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Sample records for strongly typed evolutionary

  1. Evolutionary dynamics with fluctuating population sizes and strong mutualism.

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  2. Evolutionary dynamics with fluctuating population sizes and strong mutualism

    Science.gov (United States)

    Chotibut, Thiparat; Nelson, David R.

    2015-08-01

    Game theory ideas provide a useful framework for studying evolutionary dynamics in a well-mixed environment. This approach, however, typically enforces a strictly fixed overall population size, deemphasizing natural growth processes. We study a competitive Lotka-Volterra model, with number fluctuations, that accounts for natural population growth and encompasses interaction scenarios typical of evolutionary games. We show that, in an appropriate limit, the model describes standard evolutionary games with both genetic drift and overall population size fluctuations. However, there are also regimes where a varying population size can strongly influence the evolutionary dynamics. We focus on the strong mutualism scenario and demonstrate that standard evolutionary game theory fails to describe our simulation results. We then analytically and numerically determine fixation probabilities as well as mean fixation times using matched asymptotic expansions, taking into account the population size degree of freedom. These results elucidate the interplay between population dynamics and evolutionary dynamics in well-mixed systems.

  3. Reduced larval feeding rate is a strong evolutionary correlate of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 85; Issue 3. Reduced larval feeding rate is a strong evolutionary correlate of rapid development in Drosophila melanogaster. M. Rajamani N. Raghavendra ... Keywords. life-history evolution; development time; larval feeding rate; competition; tradeoffs; Drosophila melanogaster.

  4. Reduced larval feeding rate is a strong evolutionary correlate of ...

    Indian Academy of Sciences (India)

    New Delhi 110 054, India; Evolutionary Biology Laboratory, Evolutionary and Organismal Biology Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560 064, India; Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada; Department of Environmental Biology, ...

  5. Evolutionary hypothesis for Chiari type I malformation.

    Science.gov (United States)

    Fernandes, Yvens Barbosa; Ramina, Ricardo; Campos-Herrera, Cynthia Resende; Borges, Guilherme

    2013-10-01

    Chiari I malformation (CM-I) is classically defined as a cerebellar tonsillar herniation (≥5 mm) through the foramen magnum. A decreased posterior fossa volume, mainly due to basioccipital hypoplasia and sometimes platybasia, leads to posterior fossa overcrowding and consequently cerebellar herniation. Regardless of radiological findings, embryological genetic hypothesis or any other postulations, the real cause behind this malformation is yet not well-elucidated and remains largely unknown. The aim of this paper is to approach CM-I under a broader and new perspective, conjoining anthropology, genetics and neurosurgery, with special focus on the substantial changes that have occurred in the posterior cranial base through human evolution. Important evolutionary allometric changes occurred during brain expansion and genetics studies of human evolution demonstrated an unexpected high rate of gene flow interchange and possibly interbreeding during this process. Based upon this review we hypothesize that CM-I may be the result of an evolutionary anthropological imprint, caused by evolving species populations that eventually met each other and mingled in the last 1.7 million years. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Prediction of strong earthquake motions on rock surface using evolutionary process models

    International Nuclear Information System (INIS)

    Kameda, H.; Sugito, M.

    1984-01-01

    Stochastic process models are developed for prediction of strong earthquake motions for engineering design purposes. Earthquake motions with nonstationary frequency content are modeled by using the concept of evolutionary processes. Discussion is focused on the earthquake motions on bed rocks which are important for construction of nuclear power plants in seismic regions. On this basis, two earthquake motion prediction models are developed, one (EMP-IB Model) for prediction with given magnitude and epicentral distance, and the other (EMP-IIB Model) to account for the successive fault ruptures and the site location relative to the fault of great earthquakes. (Author) [pt

  7. Evolutionary origin of type IV classical cadherins in arthropods.

    Science.gov (United States)

    Sasaki, Mizuki; Akiyama-Oda, Yasuko; Oda, Hiroki

    2017-06-17

    Classical cadherins are a metazoan-specific family of homophilic cell-cell adhesion molecules that regulate morphogenesis. Type I and type IV cadherins in this family function at adherens junctions in the major epithelial tissues of vertebrates and insects, respectively, but they have distinct, relatively simple domain organizations that are thought to have evolved by independent reductive changes from an ancestral type III cadherin, which is larger than derived paralogs and has a complicated domain organization. Although both type III and type IV cadherins have been identified in hexapods and branchiopods, the process by which the type IV cadherin evolved is still largely unclear. Through an analysis of arthropod genome sequences, we found that the only classical cadherin encoded in chelicerate genomes was the type III cadherin and that the two type III cadherin genes found in the spider Parasteatoda tepidariorum genome exhibited a complex yet ancestral exon-intron organization in arthropods. Genomic and transcriptomic data from branchiopod, copepod, isopod, amphipod, and decapod crustaceans led us to redefine the type IV cadherin category, which we separated into type IVa and type IVb, which displayed a similar domain organization, except type IVb cadherins have a larger number of extracellular cadherin (EC) domains than do type IVa cadherins (nine versus seven). We also showed that type IVa cadherin genes occurred in the hexapod, branchiopod, and copepod genomes whereas only type IVb cadherin genes were present in malacostracans. Furthermore, comparative characterization of the type IVb cadherins suggested that the presence of two extra EC domains in their N-terminal regions represented primitive characteristics. In addition, we identified an evolutionary loss of two highly conserved cysteine residues among the type IVa cadherins of insects. We provide a genomic perspective of the evolution of classical cadherins among bilaterians, with a focus on the Arthropoda

  8. Strong typing of object-oriented languages revisited

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann; Magnusson, Boris; Møller-Pedersen, Birger

    1990-01-01

    This paper is concerned with the relation between subtyping and subclassing and their influence on programming language design. Traditionally subclassing as introduced by Simula has also been used for defining a hierarchical type system. The type system of a language can be characterized as strong...

  9. Strong phenotypic plasticity limits potential for evolutionary responses to climate change.

    Science.gov (United States)

    Oostra, Vicencio; Saastamoinen, Marjo; Zwaan, Bas J; Wheat, Christopher W

    2018-03-08

    Phenotypic plasticity, the expression of multiple phenotypes from one genome, is a widespread adaptation to short-term environmental fluctuations, but whether it facilitates evolutionary adaptation to climate change remains contentious. Here, we investigate seasonal plasticity and adaptive potential in an Afrotropical butterfly expressing distinct phenotypes in dry and wet seasons. We assess the transcriptional architecture of plasticity in a full-factorial analysis of heritable and environmental effects across 72 individuals, and reveal pervasive gene expression differences between the seasonal phenotypes. Strikingly, intra-population genetic variation for plasticity is largely absent, consistent with specialisation to a particular environmental cue reliably predicting seasonal transitions. Under climate change, deteriorating accuracy of predictive cues will likely aggravate maladaptive phenotype-environment mismatches and increase selective pressures on reaction norms. However, the observed paucity of genetic variation for plasticity limits evolutionary responses, potentially weakening prospects for population persistence. Thus, seasonally plastic species may be especially vulnerable to climate change.

  10. Strong transthyretin immunostaining: potential pitfall in cardiac amyloid typing.

    Science.gov (United States)

    Satoskar, Anjali A; Efebera, Yvonne; Hasan, Ayesha; Brodsky, Sergey; Nadasdy, Gyongyi; Dogan, Ahmet; Nadasdy, Tibor

    2011-11-01

    Although systemic amyloidosis commonly presents with renal disease, cardiac involvement usually determines the patient's prognosis. Cardiac involvement is seen in light chain amyloid and transthyretin amyloidosis. Distinguishing between these two is critical because prognosis and treatment differ. Our study demonstrates the unreliability of transthyretin immunostaining in subtyping cardiac amyloid. Between January 2003 and August 2010, we retrieved 229 native endomyocardial biopsies, of which 24 had amyloid. Immunohistochemistry for κ, λ, transthyretin, and serum amyloid A protein was performed on formalin-fixed, paraffin-embedded sections. Staining was graded as weak (trace to 1+) or strong (2 to 3+). Mass spectrometry (MS)-based proteomic typing of microdissected amyloid material was performed on selected cases. Fifteen patients had monoclonal gammopathy/plasma cell dyscrasia with cardiac amyloid. Eight of them (53%) showed strong transthyretin staining in the cardiac amyloid deposits. MS was performed in 5 of these 8 biopsies, and all 5 biopsies revealed light chain amyloid-type amyloid. Two of these 5 light chain amyloid biopsies did not even have concomitant strong staining for the appropriate light chain. Among the 15 cases with plasma cell dyscrasia, only 7 biopsies showed strong staining for the corresponding monoclonal light chain. Strong, false-positive immunostaining for transthyretin in cardiac amyloid is a potential pitfall, augmented by the frequent lack of staining for immunoglobulin light chains. Therefore, the presence of amyloid in the cardiac biopsy should prompt a search for plasma cell dyscrasia irrespective of transthyretin staining. Confirmation with MS should be sought, particularly if there is any discrepancy between κ/λ staining and serum immunofixation results.

  11. A strong ultraviolet pulse from a newborn type Ia supernova.

    Science.gov (United States)

    Cao, Yi; Kulkarni, S R; Howell, D Andrew; Gal-Yam, Avishay; Kasliwal, Mansi M; Valenti, Stefano; Johansson, J; Amanullah, R; Goobar, A; Sollerman, J; Taddia, F; Horesh, Assaf; Sagiv, Ilan; Cenko, S Bradley; Nugent, Peter E; Arcavi, Iair; Surace, Jason; Woźniak, P R; Moody, Daniela I; Rebbapragada, Umaa D; Bue, Brian D; Gehrels, Neil

    2015-05-21

    Type Ia supernovae are destructive explosions of carbon-oxygen white dwarfs. Although they are used empirically to measure cosmological distances, the nature of their progenitors remains mysterious. One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion. Here we report observations with the Swift Space Telescope of strong but declining ultraviolet emission from a type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star, and therefore provides evidence that some type Ia supernovae arise from the single degenerate channel.

  12. Role of genomic typing in taxonomy, evolutionary genetics, and microbial epidemiology.

    NARCIS (Netherlands)

    Belkum, van A.; Struelens, M.; Visser, de J.A.G.M.; Verburgh, H.; Tibayrenc., M.

    2001-01-01

    Currently, genetic typing of microorganisms is widely used in several major fields of microbiological research. Taxonomy, research aimed at elucidation of evolutionary dynamics or phylogenetic relationships, population genetics of microorganisms, and microbial epidemiology all rely on genetic typing

  13. Role of genomic typing in taxonomy, evolutionary genetics, and microbial epidemiology.

    NARCIS (Netherlands)

    A.F. van Belkum (Alex); M. Struelens; A. de Visser (Arjan); H.A. Verbrugh (Henri); M. Tibayrench

    2001-01-01

    textabstractCurrently, genetic typing of microorganisms is widely used in several major fields of microbiological research. Taxonomy, research aimed at elucidation of evolutionary dynamics or phylogenetic relationships, population genetics of microorganisms, and

  14. Role of Genomic Typing in Taxonomy, Evolutionary Genetics, and Microbial Epidemiology

    OpenAIRE

    van Belkum, Alex; Struelens, Marc; de Visser, Arjan; Verbrugh, Henri; Tibayrenc, Michel

    2001-01-01

    Currently, genetic typing of microorganisms is widely used in several major fields of microbiological research. Taxonomy, research aimed at elucidation of evolutionary dynamics or phylogenetic relationships, population genetics of microorganisms, and microbial epidemiology all rely on genetic typing data for discrimination between genotypes. Apart from being an essential component of these fundamental sciences, microbial typing clearly affects several areas of applied microbiogical research. ...

  15. Role of genomic typing in taxonomy, evolutionary genetics, and microbial epidemiology.

    OpenAIRE

    Belkum, Alex; Struelens, M.; Visser, Arjan; Verbrugh, Henri; Tibayrench, M.

    2001-01-01

    textabstractCurrently, genetic typing of microorganisms is widely used in several major fields of microbiological research. Taxonomy, research aimed at elucidation of evolutionary dynamics or phylogenetic relationships, population genetics of microorganisms, and microbial epidemiology all rely on genetic typing data for discrimination between genotypes. Apart from being an essential component of these fundamental sciences, microbial typing clearly affects several areas of applied microbiologi...

  16. Strong association between myotonic dystrophy type 2 and autoimmune diseases.

    NARCIS (Netherlands)

    Tieleman, A.A.; Broeder, A. den; Logt, A. van de; Engelen, B.G.M. van

    2009-01-01

    BACKGROUND: Myotonic dystrophy type 2 (DM2) is a dominantly inherited multisystem disorder, characterised by progressive proximal weakness, myotonia, cataracts and cardiac conduction abnormalities. Our clinical impression of an association between DM2 and autoimmune diseases or autoantibody

  17. Cavity types and microclimate: implications for ecological, evolutionary, and conservation studies.

    Science.gov (United States)

    Amat-Valero, M; Calero-Torralbo, M A; Václav, R; Valera, F

    2014-11-01

    The abiotic conditions of the immediate environment of organisms are key factors for a better understanding of ecological and evolutionary processes. Yet, information in this regard is biased towards some habitat types, landscapes, and organisms. Here, we present a 2-year comparative study of the microclimatic properties (temperature, relative humidity, and their fluctuation) of three cavity types (nest boxes, cavities in bridges, and burrows in sandy cliffs) in an arid environment. We found marked and consistent months-long differences in microclimate among the three cavity types. Nest boxes were colder than the other cavity types, with temperature oscillations being an order of magnitude higher than in other cavity types. In contrast, microclimate was very stable in burrows and cavities in bridges, the former being generally warmer and drier than the latter. We also discuss the biological implications of microclimatic conditions and its variation in different cavity types by presenting two case studies, namely the temperature-humidity index and water vapor pressure during the hatching period of an endotherm and the chilling period during the diapause of an ectotherm ectoparasite. We stress the need for comparative studies of the same organisms subjected to different microclimates given the important ecological, evolutionary, and conservation implications.

  18. Relationship Between Personality Types on the Strong-Campbell and Myers-Briggs Instruments.

    Science.gov (United States)

    Dillon, Michael; Weissman, Shel

    1987-01-01

    Examined relationship between Holland's personality types as measured by the Strong-Campbell Interest Inventory and Jung's personality types as measured by the Myers-Briggs Type Indicator. College students' (N=394) responses to the two instruments revealed significant associations between certain types based on interests and preferences.…

  19. CRF19_cpx is an Evolutionary fit HIV-1 Variant Strongly Associated With Rapid Progression to AIDS in Cuba.

    Science.gov (United States)

    Kouri, Vivian; Khouri, Ricardo; Alemán, Yoan; Abrahantes, Yeissel; Vercauteren, Jurgen; Pineda-Peña, Andrea-Clemencia; Theys, Kristof; Megens, Sarah; Moutschen, Michel; Pfeifer, Nico; Van Weyenbergh, Johan; Pérez, Ana B; Pérez, Jorge; Pérez, Lissette; Van Laethem, Kristel; Vandamme, Anne-Mieke

    2015-03-01

    Clinicians reported an increasing trend of rapid progression (RP) (AIDS within 3 years of infection) in Cuba. Recently infected patients were prospectively sampled, 52 RP at AIDS diagnosis (AIDS-RP) and 21 without AIDS in the same time frame (non-AIDS). 22 patients were sampled at AIDS diagnosis (chronic-AIDS) retrospectively assessed as > 3 years infected. Clinical, demographic, virological, epidemiological and immunological data were collected. Pol and env sequences were used for subtyping, transmission cluster analysis, and prediction of resistance, co-receptor use and evolutionary fitness. Host, immunological and viral predictors of RP were explored through data mining. Subtyping revealed 26 subtype B strains, 6 C, 6 CRF18_cpx, 9 CRF19_cpx, 29 BG-recombinants and other subtypes/URFs. All patients infected with CRF19 belonged to the AIDS-RP group. Data mining identified CRF19, oral candidiasis and RANTES levels as the strongest predictors of AIDS-RP. CRF19 was more frequently predicted to use the CXCR4 co-receptor, had higher fitness scores in the protease region, and patients had higher viral load at diagnosis. CRF19 is a recombinant of subtype D (C-part of Gag, PR, RT and nef), subtype A (N-part of Gag, Integrase, Env) and subtype G (Vif, Vpr, Vpu and C-part of Env). Since subtypes D and A have been associated with respectively faster and slower disease progression, our findings might indicate a fit PR driving high viral load, which in combination with co-infections may boost RANTES levels and thus CXCR4 use, potentially explaining the fast progression. We propose that CRF19 is evolutionary very fit and causing rapid progression to AIDS in many newly infected patients in Cuba.

  20. Role of Genomic Typing in Taxonomy, Evolutionary Genetics, and Microbial Epidemiology

    Science.gov (United States)

    van Belkum, Alex; Struelens, Marc; de Visser, Arjan; Verbrugh, Henri; Tibayrenc, Michel

    2001-01-01

    Currently, genetic typing of microorganisms is widely used in several major fields of microbiological research. Taxonomy, research aimed at elucidation of evolutionary dynamics or phylogenetic relationships, population genetics of microorganisms, and microbial epidemiology all rely on genetic typing data for discrimination between genotypes. Apart from being an essential component of these fundamental sciences, microbial typing clearly affects several areas of applied microbiogical research. The epidemiological investigation of outbreaks of infectious diseases and the measurement of genetic diversity in relation to relevant biological properties such as pathogenicity, drug resistance, and biodegradation capacities are obvious examples. The diversity among nucleic acid molecules provides the basic information for all fields described above. However, researchers in various disciplines tend to use different vocabularies, a wide variety of different experimental methods to monitor genetic variation, and sometimes widely differing modes of data processing and interpretation. The aim of the present review is to summarize the technological and fundamental concepts used in microbial taxonomy, evolutionary genetics, and epidemiology. Information on the nomenclature used in the different fields of research is provided, descriptions of the diverse genetic typing procedures are presented, and examples of both conceptual and technological research developments for Escherichia coli are included. Recommendations for unification of the different fields through standardization of laboratory techniques are made. PMID:11432813

  1. Deciphering evolutionary strata on plant sex chromosomes and fungal mating-type chromosomes through compositional segmentation.

    Science.gov (United States)

    Pandey, Ravi S; Azad, Rajeev K

    2016-03-01

    Sex chromosomes have evolved from a pair of homologous autosomes which differentiated into sex determination systems, such as XY or ZW system, as a consequence of successive recombination suppression between the gametologous chromosomes. Identifying the regions of recombination suppression, namely, the "evolutionary strata", is central to understanding the history and dynamics of sex chromosome evolution. Evolution of sex chromosomes as a consequence of serial recombination suppressions is well-studied for mammals and birds, but not for plants, although 48 dioecious plants have already been reported. Only two plants Silene latifolia and papaya have been studied until now for the presence of evolutionary strata on their X chromosomes, made possible by the sequencing of sex-linked genes on both the X and Y chromosomes, which is a requirement of all current methods that determine stratum structure based on the comparison of gametologous sex chromosomes. To circumvent this limitation and detect strata even if only the sequence of sex chromosome in the homogametic sex (i.e. X or Z chromosome) is available, we have developed an integrated segmentation and clustering method. In application to gene sequences on the papaya X chromosome and protein-coding sequences on the S. latifolia X chromosome, our method could decipher all known evolutionary strata, as reported by previous studies. Our method, after validating on known strata on the papaya and S. latifolia X chromosome, was applied to the chromosome 19 of Populus trichocarpa, an incipient sex chromosome, deciphering two, yet unknown, evolutionary strata. In addition, we applied this approach to the recently sequenced sex chromosome V of the brown alga Ectocarpus sp. that has a haploid sex determination system (UV system) recovering the sex determining and pseudoautosomal regions, and then to the mating-type chromosomes of an anther-smut fungus Microbotryum lychnidis-dioicae predicting five strata in the non

  2. Structural and evolutionary aspects of algal blue light receptors of the cryptochrome and aureochrome type.

    Science.gov (United States)

    Essen, Lars-Oliver; Franz, Sophie; Banerjee, Ankan

    2017-10-01

    Blue-light reception plays a pivotal role for algae to adapt to changing environmental conditions. In this review we summarize the current structural and mechanistic knowledge about flavin-dependent algal photoreceptors. We especially focus on the cryptochrome and aureochrome type photoreceptors in the context of their evolutionary divergence. Despite similar photochemical characteristics to orthologous photoreceptors from higher plants and animals the algal blue-light photoreceptors have developed a set of unique structural and mechanistic features that are summarized below. Copyright © 2017 Elsevier GmbH. All rights reserved.

  3. Physical Properties and Evolutionary States of EA-type Eclipsing Binaries Observed by LAMOST

    Science.gov (United States)

    Qian, S.-B.; Zhang, J.; He, J.-J.; Zhu, L.-Y.; Zhao, E.-G.; Shi, X.-D.; Zhou, X.; Han, Z.-T.

    2018-03-01

    About 3196 EA-type binaries (EAs) were observed by LAMOST by 2017 June 16 and their spectral types were derived. Meanwhile, the stellar atmospheric parameters of 2020 EAs were determined. In this paper, those EAs are cataloged and their physical properties and evolutionary states are investigated. The period distribution of EAs suggests that the period limit of tidal locking for the close binaries is about 6 days. It is found that the metallicity of EAs is higher than that of EW-type binaries (EWs), indicating that EAs are generally younger than EWs and they are the progenitors of EWs. The metallicities of long-period EWs (0.4values of Log (g) are usually smaller than those of EAs. These support the evolutionary process that EAs evolve into long-period EWs through the combination of angular momentum loss (AML) via magnetic braking and case A mass transfer. For short-period EWs, their metallicities are lower than those of EAs, while their gravitational accelerations are higher. These reveal that they may be formed from cool short-period EAs through AML via magnetic braking with little mass transfer. For some EWs with high metallicities, they may be contaminated by material from the evolution of unseen neutron stars and black holes or they have third bodies that may help them to form rapidly through a short timescale of pre-contact evolution. The present investigation suggests that the modern EW populations may have formed through a combination of these mechanisms.

  4. Krasnoselskii-type algorithm for zeros of strongly monotone Lipschitz maps in classical banach spaces.

    Science.gov (United States)

    Chidume, C E; Bello, A U; Usman, B

    2015-01-01

    Let [Formula: see text], [Formula: see text], and [Formula: see text] be a strongly monotone and Lipschitz mapping. A Krasnoselskii-type sequence is constructed and proved to converge strongly to the unique solution of [Formula: see text]. Furthermore, our technique of proo f is of independent interest.

  5. Evolutionary Analysis of MIKCc-Type MADS-Box Genes in Gymnosperms and Angiosperms

    Directory of Open Access Journals (Sweden)

    Fei Chen

    2017-05-01

    Full Text Available MIKCc-type MADS-box genes encode transcription factors that control floral organ morphogenesis and flowering time in flowering plants. Here, in order to determine when the subfamilies of MIKCc originated and their early evolutionary trajectory, we sampled and analyzed the genomes and large-scale transcriptomes representing all the orders of gymnosperms and basal angiosperms. Through phylogenetic inference, the MIKCc-type MADS-box genes were subdivided into 14 monophyletic clades. Among them, the gymnosperm orthologs of AGL6, SEP, AP1, GMADS, SOC1, AGL32, AP3/PI, SVP, AGL15, ANR1, and AG were identified. We identified and characterized the origin of a novel subfamily GMADS within gymnosperms but lost orthologs in monocots and Brassicaceae. ABCE model prototype genes were relatively conserved in terms of gene number in gymnosperms, but expanded in angiosperms, whereas SVP, SOC1, and GMADS had dramatic expansions in gymnosperms but conserved in angiosperms. Our results provided the most detailed evolutionary history of all MIKCc gene clades in gymnosperms and angiosperms. We proposed that although the near complete set of MIKCc genes had evolved in gymnosperms, the duplication and expressional transition of ABCE model MIKCc genes in the ancestor of angiosperms triggered the first flower.

  6. Evolutionary Analysis of MIKCc-Type MADS-Box Genes in Gymnosperms and Angiosperms

    Science.gov (United States)

    Chen, Fei; Zhang, Xingtan; Liu, Xing; Zhang, Liangsheng

    2017-01-01

    MIKCc-type MADS-box genes encode transcription factors that control floral organ morphogenesis and flowering time in flowering plants. Here, in order to determine when the subfamilies of MIKCc originated and their early evolutionary trajectory, we sampled and analyzed the genomes and large-scale transcriptomes representing all the orders of gymnosperms and basal angiosperms. Through phylogenetic inference, the MIKCc-type MADS-box genes were subdivided into 14 monophyletic clades. Among them, the gymnosperm orthologs of AGL6, SEP, AP1, GMADS, SOC1, AGL32, AP3/PI, SVP, AGL15, ANR1, and AG were identified. We identified and characterized the origin of a novel subfamily GMADS within gymnosperms but lost orthologs in monocots and Brassicaceae. ABCE model prototype genes were relatively conserved in terms of gene number in gymnosperms, but expanded in angiosperms, whereas SVP, SOC1, and GMADS had dramatic expansions in gymnosperms but conserved in angiosperms. Our results provided the most detailed evolutionary history of all MIKCc gene clades in gymnosperms and angiosperms. We proposed that although the near complete set of MIKCc genes had evolved in gymnosperms, the duplication and expressional transition of ABCE model MIKCc genes in the ancestor of angiosperms triggered the first flower. PMID:28611810

  7. Evolutionary Dynamics of Mating-Type Loci of Mycosphaerella spp. Occurring on Banana▿ †

    Science.gov (United States)

    Arzanlou, Mahdi; Crous, Pedro W.; Zwiers, Lute-Harm

    2010-01-01

    The devastating Sigatoka disease complex of banana is primarily caused by three closely related heterothallic fungi belonging to the genus Mycosphaerella: M. fijiensis, M. musicola, and M. eumusae. Previous phylogenetic work showing common ancestry led us to analyze the mating-type loci of these Mycosphaerella species occurring on banana. We reasoned that this might provide better insight into the evolutionary history of these species. PCR and chromosome-walking approaches were used to clone the mating-type loci of M. musicola and M. eumusae. Sequences were compared to the published mating-type loci of M. fijiensis and other Mycosphaerella spp., and a novel organization of the MAT loci was found. The mating-type loci of the examined Mycosphaerella species are expanded, containing two additional Mycosphaerella-specific genes in a unique genomic organization. The proteins encoded by these novel genes show a higher interspecies than intraspecies homology. Moreover, M. fijiensis, M. musicola, and M. eumusae contain two additional mating-type-like loci, containing parts of both MAT1-1-1 and MAT1-2-1. The data indicate that M. fijiensis, M. musicola, and M. eumusae share an ancestor in which a fusion event occurred between MAT1-1-1 and MAT1-2-1 sequences and in which additional genes became incorporated into the idiomorph. The new genes incorporated have since then evolved independently in the MAT1-1 and MAT1-2 loci. Thus, these data are an example of the evolutionary dynamics of fungal MAT loci in general and show the great flexibility of the MAT loci of Mycosphaerella species in particular. PMID:19915079

  8. Evolutionary dynamics of mating-type loci of Mycosphaerella spp. occurring on banana.

    Science.gov (United States)

    Arzanlou, Mahdi; Crous, Pedro W; Zwiers, Lute-Harm

    2010-01-01

    The devastating Sigatoka disease complex of banana is primarily caused by three closely related heterothallic fungi belonging to the genus Mycosphaerella: M. fijiensis, M. musicola, and M. eumusae. Previous phylogenetic work showing common ancestry led us to analyze the mating-type loci of these Mycosphaerella species occurring on banana. We reasoned that this might provide better insight into the evolutionary history of these species. PCR and chromosome-walking approaches were used to clone the mating-type loci of M. musicola and M. eumusae. Sequences were compared to the published mating-type loci of M. fijiensis and other Mycosphaerella spp., and a novel organization of the MAT loci was found. The mating-type loci of the examined Mycosphaerella species are expanded, containing two additional Mycosphaerella-specific genes in a unique genomic organization. The proteins encoded by these novel genes show a higher interspecies than intraspecies homology. Moreover, M. fijiensis, M. musicola, and M. eumusae contain two additional mating-type-like loci, containing parts of both MAT1-1-1 and MAT1-2-1. The data indicate that M. fijiensis, M. musicola, and M. eumusae share an ancestor in which a fusion event occurred between MAT1-1-1 and MAT1-2-1 sequences and in which additional genes became incorporated into the idiomorph. The new genes incorporated have since then evolved independently in the MAT1-1 and MAT1-2 loci. Thus, these data are an example of the evolutionary dynamics of fungal MAT loci in general and show the great flexibility of the MAT loci of Mycosphaerella species in particular.

