Barbados accretionary prism, the Blake ridge diapir, and in the Eastern Atlantic from the Congo and Gabon margins and the recently explored Nigeria margin. Of the 72 taxa identified at the species level, a total of 9 species or species complexes are identified as amphi-Atlantic. Similarity analyses based on both Bray Curtis and Hellinger distances among 9 faunal collections, and principal component analysis based on presence/absence of megafauna species at these sites, suggest that within the AEB seep megafauna community structure is influenced primarily by depth rather than by geographic distance. Depth segregation is observed between 1000 and 2000 m, with the middle slope sites either grouped with those deeper than 2000 m or with the shallower sites. The highest level of community similarity was found between the seeps of the Florida escarpment and Congo margin. In the western Atlantic, the highest degree of similarity is observed between the shallowest sites of the Barbados prism and of the Louisiana slope. The high number of amphi-atlantic cold-seep species that do not cluster according to biogeographic regions, and the importance of depth in structuring AEB cold-seep communities are the major conclusions of this study. The hydrothermal vent sites along the Mid Atlantic Ridge (MAR did not appear as "stepping stones" for dispersal of the AEB seep fauna, however, the south MAR and off axis regions

  8. The bee tree of life: a supermatrix approach to apoid phylogeny and biogeography.

    Science.gov (United States)

    Hedtke, Shannon M; Patiny, Sébastien; Danforth, Bryan N

    2013-07-03

    Bees are the primary pollinators of angiosperms throughout the world. There are more than 16,000 described species, with broad variation in life history traits such as nesting habitat, diet, and social behavior. Despite their importance as pollinators, the evolution of bee biodiversity is understudied: relationships among the seven families of bees remain controversial, and no empirical global-level reconstruction of historical biogeography has been attempted. Morphological studies have generally suggested that the phylogeny of bees is rooted near the family Colletidae, whereas many molecular studies have suggested a root node near (or within) Melittidae. Previous molecular studies have focused on a relatively small sample of taxa (~150 species) and genes (seven at most). Public databases contain an enormous amount of DNA sequence data that has not been comprehensively analysed in the context of bee evolution. We downloaded, aligned, concatenated, and analysed all available protein-coding nuclear gene DNA sequence data in GenBank as of October, 2011. Our matrix consists of 20 genes, with over 17,000 aligned nucleotide sites, for over 1,300 bee and apoid wasp species, representing over two-thirds of bee genera. Whereas the matrix is large in terms of number of genes and taxa, there is a significant amount of missing data: only ~15% of the matrix is populated with data. The placement of the root as well as relationships between Andrenidae and other bee families remain ambiguous, as several alternative maximum-likelihood estimates fall within the statistically credible set. However, we recover strong bootstrap support for relationships among many families and for their monophyly. Ancestral geographic range reconstruction suggests a likely origin of bees in the southern hemisphere, with Melittidae ancestrally located within Africa, and Halictidae, Colletidae, and Apidae within the New World. Our study affirms the monophyly of each bee family, sister-taxa relationships

  9. Small Island Visitor Attractions

    Directory of Open Access Journals (Sweden)

    Haven Allahar

    2015-03-01

    Full Text Available This article proposes a process framework for developing and managing visitor attractions (VA in small island developing states with Trinidad and Tobago, a two-island state in the Caribbean, as the case study. An extensive literature review was conducted, supported by field observations, individual depth interviews, and small and large focus group meetings. The process framework identified four sets of processes: national policy formulation and legislation; inventory, classification, evaluation, and ranking of VA; general operations management involving project management activities; and site specific activities of development, operations, and maintenance. The value of the framework lies in the fact that no similar framework applicable to small islands was covered in the literature and validation was obtained from a panel of experts and a cross section of tourism stakeholders in Tobago.

  10. Benefits, barriers, and intentions/desires of nurses related to distance learning in rural island communities.

    Science.gov (United States)

    Kataoka-Yahiro, Merle R; Richardson, Karol; Mobley, Joseph

    2011-03-01

    This study assessed distance learning needs among nurses on the Neighbor Islands in Hawaii. An exploratory study was conducted using a descriptive qualitative design. Of the 37 nurses who completed the study, 7 were nurse administrators and 30 were staff nurses. There were 18 focus groups of nurses recruited from six public hospitals on the Neighbor Islands. Three major themes related to distance learning emerged in this study: benefits, barriers, and intentions/desires. Each major theme had several linkages to categories and subcategories. Overall findings were as follows: (1) cost was mentioned more often in three major thematic areas (benefit, barriers, and intentions/desires); (2) the need to revisit and address current curriculum approaches and practices in distance learning programs was identified; and (3) strong recommendations were made for programs and organizational support for distance learning in hospital settings. These findings have implications for nursing research, education, and practice. Copyright 2011, SLACK Incorporated.

  11. Island of Luzon, Philippines

    Science.gov (United States)

    1990-01-01

    In this north to south view of the Island of Luzon, Philippines (13.0N, 120.0E), the prominent Cordillera Central mountain range where gold, copper and silver are mined. The several large rivers that drain this region normally carry a heavy silt load to the sea but the absence of sediment plumes in this view is evidence of hot dry weather and lack of recent rains. Manila, the capital city is just visible at the south end of the island.

  12. Chatham Islands Climate Change

    International Nuclear Information System (INIS)

    Mullan, B.; Salinger, J.; Thompson, C.; Ramsay, D.; Wild, M.

    2005-06-01

    This brief report provides guidance on climate change specific to the Chatham Islands, to complement the information recently produced for local government by the Ministry for the Environment in 'Climate Change Effects and Impacts Assessment: A guidance manual for Local Government in New Zealand' and 'Coastal Hazards and Climate Change: A guidance manual for Local Government in New Zealand'. These previous reports contain a lot of generic information on climate change, and how to assess associated risks, that is relevant to the Chatham Islands Council.

  13. Island in the Air

    DEFF Research Database (Denmark)

    Simonsen, Dorthe Gert

    2017-01-01

    In this article, I explore the formation of airspace in Britain from 1910 to 1913. The technology of flight challenged the “flat discourse” of nationalized geography, drawing up instead a volumetric space in the sky as airplanes flew from the Continent to England. The drive to control aerial...... extension of the Island Kingdom, extrapolating its coastal borders into the sky. However, even as Parliament passed the Aerial Navigation Act in 1913, this legal construction of an island in the air could not endure the agency of airplanes. The formation of airspace, I argue, is a history particularly well...

  14. Archaeoastronomy of Easter Island

    Science.gov (United States)

    Edwards, Edmundo

    Astronomer priests or "skywatchers" on Easter Island lived in stone towers that were used as observatories and built stone markers in the periphery that indicated the heliacal rising of certain stars that served to indicate the arrival of marine birds, turtles, the offshore fishing season, and times for planting and harvest. Petroglyphs related to such sites depict outriggers, fishhooks, pelagic fish, and turtles and supposedly represented a star map. In this chapter, we analyze a set of such skywatchers dwellings, and stone markers located upon the North coast of Easter Island that have astronomic orientations, its related petroglyphs, and the relations between these directions with their yearly activities and their ritual calendar.

  15. Long Island Solar Farm

    Energy Technology Data Exchange (ETDEWEB)

    Anders, R.

    2013-05-01

    The Long Island Solar Farm (LISF) is a remarkable success story, whereby very different interest groups found a way to capitalize on unusual circumstances to develop a mutually beneficial source of renewable energy. The uniqueness of the circumstances that were necessary to develop the Long Island Solar Farm make it very difficult to replicate. The project is, however, an unparalleled resource for solar energy research, which will greatly inform large-scale PV solar development in the East. Lastly, the LISF is a superb model for the process by which the project developed and the innovation and leadership shown by the different players.

  16. Taxonomic status and paleoecology of Rusingoryx atopocranion (Mammalia, Artiodactyla), an extinct Pleistocene bovid from Rusinga Island, Kenya

    Science.gov (United States)

    Faith, J. Tyler; Choiniere, Jonah N.; Tryon, Christian A.; Peppe, Daniel J.; Fox, David L.

    2011-05-01

    Rusingoryx atopocranion is a poorly known extinct alcelaphine bovid, documented in Pleistocene deposits associated with Middle Stone Age artifacts on Rusinga Island, Kenya. Following its initial description, Rusingoryx was subsumed into Megalotragus, which includes the extinct giant wildebeests, on the basis of its cranial architecture. Renewed investigations of the Pleistocene deposits on Rusinga Island recovered a large sample of Rusingoryx specimens that provide new taxonomic and paleoecological insight. This study (1) reviews the morphological and phylogenetic evidence concerning the taxonomic status of Rusingoryx and (2) evaluates its paleoecology and dietary habits . The morphology and phylogenetic data indicate that Rusingoryx is distinct from Megalotragus; they likely shared a common ancestor in the late Pliocene. Ecomorphology and mesowear analysis point to a specialized grazing adaptation, and its association with arid-adapted ungulates suggests a preference for arid grasslands. The confirmation of Rusingoryx as a valid taxonomic entity, together with the presence of other extinct taxa (including Megalotragus) on Rusinga Island, suggests an increasingly complex pattern of ungulate biogeography and extinctions in the late Quaternary of East Africa. Rusingoryx appears to have been part of an arid-adapted faunal community that potentially persisted in East Africa until the onset of the Holocene.

  17. Islanded operation of distribution networks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the results of a study assessing the benefits and risks to distribution network of generator islanding and examining the technical, commercial and regulatory changes required to facilitate the operation of islanding. The background to the study is traced, and details are given of a literature review, the technical criteria for operating sections of the network in islanding mode, and the impact of islanding on trading. Case studies and a detailed implementation plan, data acquisition, and commercial incentives are discussed.

  18. Islanded operation of distribution networks

    International Nuclear Information System (INIS)

    2005-01-01

    This report summarises the results of a study assessing the benefits and risks to distribution network of generator islanding and examining the technical, commercial and regulatory changes required to facilitate the operation of islanding. The background to the study is traced, and details are given of a literature review, the technical criteria for operating sections of the network in islanding mode, and the impact of islanding on trading. Case studies and a detailed implementation plan, data acquisition, and commercial incentives are discussed

  19. Pediatrics in the Marshall Islands

    International Nuclear Information System (INIS)

    Dungy, C.I.; Morgan, B.C.; Adams, W.H.

    1984-01-01

    The delivery of health care to children living on isolated island communities presents unique challenges to health professionals. An evolved method of providing longitudinal services to infants and children residing on islands of the Marshall Island chain - a central Pacific portion of the Micronesian archipelago - is presented. The difficulties associated with provision of comprehensive health care in a vast ocean area are discussed

  20. The Island Smart Energy System and Market

    DEFF Research Database (Denmark)

    Ma, Zheng; Billanes, Joy Dalmacio; Jørgensen, Bo Nørregaard

    2017-01-01

    developing island smart energy systems with the integration of renewable energy resources can increase the energy supply and address the global island energy issues. The island smart energy system operates either in a single-island or in multi-islands. However the island characteristics and influ...

  1. Solomon Islands Botany

    NARCIS (Netherlands)

    Steenis, van C.G.G.J.

    1969-01-01

    A discussion of the Results of the Royal Society Expedition to the British Solomon Islands Protectorate, 1965. Organized by E.J.H. Corner. Phil. Trans. R. Soc. B 255 (1969) 185-631, 196 fig. University Printing House, Shaftesbury Road, Cambridge. Obtainable through booksellers or direct to the Royal

  2. Pacific Island Pharmacovigilance

    DEFF Research Database (Denmark)

    McEwen, John; Vestergaard, Lasse S.; Sanburg, Amanda L C

    2016-01-01

    Many Pacific Island countries (PICs) are recipients of funding support from the Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund). However, most of these countries cannot be expected to meet Global Fund and World Health Organization (WHO) minimum requirements for a functioning...

  3. Magnetic-island formation

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1983-08-01

    The response of a finite conductivity plasma to resonant magnetic perturbations is studied. The equations, which are derived for the time development of magnetic islands, help one interpret the singular currents which occur under the assumption of perfect plasma conductivity. The relation to the Rutherford regime of resistive instabilities is given

  4. Bone island and leprosy

    Energy Technology Data Exchange (ETDEWEB)

    Carpintero, P.; Garcia-Frasquet, A. [Department of Orthopaedic Surgery, Cordoba University, Medical School, Reina Sofia University Hospital, Cordoba (Spain); Tarradas, E. [Department of Imaging, Cordoba University, Medical School, Cordoba (Spain); Logrono, C. [Department of Dermatology, Reina Sofia University Hospital, Cordoba (Spain); Carrascal, A. [Department of Radiology, Infanta Elena Hospital, Huelva (Spain); Carreto, A. [Department of Radiology, Reina Sofia University Hospital, Cordoba (Spain)

    1998-06-01

    Objective. To determine the incidence of bone islands in leprosy patients. Design. X-rays of feet and hands of patients with Hansen`s disease (leprosy) were reviewed retrospectively. A second group of related age- and sex-matched patients who did not have Hansen`s disease was used for control purposes. Controls had undergone hand or foot X-rays during diagnosis of other pathologies. The patients with Hansen`s disease were compared with the control group, and were also analyzed as subgroups with different types of leprosy. The results were subjected to statistical analysis. Patients. Ninety patients with Hansen`s disease were randomly selected for this study. Patients who had had ulcers on hands or feet were excluded from the study. Results and conclusions. Bone islands were demonstrated in 20 patients with Hansen`s disease; no bone islands were observed in the controls. This was statistically significant (P<0.01). Bone islands were only seen in patients with lepromatous leprosy and borderline types but were not demonstrated in patients with tuberculoid leprosy. There was also a statistically significant relationship for a disease duration of 15 years or more. The cause of this raised incidence of enostosis in leprosy patients is not clear, but there may be a genetic predisposition in patients with leprosy, or it may be a side effect of leprosy, especially the lepromatous form. (orig.) With 4 figs., 2 tabs., 9 refs.

  5. Bone island and leprosy

    International Nuclear Information System (INIS)

    Carpintero, P.; Garcia-Frasquet, A.; Tarradas, E.; Logrono, C.; Carrascal, A.; Carreto, A.

    1998-01-01

    Objective. To determine the incidence of bone islands in leprosy patients. Design. X-rays of feet and hands of patients with Hansen's disease (leprosy) were reviewed retrospectively. A second group of related age- and sex-matched patients who did not have Hansen's disease was used for control purposes. Controls had undergone hand or foot X-rays during diagnosis of other pathologies. The patients with Hansen's disease were compared with the control group, and were also analyzed as subgroups with different types of leprosy. The results were subjected to statistical analysis. Patients. Ninety patients with Hansen's disease were randomly selected for this study. Patients who had had ulcers on hands or feet were excluded from the study. Results and conclusions. Bone islands were demonstrated in 20 patients with Hansen's disease; no bone islands were observed in the controls. This was statistically significant (P<0.01). Bone islands were only seen in patients with lepromatous leprosy and borderline types but were not demonstrated in patients with tuberculoid leprosy. There was also a statistically significant relationship for a disease duration of 15 years or more. The cause of this raised incidence of enostosis in leprosy patients is not clear, but there may be a genetic predisposition in patients with leprosy, or it may be a side effect of leprosy, especially the lepromatous form. (orig.)

  6. Molecular phylogenetic analysis of Commiphora (Burseraceae) yields insight on the evolution and historical biogeography of an "impossible" genus.

    Science.gov (United States)

    Weeks, Andrea; Simpson, Beryl B

    2007-01-01

    Expansion of the arid zone of sub-Saharan tropical Africa during the Miocene is posited as a significant contributing factor in the evolution of contemporary African flora. Nevertheless, few molecular phylogenetic studies have tested this hypothesis using reconstructed historical biogeographies of plants within this zone. Here, we present a molecular phylogeny of Commiphora, a predominantly tropical African, arid-adapted tree genus, in order to test the monophyly of its taxonomic sections and identify clades that will help direct future study of this species-rich and geographically widespread taxon. We then use multiple fossil calibrations of Commiphora phylogeny to determine the timing of well-supported diversification events within the genus and interpret these age estimates to determine the relative contribution of vicariance and dispersal in the expansion of Commiphora's geographic range. We find that Commiphora is sister to Vietnamese Bursera tonkinensis and that its crown group radiation corresponds with the onset of the Miocene.

  7. Multidecadal shoreline changes of atoll islands in the Marshall Islands

    Science.gov (United States)

    Ford, M.

    2012-12-01

    Atoll islands are considered highly vulnerable to the impacts of continued sea level rise. One of the most commonly predicted outcomes of continued sea level rise is widespread and chronic shoreline erosion. Despite the widespread implications of predicted erosion, the decadal scale changes of atoll island shorelines are poorly resolved. The Marshall Islands is one of only four countries where the majority of inhabited land is comprised of reef and atoll islands. Consisting of 29 atolls and 5 mid-ocean reef islands, the Marshall Islands are considered highly vulnerable to the impacts of sea level rise. A detailed analysis of shoreline change on over 300 islands on 10 atolls was undertaken using historic aerial photos (1945-1978) and modern high resolution satellite imagery (2004-2012). Results highlight the complex and dynamic nature of atoll islands, with significant shifts in shoreline position observed over the period of analysis. Results suggest shoreline accretion is the dominant mode of change on the islands studied, often associated with a net increase in vegetated island area. However, considerable inter- and intra-atoll variability exists with regards to shoreline stability. Findings are discussed with respect to island morphodynamics and potential hazard mitigation and planning responses within atoll settings.

  8. Polyphyletic migration operator and orthogonal learning aided biogeography-based optimization for dynamic economic dispatch with valve-point effects

    International Nuclear Information System (INIS)

    Xiong, Guojiang; Li, Yinhong; Chen, Jinfu; Shi, Dongyuan; Duan, Xianzhong

    2014-01-01

    Highlights: • New method for dynamic economic dispatch problem using POLBBO. • Considering valve-point effects, ramp rate limits, transmission network losses. • POLBBO is able to balance the global exploration and the local exploitation. • An effective simultaneous constraints handling technique is proposed. • The achieved results by POLBBO are better than those reported in other literatures. - Abstract: Shortage of energy resources, rising power generation cost, and increasing electric energy demand make the dynamic economic dispatch (DED) increasingly necessary in today’s competitive electricity market. In this paper, an enhanced biogeography-based optimization (BBO) referred to as POLBBO is proposed to solve the DED problem with valve-point effects. BBO is a relatively new powerful population-based meta-heuristic algorithm inspired by biogeography and has been extensively applied to many scientific and engineering problems. However, its direct-copying-based migration and random mutation operators make BBO possess good local exploitation ability but lack enough global exploration ability. To remedy the defect, on one hand, an efficient operator named polyphyletic migration operator is proposed to enhance the search ability of POLBBO. This operator can not only generate new features from more promising areas in the search space, but also effectively increase the population diversity. On the other hand, an orthogonal learning (OL) strategy based on orthogonal experimental design is presented. The OL strategy can quickly discover useful information from the search experiences and effectively utilize the information to construct a more promising solution, and thereby provide a systematic and elaborate reasoning method to guide the search directions of POLBBO. In addition, an effective simultaneous constraints handling technique without penalty factor settings is developed to handle various complicated constraints of the DED problem. Finally, four test

  9. The amphibians and reptiles of Mindanao Island, southern Philippines, II: the herpetofauna of northeast Mindanao and adjacent islands

    Directory of Open Access Journals (Sweden)

    Marites B. Sanguila

    2016-10-01

    Full Text Available We summarize all available amphibian and reptile species distribution data from the northeast Mindanao faunal region, including small islands associated with this subcenter of endemic vertebrate biodiversity. Together with all publicly available historical information from biodiversity repositories, we present new data from several major herpetological surveys, including recently conducted inventories on four major mountains of northeast Mindanao, and adjacent islands of Camiguin Sur, Dinagat, and Siargao. We present species accounts for all taxa, comment on unresolved taxonomic problems, and provide revisions to outdated IUCN conservation status assessments in cases where our new data significantly alter earlier classification status summaries. Together, our comprehensive analysis of this fauna suggests that the greater Mindanao faunal region possesses distinct subcenters of amphibian and reptile species diversity, and that until this area is revisited and its fauna and actually studied, with on-the-ground field work including targeted surveys of species distributions coupled to the study their natural history, our understanding of the diversity and conservation status of southern Philippine herpetological fauna will remain incomplete. Nevertheless, the northeast Mindanao geographical area (Caraga Region appears to have the highest herpetological species diversity (at least 126 species of any comparably-sized Philippine faunal subregion.

  10. Ancient geographical gaps and paleo-climate shape the phylogeography of an endemic bird in the sky islands of southern India.

    Science.gov (United States)

    Robin, V V; Sinha, Anindya; Ramakrishnan, Uma

    2010-10-13

    Sky islands, formed by the highest reaches of mountain tracts physically isolated from one another, represent one of the biodiversity-rich regions of the world. Comparative studies of geographically isolated populations on such islands can provide valuable insights into the biogeography and evolution of species on these islands. The Western Ghats mountains of southern India form a sky island system, where the relationship between the island structure and the evolution of its species remains virtually unknown despite a few population genetic studies. We investigated how ancient geographic gaps and glacial cycles have partitioned genetic variation in modern populations of a threatened endemic bird, the White-bellied Shortwing Brachypteryx major, across the montane Shola forests on these islands and also inferred its evolutionary history. We used bayesian and maximum likelihood-based phylogenetic and population-genetic analyses on data from three mitochondrial markers and one nuclear marker (totally 2594 bp) obtained from 33 White-bellied Shortwing individuals across five islands. Genetic differentiation between populations of the species correlated with the locations of deep valleys in the Western Ghats but not with geographical distance between these populations. All populations revealed demographic histories consistent with population founding and expansion during the Last Glacial Maximum. Given the level of genetic differentiation north and south of the Palghat Gap, we suggest that these populations be considered two different taxonomic species. Our results show that the physiography and paleo-climate of this region historically resulted in multiple glacial refugia that may have subsequently driven the evolutionary history and current population structure of this bird. The first avian genetic study from this biodiversity hotspot, our results provide insights into processes that may have impacted the speciation and evolution of the endemic fauna of this region.

  11. Ancient geographical gaps and paleo-climate shape the phylogeography of an endemic bird in the sky islands of southern India.

    Directory of Open Access Journals (Sweden)

    V V Robin

    2010-10-01

    Full Text Available Sky islands, formed by the highest reaches of mountain tracts physically isolated from one another, represent one of the biodiversity-rich regions of the world. Comparative studies of geographically isolated populations on such islands can provide valuable insights into the biogeography and evolution of species on these islands. The Western Ghats mountains of southern India form a sky island system, where the relationship between the island structure and the evolution of its species remains virtually unknown despite a few population genetic studies.We investigated how ancient geographic gaps and glacial cycles have partitioned genetic variation in modern populations of a threatened endemic bird, the White-bellied Shortwing Brachypteryx major, across the montane Shola forests on these islands and also inferred its evolutionary history. We used bayesian and maximum likelihood-based phylogenetic and population-genetic analyses on data from three mitochondrial markers and one nuclear marker (totally 2594 bp obtained from 33 White-bellied Shortwing individuals across five islands. Genetic differentiation between populations of the species correlated with the locations of deep valleys in the Western Ghats but not with geographical distance between these populations. All populations revealed demographic histories consistent with population founding and expansion during the Last Glacial Maximum. Given the level of genetic differentiation north and south of the Palghat Gap, we suggest that these populations be considered two different taxonomic species.Our results show that the physiography and paleo-climate of this region historically resulted in multiple glacial refugia that may have subsequently driven the evolutionary history and current population structure of this bird. The first avian genetic study from this biodiversity hotspot, our results provide insights into processes that may have impacted the speciation and evolution of the endemic fauna of

  12. Post-Inflationary Gravitino Production Revisited

    CERN Document Server

    Ellis, John; Nanopoulos, Dimitri V.; Olive, Keith A.; Peloso, Marco

    2016-01-01

    We revisit gravitino production following inflation. As a first step, we review the standard calculation of gravitino production in the thermal plasma formed at the end of post-inflationary reheating when the inflaton has completely decayed. Next we consider gravitino production prior to the completion of reheating, assuming that the inflaton decay products thermalize instantaneously while they are still dilute. We then argue that instantaneous thermalization is in general a good approximation, and also show that the contribution of non-thermal gravitino production via the collisions of inflaton decay products prior to thermalization is relatively small. Our final estimate of the gravitino-to-entropy ratio is approximated well by a standard calculation of gravitino production in the post-inflationary thermal plasma assuming total instantaneous decay and thermalization at a time $t \\simeq 1.2/\\Gamma_\\phi$. Finally, in light of our calculations, we consider potential implications of upper limits on the gravitin...