  9. Function and Evolutionary Origin of Unicellular Camera-Type Eye Structure

    KAUST Repository

    Hayakawa, Shiho

    2015-03-03

    The ocelloid is an extraordinary eyespot organelle found only in the dinoflagellate family Warnowiaceae. It contains retina- and lens-like structures called the retinal body and the hyalosome. The ocelloid has been an evolutionary enigma because of its remarkable resemblance to the multicellular camera-type eye. To determine if the ocelloid is functionally photoreceptive, we investigated the warnowiid dinoflagellate Erythropsidinium. Here, we show that the morphology of the retinal body changed depending on different illumination conditions and the hyalosome manifests the refractile nature. Identifying a rhodopsin gene fragment in Erythropsidinium ESTs that is expressed in the retinal body by in situ hybridization, we also show that ocelloids are actually light sensitive photoreceptors. The rhodopsin gene identified is most closely related to bacterial rhodopsins. Taken together, we suggest that the ocelloid is an intracellular camera-type eye, which might be originated from endosymbiotic origin. © 2015 Hayakawa et al.

  10. Strong Normalization by Type-Directed Partial Evaluation and Run-Time Code Generation

    DEFF Research Database (Denmark)

    Balat, Vincent; Danvy, Olivier

    1997-01-01

    We investigate the synergy between type-directed partial evaluation and run-time code generation for the Caml dialect of ML. Type-directed partial evaluation maps simply typed, closed Caml values to a representation of their long βη-normal form. Caml uses a virtual machine and has the capability...... conclude this note with a preview of our current work on scaling up strong normalization by run-time code generation to the Caml module language....

  11. Strong normalization by type-directed partial evaluation and run-time code generation

    DEFF Research Database (Denmark)

    Balat, Vincent; Danvy, Olivier

    1998-01-01

    We investigate the synergy between type-directed partial evaluation and run-time code generation for the Caml dialect of ML. Type-directed partial evaluation maps simply typed, closed Caml values to a representation of their long βη-normal form. Caml uses a virtual machine and has the capability...... conclude this note with a preview of our current work on scaling up strong normalization by run-time code generation to the Caml module language....

  12. Pollen morphology of the dichapetalaceae with special reference to evolutionary trends and mutual relationships of pollen types

    NARCIS (Netherlands)

    Punt, W.

    Pollen grains of all three genera of Dichapetalaceae (Dichapetalum, Stephanopodium and Tapura) comprising about 150 species have been studied. Twenty-nine pollen types were recognized and the family has to be considered eurypalynous. A key to the pollen types is added. Based on evolutionary trends

  13. Browder's type strong convergence theorems for infinite families of nonexpansive mappings in Banach spaces

    Directory of Open Access Journals (Sweden)

    Suzuki Tomonari

    2006-01-01

    Full Text Available We prove Browder's type strong convergence theorems for infinite families of nonexpansive mappings. One of our main results is the following: let be a bounded closed convex subset of a uniformly smooth Banach space . Let be an infinite family of commuting nonexpansive mappings on . Let and be sequences in satisfying for . Fix and define a sequence in by for . Then converges strongly to , where is the unique sunny nonexpansive retraction from onto .

  14. Dark matter distributions in early-type galaxies from strong gravitational lensing

    International Nuclear Information System (INIS)

    Eichner, Thomas Martin

    2013-01-01

    Dark matter constitutes a large fraction of the mass of early-type galaxies. However, the exact amount and spatial distribution of the dark matter, especially in the galaxies' center is still unclear. Furthermore, galaxies in dense environments such as the centers of galaxy clusters shrink in size, since parts of their outer dark matter halo is stripped away. The aim of this thesis is to measure the dark matter content in the centers and outskirts of elliptical galaxies by analyzing the strong gravitational lensing effect they produce. Gravitational lensing is well-suited for investigating dark matter, since it is sensitive to all forms of matter, regardless of its dynamical or evolutionary state. We present gravitational lensing studies of the exceptional strong lensing systems SDSS J1538+5817 and SDSS J1430+4105, identified by the Sloan Lens ACS survey. The lenses are elliptical galaxies at z l =0.143 and z l =0.285, respectively. For SDSS J1538+5817 we show that both multiple imaged sources are located at the same redshift z s =0.531. Its multiple images span a range from 1 to 4 kpc in the plane of the lens. For SDSS J1430+4105, the source at redshift z s =0.575 is imaged into a broad Einstein ring, covering radii from 4 kpc to 10 kpc in the plane of the lens. In both cases, the lensed images can be accurately and consistently reproduced with different modeling approaches. We get projected total masses of 8.11 +0.27 -0.59 x 10 10 M s un within the Einstein radius of 2.5 kpc for SDSS J1538+5817 and 5.37±0.06 x 10 11 M s un within 6.5 kpc for SDSS J1430+4105. The luminous and dark matter were traced separately, resulting in dark matter fractions within the Einstein radius of 0.1 +0.2 -0.1 and 0.40 +0.14 -0.10 for SDSS J1538+5817 and SDSS J1430+4105, respectively. We assume a de Vaucouleurs profile to trace the light distribution of both galaxies. From the stellar mass associated with this light, we can explicitly derive a stellar mass-to-light ratio of (M de

  15. Probing Evolutionary Population Synthesis Models in the Near Infrared with Early Type Galaxies

    Science.gov (United States)

    Dahmer-Hahn, Luis Gabriel; Riffel, Rogério; Rodríguez-Ardila, Alberto; Martins, Lucimara P.; Kehrig, Carolina; Heckman, Timothy M.; Pastoriza, Miriani G.; Dametto, Natacha Z.

    2018-02-01

    We performed a near-infrared (NIR, ˜1.0μm-2.4μm) stellar population study in a sample of early type galaxies. The synthesis was performed using five different evolutionary population synthesis libraries of models. Our main results can be summarized as follows: low spectral resolution libraries are not able to produce reliable results when applied to the NIR alone, with each library finding a different dominant population. The two newest higher resolution models, on the other hand, perform considerably better, finding consistent results to each other and to literature values. We also found that optical results are consistent with each other even for lower resolution models. We also compared optical and NIR results, and found out that lower resolution models tend to disagree in the optical and in the NIR, with higher fraction of young populations in the NIR and dust extinction ˜1 magnitude higher than optical values. For higher resolution models, optical and NIR results tend do aggree much better, suggesting that a higher spectral resolution is fundamental to improve the quality of the results.

  16. Body composition and susceptibility to type 2 diabetes: an evolutionary perspective.

    Science.gov (United States)

    Wells, J C K

    2017-07-01

    Type 2 diabetes is rapidly increasing in prevalence worldwide, in concert with epidemics of obesity and sedentary behavior that are themselves tracking economic development. Within this broad pattern, susceptibility to diabetes varies substantially in association with ethnicity and nutritional exposures through the life-course. An evolutionary perspective may help understand why humans are so prone to this condition in modern environments, and why this risk is unequally distributed. A simple conceptual model treats diabetes risk as the function of two interacting traits, namely 'metabolic capacity' which promotes glucose homeostasis, and 'metabolic load' which challenges glucose homoeostasis. This conceptual model helps understand how long-term and more recent trends in body composition can be considered to have shaped variability in diabetes risk. Hominin evolution appears to have continued a broader trend evident in primates, towards lower levels of muscularity. In addition, hominins developed higher levels of body fatness, especially in females in relative terms. These traits most likely evolved as part of a broader reorganization of human life history traits in response to growing levels of ecological instability, enabling both survival during tough periods and reproduction during bountiful periods. Since the emergence of Homo sapiens, populations have diverged in body composition in association with geographical setting and local ecological stresses. These long-term trends in both metabolic capacity and adiposity help explain the overall susceptibility of humans to diabetes in ways that are similar to, and exacerbated by, the effects of nutritional exposures during the life-course.

  17. The ecological and evolutionary implications of merging different types of networks

    NARCIS (Netherlands)

    Fontaine, C.; Guimaraes, P.R.; Kefi, S.; Loeuille, N.; Memmott, J.; Van der Putten, W.H.; Van Veen, F.J.F.; Thebault, E.

    2011-01-01

    Interactions among species drive the ecological and evolutionary processes in ecological communities. These interactions are effectively key components of biodiversity. Studies that use a network approach to study the structure and dynamics of communities of interacting species have revealed many

  18. An angiotensin II type 1 receptor activation switch patch revealed through evolutionary trace analysis

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Yao, Rong; Ma, Jian-Nong

    2010-01-01

    ) displayed phenotypes associated with changed activation state, such as increased agonist affinity or basal activity, promiscuous activation, or constitutive internalization highlighting the importance of testing different signaling pathways. We conclude that this evolutionary important patch mediates...

  19. Evolutionary restoration of fertility in an interspecies hybrid yeast, by whole-genome duplication after a failed mating-type switch.

    Directory of Open Access Journals (Sweden)

    Raúl A Ortiz-Merino

    2017-05-01

    Full Text Available Many interspecies hybrids have been discovered in yeasts, but most of these hybrids are asexual and can replicate only mitotically. Whole-genome duplication has been proposed as a mechanism by which interspecies hybrids can regain fertility, restoring their ability to perform meiosis and sporulate. Here, we show that this process occurred naturally during the evolution of Zygosaccharomyces parabailii, an interspecies hybrid that was formed by mating between 2 parents that differed by 7% in genome sequence and by many interchromosomal rearrangements. Surprisingly, Z. parabailii has a full sexual cycle and is genetically haploid. It goes through mating-type switching and autodiploidization, followed by immediate sporulation. We identified the key evolutionary event that enabled Z. parabailii to regain fertility, which was breakage of 1 of the 2 homeologous copies of the mating-type (MAT locus in the hybrid, resulting in a chromosomal rearrangement and irreparable damage to 1 MAT locus. This rearrangement was caused by HO endonuclease, which normally functions in mating-type switching. With 1 copy of MAT inactivated, the interspecies hybrid now behaves as a haploid. Our results provide the first demonstration that MAT locus damage is a naturally occurring evolutionary mechanism for whole-genome duplication and restoration of fertility to interspecies hybrids. The events that occurred in Z. parabailii strongly resemble those postulated to have caused ancient whole-genome duplication in an ancestor of Saccharomyces cerevisiae.

  20. BGK-type models in strong reaction and kinetic chemical equilibrium regimes

    International Nuclear Information System (INIS)

    Monaco, R; Bianchi, M Pandolfi; Soares, A J

    2005-01-01

    A BGK-type procedure is applied to multi-component gases undergoing chemical reactions of bimolecular type. The relaxation process towards local Maxwellians, depending on mass and numerical densities of each species as well as common velocity and temperature, is investigated in two different cases with respect to chemical regimes. These cases are related to the strong reaction regime characterized by slow reactions, and to the kinetic chemical equilibrium regime where fast reactions take place. The consistency properties of both models are stated in detail. The trend to equilibrium is numerically tested and comparisons for the two regimes are performed within the hydrogen-air and carbon-oxygen reaction mechanism. In the spatial homogeneous case, it is also shown that the thermodynamical equilibrium of the models recovers satisfactorily the asymptotic equilibrium solutions to the reactive Euler equations

  1. Evolutionary thinking

    Science.gov (United States)

    Hunt, Tam

    2014-01-01

    Evolution as an idea has a lengthy history, even though the idea of evolution is generally associated with Darwin today. Rebecca Stott provides an engaging and thoughtful overview of this history of evolutionary thinking in her 2013 book, Darwin's Ghosts: The Secret History of Evolution. Since Darwin, the debate over evolution—both how it takes place and, in a long war of words with religiously-oriented thinkers, whether it takes place—has been sustained and heated. A growing share of this debate is now devoted to examining how evolutionary thinking affects areas outside of biology. How do our lives change when we recognize that all is in flux? What can we learn about life more generally if we study change instead of stasis? Carter Phipps’ book, Evolutionaries: Unlocking the Spiritual and Cultural Potential of Science's Greatest Idea, delves deep into this relatively new development. Phipps generally takes as a given the validity of the Modern Synthesis of evolutionary biology. His story takes us into, as the subtitle suggests, the spiritual and cultural implications of evolutionary thinking. Can religion and evolution be reconciled? Can evolutionary thinking lead to a new type of spirituality? Is our culture already being changed in ways that we don't realize by evolutionary thinking? These are all important questions and Phipps book is a great introduction to this discussion. Phipps is an author, journalist, and contributor to the emerging “integral” or “evolutionary” cultural movement that combines the insights of Integral Philosophy, evolutionary science, developmental psychology, and the social sciences. He has served as the Executive Editor of EnlightenNext magazine (no longer published) and more recently is the co-founder of the Institute for Cultural Evolution, a public policy think tank addressing the cultural roots of America's political challenges. What follows is an email interview with Phipps. PMID:26478766

  2. Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors

    Science.gov (United States)

    Willa, R.; Koshelev, A. E.; Sadovskyy, I. A.; Glatz, A.

    2018-01-01

    The current-carrying capacity of type-II superconductors is decisively determined by how well material defect structures can immobilize vortex lines. In order to gain deeper insights into the fundamental pinning mechanisms, we have explored the case of vortex trapping by randomly distributed spherical inclusions using large-scale simulations of the time-dependent Ginzburg–Landau equations. We find that for a small density of particles having diameters of two coherence lengths, the vortex lattice preserves its structure and the critical current j c decays with the magnetic field following a power-law {B}-α with α ≈ 0.66, which is consistent with predictions of strong-pinning theory. For a higher density of particles and/or larger inclusions, the lattice becomes progressively more disordered and the exponent smoothly decreases down to α ≈ 0.3. At high magnetic fields, all inclusions capture a vortex and the critical current decays faster than {B}-1 as would be expected by theory. In the case of larger inclusions with a diameter of four coherence lengths, the magnetic-field dependence of the critical current is strongly affected by the ability of inclusions to capture multiple vortex lines. We found that at small densities, the fraction of inclusions trapping two vortex lines rapidly grows within narrow field range leading to a peak in j c(B)-dependence within this range. With increasing inclusion density, this peak transforms into a plateau, which then smooths out. Using the insights gained from simulations, we determine the limits of applicability of strong-pinning theory and provide different routes to describe vortex pinning beyond those bounds.

  3. Strong-pinning regimes by spherical inclusions in anisotropic type-II superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Willa, R.; Koshelev, A. E.; Sadovskyy, I. A.; Glatz, A.

    2017-11-27

    The current-carrying capacity of type-II superconductors is decisively determined by how well material defect structures can immobilize vortex lines. In order to gain deeper insights into intrinsic pinning mechanisms, we have explored the case of vortex trapping by randomly distributed spherical inclusions using large-scale simulations of the time-dependent Ginzburg-Landau equations. We find that for a small density of particles having diameters of two coherence lengths, the vortex lattice preserves its structure and the critical current jc decays with the magnetic field following a power-law B-a with a ~ 0:66, which is consistent with predictions of strong pinning theory. For higher density of particles and/or larger inclusions, the lattice becomes progressively more disordered and the exponent smoothly decreases down to a ~ 0:3. At high magnetic fields, all inclusions capture a vortex and the critical current decays faster than B-1 as would be expected by theory. In the case of larger inclusions with diameter of four coherence length, the magnetic-field dependence of the critical current is strongly affected by the ability of inclusions to capture multiple vortex lines. We found that at small densities, the fraction of inclusions trapping two vortex lines rapidly grows within narrow field range leading to a shallow peak in jc(B)-dependence within this range. With increasing inclusion density, this peak transforms into a plateau, which then smooths out. Using the insights gained from simulations, we determine the limits of applicability of strong pinning theory and provide different routes to describe vortex pinning beyond those bounds.

  4. Evolutionary macroecology

    Directory of Open Access Journals (Sweden)

    José Alexandre F. Diniz-Filho

    2013-10-01

    Full Text Available Macroecology focuses on ecological questions at broad spatial and temporal scales, providing a statistical description of patterns in species abundance, distribution and diversity. More recently, historical components of these patterns have begun to be investigated more deeply. We tentatively refer to the practice of explicitly taking species history into account, both analytically and conceptually, as ‘evolutionary macroecology’. We discuss how the evolutionary dimension can be incorporated into macroecology through two orthogonal and complementary data types: fossils and phylogenies. Research traditions dealing with these data have developed more‐or‐less independently over the last 20–30 years, but merging them will help elucidate the historical components of diversity gradients and the evolutionary dynamics of species’ traits. Here we highlight conceptual and methodological advances in merging these two research traditions and review the viewpoints and toolboxes that can, in combination, help address patterns and unveil processes at temporal and spatial macro‐scales.

  5. Phase separation in strongly correlated electron systems with two types of charge carriers

    International Nuclear Information System (INIS)

    Kugel, K.I.; Rakhmanov, A.L.; Sboychakov, A.O.

    2007-01-01

    Full text: A competition between the localization of the charge carriers due to Jahn-Teller distortions and the energy gain due to their delocalization in doped manganite and related magnetic oxides is analyzed based on a Kondo-lattice type model. The resulting effective Hamiltonian is, in fact, a generalization of the Falicov-Kimball model. We find that the number of itinerant charge carriers can be significantly lower than that implied by the doping level x. The phase diagram of the model in the T plane is constructed. The system exhibits magnetic ordered (antiferromagnetic, ferromagnetic, or canted) states as well the paramagnetic states with zero and nonzero density of the itinerant electrons. It is shown that a phase-separation is favorable in energy for a wide doping range. The characteristic size of inhomogeneities in a phase-separated state is of the order of several lattice constants. We also analyzed the two-band Hubbard model in the limit of strong on-site Coulomb repulsion. It was shown that such a system has a tendency to phase separation into the regions with different charge densities even in the absence of magnetic or any other ordering, if the ratio of the bandwidths is large enough. The work was supported by the European project CoMePhS and by the Russian Foundation for Basic Research, project no. 05-02-17600. (authors)

  6. CENTRAL DARK MATTER TRENDS IN EARLY-TYPE GALAXIES FROM STRONG LENSING, DYNAMICS, AND STELLAR POPULATIONS

    International Nuclear Information System (INIS)

    Tortora, C.; Jetzer, P.; Napolitano, N. R.; Romanowsky, A. J.

    2010-01-01

    We analyze the correlations between central dark matter (DM) content of early-type galaxies and their sizes and ages, using a sample of intermediate-redshift (z ∼ 0.2) gravitational lenses from the SLACS survey, and by comparing them to a larger sample of z ∼ 0 galaxies. We decompose the deprojected galaxy masses into DM and stellar components using combinations of strong lensing, stellar dynamics, and stellar populations modeling. For a given stellar mass, we find that for galaxies with larger sizes, the DM fraction increases and the mean DM density decreases, consistently with the cuspy halos expected in cosmological formation scenarios. The DM fraction also decreases with stellar age, which can be partially explained by the inverse correlation between size and age. The residual trend may point to systematic dependencies on formation epoch of halo contraction or stellar initial mass functions. These results are in agreement with recent findings based on local galaxies by Napolitano et al. and suggest negligible evidence of galaxy evolution over the last ∼2.5 Gyr other than passive stellar aging.

  7. Automatic Creation of Machine Learning Workflows with Strongly Typed Genetic Programming

    Czech Academy of Sciences Publication Activity Database

    Křen, T.; Pilát, M.; Neruda, Roman

    2017-01-01

    Roč. 26, č. 5 (2017), č. článku 1760020. ISSN 0218-2130 R&D Projects: GA ČR GA15-19877S Grant - others:GA MŠk(CZ) LM2015042 Institutional support: RVO:67985807 Keywords : genetic programming * machine learning workflows * asynchronous evolutionary algorithm Subject RIV: IN - Informatics, Computer Science OBOR OECD: Computer sciences, information science, bioinformathics (hardware development to be 2.2, social aspect to be 5.8) Impact factor: 0.778, year: 2016

  8. Effects of Joint Interpretation of the Strong Interest Inventory and the Myers-Briggs Type Indicator in Career Choice.

    Science.gov (United States)

    Katz, Louise; Joyner, John W.; Seaman, Nancy

    1999-01-01

    Students completed either the Strong Interest Inventory (n=114) or Myers-Briggs Type Indicator (n=108), both (n=99), or none (n=106). Twelve weeks after interpretation, those who completed both showed more change, specificity, or certainty in their career goal. The Myers-Briggs proved as helpful as Strong in career decision making. (SK)

  9. Accurate and balanced anisotropic Gaussian type orbital basis sets for atoms in strong magnetic fields

    Science.gov (United States)

    Zhu, Wuming; Trickey, S. B.

    2017-12-01

    In high magnetic field calculations, anisotropic Gaussian type orbital (AGTO) basis functions are capable of reconciling the competing demands of the spherically symmetric Coulombic interaction and cylindrical magnetic (B field) confinement. However, the best available a priori procedure for composing highly accurate AGTO sets for atoms in a strong B field [W. Zhu et al., Phys. Rev. A 90, 022504 (2014)] yields very large basis sets. Their size is problematical for use in any calculation with unfavorable computational cost scaling. Here we provide an alternative constructive procedure. It is based upon analysis of the underlying physics of atoms in B fields that allow identification of several principles for the construction of AGTO basis sets. Aided by numerical optimization and parameter fitting, followed by fine tuning of fitting parameters, we devise formulae for generating accurate AGTO basis sets in an arbitrary B field. For the hydrogen iso-electronic sequence, a set depends on B field strength, nuclear charge, and orbital quantum numbers. For multi-electron systems, the basis set formulae also include adjustment to account for orbital occupations. Tests of the new basis sets for atoms H through C (1 ≤ Z ≤ 6) and ions Li+, Be+, and B+, in a wide B field range (0 ≤ B ≤ 2000 a.u.), show an accuracy better than a few μhartree for single-electron systems and a few hundredths to a few mHs for multi-electron atoms. The relative errors are similar for different atoms and ions in a large B field range, from a few to a couple of tens of millionths, thereby confirming rather uniform accuracy across the nuclear charge Z and B field strength values. Residual basis set errors are two to three orders of magnitude smaller than the electronic correlation energies in multi-electron atoms, a signal of the usefulness of the new AGTO basis sets in correlated wavefunction or density functional calculations for atomic and molecular systems in an external strong B field.

  10. Accurate and balanced anisotropic Gaussian type orbital basis sets for atoms in strong magnetic fields.

    Science.gov (United States)

    Zhu, Wuming; Trickey, S B

    2017-12-28

    In high magnetic field calculations, anisotropic Gaussian type orbital (AGTO) basis functions are capable of reconciling the competing demands of the spherically symmetric Coulombic interaction and cylindrical magnetic (B field) confinement. However, the best available a priori procedure for composing highly accurate AGTO sets for atoms in a strong B field [W. Zhu et al., Phys. Rev. A 90, 022504 (2014)] yields very large basis sets. Their size is problematical for use in any calculation with unfavorable computational cost scaling. Here we provide an alternative constructive procedure. It is based upon analysis of the underlying physics of atoms in B fields that allow identification of several principles for the construction of AGTO basis sets. Aided by numerical optimization and parameter fitting, followed by fine tuning of fitting parameters, we devise formulae for generating accurate AGTO basis sets in an arbitrary B field. For the hydrogen iso-electronic sequence, a set depends on B field strength, nuclear charge, and orbital quantum numbers. For multi-electron systems, the basis set formulae also include adjustment to account for orbital occupations. Tests of the new basis sets for atoms H through C (1 ≤ Z ≤ 6) and ions Li + , Be + , and B + , in a wide B field range (0 ≤ B ≤ 2000 a.u.), show an accuracy better than a few μhartree for single-electron systems and a few hundredths to a few mHs for multi-electron atoms. The relative errors are similar for different atoms and ions in a large B field range, from a few to a couple of tens of millionths, thereby confirming rather uniform accuracy across the nuclear charge Z and B field strength values. Residual basis set errors are two to three orders of magnitude smaller than the electronic correlation energies in multi-electron atoms, a signal of the usefulness of the new AGTO basis sets in correlated wavefunction or density functional calculations for atomic and molecular systems in an external strong B

  11. Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

    Science.gov (United States)

    Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.; Collett, Thomas E.

    2018-03-01

    Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ∼2 over previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Accounting for microlensing, the 1–2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.