  13. Revisiting R-invariant direct gauge mediation

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Cheng-Wei [Center for Mathematics and Theoretical Physics andDepartment of Physics, National Central University,Taoyuan, Taiwan 32001, R.O.C. (China); Institute of Physics, Academia Sinica,Taipei, Taiwan 11529, R.O.C. (China); Physics Division, National Center for Theoretical Sciences,Hsinchu, Taiwan 30013, R.O.C. (China); Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); Harigaya, Keisuke [Department of Physics, University of California,Berkeley, California 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, California 94720 (United States); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Ibe, Masahiro [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan); ICRR, University of Tokyo,Kashiwa, Chiba 277-8582 (Japan); Yanagida, Tsutomu T. [Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8583 (Japan)

    2016-03-21

    We revisit a special model of gauge mediated supersymmetry breaking, the “R-invariant direct gauge mediation.” We pay particular attention to whether the model is consistent with the minimal model of the μ-term, i.e., a simple mass term of the Higgs doublets in the superpotential. Although the incompatibility is highlighted in view of the current experimental constraints on the superparticle masses and the observed Higgs boson mass, the minimal μ-term can be consistent with the R-invariant gauge mediation model via a careful choice of model parameters. We derive an upper limit on the gluino mass from the observed Higgs boson mass. We also discuss whether the model can explain the 3σ excess of the Z+jets+E{sub T}{sup miss} events reported by the ATLAS collaboration.

  14. The Faraday effect revisited General theory

    CERN Document Server

    Cornean, H D; Pedersen, T G

    2005-01-01

    This paper is the first in a series revisiting the Faraday effect, or more generally, the theory of electronic quantum transport/optical response in bulk media in the presence of a constant magnetic field. The independent electron approximation is assumed. For free electrons, the transverse conductivity can be explicitly computed and coincides with the classical result. In the general case, using magnetic perturbation theory, the conductivity tensor is expanded in powers of the strength of the magnetic field $B$. Then the linear term in $B$ of this expansion is written down in terms of the zero magnetic field Green function and the zero field current operator. In the periodic case, the linear term in $B$ of the conductivity tensor is expressed in terms of zero magnetic field Bloch functions and energies. No derivatives with respect to the quasimomentum appear and thereby all ambiguities are removed, in contrast to earlier work.

  15. Revisiting instanton corrections to the Konishi multiplet

    Energy Technology Data Exchange (ETDEWEB)

    Alday, Luis F. [Mathematical Institute, University of Oxford,Andrew Wiles Building, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG (United Kingdom); Korchemsky, Gregory P. [Institut de Physique Théorique, Université Paris Saclay, CNRS, CEA,F-91191 Gif-sur-Yvette (France)

    2016-12-01

    We revisit the calculation of instanton effects in correlation functions in N=4 SYM involving the Konishi operator and operators of twist two. Previous studies revealed that the scaling dimensions and the OPE coefficients of these operators do not receive instanton corrections in the semiclassical approximation. We go beyond this approximation and demonstrate that, while operators belonging to the same N=4 supermultiplet ought to have the same conformal data, the evaluation of quantum instanton corrections for one operator can be mapped into a semiclassical computation for another operator in the same supermultiplet. This observation allows us to compute explicitly the leading instanton correction to the scaling dimension of operators in the Konishi supermultiplet as well as to their structure constants in the OPE of two half-BPS scalar operators. We then use these results, together with crossing symmetry, to determine instanton corrections to scaling dimensions of twist-four operators with large spin.

  16. Revisiting kaon physics in general Z scenario

    Directory of Open Access Journals (Sweden)

    Motoi Endo

    2017-08-01

    Full Text Available New physics contributions to the Z penguin are revisited in the light of the recently-reported discrepancy of the direct CP violation in K→ππ. Interference effects between the standard model and new physics contributions to ΔS=2 observables are taken into account. Although the effects are overlooked in the literature, they make experimental bounds significantly severer. It is shown that the new physics contributions must be tuned to enhance B(KL→π0νν¯, if the discrepancy of the direct CP violation is explained with satisfying the experimental constraints. The branching ratio can be as large as 6×10−10 when the contributions are tuned at the 10% level.

  17. Sparse random matrices: The eigenvalue spectrum revisited

    International Nuclear Information System (INIS)

    Semerjian, Guilhem; Cugliandolo, Leticia F.

    2003-08-01

    We revisit the derivation of the density of states of sparse random matrices. We derive a recursion relation that allows one to compute the spectrum of the matrix of incidence for finite trees that determines completely the low concentration limit. Using the iterative scheme introduced by Biroli and Monasson [J. Phys. A 32, L255 (1999)] we find an approximate expression for the density of states expected to hold exactly in the opposite limit of large but finite concentration. The combination of the two methods yields a very simple geometric interpretation of the tails of the spectrum. We test the analytic results with numerical simulations and we suggest an indirect numerical method to explore the tails of the spectrum. (author)

  18. Neutrino dark energy. Revisiting the stability issue

    Energy Technology Data Exchange (ETDEWEB)

    Eggers Bjaelde, O.; Hannestad, S. [Aarhus Univ. (Denmark). Dept. of Physics and Astronomy; Brookfield, A.W. [Sheffield Univ. (United Kingdom). Dept. of Applied Mathematics and Dept. of Physics, Astro-Particle Theory and Cosmology Group; Van de Bruck, C. [Sheffield Univ. (United Kingdom). Dept. of Applied Mathematics, Astro-Particle Theory and Cosmology Group; Mota, D.F. [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik]|[Institute of Theoretical Astrophysics, Oslo (Norway); Schrempp, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Tocchini-Valentini, D. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy

    2007-05-15

    A coupling between a light scalar field and neutrinos has been widely discussed as a mechanism for linking (time varying) neutrino masses and the present energy density and equation of state of dark energy. However, it has been pointed out that the viability of this scenario in the non-relativistic neutrino regime is threatened by the strong growth of hydrodynamic perturbations associated with a negative adiabatic sound speed squared. In this paper we revisit the stability issue in the framework of linear perturbation theory in a model independent way. The criterion for the stability of a model is translated into a constraint on the scalar-neutrino coupling, which depends on the ratio of the energy densities in neutrinos and cold dark matter. We illustrate our results by providing meaningful examples both for stable and unstable models. (orig.)

  19. Re-visiting the electrophysiology of language.

    Science.gov (United States)

    Obleser, Jonas

    2015-09-01

    This editorial accompanies a special issue of Brain and Language re-visiting old themes and new leads in the electrophysiology of language. The event-related potential (ERP) as a series of characteristic deflections ("components") over time and their distribution on the scalp has been exploited by speech and language researchers over decades to find support for diverse psycholinguistic models. Fortunately, methodological and statistical advances have allowed human neuroscience to move beyond some of the limitations imposed when looking at the ERP only. Most importantly, we currently witness a refined and refreshed look at "event-related" (in the literal sense) brain activity that relates itself more closely to the actual neurobiology of speech and language processes. It is this imminent change in handling and interpreting electrophysiological data of speech and language experiments that this special issue intends to capture. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Causes of endemic radiation in the Caribbean: evidence from the historical biogeography and diversification of the butterfly genus Calisto (Nymphalidae: Satyrinae: Satyrini)

    Czech Academy of Sciences Publication Activity Database

    Matos Maravi, Pavel F.; Núňez Águila, R.; Peňa, C.; Miller, J.; Sourakov, A.; Wahlberg, N.

    2014-01-01

    Roč. 14, 1 /article number 199/ (2014) ISSN 1471-2148 Grant - others:GA JU(CZ) 156/2013/P; National Geographic Society(US) 5717-96 Institutional support: RVO:60077344 Keywords : Caribbean * ecological limits * historical biogeography Subject RIV: EH - Ecology, Behaviour Impact factor: 3.368, year: 2014 http://www.biomedcentral.com/content/pdf/s12862-014-0199-7.pdf

  1. Post-fire diversity and abundance in pine and eucalipt stands in Portugal: effects of biogeography, topography, forest type and post-fire management

    OpenAIRE

    Maia, P.; Keizer, J.; Vasques, A.; Abrantes, N.; Roxo, L.; Fernandes, P.; Ferreira, A.; Moreira, F.

    2014-01-01

    This study concerned the mid-term regeneration of the woody understory vegetation of pure and mixed stands of Pinus pinaster Ait. and Eucalyptus globulus Labill. in northern and central Portugal following wildfires in 2005 and 2006. Pine and eucalypt stands are the most widespread and most fire-prone forest types in Portugal. The main aim was to investigate the importance of biogeography, topography, forest type and post-fire management operations in explaining the patterns in shr...

  2. Island solution; Inselloesung

    Energy Technology Data Exchange (ETDEWEB)

    Bah, Isaac

    2013-06-15

    On the Azores island Graciosa the Berlin-based company Younicos has installed a new electricity system with advanced storage technology, which will make the islanders independent from fossil fuels. With an energy mix of wind power, photovoltaics and biomass the dependence on fossil fuels should be terminated. In the center of the flagship project specifically developed hybrid batteries are used (combination of sodium-sulfur- and lithium-ion batteries) with 2.7 MW of power and a storage capacity of ten megawatts hours. [German] Auf der Azoren-Insel Graciosa installiert das Berliner Unternehmen Younicos ein neues Stromsystem mit modernster Speichertechnologie, das die Bewohner unabhaengig von fossilen Energietraegern machen soll. Mit einem Energiemix aus Windkraft, Photovoltaik und Biomasse soll die Abhaengigkeit von fossilen Brennstoffen beendet werden. Im Zentrum des Vorzeigeprojekts stehen speziell fuer den Inseleinsatz entwickelte Hybridbatterien (Kombination aus Natrium-Schwefel- und Lithium-Ionen-Akkus) mit 2,7 Megawatt Leistung und eine Speicherkapazitaet von zehn Megawattestunden.

  3. Urban heat island 1

    DEFF Research Database (Denmark)

    Bühler, Oliver; Jensen, Marina Bergen; Petersen, Karen Sejr

    2010-01-01

    Urban Heat Island beskriver det forhold, at temperaturen i byområder er højere end temperaturen i tilgrænsede landområder. Årsagen hertil ligger i den urbane arealanvendelse, hvor en mindre andel af arealerne er dækket af vegetation, og en større andel består af forseglede arealer.......Urban Heat Island beskriver det forhold, at temperaturen i byområder er højere end temperaturen i tilgrænsede landområder. Årsagen hertil ligger i den urbane arealanvendelse, hvor en mindre andel af arealerne er dækket af vegetation, og en større andel består af forseglede arealer....

  4. Charge Islands Through Tunneling

    Science.gov (United States)

    Robinson, Daryl C.

    2002-01-01

    It has been recently reported that the electrical charge in a semiconductive carbon nanotube is not evenly distributed, but rather it is divided into charge "islands." This paper links the aforementioned phenomenon to tunneling and provides further insight into the higher rate of tunneling processes, which makes tunneling devices attractive. This paper also provides a basis for calculating the charge profile over the length of the tube so that nanoscale devices' conductive properties may be fully exploited.

  5. Islands in the Ocean

    Directory of Open Access Journals (Sweden)

    Elena Bagina

    2017-12-01

    Full Text Available Today’s China is an outpost of modern western architecture. All famous architects and firms build here. Having lost their historical context, the objects of traditional Chinese architecture become islands in the ocean of new development. Their destiny is controversial. Architectural masterpieces are perceived in a superficial manner not only by tourists, but also by local people. The link of times that used to be cherished in Chinese culture is being broken today.

  6. Biogeography of Old World emballonurine bats (Chiroptera: Emballonuridae) inferred with mitochondrial and nuclear DNA.

    Science.gov (United States)

    Ruedi, Manuel; Friedli-Weyeneth, Nicole; Teeling, Emma C; Puechmaille, Sébastien J; Goodman, Steven M

    2012-07-01

    Extant bats of the genus Emballonura have a trans-Indian Ocean distribution, with two endemic species restricted to Madagascar, and eight species occurring in mainland southeast Asia and islands in the western Pacific Ocean. Ancestral Emballonura may have been more widespread on continental areas, but no fossil identified to this genus is known from the Old World. Emballonura belongs to the subfamily Emballonurinae, which occurs in the New and Old World. Relationships of all Old World genera of this subfamily, including Emballonura and members of the genera Coleura from Africa and western Indian Ocean islands and Mosia nigrescens from the western Pacific region, are previously unresolved. Using 1833 bp of nuclear and mitochondrial genes, we reconstructed the phylogenetic history of Old World emballonurine bats. We estimated that these lineages diverged around 30 million years ago into two monophyletic sister groups, one represented by the two taxa of Malagasy Emballonura, Coleura and possibly Mosia, and the other by a radiation of Indo-Pacific Emballonura, hence, rendering the genus Emballonura paraphyletic. The fossil record combined with these phylogenetic relationships suggest at least one long-distance dispersal event across the Indian Ocean, presumably of African origin, giving rise to all Indo-Pacific Emballonura species (and possibly Mosia). Cladogenesis of the extant Malagasy taxa took place during the Quaternary giving rise to two vicariant species, E. atrata in the humid east and E. tiavato in the dry west. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. MARICULTURE ON CROATIAN ISLANDS

    Directory of Open Access Journals (Sweden)

    Gordana Šarušić

    2000-09-01

    Full Text Available The first attempts of intensive mariculture in Croatia commenced at the very beginning of 1980’s. The mid-eighties brought an expansion of mariculture production, which has been continuously increasing. A few different marine organisms are intensively cultured - both fish and shellfish. Among them commercially most important and highly valued species are sea bass Dicentrarchus labrax and sea bream Sparus aurata. Mussel Mytilus galloprovincialis and oyster Ostrea edulis are the most important shellfish. Fish species such as dentex Dentex dentex, red sea bream Pagrus major and sheepshead bream Puntazzo puntazzo are reared too, but in a rather small quantities. Only recently the rearing, on-growing- of bluefin tuna Thunnus thynnus started in Croatia. The juveniles (70% are reared in a Croatian hatcheries, and 30% has to be imported mainly from Italy and France, due to a higher demand for this kind of culture among the small growers. Croatian part of Adriatic sea possesses a number of geomorfologicaly suitable sites and meteorological conditions which determined the choice - type - of intensive culture. All fish species are reared in a floating cages. The choice of cages i. e. semi off-shore or floating frames, size, rearing volume and design depend on the investors personal preference. The annual turnouf of a market size bass was about 600t and 300t bream in 1996., by 10 island farms which is 70% of total production in Croatia. Including other cultured fish species last year production was up to 1000t, and it™s being estimated to be about 1300t in the following year. The shellfish production on the islands is usually individual attempt of farmers, producing minor quantities mostly in polyculture. This production has bigger potential but it’s limited owing to the EU quality control regulations which do not allow the export, and by domestic market which has drastically decreased due to the collapse of tourism during the recent war. Almost 80

  8. Evidence for the Fundamental Difference Hypothesis or Not?: Island Constraints Revisited

    Science.gov (United States)

    Belikova, Alyona; White, Lydia

    2009-01-01

    This article examines how changes in linguistic theory affect the debate between the fundamental difference hypothesis and the access-to-Universal Grammar (UG) approach to SLA. With a focus on subjacency (Chomsky, 1973), a principle of UG that places constraints on "wh"-movement and that has frequently been taken as a test case for verifying…

  9. Holocene reef building on eastern St. Croix, US Virgin Islands: Lang Bank revisited

    Science.gov (United States)

    Hubbard, D. K.; Gill, I. P.; Burke, R. B.

    2013-09-01

    New core and seismic data suggest that widespread reef building started on Lang Bank by 8,900 CalBP and was dominated by Acropora palmata for the next three millennia. Accretion rates averaged 5.81 m ky-1, a rate that was sufficient for reefs to keep pace with rising sea level on the bank throughout their history. Seismic data show a deep platform interior that was flooded well in advance of reef building along the elevated rim. As a result, those reefs were buffered from sediment stress by their higher positions and active water flow to the west. A. palmata disappeared from the shallow margin by 6,350 yr ago, and reef building on Lang Bank largely ceased by 5,035 CalBP. The reasons for these dramatic events are unclear. Water depth over the reefs was generally shallower than when they started to build, and sea level was slowing dramatically. The new data described here show that reefs flourished on Lang Bank throughout the hiatus suggested by earlier studies (10-7 kyrs BP), and the ultimate demise of shelf-edge reefs is clearly not associated with either poor water quality or sudden sea-level rise. In addition, accretion rates from eastern St. Croix and throughout the Caribbean were well below the high values (≥10 m ky-1) that have been widely assumed. These data collectively argue against models that require extreme environmental or oceanographic phenomena to drown reefs on Lang Bank where reef building was too fast to be outpaced by Holocene sea-level rise. This also bears on more generalized Caribbean models that depend on the presumed reef history on eastern St. Croix.

  10. Microbial Mats on the Orkney Islands Revisited: Microenvironment and Microbial Community Composition

    DEFF Research Database (Denmark)

    Wieland, A.; Kühl, M.; McGowan, L.

    2003-01-01

    of these sediments. High amounts of algal lipids and slightly higher numbers (genera, abundances) of cyanobacteria were found in Waulkmill Bay mats. However, overall only a few genera and low numbers of unicellular and filamentous cyanobacteria were present in mats from Waulkmill and Swanbister beach, as deduced...... fragment length polymorphism) analysis in Swanbister beach mats, the depth distribution of different populations of purple and sulfate-reducing bacteria could be related to the microenvironmental conditions. Oxygen, but also sulfide and other (inorganic and organic) sulfur compounds, seems to play...

  11. Revisiting Caveiro Lake sediment record: the Holocene NAO and AMO impact on Pico Island (Azores archipelago)

    Science.gov (United States)

    Hernandez, A.; Giralt, S.; Raposeiro, P. M.; Gonçalves, V. M.; Pueyo, J. J.; Trigo, R. M.; Bao, R.; Sáez, A.

    2017-12-01

    Northern Hemisphere climate is partly conditioned by a number of atmospheric and oceanic patterns which occur in the North Atlantic sector. The favourable location of the Azores Archipelago (37°-40° N, 25°-31° W) results in a privileged place to generate high-resolution Holocene climatic proxy data that can contribute to deep our understanding on the evolution of these atmospheric and oceanic patterns. In the frame of three research projects, namely PALEONAO (CGL2010-15767), RAPIDNAO (CGL2013-40608-R) and PALEOMODES (CGL2016-75281-C2), high-resolution proxy-based reconstructions from Azores Archipelago have recently shown a combined impact of atmospheric and oceanic patterns at multiannual and decadal time-scales (Rubio-Inglés et al. 2016; Hernández et al. 2017). However, the long-term evolution coupling/uncoupling of these patterns is not well-determined yet. Here, we present a new high-resolution climate reconstruction based on the Caveiro Lake sedimentary sequence in order to fill this gap. Previously, Björck et al. (2006) studied a section of this sequence (the uppermost 4.6 m covering last 6 Ka cal BP) concluding that changes in the thermohaline circulation and the SST were the main drivers in the long-term precipitation variability, whereas the NAO impact was the main atmospheric driver of short-term precipitation changes. However, they only distinguished the NAO impact for the last 600 years owing to the low resolution of the study for the lower portion of the core. The new studied sequence (8.40 m long, 8.2 Ka cal BP) has been analysed at decadal-to centennial time-scale resolution for X-ray diffraction (XRD), X-ray fluorescence (XRF) core scanning and elemental and isotope geochemistry on bulk organic matter. The statistical multivariate analysis of the data highlights the main drivers triggering the sedimentary infill of the lake would be the NAO and AMO by controlling the lacustrine productivity via nutrients input. This new high-resolution climate reconstruction from Caveiro Lake disentangles the combined influences of the NAO and AMO through the Holocene at decadal-to-centennial time scales. References Björck et al. (2006) - Quat Sci Rev 25, 9-32. Rubio-Inglés et al. (2016) - AGU fall meeting, PP51A­-2287. Hernández et al. (2017) - Glob Planet Change 154, 61-74.

  12. Island life in the Cretaceous - faunal composition, biogeography, evolution, and extinction of land-living vertebrates on the Late Cretaceous European archipelago

    OpenAIRE

    Csiki Sava,Zoltan; Buffetaut,Eric; Ősi,Attila; Pereda-Suberbiola,Xabier; Brusatte,Stephen

    2015-01-01

    Abstract The Late Cretaceous was a time of tremendous global change, as the final stages of the Age of Dinosaurs were shaped by climate and sea level fluctuations and witness to marked paleogeographic and faunal changes, before the end-Cretaceous bolide impact. The terrestrial fossil record of Late Cretaceous Europe is becoming increasingly better understood, based largely on intensive fieldwork over the past two decades, promising new insights into latest Cretaceous faunal evolution. We revi...

  13. Self-sustained magnetic islands

    Energy Technology Data Exchange (ETDEWEB)

    Chatenet, J H; Luciani, J F [Ecole Polytechnique, 91 - Palaiseau (France); Garbet, X [Association Euratom-CEA, Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    1996-06-01

    Numerical simulations of a single magnetic island evolution are presented in the regime where the island width is smaller than an ion Larmor radius. It is shown that the island rotation is controlled by particle diffusion due to collisions or a background of microturbulence. As expected from the theory of a stationary island, there exist cases where linearly stable magnetic perturbation are nonlinearly self-sustained. This situation corresponds to large poloidal beta and temperature gradient. The drive is due to diamagnetic frequency effects. However, this situation is not generic, and islands can also decay. It is found that a magnetic island is self-sustained for a negative off-diagonal diffusion coefficient. This case occurs in a tokamak if the inward particle pinch is due to the temperature gradient. (author). 30 refs.

  14. Self-sustained magnetic islands

    International Nuclear Information System (INIS)

    Chatenet, J.H.; Luciani, J.F.; Garbet, X.

    1996-06-01

    Numerical simulations of a single magnetic island evolution are presented in the regime where the island width is smaller than an ion Larmor radius. It is shown that the island rotation is controlled by particle diffusion due to collisions or a background of microturbulence. As expected from the theory of a stationary island, there exist cases where linearly stable magnetic perturbation are nonlinearly self-sustained. This situation corresponds to large poloidal beta and temperature gradient. The drive is due to diamagnetic frequency effects. However, this situation is not generic, and islands can also decay. It is found that a magnetic island is self-sustained for a negative off-diagonal diffusion coefficient. This case occurs in a tokamak if the inward particle pinch is due to the temperature gradient. (author)

  15. Dilmun revisited: excavations at Saar, Bahrain

    Directory of Open Access Journals (Sweden)

    Harriet Crawford

    1997-11-01

    Full Text Available About 2000 BC the island of Bahrain was at the centre of a prosperous trading community - the Early Dilmun civilization - that stretched from Mesopotamia to the Indus Valley. Excavations at the site of Saar have, since 1989, recovered much new information about the layout of the settlement and its local economy and social system.