  12. Evolution of growth habit, inflorescence architecture, flower size, and fruit type in Rubiaceae: its ecological and evolutionary implications.

    Directory of Open Access Journals (Sweden)

    Sylvain G Razafimandimbison

    Full Text Available During angiosperm evolution, innovations in vegetative and reproductive organs have resulted in tremendous morphological diversity, which has played a crucial role in the ecological success of flowering plants. Morindeae (Rubiaceae display considerable diversity in growth form, inflorescence architecture, flower size, and fruit type. Lianescent habit, head inflorescence, small flower, and multiple fruit are the predominant states, but arborescent habit, non-headed inflorescence, large flower, and simple fruit states occur in various genera. This makes Morindeae an ideal model for exploring the evolutionary appearances and transitions between the states of these characters. We reconstructed ancestral states for these four traits using a bayesian approach and combined nuclear/chloroplast data for 61 Morindeae species. The aim was to test three hypotheses: 1 self-supporting habit is generally ancestral in clades comprising both lianescent and arborescent species; 2 changes from lianescent to arborescent habit are uncommon due to "a high degree of specialization and developmental burden"; 3 head inflorescences and multiple fruits in Morindeae evolved from non-headed inflorescences and simple fruits, respectively. Lianescent habit, head inflorescence, large flower, and multiple fruit are inferred for Morindeae, making arborescent habit, non-headed inflorescence, small flower, and simple fruit derived within the tribe. The rate of change from lianescent to arborescent habit is much higher than the reverse change. Therefore, evolutionary changes between lianescent and arborescent forms can be reversible, and their frequency and trends vary between groups. Moreover, these changes are partly attributed to a scarcity of host trees for climbing plants in more open habitats. Changes from large to small flowers might have been driven by shifts to pollinators with progressively shorter proboscis, which are associated with shifts in breeding systems towards

  13. Symbiotic virus at the evolutionary intersection of three types of large DNA viruses; iridoviruses, ascoviruses, and ichnoviruses.

    Directory of Open Access Journals (Sweden)

    Yves Bigot

    Full Text Available BACKGROUND: The ascovirus, DpAV4a (family Ascoviridae, is a symbiotic virus that markedly increases the fitness of its vector, the parasitic ichneumonid wasp, Diadromus puchellus, by increasing survival of wasp eggs and larvae in their lepidopteran host, Acrolepiopsis assectella. Previous phylogenetic studies have indicated that DpAV4a is related to the pathogenic ascoviruses, such as the Spodoptera frugiperda ascovirus 1a (SfAV1a and the lepidopteran iridovirus (family Iridoviridae, Chilo iridescent virus (CIV, and is also likely related to the ancestral source of certain ichnoviruses (family Polydnaviridae. METHODOLOGY/PRINCIPAL FINDINGS: To clarify the evolutionary relationships of these large double-stranded DNA viruses, we sequenced the genome of DpAV4a and undertook phylogenetic analyses of the above viruses and others, including iridoviruses pathogenic to vertebrates. The DpAV4a genome consisted of 119,343 bp and contained at least 119 open reading frames (ORFs, the analysis of which confirmed the relatedness of this virus to iridoviruses and other ascoviruses. CONCLUSIONS: Analyses of core DpAV4a genes confirmed that ascoviruses and iridoviruses are evolutionary related. Nevertheless, our results suggested that the symbiotic DpAV4a had a separate origin in the iridoviruses from the pathogenic ascoviruses, and that these two types shared parallel evolutionary paths, which converged with respect to virion structure (icosahedral to bacilliform, genome configuration (linear to circular, and cytopathology (plasmalemma blebbing to virion-containing vesicles. Our analyses also revealed that DpAV4a shared more core genes with CIV than with other ascoviruses and iridoviruses, providing additional evidence that DpAV4a represents a separate lineage. Given the differences in the biology of the various iridoviruses and ascoviruses studied, these results provide an interesting model for how viruses of different families evolved from one another.

  14. The evolutionary trajectory of the mating-type (mat genes in Neurospora relates to reproductive behavior of taxa

    Directory of Open Access Journals (Sweden)

    Johannesson Hanna

    2008-04-01

    Full Text Available Abstract Background Comparative sequencing studies among a wide range of taxonomic groups, including fungi, have led to the discovery that reproductive genes evolve more rapidly than other genes. However, for fungal reproductive genes the question has remained whether the rapid evolution is a result of stochastic or deterministic processes. The mating-type (mat genes constitute the master regulators of sexual reproduction in filamentous ascomycetes and here we present a study of the molecular evolution of the four mat-genes (mat a-1, mat A-1, mat A-2 and mat A-3 of 20 Neurospora taxa. Results We estimated nonsynonymous and synonymous substitution rates of genes to infer their evolutionary rate, and confirmed that the mat-genes evolve rapidly. Furthermore, the evolutionary trajectories are related to the reproductive modes of the taxa; likelihood methods revealed that positive selection acting on specific codons drives the diversity in heterothallic taxa, while among homothallic taxa the rapid evolution is due to a lack of selective constraint. The latter finding is supported by presence of stop codons and frame shift mutations disrupting the open reading frames of mat a-1, mat A-2 and mat A-3 in homothallic taxa. Lower selective constraints of mat-genes was found among homothallic than heterothallic taxa, and comparisons with non-reproductive genes argue that this disparity is not a nonspecific, genome-wide phenomenon. Conclusion Our data show that the mat-genes evolve rapidly in Neurospora. The rapid divergence is due to either adaptive evolution or lack of selective constraints, depending on the reproductive mode of the taxa. This is the first instance of positive selection acting on reproductive genes in the fungal kingdom, and illustrates how the evolutionary trajectory of reproductive genes can change after a switch in reproductive behaviour of an organism.

  15. The wild type as concept and in experimental practice: A history of its role in classical genetics and evolutionary theory.

    Science.gov (United States)

    Holmes, Tarquin

    2017-06-01

    Wild types in genetics are specialised strains of laboratory experimental organism which principally serve as standards against which variation is measured. As selectively inbred lineages highly isolated from ancestral wild populations, there appears to be little wild or typical about them. I will nonetheless argue that they have historically been successfully used as stand-ins for nature, allowing knowledge produced in the laboratory to be extrapolated to the natural world. In this paper, I will explore the 19th century origins of the wild type concept, the theoretical and experimental innovations which allowed concepts and organisms to move from wild nature to laboratory domestication c. 1900 (resulting in the production of standardised lab strains), and the conflict among early geneticists between interactionist and atomist accounts of wild type, which would eventually lead to the conceptual disintegration of wild types and the triumph of genocentrism and population genetics. I conclude by discussing how the strategy of using wild type strains to represent nature in the lab has nonetheless survived the downfall of the wild type concept and continues to provide, significant limitations acknowledged, an epistemically productive means of investigating heredity and evolutionary variation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Internalin profiling and multilocus sequence typing suggest four Listeria innocua subgroups with different evolutionary distances from Listeria monocytogenes.

    Science.gov (United States)

    Chen, Jianshun; Chen, Qiaomiao; Jiang, Lingli; Cheng, Changyong; Bai, Fan; Wang, Jun; Mo, Fan; Fang, Weihuan

    2010-03-31

    Ecological, biochemical and genetic resemblance as well as clear differences of virulence between L. monocytogenes and L. innocua make this bacterial clade attractive as a model to examine evolution of pathogenicity. This study was attempted to examine the population structure of L. innocua and the microevolution in the L. innocua-L. monocytogenes clade via profiling of 37 internalin genes and multilocus sequence typing based on the sequences of 9 unlinked genes gyrB, sigB, dapE, hisJ, ribC, purM, gap, tuf and betL. L. innocua was genetically monophyletic compared to L. monocytogenes, and comprised four subgroups. Subgroups A and B correlated with internalin types 1 and 3 (except the strain 0063 belonging to subgroup C) and internalin types 2 and 4 respectively. The majority of L. innocua strains belonged to these two subgroups. Subgroup A harbored a whole set of L. monocytogenes-L. innocua common and L. innocua-specific internalin genes, and displayed higher recombination rates than those of subgroup B, including the relative frequency of occurrence of recombination versus mutation (rho/theta) and the relative effect of recombination versus point mutation (r/m). Subgroup A also exhibited a significantly smaller exterior/interior branch length ratio than expected under the coalescent model, suggesting a recent expansion of its population size. The phylogram based on the analysis with correction for recombination revealed that the time to the most recent common ancestor (TMRCA) of L. innocua subgroups A and B were similar. Additionally, subgroup D, which correlated with internalin type 5, branched off from the other three subgroups. All L. innocua strains lacked seventeen virulence genes found in L. monocytogenes (except for the subgroup D strain L43 harboring inlJ and two subgroup B strains bearing bsh) and were nonpathogenic to mice. L. innocua represents a young species descending from L. monocytogenes and comprises four subgroups: two major subgroups A and B

  17. Internalin profiling and multilocus sequence typing suggest four Listeria innocua subgroups with different evolutionary distances from Listeria monocytogenes

    Directory of Open Access Journals (Sweden)

    Wang Jun

    2010-03-01

    Full Text Available Abstract Background Ecological, biochemical and genetic resemblance as well as clear differences of virulence between L. monocytogenes and L. innocua make this bacterial clade attractive as a model to examine evolution of pathogenicity. This study was attempted to examine the population structure of L. innocua and the microevolution in the L. innocua-L. monocytogenes clade via profiling of 37 internalin genes and multilocus sequence typing based on the sequences of 9 unlinked genes gyrB, sigB, dapE, hisJ, ribC, purM, gap, tuf and betL. Results L. innocua was genetically monophyletic compared to L. monocytogenes, and comprised four subgroups. Subgroups A and B correlated with internalin types 1 and 3 (except the strain 0063 belonging to subgroup C and internalin types 2 and 4 respectively. The majority of L. innocua strains belonged to these two subgroups. Subgroup A harbored a whole set of L. monocytogenes-L. innocua common and L. innocua-specific internalin genes, and displayed higher recombination rates than those of subgroup B, including the relative frequency of occurrence of recombination versus mutation (ρ/θ and the relative effect of recombination versus point mutation (r/m. Subgroup A also exhibited a significantly smaller exterior/interior branch length ratio than expected under the coalescent model, suggesting a recent expansion of its population size. The phylogram based on the analysis with correction for recombination revealed that the time to the most recent common ancestor (TMRCA of L. innocua subgroups A and B were similar. Additionally, subgroup D, which correlated with internalin type 5, branched off from the other three subgroups. All L. innocua strains lacked seventeen virulence genes found in L. monocytogenes (except for the subgroup D strain L43 harboring inlJ and two subgroup B strains bearing bsh and were nonpathogenic to mice. Conclusions L. innocua represents a young species descending from L. monocytogenes and

  18. Ruminant globin gene structures suggest an evolutionary role for Alu-type repeats.

    OpenAIRE

    Schimenti, J C; Duncan, C H

    1984-01-01

    Bovine fetal and adult globin genes were cloned and subjected to DNA sequence analysis. Both of these genes contained insertions of Alu-type repetitive DNA within their introns. Comparison of cow and goat beta-type globin genes indicates that intragenic DNA insertions played a role in their evolution. These data support the theory that Alu-type repeats maintain genetic diversity by inhibiting gene conversion.

  19. Functional and evolutionary studies of type I MADS box genes in Petunia hybrida and arabidopsis thaliana

    NARCIS (Netherlands)

    Bemer, Marian

    2008-01-01

    MADS-box genes are very important for plant development and especially for the formation of the flower. The MADS box family of transcription factors in plants can be subdivided into two classes: the MIKC-type genes, which play essential roles in flower formation, and the type I genes, which are

  20. Gene genealogies indicates abundant gene conversions and independent evolutionary histories of the mating-type chromosomes in the evolutionary history of Neurospora tetrasperma

    Directory of Open Access Journals (Sweden)

    Whittle Carrie A

    2010-07-01

    Full Text Available Abstract Background The self-fertile filamentous ascomycete Neurospora tetrasperma contains a large (~7 Mbp and young (mat chromosomes. The objective of the present study is to reveal the evolutionary history, including key genomic events, associated with the various regions of the mat chromosomes among ten strains representing all the nine known species (lineages contained within the N. tetrasperma species complex. Results Comparative analysis of sequence divergence among alleles of 24 mat-linked genes (mat A and mat a indicates that a large region of suppressed recombination exists within the mat chromosome for each of nine lineages of N. tetrasperma sensu latu. The recombinationally suppressed region varies in size and gene composition among lineages, and is flanked on both ends by normally recombining regions. Genealogical analyses among lineages reveals that eight gene conversion events have occurred between homologous mat A and mat a-linked alleles of genes located within the region of restricted recombination during the evolutionary history of N. tetrasperma. Conclusions We conclude that the region of suppressed recombination in the mat chromosomes has likely been subjected to independent contraction and/or expansion during the evolutionary history of the N. tetrasperma species complex. Furthermore, we infer that gene conversion events are likely a common phenomenon within this recombinationally suppressed genomic region. We argue that gene conversions might provide an efficient mechanism of adaptive editing of functional genes, including the removal of deleterious mutations, within the young recombinationally suppressed region of the mat chromosomes.

  1. Departures from predicted type II behavior in dirty strong-coupling superconductors

    International Nuclear Information System (INIS)

    Park, J.C.; Neighbor, J.E.; Shiffman, C.A.

    1976-01-01

    Calorimetric measurements of the Ginsburg-Landau parameters for Pb-Sn and Pb-Bi alloys show good agreement with the calculations of Rainer and Bergmann for kappa 1 (t)/kappa 1 (1). However, the calculations of Rainer and Usadel for kappa 2 (t)/kappa 2 (1) substantially underestimate the enhancements due to strong-coupling. (Auth.)

  2. Ancestral acquisitions, gene flow and multiple evolutionary trajectories of the type three secretion system and effectors in Xanthomonas plant pathogens.

    Science.gov (United States)

    Merda, Déborah; Briand, Martial; Bosis, Eran; Rousseau, Céline; Portier, Perrine; Barret, Matthieu; Jacques, Marie-Agnès; Fischer-Le Saux, Marion

    2017-11-01

    Deciphering the evolutionary history and transmission patterns of virulence determinants is necessary to understand the emergence of novel pathogens. The main virulence determinant of most pathogenic proteobacteria is the type three secretion system (T3SS). The Xanthomonas genus includes bacteria responsible for numerous epidemics in agroecosystems worldwide and represents a major threat to plant health. The main virulence factor of Xanthomonas is the Hrp2 family T3SS; however, this system is not conserved in all strains and it has not been previously determined whether the distribution of T3SS in this bacterial genus has resulted from losses or independent acquisitions. Based on comparative genomics of 82 genome sequences representing the diversity of the genus, we have inferred three ancestral acquisitions of the Hrp2 cluster during Xanthomonas evolution followed by subsequent losses in some commensal strains and re-acquisition in some species. While mutation was the main force driving polymorphism at the gene level, interspecies homologous recombination of large fragments expanding through several genes shaped Hrp2 cluster polymorphism. Horizontal gene transfer of the entire Hrp2 cluster also occurred. A reduced core effectome composed of xopF1, xopM, avrBs2 and xopR was identified that may allow commensal strains overcoming plant basal immunity. In contrast, stepwise accumulation of numerous type 3 effector genes was shown in successful pathogens responsible for epidemics. Our data suggest that capacity to intimately interact with plants through T3SS would be an ancestral trait of xanthomonads. Since its acquisition, T3SS has experienced a highly dynamic evolutionary history characterized by intense gene flux between species that may reflect its role in host adaptation. © 2017 John Wiley & Sons Ltd.

  3. Novel Type II and Monomeric NAD+ Specific Isocitrate Dehydrogenases: Phylogenetic Affinity, Enzymatic Characterization, and Evolutionary Implication

    OpenAIRE

    Wang, Peng; Lv, Changqi; Zhu, Guoping

    2015-01-01

    NAD+ use is an ancestral trait of isocitrate dehydrogenase (IDH), and the NADP+ phenotype arose through evolution as an ancient adaptation event. However, no NAD+-specific IDHs have been found among type II IDHs and monomeric IDHs. In this study, novel type II homodimeric NAD-IDHs from Ostreococcus lucimarinus CCE9901 IDH (OlIDH) and Micromonas sp. RCC299 (MiIDH), and novel monomeric NAD-IDHs from Campylobacter sp. FOBRC14 IDH (CaIDH) and Campylobacter curvus (CcIDH) were reported for the fir...

  4. An Angiotensin II type 1 receptor activation switch patch revealed through Evolutionary Trace analysis

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Yao, Rong; Ma, Jian-Nong

    2010-01-01

    in the cytoplasmic parts of TM2, TM3, and TM6 to form an activation switch that is common to all family A 7TM receptors. We tested this hypothesis in the rat Angiotensin II (Ang II) type 1a (AT1a) receptor. The receptor has important roles in the cardiovascular system, but has also frequently been applied as a model...

  5. Evolutionary dynamics of mating-type loci of Mycosphaerella spp. occurring on banana

    NARCIS (Netherlands)

    Arzanlou, M.; Crous, P.W.; Zwiers, L.H.

    2010-01-01

    The devastating Sigatoka disease complex of banana is primarily caused by three closely related heterothallic fungi belonging to the genus Mycosphaerella: M. fijiensis, M. musicola, and M. eumusae. Previous phylogenetic work showing common ancestry led us to analyze the mating-type loci of these

  6. An evolutionary perspective on C-type lectins in infection and immunity

    NARCIS (Netherlands)

    van den Berg, Linda M.; Gringhuis, Sonja I.; Geijtenbeek, Teunis B. H.

    2012-01-01

    Host-pathogen interactions have coevolved formany years. On the one hand, the human immune system consists of innate and adaptive immune cells that function to defeat pathogens, and on the other hand, pathogens have coevolved to use the system for their own propagation. C-type lectins are conserved

  7. BSC-1 growth inhibitor/type beta transforming growth factor is a strong inhibitor of thymocyte proliferation.

    OpenAIRE

    Ristow, H J

    1986-01-01

    Growth inhibitor/type beta transforming growth factor purified from BSC-1 cells and human platelets is shown to strongly inhibit the proliferation of Con A-stimulated mouse thymocytes. The inhibition can be achieved with growth inhibitor/type beta transforming growth factor concentrations approximately equal to 1/10th those necessary to inhibit keratinocyte cultures. The inhibitory effect in thymocyte cultures can be reversed by the addition of interleukin 2. These findings suggest that growt...

  8. Experimental triple-slit interference in a strongly driven V-type artificial atom

    Science.gov (United States)

    Dada, Adetunmise C.; Santana, Ted S.; Koutroumanis, Antonios; Ma, Yong; Park, Suk-In; Song, Jindong; Gerardot, Brian D.

    2017-08-01

    Rabi oscillations of a two-level atom appear as a quantum interference effect between the amplitudes associated with atomic superpositions, in analogy with the classic double-slit experiment which manifests a sinusoidal interference pattern. By extension, through direct detection of time-resolved resonance fluorescence from a quantum-dot neutral exciton driven in the Rabi regime, we experimentally demonstrate triple-slit-type quantum interference via quantum erasure in a V-type three-level artificial atom. This result is of fundamental interest in the experimental studies of the properties of V-type three-level systems and may pave the way for further insight into their coherence properties as well as applications for quantum information schemes. It also suggests quantum dots as candidates for multipath-interference experiments for probing foundational concepts in quantum physics.

  9. Diabetic Retinopathy Is Strongly Predictive of Cardiovascular Autonomic Neuropathy in Type 2 Diabetes.

    Science.gov (United States)

    Huang, Chih-Cheng; Lee, Jong-Jer; Lin, Tsu-Kung; Tsai, Nai-Wen; Huang, Chi-Ren; Chen, Shu-Fang; Lu, Cheng-Hsien; Liu, Rue-Tsuan

    2016-01-01

    A well-established, comprehensive, and simple test battery was used here to re-evaluate risk factors for cardiovascular autonomic neuropathy (CAN) in type 2 diabetes. One hundred and seventy-four patients with type 2 diabetes were evaluated through the methods of deep breathing and Valsalva maneuver for correlation with factors that might influence the presence and severity of CAN. The Composite Autonomic Scoring Scale (CASS) was used to grade the severity of autonomic impairment, and CAN was defined as a CASS score ≥2. Results showed that nephropathy, duration of diabetes, blood pressure, uric acid, and the presence of retinopathy and metabolic syndrome significantly correlated with the CASS score. Age may not be a risk factor for diabetic CAN. However, the effects of diabetes on CAN are more prominent in younger patients than in older ones. Diabetic retinopathy is the most significant risk factor predictive of the presence of CAN in patients with type 2 diabetes.

  10. Strongly increasing solutions of cyclic systems of second order differential equations with power-type nonlinearities

    Directory of Open Access Journals (Sweden)

    Jaroslav Jaroš

    2015-01-01

    Full Text Available We consider \\(n\\-dimensional cyclic systems of second order differential equations \\[(p_i(t|x_{i}'|^{\\alpha_i -1}x_{i}'' = q_{i}(t|x_{i+1}|^{\\beta_i-1}x_{i+1},\\] \\[\\quad i = 1,\\ldots,n, \\quad (x_{n+1} = x_1 \\tag{\\(\\ast\\}\\] under the assumption that the positive constants \\(\\alpha_i\\ and \\(\\beta_i\\ satisfy \\(\\alpha_1{\\ldots}\\alpha_n \\gt \\beta_1{\\ldots}\\beta_n\\ and \\(p_i(t\\ and \\(q_i(t\\ are regularly varying functions, and analyze positive strongly increasing solutions of system (\\(\\ast\\ in the framework of regular variation. We show that the situation for the existence of regularly varying solutions of positive indices for (\\(\\ast\\ can be characterized completely, and moreover that the asymptotic behavior of such solutions is governed by the unique formula describing their order of growth precisely. We give examples demonstrating that the main results for (\\(\\ast\\ can be applied to some classes of partial differential equations with radial symmetry to acquire accurate information about the existence and the asymptotic behavior of their radial positive strongly increasing solutions.

  11. Multilocus sequence typing reveals two evolutionary lineages of Acidovorax avenae subsp. citrulli.

    Science.gov (United States)

    Feng, Jianjun; Schuenzel, Erin L; Li, Jianqiang; Schaad, Norman W

    2009-08-01

    Acidovorax avenae subsp. citrulli, causal agent of bacterial fruit blotch, has caused considerable damage to the watermelon and melon industry in China and the United States. Understanding the emergence and spread of this pathogen is important for controlling the disease. To build a fingerprinting database for reliable identification and tracking of strains of A. avenae subsp. citrulli, a multilocus sequence typing (MLST) scheme was developed using seven conserved loci. The study included 8 original strains from the 1978 description of A. avenae subsp. citrulli, 51 from China, and 34 from worldwide collections. Two major clonal complexes (CCs), CC1 and CC2, were identified within A. avenae subsp. citrulli; 48 strains typed as CC1 and 45 as CC2. All eight original 1978 strains isolated from watermelon and melon grouped in CC1. CC2 strains were predominant in the worldwide collection and all but five were isolated from watermelon. In China, a major seed producer for melon and watermelon, the predominant strains were CC1 and were found nearly equally on melon and watermelon.

  12. Gross proteinuria is a strong risk predictor for cardiovascular mortality in Brazilian type 2 diabetic patients

    OpenAIRE

    Cardoso, C.R.L.; Salles, G.F.

    2008-01-01

    Increased proteinuria is recognized as a risk predictor for all-cause and cardiovascular mortality in diabetic patients; however, no study has evaluated these relationships in Brazilian patients. The aim of this study was to investigate the prognostic value of gross proteinuria for all-cause and cardiovascular mortalities and for cardiovascular morbidity in a cohort study of 471 type 2 diabetic individuals followed for up to 7 years. Several clinical, laboratory and electrocardiographic varia...

  13. Hybridization in the Ensatina Ring Species, Strong selection against hybrids at a hybrid zone in the ensatina ring species complex and its evolutionary implications

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrino, Joao; Baird, Stuart J.E.; Lawson, Lucinda; Macey, J. Robert; Moritz, Craig; Wake, David B.

    2005-04-22

    The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders Ensatina eschscholtzii xanthoptica and Ensatina eschscholtzii platensis hybridize in the Central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was re-sampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: (i) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730m to 2000m; (ii) cline centers at the northern Calaveras transect were coincident between 1981 and 2001, demonstrating repeatability over 5 generations; (iii) there are very few if any putative F1's, but a relatively high number of backcrossed individuals (57-86 percent) in the central portion of transects; (iv) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit show maximum values near the center of the zones (R and Fis, approx. equal to 0.5). Using estimates of cline width and dispersal, we infer strong selection against hybrids (s* approx. equal to 46-75 percent). This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of adaptive alleles. The evidence for strong, but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent

  14. The early-type strong emission-line supergiants of the Magellanic Clouds - A spectroscopic zoology

    Science.gov (United States)

    Shore, S. N.; Sanduleak, N.

    1984-01-01

    The results of a spectroscopic survey of 21 early-type extreme emission line supergiants of the Large and Small Magellanic Clouds using IUE and optical spectra are presented. The combined observations are discussed and the literature on each star in the sample is summarized. The classification procedures and the methods by which effective temperatures, bolometric magnitudes, and reddenings were assigned are discussed. The derived reddening values are given along with some results concerning anomalous reddening among the sample stars. The derived mass, luminosity, and radius for each star are presented, and the ultraviolet emission lines are described. Mass-loss rates are derived and discussed, and the implications of these observations for the evolution of the most massive stars in the Local Group are addressed.

  15. Fuzzy-logic modeling of Fenton's strong chemical oxidation process treating three types of landfill leachates.

    Science.gov (United States)

    Sari, Hanife; Yetilmezsoy, Kaan; Ilhan, Fatih; Yazici, Senem; Kurt, Ugur; Apaydin, Omer

    2013-06-01

    Three multiple input and multiple output-type fuzzy-logic-based models were developed as an artificial intelligence-based approach to model a novel integrated process (UF-IER-EDBM-FO) consisted of ultrafiltration (UF), ion exchange resins (IER), electrodialysis with bipolar membrane (EDBM), and Fenton's oxidation (FO) units treating young, middle-aged, and stabilized landfill leachates. The FO unit was considered as the key process for implementation of the proposed modeling scheme. Four input components such as H(2)O(2)/chemical oxygen demand ratio, H(2)O(2)/Fe(2+) ratio, reaction pH, and reaction time were fuzzified in a Mamdani-type fuzzy inference system to predict the removal efficiencies of chemical oxygen demand, total organic carbon, color, and ammonia nitrogen. A total of 200 rules in the IF-THEN format were established within the framework of a graphical user interface for each fuzzy-logic model. The product (prod) and the center of gravity (centroid) methods were performed as the inference operator and defuzzification methods, respectively, for the proposed prognostic models. Fuzzy-logic predicted results were compared to the outputs of multiple regression models by means of various descriptive statistical indicators, and the proposed methodology was tested against the experimental data. The testing results clearly revealed that the proposed prognostic models showed a superior predictive performance with very high determination coefficients (R (2)) between 0.930 and 0.991. This study indicated a simple means of modeling and potential of a knowledge-based approach for capturing complicated inter-relationships in a highly non-linear problem. Clearly, it was shown that the proposed prognostic models provided a well-suited and cost-effective method to predict removal efficiencies of wastewater parameters prior to discharge to receiving streams.

  16. Complete genome sequencing and evolutionary analysis of Indian isolates of Dengue virus type 2

    Energy Technology Data Exchange (ETDEWEB)

    Dash, Paban Kumar, E-mail: pabandash@rediffmail.com; Sharma, Shashi; Soni, Manisha; Agarwal, Ankita; Parida, Manmohan; Rao, P.V.Lakshmana

    2013-07-05

    Highlights: •Complete genome of Indian DENV-2 was deciphered for the first time in this study. •The recent Indian DENV-2 revealed presence of many unique amino acid residues. •Genotype shift (American to Cosmopolitan) characterizes evolution of DENV-2 in India. •Circulation of a unique clade of DENV-2 in South Asia was identified. -- Abstract: Dengue is the most important arboviral infection of global public health significance. It is now endemic in most parts of the South East Asia including India. Though Dengue virus type 2 (DENV-2) is predominantly associated with major outbreaks in India, complete genome information of Indian DENV-2 is not available. In this study, the full-length genome of five DENV-2 isolates (four from 2001 to 2011 and one from 1960), from different parts of India was determined. The complete genome of the Indian DENV-2 was found to be 10,670 bases long with an open reading frame coding for 3391 amino acids. The recent Indian DENV-2 (2001–2011) revealed a nucleotide sequence identity of around 90% and 97% with an older Indian DENV-2 (1960) and closely related Sri Lankan and Chinese DENV-2 respectively. Presence of unique amino acid residues and non-conservative substitutions in critical amino acid residues of major structural and non-structural proteins was observed in recent Indian DENV-2. Selection pressure analysis revealed positive selection in few amino acid sites of the genes encoding for structural and non-structural proteins. The molecular phylogenetic analysis based on comparison of both complete coding region and envelope protein gene with globally diverse DENV-2 viruses classified the recent Indian isolates into a unique South Asian clade within Cosmopolitan genotype. A shift of genotype from American to Cosmopolitan in 1970s characterized the evolution of DENV-2 in India. Present study is the first report on complete genome characterization of emerging DENV-2 isolates from India and highlights the circulation of a

  17. Complete genome sequencing and evolutionary analysis of Indian isolates of Dengue virus type 2

    International Nuclear Information System (INIS)

    Dash, Paban Kumar; Sharma, Shashi; Soni, Manisha; Agarwal, Ankita; Parida, Manmohan; Rao, P.V.Lakshmana

    2013-01-01

    Highlights: •Complete genome of Indian DENV-2 was deciphered for the first time in this study. •The recent Indian DENV-2 revealed presence of many unique amino acid residues. •Genotype shift (American to Cosmopolitan) characterizes evolution of DENV-2 in India. •Circulation of a unique clade of DENV-2 in South Asia was identified. -- Abstract: Dengue is the most important arboviral infection of global public health significance. It is now endemic in most parts of the South East Asia including India. Though Dengue virus type 2 (DENV-2) is predominantly associated with major outbreaks in India, complete genome information of Indian DENV-2 is not available. In this study, the full-length genome of five DENV-2 isolates (four from 2001 to 2011 and one from 1960), from different parts of India was determined. The complete genome of the Indian DENV-2 was found to be 10,670 bases long with an open reading frame coding for 3391 amino acids. The recent Indian DENV-2 (2001–2011) revealed a nucleotide sequence identity of around 90% and 97% with an older Indian DENV-2 (1960) and closely related Sri Lankan and Chinese DENV-2 respectively. Presence of unique amino acid residues and non-conservative substitutions in critical amino acid residues of major structural and non-structural proteins was observed in recent Indian DENV-2. Selection pressure analysis revealed positive selection in few amino acid sites of the genes encoding for structural and non-structural proteins. The molecular phylogenetic analysis based on comparison of both complete coding region and envelope protein gene with globally diverse DENV-2 viruses classified the recent Indian isolates into a unique South Asian clade within Cosmopolitan genotype. A shift of genotype from American to Cosmopolitan in 1970s characterized the evolution of DENV-2 in India. Present study is the first report on complete genome characterization of emerging DENV-2 isolates from India and highlights the circulation of a

  18. Repeat interruptions in spinocerebellar ataxia type 10 expansions are strongly associated with epileptic seizures

    Science.gov (United States)

    McFarland, Karen N.; Liu, Jilin; Landrian, Ivette; Zeng, Desmond; Raskin, Salmo; Moscovich, Mariana; Gatto, Emilia M.; Ochoa, Adriana; Teive, Hélio A. G.; Rasmussen, Astrid; Ashizawa, Tetsuo

    2014-01-01

    Spinocerebellar ataxia type 10 (SCA10), an autosomal dominant neurodegenerative disorder, is the result of a non-coding, pentanucleotide repeat expansion within intron 9 of the Ataxin 10 gene. SCA10 patients present with pure cerebellar ataxia; yet, some families also have a high incidence of epilepsy. SCA10 expansions containing penta- and heptanucleotide interruption motifs, termed “ATCCT interruptions,” experience large contractions during germline transmission, particularly in paternal lineages. At the same time, these alleles confer an earlier age at onset which contradicts traditional rules of genetic anticipation in repeat expansions. Previously, ATCCT interruptions have been associated with a higher prevalence of epileptic seizures in one Mexican-American SCA10 family. In a large cohort of SCA10 families, we analyzed whether ATCCT interruptions confers a greater risk for developing seizures in these families. Notably, we find that the presence of repeat interruptions within the SCA10 expansion confers a 6.3-fold increase in the risk of an SCA10 patient developing epilepsy (6.2-fold when considering patients of Mexican ancestry only) and a 13.7-fold increase in having a positive family history of epilepsy (10.5-fold when considering patients of Mexican ancestry only). We conclude that the presence of repeat interruptions in SCA10 repeat expansion indicates a significant risk for the epilepsy phenotype and should be considered during genetic counseling. PMID:24318420

  19. An antibody blocking activin type II receptors induces strong skeletal muscle hypertrophy and protects from atrophy.

    Science.gov (United States)

    Lach-Trifilieff, Estelle; Minetti, Giulia C; Sheppard, KellyAnn; Ibebunjo, Chikwendu; Feige, Jerome N; Hartmann, Steffen; Brachat, Sophie; Rivet, Helene; Koelbing, Claudia; Morvan, Frederic; Hatakeyama, Shinji; Glass, David J

    2014-02-01

    The myostatin/activin type II receptor (ActRII) pathway has been identified to be critical in regulating skeletal muscle size. Several other ligands, including GDF11 and the activins, signal through this pathway, suggesting that the ActRII receptors are major regulatory nodes in the regulation of muscle mass. We have developed a novel, human anti-ActRII antibody (bimagrumab, or BYM338) to prevent binding of ligands to the receptors and thus inhibit downstream signaling. BYM338 enhances differentiation of primary human skeletal myoblasts and counteracts the inhibition of differentiation induced by myostatin or activin A. BYM338 prevents myostatin- or activin A-induced atrophy through inhibition of Smad2/3 phosphorylation, thus sparing the myosin heavy chain from degradation. BYM338 dramatically increases skeletal muscle mass in mice, beyond sole inhibition of myostatin, detected by comparing the antibody with a myostatin inhibitor. A mouse version of the antibody induces enhanced muscle hypertrophy in myostatin mutant mice, further confirming a beneficial effect on muscle growth beyond myostatin inhibition alone through blockade of ActRII ligands. BYM338 protects muscles from glucocorticoid-induced atrophy and weakness via prevention of muscle and tetanic force losses. These data highlight the compelling therapeutic potential of BYM338 for the treatment of skeletal muscle atrophy and weakness in multiple settings.

  20. Radio and X-Ray Observations of SN 2006jd: Another Strongly Interacting Type IIn Supernova

    Science.gov (United States)

    Chandra, Poonam; Chevalier, Roger A.; Chugai, Nikolai; Fransson, Claes; Irwin, Christopher M.; Soderberg, Alicia M.; Chakraborti, Sayan; Immler, Stefan

    2012-01-01

    We report four years of radio and X-ray monitoring of the Type IIn supernova SN 2006jd at radio wavelengths with the Very Large Array, Giant Metrewave Radio Telescope and Expanded Very Large Array at X-ray wavelengths with Chandra, XMM-Newton and Swift-XRT. We assume that the radio and X-ray emitting particles are produced by shock interaction with a dense circumstellar medium. The radio emission shows an initial rise that can be attributed to free-free absorption by cool gas mixed into the nonthermal emitting region external free-free absorption is disfavored because of the shape of the rising light curves and the low gas column density inferred along the line of sight to the emission region. The X-ray luminosity implies a preshock circumstellar density approximately 10(exp 6) per cubic meter at a radius r approximately 2 x 10(exp 16) centimeter, but the column density inferred from the photoabsorption of X-rays along the line of sight suggests a significantly lower density. The implication may be an asymmetry in the interaction. The X-ray spectrum shows Fe line emission at 6.9 keV that is stronger than is expected for the conditions in the X-ray emitting gas. We suggest that cool gas mixed into the hot gas plays a role in the line emission. Our radio and X-ray data both suggest the density profile is flatter than r2 because of the slow evolution of the unabsorbed emission.

  1. Strong type 1, but impaired type 2, immune responses contribute to Orientia tsutsugamushi-induced pathology in mice.

    Directory of Open Access Journals (Sweden)

    Lynn Soong

    2014-09-01

    Full Text Available Scrub typhus is a neglected, but important, tropical disease, which puts one-third of the world's population at risk. The disease is caused by Orientia tsutsugamushi, an obligately intracellular Gram-negative bacterium. Dysregulation in immune responses is known to contribute to disease pathogenesis; however, the nature and molecular basis of immune alterations are poorly defined. This study made use of a newly developed murine model of severe scrub typhus and focused on innate regulators and vascular growth factors in O. tsutsugamushi-infected liver, lungs and spleen. We found no activation or even reduction in base-line expression for multiple molecules (IL-7, IL-4, IL-13, GATA3, ROR-γt, and CXCL12 at 2, 6 and 10 days post-infection. This selective impairment in type 2-related immune responses correlated with a significant activation of the genes for IL-1β, IL-6, IL-10, TNF-α, IFN-γ, as well as CXCR3- and CXCR1-related chemokines in inflamed tissues. The elevated angiopoietin (Ang-2 expression and Ang-2/Ang-1 ratios suggested excessive inflammation and the loss of endothelial integrity. These alterations, together with extensive recruitment of myeloperoxidase (MPO-expressing neutrophils and the influx of CD3+ T cells, contributed to acute tissue damage and animal death. This is the first report of selective alterations in a panel of immune regulators during early O. tsutsugamushi infection in intravenously inoculated C57BL/6 mice. Our findings shed new light on the pathogenic mechanisms associated with severe scrub typhus and suggest potential targets for therapeutic investigation.

  2. Identification of a Macrobrachium nipponense C-type lectin with a close evolutionary relationship to vertebrate lectins.

    Science.gov (United States)

    Huang, Xin; Li, Tingting; Jin, Min; Yin, Shaowu; Wang, Wen; Ren, Qian

    2017-07-01

    C-type lectins (CTLs) are involved in the innate immune defense of vertebrates and invertebrates against invading pathogens. This study cloned and characterized a novel C-type lectin (MnCTL) of the oriental river prawn, Macrobrachium nipponense. The cloned MnCTL cDNA encompasses an open reading frame of 774 nucleotides and encodes polypeptides of 257 residues. The deduced MnCTL protein contains a single carbohydrate recognition domain (CRD) with an EPN (Glu-Pro-Asn) motif in calcium-binding site 2. Phylogenetic analysis indicated that MnCTL has a closer evolutionary relationship with vertebrate lectins than with invertebrate lectins. Tissue expression analysis showed that high levels of MnCTL are ubiquitously distributed in the gills and stomach of M. nipponense. Quantitative real-time RT-PCR (qRT-PCR) analysis showed that MnCTL expression was up-regulated by bacteria or white spot syndrome virus (WSSV) challenge. Knock-down of the MnCTL gene in WSSV-challenged prawns significantly decreased MnALF1 and MnALF2 transcript levels. The recombinant MnCRD (rMnCRD) agglutinated both Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Vibrio parahaemolyticus) in the presence of calcium. Furthermore, rMnCRD could bind to all the tested bacteria with different activities. The sugar-binding assay showed that rMnCRD was able to bind lipopolysaccharide and peptidoglycan in a concentration-dependent manner. In addition, rMnCRD could accelerate bacterial clearance. On the contrary, MnCTL silencing by dsRNA interference could weaken the bacterial clearance ability. All these findings implicated MnCTL were involved in the antiviral and antibacterial innate immunity of M. nipponense. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. A new chemo-evolutionary population synthesis model for early-type galaxies; 2, Observations and Results

    NARCIS (Netherlands)

    Vazdekis, A.; Peletier, R. F.; Beckman, J. E.; Casuso, E.

    1997-01-01

    Submitted to: Astrophys. J. Suppl. Ser. Abstract: We present here the results of applying a new chemo-evolutionary stellar population model developed by ourselves in a previous paper (Vazdekis et al. 1996) to new high quality observational data of the nuclear regions of two representative elliptical

  4. A new chemo-evolutionary population synthesis model for early-type galaxies .2. Observations and results

    NARCIS (Netherlands)

    Vazdekis, A; Peletier, RF; Beckman, JE; Casuso, E

    We present the results of applying a new chemo-evolutionary stellar population model, developed in a previous paper, to new high-quality observational data of the nuclear regions of two representative elliptical galaxies and the bulge of the Sombrero galaxy. Here we fit in detail similar to 20

  5. Evolutionary Nephrology.

    Science.gov (United States)

    Chevalier, Robert L

    2017-05-01

    Progressive kidney disease follows nephron loss, hyperfiltration, and incomplete repair, a process described as "maladaptive." In the past 20 years, a new discipline has emerged that expands research horizons: evolutionary medicine. In contrast to physiologic (homeostatic) adaptation, evolutionary adaptation is the result of reproductive success that reflects natural selection. Evolutionary explanations for physiologically maladaptive responses can emerge from mismatch of the phenotype with environment or evolutionary tradeoffs. Evolutionary adaptation to a terrestrial environment resulted in a vulnerable energy-consuming renal tubule and a hypoxic, hyperosmolar microenvironment. Natural selection favors successful energy investment strategy: energy is allocated to maintenance of nephron integrity through reproductive years, but this declines with increasing senescence after ~40 years of age. Risk factors for chronic kidney disease include restricted fetal growth or preterm birth (life history tradeoff resulting in fewer nephrons), evolutionary selection for APOL1 mutations (that provide resistance to trypanosome infection, a tradeoff), and modern life experience (Western diet mismatch leading to diabetes and hypertension). Current advances in genomics, epigenetics, and developmental biology have revealed proximate causes of kidney disease, but attempts to slow kidney disease remain elusive. Evolutionary medicine provides a complementary approach by addressing ultimate causes of kidney disease. Marked variation in nephron number at birth, nephron heterogeneity, and changing susceptibility to kidney injury throughout life history are the result of evolutionary processes. Combined application of molecular genetics, evolutionary developmental biology (evo-devo), developmental programming and life history theory may yield new strategies for prevention and treatment of chronic kidney disease.

  6. On the source of the dust extinction in type Ia supernovae and the discovery of anomalously strong Na I absorption

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, M. M.; Morrell, Nidia; Hsiao, E. Y.; Campillay, Abdo; Contreras, Carlos [Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena (Chile); Simon, Joshua D.; Burns, Christopher R.; Persson, Sven E.; Thompson, I. B.; Freedman, Wendy L. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101 (United States); Cox, Nick L. J. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D bus 2401, 3001 Leuven (Belgium); Foley, Ryan J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Karakas, Amanda I. [Research School of Astronomy and Astrophysics, The Australian National University, Weston, ACT 2611 (Australia); Patat, F. [European Southern Observatory (ESO), Karl Schwarschild Strasse 2, D-85748, Garching bei München (Germany); Sternberg, A. [Max Planck Institute for Astrophysics, Karl Schwarzschild Strasse 1, D-85741 Garching bei München (Germany); Williams, R. E. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Gal-Yam, A. [Benoziyo Center for Astrophysics, Faculty of Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Leonard, D. C. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Folatelli, Gastón, E-mail: mmp@lco.cl [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, the University of Tokyo, Kashiwa 277-8583 (Japan); and others

    2013-12-10

    High-dispersion observations of the Na I D λλ5890, 5896 and K I λλ7665, 7699 interstellar lines, and the diffuse interstellar band at 5780 Å in the spectra of 32 Type Ia supernovae are used as an independent means of probing dust extinction. We show that the dust extinction of the objects where the diffuse interstellar band at 5780 Å is detected is consistent with the visual extinction derived from the supernova colors. This strongly suggests that the dust producing the extinction is predominantly located in the interstellar medium of the host galaxies and not in circumstellar material associated with the progenitor system. One quarter of the supernovae display anomalously large Na I column densities in comparison to the amount of dust extinction derived from their colors. Remarkably, all of the cases of unusually strong Na I D absorption correspond to 'Blueshifted' profiles in the classification scheme of Sternberg et al. This coincidence suggests that outflowing circumstellar gas is responsible for at least some of the cases of anomalously large Na I column densities. Two supernovae with unusually strong Na I D absorption showed essentially normal K I column densities for the dust extinction implied by their colors, but this does not appear to be a universal characteristic. Overall, we find the most accurate predictor of individual supernova extinction to be the equivalent width of the diffuse interstellar band at 5780 Å, and provide an empirical relation for its use. Finally, we identify ways of producing significant enhancements of the Na abundance of circumstellar material in both the single-degenerate and double-degenerate scenarios for the progenitor system.

  7. Evolutionary Demography

    DEFF Research Database (Denmark)

    Levitis, Daniel

    2015-01-01

    of biological and cultural evolution. Demographic variation within and among human populations is influenced by our biology, and therefore by natural selection and our evolutionary background. Demographic methods are necessary for studying populations of other species, and for quantifying evolutionary fitness...

  8. Type 2 diabetes associated variants of KCNQ1 strongly confer the risk of cardiovascular disease among the Saudi Arabian population

    Directory of Open Access Journals (Sweden)

    Maha S. Al-Shammari

    2017-08-01

    Full Text Available Abstract Genome-wide association studies have identified several loci associated with an increased risk for cardiovascular disease (CVD and type 2 diabetes (T2D. Polymorphisms within the KCNQ1 (potassium voltage-gated channel, KQT-like subfamily, member 1 gene are consistently associated with T2D in a number of populations. The current study was undertaken to evaluate the association of 3 polymorphisms of KCNQ1 (rs2237892, rs151290 and rs2237895 with T2D and/or CVD. Patients diagnosed with either T2D (320 patients, CVD (250 patients or both (60 patients and 516 healthy controls were genotyped by TaqMan assay run on a real time PCR thermocycler. A statistically significant association was found for SNPs rs151290 (OR = 1.76; 95%CI = 1.02-3.05; p = 0.0435 and rs2237895 (OR = 2.49; 95%CI = 1.72-3.61; p < 0.0001 with CVD. SNP rs151290 (OR = 7.43; 95%CI = 1.00-55.22; p = 0.0499 showed a strong association in patients with both T2D and CVD. None of the SNPs showed any significant association with T2D. Haploview analysis showed that the ACC (rs151290, rs2237892 and rs2237895 haplotype is the most significant risk allele combination for CVD, while CCA is the most significant risk haplotype for co-morbidity with T2D. KCNQ1 polymorphism at SNPs rs151290 and rs2237895 is strongly associated with CVD in this population, but presented no association with T2D.

  9. Evaluation of DNA typing as a positive identification method for soft and hard tissues immersed in strong acids.

    Science.gov (United States)

    Robino, C; Pazzi, M; Di Vella, G; Martinelli, D; Mazzola, L; Ricci, U; Testi, R; Vincenti, M

    2015-11-01

    Identification of human remains can be hindered by several factors (e.g., traumatic mutilation, carbonization or decomposition). Moreover, in some criminal cases, offenders may purposely adopt various expedients to thwart the victim's identification, including the dissolution of body tissues by the use of corrosive reagents, as repeatedly reported in the past for Mafia-related murders. By means of an animal model, namely porcine samples, we evaluated standard DNA typing as a method for identifying soft (muscle) and hard (bone and teeth) tissues immersed in strong acids (hydrochloric, nitric and sulfuric acid) or in mixtures of acids (aqua regia). Samples were tested at different time intervals, ranging between 2 and 6h (soft tissues) and 2-28 days (hard tissues). It was shown that, in every type of acid, complete degradation of the DNA extracted from soft tissues preceded tissue dissolution and could be observed within 4h of immersion. Conversely, high molecular weight DNA amenable to STR analysis could be isolated from hard tissues as long as cortical bone fragments were still present (28 days for sulfuric acid, 7 days for nitric acid, 2 days for hydrochloric acid and aqua regia), or the integrity of the dental pulp chamber was preserved (7 days, in sulfuric acid only). The results indicate that DNA profiling of acid-treated body parts (in particular, cortical bone) is still feasible at advanced stages of corrosion, even when the morphological methods used in forensic anthropology and odontology can no longer be applied for identification purposes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. SULF2 Strongly Prediposes to Fasting and Postprandial Triglycerides in Patients with Obesity and Type 2 Diabetes Mellitus

    Science.gov (United States)

    Hassing, H. Carlijne; Surendran, R. Preethi; Derudas, Bruno; Verrijken, An; Francque, Sven M.; Mooij, Hans L.; Bernelot Moens, Sophie J.; ’t Hart, Leen M.; Nijpels, Giel; Dekker, Jacqueline M.; Williams, Kevin Jon; Stroes, Erik S. G.; Van Gaal, Luc F.; Staels, Bart; Nieuwdorp, Max; Dallinga-Thie, Geesje M.

    2014-01-01

    Objective Hepatic overexpression of sulfatase-2 (SULF2), a heparan sulfate remodelling enzyme, strongly contributes to high triglyceride (TG) levels in obese, type 2 diabetic (T2DM) db/db mice. Nevertheless, data in humans are lacking. Here we sought to investigate the association of human hepatic SULF2 expression and SULF2 gene variants with TG metabolism in patients with obesity and/or T2DM. Design and Methods Liver biopsies from 121 obese subjects were analyzed for relations between hepatic SULF2 mRNA levels and plasma TG. Associations between seven SULF2 tagSNPs and TG levels were assessed in 210 obese T2DM subjects with dyslipidemia. Replication of positive findings was performed in 1316 independent obese T2DM patients. Postprandial TRL clearance was evaluated in 29 obese T2DM subjects stratified by SULF2 genotype. Results Liver SULF2 expression was significantly associated with fasting plasma TG (r = 0.271; p=0.003) in obese subjects. The SULF2 rs2281279(A>G) SNP was reproducibly associated with lower fasting plasma TG levels in obese T2DM subjects (p<0.05). Carriership of the minor G allele was associated with lower levels of postprandial plasma TG (P<0.05) and retinyl esters (RE) levels (P<0.001). Conclusions These findings implicate SULF2 as potential therapeutic target in the atherogenic dyslipidemia of obesity and T2DM. PMID:24339435

  11. Evolutionary Demography

    DEFF Research Database (Denmark)

    Levitis, Daniel

    2015-01-01

    Demography is the quantitative study of population processes, while evolution is a population process that influences all aspects of biological organisms, including their demography. Demographic traits common to all human populations are the products of biological evolution or the interaction...... of biological and cultural evolution. Demographic variation within and among human populations is influenced by our biology, and therefore by natural selection and our evolutionary background. Demographic methods are necessary for studying populations of other species, and for quantifying evolutionary fitness...

  12. Glucose Variations and Activity Are Strongly Coupled in Sleep and Wake in Young Adults With Type 1 Diabetes.

    Science.gov (United States)

    Farabi, Sarah S; Carley, David W; Quinn, Lauretta

    2017-05-01

    Glucose variations are common throughout sleep and wakefulness in people with type 1 diabetes mellitus (T1DM). The objective of this investigation was to characterize the time-varying coupling between glucose and unstructured physical activity over a 60-hr period in young adults with T1DM. The hypothesis was that coupling would differ during sleep versus wakefulness and would exhibit circadian variations. Young adults with T1DM treated with an insulin pump participated in the study. Glucose variations were monitored with a continuous glucose monitoring system, and activity was assessed using an activity-monitoring band worn on the nondominant wrist. Simultaneous glucose and physical activity data across a continuous 60-hr period were used for analysis. Wavelet coherence analysis was employed to quantify the coupling between physical activity and glucose. Cosinor analysis was used to assess whether glucose/activity coherence exhibited significant circadian variations. Participants comprised 23 adults, aged 18-30 years, with T1DM. Coherence analysis demonstrated substantial coupling between physical activity and glucose variations during both wakefulness and sleep. For rapid (10-30 min) fluctuations, mean coherence was higher during sleep than wakefulness ( F = 10.86, p = .003). Rapid glucose variations consistently led to changes in activity ( p = .001) during sleep but not during wake. Cosinor analysis revealed significant circadian modulation of glucose/activity coupling, especially for fluctuation periods 2-4 hr. Unstructured physical activity and glucose variations demonstrated strong time- and frequency-dependent coupling over a 60-hr period in young adults with T1DM, with sleep/wake differences and circadian modulation evident in this relationship.