  16. Demographic Ageing on Croatian Islands

    Directory of Open Access Journals (Sweden)

    Ivo Nejašmić

    2013-08-01

    Full Text Available This paper analyses the changes in the population structure of the Croatian islands by age, warns of the degree of ageing, provides spatial differentiation of this process and presents perspective of ageing at the level of settlement. Typing of population ageing is based on scores and has seven types. The total island population in 2011 belongs to the type 5 – very old population. Almost a half of the settlements (out of 303 have been affected by the highest levels of ageing (types 6 and 7. It was found that a quarter of island settlements will become “dead villages” in a foreseeable future; most of them are on small islands but also in the interior of larger islands. These are villages decaying in every respect, in which the way of life, as we know it, veins and goes out. The present ageing villagers are their last residents in most cases. Eve¬rything suggests that demographic recovery of the islands is not possible with the forces in situ. It is important to strike a balance between the needs and opportunities in order to successfully organize life on the islands, both small and large ones, and the fact is that there is a continuing disparity, which is especially profound in small islands. A sensitive and selective approach is needed to overcome the unfavourable demographic trends. Therefore it is necessary to respect the particularities of indi¬vidual islands and island groups in devising development strategy. Solutions to the problems must come of the local and wider community in synergy with relevant professional and scientific institutions. However, if the solutions are not found or measures do not give results, if the islands are left to desorganisation and senilisation, a part of the islands will become a wasteland. With regard to the value of this area whose wealth are people in the first place, this would be an intolerable civilization decline.

  17. Renewable energy islands in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard, Iben [ed.

    1998-12-31

    This publication includes a compiled presentation of various aspects concerning the possible transformation of some European islands into renewable energy communities and these projects were presented by a selection of pioneer islands at the first European Seminar on Renewable Energy Islands, held on the Danish island of Samsoee, 29-30 June 1998. This issue has increased in importance with the presentation of the ambitious EU-White Paper: `Energy for the future: Renewable Sources of Energy` which was adopted in 1998. One of the key elements of the strategy for an accelerated implementation of renewable energy is to transform 100 localities within Europe into communities which are to be 100% self-sufficient with renewable energy before 2010. In line with this strategy, the Danish Government appointed the island of Samsoe towards the end of 1997 to be the first `official` Danish, renewable energy island. This is to serve as a demonstration project for other local communities, both in Denmark as well as in the rest Europe. Gothland, Madeira, Canary Islands, Cape Verde, Arki, Crete, Minorca and Orkney Islands were represented. Environmental advantages of wind, solar and wave power for distant island communities were indicated. Serious savings would be achieved by limitation of fossil fuel import and utilization of local resources. (EG)

  18. Biogeografía marina de Chile continental Marine biogeography of continental Chile

    Directory of Open Access Journals (Sweden)

    PATRICIO A. CAMUS

    2001-09-01

    literature review on the marine biogeography of Chile and related subjects, with the following objectives: (a to summarize the oceanographic, climatic and geomorphologic characteristics of the Chilean continental coast; (b to discuss 27 biogeographic classifications published for the Chilean coast, analyzing both the procedures and criteria used by their authors, along with their main conclusions and agreements; (c to assess the vicariant and dispersal processes associated with the displacement and modification of the regional biotas, regarding the available antecedentes on the prevailing conditions and main events during the Tertiary and Quaternary periods; and (d to propose a scenario of biogeographic change based on historical determinants and their influence on the formation, character, and dynamics of biotas along the Chilean coast, emphasizing the identification and biogeographic nature of the main spatial units. From the preceding information, I propose a hypothesis of biogeographic classification for the level of biotas, not necessarily coincident with prior studies at lower levels such as flora or fauna. This classification identifies three major spatial units: a southern area which comprises an austral biota (Magellan Province, a northern area which comprises a warm-temperate biota (Peruvian Province, and a non transitional, Intermediate Area including mixed components of biota and exhibiting a poor biogeographic definition of both its character and hierarchical rank. I also discuss the different nature of two transitional zones located at the boundaries of the Intermediate Area, a southward induced transition and a northward contact transition, likely produced by the migration of biotas and glacial-tectonic events, respectively

  19. The diversity and biogeography of Western Indian Ocean reef-building corals.

    Directory of Open Access Journals (Sweden)

    David Obura

    Full Text Available This study assesses the biogeographic classification of the Western Indian Ocean (WIO on the basis of the species diversity and distribution of reef-building corals. Twenty one locations were sampled between 2002 and 2011. Presence/absence of scleractinian corals was noted on SCUBA, with the aid of underwater digital photographs and reference publications for species identification. Sampling effort varied from 7 to 37 samples per location, with 15 to 45 minutes per dive allocated to species observations, depending on the logistics on each trip. Species presence/absence was analyzed using the Bray-Curtis similarity coefficient, followed by cluster analysis and multi-dimensional scaling. Total (asymptotic species number per location was estimated using the Michaelis-Menten equation. Three hundred and sixty nine coral species were named with stable identifications and used for analysis. At the location level, estimated maximum species richness ranged from 297 (Nacala, Mozambique to 174 (Farquhar, Seychelles. Locations in the northern Mozambique Channel had the highest diversity and similarity, forming a core region defined by its unique oceanography of variable meso-scale eddies that confer high connectivity within this region. A distinction between mainland and island fauna was not found; instead, diversity decreased radially from the northern Mozambique Channel. The Chagos archipelago was closely related to the northern Mozambique Channel region, and analysis of hard coral data in the IUCN Red List found Chagos to be more closely related to the WIO than to the Maldives, India and Sri Lanka. Diversity patterns were consistent with primary oceanographic drivers in the WIO, reflecting inflow of the South Equatorial Current, maintenance of high diversity in the northern Mozambique Channel, and export from this central region to the north and south, and to the Seychelles and Mascarene islands.

  20. Myrteae phylogeny, calibration, biogeography and diversification patterns: Increased understanding in the most species rich tribe of Myrtaceae.

    Science.gov (United States)

    Vasconcelos, Thais N C; Proença, Carol E B; Ahmad, Berhaman; Aguilar, Daniel S; Aguilar, Reinaldo; Amorim, Bruno S; Campbell, Keron; Costa, Itayguara R; De-Carvalho, Plauto S; Faria, Jair E Q; Giaretta, Augusto; Kooij, Pepijn W; Lima, Duane F; Mazine, Fiorella F; Peguero, Brigido; Prenner, Gerhard; Santos, Matheus F; Soewarto, Julia; Wingler, Astrid; Lucas, Eve J

    2017-04-01

    Myrteae (c. 2500 species; 51 genera) is the largest tribe of Myrtaceae and an ecologically important groups of angiosperms in the Neotropics. Systematic relationships in Myrteae are complex, hindering conservation initiatives and jeopardizing evolutionary modelling. A well-supported and robust phylogenetic hypothesis was here targeted towards a comprehensive understanding of the relationships within the tribe. The resultant topology was used as a base for key evolutionary analyses such as age estimation, historical biogeography and diversification rate patterns. One nuclear (ITS) and seven chloroplast (psbA-trnH, matK, ndhF, trnl-trnF, trnQ-rps16, rpl16 and rpl32-trnL) DNA regions for 115 taxa representing 46 out of the 51 genera in the tribe were accessed and analysed using maximum likelihood and Bayesian inference tools for phylogenetic reconstruction. Dates of diversification events were estimated and contrasted using two distinct fossil sets (macro and pollen) in BEAST. The subsequent dated phylogenies were compared and analysed for biogeographical patterns using BioGeoBEARS and diversification rates using BAMM. Myrteae phylogeny presents strong statistical support for three major clades within the tribe: Australasian group, Myrtus group and Main Neotropical Lineage. Dating results from calibration using macrofossil are an average of 20 million years older and show an early Paleocene origin of Myrteae, against a mid-Eocene one from the pollen fossil calibration. Biogeographic analysis shows the origin of Myrteae in Zealandia in both calibration approaches, followed by a widespread distribution throughout the still-linked Gondwana continents and diversification of Neotropical endemic lineages by later vicariance. Best configuration shift indicates three points of acceleration in diversification rates, all of them occurring in the Main Neotropical Lineage. Based on the reconstructed topology, several new taxonomic placements were recovered, including: the

  1. Organizations as Designed Islands

    Directory of Open Access Journals (Sweden)

    Pasquale Gagliardi

    2009-05-01

    Full Text Available The literature and practice of organizational design are mostly based on simplistic conceptions which ignore recent theoretical developments in organizational studies. Conceiving of organizations as ‘designed islands’, it is argued, can contribute to a more solid theoretical foundation to organization theory, viewed as normative science. Relying on the work of Peter Sloterdijk, who describes the forms of life in space in terms of spheres, the heuristic power of the island metaphor is explored. What can be learnt from the art of isolating in order to construct lived organizational environments is then discussed, and the paradoxical relationship between connection and isolation is highlighted.

  2. Three Mile Island

    International Nuclear Information System (INIS)

    Wood, M.S.; Shultz, S.M.

    1988-01-01

    This bibliography is divided into the following categories: Accident Overviews, Sequence and Causes; International Commentary and Reaction; Emergency Preparedness and Disaster Planning; Health Effects; Radioactive Releases and the Environment; Accident Investigations/Commissions; Nuclear Industry: Safety, Occupational, and Financial Issues; Media and Communications; Cleanup; Sociopolitical Response and Commentary; Restart; Legal Ramifications; Federal Documents: President's Commission on the Accident at Three Mile Island; Federal Documents: Nuclear Regulatory Commission; Federal Documents: United States Department of Energy; Federal Documents: Miscellaneous Reports; Pennsylvania State Documents; Federal and State Hearings; and Popular Literature

  3. Weather In Some Islands

    Institute of Scientific and Technical Information of China (English)

    王良华

    2007-01-01

    There are four seasons in a year. When spring comes, the weather is mild(温和的). Summer comes after spring. Summer is the hottest season of the year. Autumn follows summer. It is the best season of the year. Winter is the coldest season of the year. Some islands(岛) have their own particular(特别的) seasons because their weather is very much affected(影响) by the oceans(海洋) around them. In Britain, winter is not very cold and summer is not very hot.

  4. Islands and non-islands in native and heritage Korean

    Directory of Open Access Journals (Sweden)

    Boyoung eKim

    2016-02-01

    Full Text Available To a large extent, island phenomena are cross-linguistically invariable, but English and Korean present some striking differences in this domain. English has wh-movement and Korean does not, and while both languages show sensitivity to wh-islands, only English has island effects for adjunct clauses. Given this complex set of differences, one might expect Korean/English bilinguals, and especially heritage Korean speakers (i.e. early bilinguals whose L2 became their dominant language during childhood to be different from native speakers, since heritage speakers have had more limited exposure to Korean, may have had incomplete acquisition and/or attrition, and may show significant transfer effects from the L2. Here we examine islands in heritage speakers of Korean in the U.S. Through a series of four formal acceptability experiments comparing these heritage speakers with native speakers residing in Korea, we show that the two groups are remarkably similar. Both show clear evidence for wh-islands and an equally clear lack of adjunct island effects. Given the very different linguistic environment that the heritage speakers have had since early childhood, this result lends support to the idea that island phenomena are largely immune to environmental influences and stem from deeper properties of the processor and/or grammar. Similarly, it casts some doubt on recent proposals that islands are learned from the input.

  5. Enjebi Island dose assessment

    International Nuclear Information System (INIS)

    Robison, W.L.; Conrado, C.L.; Phillips, W.A.

    1987-07-01

    We have updeated the radiological dose assessment for Enjebi Island at Enewetak Atoll using data derived from analysis of food crops grown on Enjebi. This is a much more precise assessment of potential doses to people resettling Enjebi Island than the 1980 assessment in which there were no data available from food crops on Enjebi. Details of the methods and data used to evaluate each exposure pathway are presented. The terrestrial food chain is the most significant potential exposure pathway and 137 Cs is the radionuclide responsible for most of the estimated dose over the next 50 y. The doses are calculated assuming a resettlement date of 1990. The average wholebody maximum annual estimated dose equivalent derived using our diet model is 166 mremy;the effective dose equivalent is 169 mremy. The estimated 30-, 50-, and 70-y integral whole-body dose equivalents are 3.5 rem, 5.1 rem, and 6.2 rem, respectively. Bone-marrow dose equivalents are only slightly higher than the whole-body estimates in each case. The bone-surface cells (endosteal cells) receive the highest dose, but they are a less sensitive cell population and are less sensitive to fatal cancer induction than whole body and bone marrow. The effective dose equivalents for 30, 50, and 70 y are 3.6 rem, 5.3 rem, and 6.6 rem, respectively. 79 refs., 17 figs., 24 tabs

  6. An Island Called Cuba

    Directory of Open Access Journals (Sweden)

    Jean Stubbs

    2011-06-01

    Full Text Available Review of: An Island Called Home: Returning to Jewish Cuba. Ruth Behar, photographs by Humberto Mayol. New Brunswick NJ: Rutgers University Press, 2007. xiii + 297 pp. (Cloth US$ 29.95 Fidel Castro: My Life: A Spoken Autobiography. Fidel Castro & Ignacio Ramonet. New York: Scribner/Simon & Schuster, 2008. vii + 724 pp. (Paper US$ 22.00, e-book US$ 14.99 Cuba: What Everyone Needs to Know. Julia E. Sweig. New York: Oxford University Press, 2009. xiv + 279 pp. (Paper US$ 16.95 [First paragraph] These three ostensibly very different books tell a compelling story of each author’s approach, as much as the subject matter itself. Fidel Castro: My Life: A Spoken Autobiography is based on a series of long interviews granted by the then-president of Cuba, Fidel Castro, to Spanish-Franco journalist Ignacio Ramonet. Cuba: What Everyone Needs to Know, by U.S. political analyst Julia Sweig, is one of a set country series, and, like Ramonet’s, presented in question/answer format. An Island Called Home: Returning to Jewish Cuba, with a narrative by Cuban-American anthropologist Ruth Behar and photographs by Cuban photographer Humberto Mayol, is a retrospective/introspective account of the Jewish presence in Cuba. While from Ramonet and Sweig we learn much about the revolutionary project, Behar and Mayol convey the lived experience of the small Jewish community against that backdrop.

  7. Monitoring developments in island waters

    International Nuclear Information System (INIS)

    Crellin, L.V.

    1995-01-01

    The environmental effects of islands in the Irish Sea of the offshore oil and gas industry are discussed in this paper, in particular on sand and gravel resources. This information is considered by the Department of Trade and Industry when granting prospecting, exploration and production licenses. Consultation between industry and islanders forms part of the license granting process. (UK)

  8. Islands for nuclear power stations

    International Nuclear Information System (INIS)

    Usher, E.F.F.W.; Fraser, A.P.

    1981-01-01

    The safety principles, design criteria and types of artificial island for an offshore nuclear power station are discussed with particular reference to siting adjacent to an industrial island. The paper concludes that the engineering problems are soluble and that offshore nuclear power stations will eventually be built but that much fundamental work is still required. (author)

  9. Pair Production Constraints on Superluminal Neutrinos Revisited

    International Nuclear Information System (INIS)

    Brodsky, Stanley

    2012-01-01

    We revisit the pair creation constraint on superluminal neutrinos considered by Cohen and Glashow in order to clarify which types of superluminal models are constrained. We show that a model in which the superluminal neutrino is effectively light-like can evade the Cohen-Glashow constraint. In summary, any model for which the CG pair production process operates is excluded because such timelike neutrinos would not be detected by OPERA or other experiments. However, a superluminal neutrino which is effectively lightlike with fixed p 2 can evade the Cohen-Glashow constraint because of energy-momentum conservation. The coincidence involved in explaining the SN1987A constraint certainly makes such a picture improbable - but it is still intrinsically possible. The lightlike model is appealing in that it does not violate Lorentz symmetry in particle interactions, although one would expect Hughes-Drever tests to turn up a violation eventually. Other evasions of the CG constraints are also possible; perhaps, e.g., the neutrino takes a 'short cut' through extra dimensions or suffers anomalous acceleration in matter. Irrespective of the OPERA result, Lorentz-violating interactions remain possible, and ongoing experimental investigation of such possibilities should continue.

  10. Carbon emission from global hydroelectric reservoirs revisited.

    Science.gov (United States)

    Li, Siyue; Zhang, Quanfa

    2014-12-01

    Substantial greenhouse gas (GHG) emissions from hydropower reservoirs have been of great concerns recently, yet the significant carbon emitters of drawdown area and reservoir downstream (including spillways and turbines as well as river reaches below dams) have not been included in global carbon budget. Here, we revisit GHG emission from hydropower reservoirs by considering reservoir surface area, drawdown zone and reservoir downstream. Our estimates demonstrate around 301.3 Tg carbon dioxide (CO2)/year and 18.7 Tg methane (CH4)/year from global hydroelectric reservoirs, which are much higher than recent observations. The sum of drawdown and downstream emission, which is generally overlooked, represents 42 % CO2 and 67 % CH4 of the total emissions from hydropower reservoirs. Accordingly, the global average emissions from hydropower are estimated to be 92 g CO2/kWh and 5.7 g CH4/kWh. Nonetheless, global hydroelectricity could currently reduce approximate 2,351 Tg CO2eq/year with respect to fuel fossil plant alternative. The new findings show a substantial revision of carbon emission from the global hydropower reservoirs.

  11. Meta-analysis in clinical trials revisited.

    Science.gov (United States)

    DerSimonian, Rebecca; Laird, Nan

    2015-11-01

    In this paper, we revisit a 1986 article we published in this Journal, Meta-Analysis in Clinical Trials, where we introduced a random-effects model to summarize the evidence about treatment efficacy from a number of related clinical trials. Because of its simplicity and ease of implementation, our approach has been widely used (with more than 12,000 citations to date) and the "DerSimonian and Laird method" is now often referred to as the 'standard approach' or a 'popular' method for meta-analysis in medical and clinical research. The method is especially useful for providing an overall effect estimate and for characterizing the heterogeneity of effects across a series of studies. Here, we review the background that led to the original 1986 article, briefly describe the random-effects approach for meta-analysis, explore its use in various settings and trends over time and recommend a refinement to the method using a robust variance estimator for testing overall effect. We conclude with a discussion of repurposing the method for Big Data meta-analysis and Genome Wide Association Studies for studying the importance of genetic variants in complex diseases. Published by Elsevier Inc.

  12. Critical boundary sine-Gordon revisited

    International Nuclear Information System (INIS)

    Hasselfield, M.; Lee, Taejin; Semenoff, G.W.; Stamp, P.C.E.

    2006-01-01

    We revisit the exact solution of the two space-time dimensional quantum field theory of a free massless boson with a periodic boundary interaction and self-dual period. We analyze the model by using a mapping to free fermions with a boundary mass term originally suggested in Ref. [J. Polchinski, L. Thorlacius, Phys. Rev. D 50 (1994) 622]. We find that the entire SL (2, C) family of boundary states of a single boson are boundary sine-Gordon states and we derive a simple explicit expression for the boundary state in fermion variables and as a function of sine-Gordon coupling constants. We use this expression to compute the partition function. We observe that the solution of the model has a strong-weak coupling generalization of T-duality. We then examine a class of recently discovered conformal boundary states for compact bosons with radii which are rational numbers times the self-dual radius. These have simple expression in fermion variables. We postulate sine-Gordon-like field theories with discrete gauge symmetries for which they are the appropriate boundary states

  13. The drive revisited: Mastery and satisfaction.

    Science.gov (United States)

    Denis, Paul

    2016-06-01

    Starting from the theory of the libido and the notions of the experience of satisfaction and the drive for mastery introduced by Freud, the author revisits the notion of the drive by proposing the following model: the drive takes shape in the combination of two currents of libidinal cathexis, one which takes the paths of the 'apparatus for obtaining mastery' (the sense-organs, motricity, etc.) and strives to appropriate the object, and the other which cathects the erotogenic zones and the experience of satisfaction that is experienced through stimulation in contact with the object. The result of this combination of cathexes constitutes a 'representation', the subsequent evocation of which makes it possible to tolerate for a certain period of time the absence of a satisfying object. On the basis of this conception, the author distinguishes the representations proper, vehicles of satisfaction, from imagos and traumatic images which give rise to excitation that does not link up with the paths taken by the drives. This model makes it possible to conciliate the points of view of the advocates of 'object-seeking' and of those who give precedence to the search for pleasure, and, further, to renew our understanding of object-relations, which can then be approached from the angle of their relations to infantile sexuality. Destructiveness is considered in terms of "mastery madness" and not in terms of the late Freudian hypothesis of the death drive. Copyright © 2015 Institute of Psychoanalysis.

  14. Revisiting the argument from fetal potential

    Directory of Open Access Journals (Sweden)

    Manninen Bertha

    2007-05-01

    Full Text Available Abstract One of the most famous, and most derided, arguments against the morality of abortion is the argument from potential, which maintains that the fetus' potential to become a person and enjoy the valuable life common to persons, entails that its destruction is prima facie morally impermissible. In this paper, I will revisit and offer a defense of the argument from potential. First, I will criticize the classical arguments proffered against the importance of fetal potential, specifically the arguments put forth by philosophers Peter Singer and David Boonin, by carefully unpacking the claims made in these arguments and illustrating why they are flawed. Secondly, I will maintain that fetal potential is morally relevant when it comes to the morality of abortion, but that it must be accorded a proper place in the argument. This proper place, however, cannot be found until we first answer a very important and complex question: we must first address the issue of personal identity, and when the fetus becomes the type of being who is relevantly identical to a future person. I will illustrate why the question of fetal potential can only be meaningfully addressed after we have first answered the question of personal identity and how it relates to the human fetus.

  15. THE CONCEPT OF REFERENCE CONDITION, REVISITED ...

    Science.gov (United States)

    Ecological assessments of aquatic ecosystems depend on the ability to compare current conditions against some expectation of how they could be in the absence of significant human disturbance. The concept of a ‘‘reference condition’’ is often used to describe the standard or benchmark against which current condition is compared. If assessments are to be conducted consistently, then a common understanding of the definitions and complications of reference condition is necessary. A 2006 paper (Stoddard et al., 2006, Ecological Applications 16:1267-1276) made an early attempt at codifying the reference condition concept; in this presentation we will revisit the points raised in that paper (and others) and examine how our thinking has changed in a little over 10 years.Among the issues to be discussed: (1) the “moving target” created when reference site data are used to set thresholds in large scale assessments; (2) natural vs. human disturbance and their effects on reference site distributions; (3) circularity and the use of biological data to assist in reference site identification; (4) using site-scale (in-stream or in-lake) measurements vs. landscape-level human activity to identify reference conditions. Ecological assessments of aquatic ecosystems depend on the ability to compare current conditions against some expectation of how they could be in the absence of significant human disturbance. The concept of a ‘‘reference condition’’ is often use

  16. The Super-GUT CMSSM Revisited

    CERN Document Server

    Ellis, John

    2016-01-01

    We revisit minimal supersymmetric SU(5) grand unification (GUT) models in which the soft supersymmetry-breaking parameters of the minimal supersymmetric Standard Model (MSSM) are universal at some input scale, $M_{in}$, above the supersymmetric gauge coupling unification scale, $M_{GUT}$. As in the constrained MSSM (CMSSM), we assume that the scalar masses and gaugino masses have common values, $m_0$ and $m_{1/2}$ respectively, at $M_{in}$, as do the trilinear soft supersymmetry-breaking parameters $A_0$. Going beyond previous studies of such a super-GUT CMSSM scenario, we explore the constraints imposed by the lower limit on the proton lifetime and the LHC measurement of the Higgs mass, $m_h$. We find regions of $m_0$, $m_{1/2}$, $A_0$ and the parameters of the SU(5) superpotential that are compatible with these and other phenomenological constraints such as the density of cold dark matter, which we assume to be provided by the lightest neutralino. Typically, these allowed regions appear for $m_0$ and $m_{1/...

  17. Searle's"Dualism Revisited"

    Energy Technology Data Exchange (ETDEWEB)

    P., Henry

    2008-11-20

    A recent article in which John Searle claims to refute dualism is examined from a scientific perspective. John Searle begins his recent article 'Dualism Revisited' by stating his belief that the philosophical problem of consciousness has a scientific solution. He then claims to refute dualism. It is therefore appropriate to examine his arguments against dualism from a scientific perspective. Scientific physical theories contain two kinds of descriptions: (1) Descriptions of our empirical findings, expressed in an every-day language that allows us communicate to each other our sensory experiences pertaining to what we have done and what we have learned; and (2) Descriptions of a theoretical model, expressed in a mathematical language that allows us to communicate to each other certain ideas that exist in our mathematical imaginations, and that are believed to represent, within our streams of consciousness, certain aspects of reality that we deem to exist independently of their being perceived by any human observer. These two parts of our scientific description correspond to the two aspects of our general contemporary dualistic understanding of the total reality in which we are imbedded, namely the empirical-mental aspect and the theoretical-physical aspect. The duality question is whether this general dualistic understanding of ourselves should be regarded as false in some important philosophical or scientific sense.

  18. Early-Transition Output Decline Revisited

    Directory of Open Access Journals (Sweden)

    Crt Kostevc

    2016-05-01

    Full Text Available In this paper we revisit the issue of aggregate output decline that took place in the early transition period. We propose an alternative explanation of output decline that is applicable to Central- and Eastern-European countries. In the first part of the paper we develop a simple dynamic general equilibrium model that builds on work by Gomulka and Lane (2001. In particular, we consider price liberalization, interpreted as elimination of distortionary taxation, as a trigger of the output decline. We show that price liberalization in interaction with heterogeneous adjustment costs and non-employment benefits lead to aggregate output decline and surge in wage inequality. While these patterns are consistent with actual dynamics in CEE countries, this model cannot generate output decline in all sectors. Instead sectors that were initially taxed even exhibit output growth. Thus, in the second part we consider an alternative general equilibrium model with only one production sector and two types of labor and distortion in a form of wage compression during the socialist era. The trigger for labor mobility and consequently output decline is wage liberalization. Assuming heterogeneity of workers in terms of adjustment costs and non-employment benefits can explain output decline in all industries.

  19. Post-inflationary gravitino production revisited

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, John [Theoretical Particle Physics and Cosmology Group, Department of Physics, King' s College London, London WC2R 2LS (United Kingdom); Garcia, Marcos A.G.; Olive, Keith A. [William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Nanopoulos, Dimitri V. [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Peloso, Marco, E-mail: john.ellis@cern.ch, E-mail: garciagarcia@physics.umn.edu, E-mail: dimitri@physics.tamu.edu, E-mail: olive@physics.umn.edu, E-mail: peloso@physics.umn.edu [School of Physics and Astronomy and Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

    2016-03-01

    We revisit gravitino production following inflation. As a first step, we review the standard calculation of gravitino production in the thermal plasma formed at the end of post-inflationary reheating when the inflaton has completely decayed. Next we consider gravitino production prior to the completion of reheating, assuming that the inflaton decay products thermalize instantaneously while they are still dilute. We then argue that instantaneous thermalization is in general a good approximation, and also show that the contribution of non-thermal gravitino production via the collisions of inflaton decay products prior to thermalization is relatively small. Our final estimate of the gravitino-to-entropy ratio is approximated well by a standard calculation of gravitino production in the post-inflationary thermal plasma assuming total instantaneous decay and thermalization at a time t ≅ 1.2/Γ{sub φ}. Finally, in light of our calculations, we consider potential implications of upper limits on the gravitino abundance for models of inflation, with particular attention to scenarios for inflaton decays in supersymmetric Starobinsky-like models.

  20. Pipe failure probability - the Thomas paper revisited

    International Nuclear Information System (INIS)

    Lydell, B.O.Y.

    2000-01-01

    Almost twenty years ago, in Volume 2 of Reliability Engineering (the predecessor of Reliability Engineering and System Safety), a paper by H. M. Thomas of Rolls Royce and Associates Ltd. presented a generalized approach to the estimation of piping and vessel failure probability. The 'Thomas-approach' used insights from actual failure statistics to calculate the probability of leakage and conditional probability of rupture given leakage. It was intended for practitioners without access to data on the service experience with piping and piping system components. This article revisits the Thomas paper by drawing on insights from development of a new database on piping failures in commercial nuclear power plants worldwide (SKI-PIPE). Partially sponsored by the Swedish Nuclear Power Inspectorate (SKI), the R and D leading up to this note was performed during 1994-1999. Motivated by data requirements of reliability analysis and probabilistic safety assessment (PSA), the new database supports statistical analysis of piping failure data. Against the background of this database development program, the article reviews the applicability of the 'Thomas approach' in applied risk and reliability analysis. It addresses the question whether a new and expanded database on the service experience with piping systems would alter the original piping reliability correlation as suggested by H. M. Thomas

  1. Revisit to diffraction anomalous fine structure

    International Nuclear Information System (INIS)

    Kawaguchi, T.; Fukuda, K.; Tokuda, K.; Shimada, K.; Ichitsubo, T.; Oishi, M.; Mizuki, J.; Matsubara, E.

    2014-01-01

    The diffraction anomalous fine structure method has been revisited by applying this measurement technique to polycrystalline samples and using an analytical method with the logarithmic dispersion relation. The diffraction anomalous fine structure (DAFS) method that is a spectroscopic analysis combined with resonant X-ray diffraction enables the determination of the valence state and local structure of a selected element at a specific crystalline site and/or phase. This method has been improved by using a polycrystalline sample, channel-cut monochromator optics with an undulator synchrotron radiation source, an area detector and direct determination of resonant terms with a logarithmic dispersion relation. This study makes the DAFS method more convenient and saves a large amount of measurement time in comparison with the conventional DAFS method with a single crystal. The improved DAFS method has been applied to some model samples, Ni foil and Fe 3 O 4 powder, to demonstrate the validity of the measurement and the analysis of the present DAFS method

  2. Revisiting the Survival Mnemonic Effect in Children

    Directory of Open Access Journals (Sweden)

    Josefa N. S. Pand Eirada

    2014-04-01

    Full Text Available The survival processing paradigm is designed to explore the adaptive nature of memory functioning. The mnemonic advantage of processing information in fitness-relevant contexts, as has been demonstrated using this paradigm, is now well established, particularly in young adults; this phenomenon is often referred to as the “survival processing effect.” In the current experiment, we revisited the investigation of this effect in children and tested it in a new cultural group, using a procedure that differs from the existing studies with children. A group of 40 Portuguese children rated the relevance of unrelated words to a survival and a new moving scenario. This encoding task was followed by a surprise free-recall task. Akin to what is typically found, survival processing produced better memory performance than the control condition (moving. These data put on firmer ground the idea that a mnemonic tuning to fitness-relevant encodings is present early in development. The theoretical importance of this result to the adaptive memory literature is discussed, as well as potential practical implications of this kind of approach to the study of memory in children.

  3. Islanded operation of distributed networks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This report summarises the findings of a study to investigate the regulatory, commercial and technical risks and benefits associated with the operation of distributed generation to power an islanded section of distributed network. A review of published literature was carried out, and UK generators were identified who could operate as part of an island network under the existing technical, regulatory, and safety framework. Agreement on case studies for consideration with distributed network operators (DNOs) is discussed as well as the quantification of the risks, benefits and costs of islanding, and the production of a case implementation plan for each case study. Technical issues associated with operating sections of network in islanded mode are described, and impacts of islanding on trading and settlement, and technical and commercial modelling are explored.

  4. Islanded operation of distributed networks

    International Nuclear Information System (INIS)

    2005-01-01

    This report summarises the findings of a study to investigate the regulatory, commercial and technical risks and benefits associated with the operation of distributed generation to power an islanded section of distributed network. A review of published literature was carried out, and UK generators were identified who could operate as part of an island network under the existing technical, regulatory, and safety framework. Agreement on case studies for consideration with distributed network operators (DNOs) is discussed as well as the quantification of the risks, benefits and costs of islanding, and the production of a case implementation plan for each case study. Technical issues associated with operating sections of network in islanded mode are described, and impacts of islanding on trading and settlement, and technical and commercial modelling are explored

  5. Molecular Phylogeny and Historical Biogeography of the Neotropical Swarm-Founding Social Wasp Genus Synoeca (Hymenoptera: Vespidae)

    Science.gov (United States)

    Menezes, Rodolpho Santos Telles; Brady, Seán Gary; Carvalho, Antônio Freire; Del Lama, Marco Antonio; Costa, Marco Antônio

    2015-01-01

    The Neotropical Region harbors high biodiversity and many studies on mammals, reptiles, amphibians and avifauna have investigated the causes for this pattern. However, there is a paucity of such studies that focus on Neotropical insect groups. Synoeca de Saussure, 1852 is a Neotropical swarm-founding social wasp genus with five described species that is broadly and conspicuously distributed throughout the Neotropics. Here, we infer the phylogenetic relationships, diversification times, and historical biogeography of Synoeca species. We also investigate samples of the disjoint populations of S. septentrionalis that occur in both northwestern parts of South America through Central American and the Brazilian Atlantic rainforests. Our results showed that the interspecific relationships for Synoeca could be described as follows: (S. chalibea + S. virginea) + (S. cyanea + (S. septentrionalis/S. surinama)). Notably, samples of S. septentrionalis and S. surinama collected in the Atlantic Forest were interrelated and may be the result of incomplete lineage sorting and/or mitochondrial introgression among them. Our Bayesian divergence dating analysis revealed recent Plio-Pleistocene diversification in Synoeca. Moreover, our biogeographical analysis suggested an Amazonian origin of Synoeca, with three main dispersal events subsequently occurring during the Plio-Pleistocene. PMID:25738705

  6. Diversification of the cold-adapted butterfly genus Oeneis related to Holarctic biogeography and climatic niche shifts.

    Science.gov (United States)

    Kleckova, I; Cesanek, M; Fric, Z; Pellissier, L

    2015-11-01

    Both geographical and ecological speciation interact during the evolution of a clade, but the relative contribution of these processes is rarely assessed for cold-dwelling biota. Here, we investigate the role of biogeography and the evolution of ecological traits on the diversification of the Holarctic arcto-alpine butterfly genus Oeneis (Lepidoptera: Satyrinae). We reconstructed the molecular phylogeny of the genus based on one mitochondrial (COI) and three nuclear (GAPDH, RpS5, wingless) genes. We inferred the biogeographical scenario and the ancestral state reconstructions of climatic and habitat requirements. Within the genus, we detected five main species groups corresponding to the taxonomic division and further paraphyletic position of Neominois (syn. n.). Next, we transferred O. aktashi from the hora to the polixenes species group on the bases of molecular relationships. We found that the genus originated in the dry grasslands of the mountains of Central Asia and dispersed over the Beringian Land Bridges to North America several times independently. Holarctic mountains, in particular the Asian Altai Mts. and Sayan Mts., host the oldest lineages and most of the species diversity. Arctic species are more recent, with Pliocene or Pleistocene origin. We detected a strong phylogenetic signal for the climatic niche, where one lineage diversified towards colder conditions. Altogether, our results indicate that both dispersal across geographical areas and occupation of distinct climatic niches promoted the diversification of the Oeneis genus. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Drivers shaping the diversity and biogeography of total and active bacterial communities in the South China Sea

    Science.gov (United States)

    Zhang, Yao; Zhao, Zihao; Dai, Minhan; Jiao, Nianzhi; Herndl, Gerhard J

    2014-01-01

    To test the hypothesis that different drivers shape the diversity and biogeography of the total and active bacterial community, we examined the bacterial community composition along two transects, one from the inner Pearl River estuary to the open waters of the South China Sea (SCS) and the other from the Luzon Strait to the SCS basin, using 454 pyrosequencing of the 16S rRNA and 16S rRNA gene (V1-3 regions) and thereby characterizing the active and total bacterial community, respectively. The diversity and biogeographic patterns differed substantially between the active and total bacterial communities. Although the composition of both the total and active bacterial community was strongly correlated with environmental factors and weakly correlated with geographic distance, the active bacterial community displayed higher environmental sensitivity than the total community and particularly a greater distance effect largely caused by the active assemblage from deep waters. The 16S rRNA vs. rDNA relationships indicated that the active bacteria were low in relative abundance in the SCS. This might be due to a high competition between active bacterial taxa as indicated by our community network models. Based on these analyses, we speculate that high competition could cause some dispersal limitation of the active bacterial community resulting in a distinct distance-decay relationship. Altogether, our results indicated that the biogeographic distribution of bacteria in the SCS is the result of both environmental control and distance decay. PMID:24684298

  8. Molecular phylogeny and historical biogeography of the neotropical swarm-founding social wasp genus Synoeca (Hymenoptera: Vespidae.

    Directory of Open Access Journals (Sweden)

    Rodolpho Santos Telles Menezes

    Full Text Available The Neotropical Region harbors high biodiversity and many studies on mammals, reptiles, amphibians and avifauna have investigated the causes for this pattern. However, there is a paucity of such studies that focus on Neotropical insect groups. Synoeca de Saussure, 1852 is a Neotropical swarm-founding social wasp genus with five described species that is broadly and conspicuously distributed throughout the Neotropics. Here, we infer the phylogenetic relationships, diversification times, and historical biogeography of Synoeca species. We also investigate samples of the disjoint populations of S. septentrionalis that occur in both northwestern parts of South America through Central American and the Brazilian Atlantic rainforests. Our results showed that the interspecific relationships for Synoeca could be described as follows: (S. chalibea + S. virginea + (S. cyanea + (S. septentrionalis/S. surinama. Notably, samples of S. septentrionalis and S. surinama collected in the Atlantic Forest were interrelated and may be the result of incomplete lineage sorting and/or mitochondrial introgression among them. Our Bayesian divergence dating analysis revealed recent Plio-Pleistocene diversification in Synoeca. Moreover, our biogeographical analysis suggested an Amazonian origin of Synoeca, with three main dispersal events subsequently occurring during the Plio-Pleistocene.

  9. An analysis of dinosaurian biogeography: evidence for the existence of vicariance and dispersal patterns caused by geological events.

    Science.gov (United States)

    Upchurch, Paul; Hunn, Craig A; Norman, David B

    2002-03-22

    As the supercontinent Pangaea fragmented during the Mesozoic era, dinosaur faunas were divided into isolated populations living on separate continents. It has been predicted, therefore, that dinosaur distributions should display a branching ('vicariance') pattern that corresponds with the sequence and timing of continental break-up. Several recent studies, however, minimize the importance of plate tectonics and instead suggest that dispersal and regional extinction were the main controls on dinosaur biogeography. Here, in order to test the vicariance hypothesis, we apply a cladistic biogeographical method to a large dataset on dinosaur relationships and distributions. We also introduce a methodological refinement termed 'time-slicing', which is shown to be a key step in the detection of ancient biogeographical patterns. These analyses reveal biogeographical patterns that closely correlate with palaeogeography. The results provide the first statistically robust evidence that, from Middle Jurassic to mid-Cretaceous times, tectonic events had a major role in determining where and when particular dinosaur groups flourished. The fact that evolutionary trees for extinct organisms preserve such distribution patterns opens up a new and fruitful direction for palaeobiogeographical research.

  10. Phylogeny, historical biogeography and characters evolution of the drought resistant fern Pyrrosia Mirbel (Polypodiaceae) inferred from plastid and nuclear markers.

    Science.gov (United States)

    Wei, Xueping; Qi, Yaodong; Zhang, Xianchun; Luo, Li; Shang, Hui; Wei, Ran; Liu, Haitao; Zhang, Bengang

    2017-10-06

    Pyrrosia s.l. comprises ca. 60 species with a disjunct Africa/Asia and Australia distribution. The infrageneric classification of Pyrrosia s.l. is controversial based on the phylogenetic analyses of chloroplast markers and morphology. Based on the expanded taxon sampling of Pyrrosia s.l. (51 species), we investigated its phylogeny, biogeography, character evolution and environmental adaptation by employing five chloroplastid markers (rbcL, matK, psbA-trnH, and rps4 + rps4-trnS) and one single (low)-copy nuclear gene, LEAFY. Pyrrosia s.l. was divided into six major clades and eight subclades. Reticulate evolution was revealed both among clades and among species in Pyrrosia s.l. Ancestral character state optimization revealed high levels of homoplastic evolution of the diagnostic characters in Pyrrosia s.l., while the crassulacean acid metabolism pathway seems to have an independent origin. Molecular dating and biogeographic diversification analyses suggested that Pyrrosia s.l. originated no later than the Oligocene and the main clades diversified during the Oligocene and Miocene, with southern Asia, the Indo-China Peninsula and southwestern and southern China as the most likely ancestral areas. Transoceanic long-distance dispersal, rather than vicariance, contributed to the intercontinental disjunction. Diversification scenarios of Pyrrosia s.l. under geological movements and climate fluctuation are also discussed.

  11. Biogeography-based combinatorial strategy for efficient autonomous underwater vehicle motion planning and task-time management

    Science.gov (United States)

    Zadeh, S. M.; Powers, D. M. W.; Sammut, K.; Yazdani, A. M.

    2016-12-01

    Autonomous Underwater Vehicles (AUVs) are capable of spending long periods of time for carrying out various underwater missions and marine tasks. In this paper, a novel conflict-free motion planning framework is introduced to enhance underwater vehicle's mission performance by completing maximum number of highest priority tasks in a limited time through a large scale waypoint cluttered operating field, and ensuring safe deployment during the mission. The proposed combinatorial route-path planner model takes the advantages of the Biogeography-Based Optimization (BBO) algorithm toward satisfying objectives of both higher-lower level motion planners and guarantees maximization of the mission productivity for a single vehicle operation. The performance of the model is investigated under different scenarios including the particular cost constraints in time-varying operating fields. To show the reliability of the proposed model, performance of each motion planner assessed separately and then statistical analysis is undertaken to evaluate the total performance of the entire model. The simulation results indicate the stability of the contributed model and its feasible application for real experiments.

  12. The historical biogeography of Pteroglossus aracaris (Aves, Piciformes, Ramphastidae based on Bayesian analysis of mitochondrial DNA sequences

    Directory of Open Access Journals (Sweden)

    Sérgio L. Pereira

    2008-01-01

    Full Text Available Most Neotropical birds, including Pteroglossus aracaris, do not have an adequate fossil record to be used as time constraints in molecular dating. Hence, the evolutionary timeframe of the avian biota can only be inferred using alternative time constraints. We applied a Bayesian relaxed clock approach to propose an alternative interpretation for the historical biogeography of Pteroglossus based on mitochondrial DNA sequences, using different combinations of outgroups and time constraints obtained from outgroup fossils, vicariant barriers and molecular time estimates. The results indicated that outgroup choice has little effect on the Bayesian posterior distribution of divergence times within Pteroglossus , that geological and molecular time constraints seem equally suitable to estimate the Bayesian posterior distribution of divergence times for Pteroglossus , and that the fossil record alone overestimates divergence times within the fossil-lacking ingroup. The Bayesian estimates of divergence times suggest that the radiation of Pteroglossus occurred from the Late Miocene to the Pliocene (three times older than estimated by the “standard” mitochondrial rate of 2% sequence divergence per million years, likely triggered by Andean uplift, multiple episodes of marine transgressions in South America, and formation of present-day river basins. The time estimates are in agreement with other Neotropical taxa with similar geographic distributions.

  13. Amplicon-Based Pyrosequencing Reveals High Diversity of Protistan Parasites in Ships' Ballast Water: Implications for Biogeography and Infectious Diseases.

    Science.gov (United States)

    Pagenkopp Lohan, K M; Fleischer, R C; Carney, K J; Holzer, K K; Ruiz, G M

    2016-04-01

    Ships' ballast water (BW) commonly moves macroorganisms and microorganisms across the world's oceans and along coasts; however, the majority of these microbial transfers have gone undetected. We applied high-throughput sequencing methods to identify microbial eukaryotes, specifically emphasizing the protistan parasites, in ships' BW collected from vessels calling to the Chesapeake Bay (Virginia and Maryland, USA) from European and Eastern Canadian ports. We utilized tagged-amplicon 454 pyrosequencing with two general primer sets, amplifying either the V4 or V9 domain of the small subunit (SSU) of the ribosomal RNA (rRNA) gene complex, from total DNA extracted from water samples collected from the ballast tanks of bulk cargo vessels. We detected a diverse group of protistan taxa, with some known to contain important parasites in marine systems, including Apicomplexa (unidentified apicomplexans, unidentified gregarines, Cryptosporidium spp.), Dinophyta (Blastodinium spp., Euduboscquella sp., unidentified syndinids, Karlodinium spp., Syndinium spp.), Perkinsea (Parvilucifera sp.), Opisthokonta (Ichthyosporea sp., Pseudoperkinsidae, unidentified ichthyosporeans), and Stramenopiles (Labyrinthulomycetes). Further characterization of groups with parasitic taxa, consisting of phylogenetic analyses for four taxa (Cryptosporidium spp., Parvilucifera spp., Labyrinthulomycetes, and Ichthyosporea), revealed that sequences were obtained from both known and novel lineages. This study demonstrates that high-throughput sequencing is a viable and sensitive method for detecting parasitic protists when present and transported in the ballast water of ships. These data also underscore the potential importance of human-aided dispersal in the biogeography of these microbes and emerging diseases in the world's oceans.

  14. Divergence time, historical biogeography and evolutionary rate estimation of the order Bangiales (Rhodophyta) inferred from multilocus data

    Science.gov (United States)

    Xu, Kuipeng; Tang, Xianghai; Wang, Lu; Yu, Xinzi; Sun, Peipei; Mao, Yunxiang

    2017-08-01

    Bangiales is the only order of the Bangiophyceae and has been suggested to be monophyletic. This order contains approximately 190 species and is distributed worldwide. Previous molecular studies have produced robust phylogenies among the red algae, but the divergence times, historical biogeography and evolutionary rates of Bangiales have rarely been studied. Phylogenetic relationships within the Bangiales were examined using the concatenated gene sets from all available organellar genomes. This analysis has revealed the topology ((( Bangia, Porphyra ) Pyropia ) Wildemania ). Molecular dating indicates that Bangiales diversified approximately 246.40 million years ago (95% highest posterior density (HPD)= 194.78u2013318.24 Ma, posterior probability (PP)=0.99) in the Late Permian and Early Triassic, and that the ancestral species most likely originated from eastern Gondwanaland (currently New Zealand and Australia) and subsequently began to spread and evolve worldwide. Based on pairwise comparisons, we found a slower rate of nucleotide substitutions and lower rates of diversification in Bangiales relative to Florideophyceae. Compared with Viridiplantae (green algae and land plants), the evolutionary rates of Bangiales and other Rhodophyte groups were found to be dramatically faster, by more than 3-fold for plastid genome (ptDNA) and 15-fold for mitochondrial genome (mtDNA). In addition, an average 2.5-fold lower dN/dS was found for the algae than for the land plants, which indicates purifying selection of the algae.

  15. The tempo and mode of New World monkey evolution and biogeography in the context of phylogenomic analysis.

    Science.gov (United States)

    Jameson Kiesling, Natalie M; Yi, Soojin V; Xu, Ke; Gianluca Sperone, F; Wildman, Derek E

    2015-01-01

    The development and evolution of organisms is heavily influenced by their environment. Thus, understanding the historical biogeography of taxa can provide insights into their evolutionary history, adaptations and trade-offs realized throughout time. In the present study we have taken a phylogenomic approach to infer New World monkey phylogeny, upon which we have reconstructed the biogeographic history of extant platyrrhines. In order to generate sufficient phylogenetic signal within the New World monkey clade, we carried out a large-scale phylogenetic analysis of approximately 40 kb of non-genic genomic DNA sequence in a 36 species subset of extant New World monkeys. Maximum parsimony, maximum likelihood and Bayesian inference analysis all converged on a single optimal tree topology. Divergence dating and biogeographic analysis reconstruct the timing and geographic location of divergence events. The ancestral area reconstruction describes the geographic locations of the last common ancestor of extant platyrrhines and provides insight into key biogeographic events occurring during platyrrhine diversification. Through these analyses we conclude that the diversification of the platyrrhines took place concurrently with the establishment and diversification of the Amazon rainforest. This suggests that an expanding rainforest environment rather than geographic isolation drove platyrrhine diversification. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Biogeography and taxonomy of racket-tail hummingbirds (Aves: Trochilidae: Ocreatus): evidence for species delimitation from morphology and display behavior.