  13. Evolutionary Awareness

    Directory of Open Access Journals (Sweden)

    Gregory Gorelik

    2014-10-01

    Full Text Available In this article, we advance the concept of “evolutionary awareness,” a metacognitive framework that examines human thought and emotion from a naturalistic, evolutionary perspective. We begin by discussing the evolution and current functioning of the moral foundations on which our framework rests. Next, we discuss the possible applications of such an evolutionarily-informed ethical framework to several domains of human behavior, namely: sexual maturation, mate attraction, intrasexual competition, culture, and the separation between various academic disciplines. Finally, we discuss ways in which an evolutionary awareness can inform our cross-generational activities—which we refer to as “intergenerational extended phenotypes”—by helping us to construct a better future for ourselves, for other sentient beings, and for our environment.

  14. Evolutionary Expectations

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    , they are correlated among people who share environments because these individuals satisfice within their cognitive bounds by using cues in order of validity, as opposed to using cues arbitrarily. Any difference in expectations thereby arise from differences in cognitive ability, because two individuals with identical......The concept of evolutionary expectations descends from cue learning psychology, synthesizing ideas on rational expectations with ideas on bounded rationality, to provide support for these ideas simultaneously. Evolutionary expectations are rational, but within cognitive bounds. Moreover...... cognitive bounds will perceive business opportunities identically. In addition, because cues provide information about latent causal structures of the environment, changes in causality must be accompanied by changes in cognitive representations if adaptation is to be maintained. The concept of evolutionary...

  15. Applying Evolutionary Anthropology

    Science.gov (United States)

    Gibson, Mhairi A; Lawson, David W

    2015-01-01

    Evolutionary anthropology provides a powerful theoretical framework for understanding how both current environments and legacies of past selection shape human behavioral diversity. This integrative and pluralistic field, combining ethnographic, demographic, and sociological methods, has provided new insights into the ultimate forces and proximate pathways that guide human adaptation and variation. Here, we present the argument that evolutionary anthropological studies of human behavior also hold great, largely untapped, potential to guide the design, implementation, and evaluation of social and public health policy. Focusing on the key anthropological themes of reproduction, production, and distribution we highlight classic and recent research demonstrating the value of an evolutionary perspective to improving human well-being. The challenge now comes in transforming relevance into action and, for that, evolutionary behavioral anthropologists will need to forge deeper connections with other applied social scientists and policy-makers. We are hopeful that these developments are underway and that, with the current tide of enthusiasm for evidence-based approaches to policy, evolutionary anthropology is well positioned to make a strong contribution. PMID:25684561

  16. Evolutionary robotics

    Indian Academy of Sciences (India)

    In evolutionary robotics, a suitable robot control system is developed automatically through evolution due to the interactions between the robot and its environment. It is a complicated task, as the robot and the environment constitute a highly dynamical system. Several methods have been tried by various investigators to ...

  17. Core principles of evolutionary medicine

    Science.gov (United States)

    Grunspan, Daniel Z; Nesse, Randolph M; Barnes, M Elizabeth; Brownell, Sara E

    2018-01-01

    Abstract Background and objectives Evolutionary medicine is a rapidly growing field that uses the principles of evolutionary biology to better understand, prevent and treat disease, and that uses studies of disease to advance basic knowledge in evolutionary biology. Over-arching principles of evolutionary medicine have been described in publications, but our study is the first to systematically elicit core principles from a diverse panel of experts in evolutionary medicine. These principles should be useful to advance recent recommendations made by The Association of American Medical Colleges and the Howard Hughes Medical Institute to make evolutionary thinking a core competency for pre-medical education. Methodology The Delphi method was used to elicit and validate a list of core principles for evolutionary medicine. The study included four surveys administered in sequence to 56 expert panelists. The initial open-ended survey created a list of possible core principles; the three subsequent surveys winnowed the list and assessed the accuracy and importance of each principle. Results Fourteen core principles elicited at least 80% of the panelists to agree or strongly agree that they were important core principles for evolutionary medicine. These principles over-lapped with concepts discussed in other articles discussing key concepts in evolutionary medicine. Conclusions and implications This set of core principles will be helpful for researchers and instructors in evolutionary medicine. We recommend that evolutionary medicine instructors use the list of core principles to construct learning goals. Evolutionary medicine is a young field, so this list of core principles will likely change as the field develops further. PMID:29493660

  18. Exercise and cognitive function: a hypothesis for the association of type II diabetes mellitus and Alzheimer's disease from an evolutionary perspective

    Directory of Open Access Journals (Sweden)

    Brito Gilberto NO

    2009-09-01

    Full Text Available Abstract The association of type II diabetes mellitus (DM2 with Alzheimer's disease (AD has received considerable attention in recent years. In the present paper, a hypothesis for this association from an evolutionary perspective, with emphasis on the close interplay between exercise and cognitive function, will be advanced in order to provide a biological rationale for the notion that the fundamental metabolic features of DM2 act in the brain over a protracted time span to induce the neuropathological characteristics of Alzheimer's disease thereby producing cognitive impairment. It is hoped that this hypothesis puts the association of DM2 and AD on firm conceptual grounds from a biological perspective and offers directions for further research.

  19. Is Vocabulary a Strong Variable Predicting Reading Comprehension and Does the Prediction Degree of Vocabulary Vary According to Text Types

    Science.gov (United States)

    Yildirim, Kasim; Yildiz, Mustafa; Ates, Seyit

    2011-01-01

    The purpose of this study was to explore whether there was a significant correlation between vocabulary and reading comprehension in terms of text types as well as whether the vocabulary was a predictor of reading comprehension in terms of text types. In this regard, the correlational research design was used to explain specific research…

  20. Evolutionary Finance

    OpenAIRE

    Igor V. Evstigneev; Thorsten Hens; Klaus Reiner Schenk-Hoppé

    2008-01-01

    Evolutionary finance studies the dynamic interaction of investment strategies in financial markets. This market interaction generates a stochastic wealth dynamics on a heterogenous population of traders through the fluctuation of asset prices and their random payoffs. Asset prices are endogenously determined through short-term market clearing. Investors' portfolio choices are characterized by investment strategies which provide a descriptive model of decision behavior. The mathematical framew...

  1. Evolutionary institutionalism.

    Science.gov (United States)

    Fürstenberg, Dr Kai

    Institutions are hard to define and hard to study. Long prominent in political science have been two theories: Rational Choice Institutionalism (RCI) and Historical Institutionalism (HI). Arising from the life sciences is now a third: Evolutionary Institutionalism (EI). Comparative strengths and weaknesses of these three theories warrant review, and the value-to-be-added by expanding the third beyond Darwinian evolutionary theory deserves consideration. Should evolutionary institutionalism expand to accommodate new understanding in ecology, such as might apply to the emergence of stability, and in genetics, such as might apply to political behavior? Core arguments are reviewed for each theory with more detailed exposition of the third, EI. Particular attention is paid to EI's gene-institution analogy; to variation, selection, and retention of institutional traits; to endogeneity and exogeneity; to agency and structure; and to ecosystem effects, institutional stability, and empirical limitations in behavioral genetics. RCI, HI, and EI are distinct but complementary. Institutional change, while amenable to rational-choice analysis and, retrospectively, to criticaljuncture and path-dependency analysis, is also, and importantly, ecological. Stability, like change, is an emergent property of institutions, which tend to stabilize after change in a manner analogous to allopatric speciation. EI is more than metaphorically biological in that institutional behaviors are driven by human behaviors whose evolution long preceded the appearance of institutions themselves.

  2. Internalin profiling and multilocus sequence typing suggest four Listeria innocua subgroups with different evolutionary distances from Listeria monocytogenes

    OpenAIRE

    Chen, Jianshun; Chen, Qiaomiao; Jiang, Lingli; Cheng, Changyong; Bai, Fan; Wang, Jun; Mo, Fan; Fang, Weihuan

    2010-01-01

    Abstract Background Ecological, biochemical and genetic resemblance as well as clear differences of virulence between L. monocytogenes and L. innocua make this bacterial clade attractive as a model to examine evolution of pathogenicity. This study was attempted to examine the population structure of L. innocua and the microevolution in the L. innocua-L. monocytogenes clade via profiling of 37 internalin genes and multilocus sequence typing based on the sequences of 9 unlinked genes gyrB, sigB...

  3. Evolutionary Dynamics of Pathoadaptation Revealed by Three Independent Acquisitions of the VirB/D4 Type IV Secretion System in Bartonella.

    Science.gov (United States)

    Harms, Alexander; Segers, Francisca H I D; Quebatte, Maxime; Mistl, Claudia; Manfredi, Pablo; Körner, Jonas; Chomel, Bruno B; Kosoy, Michael; Maruyama, Soichi; Engel, Philipp; Dehio, Christoph

    2017-03-01

    The α-proteobacterial genus Bartonella comprises a group of ubiquitous mammalian pathogens that are studied as a model for the evolution of bacterial pathogenesis. Vast abundance of two particular phylogenetic lineages of Bartonella had been linked to enhanced host adaptability enabled by lineage-specific acquisition of a VirB/D4 type IV secretion system (T4SS) and parallel evolution of complex effector repertoires. However, the limited availability of genome sequences from one of those lineages as well as other, remote branches of Bartonella has so far hampered comprehensive understanding of how the VirB/D4 T4SS and its effectors called Beps have shaped Bartonella evolution. Here, we report the discovery of a third repertoire of Beps associated with the VirB/D4 T4SS of B. ancashensis, a novel human pathogen that lacks any signs of host adaptability and is only distantly related to the two species-rich lineages encoding a VirB/D4 T4SS. Furthermore, sequencing of ten new Bartonella isolates from under-sampled lineages enabled combined in silico analyses and wet lab experiments that suggest several parallel layers of functional diversification during evolution of the three Bep repertoires from a single ancestral effector. Our analyses show that the Beps of B. ancashensis share many features with the two other repertoires, but may represent a more ancestral state that has not yet unleashed the adaptive potential of such an effector set. We anticipate that the effectors of B. ancashensis will enable future studies to dissect the evolutionary history of Bartonella effectors and help unraveling the evolutionary forces underlying bacterial host adaptation. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  4. Multi types DG expansion dynamic planning in distribution system under stochastic conditions using Covariance Matrix Adaptation Evolutionary Strategy and Monte-Carlo simulation

    International Nuclear Information System (INIS)

    Sadeghi, Mahmood; Kalantar, Mohsen

    2014-01-01

    Highlights: • Defining a DG dynamic planning problem. • Applying a new evolutionary algorithm called “CMAES” in planning process. • Considering electricity price and fuel price variation stochastic conditions. • Scenario generation and reduction with MCS and backward reduction programs. • Considering approximately all of the costs of the distribution system. - Abstract: This paper presents a dynamic DG planning problem considering uncertainties related to the intermittent nature of the DG technologies such as wind turbines and solar units in addition to the stochastic economic conditions. The stochastic economic situation includes the uncertainties related to the fuel and electricity price of each year. The Monte Carlo simulation is used to generate the possible scenarios of uncertain situations and the produced scenarios are reduced through backward reduction program. The aim of this paper is to maximize the revenue of the distribution system through the benefit cost analysis alongside the encouraging and punishment functions. In order to close to reality, the different growth rates for the planning period are selected. In this paper the Covariance Matrix Adaptation Evolutionary Strategy is introduced and is used to find the best planning scheme of the DG units. The different DG types are considered in the planning problem. The main assumption of this paper is that the DISCO is the owner of the distribution system and the DG units. The proposed method is tested on a 9 bus test distribution system and the results are compared with the known genetic algorithm and PSO methods to show the applicability of the CMAES method in this problem

  5. The number of metastatic sites for stage IIIA endometrial carcinoma, endometrioid cell type, is a strong negative prognostic factor

    NARCIS (Netherlands)

    Jobsen, Jan J.; Naudin ten Cate, Lambert; Lybeert, Marnix L.M.; van der Steen-Banasik, Elzbieta M.; Scholten, A.M.; van der Palen, Jacobus Adrianus Maria; van der Palen, J.; Slot, Annerie; Stenfert Kroese, Marika C.; Schutter, Eltjo M.; Siesling, Sabine

    2010-01-01

    The aim of this study was to look at the impact of the number of sites with tumour involvement on outcome for patients with stage IIIA endometrioid-type endometrial carcinoma. Patients and methods: 141 patients stage IIIA were included. A central histopathological review was performed. Patients

  6. Comparative study of two typing methods, hsp65 PRA and ITS sequencing, revealed a possible evolutionary link between Mycobacterium kansasii type I and II isolates.

    Science.gov (United States)

    Iwamoto, Tomotada; Saito, Hajime

    2006-01-01

    One hundred and ninety-eight clinical isolates of Mycobacterium kansasii collected between 2003 and 2004 in Japan were genotyped by PCR and restriction enzyme analysis (PRA) and 16S-23S internal transcribed spacer (ITS) sequencing. The results demonstrated that clinical isolates of M. kansasii in Japan are almost exclusively of the type I PRA genotype, as is the case in other countries. Although the results of subtyping using the 16S-23S ITS sequence were generally consistent with subtyping using hsp65 PRA, four strains showed a discrepancy between the two methods. Sequence analysis of the hsp65, gyrB and 16S rRNA genes and the ITS sequence of the four strains suggests that they branched from type II and could be considered an ancestral strain of the type I strain. The newly recognized strains were designated as intermediate type I.

  7. Multilocus Sequence Typing Reveals Relevant Genetic Variation and Different Evolutionary Dynamics among Strains of Xanthomonas arboricola pv. juglandis

    Directory of Open Access Journals (Sweden)

    Marco Scortichini

    2010-11-01

    Full Text Available Forty-five Xanthomonas arboricola pv. juglandis (Xaj strains originating from Juglans regia cultivation in different countries were molecularly typed by means of MultiLocus Sequence Typing (MLST, using acnB, gapA, gyrB and rpoD gene fragments. A total of 2.5 kilobases was used to infer the phylogenetic relationship among the strains and possible recombination events. Haplotype diversity, linkage disequilibrium analysis, selection tests, gene flow estimates and codon adaptation index were also assessed. The dendrograms built by maximum likelihood with concatenated nucleotide and amino acid sequences revealed two major and two minor phylotypes. The same haplotype was found in strains originating from different continents, and different haplotypes were found in strains isolated in the same year from the same location. A recombination breakpoint was detected within the rpoD gene fragment. At the pathovar level, the Xaj populations studied here are clonal and under neutral selection. However, four Xaj strains isolated from walnut fruits with apical necrosis are under diversifying selection, suggesting a possible new adaptation. Gene flow estimates do not support the hypothesis of geographic isolation of the strains, even though the genetic diversity between the strains increases as the geographic distance between them increases. A triplet deletion, causing the absence of valine, was found in the rpoD fragment of all 45 Xaj strains when compared with X. axonopodis pv. citri strain 306. The codon adaptation index was high in all four genes studied, indicating a relevant metabolic activity.

  8. Pulse pressure strongly predicts cardiovascular disease risk in patients with type 2 diabetes from the Swedish National Diabetes Register (NDR).

    Science.gov (United States)

    Nilsson, P M; Cederholm, J; Eeg-Olofsson, K; Eliasson, B; Zethelius, B; Gudbjörnsdóttir, S

    2009-12-01

    To analyze pulse pressure (PP) as a risk predictor for coronary heart disease (CHD), stroke and cardiovascular disease (CVD; CHD and/or stroke) in type 2 diabetic patients. A total of 11,128 female and male type 2 diabetic patients with known baseline PP values and no CVD, aged 50-74 years, were followed for a mean duration of 5.6 years (1998-2003). A subgroup of 5521 patients with known mean PP values (mean values at baseline and at the end of the study) was also included. Hazard ratios (HRs) with 95% CI for fatal/nonfatal CHD with baseline or mean PP>or=75mmHg, compared to diabetes duration, HbA(1c), body mass index (BMI), lipid-reducing drugs, microalbuminuria > 20microg/min, antihypertensive drugs and hypoglycaemic treatment, using Cox regression analyses. Fully-adjusted respective HRs for stroke were 1.17 (0.98-1.39) and 1.21 (0.90-1.61) and, for CVD, 1.23 (1.10-1.37; Por=75mmHg were to be avoided, then 15% and 17% of CHD and or CVD, cases, respectively, in such a cohort might be prevented after multivariable adjustments, with a further 10% of cases avoided if also adjusted for MBP and age. Increasing baseline MBP, age and microalbuminuria were independently and significantly associated (Prisk predictor of CVD in type 2 diabetic patients, and lowering PP can lead to a marked reduction in risk.

  9. The Dirichlet problem for a mixed-type equation with strong characteristic degeneracy and a singular coefficient

    Directory of Open Access Journals (Sweden)

    Rimma M. Safina

    2017-04-01

    Full Text Available In this paper we consider the first boundary value problem in a rectangular area for a mixed-type equation of the second kind with a singular coefficient. The criterion of the uniqueness of the problem solution is determined. The uniqueness of the problem solution is proved on the basis of completeness of the system of eigenfunctions of the corresponding one-dimensional spectral problem. The solution of the problem is built explicitly as a sum of Fourier–Bessel. There is the problem of the small denominators that appears when justifying the uniform convergence of the constructed series. In this regard, an evaluation of separateness from zero with a corresponding small denominator asymptotic behavior is found. This estimate has allowed to prove the convergence of the series and its derivatives up to the second order, and the existence theorem for the class of regular solutions of this equation.

  10. Thrombospondin Type-1 Repeat Domain-Containing Proteins Are Strongly Expressed in the Head Region of Hydra.

    Science.gov (United States)

    Hamaguchi-Hamada, Kayoko; Kurumata-Shigeto, Mami; Minobe, Sumiko; Fukuoka, Nozomi; Sato, Manami; Matsufuji, Miyuki; Koizumi, Osamu; Hamada, Shun

    2016-01-01

    The head region of Hydra, the hypostome, is a key body part for developmental control and the nervous system. We herein examined genes specifically expressed in the head region of Hydra oligactis using suppression subtractive hybridization (SSH) cloning. A total of 1414 subtracted clones were sequenced and found to be derived from at least 540 different genes by BLASTN analyses. Approximately 25% of the subtracted clones had sequences encoding thrombospondin type-1 repeat (TSR) domains, and were derived from 17 genes. We identified 11 TSR domain-containing genes among the top 36 genes that were the most frequently detected in our SSH library. Whole-mount in situ hybridization analyses confirmed that at least 13 out of 17 TSR domain-containing genes were expressed in the hypostome of Hydra oligactis. The prominent expression of TSR domain-containing genes suggests that these genes play significant roles in the hypostome of Hydra oligactis.

  11. Thrombospondin Type-1 Repeat Domain-Containing Proteins Are Strongly Expressed in the Head Region of Hydra.

    Directory of Open Access Journals (Sweden)

    Kayoko Hamaguchi-Hamada

    Full Text Available The head region of Hydra, the hypostome, is a key body part for developmental control and the nervous system. We herein examined genes specifically expressed in the head region of Hydra oligactis using suppression subtractive hybridization (SSH cloning. A total of 1414 subtracted clones were sequenced and found to be derived from at least 540 different genes by BLASTN analyses. Approximately 25% of the subtracted clones had sequences encoding thrombospondin type-1 repeat (TSR domains, and were derived from 17 genes. We identified 11 TSR domain-containing genes among the top 36 genes that were the most frequently detected in our SSH library. Whole-mount in situ hybridization analyses confirmed that at least 13 out of 17 TSR domain-containing genes were expressed in the hypostome of Hydra oligactis. The prominent expression of TSR domain-containing genes suggests that these genes play significant roles in the hypostome of Hydra oligactis.

  12. Evidence for an early evolutionary emergence of γ-type carbonic anhydrases as components of mitochondrial respiratory complex I

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    Gray Michael W

    2010-06-01

    Full Text Available Abstract Background The complexity of mitochondrial complex I (CI; NADH:ubiquinone oxidoreductase has increased considerably relative to the homologous complex in bacteria. Comparative analyses of CI composition in animals, fungi and land plants/green algae suggest that novel components of mitochondrial CI include a set of 18 proteins common to all eukaryotes and a variable number of lineage-specific subunits. In plants and green algae, several purportedly plant-specific proteins homologous to γ-type carbonic anhydrases (γCA have been identified as components of CI. However, relatively little is known about CI composition in the unicellular protists, the characterizations of which are essential to our understanding of CI evolution. Results We have performed a tandem mass spectrometric characterization of CI from the amoeboid protozoon Acanthamoeba castellanii. Among the proteins identified were two γCA homologs, AcCa1 and AcCa2, demonstrating that γCA proteins are not specific to plants/green algae. In fact, through bioinformatics searches we detected γCA homologs in diverse protist lineages, and several of these homologs are predicted to possess N-terminal mitochondrial targeting peptides. Conclusions The detection of γCAs in CI of Acanthamoeba, considered to be a closer relative of animals and fungi than plants, suggests that γCA proteins may have been an ancestral feature of mitochondrial CI, rather than a novel, plant-specific addition. This assertion is supported by the presence of genes encoding γCAs in the nuclear genomes of a wide variety of eukaryotes. Together, these findings emphasize the importance of a phylogenetically broad characterization of CI for elucidating CI evolution in eukaryotes.

  13. Evolutionary Models of Red Supergiants: Evidence for A Metallicity-dependent Mixing Length and Implications for Type IIP Supernova Progenitors

    Science.gov (United States)

    Chun, Sang-Hyun; Yoon, Sung-Chul; Jung, Moo-Keon; Kim, Dong Uk; Kim, Jihoon

    2018-01-01

    Recent studies on the temperatures of red supergiants (RSGs) in the local universe provide us with an excellent observational constraint on RSG models. We calibrate the mixing length parameter by comparing model predictions with the empirical RSG temperatures in Small and Large Magellanic Clouds, Milky Way, and M31, which are inferred from the TiO band and the spectral energy distribution (SED). Although our RSG models are computed with the MESA code, our result may be applied to other stellar evolution codes, including the BEC and TWIN codes. We find evidence that the mixing length increases with increasing metallicity for both cases where the TiO and SED temperatures of RSGs are used for the calibration. Together with the recent finding of a similar correlation in low-mass red giants by Tayar et al., this implies that the metallicity dependence of the mixing length is a universal feature in post-main sequence stars of both low and high masses. Our result implies that typical Type IIP supernova (SN IIP) progenitors with initial masses of ∼ 10{--}16 {M}ȯ have a radius range of 400 {R}ȯ ≲ R≲ 800 {R}ȯ regardless of metallicity. As an auxiliary result of this study, we find that the hydrogen-rich envelope mass of SN IIP progenitors for a given initial mass is predicted to be largely independent of metallicity if the Ledoux criterion with slow semiconvection is adopted, while the Schwarzschild models predict systematically more massive hydrogen-rich envelopes for lower metallicity.

  14. Evolutionary trends of European bat lyssavirus type 2 including genetic characterization of Finnish strains of human and bat origin 24 years apart.

    Science.gov (United States)

    Jakava-Viljanen, Miia; Miia, Jakava-Viljanen; Nokireki, Tiina; Tiina, Nokireki; Sironen, Tarja; Tarja, Sironen; Vapalahti, Olli; Olli, Vapalahti; Sihvonen, Liisa; Liisa, Sihvonen; Huovilainen, Anita; Anita, Huovilainen

    2015-06-01

    Among other Lyssaviruses, Daubenton's and pond-bat-related European bat lyssavirus type 2 (EBLV-2) can cause human rabies. To investigate the diversity and evolutionary trends of EBLV-2, complete genome sequences of two Finnish isolates were analysed. One originated from a human case in 1985, and the other originated from a bat in 2009. The overall nucleotide and deduced amino acid sequence identity of the two Finnish isolates were high, as well as the similarity to fully sequenced EBLV-2 strains originating from the UK and the Netherlands. In phylogenetic analysis, the EBLV-2 strains formed a monophyletic group that was separate from other bat-type lyssaviruses, with significant support. EBLV-2 shared the most recent common ancestry with Bokeloh bat lyssavirus (BBLV) and Khujan virus (KHUV). EBLV-2 showed limited diversity compared to RABV and appears to be well adapted to its host bat species. The slow tempo of viral evolution was evident in the estimations of divergence times for EBLV-2: the current diversity was estimated to have built up during the last 2000 years, and EBLV-2 diverged from KHUV about 8000 years ago. In a phylogenetic tree of partial N gene sequences, the Finnish EBLV-2 strains clustered with strains from Central Europe, supporting the hypothesis that EBLV-2 circulating in Finland might have a Central European origin. The Finnish EBLV-2 strains and a Swiss strain were estimated to have diverged from other EBLV-2 strains during the last 1000 years, and the two Finnish strains appear to have evolved from a common ancestor during the last 200 years.

  15. F-rich strongly peraluminous A-type magmatism in the pre-Andean foreland Sierras Pampeanas, Argentina: Geochemical, geochronological, isotopic constraints and petrogenesis

    Science.gov (United States)

    Morales Cámera, Matías M.; Dahlquist, Juan A.; Basei, Miguel A. S.; Galindo, Carmen; da Costa Campos Neto, Mario; Facetti, Nicolás

    2017-04-01

    The petrogenetic nature of A-type granites is a controversial problem. The Vinquis batholith in the Sierras Pampeanas of Argentina contains unusual F-rich and strongly peraluminous A-type monzogranites. A new LA-MC-ICP-MS U-Pb zircon crystallization age of 355 ± 7 Ma indicates emplacement in latest Devonian or earliest Carboniferous time, overlapping with extensive metaluminous A-type magmatism in the area. The monzogranites have a restricted range of SiO2 content (71.5-74.8 %), they are poor in Ca (0.54-1.4% CaO) and rich in FeOt, with relatively high FeOt/(FeOt+MgO) values ranging from 0.77 to 0.86 (average = 0.80) Both [FeOt/ (FeOt+MgO)] vs. SiO2 and [(Na2O+K2O)-CaO] vs. SiO2 plots indicate ferroan and alkali-calcic signatures typical of A-type granitoids. The samples have MgO/TiO2 > 1.2 and are moderately enriched in total alkalis (average 8.18%), with high K2O/Na2O values of 1.40-2.24. The granites are strongly peraluminous, with ASI (molar Al2O3/[CaO + Na2O + K2O]) values of 1.2 to 1.3. The high P2O5 content (0.23-0.37%) is distinctive and close to values reported for other Paleozoic F-rich peraluminous A-type granites in the Sierras Pampeanas. They have moderate contents of high field strength elements (e.g., Zr, Nb, Th, Y, etc.) and moderately fractionated to flat REE patterns [(La/Yb)N in the range 4.8-19.6] showing significant negative Eu anomalies (Eu/Eu* = 0.41). Biotite has a distinctive composition, with relatively high Fe2 +/(Fe2 + + Mg) ratios (0.61-0.74) and high F (0.55-1.42 wt.%) content. Together with the whole-rock chemistry this may be useful in identifying strongly peraluminous A-type granites. In addition, the Rb/Sr vs. Th + Zr + Ce diagram may be an appropriate discriminant between metaluminous and peralkaline A-type granites, strongly peraluminous A-type granites and strongly peraluminous orogenic granites. The geochemical evidence indicates that differentiation of the granitic rocks occurred by mineral fractionation from a F

  16. A new lysozyme from the eastern oyster, Crassostrea virginica, and a possible evolutionary pathway for i-type lysozymes in bivalves from host defense to digestion

    Science.gov (United States)

    2010-01-01

    Background Lysozymes are enzymes that lyse bacterial cell walls, an activity widely used for host defense but also modified in some instances for digestion. The biochemical and evolutionary changes between these different functional forms has been well-studied in the c-type lysozymes of vertebrates, but less so in the i-type lysozymes prevalent in most invertebrate animals. Some bivalve molluscs possess both defensive and digestive lysozymes. Results We report a third lysozyme from the oyster Crassostrea virginica, cv-lysozyme 3. The chemical properties of cv-lysozyme 3 (including molecular weight, isoelectric point, basic amino acid residue number, and predicted protease cutting sites) suggest it represents a transitional form between lysozymes used for digestion and immunity. The cv-lysozyme 3 protein inhibited the growth of bacteria (consistent with a defensive function), but semi-quantitative RT-PCR suggested the gene was expressed mainly in digestive glands. Purified cv-lysozyme 3 expressed maximum muramidase activity within a range of pH (7.0 and 8.0) and ionic strength (I = 0.005-0.01) unfavorable for either cv-lysozyme 1 or cv-lysozyme 2 activities. The topology of a phylogenetic analysis of cv-lysozyme 3 cDNA (full length 663 bp, encoding an open reading frame of 187 amino acids) is also consistent with a transitional condition, as cv-lysozyme 3 falls at the base of a monophyletic clade of bivalve lysozymes identified from digestive glands. Rates of nonsynonymous substitution are significantly high at the base of this clade, consistent with an episode of positive selection associated with the functional transition from defense to digestion. Conclusion The pattern of molecular evolution accompanying the shift from defensive to digestive function in the i-type lysozymes of bivalves parallels those seen for c-type lysozymes in mammals and suggests that the lysozyme paralogs that enhance the range of physiological conditions for lysozyme activity may provide

  17. A new lysozyme from the eastern oyster, Crassostrea virginica, and a possible evolutionary pathway for i-type lysozymes in bivalves from host defense to digestion

    Directory of Open Access Journals (Sweden)

    Itoh Naoki

    2010-07-01

    Full Text Available Abstract Background Lysozymes are enzymes that lyse bacterial cell walls, an activity widely used for host defense but also modified in some instances for digestion. The biochemical and evolutionary changes between these different functional forms has been well-studied in the c-type lysozymes of vertebrates, but less so in the i-type lysozymes prevalent in most invertebrate animals. Some bivalve molluscs possess both defensive and digestive lysozymes. Results We report a third lysozyme from the oyster Crassostrea virginica, cv-lysozyme 3. The chemical properties of cv-lysozyme 3 (including molecular weight, isoelectric point, basic amino acid residue number, and predicted protease cutting sites suggest it represents a transitional form between lysozymes used for digestion and immunity. The cv-lysozyme 3 protein inhibited the growth of bacteria (consistent with a defensive function, but semi-quantitative RT-PCR suggested the gene was expressed mainly in digestive glands. Purified cv-lysozyme 3 expressed maximum muramidase activity within a range of pH (7.0 and 8.0 and ionic strength (I = 0.005-0.01 unfavorable for either cv-lysozyme 1 or cv-lysozyme 2 activities. The topology of a phylogenetic analysis of cv-lysozyme 3 cDNA (full length 663 bp, encoding an open reading frame of 187 amino acids is also consistent with a transitional condition, as cv-lysozyme 3 falls at the base of a monophyletic clade of bivalve lysozymes identified from digestive glands. Rates of nonsynonymous substitution are significantly high at the base of this clade, consistent with an episode of positive selection associated with the functional transition from defense to digestion. Conclusion The pattern of molecular evolution accompanying the shift from defensive to digestive function in the i-type lysozymes of bivalves parallels those seen for c-type lysozymes in mammals and suggests that the lysozyme paralogs that enhance the range of physiological conditions for

  18. Realism, Relativism, and Evolutionary Psychology

    NARCIS (Netherlands)

    Derksen, M.

    Against recent attempts to forge a reconciliation between constructionism and realism, I contend that, in psychology at least, stirring up conflict is a more fruitful strategy. To illustrate this thesis, I confront a school of psychology with strong realist leanings, evolutionary psychology, with

  19. Studies in evolutionary agroecology

    DEFF Research Database (Denmark)

    Wille, Wibke

    difference between optimal individual and optimal population performance increases with strong competition among individuals. Thus dense populations make ideal environments to exert forms of selection pressure deviating from natural selection. The first part of this study investigates the central hypothesis...... of Evolutionary Agroecology that the highest yielding individuals do not necessarily perform best as a population. The investment of resources into strategies and structures increasing individual competitive ability carries a cost. If a whole population consists of individuals investing resources to compete...... with each other, it will have a negative impact on the population performance. While high density results in strong competition, it also increases the potential for cooperation. The other aspect of this study has been to investigate the possibility of improving the yield and weed suppression potential...

  20. Computational evolutionary perception.

    Science.gov (United States)

    Hoffman, Donald D; Singh, Manish

    2012-01-01

    Marr proposed that human vision constructs "a true description of what is there". He argued that to understand human vision one must discover the features of the world it recovers and the constraints it uses in the process. Bayesian decision theory (BDT) is used in modem vision research as a probabilistic framework for understanding human vision along the lines laid out by Marr. Marr's contribution to vision research is substantial and justly influential. We propose, however, that evolution by natural selection does not, in general, favor perceptions that are true descriptions of the objective world. Instead, research with evolutionary games shows that perceptual systems tuned solely to fitness routinely outcompete those tuned to truth. Fitness functions depend not just on the true state of the world, but also on the organism, its state, and the type of action. Thus, fitness and truth are distinct. Natural selection depends only on expected fitness. It shapes perceptual systems to guide fitter behavior, not to estimate truth. To study perception in an evolutionary context, we introduce the framework of Computational Evolutionary Perception (CEP). We show that CEP subsumes BDT, and reinterprets BDT as evaluating expected fitness rather than estimating truth.

  1. Serum level of soluble urokinase-type plasminogen activator receptor is a strong and independent predictor of survival in human immunodeficiency virus infection

    DEFF Research Database (Denmark)

    Sidenius, N; Sier, CFM; Ullum, H

    2000-01-01

    Human immunodeficiency virus-1 (HIV-1) infection has been shown to result in up-regulation of the urokinase-type plasminogen activator receptor (uPAR/CD87) on leukocytes in vitro and in vivo. The objective of this study was to investigate whether this up-regulation is paralleled by higher serum...... that the serum suPAR level is a novel, strong, and independent predictor of survival in HIV-1 infection. This report is the first to demonstrate an important association between the plasminogen activator system and disease progression in HIV-1 infection....

  2. Multiple explanations in Darwinian evolutionary theory.

    Science.gov (United States)

    Bock, Walter J

    2010-03-01

    Variational evolutionary theory as advocated by Darwin is not a single theory, but a bundle of related but independent theories, namely: (a) variational evolution; (b) gradualism rather than large leaps; (c) processes of phyletic evolution and of speciation; (d) causes for the formation of varying individuals in populations and for the action of selective agents; and (e) all organisms evolved from a common ancestor. The first four are nomological-deductive explanations and the fifth is historical-narrative. Therefore evolutionary theory must be divided into nomological and historical theories which are both testable against objective empirical observations. To be scientific, historical evolutionary theories must be based on well corroborated nomological theories, both evolutionary and functional. Nomological and general historical evolutionary theories are well tested and must be considered as strongly corroborated scientific theories. Opponents of evolutionary theory are concerned only with historical evolutionary theories, having little interest in nomological theory. Yet given a well corroborated nomological evolutionary theory, historical evolutionary theories follow automatically. If understood correctly, both forms of evolutionary theories stand on their own as corroborated scientific theories and should not be labeled as facts.

  3. The Evolving Theory of Evolutionary Radiations.

    Science.gov (United States)

    Simões, M; Breitkreuz, L; Alvarado, M; Baca, S; Cooper, J C; Heins, L; Herzog, K; Lieberman, B S

    2016-01-01

    Evolutionary radiations have intrigued biologists for more than 100 years, and our understanding of the patterns and processes associated with these radiations continues to grow and evolve. Recently it has been recognized that there are many different types of evolutionary radiation beyond the well-studied adaptive radiations. We focus here on multifarious types of evolutionary radiations, paying special attention to the abiotic factors that might trigger diversification in clades. We integrate concepts such as exaptation, species selection, coevolution, and the turnover-pulse hypothesis (TPH) into the theoretical framework of evolutionary radiations. We also discuss other phenomena that are related to, but distinct from, evolutionary radiations that have relevance for evolutionary biology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Comparative evolutionary genomics of the HADH2 gene encoding Aβ-binding alcohol dehydrogenase/17β-hydroxysteroid dehydrogenase type 10 (ABAD/HSD10

    Directory of Open Access Journals (Sweden)

    Fernandes Pedro A

    2006-08-01

    Full Text Available Abstract Background The Aβ-binding alcohol dehydrogenase/17β-hydroxysteroid dehydrogenase type 10 (ABAD/HSD10 is an enzyme involved in pivotal metabolic processes and in the mitochondrial dysfunction seen in the Alzheimer's disease. Here we use comparative genomic analyses to study the evolution of the HADH2 gene encoding ABAD/HSD10 across several eukaryotic species. Results Both vertebrate and nematode HADH2 genes showed a six-exon/five-intron organization while those of the insects had a reduced and varied number of exons (two to three. Eutherian mammal HADH2 genes revealed some highly conserved noncoding regions, which may indicate the presence of functional elements, namely in the upstream region about 1 kb of the transcription start site and in the first part of intron 1. These regions were also conserved between Tetraodon and Fugu fishes. We identified a conserved alternative splicing event between human and dog, which have a nine amino acid deletion, causing the removal of the strand βF. This strand is one of the seven strands that compose the core β-sheet of the Rossman fold dinucleotide-binding motif characteristic of the short chain dehydrogenase/reductase (SDR family members. However, the fact that the substrate binding cleft residues are retained and the existence of a shared variant between human and dog suggest that it might be functional. Molecular adaptation analyses across eutherian mammal orthologues revealed the existence of sites under positive selection, some of which being localized in the substrate-binding cleft and in the insertion 1 region on loop D (an important region for the Aβ-binding to the enzyme. Interestingly, a higher than expected number of nonsynonymous substitutions were observed between human/chimpanzee and orangutan, with six out of the seven amino acid replacements being under molecular adaptation (including three in loop D and one in the substrate binding loop. Conclusion Our study revealed that HADH

  5. Evolutionary inevitability of sexual antagonism.

    Science.gov (United States)

    Connallon, Tim; Clark, Andrew G

    2014-02-07

    Sexual antagonism, whereby mutations are favourable in one sex and disfavourable in the other, is common in natural populations, yet the root causes of sexual antagonism are rarely considered in evolutionary theories of adaptation. Here, we explore the evolutionary consequences of sex-differential selection and genotype-by-sex interactions for adaptation in species with separate sexes. We show that sexual antagonism emerges naturally from sex differences in the direction of selection on phenotypes expressed by both sexes or from sex-by-genotype interactions affecting the expression of such phenotypes. Moreover, modest sex differences in selection or genotype-by-sex effects profoundly influence the long-term evolutionary trajectories of populations with separate sexes, as these conditions trigger the evolution of strong sexual antagonism as a by-product of adaptively driven evolutionary change. The theory demonstrates that sexual antagonism is an inescapable by-product of adaptation in species with separate sexes, whether or not selection favours evolutionary divergence between males and females.

  6. Early Observations of the Type Ia Supernova iPTF 16abc: A Case of Interaction with Nearby, Unbound Material and/or Strong Ejecta Mixing

    Science.gov (United States)

    Miller, A. A.; Cao, Y.; Piro, A. L.; Blagorodnova, N.; Bue, B. D.; Cenko, S. B.; Dhawan, S.; Ferretti, R.; Fox, O. D.; Fremling, C.; Goobar, A.; Howell, D. A.; Hosseinzadeh, G.; Kasliwal, M. M.; Laher, R. R.; Lunnan, R.; Masci, F. J.; McCully, C.; Nugent, P. E.; Sollerman, J.; Taddia, F.; Kulkarni, S. R.

    2018-01-01

    Early observations of Type Ia supernovae (SNe Ia) provide a unique probe of their progenitor systems and explosion physics. Here we report the intermediate Palomar Transient Factory (iPTF) discovery of an extraordinarily young SN Ia, iPTF 16abc. By fitting a power law to our early light curve, we infer that first light for the SN, that is, when the SN could have first been detected by our survey, occurred only 0.15{+/- }0.070.15 days before our first detection. In the ∼24 hr after discovery, iPTF 16abc rose by ∼2 mag, featuring a near-linear rise in flux for ≳ 3 days. Early spectra show strong C II absorption, which disappears after ∼7 days. Unlike the extensively observed Type Ia SN 2011fe, the {(B-V)}0 colors of iPTF 16abc are blue and nearly constant in the days after explosion. We show that our early observations of iPTF 16abc cannot be explained by either SN shock breakout and the associated, subsequent cooling or the SN ejecta colliding with a stellar companion. Instead, we argue that the early characteristics of iPTF 16abc, including (i) the rapid, near-linear rise, (ii) the nonevolving blue colors, and (iii) the strong C II absorption, are the result of either ejecta interaction with nearby, unbound material or vigorous mixing of radioactive 56Ni in the SN ejecta, or a combination of the two. In the next few years, dozens of very young normal SNe Ia will be discovered, and observations similar to those presented here will constrain the white dwarf explosion mechanism.

  7. Precursory strong-signal characteristics of the convective clouds of the Central Tibetan Plateau detected by radar echoes with respect to the evolutionary processes of an eastward-moving heavy rainstorm belt in the Yangtze River Basin

    Science.gov (United States)

    Zhao, Yang; Xu, Xiangde; Ruan, Zheng; Chen, Bin; Wang, Fang

    2018-03-01

    The integrated analysis of the data from a C-band frequency-modulated continuous-wave (C-FMCW) radar site in Naqu obtained during a rainstorm over the middle and lower reaches of the Yangtze River and the data concerning the three-dimensional structure of the circulation of the precipitation system that occurred over the lower reaches of the Yangtze River Basin during the Third Tibetan Plateau (TP) Atmospheric Experiment from August 15th to 19th, 2014, was carried out. The changes in the echo intensity at the C-FMCW radar site in Naqu were of regional indicative significance for the characteristics of the whole-layer apparent heat source Q1 in local areas and the region of the adjacent river source area, including the Yangtze River, Yellow River, and Lancang River (hereinafter referred to as the "source area of three rivers"), as well as to the vertical speeds due to the development of convection. This study indicates that the C-FMCW radar echo intensity of the plateau convection zone and the related power structures of the coupled dipole circulations in the middle layer of the atmosphere, as well as in the upper atmospheric level divergence and lower atmospheric level convergence, are important stimuli for convective clouds in this region. Furthermore, these radar data provided a physical image of the development and maintenance mechanisms of an eastward-moving heavy rainstorm belt. This study also shows that changes in the echo intensities at the C-FMCW radar site of Naqu can provide strong signals related to heavy rainstorm processes in the upper reaches of the Yangtze River.

  8. Evolutionary Aesthetics and Print Advertising

    Directory of Open Access Journals (Sweden)

    Kamil Luczaj

    2015-06-01

    Full Text Available The article analyzes the extent to which predictions based on the theory of evolutionary aesthetics are utilized by the advertising industry. The purpose of a comprehensive content analysis of print advertising is to determine whether the items indicated by evolutionists such as animals, flowers, certain types of landscapes, beautiful humans, and some colors are part of real advertising strategies. This article has shown that many evolutionary hypotheses (although not all of them are supported by empirical data. Along with these hypotheses, some inferences from Bourdieu’s cultural capital theory were tested. It turned out that advertising uses both biological schemata and cultural patterns to make an image more likable.

  9. Guest Induced Strong Cooperative One- and Two-Step Spin Transitions in Highly Porous Iron(II) Hofmann-Type Metal-Organic Frameworks.

    Science.gov (United States)

    Piñeiro-López, Lucı A; Valverde-Muñoz, Francisco Javier; Seredyuk, Maksym; Muñoz, M Carmen; Haukka, Matti; Real, José Antonio

    2017-06-19

    The synthesis, crystal structure, magnetic, calorimetric, and Mössbauer studies of a series of new Hofmann-type spin crossover (SCO) metal-organic frameworks (MOFs) is reported. The new SCO-MOFs arise from self-assembly of Fe II , bis(4-pyridyl)butadiyne (bpb), and [Ag(CN) 2 ] - or [M II (CN) 4 ] 2- (M II = Ni, Pd). Interpenetration of four identical 3D networks with α-Po topology are obtained for {Fe(bpb)[Ag I (CN) 2 ] 2 } due to the length of the rod-like bismonodentate bpb and [Ag(CN) 2 ] - ligands. The four networks are tightly packed and organized in two subsets orthogonally interpenetrated, while the networks in each subset display parallel interpenetration. This nonporous material undergoes a very incomplete SCO, which is rationalized from its intricate structure. In contrast, the single network Hofmann-type MOFs {Fe(bpb)[M II (CN) 4 ]}·nGuest (M II = Ni, Pd) feature enhanced porosity and display complete one-step or two-step cooperative SCO behaviors when the pores are filled with two molecules of nitrobenzene or naphthalene that interact strongly with the pyridyl and cyano moieties of the bpb ligands via π-π stacking. The lack of these guest molecules favors stabilization of the high-spin state in the whole range of temperatures. However, application of hydrostatic pressure induces one- and two-step SCO.

  10. Attractive evolutionary equilibria

    NARCIS (Netherlands)

    Joosten, Reinoud A.M.G.; Roorda, Berend

    2011-01-01

    We present attractiveness, a refinement criterion for evolutionary equilibria. Equilibria surviving this criterion are robust to small perturbations of the underlying payoff system or the dynamics at hand. Furthermore, certain attractive equilibria are equivalent to others for certain evolutionary

  11. Excision Efficiency Is Not Strongly Coupled to Transgenic Rate: Cell Type-Dependent Transposition Efficiency of Sleeping Beauty and piggyBac DNA Transposons

    Science.gov (United States)

    Kolacsek, Orsolya; Erdei, Zsuzsa; Apáti, Ágota; Sándor, Sára; Izsvák, Zsuzsanna; Ivics, Zoltán; Sarkadi, Balázs

    2014-01-01

    Abstract The Sleeping Beauty (SB) and piggyBac (PB) DNA transposons represent an emerging new gene delivery technology, potentially suitable for human gene therapy applications. Previous studies pointed to important differences between these transposon systems, depending on the cell types examined and the methodologies applied. However, efficiencies cannot always be compared because of differences in applications. In addition, “overproduction inhibition,” a phenomenon believed to be a characteristic of DNA transposons, can remarkably reduce the overall transgenic rate, emphasizing the importance of transposase dose applied. Therefore, because of lack of comprehensive analysis, researchers are forced to optimize the technology for their own “in-house” platforms. In this study, we investigated the transposition of several SB (SB11, SB32, SB100X) and PB (mPB and hyPB) variants in various cell types at three levels: comparing the excision efficiency of the reaction by real-time PCR, testing the overall transgenic rate by detecting cells with stable integrations, and determining the average copy number when using different transposon systems and conditions. We concluded that high excision activity is not always followed by a higher transgenic rate, as exemplified by the hyperactive transposases, indicating that the excision and the integration steps of transposition are not strongly coupled as previously thought. In general, all levels of transposition show remarkable differences depending on the transposase used and cell lines examined, being the least efficient in human embryonic stem cells (hESCs). In spite of the comparably low activity in those special cell types, the hyperactive SB100X and hyPB systems could be used in hESCs with similar transgenic efficiency and with reasonably low (2–3) transgene copy numbers, indicating their potential applicability for gene therapy purposes in the future. PMID:25045962

  12. Evolutionary Biology Today

    Indian Academy of Sciences (India)

    Evolutionary Biology Today - The Domain of Evolutionary Biology ... Keywords. Evolution; natural selection; biodiversity; fitness; adaptation. Author Affiliations. Amitabh Joshi1. Evolutionary and Organismal Biology Unit Jawaharlal Nehru Centre for Advanced Scientific Research P.Box 6436, Jakkur Bangalore 560 065, India.

  13. Snake venomics of Crotalus tigris: the minimalist toxin arsenal of the deadliest Nearctic rattlesnake venom. Evolutionary Clues for generating a pan-specific antivenom against crotalid type II venoms [corrected].

    Science.gov (United States)

    Calvete, Juan J; Pérez, Alicia; Lomonte, Bruno; Sánchez, Elda E; Sanz, Libia

    2012-02-03

    We report the proteomic and antivenomic characterization of Crotalus tigris venom. This venom exhibits the highest lethality for mice among rattlesnakes and the simplest toxin proteome reported to date. The venom proteome of C. tigris comprises 7-8 gene products from 6 toxin families; the presynaptic β-neurotoxic heterodimeric PLA(2), Mojave toxin, and two serine proteinases comprise, respectively, 66 and 27% of the C. tigris toxin arsenal, whereas a VEGF-like protein, a CRISP molecule, a medium-sized disintegrin, and 1-2 PIII-SVMPs each represent 0.1-5% of the total venom proteome. This toxin profile really explains the systemic neuro- and myotoxic effects observed in envenomated animals. In addition, we found that venom lethality of C. tigris and other North American rattlesnake type II venoms correlates with the concentration of Mojave toxin A-subunit, supporting the view that the neurotoxic venom phenotype of crotalid type II venoms may be described as a single-allele adaptation. Our data suggest that the evolutionary trend toward neurotoxicity, which has been also reported for the South American rattlesnakes, may have resulted by pedomorphism. The ability of an experimental antivenom to effectively immunodeplete proteins from the type II venoms of C. tigris, Crotalus horridus , Crotalus oreganus helleri, Crotalus scutulatus scutulatus, and Sistrurus catenatus catenatus indicated the feasibility of generating a pan-American anti-Crotalus type II antivenom, suggested by the identification of shared evolutionary trends among South and North American Crotalus species.

  14. The evolutionary value of recombination is constrained by genome modularity.

    Directory of Open Access Journals (Sweden)

    Darren P Martin

    2005-10-01

    Full Text Available Genetic recombination is a fundamental evolutionary mechanism promoting biological adaptation. Using engineered recombinants of the small single-stranded DNA plant virus, Maize streak virus (MSV, we experimentally demonstrate that fragments of genetic material only function optimally if they reside within genomes similar to those in which they evolved. The degree of similarity necessary for optimal functionality is correlated with the complexity of intragenomic interaction networks within which genome fragments must function. There is a striking correlation between our experimental results and the types of MSV recombinants that are detectable in nature, indicating that obligatory maintenance of intragenome interaction networks strongly constrains the evolutionary value of recombination for this virus and probably for genomes in general.

  15. The Evolutionary Value of Recombination Is Constrained by Genome Modularity.

    Directory of Open Access Journals (Sweden)

    2005-10-01

    Full Text Available Genetic recombination is a fundamental evolutionary mechanism promoting biological adaptation. Using engineered recombinants of the small single-stranded DNA plant virus, Maize streak virus (MSV, we experimentally demonstrate that fragments of genetic material only function optimally if they reside within genomes similar to those in which they evolved. The degree of similarity necessary for optimal functionality is correlated with the complexity of intragenomic interaction networks within which genome fragments must function. There is a striking correlation between our experimental results and the types of MSV recombinants that are detectable in nature, indicating that obligatory maintenance of intragenome interaction networks strongly constrains the evolutionary value of recombination for this virus and probably for genomes in general.

  16. Osteopontin is a strong predictor of incipient diabetic nephropathy, cardiovascular disease, and all-cause mortality in patients with type 1 diabetes.

    Science.gov (United States)

    Gordin, Daniel; Forsblom, Carol; Panduru, Nicolae M; Thomas, Merlin C; Bjerre, Mette; Soro-Paavonen, Aino; Tolonen, Nina; Sandholm, Niina; Flyvbjerg, Allan; Harjutsalo, Valma; Groop, Per-Henrik

    2014-09-01

    Osteopontin (OPN) is a multifunctional protein suggested to be a player in the arterial disease of patients with type 2 diabetes. However, its role for complications in patients with type 1 diabetes (T1D) is unknown. We therefore investigated the associations between OPN and diabetic vascular complications and all-cause mortality in patients with T1D. Serum OPN was measured in 2,145 adults with T1D without end-stage renal disease (ESRD; dialysis or transplantation) as part of the Finnish Diabetic Nephropathy (FinnDiane) Study. Data on renal status, cardiovascular disease (CVD), and all-cause mortality during follow-up were verified from medical files, hospital discharge registries, and the Finnish National Death Registry, respectively. The median follow-up time was 10.5 (interquartile range 8.9-11.8) years. Serum OPN was higher at baseline in patients who developed incident microalbuminuria (16.0 ± 0.9 vs. 14.1 ± 0.2 µg/L; P = 0.04), progressed to ESRD (28.3 ± 1.7 vs. 15.4 ± 0.2 µg/L; P risk factors. Even after calculating reclassification indexes, OPN was predictive of CVD and all-cause mortality beyond the Framingham risk score covariates and hs-CRP. Serum OPN is a strong predictor of incipient diabetic nephropathy, a first-ever CVD event, and all-cause mortality in patients with T1D. Serum OPN may be of clinical significance for the risk prediction of CVD events in patients with T1D. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  17. Total and free testosterone concentrations are strongly influenced by age and central obesity in men with type 1 and type 2 diabetes but correlate weakly with symptoms of androgen deficiency and diabetes-related quality of life.