    Science.gov (United States)

    Schuchmann, Karl-L; Weller, André-A; Jürgens, Dietmar

    2016-11-27

    We analyzed geographic variation, biogeography, and intrageneric relationships of racket-tail hummingbirds Ocreatus (Aves, Trochilidae). Presently, the genus is usually considered monospecific, with O. underwoodii including eight subspecies (polystictus, discifer, underwoodii, incommodus, melanantherus, peruanus, annae, addae), although up to three species have been recognized by some authors. In order to evaluate the current taxonomy we studied geographic variation in coloration, mensural characters, and behavioral data of all Ocreatus taxa. We briefly review the taxonomic history of the genus. Applying the Biological Species Concept, species delimitation was based on a qualitative-quantitative criteria analysis including an evaluation of character states. Our results indicate that the genus should be considered a superspecies with four species, the monotypic Ocreatus addae, O. annae, and O. peruanus, and the polytypic O. underwoodii (including the subspecies underwoodii, discifer, incommodus, melanantherus, polystictus). In this taxonomic treatment, O. annae becomes an endemic species to Peru and O. addae is endemic to Bolivia. We recommend additional sampling of distributional, ethological, and molecular data for an improved resolution of the evolutionary history of Ocreatus.

  17. Biogeography and taxonomy of extinct and endangered monk seals illuminated by ancient DNA and skull morphology

    Directory of Open Access Journals (Sweden)

    Dirk-Martin Scheel

    2014-05-01

    Full Text Available Extinctions and declines of large marine vertebrates have major ecological impacts and are of critical concern in marine environments. The Caribbean monk seal, Monachus tropicalis, last definitively reported in 1952, was one of the few marine mammal species to become extinct in historical times. Despite its importance for understanding the evolutionary biogeography of southern phocids, the relationships of M.tropicalis to the two living species of critically endangered monk seals have not been resolved. In this study we present the first molecular data for M. tropicalis, derived from museum skins. Phylogenetic analysis of cytochrome b sequences indicates that M. tropicalis was more closely related to the Hawaiian rather than the Mediterranean monk seal. Divergence time estimation implicates the formation of the Panamanian Isthmus in the speciation of Caribbean and Hawaiian monk seals. Molecular, morphological and temporal divergence between the Mediterranean and “New World monk seals” (Hawaiian and Caribbean is profound, equivalent to or greater than between sister genera of phocids. As a result, we classify the Caribbean and Hawaiian monk seals together in a newly erected genus, Neomonachus. The two genera of extant monk seals (Monachus and Neomonachus represent old evolutionary lineages each represented by a single critically endangered species, both warranting continuing and concerted conservation attention and investment if they are to avoid the fate of their Caribbean relative.

  18. A Mosaic of Geothermal and Marine Features Shapes Microbial Community Structure on Deception Island Volcano, Antarctica

    Directory of Open Access Journals (Sweden)

    Amanda G. Bendia

    2018-05-01

    Full Text Available Active volcanoes in Antarctica contrast with their predominantly cold surroundings, resulting in environmental conditions capable of selecting for versatile and extremely diverse microbial communities. This is especially true on Deception Island, where geothermal, marine, and polar environments combine to create an extraordinary range of environmental conditions. Our main goal in this study was to understand how microbial community structure is shaped by gradients of temperature, salinity, and geochemistry in polar marine volcanoes. Thereby, we collected surface sediment samples associated with fumaroles and glaciers at two sites on Deception, with temperatures ranging from 0 to 98°C. Sequencing of the 16S rRNA gene was performed to assess the composition and diversity of Bacteria and Archaea. Our results revealed that Deception harbors a combination of taxonomic groups commonly found both in cold and geothermal environments of continental Antarctica, and also groups normally identified at deep and shallow-sea hydrothermal vents, such as hyperthermophilic archaea. We observed a clear separation in microbial community structure across environmental gradients, suggesting that microbial community structure is strongly niche driven on Deception. Bacterial community structure was significantly associated with temperature, pH, salinity, and chemical composition; in contrast, archaeal community structure was strongly associated only with temperature. Our work suggests that Deception represents a peculiar “open-air” laboratory to elucidate central questions regarding molecular adaptability, microbial evolution, and biogeography of extremophiles in polar regions.

  19. Arctic biogeography: The paradox of the marine benthic fauna and flora.

    Science.gov (United States)

    Dunton, K

    1992-06-01

    The marine benthic fauna and flora that inhabit the shallow arctic sublittoral zone comprise a relatively young marine assemblage characterized by species of either Pacific or Atlantic affinity and notably few endemics. The young character of nearshore arctic communities, as well as their biogeographical composition, is largely a product of the Pleistocene glaciation. However, analysis of more recent collections and comparison between the origins of the benthic fauna and flora present some interesting paradoxes to biogeographers. One enigma is the low frequency of algal species with Pacific affinities in the Arctic, especially in the Chukchi, Beaufort and East Siberian Seas of the Eastern Arctic, which receive direct inputs of northward-flowing Pacific waters. In contrast, animal species with Pacific affinities are found throughout the nearshore regions of the Arctic, reaching their highest frequency in the marginal seas between the New Siberian Islands and the Canadian Archipelago. Organization of published and unpublished data, additional field collections, and the use of cladistics and molecular DNA techniques by systematists are a high priority for future research in reconstructing the evolution of the arctic biotic assemblage. Copyright © 1992. Published by Elsevier Ltd.

  20. Biogeography of the Malagasy Celastraceae: Multiple independent origins followed by widespread dispersal of genera from Madagascar.

    Science.gov (United States)

    Bacon, Christine D; Simmons, Mark P; Archer, Robert H; Zhao, Liang-Cheng; Andriantiana, Jacky

    2016-01-01

    Of the 97 currently recognized genera of Celastraceae, 19 are native to Madagascar, including six endemics. In this study we conducted the most thorough phylogenetic analysis of Celastraceae yet completed with respect to both character and taxon sampling, and include representatives of five new endemic genera. Fifty-one new accessions, together with 328 previously used accessions of Celastrales, were sampled for morphological characters, two rDNA gene regions, and two plastid gene regions. The endemic Malagasy genera are resolved in two separate lineages-Xenodrys by itself and all other endemic genera in a clade that also includes four lineages inferred to have dispersed from Madagascar: Brexia madagascariensis (Mascarene Islands, coastal Africa), Elaeodendron (West Indies, Africa to New Caledonia), and Pleurostylia (Africa to New Caledonia). Of the 12 extant Malagasy Celastraceae lineages identified, eight are clearly of African origin. The origins of the remaining four lineages are less clear, but reasonable possibilities include America, Eurasia, Africa, southern India, Malesia, and Australia. Based on 95% credible age intervals from fossil-calibrated molecular dating, all 12 extant Malagasy Celastraceae lineages appear to have arisen following dispersal after the separation of Madagascar from other landmasses within the last 70 million years. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Island in an island – The suggestions for transportation improvement plan for Haidian Island, Haikou, Hainan

    Directory of Open Access Journals (Sweden)

    Sia Rosalind Juo Ling

    2017-01-01

    Full Text Available Haidian Island, which situated at the Northern part of Haikou City of Hainan Province, is an island within a city. Haidian Island is unique in term of it's development which centered around an university, the Hainan University, besides some others important landmarks, such as Haikou city hospital, Baishamen municipal park, Golf Driving Range etc. All commercials, residential, recreational activities etc are planned to serve Hainan University in particular. The study, taking ‘Haidian Island Area Development Control Plan’ as case study, would like to look into the importance of transportation and traffic planning. The study used observation, site investigation and traffic study methods to gather data needed. Firstly the study analyzed the current state of transportation system for Haidian Island in accordance to the Island Development Control plan and Haikou master plan and identified the problems. Then, the study made some recommendations for these problems. The study highlighted the important of non-motorized, cycling and walking as the main transportation system for an education-based island and as supportive to domestic tourism activities found. The transportation planning suggested by the study took ‘green and low-carbon’ approaches considered the role of University as the core activity in the island.

  2. Energy Self-Sufficient Island

    International Nuclear Information System (INIS)

    Bratic, S.; Krajacic, G.; Duic, N.; Cotar, A.; Jardas, D.

    2011-01-01

    In order to analyze energy self-sufficient island, example of a smaller island, connected to the power system of a bigger island with an undersea cable, was taken. Mounting substation 10/0,4 is situated on the island and for the moment it provides enough electricity using the medium voltage line. It is assumed that the island is situated on the north part of the Adriatic Sea. The most important problem that occurs on the island is the population drop that occurs for a significant number of years, therefore, life standard needs to be improved, and economic development needs to be encouraged immediately. Local authorities to stimulate sustainable development on the island through different projects, to breath in a new life to the island, open new jobs and attract new people to come live there. Because of the planned development and increase of the population, energy projects, planned as a support to sustainable development, and later achievement of the energy self-sufficiency, is described in this paper. Therefore, Rewisland methodology appliance is described taking into the account three possible scenarios of energy development. Each scenario is calculated until year 2030. Also, what is taken into the account is 100% usage of renewable sources of energy in 2030. Scenario PTV, PP, EE - This scenario includes installation of solar photovoltaic modules and solar thermal collectors on the buildings roofs, as well as well as implementation of energy efficiency on the island (replacement of the street light bulbs with LED lightning, replacement of the old windows and doors on the houses, as well as the installation of the thermal insulation). Scenario PV island - This scenario, similarly to the previous one, includes installation of solar photovoltaic modules and solar thermal collectors an the residential buildings, as well as the 2 MW photovoltaic power plant and ''Green Hotel'', a building that satisfies all of its energy needs completely from renewable energy sources

  3. Pockets of Participation: Revisiting Child-Centred Participation Research

    Science.gov (United States)

    Franks, Myfanwy

    2011-01-01

    This article revisits the theme of the clash of interests and power relations at work in participatory research which is prescribed from above. It offers a possible route toward solving conflict between adult-led research carried out by young researchers, funding requirements and organisational constraints. The article explores issues of…

  4. Rereading Albert B. Lord's The Singer of Tales . Revisiting the ...

    African Journals Online (AJOL)

    Access to a fresh set of video-recordings of Sesotho praise-poetry made in the year 2000 enabled the author to revisit his adaptation of Albert Lord's definition of the formula as a dynamic compositional device that the oral poet utilizes during delivery. The basic adaptation made in 1983 pertains to heroic praises (dithoko tsa ...

  5. Literary Origins of the Term "School Psychologist" Revisited

    Science.gov (United States)

    Fagan, Thomas K.

    2005-01-01

    Previous research on the literary origins of the term "school psychologist" is revisited, and conclusions are revised in light of new evidence. It appears that the origin of the term in the American literature occurred as early as 1898 in an article by Hugo Munsterberg, predating the usage by Wilhelm Stern in 1911. The early references to the…

  6. The Neutrosophic Logic View to Schrodinger's Cat Paradox, Revisited

    Directory of Open Access Journals (Sweden)

    Florentin Smarandache

    2008-07-01

    Full Text Available The present article discusses Neutrosophic logic view to Schrodinger's cat paradox. We argue that this paradox involves some degree of indeterminacy (unknown which Neutrosophic logic can take into consideration, whereas other methods including Fuzzy logic cannot. To make this proposition clear, we revisit our previous paper by offering an illustration using modified coin tossing problem, known as Parrondo's game.

  7. Revisiting Constructivist Teaching Methods in Ontario Colleges Preparing for Accreditation

    Science.gov (United States)

    Schultz, Rachel A.

    2015-01-01

    At the time of writing, the first community colleges in Ontario were preparing for transition to an accreditation model from an audit system. This paper revisits constructivist literature, arguing that a more pragmatic definition of constructivism effectively blends positivist and interactionist philosophies to achieve both student centred…

  8. High precision mass measurements in Ψ and Υ families revisited

    International Nuclear Information System (INIS)

    Artamonov, A.S.; Baru, S.E.; Blinov, A.E.

    2000-01-01

    High precision mass measurements in Ψ and Υ families performed in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the J/Ψ(1S) and Ψ(2S) mass measurements [ru

  9. Surface tension in soap films: revisiting a classic demonstration

    International Nuclear Information System (INIS)

    Behroozi, F

    2010-01-01

    We revisit a classic demonstration for surface tension in soap films and introduce a more striking variation of it. The demonstration shows how the film, pulling uniformly and normally on a loose string, transforms it into a circular arc under tension. The relationship between the surface tension and the string tension is analysed and presented in a useful graphical form. (letters and comments)

  10. Additively homomorphic encryption with a double decryption mechanism, revisited

    NARCIS (Netherlands)

    Peter, Andreas; Kronberg, M.; Trei, W.; Katzenbeisser, S.

    We revisit the notion of additively homomorphic encryption with a double decryption mechanism (DD-PKE), which allows for additions in the encrypted domain while having a master decryption procedure that can decrypt all properly formed ciphertexts by using a special master secret. This type of

  11. Revisiting Jack Goody to Rethink Determinisms in Literacy Studies

    Science.gov (United States)

    Collin, Ross

    2013-01-01

    This article revisits Goody's arguments about literacy's influence on social arrangements, culture, cognition, economics, and other domains of existence. Whereas some of his arguments tend toward technological determinism (i.e., literacy causes change in the world), other of his arguments construe literacy as a force that shapes and is shaped by…

  12. Surface tension in soap films: revisiting a classic demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Behroozi, F [Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614 (United States)], E-mail: behroozi@uni.edu

    2010-01-15

    We revisit a classic demonstration for surface tension in soap films and introduce a more striking variation of it. The demonstration shows how the film, pulling uniformly and normally on a loose string, transforms it into a circular arc under tension. The relationship between the surface tension and the string tension is analysed and presented in a useful graphical form. (letters and comments)

  13. A control center design revisited: learning from users’ appropriation

    DEFF Research Database (Denmark)

    Souza da Conceição, Carolina; Cordeiro, Cláudia

    2014-01-01

    This paper aims to present the lessons learned during a control center design project by revisiting another control center from the same company designed two and a half years before by the same project team. In light of the experience with the first project and its analysis, the designers and res...

  14. A Feminist Revisit to the First-Year Curriculum.

    Science.gov (United States)

    Bernstein, Anita

    1996-01-01

    A seminar at Chicago-Kent College of Law (Illinois) that reviews six first-year law school courses by focusing on feminist issues in course content and structure is described. The seminar functions as both a review and a shift in perspective. Courses revisited include civil procedure, contracts, criminal law, justice and the legal system,…

  15. Revisiting deforestation in Africa (1990–2010): One more lost ...

    African Journals Online (AJOL)

    This spotlight revisits the dynamics and prognosis outlined in the late 1980's published in Déforestation en Afrique. This book on deforestation in Africa utilized available statistical data from the 1980's and was a pioneering self - styled attempt to provide a holistic viewpoint of the ongoing trends pertaining to deforestation in ...

  16. Moral Judgment Development across Cultures: Revisiting Kohlberg's Universality Claims

    Science.gov (United States)

    Gibbs, John C.; Basinger, Karen S.; Grime, Rebecca L.; Snarey, John R.

    2007-01-01

    This article revisits Kohlberg's cognitive developmental claims that stages of moral judgment, facilitative processes of social perspective-taking, and moral values are commonly identifiable across cultures. Snarey [Snarey, J. (1985). "The cross-cultural universality of social-moral development: A critical review of Kohlbergian research."…

  17. Revisiting the quantum harmonic oscillator via unilateral Fourier transforms

    International Nuclear Information System (INIS)

    Nogueira, Pedro H F; Castro, Antonio S de

    2016-01-01

    The literature on the exponential Fourier approach to the one-dimensional quantum harmonic oscillator problem is revised and criticized. It is shown that the solution of this problem has been built on faulty premises. The problem is revisited via the Fourier sine and cosine transform method and the stationary states are properly determined by requiring definite parity and square-integrable eigenfunctions. (paper)

  18. Transport benchmarks for one-dimensional binary Markovian mixtures revisited

    International Nuclear Information System (INIS)

    Malvagi, F.

    2013-01-01

    The classic benchmarks for transport through a binary Markovian mixture are revisited to look at the probability distribution function of the chosen 'results': reflection, transmission and scalar flux. We argue that the knowledge of the ensemble averaged results is not sufficient for reliable predictions: a measure of the dispersion must also be obtained. An algorithm to estimate this dispersion is tested. (author)

  19. Thorbecke Revisited : The Role of Doctrinaire Liberalism in Dutch Politics

    NARCIS (Netherlands)

    Drentje, Jan

    2011-01-01

    Thorbecke Revisited: The Role of Doctrinaire Liberalism in Dutch Politics In the political history of the nineteenth century Thorbecke played a crucial role. As the architect of the 1848 liberal constitutional reform he led three cabinets. In many ways he dominated the political discourse during the

  20. Faraday effect revisited: sum rules and convergence issues

    DEFF Research Database (Denmark)

    Cornean, Horia; Nenciu, Gheorghe

    2010-01-01

    This is the third paper of a series revisiting the Faraday effect. The question of the absolute convergence of the sums over the band indices entering the Verdet constant is considered. In general, sum rules and traces per unit volume play an important role in solid-state physics, and they give...

  1. A Multi-Level Model of Moral Functioning Revisited

    Science.gov (United States)

    Reed, Don Collins

    2009-01-01

    The model of moral functioning scaffolded in the 2008 "JME" Special Issue is here revisited in response to three papers criticising that volume. As guest editor of that Special Issue I have formulated the main body of this response, concerning the dynamic systems approach to moral development, the problem of moral relativism and the role of…

  2. Three Mile Island accident

    International Nuclear Information System (INIS)

    Barre, B.; Olivier, E.; Roux, J.P.; Pelle, P.

    2010-01-01

    Deluded by equivocal instrumentation signals, operators at TMI-2 (Three Mile Island - unit 2) misunderstood what was going on in the reactor and for 2 hours were taking inadequate decisions that turned a reactor incident into a major nuclear event that led to the melting of about one third of the core. The TMI accident had worldwide impacts in the domain of nuclear safety. The main consequences in France were: 1) the introduction of the major accident approach and the reinforcement of crisis management; 2) the improvement of the reactor design, particularly that of the pressurizer valves; 3) the implementation of safety probabilistic studies; 4) a better taking into account of the feedback experience in reactor operations; and 5) a better taking into account of the humane factor in reactor safety. (A.C.)

  3. Three Mile Island update

    International Nuclear Information System (INIS)

    Snyder, B.J.

    1984-01-01

    Almost six years after the accident at Three Mile Island-2, cleanup operations are proceeding and the financial condition of the owners has improved. The author reviews some of the cleanup activities and notes the milestones ahead before reaching the September, 1988 target date for completion. A decision to decommission or refurbish will follow the completion of fuel removal activities in 1987. The cleanup has produced considerable data and useful information. In particular, the experience of large-scale decontamination and radioactive waste processing, along with information on fission product transport, is relevant for maintenance and safe operation of other plants. Both macro- and microscopic examination of the core could help in developing safer reactors in the future. 3 figures, 1 table

  4. PWR: nuclear islands

    International Nuclear Information System (INIS)

    1989-01-01

    Framatome and its partners have produced this glossary of technical terms that can be used in writing English language documents relating to power plants (nuclear islands, individual components, nuclear services, etc.) with the hope of improving the quality of the documents intended for their clients, suppliers and partners and for others. This glossary will be particularly useful to the translators and authors of technical proposals, design documents, manufacturing documents, construction and operating documents concerning Pressurized Water Reactors written in English or French. It can also be useful as a reference document for students, researchers, journalists, etc., having to write on this subject. We would like to thank all those individuals working at the Ministere de la Recherche et de la Technologie, Electricite de France, Jeumont Schneider and Framatome who have contributed to this glossary. We would also appreciate any comments or sugestions intended to improve subsequent editions of this glossary [fr

  5. Mauritius - a Sustainable Island

    DEFF Research Database (Denmark)

    Larsen, Anders

    2010-01-01

    production is determined to be the way forward. A step in this direction is to devolve upon citizens the ability and motivation to produce electricity via small-scale distributed generation (SSDG), i.e. wind, photovoltaic and hydro installations below 50 kW. Given that SSDG is more expensive per installed......The Government of Mauritius has a long-term vision of transforming Mauritius into a sustainable Island. One important element towards the achievement of this vision is to increase the country's renewable energy usage and thereby reducing dependence on fossil fuels. Democratisation of energy...... capacity than the existing much larger power plants, subsidies are needed so as to provide incentives to small independent power producers (SIPP), households and firms to invest in SSDG.The paper presents the context, the theoretical considerations and the proposed incentive schemes to enable electricity...

  6. SRTM Anaglyph: Fiji Islands

    Science.gov (United States)

    2000-01-01

    The Sovereign Democratic Republic of the Fiji Islands, commonly known as Fiji, is an independent nation consisting of some 332 islands surrounding the Koro Sea in the South Pacific Ocean. This topographic image shows Viti Levu, the largest island in the group. With an area of 10,429 square kilometers (about 4000 square miles), it comprises more than half the area of the Fiji Islands. Suva, the capital city, lies on the southeast shore. The Nakauvadra, the rugged mountain range running from north to south, has several peaks rising above 900 meters (about 3000 feet). Mount Tomanivi, in the upper center, is the highest peak at 1324 meters (4341 feet). The distinct circular feature on the north shore is the Tavua Caldera, the remnant of a large shield volcano that was active about 4 million years ago. Gold has been mined on the margin of the caldera since the 1930s. The Nadrau plateau is the low relief highland in the center of the mountain range. The coastal plains in the west, northwest and southeast account for only 15 percent of Viti Levu's area but are the main centers of agriculture and settlement.This shaded relief anaglyph image was generated using preliminary topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data from the top (north) to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. The stereoscopic effect was created by first draping the shaded relief image back over the topographic data and then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.This image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument

  7. Who should do the dishes now? Revisiting gender and housework in contemporary urban South Wales

    OpenAIRE

    Mannay, Dawn

    2016-01-01

    This chapter revisits Jane Pilcher’s (1994) seminal work ‘Who should do the dishes? Three generations of Welsh women talking about men and housework’, which was originally published in Our Sister’s Land: the changing identities of women in Wales. As discussed in the introductory chapter, I began revisiting classic Welsh studies as part of my doctoral study Mothers and daughters on the margins: gender, generation and education (Mannay, 2012); this lead to the later publication of a revisiting ...

  8. A Structural Equation Model of Risk Perception of Rockfall for Revisit Intention

    OpenAIRE

    Ya-Fen Lee; Yun-Yao Chi

    2014-01-01

    The study aims to explore the relationship between risk perception of rockfall and revisit intention using a Structural Equation Modeling (SEM) analysis. A total of 573 valid questionnaires are collected from travelers to Taroko National Park, Taiwan. The findings show the majority of travelers have the medium perception of rockfall risk, and are willing to revisit the Taroko National Park. The revisit intention to Taroko National Park is influenced by hazardous preferences, willingness-to-pa...

  9. Potential Demand of Relatively New and Emerging Marine Ecotourism in Kei Islands

    Science.gov (United States)

    Dewa Ayu Raka Susanti, Ida I.; Teniwut, Wellem A.; Kahfi, Syahibul; M. K Teniwut, Roberto; Picaulima, Simon; Hungan, Marselus; Rahantoknam, Meyske; Hasyim, Cawalinya; Rahakbauw, Siska D.; Renjaan, M. R.; Ngabalin, Anna M.; Ngangun, Tati A.; Pentury, Frischila; Betaubun, Kamilius D.; Ngamel, A. K.; Ohoiwutun, Elisabeth C.

    2017-10-01

    One of the main resources for the economic development of coastal are marine ecotourism. Although for developing country such as Indonesia and especially for an area that located far from a big city like Kei Islands in Maluku, development of marine ecotourism might face a greater challenge than any other places. Considering the potential for multiplier effect on economic of a coastal community, the purpose of this research was to analyze and measure the economic value of new, raw and emerging marine ecotourism spot and determine the demand based on domestic tourist perspective. We pick five new and emerging marine ecotourism spots in this area as case study and used purposive sampling technique to target potential domestic tourist who have visited those five marine ecotourism spots and measure their preference and measure their demand potential by used willingness to revisit (WTR) and logistic regression for analyze the data, this research conducted in Kei Islands, Indonesia. This result can provide broad and comprehensive perspective on developing marine ecotourism in a mildly isolated coastal area like Kei Islands and place similar.