    Science.gov (United States)

    Biswas, Mousumi; Hampton, David; Newcombe, Robert G; Rees, D Aled

    2012-05-01

    Testosterone levels are commonly lowered in men with diabetes, but it is unclear how these relate to symptoms of hypogonadism and quality of life. We sought to investigate the relationship between testosterone levels, symptoms of androgen deficiency, erectile function and quality of life in men with type 1 and type 2 diabetes. Cross-sectional study of 115 men with type 2 diabetes, 93 men with type 1 diabetes and 121 healthy controls. Total, bioavailable and free testosterone levels were measured or calculated by Vermuelen's formula. Quality of life and symptom scores were assessed by the Audit of Diabetes Dependent Quality of Life (ADDQoL), androgen deficiency in the aging male (ADAM) and International Index of Erectile Function (IIEF) questionnaires. Forty-five and sixty-one per cent of men with type 2 diabetes had low total and calculated free testosterone (CFT) levels, respectively. Total testosterone (TT) levels were not lowered in men with type 1 diabetes, but 32% had low CFT. After adjustment for age and waist circumference, only CFT in men with type 2 diabetes (-0·037 nm, 95% CI -0·075 to -0·0003, P = 0.048) remained lowered compared with controls. CFT correlated weakly with ADAM (r = -0·26, 95% CI -0.42 to -0·08, P = 0·006), IIEF (r = 0.19, 95% CI 0.01-0.37, P = 0.042) and ADDQoL (r = 0.21, 95% CI 0·03 to 0·38, P = 0·022) scores in men with type 2, but not type 1 diabetes. Age exerted the predominant effect on erectile function in both groups, in a model incorporating age, testosterone level and complications. Testosterone levels are strongly affected by age and central obesity in men with type 1 and type 2 diabetes but correlate weakly with symptoms of androgen deficiency and erectile function. Testosterone levels do not appear to be a major determinant of quality of life in patients with diabetes. © 2012 Blackwell Publishing Ltd.

  18. Serum aspirin esterase is strongly associated with glucose and lipids in healthy subjects: different association patterns in subjects with type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Kotani Kazuhiko

    2010-07-01

    Full Text Available Abstract Background Aspirin esterase (AE activity can account for part of aspirin pharmacokinetics in the circulation, possibly being associated with the impairment of aspirin effectiveness as an inhibitor of platelet aggregation. Aims The study was aimed at investigating the correlations of serum AE activity with cholinesterase (ChE and metabolic variables in healthy subjects in comparison to subjects with type 2 diabetes mellitus (T2DM. Methods In cardiovascular disease-free T2DM subjects and healthy controls, the AE activity levels and/or the correlation patterns between AE and the other variables were analyzed. Results Neither AE nor ChE activities were higher in the subjects with T2DM. Serum AE activity strongly correlated with ChE as well as glucose/lipids variables such as total cholesterol and triglyceride in healthy subjects, while the correlations between AE and glucose/lipids variables were not present in T2DM subjects. Conclusions These data may reflect the pathophysiological changes between healthy and T2DM subjects. Our data may thus provide the basis for future studies to unravel the mechanisms.

  19. Psychological trauma symptoms and Type 2 diabetes prevalence, glucose control, and treatment modality among American Indians in the Strong Heart Family Study.

    Science.gov (United States)

    Jacob, Michelle M; Gonzales, Kelly L; Calhoun, Darren; Beals, Janette; Muller, Clemma Jacobsen; Goldberg, Jack; Nelson, Lonnie; Welty, Thomas K; Howard, Barbara V

    2013-01-01

    The aims of this paper are to examine the relationship between psychological trauma symptoms and Type 2 diabetes prevalence, glucose control, and treatment modality among 3776 American Indians in Phase V of the Strong Heart Family Study. This cross-sectional analysis measured psychological trauma symptoms using the National Anxiety Disorder Screening Day instrument, diabetes by American Diabetes Association criteria, and treatment modality by four categories: no medication, oral medication only, insulin only, or both oral medication and insulin. We used binary logistic regression to evaluate the association between psychological trauma symptoms and diabetes prevalence. We used ordinary least squares regression to evaluate the association between psychological trauma symptoms and glucose control. We used binary logistic regression to model the association of psychological trauma symptoms with treatment modality. Neither diabetes prevalence (22%-31%; p=0.19) nor control (8.0-8.6; p=0.25) varied significantly by psychological trauma symptoms categories. However, diabetes treatment modality was associated with psychological trauma symptoms categories, as people with greater burden used either no medication, or both oral and insulin medications (odds ratio=3.1, ppsychological trauma symptoms suggests future research investigate patient and provider treatment decision making. © 2013.

  20. Identification and quantification of the caproic acid-producing bacterium Clostridium kluyveri in the fermentation of pit mud used for Chinese strong-aroma type liquor production.

    Science.gov (United States)

    Hu, Xiao-Long; Du, Hai; Xu, Yan

    2015-12-02

    Chinese strong-aroma type liquor (CSAL) is a popular distilled alcoholic beverage in China. It is produced by a complex fermentation process that is conducted in pits in the ground. Ethyl caproate is a key flavor compound in CSAL and is thought to originate from caproic acid produced by Clostridia inhabiting the fermentation pit mud. However, the particular species of Clostridium associated with this production are poorly understood and problematic to quantify by culturing. In this study, a total of 28 closest relatives including 15 Clostridia and 8 Bacilli species in pit muds from three CSAL distilleries, were detected by culture-dependent and -independent methods. Among them, Clostridium kluyveri was identified as the main producer of caproic acid. One representative strain C. kluyveri N6 could produce caproic, butyric and octanoic acids and their corresponding ethyl esters, contributing significantly to CSAL flavor. A real time quantitative PCR assay of C. kluyveri in pit muds developed showed that a concentration of 1.79×10(7) 16S rRNA gene copies/g pit mud in LZ-old pit was approximately six times higher than that in HLM and YH pits and sixty times higher than that in LZ-new pit respectively. This method can be used to improve the management of pit mud microbiology and its impact on CSAL quality. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Reduced larval feeding rate is a strong evolutionary correlate of ...

    Indian Academy of Sciences (India)

    To answer the question, are preadult development time and larval feeding rate ... Keywords. life-history evolution; development time; larval feeding rate; competition; tradeoffs; Drosophila melanogaster. Journal of Genetics, Vol. 85, No ..... financial assistance in the form of a senior research fellowship. N.A. thanks Jawaharlal ...

  2. Reduced larval feeding rate is a strong evolutionary correlate of ...

    Indian Academy of Sciences (India)

    2001) was an arte- fact of extreme directional selection for rapid development that led to changes in the correlational structure of develop- ment time, larval feeding rate, dry weight at eclosion, and preadult survivorship. A positive genetic correlation between larval feeding rate and development time in the control pop-.

  3. Remembering the evolutionary Freud.

    Science.gov (United States)

    Young, Allan

    2006-03-01

    Throughout his career as a writer, Sigmund Freud maintained an interest in the evolutionary origins of the human mind and its neurotic and psychotic disorders. In common with many writers then and now, he believed that the evolutionary past is conserved in the mind and the brain. Today the "evolutionary Freud" is nearly forgotten. Even among Freudians, he is regarded to be a red herring, relevant only to the extent that he diverts attention from the enduring achievements of the authentic Freud. There are three ways to explain these attitudes. First, the evolutionary Freud's key work is the "Overview of the Transference Neurosis" (1915). But it was published at an inopportune moment, forty years after the author's death, during the so-called "Freud wars." Second, Freud eventually lost interest in the "Overview" and the prospect of a comprehensive evolutionary theory of psychopathology. The publication of The Ego and the Id (1923), introducing Freud's structural theory of the psyche, marked the point of no return. Finally, Freud's evolutionary theory is simply not credible. It is based on just-so stories and a thoroughly discredited evolutionary mechanism, Lamarckian use-inheritance. Explanations one and two are probably correct but also uninteresting. Explanation number three assumes that there is a fundamental difference between Freud's evolutionary narratives (not credible) and the evolutionary accounts of psychopathology that currently circulate in psychiatry and mainstream journals (credible). The assumption is mistaken but worth investigating.

  4. Core principles of evolutionary medicine: A Delphi study.

    Science.gov (United States)

    Grunspan, Daniel Z; Nesse, Randolph M; Barnes, M Elizabeth; Brownell, Sara E

    2018-01-01

    Evolutionary medicine is a rapidly growing field that uses the principles of evolutionary biology to better understand, prevent and treat disease, and that uses studies of disease to advance basic knowledge in evolutionary biology. Over-arching principles of evolutionary medicine have been described in publications, but our study is the first to systematically elicit core principles from a diverse panel of experts in evolutionary medicine. These principles should be useful to advance recent recommendations made by The Association of American Medical Colleges and the Howard Hughes Medical Institute to make evolutionary thinking a core competency for pre-medical education. The Delphi method was used to elicit and validate a list of core principles for evolutionary medicine. The study included four surveys administered in sequence to 56 expert panelists. The initial open-ended survey created a list of possible core principles; the three subsequent surveys winnowed the list and assessed the accuracy and importance of each principle. Fourteen core principles elicited at least 80% of the panelists to agree or strongly agree that they were important core principles for evolutionary medicine. These principles over-lapped with concepts discussed in other articles discussing key concepts in evolutionary medicine. This set of core principles will be helpful for researchers and instructors in evolutionary medicine. We recommend that evolutionary medicine instructors use the list of core principles to construct learning goals. Evolutionary medicine is a young field, so this list of core principles will likely change as the field develops further.

  5. High-order epistasis shapes evolutionary trajectories.

    Science.gov (United States)

    Sailer, Zachary R; Harms, Michael J

    2017-05-01

    High-order epistasis-where the effect of a mutation is determined by interactions with two or more other mutations-makes small, but detectable, contributions to genotype-fitness maps. While epistasis between pairs of mutations is known to be an important determinant of evolutionary trajectories, the evolutionary consequences of high-order epistasis remain poorly understood. To determine the effect of high-order epistasis on evolutionary trajectories, we computationally removed high-order epistasis from experimental genotype-fitness maps containing all binary combinations of five mutations. We then compared trajectories through maps both with and without high-order epistasis. We found that high-order epistasis strongly shapes the accessibility and probability of evolutionary trajectories. A closer analysis revealed that the magnitude of epistasis, not its order, predicts is effects on evolutionary trajectories. We further find that high-order epistasis makes it impossible to predict evolutionary trajectories from the individual and paired effects of mutations. We therefore conclude that high-order epistasis profoundly shapes evolutionary trajectories through genotype-fitness maps.

  6. Fundamental aspects related to batch and fixed-bed sulfate sorption by the macroporous type 1 strong base ion exchange resin Purolite A500.

    Science.gov (United States)

    Guimarães, Damaris; Leão, Versiane A

    2014-12-01

    Acid mine drainage is a natural process occurring when sulfide minerals such as pyrite are exposed to water and oxygen. The bacterially catalyzed oxidation of pyrite is particularly common in coal mining operations and usually results in a low-pH water polluted with toxic metals and sulfate. Although high sulfate concentrations can be reduced by gypsum precipitation, removing lower concentrations (below 1200 mg/L) remains a challenge. Therefore, this work sought to investigate the application of ion exchange resins for sulfate sorption. The macroporous type 1 strong base IX resin Purolite A500 was selected for bath and fixed-bed sorption experiments using synthetic sulfate solutions. Equilibrium experiments showed that sulfate loading on the resin can be described by the Langmuir isotherm with a maximum uptake of 59 mg mL-resin(-1). The enthalpy of sorption was determined as +2.83 kJ mol(-1), implying an endothermic physisorption process that occurred with decreasing entropy (-15.5 J mol(-1).K(-1)). Fixed-bed experiments were performed at different bed depths, flow rates, and initial sulfate concentrations. The Miura and Hashimoto model predicted a maximum bed loading of 25-30 g L-bed(-1) and indicated that both film diffusion (3.2 × 10(-3) cm s(-1) to 22.6 × 10(-3) cm s(-1)) and surface diffusion (1.46 × 10(-7) cm(2) s(-1) to 5.64 × 10(-7) cm(2) s(-1)) resistances control the sorption process. It was shown that IX resins are an alternative for the removal of sulfate from mine waters; they ensure very low residual concentrations, particularly in effluents where the sulfate concentration is below the gypsum solubility threshold. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Evolutionary Biology Today

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 2. Evolutionary Biology Today - What do Evolutionary Biologists do? Amitabh Joshi. Series Article Volume 8 Issue 2 February 2003 pp 6-18. Fulltext. Click here to view fulltext PDF. Permanent link:

  8. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 9. Evolutionary Stable Strategy: Application of Nash Equilibrium in Biology. General ... Using some examples of classical games, we show how evolutionary game theory can help understand behavioural decisions of animals.

  9. Evolutionary Biology Today

    Indian Academy of Sciences (India)

    Amitabh Joshi studies and teaches evolutionary genetics and population ecology at the Jawaharlal. Nehru Centre for Advanced. Scientific Research,. Bangalore. His current research interests are in life- history evolution, the evolutionary genetics of biological clocks, and small population and meta population dynamics.

  10. Methodological problems in evolutionary biology. XII. Against evolutionary ethics.

    NARCIS (Netherlands)

    vd Steen, W.J.

    1999-01-01

    Evolutionary ethics has recently become popular again. Some of its representatives elaborate new attempts to derive ethics from evolutionary biology. The attempts, like previous ones, fail because they commit the naturalistic fallacy. Premises from evolutionary biology together with normative

  11. Evolutionary dynamics of group formation.

    Science.gov (United States)

    Javarone, Marco Alberto; Marinazzo, Daniele

    2017-01-01

    Group formation is a quite ubiquitous phenomenon across different animal species, whose individuals cluster together forming communities of diverse size. Previous investigations suggest that, in general, this phenomenon might have similar underlying reasons across the interested species, despite genetic and behavioral differences. For instance improving the individual safety (e.g. from predators), and increasing the probability to get food resources. Remarkably, the group size might strongly vary from species to species, e.g. shoals of fishes and herds of lions, and sometimes even within the same species, e.g. tribes and families in human societies. Here we build on previous theories stating that the dynamics of group formation may have evolutionary roots, and we explore this fascinating hypothesis from a purely theoretical perspective, with a model using the framework of Evolutionary Game Theory. In our model we hypothesize that homogeneity constitutes a fundamental ingredient in these dynamics. Accordingly, we study a population that tries to form homogeneous groups, i.e. composed of similar agents. The formation of a group can be interpreted as a strategy. Notably, agents can form a group (receiving a 'group payoff'), or can act individually (receiving an 'individual payoff'). The phase diagram of the modeled population shows a sharp transition between the 'group phase' and the 'individual phase', characterized by a critical 'individual payoff'. Our results then support the hypothesis that the phenomenon of group formation has evolutionary roots.

  12. Guiding deployment of resistance in cereals using evolutionary principles.

    Science.gov (United States)

    Burdon, Jeremy J; Barrett, Luke G; Rebetzke, Greg; Thrall, Peter H

    2014-06-01

    Genetically controlled resistance provides plant breeders with an efficient means of controlling plant disease, but this approach has been constrained by practical difficulties associated with combining many resistance genes together and strong evolutionary responses from pathogen populations leading to subsequent resistance breakdown. However, continuing advances in molecular marker technologies are revolutionizing the ability to rapidly and reliably manipulate resistances of all types - major gene, adult plant and quantitative resistance loci singly or multiply into individual host lines. Here, we argue that these advances provide major opportunities to deliberately design deployment strategies in cereals that can take advantage of the evolutionary pressures faced by target pathogens. Different combinations of genes deployed either within single host individuals or between different individuals within or among crops, can be used to reduce the size of pathogen populations and generate patterns of disruptive selection. This will simultaneously limit immediate epidemic development and reduce the probability of subsequent evolutionary change in the pathogen for broader infectivity or increased aggressiveness. The same general principles are relevant to the control of noncereal diseases, but the most efficacious controls will vary reflecting the range of genetic options available and their fit with specific ecology and life-history combinations.

  13. Part E: Evolutionary Computation

    DEFF Research Database (Denmark)

    2015-01-01

    of Computational Intelligence. First, comprehensive surveys of genetic algorithms, genetic programming, evolution strategies, parallel evolutionary algorithms are presented, which are readable and constructive so that a large audience might find them useful and – to some extent – ready to use. Some more general...... evolutionary algorithms, such as memetic algorithms, which have emerged as a very promising tool for solving many real-world problems in a multitude of areas of science and technology. Moreover, parallel evolutionary combinatorial optimization has been presented. Search operators, which are crucial in all...

  14. Evolutionary Mechanisms for Loneliness

    Science.gov (United States)

    Cacioppo, John T.; Cacioppo, Stephanie; Boomsma, Dorret I.

    2013-01-01

    Robert Weiss (1973) conceptualized loneliness as perceived social isolation, which he described as a gnawing, chronic disease without redeeming features. On the scale of everyday life, it is understandable how something as personally aversive as loneliness could be regarded as a blight on human existence. However, evolutionary time and evolutionary forces operate at such a different scale of organization than we experience in everyday life that personal experience is not sufficient to understand the role of loneliness in human existence. Research over the past decade suggests a very different view of loneliness than suggested by personal experience, one in which loneliness serves a variety of adaptive functions in specific habitats. We review evidence on the heritability of loneliness and outline an evolutionary theory of loneliness, with an emphasis on its potential adaptive value in an evolutionary timescale. PMID:24067110

  15. Eco-evolutionary feedbacks, adaptive dynamics and evolutionary rescue theory

    Science.gov (United States)

    Ferriere, Regis; Legendre, Stéphane

    2013-01-01

    Adaptive dynamics theory has been devised to account for feedbacks between ecological and evolutionary processes. Doing so opens new dimensions to and raises new challenges about evolutionary rescue. Adaptive dynamics theory predicts that successive trait substitutions driven by eco-evolutionary feedbacks can gradually erode population size or growth rate, thus potentially raising the extinction risk. Even a single trait substitution can suffice to degrade population viability drastically at once and cause ‘evolutionary suicide’. In a changing environment, a population may track a viable evolutionary attractor that leads to evolutionary suicide, a phenomenon called ‘evolutionary trapping’. Evolutionary trapping and suicide are commonly observed in adaptive dynamics models in which the smooth variation of traits causes catastrophic changes in ecological state. In the face of trapping and suicide, evolutionary rescue requires that the population overcome evolutionary threats generated by the adaptive process itself. Evolutionary repellors play an important role in determining how variation in environmental conditions correlates with the occurrence of evolutionary trapping and suicide, and what evolutionary pathways rescue may follow. In contrast with standard predictions of evolutionary rescue theory, low genetic variation may attenuate the threat of evolutionary suicide and small population sizes may facilitate escape from evolutionary traps. PMID:23209163

  16. Eco-evolutionary feedbacks, adaptive dynamics and evolutionary rescue theory.

    Science.gov (United States)

    Ferriere, Regis; Legendre, Stéphane

    2013-01-19

    Adaptive dynamics theory has been devised to account for feedbacks between ecological and evolutionary processes. Doing so opens new dimensions to and raises new challenges about evolutionary rescue. Adaptive dynamics theory predicts that successive trait substitutions driven by eco-evolutionary feedbacks can gradually erode population size or growth rate, thus potentially raising the extinction risk. Even a single trait substitution can suffice to degrade population viability drastically at once and cause 'evolutionary suicide'. In a changing environment, a population may track a viable evolutionary attractor that leads to evolutionary suicide, a phenomenon called 'evolutionary trapping'. Evolutionary trapping and suicide are commonly observed in adaptive dynamics models in which the smooth variation of traits causes catastrophic changes in ecological state. In the face of trapping and suicide, evolutionary rescue requires that the population overcome evolutionary threats generated by the adaptive process itself. Evolutionary repellors play an important role in determining how variation in environmental conditions correlates with the occurrence of evolutionary trapping and suicide, and what evolutionary pathways rescue may follow. In contrast with standard predictions of evolutionary rescue theory, low genetic variation may attenuate the threat of evolutionary suicide and small population sizes may facilitate escape from evolutionary traps.

  17. Testing evolutionary convergence on Europa

    International Nuclear Information System (INIS)

    Chela-Flores, Julian

    2002-11-01

    A major objective in solar system exploration is the insertion of appropriate biology-oriented experiments in future missions. We discuss various reasons for suggesting that this type of research be considered a high priority for feasibility studies and, subsequently, for technological development of appropriate melters and submersibles. Based on numerous examples, we argue in favour of the assumption that Darwin's theory is valid for the evolution of life anywhere in the universe. We have suggested how to obtain preliminary insights into the question of the distribution of life in the universe. Universal evolution of intelligent behaviour is at the end of an evolutionary pathway, in which evolution of ion channels in the membrane of microorganisms occurs in its early stages. Further, we have argued that a preliminary test of this conjecture is feasible with experiments on the Europan surface or ocean, involving evolutionary biosignatures (ion channels). This aspect of the exploration for life in the solar system should be viewed as a complement to the astronomical approach for the search of evidence of the later stages of the evolutionary pathways towards intelligent behaviour. (author)

  18. Preliminary Report Adaptive entero-omentectomy: Physiological and evolutionary bases of an auxiliary treatment to type 2 diabetes A report on the first two cases

    Directory of Open Access Journals (Sweden)

    Sérgio Santoro

    2004-09-01

    Full Text Available Objective: The objective of this article is to report on a new surgicalstrategy specifically designed to treat type 2 diabetes: adaptiveentero-omentectomy (AEO, and present its rationale andpreliminary results. Some techniques used in bariatric surgeryare capable of producing fast improvement in type 2 DiabetesMellitus, before significant loss of weight, due to metabolicchanges that are currently being explained. Methods: Two type 2diabetic patients were operated on. The technique included anenterectomy that left the first 40 cm of the jejunum and the last260 cm of the ileum, besides the resection of the greater omentum.Results: At five and seven-month follow-up, both patients had nosymptoms, reported early satiety and presented improvedmetabolic profile. Conclusions: This is the preliminary report of asurgical technique designed to help treating type 2 diabetes. It isbased on leaving the bowel in the lower limit of normal range,diminishing the highly permeable portions and taking more nutrientsto the distal bowel to enhance the secretion of enterohormones.The aim of omentectomy is to reduce visceral fat, contributing toa decreased production of plasminogen activator inhibitor-1 (PAI-1and resistin. After surgery, the patients do not need nutritionalsupport. The procedure is simple to perform and its rationale andpreliminary results are encouraging. A protocol with more patientsand long-term observation is needed.

  19. Bifurcation routes to volatility clustering under evolutionary learning

    NARCIS (Netherlands)

    Gaunersdorfer, A.; Hommes, C.H.; Wagener, F.O.O.

    2008-01-01

    A simple asset pricing model with two types of boundedly rational traders, fundamentalists and chartists, is studied. Fractions of trader types change over time according to evolutionary learning, with chartists conditioning their forecasting rule upon deviations from a benchmark fundamental.

  20. Evolutionary potential games on lattices

    Energy Technology Data Exchange (ETDEWEB)

    Szabó, György, E-mail: szabo@mfa.kfki.hu; Borsos, István, E-mail: borsos@mfa.kfki.hu

    2016-04-05

    Game theory provides a general mathematical background to study the effect of pair interactions and evolutionary rules on the macroscopic behavior of multi-player games where players with a finite number of strategies may represent a wide scale of biological objects, human individuals, or even their associations. In these systems the interactions are characterized by matrices that can be decomposed into elementary matrices (games) and classified into four types. The concept of decomposition helps the identification of potential games and also the evaluation of the potential that plays a crucial role in the determination of the preferred Nash equilibrium, and defines the Boltzmann distribution towards which these systems evolve for suitable types of dynamical rules. This survey draws parallel between the potential games and the kinetic Ising type models which are investigated for a wide scale of connectivity structures. We discuss briefly the applicability of the tools and concepts of statistical physics and thermodynamics. Additionally the general features of ordering phenomena, phase transitions and slow relaxations are outlined and applied to evolutionary games. The discussion extends to games with three or more strategies. Finally we discuss what happens when the system is weakly driven out of the “equilibrium state” by adding non-potential components representing games of cyclic dominance.

  1. Evolutionary potential games on lattices

    International Nuclear Information System (INIS)

    Szabó, György; Borsos, István

    2016-01-01

    Game theory provides a general mathematical background to study the effect of pair interactions and evolutionary rules on the macroscopic behavior of multi-player games where players with a finite number of strategies may represent a wide scale of biological objects, human individuals, or even their associations. In these systems the interactions are characterized by matrices that can be decomposed into elementary matrices (games) and classified into four types. The concept of decomposition helps the identification of potential games and also the evaluation of the potential that plays a crucial role in the determination of the preferred Nash equilibrium, and defines the Boltzmann distribution towards which these systems evolve for suitable types of dynamical rules. This survey draws parallel between the potential games and the kinetic Ising type models which are investigated for a wide scale of connectivity structures. We discuss briefly the applicability of the tools and concepts of statistical physics and thermodynamics. Additionally the general features of ordering phenomena, phase transitions and slow relaxations are outlined and applied to evolutionary games. The discussion extends to games with three or more strategies. Finally we discuss what happens when the system is weakly driven out of the “equilibrium state” by adding non-potential components representing games of cyclic dominance.

  2. Tree Contractions and Evolutionary Trees

    OpenAIRE

    Kao, Ming-Yang

    2001-01-01

    An evolutionary tree is a rooted tree where each internal vertex has at least two children and where the leaves are labeled with distinct symbols representing species. Evolutionary trees are useful for modeling the evolutionary history of species. An agreement subtree of two evolutionary trees is an evolutionary tree which is also a topological subtree of the two given trees. We give an algorithm to determine the largest possible number of leaves in any agreement subtree of two trees T_1 and ...