  10. Bamboo Diversity in Sumba Island

    Directory of Open Access Journals (Sweden)

    KARSONO

    2005-04-01

    Full Text Available Bamboo is one of the economic plant which grow widely in the villages and have been used by the local people in the villages. Indonesia has about 10% of the world bamboo, 50% among them was endemic to Indonesia. According Widjaja (2001 Lesser Sunda Island which consists of Lombok, Sumbawa, Flores, Timor, Sumba and other small island eastern of Flores has 14 bamboo species, however, the information from the Sumba Island was lacking because of lacking data from this area except one species which was proposed by S. Soenarko in 1977 where the type specimens was collected by Iboet 443 in 1925. To fullfill data from the Sumba Island, an exploration to this area has been conducted on July 2003. The observation was done in West Sumba and East Sumba District, especially in two natioal parks at both districts. According to this inventory study in the Sumba Island, there were 10 bamboo species in Sumba Island, 1 species among them (Dinochloa sp. was a new species which has not been collected before, whereas the other species (Dinochloa kostermansiana has a new addition record from this area. The bamboo species in Sumba Island were Bambusa blumeana, Bambusa vulgaris, Dendocalamus asper, Dinochloa kostermansiana, Dinochloa sp., Gigantochloa atter, Nastus reholtumianus, Phyllostachys aurea, Schisotachyum brachycladum and Schizostachyum lima. From 10 recorded species, the genera Dinochloa and Nastus grow wild in the forest, whereas another species grow widly or cultivated in the garden. Furthermore, the genus Dinochloa was the only genus grow climbing. The endemic species found in Sumba Island was Nastus reholttumianus, whereas Dinochloa kostermansiana was also found in Flores Island.

  11. Biogeography in deep time - What do phylogenetics, geology, and paleoclimate tell us about early platyrrhine evolution?

    Science.gov (United States)

    Kay, Richard F

    2015-01-01

    America has been a center for platyrrhine diversification since platyrrhines arrived on the continent in the middle Cenozoic. Platyrrhines dispersed from tropical South America to Patagonia at ∼25-24 Ma via a "Paraná Portal" through eastern South America across a retreating Paranense Sea. Phylogenetic bracketing suggests Antillean primates arrived via a sweepstakes route or island chain from northern South America in the Early Miocene, not via a proposed land bridge or island chain (GAARlandia) in the Early Oligocene (∼34 Ma). Patagonian and Antillean platyrrhines went extinct without leaving living descendants, the former at the end of the Early Miocene and the latter within the past six thousand years. Molecular evidence suggests crown platyrrhines arrived in Central America by crossing an intermittent connection through the Isthmus of Panama at or after 3.5Ma. Any more ancient Central American primates, should they be discovered, are unlikely to have given rise to the extant Central American taxa in situ. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Highway 61 Revisited: Bob Dilan i francuski poststrukturalizam / Highway 61 Revisited: Bob Dilan and French Poststructuralism

    Directory of Open Access Journals (Sweden)

    Nikola Dedić

    2013-06-01

    Full Text Available The main aim of this text is to show parallels between rock music and poststructuralist philosophy. As a case study one of the most celebrated rock albums of all times – Bob Dylan’s Highway 61 Revisited from 1965 is taken. It is one of the crucial albums in the history of popular culture which influenced further development of rock music within American counter culture of the 60s. Dylan’s turn from the politics of American New Left and folk movement, his relation towards the notions of the author and intertextuality, and his connection with experimental usage of language in the manner of avant-garde and neoavant-garde poetry, are juxtaposed with the main philosophical standpoints of Jean-François Lyotard, Jean Baudrillard, Roland Barthes and Julia Kristeva which historically and chronologically coincide with the appearance of Dylan’s album.

  13. Reliving Island Life: Staging Stories of the Blasket Islands

    Directory of Open Access Journals (Sweden)

    Daithí Kearney

    2017-10-01

    Full Text Available The Blasket Islands are located off the south-west coast of Ireland. No longer inhabited, the Great Blasket Island and its distinctive culture have been documented by a variety of writers and are celebrated today in an interpretative centre on the mainland and in performances by Siamsa Tíre, The National Folk Theatre of Ireland. “Siamsa” developed from local initiatives in North Kerry during the early 1960s and is located today in Tralee, Co. Kerry. It aims to present Irish folklore and folk culture through the medium of theatre involving music, song, dance and mime but invariably no dialogue. In this paper, I focus on the production Oiléan, based loosely on the stories of the Blasket Islanders, which was initially devised as part of the fiftieth anniversary commemoration of the departure of the last inhabitants of the islands in 2003.

  14. The coordinate coherent states approach revisited

    International Nuclear Information System (INIS)

    Miao, Yan-Gang; Zhang, Shao-Jun

    2013-01-01

    We revisit the coordinate coherent states approach through two different quantization procedures in the quantum field theory on the noncommutative Minkowski plane. The first procedure, which is based on the normal commutation relation between an annihilation and creation operators, deduces that a point mass can be described by a Gaussian function instead of the usual Dirac delta function. However, we argue this specific quantization by adopting the canonical one (based on the canonical commutation relation between a field and its conjugate momentum) and show that a point mass should still be described by the Dirac delta function, which implies that the concept of point particles is still valid when we deal with the noncommutativity by following the coordinate coherent states approach. In order to investigate the dependence on quantization procedures, we apply the two quantization procedures to the Unruh effect and Hawking radiation and find that they give rise to significantly different results. Under the first quantization procedure, the Unruh temperature and Unruh spectrum are not deformed by noncommutativity, but the Hawking temperature is deformed by noncommutativity while the radiation specturm is untack. However, under the second quantization procedure, the Unruh temperature and Hawking temperature are untack but the both spectra are modified by an effective greybody (deformed) factor. - Highlights: ► Suggest a canonical quantization in the coordinate coherent states approach. ► Prove the validity of the concept of point particles. ► Apply the canonical quantization to the Unruh effect and Hawking radiation. ► Find no deformations in the Unruh temperature and Hawking temperature. ► Provide the modified spectra of the Unruh effect and Hawking radiation.

  15. Backwardation in energy futures markets: Metalgesellschaft revisited

    International Nuclear Information System (INIS)

    Charupat, N.; Deaves, R.

    2003-01-01

    Energy supply contracts negotiated by the US Subsidiary of Metalgesellschaft Refining and Marketing (MGRM), which were the subject of much subsequent debate, are re-examined. The contracts were hedged by the US Subsidiary barrel-for-barrel using short-dated energy derivatives. When the hedge program experienced difficulties, the derivatives positions were promptly liquidated by the parent company. Revisiting the MGRM contracts also provides the opportunity to explore the latest evidence on backwardation in energy markets. Accordingly, the paper discusses first the theoretical reasons for backwardation, followed by an empirical examination using the MGRM data available at the time of the hedge program in 1992 and a second set of data that became available in 2000. By using a more up-to-date data set covering a longer time period and by controlling the time series properties of the data, the authors expect to provide more reliable empirical evidence on the behaviour of energy futures prices. Results based on the 1992 data suggest that the strategy employed by MGRM could be expected to be profitable while the risks are relatively low. However, analysis based on the 2000 data shows lower, although still significant profits, but higher risks. The final conclusion was that the likelihood of problems similar to those faced by MGRM in 1992 are twice as high with the updated 2000 data, suggesting that the risk-return pattern of the stack-and-roll hedging strategy using short-dated energy future contracts to hedge long-tem contracts is less appealing now than when MGRM implemented its hedging program in 1992. 24 refs., 3 tabs., 6 figs

  16. Clifford Algebra Implying Three Fermion Generations Revisited

    International Nuclear Information System (INIS)

    Krolikowski, W.

    2002-01-01

    The author's idea of algebraic compositeness of fundamental particles, allowing to understand the existence in Nature of three fermion generations, is revisited. It is based on two postulates. Primo, for all fundamental particles of matter the Dirac square-root procedure √p 2 → Γ (N) ·p works, leading to a sequence N=1, 2, 3, ... of Dirac-type equations, where four Dirac-type matrices Γ (N) μ are embedded into a Clifford algebra via a Jacobi definition introducing four ''centre-of-mass'' and (N - 1) x four ''relative'' Dirac-type matrices. These define one ''centre-of-mass'' and N - 1 ''relative'' Dirac bispinor indices. Secundo, the ''centre-of-mass'' Dirac bispinor index is coupled to the Standard Model gauge fields, while N - 1 ''relative'' Dirac bispinor indices are all free indistinguishable physical objects obeying Fermi statistics along with the Pauli principle which requires the full antisymmetry with respect to ''relative'' Dirac indices. This allows only for three Dirac-type equations with N = 1, 3, 5 in the case of N odd, and two with N = 2, 4 in the case of N even. The first of these results implies unavoidably the existence of three and only three generations of fundamental fermions, namely leptons and quarks, as labelled by the Standard Model signature. At the end, a comment is added on the possible shape of Dirac 3 x 3 mass matrices for four sorts of spin-1/2 fundamental fermions appearing in three generations. For charged leptons a prediction is m τ = 1776.80 MeV, when the input of experimental m e and m μ is used. (author)

  17. Solar system anomalies: Revisiting Hubble's law

    Science.gov (United States)

    Plamondon, R.

    2017-12-01

    This paper investigates the impact of a new metric recently published [R. Plamondon and C. Ouellet-Plamondon, in On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories, edited by K. Rosquist, R. T. Jantzen, and R. Ruffini (World Scientific, Singapore, 2015), p. 1301] for studying the space-time geometry of a static symmetric massive object. This metric depends on a complementary error function (erfc) potential that characterizes the emergent gravitation field predicted by the model. This results in two types of deviations as compared to computations made on the basis of a Newtonian potential: a constant and a radial outcome. One key feature of the metric is that it postulates the existence of an intrinsic physical constant σ , the massive object-specific proper length that scales measurements in its surroundings. Although σ must be evaluated experimentally, we use a heuristic to estimate its value and point out some latent relationships between the Hubble constant, the secular increase in the astronomical unit, and the Pioneers delay. Indeed, highlighting the systematic errors that emerge when the effect of σ is neglected, one can link the Hubble constant H 0 to σ Sun and the secular increase V AU to σ Earth . The accuracy of the resulting numerical predictions, H 0 = 74 . 42 ( 0 . 02 ) ( km / s ) / Mpc and V AU ≅ 7.8 cm yr-1 , calls for more investigations of this new metric by specific experts. Moreover, we investigate the expected impacts of the new metric on the flyby anomalies, and we revisit the Pioneers delay. It is shown that both phenomena could be partly taken into account within the context of this unifying paradigm, with quite accurate numerical predictions. A correction for the osculating asymptotic velocity at the perigee of the order of 10 mm/s and an inward radial acceleration of 8 . 34 × 10 - 10 m / s 2 affecting the Pioneer ! space crafts could be explained by this new model.

  18. Double neutron stars: merger rates revisited

    Science.gov (United States)

    Chruslinska, Martyna; Belczynski, Krzysztof; Klencki, Jakub; Benacquista, Matthew

    2018-03-01

    We revisit double neutron star (DNS) formation in the classical binary evolution scenario in light of the recent Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo DNS detection (GW170817). The observationally estimated Galactic DNS merger rate of R_MW = 21^{+28}_{-14} Myr-1, based on three Galactic DNS systems, fully supports our standard input physics model with RMW = 24 Myr-1. This estimate for the Galaxy translates in a non-trivial way (due to cosmological evolution of progenitor stars in chemically evolving Universe) into a local (z ≈ 0) DNS merger rate density of Rlocal = 48 Gpc-3 yr-1, which is not consistent with the current LIGO/Virgo DNS merger rate estimate (1540^{+3200}_{-1220} Gpc-3 yr-1). Within our study of the parameter space, we find solutions that allow for DNS merger rates as high as R_local ≈ 600^{+600}_{-300} Gpc-3 yr-1 which are thus consistent with the LIGO/Virgo estimate. However, our corresponding BH-BH merger rates for the models with high DNS merger rates exceed the current LIGO/Virgo estimate of local BH-BH merger rate (12-213 Gpc-3 yr-1). Apart from being particularly sensitive to the common envelope treatment, DNS merger rates are rather robust against variations of several of the key factors probed in our study (e.g. mass transfer, angular momentum loss, and natal kicks). This might suggest that either common envelope development/survival works differently for DNS (˜10-20 M⊙ stars) than for BH-BH (˜40-100 M⊙ stars) progenitors, or high black hole (BH) natal kicks are needed to meet observational constraints for both types of binaries. Our conclusion is based on a limited number of (21) evolutionary models and is valid within this particular DNS and BH-BH isolated binary formation scenario.

  19. Clifford Algebra Implying Three Fermion Generations Revisited

    Science.gov (United States)

    Krolikowski, Wojciech

    2002-09-01

    The author's idea of algebraic compositeness of fundamental particles, allowing to understand the existence in Nature of three fermion generations, is revisited. It is based on two postulates. Primo, for all fundamental particles of matter the Dirac square-root procedure √ {p2} → {Γ }(N)p works, leading to a sequence N = 1,2,3, ... of Dirac-type equations, where four Dirac-type matrices {Γ }(N)μ are embedded into a Clifford algebra via a Jacobi definition introducing four ``centre-of-mass'' and (N-1)× four ``relative'' Dirac-type matrices. These define one ``centre-of-mass'' and (N-1) ``relative'' Dirac bispinor indices. Secundo, the ``centre-of-mass'' Dirac bispinor index is coupled to the Standard Model gauge fields, while (N-1) ``relative'' Dirac bispinor indices are all free indistinguishable physical objects obeying Fermi statistics along with the Pauli principle which requires the full antisymmetry with respect to ``relative'' Dirac indices. This allows only for three Dirac-type equations with N = 1,3,5 in the case of N odd, and two with N = 2,4 in the case of N even. The first of these results implies unavoidably the existence of three and only three generations of fundamental fermions, namely leptons and quarks, as labelled by the Standard Model signature. At the end, a comment is added on the possible shape of Dirac 3x3 mass matrices for four sorts of spin-1/2 fundamental fermions appearing in three generations. For charged leptons a prediction is mτ = 1776.80 MeV, when the input of experimental me and mμ is used.

  20. Oak restoration trials: Santa Catalina Island

    Science.gov (United States)

    Lisa Stratton

    2002-01-01

    Two restoration trials involving four oak species have been implemented as part of a larger restoration program for Catalina Island. In 1997 the Catalina Island Conservancy began an active program of restoration after 50 years of ranching and farming activities on the island. The restoration program includes removing feral goats and pigs island-wide and converting 80...

  1. Pathways and Distribution of Marine Debris Around a Remote Caribbean Island, Little Cayman

    Science.gov (United States)

    Camp, L.; Marsh, L.; O'Keefe, A.; Duran, J.; Wilcox, S. M.; James, R.; Cowan, E.

    2011-12-01

    Marine Debris is a major environmental concern that affects all levels of marine life. On remote beaches in the Caribbean, where human populations are minimal, marine debris is largely deposited by ocean currents. The ocean is estimated to be littered with over 6 million metric tons of trash per year with 90% coming from land sources, but little is known about the exact sources and pathways for the debris. In 2006, on Little Cayman Island, coastal debris was collected at two coastal areas where removal of debris had not occurred in at least 9 years and along 2000 meters squared. One site was located on the north side, while the other site was located on the south side of the island. Both sites were located in reef-protected coastal zones. These two sites were revisited in 2007, 2010, and 2011 to determine the volume, weight, and type of debris arriving annually and to assess the importance of different coastal processes in deposition. In 2011, eight turtle nesting beaches were added to the study and a total of 11,186 liters of debris was collected from 1600 meters of coastline. The island lies in a northeast southwest orientation. The south-side of the island is influenced largely by prevailing trade winds, currents and tropical storms, traveling across the Caribbean from the east. Currents, eddies, and Norwesters would presumably deposit debris on the north side of the island. Approximately five times the amount of debris is deposited on the south side of the island than on the north side of the island. From the total debris collected, 72.45% was plastic, 8.23% shoes, 6.37% ropes & nets , 5.13% glass, 4.37% styrofoam, and 3.44% contained other debris. The marine debris originated in 8 different countries, and it is estimated that there is collectively 223,721 liters (11,635 kg) covering the shores of the entire island. Remarkably, debris found on Little Cayman in 2011 was traced to the 2010 Haitian earthquake relief effort.

  2. THE INFLUENCE OF DESTINATION IMAGE AND TOURIST SATISFACTION TOWARD REVISIT INTENTION OF SETU BABAKAN BETAWI CULTURAL VILLAGE

    OpenAIRE

    Wibowo, Setyo Ferry; Sazali, Adnan; Kresnamurti R. P., Agung

    2016-01-01

    The purpose of this research are: 1) To find out the description of destination image, tourist satisfaction, and revisit intention of Betawi cultural village Setu Babakan, 2) test empirically the influence of destination image toward revisit intention of Betawi cultural village Setu Babakan, 3) test empirically the influence of tourist satisfaction toward revisit intention of Betawi cultural village Setu Babakan, 4) test empirically the influence of destination image toward revisit intention ...

  3. ASTER Images the Island of Hawaii

    Science.gov (United States)

    2000-01-01

    These images of the Island of Hawaii were acquired on March 19, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. Data are shown from the short wavelength and thermal infrared spectral regions, illustrating how different and complementary information is contained in different parts of the spectrum.Left image: This false-color image covers an area 60 kilometers (37 miles) wide and 120 kilometers (75 miles) long in three bands of the short wavelength infrared region. While, much of the island was covered in clouds, the dominant central Mauna Loa volcano, rising to an altitude of 4115 meters (13,500 feet), is cloud-free. Lava flows can be seen radiating from the central crater in green and black tones. As they reach lower elevations, the flows become covered with vegetation, and their image color changes to yellow and orange. Mauna Kea volcano to the north of Mauna Loa has a thin cloud-cover, producing a bluish tone on the image. The ocean in the lower right appears brown due to the color processing.Right image: This image is a false-color composite of three thermal infrared bands. The brightness of the colors is proportional to the temperature, and the hues display differences in rock composition. Clouds are black, because they are the coldest objects in the scene. The ocean and thick vegetation appear dark green because they are colder than bare rock surfaces, and have no thermal spectral features. Lava flows are shades of magenta, green, pink and yellow, reflecting chemical changes due to weathering and relative age differences.Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched

  4. Multilocus genetic diversity and historical biogeography of the endemic wall lizard from Ibiza and Formentera, Podarcis pityusensis (Squamata: Lacertidae).

    Science.gov (United States)

    Rodríguez, V; Brown, R P; Terrasa, B; Pérez-Mellado, V; Castro, J A; Picornell, A; Ramon, M M

    2013-10-01

    Two monophyletic sister species of wall lizards inhabit the two main groups of Balearic Islands: Podarcis lilfordi from islets and small islands around Mallorca and Menorca and Podarcis pityusensis from Ibiza, Formentera and associated islets. Genetic diversity within the endangered P. lilfordi has been well characterized, but P. pityusensis has not been studied in depth. Here, 2430 bp of mtDNA and 15 microsatellite loci were analysed from P. pityusensis populations from across its natural range. Two main genetic groupings were identified, although geographical structuring differed slightly between the mtDNA and the nuclear loci. In general, individuals from islets/islands adjacent to the main island of Ibiza were genetically distinct from those from Formentera and the associated Freus islands for both mtDNA and the nuclear loci. However, most individuals from the island of Ibiza were grouped with neighbouring islets/islands for nuclear loci, but with Formentera and Freus islands for the mitochondrial locus. A time-calibrated Bayesian tree was constructed for the principal mitochondrial lineages within the Balearics, using the multispecies coalescent model, and provided statistical support for divergence of the two main P. pityusensis lineages 0.111-0.295 Ma. This suggests a mid-late Pleistocene intraspecific divergence, compared with an early Pleistocene divergence in P. lilfordi, and postdates some major increases in sea level between 0.4 and 0.6 Ma, which may have flooded Formentera. The program IMa2 provided a posterior divergence time of 0.089-0.221 Ma, which was similar to the multispecies coalescent tree estimate. More significantly, it indicated low but asymmetric effective gene copy migration rates, with higher migration from Formentera to Ibiza populations. Our findings suggest that much of the present-day diversity may have originated from a late Pleistocene colonization of one island group from the other, followed by allopatric divergence of these

  5. The Three Mile Island Disaster.

    Science.gov (United States)

    Crosby, Emeral

    1980-01-01

    For the past decade, education has been experiencing meltdown, explosions, radiation leaks, heat pollution, and management crises, just like the Three Mile Island disaster. This article offers suggestions on how to deal with these problems. (Author/LD)

  6. Ship impact against protection islands

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    1997-01-01

    The five most exposed piers and the anchor blocks on the East Bridge shall be protected by aritificial islands. Extensive analytical and experimental investitations were carried out to verify the efficiency of how these protection works....

  7. Three Mile Island Accident Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Three Mile Island Accident Data consists of mostly upper air and wind observations immediately following the nuclear meltdown occurring on March 28, 1979, near...

  8. Archaeology of Bet Dwarka Island

    Digital Repository Service at National Institute of Oceanography (India)

    Sundaresh; Gaur, A.S.

    Explorations along the shore and in the intertidal zone at Bet Dwarka island, Gujarat, India were carried out by the Marine Archaeology Centre of National Institute of Oceanography (NIO), Goa, India between 1981-1994. Artefacts of both...

  9. Tourism impacts of Three Mile Island and other adverse events: implications for Lincoln County and other rural counties bisected by radioactive wastes intended for Yucca Mountain

    International Nuclear Information System (INIS)

    Himmelberger, J.J.; Baughman, M.; Ogneva-Himmelberger, Y.A.

    1995-01-01

    Whether the proposed Yucca Mountain nuclear waste repository system will adversely impact tourism in southern Nevada is an open question of particular importance to visitor-oriented rural counties bisected by planned waste transportation corridors (highway or rail). As part of one such county's repository impact assessment program, tourism implications of Three Mile Island (TMI) and other major hazard events have been revisited to inform ongoing county-wide socioeconomic assessments and contingency planning efforts. This paper summarizes key research implications of such research as applied to Lincoln County, Nevada. Implications for other rural counties are discussed in light of the research findings

  10. Tourism impacts of Three Mile Island and other adverse events: Implications for Lincoln County and other rural counties bisected by radioactive wastes intended for Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    Himmelberger, J.J.; Ogneva-Himmelberger, Y.A. [Clark Univ., Worcester, MA (United States); Baughman, M. [Interech Services Corporation, Carson City, NV (United States)

    1995-11-01

    Whether the proposed Yucca Mountain nuclear waste repository system will adversely impact tourism in southern Nevada is an open question of particular importance to visitor-oriented rural counties bisected by planned waste transportation corridors (highway or rail). As part of one such county`s repository impact assessment program, tourism implications of Three Mile Island (TMI) and other major hazard events have been revisited to inform ongoing county-wide socioeconomic assessments and contingency planning efforts. This paper summarizes key research implications of such research as applied to Lincoln County, Nevada. Implications for other rural counties are discussed in light of the research findings. 29 refs., 3 figs., 1 tab.

  11. Biogeography and evolution of the Carassius auratus-complex in East Asia

    Directory of Open Access Journals (Sweden)

    Iguchi Kei'ichiro

    2010-01-01

    Full Text Available Abstract Background Carassius auratus is a primary freshwater fish with bisexual diploid and unisexual gynogenetic triploid lineages. It is distributed widely in Eurasia and is especially common in East Asia. Although several genetic studies have been conducted on C. auratus, they have not provided clear phylogenetic and evolutionary descriptions of this fish, probably due to selection bias in sampling sites and the DNA regions analysed. As the first step in clarifying the evolutionary entity of the world's Carassius fishes, we attempted to clarify the phylogeny of C. auratus populations distributed in East Asia. Results We conducted a detailed analysis of a large dataset of mitochondrial gene sequences [CR, 323 bp, 672 sequences (528 sequenced + 144 downloaded; CR + ND4 + ND5 + cyt b, 4669 bp in total, 53 sequences] obtained from C. auratus in East Asia. Our phylogeographic analysis revealed two superlineages, one distributed mainly among the Japanese main islands and the other in various regions in and around the Eurasian continent, including the Ryukyus and Taiwan. The two superlineages include seven lineages with high regional specificity that are composed of endemic populations indigenous to each region. The divergence time of the seven lineages was estimated to be 0.2 million years ago (Mya by a fossil-based method and 1.0-1.9 Mya by the molecular clock method. The antiquity and endemism of these lineages suggest that they are native to their respective regions, although some seem to have been affected by the artificial introduction of C. auratus belonging to other lineages. Triploids of C. auratus did not form a monophyletic lineage but were clustered mostly with sympatric diploids. Conclusions The results of the present study revealed the existence of two superlineages of C. auratus in East Asia that include seven lineages endemic to each of the seven regions examined. The lack of substantial genetic separation between triploids and

  12. Historical biogeography and diversification of truffles in the Tuberaceae and their newly identified southern hemisphere sister lineage.

    Science.gov (United States)

    Bonito, Gregory; Smith, Matthew E; Nowak, Michael; Healy, Rosanne A; Guevara, Gonzalo; Cázares, Efren; Kinoshita, Akihiko; Nouhra, Eduardo R; Domínguez, Laura S; Tedersoo, Leho; Murat, Claude; Wang, Yun; Moreno, Baldomero Arroyo; Pfister, Donald H; Nara, Kazuhide; Zambonelli, Alessandra; Trappe, James M; Vilgalys, Rytas

    2013-01-01

    Truffles have evolved from epigeous (aboveground) ancestors in nearly every major lineage of fleshy fungi. Because accelerated rates of morphological evolution accompany the transition to the truffle form, closely related epigeous ancestors remain unknown for most truffle lineages. This is the case for the quintessential truffle genus Tuber, which includes species with socio-economic importance and esteemed culinary attributes. Ecologically, Tuber spp. form obligate mycorrhizal symbioses with diverse species of plant hosts including pines, oaks, poplars, orchids, and commercially important trees such as hazelnut and pecan. Unfortunately, limited geographic sampling and inconclusive phylogenetic relationships have obscured our understanding of their origin, biogeography, and diversification. To address this problem, we present a global sampling of Tuberaceae based on DNA sequence data from four loci for phylogenetic inference and molecular dating. Our well-resolved Tuberaceae phylogeny shows high levels of regional and continental endemism. We also identify a previously unknown epigeous member of the Tuberaceae--the South American cup-fungus Nothojafnea thaxteri (E.K. Cash) Gamundí. Phylogenetic resolution was further improved through the inclusion of a previously unrecognized Southern hemisphere sister group of the Tuberaceae. This morphologically diverse assemblage of species includes truffle (e.g. Gymnohydnotrya spp.) and non-truffle forms that are endemic to Australia and South America. Southern hemisphere taxa appear to have diverged more recently than the Northern hemisphere lineages. Our analysis of the Tuberaceae suggests that Tuber evolved from an epigeous ancestor. Molecular dating estimates Tuberaceae divergence in the late Jurassic (~156 million years ago), with subsequent radiations in the Cretaceous and Paleogene. Intra-continental diversification, limited long-distance dispersal, and ecological adaptations help to explain patterns of truffle

  13. Phylogeny, biogeography and character evolution in the tribe Desmodieae (Fabaceae: Papilionoideae), with special emphasis on the New Caledonian endemic genera.

    Science.gov (United States)

    Jabbour, Florian; Gaudeul, Myriam; Lambourdière, Josie; Ramstein, Guillaume; Hassanin, Alexandre; Labat, Jean-Noël; Sarthou, Corinne

    2018-01-01

    The nearly cosmopolitan tribe Desmodieae (Fabaceae) includes many important genera for medicine and forage. However, the phylogenetic relationships among the infratribal groups circumscribed using morphological traits are still poorly known. In this study, we used chloroplast (rbcL, psbA-trnH) and nuclear (ITS-1) DNA sequences to investigate the molecular phylogeny and historical biogeography of Desmodieae, and infer ancestral states for several vegetative and reproductive traits. Three groups, corresponding to the Desmodium, Lespedeza, and Phyllodium groups sensu Ohashi were retrieved in the phylogenetic analyses. Conflicts in the topologies inferred from the chloroplast and nuclear datasets were detected. For instance, the Lespedeza clade was sister to the groups Phyllodium+Desmodium based on chloroplast DNA, but nested within the Desmodium group based on ITS-1. Moreover, the New Caledonian endemic genera Arthroclianthus and Nephrodesmus were not monophyletic but together formed a clade, which also included Hanslia and Ohwia based on chloroplast DNA. The hypothetical common ancestor of Desmodieae was dated to the Middle Oligocene (ca. 28.3Ma) and was likely an Asian shrub or tree producing indehiscent loments. Several colonization events towards Oceania, America, and Africa occurred (all less than ca. 17.5Ma), most probably through long distance dispersal. The fruits of Desmodieae repeatedly evolved from indehiscence to dehiscence. We also showed that indehiscent loments allow for more variability in the number of seeds per fruit than indehiscent legumes. Modularity seems here to allow variability in the number of ovules produced in a single ovary. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Genome and metagenome enabled analyses reveal new insight into the global biogeography and potential urea utilization in marine Thaumarchaeota.

    Science.gov (United States)

    Ahlgren, N.; Parada, A. E.; Fuhrman, J. A.

    2016-02-01

    Marine Thaumarchaea are an abundant, important group of marine microbial communities as they fix carbon, oxidize ammonium, and thus contribute to key N and C cycles in the oceans. From an enrichment culture, we have sequenced the complete genome of a new Thaumarchaeota strain, SPOT01. Analysis of this genome and other Thaumarchaeal genomes contributes new insight into its role in N cycling and clarifies the broader biogeography of marine Thaumarchaeal genera. Phylogenomics of Thaumarchaeota genomes reveal coherent separation into clusters roughly equivalent to the genus level, and SPOT01 represents a new genus of marine Thaumarchaea. Competitive fragment recruitment of globally distributed metagenomes from TARA, Ocean Sampling Day, and those generated from a station off California shows that the SPOT01 genus is often the most abundant genus, especially where total Thaumarchaea are most abundant in the overall community. The SPOT01 genome contains urease genes allowing it to use an alternative form of N. Genomic and metagenomic analysis also reveal that among planktonic genomes and populations, the urease genes in general are more frequently found in members of the SPOT01 genus and another genus dominant in deep waters, thus we predict these two genera contribute most significantly to urea utilization among marine Thaumarchaea. Recruitment also revealed broader biogeographic and ecological patterns of the putative genera. The SPOT01 genus was most abundant at colder temperatures (45 degrees). The genus containing Nitrosopumilus maritimus had the highest temperature range, and the genus containing Candidatus Nitrosopelagicus brevis was typically most abundant at intermediate temperatures and intermediate latitudes ( 35-45 degrees). Together these genome and metagenome enabled analyses provide significant new insight into the ecology and biogeochemical contributions of marine archaea.

  15. Around the World in Eight Million Years: Historical Biogeography and Evolution of the Spray Zone Spider Amaurobioides (Araneae: Anyphaenidae)

    Science.gov (United States)

    Opell, Brent D.; Haddad, Charles R.; Raven, Robert J.; Soto, Eduardo M.; Ramírez, Martín J.

    2016-01-01

    Closely related organisms with transoceanic distributions have long been the focus of historical biogeography, prompting the question of whether long-distance dispersal, or tectonic-driven vicariance shaped their current distribution. Regarding the Southern Hemisphere continents, this question deals with the break-up of the Gondwanan landmass, which has also affected global wind and oceanic current patterns since the Miocene. With the advent of phylogenetic node age estimation and parametric bioinformatic advances, researchers have been able to disentangle historical evolutionary processes of taxa with greater accuracy. In this study, we used the coastal spider genus Amaurobioides to investigate the historical biogeographical and evolutionary processes that shaped the modern-day distribution of species of this exceptional genus of spiders. As the only genus of the subfamily Amaurobioidinae found on three Southern Hemisphere continents, its distribution is well-suited to study in the context of Gondwanic vicariance versus long-distance, transoceanic dispersal. Ancestral species of the genus Amaurobioides appear to have undergone several long-distance dispersal events followed by successful establishments and speciation, starting from the mid-Miocene through to the Pleistocene. The most recent common ancestor of all present-day Amaurobioides species is estimated to have originated in Africa after arriving from South America during the Miocene. From Africa the subsequent dispersals are likely to have taken place predominantly in an eastward direction. The long-distance dispersal events by Amaurobioides mostly involved transoceanic crossings, which we propose occurred by rafting, aided by the Antarctic Circumpolar Current and the West Wind Drift. PMID:27732621

  16. Insights into the evolution, biogeography and natural history of the acorn ants, genus Temnothorax Mayr (hymenoptera: Formicidae).

    Science.gov (United States)

    Prebus, Matthew

    2017-12-13

    Temnothorax (Formicidae: Myrmicinae) is a diverse genus of ants found in a broad spectrum of ecosystems across the northern hemisphere. These diminutive ants have long served as models for social insect behavior, leading to discoveries about social learning and inspiring hypotheses about the process of speciation and the evolution of social parasitism. This genus is highly morphologically and behaviorally diverse, and this has caused a great deal of taxonomic confusion in recent years. Past efforts to estimate the phylogeny of this genus have been limited in taxonomic scope, leaving the broader evolutionary patterns in Temnothorax unclear. To establish the monophyly of Temnothorax, resolve the evolutionary relationships, reconstruct the historical biogeography and investigate trends in the evolution of key traits, I generated, assembled, and analyzed two molecular datasets: a traditional multi-locus Sanger sequencing dataset, and an ultra-conserved element (UCE) dataset. Using maximum likelihood, Bayesian, and summary-coalescent based approaches, I analyzed 22 data subsets consisting of 103 ingroup taxa and a maximum of 1.8 million base pairs in 2485 loci. The results of this study suggest an origin of Temnothorax at the Eocene-Oligocene transition, concerted transitions to arboreal nesting habits in several clades during the Oligocene, coinciding with ancient global cooling, and several convergent origins of social parasitism in the Miocene and Pliocene. As with other Holarctic taxa, Temnothorax has a history of migration across Beringia during the Miocene. Temnothorax is corroborated as a natural group, and the notion that many of the historical subgeneric and species group concepts are artificial is reinforced. The strict form of Emery's Rule, in which a socially parasitic species is sister to its host species, is not well supported in Temnothorax.

  17. Historical biogeography and diversification of truffles in the Tuberaceae and their newly identified southern hemisphere sister lineage.

    Directory of Open Access Journals (Sweden)

    Gregory Bonito

    Full Text Available Truffles have evolved from epigeous (aboveground ancestors in nearly every major lineage of fleshy fungi. Because accelerated rates of morphological evolution accompany the transition to the truffle form, closely related epigeous ancestors remain unknown for most truffle lineages. This is the case for the quintessential truffle genus Tuber, which includes species with socio-economic importance and esteemed culinary attributes. Ecologically, Tuber spp. form obligate mycorrhizal symbioses with diverse species of plant hosts including pines, oaks, poplars, orchids, and commercially important trees such as hazelnut and pecan. Unfortunately, limited geographic sampling and inconclusive phylogenetic relationships have obscured our understanding of their origin, biogeography, and diversification. To address this problem, we present a global sampling of Tuberaceae based on DNA sequence data from four loci for phylogenetic inference and molecular dating. Our well-resolved Tuberaceae phylogeny shows high levels of regional and continental endemism. We also identify a previously unknown epigeous member of the Tuberaceae--the South American cup-fungus Nothojafnea thaxteri (E.K. Cash Gamundí. Phylogenetic resolution was further improved through the inclusion of a previously unrecognized Southern hemisphere sister group of the Tuberaceae. This morphologically diverse assemblage of species includes truffle (e.g. Gymnohydnotrya spp. and non-truffle forms that are endemic to Australia and South America. Southern hemisphere taxa appear to have diverged more recently than the Northern hemisphere lineages. Our analysis of the Tuberaceae suggests that Tuber evolved from an epigeous ancestor. Molecular dating estimates Tuberaceae divergence in the late Jurassic (~156 million years ago, with subsequent radiations in the Cretaceous and Paleogene. Intra-continental diversification, limited long-distance dispersal, and ecological adaptations help to explain patterns of

  18. The discovery of new deep-sea hydrothermal vent communities in the southern ocean and implications for biogeography.

    Directory of Open Access Journals (Sweden)

    Alex D Rogers

    2012-01-01

    Full Text Available Since the first discovery of deep-sea hydrothermal vents along the Galápagos Rift in 1977, numerous vent sites and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea hydrothermal vents hosting high-temperature black smokers up to 382.8°C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp., stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae, bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more

  19. Around the World in Eight Million Years: Historical Biogeography and Evolution of the Spray Zone Spider Amaurobioides (Araneae: Anyphaenidae.

    Directory of Open Access Journals (Sweden)

    F Sara Ceccarelli

    Full Text Available Closely related organisms with transoceanic distributions have long been the focus of historical biogeography, prompting the question of whether long-distance dispersal, or tectonic-driven vicariance shaped their current distribution. Regarding the Southern Hemisphere continents, this question deals with the break-up of the Gondwanan landmass, which has also affected global wind and oceanic current patterns since the Miocene. With the advent of phylogenetic node age estimation and parametric bioinformatic advances, researchers have been able to disentangle historical evolutionary processes of taxa with greater accuracy. In this study, we used the coastal spider genus Amaurobioides to investigate the historical biogeographical and evolutionary processes that shaped the modern-day distribution of species of this exceptional genus of spiders. As the only genus of the subfamily Amaurobioidinae found on three Southern Hemisphere continents, its distribution is well-suited to study in the context of Gondwanic vicariance versus long-distance, transoceanic dispersal. Ancestral species of the genus Amaurobioides appear to have undergone several long-distance dispersal events followed by successful establishments and speciation, starting from the mid-Miocene through to the Pleistocene. The most recent common ancestor of all present-day Amaurobioides species is estimated to have originated in Africa after arriving from South America during the Miocene. From Africa the subsequent dispersals are likely to have taken place predominantly in an eastward direction. The long-distance dispersal events by Amaurobioides mostly involved transoceanic crossings, which we propose occurred by rafting, aided by the Antarctic Circumpolar Current and the West Wind Drift.

  20. Population structure, historical biogeography and demographic history of the alpine toad Scutiger ningshanensis in the Tsinling Mountains of Central China.

    Directory of Open Access Journals (Sweden)

    Hongzhe Meng

    Full Text Available Population genetic structure, historical biogeography and historical demography of the alpine toad Scutiger ningshanensis were studied using the combined data mtDNA cytochrome b (cyt b and the mtDNA cytochrome c oxidase subunit I (COI as the molecular markers. This species has high genetic variation. There was a significant genetic differentiation among most populations. Three lineages were detected. The phylogenetic relationship analyses and the SAMOVA (spatial analysis of molecular variance results showed significant phylogeographic structure. 82.15% genetic variation occurred among populations whereas differentiation within populations only contributed 17.85% to the total. Mantel test results showed a significant correlation between the pairwise calculated genetic distance and pairwise calculated geographical distance of the populations (regression coefficient  = 0.001286, correlation coefficient  = 0.77051, p (rrand≥robs  = 0.0185<0.05, indicating the existence of isolation-by-distance pattern of genetic divergence for cyt b + COI sequence, which suggests that the distribution of genetic variation is due to geographical separation rather than natural selection. The population expansion or contraction and genetic differentiation between populations or lineages could be explained by topography and the repetitive uplifts of the Tsinling Mountains and the climatic cycles during the late Pliocene and Pleistocene. S. ningshanensis experienced a rapid population expansion about 40,000 years before present. The current decline in population size was probably caused by anthropogenic disturbance. Current populations of S. ningshanensis are from different refugia though the location of these refugia could not be determined in our study. Topography, climatic changes and repetitive population expansion/contraction together led to the high level of genetic variation in S. ningshanensis. A total of three management units (MUs was determined

  1. Magnetic island formation in tokamaks

    International Nuclear Information System (INIS)

    Yoshikawa, S.

    1989-04-01

    The size of a magnetic island created by a perturbing helical field in a tokamak is estimated. A helical equilibrium of a current- carrying plasma is found in a helical coordinate and the helically flowing current in the cylinder that borders the plasma is calculated. From that solution, it is concluded that the helical perturbation of /approximately/10/sup /minus/4/ of the total plasma current is sufficient to cause an island width of approximately 5% of the plasma radius. 6 refs

  2. Island biodiversity conservation needs palaeoecology

    DEFF Research Database (Denmark)

    Nogué, Sandra; de Nascimento, Lea; Froyd, Cynthia A.

    2017-01-01

    to human activities. Consequently, even the most degraded islands are a focus for restoration, eradication, and monitoring programmes to protect the remaining endemic and/or relict populations. Here, we build a framework that incorporates an assessment of the degree of change from multiple baseline...... and the introduction of non-native species. We provide exemplification of how such approaches can provide valuable information for biodiversity conservation managers of island ecosystems....

  3. Three Mile Island

    International Nuclear Information System (INIS)

    2015-01-01

    This document addresses the Three Mile Island accident which resulted in a core partial fusion. It recalls that other reactors of this plant are still being operated. The operation of this PWR is briefly described, and the main events and phases of the accident are briefly presented (failure of the secondary circuit supply pump, failure of a pressurizer component and wrong information about it, mistaken reaction in the control room, core partial fusion due to insufficient cooling means). It shows that the accident occurred because of a combination of technical failures and human mistakes. This situation has put operator education and organisation into question again. The main actors and their mistakes, weaknesses and responsibilities are indicated: Metropolitan Edison (the operator), the NRC (the US nuclear safety authority). Some key figures are recalled, as well as the context of construction of the plant. Impacts and consequences are reviewed: implementation of new standards, population concern. The document outlines that radioactive exposures due to the accident were minor

  4. Arctic Islands LNG

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, W.

    1977-01-01

    Trans-Canada Pipe Lines Ltd. made a feasibility study of transporting LNG from the High Arctic Islands to a St. Lawrence River Terminal by means of a specially designed and built 125,000 cu m or 165,000 cu m icebreaking LNG tanker. Studies were made of the climatology and of ice conditions, using available statistical data as well as direct surveys in 1974, 1975, and 1976. For on-schedule and unimpeded (unescorted) passage of the LNG carriers at all times of the year, special navigation and communications systems can be made available. Available icebreaking experience, charting for the proposed tanker routes, and tide tables for the Canadian Arctic were surveyed. Preliminary design of a proposed Arctic LNG icebreaker tanker, including containment system, reliquefaction of boiloff, speed, power, number of trips for 345 day/yr operation, and liquefaction and regasification facilities are discussed. The use of a minimum of three Arctic Class 10 ships would enable delivery of volumes of natural gas averaging 11.3 million cu m/day over a period of a year to Canadian markets. The concept appears to be technically feasible with existing basic technology.

  5. Maximal feeding with active prey-switching: A kill-the-winner functional response and its effect on global diversity and biogeography

    Science.gov (United States)

    Vallina, S. M.; Ward, B. A.; Dutkiewicz, S.; Follows, M. J.

    2014-01-01

    Predators' switching towards the most abundant prey is a mechanism that stabilizes population dynamics and helps overcome competitive exclusion of species in food webs. Current formulations of active prey-switching, however, display non-maximal feeding in which the predators' total ingestion decays exponentially with the number prey species (i.e. the diet breadth) even though the total prey biomass stays constant. We analyse three previously published multi-species functional responses which have either active switching or maximal feeding, but not both. We identify the cause of this apparent incompatibility and describe a kill-the-winner formulation that combines active switching with maximal feeding. Active switching is shown to be a community response in which some predators become prey-selective and the formulations with maximal or non-maximal feeding are implicitly assuming different food web configurations. Global simulations using a marine ecosystem model with 64 phytoplankton species belonging to 4 major functional groups show that the species richness and biogeography of phytoplankton are very sensitive to the choice of the functional response for grazing. The phytoplankton biogeography reflects the balance between the competitive abilities for nutrient uptake and the degree of apparent competition which occurs indirectly between species that share a common predator species. The phytoplankton diversity significantly increases when active switching is combined with maximal feeding through predator-mediated coexistence.

  6. The timeline of the lunar bombardment: Revisited

    Science.gov (United States)

    Morbidelli, A.; Nesvorny, D.; Laurenz, V.; Marchi, S.; Rubie, D. C.; Elkins-Tanton, L.; Wieczorek, M.; Jacobson, S.

    2018-05-01

    The timeline of the lunar bombardment in the first Gy of Solar System history remains unclear. Basin-forming impacts (e.g. Imbrium, Orientale), occurred 3.9-3.7 Gy ago, i.e. 600-800 My after the formation of the Moon itself. Many other basins formed before Imbrium, but their exact ages are not precisely known. There is an intense debate between two possible interpretations of the data: in the cataclysm scenario there was a surge in the impact rate approximately at the time of Imbrium formation, while in the accretion tail scenario the lunar bombardment declined since the era of planet formation and the latest basins formed in its tail-end. Here, we revisit the work of Morbidelli et al. (2012) that examined which scenario could be compatible with both the lunar crater record in the 3-4 Gy period and the abundance of highly siderophile elements (HSE) in the lunar mantle. We use updated numerical simulations of the fluxes of asteroids, comets and planetesimals leftover from the planet-formation process. Under the traditional assumption that the HSEs track the total amount of material accreted by the Moon since its formation, we conclude that only the cataclysm scenario can explain the data. The cataclysm should have started ∼ 3.95 Gy ago. However we also consider the possibility that HSEs are sequestered from the mantle of a planet during magma ocean crystallization, due to iron sulfide exsolution (O'Neil, 1991; Rubie et al., 2016). We show that this is likely true also for the Moon, if mantle overturn is taken into account. Based on the hypothesis that the lunar magma ocean crystallized about 100-150 My after Moon formation (Elkins-Tanton et al., 2011), and therefore that HSEs accumulated in the lunar mantle only after this timespan, we show that the bombardment in the 3-4 Gy period can be explained in the accretion tail scenario. This hypothesis would also explain why the Moon appears so depleted in HSEs relative to the Earth. We also extend our analysis of the

  7. Revisit ocean thermal energy conversion system

    International Nuclear Information System (INIS)

    Huang, J.C.; Krock, H.J.; Oney, S.K.

    2003-01-01

    by-products, especially drinking water, aquaculture and mariculture, can easily translate into billions of dollars in business opportunities. The current status of the OTEC system definitely deserves to be carefully revisited. This paper will examine recent major advancements in technology, evaluate costs and effectiveness, and assess the overall market environment of the OTEC system and describe its great renewable energy potential and overall benefits to the nations of the world

  8. Foundation Investigation for Ground Based Radar Project-Kwajalein Island, Marshall Islands

    Science.gov (United States)

    1990-04-01

    iL_ COPY MISCELLANEOUS PAPER GL-90-5 i iFOUNDATION INVESTIGATION FOR GROUND BASED RADAR PROJECT--KWAJALEIN ISLAND, MARSHALL ISLANDS by Donald E...C!assification) Foundatioa Investigation for Ground Based Radar Project -- Kwajalein Island, Marshall Islands 12. PERSONAL AUTHOR(S) Yule, Donald E...investigation for the Ground Based Radar Project -- Kwajalein Island, Marshall Islands , are presented.- eophysical tests comprised of surface refrac- tion

  9. Bryophytes from Simeonof Island in the Shumagin Islands, southwestern Alaska

    Science.gov (United States)

    Schofield, W.B.; Talbot, S. S.; Talbot, S.L.

    2004-01-01

    Simeonof Island is located south of the Alaska Peninsula in the hyperoceanic sector of the middle boreal subzone. We examined the bryoflora of Simeonof Island to determine species composition in an area where no previous collections had been reported. This field study was conducted in sites selected to represent the spectrum of environmental variation within Simeonof Island. Data were analyzed using published reports to compare bryophyte distribution patterns at three levels, the Northern Hemisphere, North America, and Alaska. A total of 271 bryophytes were identified: 202 mosses and 69 liverworts. The annotated list of species for Simeonof Island expands the known range for many species and fills distribution gaps within Hulte??n's Western Pacific Coast district. Maps and notes on the distribution of 14 significant distribution records are presented. Compared with bryophyte distribution in the Northern Hemisphere, the bryoflora of Simeonof Island primarily includes taxa of boreal (55%), temperate (20%), arctic (10%), and cosmopolitan (8%) distribution; 6% of the moss flora are western North America endemics. A description of the bryophytes present in the vegetation and habitat types is provided as is a quantitative analysis of the most frequently occurring bryophytes in crowberry heath.

  10. The significance test controversy revisited the fiducial Bayesian alternative

    CERN Document Server

    Lecoutre, Bruno

    2014-01-01

    The purpose of this book is not only to revisit the “significance test controversy,”but also to provide a conceptually sounder alternative. As such, it presents a Bayesian framework for a new approach to analyzing and interpreting experimental data. It also prepares students and researchers for reporting on experimental results. Normative aspects: The main views of statistical tests are revisited and the philosophies of Fisher, Neyman-Pearson and Jeffrey are discussed in detail. Descriptive aspects: The misuses of Null Hypothesis Significance Tests are reconsidered in light of Jeffreys’ Bayesian conceptions concerning the role of statistical inference in experimental investigations. Prescriptive aspects: The current effect size and confidence interval reporting practices are presented and seriously questioned. Methodological aspects are carefully discussed and fiducial Bayesian methods are proposed as a more suitable alternative for reporting on experimental results. In closing, basic routine procedures...

  11. The hard-core model on random graphs revisited

    International Nuclear Information System (INIS)

    Barbier, Jean; Krzakala, Florent; Zhang, Pan; Zdeborová, Lenka

    2013-01-01

    We revisit the classical hard-core model, also known as independent set and dual to vertex cover problem, where one puts particles with a first-neighbor hard-core repulsion on the vertices of a random graph. Although the case of random graphs with small and very large average degrees respectively are quite well understood, they yield qualitatively different results and our aim here is to reconciliate these two cases. We revisit results that can be obtained using the (heuristic) cavity method and show that it provides a closed-form conjecture for the exact density of the densest packing on random regular graphs with degree K ≥ 20, and that for K > 16 the nature of the phase transition is the same as for large K. This also shows that the hard-code model is the simplest mean-field lattice model for structural glasses and jamming

  12. Barrier island facies models and recognition criteria

    Science.gov (United States)

    Mulhern, J.; Johnson, C. L.

    2017-12-01

    Barrier island outcrops record transgressive shoreline motion at geologic timescales, providing integral clues to understanding how coastlines respond to rising sea levels. However, barrier island deposits are difficult to recognize. While significant progress has been made in understanding the modern coastal morphodynamics, this insight is not fully leveraged in existing barrier island facies models. Excellent outcrop exposures of the paralic Upper Cretaceous Straight Cliffs Formation of southern Utah provide an opportunity to revise facies models and recognition criteria for barrier island deposits. Preserved barrier islands are composed of three main architectural elements (shorefaces, tidal inlets, and tidal channels) which occur independently or in combination to create larger-scale barrier island deposits. Barrier island shorefaces record progradation, while barrier island tidal inlets record lateral migration, and barrier island tidal channels record aggradation within the tidal inlet. Four facies associations are used to describe and characterize these barrier island architectural elements. Barrier islands occur in association with backarrier fill and internally contain lower and upper shoreface, high-energy upper shoreface, and tidal channel facies. Barrier islands bound lagoons or estuaries, and are distinguished from other shoreface deposits by their internal facies and geometry, association with backbarrier facies, and position within transgressive successions. Tidal processes, in particular tidal inlet migration and reworking of the upper shoreface, also distinguish barrier island deposits. Existing barrier island models highlight the short term heterogeneous and dynamic nature of barrier island systems, yet overlook processes tied to geologic time scales, such as multi-directional motion, erosion, and reworking, and their expressions in preserved barrier island strata. This study uses characteristic outcrop expressions of barrier island successions to

  13. One million served: Rhode Island`s recycling facility

    Energy Technology Data Exchange (ETDEWEB)

    Malloy, M.G.

    1997-11-01

    Rhode Island`s landfill and adjacent materials recovery facility (MRF) in Johnston, both owned by the quasi-public Rhode Island Resource Recovery Corp. (RIRRC, Johnston), serve the entire state. The $12-million recycling facility was built in 1989 next to the state`s sole landfill, the Central Landfill, which accepts only in-state trash. The MRF is operated for RIRRC by New England CRInc. (Hampton, N.H.), a unit of Waste Management, Inc. (WMI, Oak Brook, Ill.). It handles a wide variety of materials, from the usual newspaper, cardboard, and mixed containers to new streams such as wood waste, scrap metal, aseptic packaging (milk and juice boxes), and even textiles. State municipalities are in the process of adding many of these new recyclable streams into their curbside collection programs, all of which feed the facility.

  14. Radiative corrections to neutrino deep inelastic scattering revisited

    International Nuclear Information System (INIS)

    Arbuzov, Andrej B.; Bardin, Dmitry Yu.; Kalinovskaya, Lidia V.

    2005-01-01

    Radiative corrections to neutrino deep inelastic scattering are revisited. One-loop electroweak corrections are re-calculated within the automatic SANC system. Terms with mass singularities are treated including higher order leading logarithmic corrections. Scheme dependence of corrections due to weak interactions is investigated. The results are implemented into the data analysis of the NOMAD experiment. The present theoretical accuracy in description of the process is discussed

  15. The Assassination of John F. Kennedy: Revisiting the Medical Data

    OpenAIRE

    Rohrich, Rod J.; Nagarkar, Purushottam; Stokes, Mike; Weinstein, Aaron; Mantik, David W.; Jensen, J. Arthur

    2014-01-01

    Thank you for publishing "The Assassination of John F. Kennedy: Revisiting the Medical Data."1 The central conclusion of this study is that the assassination remains controversial and that some of the controversy must be attributable to the "reporting and handling of the medical evidence." With the greatest respect for you and Dr. Robert McClelland, let me argue that your text and on-line interviews perpetuate the central misunderstanding of the assassination and there...

  16. Quark matter revisited with non-extensive MIT bag model

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Pedro H.G.; Nunes da Silva, Tiago; Menezes, Debora P. [Universidade Federal de Santa Catarina, Departamento de Fisica, CFM, Florianopolis (Brazil); Deppman, Airton [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

    2017-10-15

    In this work we revisit the MIT bag model to describe quark matter within both the usual Fermi-Dirac and the Tsallis statistics. We verify the effects of the non-additivity of the latter by analysing two different pictures: the first order phase transition of the QCD phase diagram and stellar matter properties. While the QCD phase diagram is visually affected by the Tsallis statistics, the resulting effects on quark star macroscopic properties are barely noticed. (orig.)

  17. Ambulatory thyroidectomy: A multistate study of revisits and complications

    OpenAIRE

    Orosco, RK; Lin, HW; Bhattacharyya, N

    2015-01-01

    © 2015 American Academy of Otolaryngology - Head and Neck Surgery Foundation. Objective. Determine rates and reasons for revisits after ambulatory adult thyroidectomy. Study Design. Cross-sectional analysis of multistate ambulatory surgery and hospital databases. Setting. Ambulatory surgery data from the State Ambulatory Surgery Databases of California, Florida, Iowa, and New York for calendar years 2010 and 2011. Subjects and Methods. Ambulatory thyroidectomy cases were linked to state ambul...

  18. Place attachment and social legitimacy: Revisiting the sustainable entrepreneurship journey

    OpenAIRE

    Kibler, E; Fink, M; Lang, R; Munoz, PA

    2015-01-01

    This paper revisits the sustainable entrepreneurship journey by introducing a ‘place- based’ sustainable venture path model. We suggest that distinguishing between emo- tional (‘caring about the place’) and instrumental (‘using the place’) place attachment of sustainable entrepreneurs deepens our understanding of how place-based challenges of sustainable venture legitimacy are managed over time. We conclude with avenues for future sustainable entrepreneurship research.

  19. Doppler Processing with Ultra-Wideband (UWB) Radar Revisited

    Science.gov (United States)

    2018-01-01

    REPORT TYPE Technical Note 3. DATES COVERED (From - To) December 2017 4. TITLE AND SUBTITLE Doppler Processing with Ultra-Wideband (UWB) Radar...unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT This technical note revisits previous work performed at the US Army Research Laboratory related to...target considered previously is proportional to a delayed version of the transmitted signal, up to a complex constant factor. We write the received

  20. Radiative corrections to double-Dalitz decays revisited

    Science.gov (United States)

    Kampf, Karol; Novotný, Jiři; Sanchez-Puertas, Pablo

    2018-03-01

    In this study, we revisit and complete the full next-to-leading order corrections to pseudoscalar double-Dalitz decays within the soft-photon approximation. Comparing to the previous study, we find small differences, which are nevertheless relevant for extracting information about the pseudoscalar transition form factors. Concerning the latter, these processes could offer the opportunity to test them—for the first time—in their double-virtual regime.

  1. Dispute Resolution and Technology: Revisiting the Justification of Conflict Management

    OpenAIRE

    Koulu, Riikka

    2016-01-01

    This study, Dispute Resolution and Technology: Revisiting the Justification of Conflict Management, belongs to the fields of procedural law, legal theory and law and technology studies. In this study the changes in dispute resolution caused by technology are evaluated. The overarching research question of this study is how does implementing technology to dispute resolution challenge the justification of law as a legitimised mode of violence? Before answering such an abstract research question...

  2. Deja vu: The Unified Command Plan of the Future Revisited

    Science.gov (United States)

    2011-05-19

    Approved for Public Release; Distribution is Unlimited Déjà vu : The Unified Command Plan of the Future Revisited A Monograph by Lieutenant...DD-MM-YYYY) 19-05-2011 2. REPORT TYPE Monograph 3. DATES COVERED (From - To) JUL 2010 – MAY 2011 4. TITLE AND SUBTITLE Déjà vu : The Unified...i SCHOOL OF ADVANCED MILITARY STUDIES MONOGRAPH APPROVAL Lieutenant Colonel Edward Francis Martignetti Title of Monograph: Déjà vu : The Unified

  3. Hospital revisit rate after a diagnosis of conversion disorder.

    Science.gov (United States)

    Merkler, Alexander E; Parikh, Neal S; Chaudhry, Simriti; Chait, Alanna; Allen, Nicole C; Navi, Babak B; Kamel, Hooman

    2016-04-01

    To estimate the hospital revisit rate of patients diagnosed with conversion disorder (CD). Using administrative data, we identified all patients discharged from California, Florida and New York emergency departments (EDs) and acute care hospitals between 2005 and 2011 with a primary discharge diagnosis of CD. Patients discharged with a primary diagnosis of seizure or transient global amnesia (TGA) served as control groups. Our primary outcome was the rate of repeat ED visits and hospital admissions after initial presentation. Poisson regression was used to compare rates between diagnosis groups while adjusting for demographic characteristics. We identified 7946 patients discharged with a primary diagnosis of CD. During a mean follow-up of 3.0 (±1.6) years, patients with CD had a median of three (IQR, 1-9) ED or inpatient revisits, compared with 0 (IQR, 0-2) in patients with TGA and 3 (IQR, 1-7) in those with seizures. Revisit rates were 18.25 (95% CI, 18.10 to 18.40) visits per 100 patients per month in those with CD, 3.90 (95% CI, 3.84 to 3.95) in those with TGA and 17.78 (95% CI, 17.75 to 17.81) in those with seizures. As compared to CD, the incidence rate ratio for repeat ED visits or hospitalisations was 0.89 (95% CI, 0.86 to 0.93) for seizure disorder and 0.32 (95% CI 0.31 to 0.34) for TGA. CD is associated with a substantial hospital revisit rate. Our findings suggest that CD is not an acute, time-limited response to stress, but rather that CD is a manifestation of a broader pattern of chronic neuropsychiatric disease. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  4. Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited

    DEFF Research Database (Denmark)

    Martens, Pernille; Worm, Signe Westring; Lundgren, Bettina

    2004-01-01

    Serotype-specific mortality from invasive Streptococcus pneumoniae disease revisited.Martens P, Worm SW, Lundgren B, Konradsen HB, Benfield T. Department of Infectious Diseases 144, Hvidovre University Hospital, DK-2650 Hvidovre, Denmark. pernillemartens@yahoo.com BACKGROUND: Invasive infection...... with Streptococcus pneumoniae (pneumococci) causes significant morbidity and mortality. Case series and experimental data have shown that the capsular serotype is involved in the pathogenesis and a determinant of disease outcome. METHODS: Retrospective review of 464 cases of invasive disease among adults diagnosed...

  5. Spatially extensive microbial biogeography of the Indian Ocean provides insights into the unique community structure of a pristine coral atoll

    DEFF Research Database (Denmark)

    Jeffries, Thomas C; Ostrowski, Martin; Williams, Rohan B

    2015-01-01

    microbial samples collected in the pristine lagoon of Salomon Islands, Chagos Archipelago. This was the first large-scale ecogenomic survey aboard a private yacht employing a 'citizen oceanography' approach and tools and protocols easily adapted to ocean going sailboats. Our data highlighted biogeographic...

  6. Observations of coupled seismicity and ground deformation at El Hierro Island (2011-2014)

    Science.gov (United States)

    Gonzalez, P. J.

    2015-12-01

    New insights into the magma storage and evolution at oceanic island volcanoes are now being achieved using remotely sensed space geodetic techniques, namely satellite radar interferometry. Differential radar interferometry is a technique tracking, at high spatial resolution, changes in the travel-time (distance) from the satellites to the ground surface, having wide applications in Earth sciences. Volcanic activity usually is accompanied by surface ground deformation. In many instances, modelling of surface deformation has the great advantage to estimate the magma volume change, a particularly interesting parameter prior to eruptions. Jointly interpreted with petrology, degassing and seismicity, it helps to understand the crustal magmatic systems as a whole. Current (and near-future) radar satellite missions will reduce the revisit time over global sub-aerial volcanoes to a sub-weekly basis, which will increase the potential for its operational use. Time series and filtering processing techniques of such streaming data would allow to track subsurface magma migration with high precision, and frequently update over vast areas (volcanic arcs, large caldera systems, etc.). As an example for the future potential monitoring scenario, we analyze multiple satellite radar data over El Hierro Island (Canary Islands, Spain) to measure and model surface ground deformation. El Hierro has been active for more than 3 years (2011 to 2014). Initial phases of the unrest culminated in a submarine eruption (late 2011 - early 2012). However, after the submarine eruption ended, its magmatic system still active and affected by pseudo-regular energetic seismic swarms, accompanied by surface deformation without resumed eruptions. Such example is a great opportunity to understand the crustal magmatic systems in low magma supply-rate oceanic island volcanoes. This new approach to measure surface deformation processes is yielding an ever richer level of information from volcanology to

  7. Terrestrial bird population trends on Aguiguan (Goat Island), Mariana Islands

    Science.gov (United States)

    Amidon, Fred; Camp, Richard J.; Marshall, Ann P.; Pratt, Thane K.; Williams, Laura; Radley, Paul; Cruz, Justine B.

    2014-01-01

    The island of Aguiguan is part of the Mariana archipelago and currently supports populations of four endemic species, including one endemic genus, Cleptornis. Bird population trends since 1982 were recently assessed on the neighbouring islands of Saipan, Tinian, and Rota indicating declines in some native species. Point-transect surveys were conducted in 2008 by the U.S. Fish and Wildlife Service to assess population densities and trends on Aguiguan. Densities for six of the nine native birds—White-throated Ground-dove Gallicolumba xanthonura, Collared Kingfisher Todiramphus chloris, Rufous Fantail Rhipidura rufifrons, Golden White-eye Cleptornis marchei, Bridled White-eye Zosterops conspicillatus and Micronesian Starling Aplonis opaca—and the non-native bird—Island Collared-dove Streptopelia bitorquata—were significantly greater in 2008 than in 1982. No differences in densities were detected among the surveys for Mariana Fruit-dove Ptilinopus roseicapilla, and Micronesian MyzomelaMyzomela rubratra. Three federally and locally listed endangered birds—Nightingale Reed-warbler Acrocephalus luscinius, Mariana Swiftlet Collocalia bartschi, and Micronesian Megapode Megapodius laperous)—were either not detected during the point-transect counts, the surveys were not appropriate for the species, or the numbers of birds detected were too small to estimate densities. The factors behind the increasing trends for some species are unknown but may be related to increased forest cover on the island since 1982. With declining trends for some native species on neighbouring islands, the increasing and stable trends on Aguiguan is good news for forest bird populations in the region, as Aguiguan populations can help support conservation efforts on other islands in the archipelago.

  8. Late Quaternary climate change shapes island biodiversity

    DEFF Research Database (Denmark)

    Weigelt, Patrick; Steinbauer, Manuel; Cabral, Juliano

    2016-01-01

    Island biogeographical models consider islands either as geologically static with biodiversity resulting from ecologically neutral immigration–extinction dynamics1, or as geologically dynamic with biodiversity resulting from immigration–speciation–extinction dynamics influenced by changes in island...... sea levels3, 4 and caused massive changes in island area, isolation and connectivity5, orders of magnitude faster than the geological processes of island formation, subsidence and erosion considered in island theory2, 6. Consequences of these oscillations for present biodiversity remain unassessed5, 7...

  9. Late Quaternary climate change shapes island biodiversity.

    Science.gov (United States)

    Weigelt, Patrick; Steinbauer, Manuel Jonas; Cabral, Juliano Sarmento; Kreft, Holger

    2016-04-07

    Island biogeographical models consider islands either as geologically static with biodiversity resulting from ecologically neutral immigration-extinction dynamics, or as geologically dynamic with biodiversity resulting from immigration-speciation-extinction dynamics influenced by changes in island characteristics over millions of years. Present climate and spatial arrangement of islands, however, are rather exceptional compared to most of the Late Quaternary, which is characterized by recurrent cooler and drier glacial periods. These climatic oscillations over short geological timescales strongly affected sea levels and caused massive changes in island area, isolation and connectivity, orders of magnitude faster than the geological processes of island formation, subsidence and erosion considered in island theory. Consequences of these oscillations for present biodiversity remain unassessed. Here we analyse the effects of present and Last Glacial Maximum (LGM) island area, isolation, elevation and climate on key components of angiosperm diversity on islands worldwide. We find that post-LGM changes in island characteristics, especially in area, have left a strong imprint on present diversity of endemic species. Specifically, the number and proportion of endemic species today is significantly higher on islands that were larger during the LGM. Native species richness, in turn, is mostly determined by present island characteristics. We conclude that an appreciation of Late Quaternary environmental change is essential to understand patterns of island endemism and its underlying evolutionary dynamics.

  10. Greece, Milos Island Geothermal Project

    International Nuclear Information System (INIS)

    Delliou, E.E.

    1990-01-01

    On Milos island (Aegean Sea) a high enthalpy, water dominated geothermal field of high salinity exists. At 1985, a 2MW geothermoelectric pilot plant was installed on the island. This plant has been provided by Mitsubishi Heavy Industries of Japan under a contract with Public Power Corporation of Greece. Due to high salinity of the geothermal fluid, unforeseen problems (scaling mainly) arisen in both steam and brine cycles. As a consequence, the operation (trial mainly) of the power plant have been interrupted several times for long periods, in order to identify the arisen, each time, problems and find the most appropriate technical solution. The above fact, as well as, some unfortunate coincidences described in this paper, led Milos people to react against geothermal development in their island. The sequence of the events, technical and non-technical, their approach and the relevant conclusions are reported in this presentation

  11. Dust Storm Hits Canary Islands

    Science.gov (United States)

    2002-01-01

    A thick pall of sand and dust blew out from the Sahara Desert over the Atlantic Ocean yesterday (January 6, 2002), engulfing the Canary Islands in what has become one of the worst sand storms ever recorded there. In this scene, notice how the dust appears particularly thick in the downwind wake of Tenerife, the largest of the Canary Islands. Perhaps the turbulence generated by the air currents flowing past the island's volcanic peaks is churning the dust back up into the atmosphere, rather than allowing it to settle toward the surface. This true-color image was captured by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite, on January 7, 2002. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  12. Anthropic pressures on Egadi Islands

    International Nuclear Information System (INIS)

    Peronaci, Marcello; Luciani, Roberto

    2015-01-01

    The Egadi Islands, like most Mediterranean islets, have radically changed the traditional lifestyle and the economic development model, based for centuries on the almost self-sufficient resources and production activities, mostly related to the sea (fishing and fish processing) and to the land. During the second half of the 1900., the development of transport radically transformed this model to make smaller islands, at least those closest to the coast, more tightly interconnected and dependent on the mainland. In particular, in Favignana, which is the most populous island and very close to the coast, the traditional activities tourism have led to a strong anthropic pressure concentrated in a few months of the year (summer) on the one hand, and a reduction of the resident population during the winter months on the other, with a serious impact on the care of the land [it

  13. Review of islanding detection methods for distributed generation

    DEFF Research Database (Denmark)

    Chen, Zhe; Mahat, Pukar; Bak-Jensen, Birgitte

    2008-01-01

    This paper presents an overview of power system islanding and islanding detection techniques. Islanding detection techniques, for a distribution system with distributed generation (DG), can broadly be divided into remote and local techniques. A remote islanding detection technique is associated...

  14. HYDROGEOLOGICAL RELATIONS ON KARSTIFIED ISLANDS - VIS ISLAND CASE STUDY

    Directory of Open Access Journals (Sweden)

    Josip Terzić

    2004-12-01

    Full Text Available An approach to the hydrogeological investigations on Adriatic islands is presented on the Island of Vis case study. Infiltration, accumulation and discharge of the groundwater occur in karstified rock mass. Hydrogeological relations are mostly a consequence of the geological setting, because of the complete hydrogeologic barrier in Komiža bay, and relative barrier in the area of karst poljes. Significant research was performed in the 1999 – 2000 period aimed of better understanding of hydrogeological relations. These investigations, as well as reinterpretation of some previously known data, included structural geology, hydrogeology, hydrology and hydrochemistry. Approximate rock mass hydraulic conductivity calculation is also shown, as well as level of its usability in such terrain. Based on all these methods, it is possible to conclude that on the Island of Vis there is no saline water present underneath the entire island. There is only a saline water wedge which is formed on the top of relatively impermeable base rock, some few tens of meters under recent sea level. With such a model, and taking in account the hydrological balance, it is possible to conclude that there is possibility of higher amount of groundwater exploitation then it is today (the paper is published in Croatian.

  15. Obesity and Native Hawaiians/Pacific Islanders

    Science.gov (United States)

    ... Population Profiles > Native Hawaiian/Other Pacific Islander > Obesity Obesity and Native Hawaiians/Pacific Islanders Native Hawaiians/Pacific ... youthonline . [Accessed 08/18/2017] HEALTH IMPACT OF OBESITY People who are overweight are more likely to ...

  16. Submarine physiography off Lakshadweep Islands, Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Chauhan, O.S; Chaubey, A

    Analysis of echosoundings, side scan sonar and shallow seismic data, supplementEd. by 152 sediment samples, collected along 150 km around Lakshadweep Islands, Arabian Sea, revealed that the islands have a very narrow shelf, and an abrupt, shelf...

  17. Benthic Mapping in Long Island Sound

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — QTCView is used with an incorporated depthfinder to create a sonar map of the bottom to the west of the Charles Island, in Long Island Sound in Connecticut waters....

  18. Dredged Material Management in Long Island Sound

    Science.gov (United States)

    Information on Western and Central Long Island Sound Dredged Material Disposal Sites including the Dredged Material Management Plan and Regional Dredging Team. Information regarding the Eastern Long Island Sound Selected Site including public meetings.

  19. Bartolome Island, Galapagos Stable Oxygen Calibration Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Galapagos Coral Stable Oxygen Calibration Data. Sites: Bartolome Island: 0 deg, 17'S, 90 deg 33' W. Champion Island: 1 deg, 15'S, 90 deg, 05' W. Urvina Bay (Isabela...

  20. Asthma and Native Hawaiians/Pacific Islanders

    Science.gov (United States)

    ... Population Profiles > Native Hawaiian/Other Pacific Islander > Asthma Asthma and Native Hawaiians/Pacific Islanders National data for ... very limited. While all of the causes of asthma remain unclear, children exposed to secondhand tobacco smoke ...