  3. Proteomics in evolutionary ecology.

    Science.gov (United States)

    Baer, B; Millar, A H

    2016-03-01

    Evolutionary ecologists are traditionally gene-focused, as genes propagate phenotypic traits across generations and mutations and recombination in the DNA generate genetic diversity required for evolutionary processes. As a consequence, the inheritance of changed DNA provides a molecular explanation for the functional changes associated with natural selection. A direct focus on proteins on the other hand, the actual molecular agents responsible for the expression of a phenotypic trait, receives far less interest from ecologists and evolutionary biologists. This is partially due to the central dogma of molecular biology that appears to define proteins as the 'dead-end of molecular information flow' as well as technical limitations in identifying and studying proteins and their diversity in the field and in many of the more exotic genera often favored in ecological studies. Here we provide an overview of a newly forming field of research that we refer to as 'Evolutionary Proteomics'. We point out that the origins of cellular function are related to the properties of polypeptide and RNA and their interactions with the environment, rather than DNA descent, and that the critical role of horizontal gene transfer in evolution is more about coopting new proteins to impact cellular processes than it is about modifying gene function. Furthermore, post-transcriptional and post-translational processes generate a remarkable diversity of mature proteins from a single gene, and the properties of these mature proteins can also influence inheritance through genetic and perhaps epigenetic mechanisms. The influence of post-transcriptional diversification on evolutionary processes could provide a novel mechanistic underpinning for elements of rapid, directed evolutionary changes and adaptations as observed for a variety of evolutionary processes. Modern state-of the art technologies based on mass spectrometry are now available to identify and quantify peptides, proteins, protein

  4. Paleoanthropology and evolutionary theory.

    Science.gov (United States)

    Tattersall, Ian

    2012-01-01

    Paleoanthropologists of the first half of the twentieth century were little concerned either with evolutionary theory or with the technicalities and broader implications of zoological nomenclature. In consequence, the paleoanthropological literature of the period consisted largely of a series of descriptions accompanied by authoritative pronouncements, together with a huge excess of hominid genera and species. Given the intellectual flimsiness of the resulting paleoanthropological framework, it is hardly surprising that in 1950 the ornithologist Ernst Mayr met little resistance when he urged the new postwar generation of paleoanthropologists to accept not only the elegant reductionism of the Evolutionary Synthesis but a vast oversimplification of hominid phylogenetic history and nomenclature. Indeed, the impact of Mayr's onslaught was so great that even when developments in evolutionary biology during the last quarter of the century brought other paleontologists to the realization that much more has been involved in evolutionary histories than the simple action of natural selection within gradually transforming lineages, paleoanthropologists proved highly reluctant to follow. Even today, paleoanthropologists are struggling to reconcile an intuitive realization that the burgeoning hominid fossil record harbors a substantial diversity of species (bringing hominid evolutionary patterns into line with that of other successful mammalian families), with the desire to cram a huge variety of morphologies into an unrealistically minimalist systematic framework. As long as this theoretical ambivalence persists, our perception of events in hominid phylogeny will continue to be distorted.

  5. Accurate one-centre method for hydrogen molecular ion calculation using B-spline-type basis sets in strong magnetic fields

    International Nuclear Information System (INIS)

    Zhang Yuexia; Liu Qiang; Shi Tingyun

    2012-01-01

    An accurate one-centre method is here applied to the calculation of the equilibrium distances and the energies for the hydrogen molecular ion in magnetic fields ranging from 10 9 G to 4.414 × 10 13 G. Both the radial and angular wavefunctions were expanded in terms of optimization B-splines. The slow convergence problem in the general one-centre method and singularities at the nuclear positions of the H + 2 were solved well. The accuracy of the one-centre method has been improved in this way. We compared our results with those generated by high-precision methods from published studies. Equilibrium distances of the 1σ g,u , 1π g,u , 1δ g,u and 2σ g states of the H + 2 in strong magnetic fields were found to be accurate to three to four significant digits at least up to 2.35 × 10 12 G, even for the antibonding states 1σ u , 1π g and 1δ u , whose equilibrium distances R eq are very large. (paper)

  6. Multidimensional Models of Type Ia Supernova Nebular Spectra: Strong Emission Lines from Stripped Companion Gas Rule Out Classic Single-degenerate Systems

    Science.gov (United States)

    Botyánszki, János; Kasen, Daniel; Plewa, Tomasz

    2018-01-01

    The classic single-degenerate model for the progenitors of Type Ia supernova (SN Ia) predicts that the supernova ejecta should be enriched with solar-like abundance material stripped from the companion star. Spectroscopic observations of normal SNe Ia at late times, however, have not resulted in definite detection of hydrogen. In this Letter, we study line formation in SNe Ia at nebular times using non-LTE spectral modeling. We present, for the first time, multidimensional radiative transfer calculations of SNe Ia with stripped material mixed in the ejecta core, based on hydrodynamical simulations of ejecta–companion interaction. We find that interaction models with main-sequence companions produce significant Hα emission at late times, ruling out these types of binaries being viable progenitors of SNe Ia. We also predict significant He I line emission at optical and near-infrared wavelengths for both hydrogen-rich or helium-rich material, providing an additional observational probe of stripped ejecta. We produce models with reduced stripped masses and find a more stringent mass limit of M st ≲ 1 × 10‑4 M ⊙ of stripped companion material for SN 2011fe.

  7. Eco-Evolutionary Theory and Insect Outbreaks.

    Science.gov (United States)

    Páez, David J; Dukic, Vanja; Dushoff, Jonathan; Fleming-Davies, Arietta; Dwyer, Greg

    2017-06-01

    Eco-evolutionary theory argues that population cycles in consumer-resource interactions are partly driven by natural selection, such that changes in densities and changes in trait values are mutually reinforcing. Evidence that the theory explains cycles in nature, however, is almost nonexistent. Experimental tests of model assumptions are logistically impractical for most organisms, while for others, evidence that population cycles occur in nature is lacking. For insect baculoviruses in contrast, tests of model assumptions are straightforward, and there is strong evidence that baculoviruses help drive population cycles in many insects, including the gypsy moth that we study here. We therefore used field experiments with the gypsy moth baculovirus to test two key assumptions of eco-evolutionary models of host-pathogen population cycles: that reduced host infection risk is heritable and that it is costly. Our experiments confirm both assumptions, and inserting parameters estimated from our data into eco-evolutionary insect-outbreak models gives cycles closely resembling gypsy moth outbreak cycles in North America, whereas standard models predict unrealistic stable equilibria. Our work shows that eco-evolutionary models are useful for explaining outbreaks of forest insect defoliators, while widespread observations of intense selection on defoliators in nature and of heritable and costly resistance in defoliators in the lab together suggest that eco-evolutionary dynamics may play a general role in defoliator outbreaks.

  8. Evolutionary Statistical Procedures

    CERN Document Server

    Baragona, Roberto; Poli, Irene

    2011-01-01

    This proposed text appears to be a good introduction to evolutionary computation for use in applied statistics research. The authors draw from a vast base of knowledge about the current literature in both the design of evolutionary algorithms and statistical techniques. Modern statistical research is on the threshold of solving increasingly complex problems in high dimensions, and the generalization of its methodology to parameters whose estimators do not follow mathematically simple distributions is underway. Many of these challenges involve optimizing functions for which analytic solutions a

  9. A study of ion exchange equilibrium for some uni-univalent and uni-divalent reaction systems using strongly basic anion exchange resin Indion-830 (Type 1)

    Science.gov (United States)

    Lokhande, R. S.; Singare, P. U.; Patil, A. B.

    2007-12-01

    A study of the thermodynamics of ion exchange equilibrium for uni-univalent Cl-/I-, Cl-/Br- and uni-divalent Cl-/SO{4/2-}, Cl-/C2O{4/2-} reaction systems was carried out using ion exchange resin Indion-830 (Type 1). The equilibrium constant K was calculated by taking into account the activity coefficients of ions both in solution and in the resin phase. For uni-univalent ion exchange reaction systems, the equilibrium constants K' were also calculated from the mole fraction of ions in the resin phase. The K values calculated for uni-univalent and uni-divalent anion exchange reaction systems increased as the temperature grew, indicating the endothermic character of the exchange reactions with enthalpies of 38.2, 32.3, 7.6, and 11.4 kJ/mol, respectively.

  10. Analyzing Evolutionary Optimization in Noisy Environments.

    Science.gov (United States)

    Qian, Chao; Yu, Yang; Zhou, Zhi-Hua

    2018-01-01

    Many optimization tasks must be handled in noisy environments, where the exact evaluation of a solution cannot be obtained, only a noisy one. For optimization of noisy tasks, evolutionary algorithms (EAs), a type of stochastic metaheuristic search algorithm, have been widely and successfully applied. Previous work mainly focuses on the empirical study and design of EAs for optimization under noisy conditions, while the theoretical understandings are largely insufficient. In this study, we first investigate how noisy fitness can affect the running time of EAs. Two kinds of noise-helpful problems are identified, on which the EAs will run faster with the presence of noise, and thus the noise should not be handled. Second, on a representative noise-harmful problem in which the noise has a strong negative effect, we examine two commonly employed mechanisms dealing with noise in EAs: reevaluation and threshold selection. The analysis discloses that using these two strategies simultaneously is effective for the one-bit noise but ineffective for the asymmetric one-bit noise. Smooth threshold selection is then proposed, which can be proved to be an effective strategy to further improve the noise tolerance ability in the problem. We then complement the theoretical analysis by experiments on both synthetic problems as well as two combinatorial problems, the minimum spanning tree and the maximum matching. The experimental results agree with the theoretical findings and also show that the proposed smooth threshold selection can deal with the noise better.

  11. Nephrotic range proteinuria as a strong risk factor for rapid renal function decline during pre-dialysis phase in type 2 diabetic patients with severely impaired renal function.

    Science.gov (United States)

    Kitai, Yuichiro; Doi, Yohei; Osaki, Keisuke; Sugioka, Sayaka; Koshikawa, Masao; Sugawara, Akira

    2015-12-01

    Proteinuria is an established risk factor for progression of renal disease, including diabetic nephropathy. The predictive power of proteinuria, especially nephrotic range proteinuria, for progressive renal deterioration has been well demonstrated in diabetic patients with normal to relatively preserved renal function. However, little is known about the relationship between severity of proteinuria and renal outcome in pre-dialysis diabetic patients with severely impaired renal function. 125 incident dialysis patients with type 2 diabetes were identified. This study was aimed at retrospectively evaluating the impact of nephrotic range proteinuria (urinary protein-creatinine ratio above 3.5 g/gCr) on renal function decline during the 3 months just prior to dialysis initiation. In total, 103 patients (82.4 %) had nephrotic range proteinuria. The median rate of decline in estimated glomerular filtration rate (eGFR) in this study population was 0.98 (interquartile range 0.51-1.46) ml/min/1.73 m(2) per month. Compared to patients without nephrotic range proteinuria, patients with nephrotic range proteinuria showed significantly faster renal function decline (0.46 [0.24-1.25] versus 1.07 [0.64-1.54] ml/min/1.73 m(2) per month; p = 0.007). After adjusting for gender, age, systolic blood pressure, serum albumin, calcium-phosphorus product, hemoglobin A1c, and use of an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, patients with nephrotic range proteinuria showed a 3.89-fold (95 % CI 1.08-14.5) increased risk for rapid renal function decline defined as a decline in eGFR ≥0.5 ml/min/1.73 m(2) per month. Nephrotic range proteinuria is the predominant renal risk factor in type 2 diabetic patients with severely impaired renal function receiving pre-dialysis care.

  12. Evolutionary stability in the asymmetric volunteer's dilemma.

    Directory of Open Access Journals (Sweden)

    Jun-Zhou He

    Full Text Available It is often assumed that in public goods games, contributors are either strong or weak players and each individual has an equal probability of exhibiting cooperation. It is difficult to explain why the public good is produced by strong individuals in some cooperation systems, and by weak individuals in others. Viewing the asymmetric volunteer's dilemma game as an evolutionary game, we find that whether the strong or the weak players produce the public good depends on the initial condition (i.e., phenotype or initial strategy of individuals. These different evolutionarily stable strategies (ESS associated with different initial conditions, can be interpreted as the production modes of public goods of different cooperation systems. A further analysis revealed that the strong player adopts a pure strategy but mixed strategies for the weak players to produce the public good, and that the probability of volunteering by weak players decreases with increasing group size or decreasing cost-benefit ratio. Our model shows that the defection probability of a "strong" player is greater than the "weak" players in the model of Diekmann (1993. This contradicts Selten's (1980 model that public goods can only be produced by a strong player, is not an evolutionarily stable strategy, and will therefore disappear over evolutionary time. Our public good model with ESS has thus extended previous interpretations that the public good can only be produced by strong players in an asymmetric game.

  13. The essence of Schumpeter's evolutionary economics

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    Schumpeter’s unique type of evolutionary analysis can hardly be understood unless we recognise that he developed it in relation to a study of the strength and weaknesses of the Walrasian form of neoclassical economics. The paper demonstrates that Schumpeter’s major steps were already performed...

  14. Molluscan Evolutionary Development

    DEFF Research Database (Denmark)

    Wanninger, Andreas Wilhelm Georg; Koop, Damien; Moshel-Lynch, Sharon

    2008-01-01

    Brought together by Winston F. Ponder and David R. Lindberg, thirty-six experts on the evolution of the Mollusca provide an up-to-date review of its evolutionary history. The Mollusca are the second largest animal phylum and boast a fossil record of over 540 million years. They exhibit remarkable...

  15. Origins of evolutionary transitions

    Indian Academy of Sciences (India)

    An `evolutionary transition in individuality' or `major transition' is a transformation in the hierarchical level at which natural selection operates on a population. In this article I give an abstract (i.e. level-neutral and substrate-neutral) articulation of the transition process in order to precisely understand how such processes can ...

  16. Origins of evolutionary transitions

    Indian Academy of Sciences (India)

    2014-03-15

    Mar 15, 2014 ... collectivist life forms have spread through the population, the situation – the terms of the evolutionary game – have changed. Where initially there ...... Kerr B and Godfrey-Smith P 2002 Individualist and multi-level perspectives on selection in structured populations. Biol. Philos. 17 477–517. Kirk DL 1998 ...

  17. Evolutionary Stable Strategy

    Indian Academy of Sciences (India)

    IAS Admin

    After Maynard-Smith and Price [1] mathematically derived why a given behaviour or strategy was adopted by a certain proportion of the population at a given time, it was shown that a strategy which is currently stable in a population need not be stable in evolutionary time (across generations). Additionally it was sug-.

  18. Editorial overview: Evolutionary psychology

    NARCIS (Netherlands)

    Gangestad, S.W.; Tybur, J.M.

    2016-01-01

    Functional approaches in psychology - which ask what behavior is good for - are almost as old as scientific psychology itself. Yet sophisticated, generative functional theories were not possible until developments in evolutionary biology in the mid-20th century. Arising in the last three decades,

  19. Evolutionary trends in Heteroptera

    NARCIS (Netherlands)

    Cobben, R.H.

    1968-01-01

    1. This work, the first volume of a series dealing with evolutionary trends in Heteroptera, is concerned with the egg system of about 400 species. The data are presented systematically in chapters 1 and 2 with a critical review of the literature after each family.

    2. Chapter 3 evaluates facts

  20. Interfaces in evolutionary games

    Science.gov (United States)

    Kolotev, Sergei; Malyutin, Aleksandr; Burovski, Evgeni; Shchur, Lev

    2018-01-01

    We investigate geometrical aspects of a spatial evolutionary game. The game is based on the Prisoner’s dilemma. We analyze the geometrical structure of the space distribution of cooperators and defectors in the steady-state regime of evolution. We develop algorithm for the identification of the interfaces between clusters of cooperators and defectors, and measure fractal properties of the interfaces.

  1. Origins of evolutionary transitions

    Indian Academy of Sciences (India)

    2014-03-15

    Mar 15, 2014 ... was to define a major transition by identifying a pattern that is common across an otherwise diverse set of ... been many major evolutionary events that this definition of a transition excludes. The evolution of ...... fragmentation periodic, or brings it under endogenous con- trol. So the mechanisms are far from ...

  2. Evolutionary perspectives on ageing.

    Science.gov (United States)

    Reichard, Martin

    2017-10-01

    From an evolutionary perspective, ageing is a decrease in fitness with chronological age - expressed by an increase in mortality risk and/or decline in reproductive success and mediated by deterioration of functional performance. While this makes ageing intuitively paradoxical - detrimental to individual fitness - evolutionary theory offers answers as to why ageing has evolved. In this review, I first briefly examine the classic evolutionary theories of ageing and their empirical tests, and highlight recent findings that have advanced our understanding of the evolution of ageing (condition-dependent survival, positive pleiotropy). I then provide an overview of recent theoretical extensions and modifications that accommodate those new discoveries. I discuss the role of indeterminate (asymptotic) growth for lifetime increases in fecundity and ageing trajectories. I outline alternative views that challenge a universal existence of senescence - namely the lack of a germ-soma distinction and the ability of tissue replacement and retrogression to younger developmental stages in modular organisms. I argue that rejuvenation at the organismal level is plausible, but includes a return to a simple developmental stage. This may exempt a particular genotype from somatic defects but, correspondingly, removes any information acquired during development. A resolution of the question of whether a rejuvenated individual is the same entity is central to the recognition of whether current evolutionary theories of ageing, with their extensions and modifications, can explain the patterns of ageing across the Tree of Life. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Evolutionary Developmental Psychology.

    Science.gov (United States)

    Geary, David C.; Bjorklund, David F.

    2000-01-01

    Describes evolutionary developmental psychology as the study of the genetic and ecological mechanisms that govern the development of social and cognitive competencies common to all human beings and the epigenetic (gene-environment interactions) processes that adapt these competencies to local conditions. Outlines basic assumptions and domains of…

  4. Applications of Evolutionary Computation

    NARCIS (Netherlands)

    Mora, Antonio M.; Squillero, Giovanni; Di Chio, C; Agapitos, Alexandros; Cagnoni, Stefano; Cotta, Carlos; Fernández De Vega, F; Di Caro, G A; Drechsler, R.; Ekárt, A; Esparcia-Alcázar, Anna I.; Farooq, M; Langdon, W B; Merelo-Guervós, J.J.; Preuss, M; Richter, O.-M.H.; Silva, Sara; Sim$\\$~oes, A; Squillero, Giovanni; Tarantino, Ernesto; Tettamanzi, Andrea G B; Togelius, J; Urquhart, Neil; Uyar, A S; Yannakakis, G N; Smith, Stephen L; Caserta, Marco; Ramirez, Adriana; Voß, Stefan; Squillero, Giovanni; Burelli, Paolo; Mora, Antonio M.; Squillero, Giovanni; Jan, Mathieu; Matthias, M; Di Chio, C; Agapitos, Alexandros; Cagnoni, Stefano; Cotta, Carlos; Fernández De Vega, F; Di Caro, G A; Drechsler, R.; Ekárt, A; Esparcia-Alcázar, Anna I.; Farooq, M; Langdon, W B; Merelo-Guervós, J.J.; Preuss, M; Richter, O.-M.H.; Silva, Sara; Sim$\\$~oes, A; Squillero, Giovanni; Tarantino, Ernesto; Tettamanzi, Andrea G B; Togelius, J; Urquhart, Neil; Uyar, A S; Yannakakis, G N; Caserta, Marco; Ramirez, Adriana; Voß, Stefan; Squillero, Giovanni; Burelli, Paolo; Esparcia-Alcazar, Anna I; Silva, Sara; Agapitos, Alexandros; Cotta, Carlos; De Falco, Ivanoe; Cioppa, Antonio Della; Diwold, Konrad; Ekart, Aniko; Tarantino, Ernesto; Vega, Francisco Fernandez De; Burelli, Paolo; Sim, Kevin; Cagnoni, Stefano; Simoes, Anabela; Merelo, J.J.; Urquhart, Neil; Haasdijk, Evert; Zhang, Mengjie; Squillero, Giovanni; Eiben, A E; Tettamanzi, Andrea G B; Glette, Kyrre; Rohlfshagen, Philipp; Schaefer, Robert; Caserta, Marco; Ramirez, Adriana; Voß, Stefan

    2015-01-01

    The application of genetic and evolutionary computation to problems in medicine has increased rapidly over the past five years, but there are specific issues and challenges that distinguish it from other real-world applications. Obtaining reliable and coherent patient data, establishing the clinical

  5. A Mouse Monoclonal Antibody against Dengue Virus Type 1 Mochizuki Strain Targeting Envelope Protein Domain II and Displaying Strongly Neutralizing but Not Enhancing Activity

    Science.gov (United States)

    Kotaki, Tomohiro; Konishi, Eiji

    2013-01-01

    Dengue fever and its more severe form, dengue hemorrhagic fever, are major global concerns. Infection-enhancing antibodies are major factors hypothetically contributing to increased disease severity. In this study, we generated 26 monoclonal antibodies (MAbs) against the dengue virus type 1 Mochizuki strain. We selected this strain because a relatively large number of unique and rare amino acids were found on its envelope protein. Although most MAbs showing neutralizing activities exhibited enhancing activities at subneutralizing doses, one MAb (D1-IV-7F4 [7F4]) displayed neutralizing activities without showing enhancing activities at lower concentrations. In contrast, another MAb (D1-V-3H12 [3H12]) exhibited only enhancing activities, which were suppressed by pretreatment of cells with anti-FcγRIIa. Although antibody engineering revealed that antibody subclass significantly affected 7F4 (IgG3) and 3H12 (IgG1) activities, neutralizing/enhancing activities were also dependent on the epitope targeted by the antibody. 7F4 recognized an epitope on the envelope protein containing E118 (domain II) and had a neutralizing activity 10- to 1,000-fold stronger than the neutralizing activity of previously reported human or humanized neutralizing MAbs targeting domain I and/or domain II. An epitope-blocking enzyme-linked immunosorbent assay (ELISA) indicated that a dengue virus-immune population possessed antibodies sharing an epitope with 7F4. Our results demonstrating induction of these antibody species (7F4 and 3H12) in Mochizuki-immunized mice may have implications for dengue vaccine strategies designed to minimize induction of enhancing antibodies in vaccinated humans. PMID:24049185

  6. Arabidopsis type I proton-pumping pyrophosphatase expresses strongly in phloem, where it is required for pyrophosphate metabolism and photosynthate partitioning.

    Science.gov (United States)

    Pizzio, Gaston A; Paez-Valencia, Julio; Khadilkar, Aswad S; Regmi, Kamesh; Patron-Soberano, Araceli; Zhang, Shangji; Sanchez-Lares, Jonathan; Furstenau, Tara; Li, Jisheng; Sanchez-Gomez, Concepcion; Valencia-Mayoral, Pedro; Yadav, Umesh P; Ayre, Brian G; Gaxiola, Roberto A

    2015-04-01

    Phloem loading is a critical process in plant physiology. The potential of regulating the translocation of photoassimilates from source to sink tissues represents an opportunity to increase crop yield. Pyrophosphate homeostasis is crucial for normal phloem function in apoplasmic loaders. The involvement of Arabidopsis (Arabidopsis thaliana) type I proton-pumping pyrophosphatase (AVP1) in phloem loading was analyzed at genetic, histochemical, and physiological levels. A transcriptional AVP1 promoter::GUS fusion revealed phloem activity in source leaves. Ubiquitous AVP1 overexpression (35S::AVP1 cassette) enhanced shoot biomass, photoassimilate production and transport, rhizosphere acidification, and expression of sugar-induced root ion transporter genes (POTASSIUM TRANSPORTER2 [KUP2], NITRATE TRANSPORTER2.1 [NRT2.1], NRT2.4, and PHOSPHATE TRANSPORTER1.4 [PHT1.4]). Phloem-specific AVP1 overexpression (Commelina Yellow Mottle Virus promoter [pCOYMV]::AVP1) elicited similar phenotypes. By contrast, phloem-specific AVP1 knockdown (pCoYMV::RNAiAVP1) resulted in stunted seedlings in sucrose-deprived medium. We also present a promoter mutant avp1-2 (SALK046492) with a 70% reduction of expression that did not show severe growth impairment. Interestingly, AVP1 protein in this mutant is prominent in the phloem. Moreover, expression of an Escherichia coli-soluble pyrophosphatase in the phloem (pCoYMV::pyrophosphatase) of avp1-2 plants resulted in severe dwarf phenotype and abnormal leaf morphology. We conclude that the Proton-Pumping Pyrophosphatase AVP1 localized at the plasma membrane of the sieve element-companion cell complexes functions as a synthase, and that this activity is critical for the maintenance of pyrophosphate homeostasis required for phloem function. © 2015 American Society of Plant Biologists. All Rights Reserved.

  7. Evolutionary thinking: "A conversation with Carter Phipps about the role of evolutionary thinking in modern culture".

    Science.gov (United States)

    Hunt, Tam

    2014-12-01

    Evolution as an idea has a lengthy history, even though the idea of evolution is generally associated with Darwin today. Rebecca Stott provides an engaging and thoughtful overview of this history of evolutionary thinking in her 2013 book, Darwin's Ghosts: The Secret History of Evolution. Since Darwin, the debate over evolution-both how it takes place and, in a long war of words with religiously-oriented thinkers, whether it takes place-has been sustained and heated. A growing share of this debate is now devoted to examining how evolutionary thinking affects areas outside of biology. How do our lives change when we recognize that all is in flux? What can we learn about life more generally if we study change instead of stasis? Carter Phipps' book, Evolutionaries: Unlocking the Spiritual and Cultural Potential of Science's Greatest Idea, delves deep into this relatively new development. Phipps generally takes as a given the validity of the Modern Synthesis of evolutionary biology. His story takes us into, as the subtitle suggests, the spiritual and cultural implications of evolutionary thinking. Can religion and evolution be reconciled? Can evolutionary thinking lead to a new type of spirituality? Is our culture already being changed in ways that we don't realize by evolutionary thinking? These are all important questions and Phipps book is a great introduction to this discussion. Phipps is an author, journalist, and contributor to the emerging "integral" or "evolutionary" cultural movement that combines the insights of Integral Philosophy, evolutionary science, developmental psychology, and the social sciences. He has served as the Executive Editor of EnlightenNext magazine (no longer published) and more recently is the co-founder of the Institute for Cultural Evolution, a public policy think tank addressing the cultural roots of America's political challenges. What follows is an email interview with Phipps.

  8. PsasM2I, a type II restriction-modification system in Pseudomonas savastanoi pv. savastanoi: differential distribution of carrier strains in the environment and the evolutionary history of homologous RM systems in the Pseudomonas syringae complex.

    Science.gov (United States)

    Cinelli, Tamara; Moscetti, Ilaria; Marchi, Guido

    2014-11-01

    A type II restriction-modification system was found in a native plasmid of Pseudomonas savastanoi pv. savastanoi MLLI2. Functional analysis of the methyltransferase showed that the enzyme acts by protecting the DNA sequence CTGCAG from cleavage. Restriction endonuclease expression in recombinant Escherichia coli cells resulted in mutations in the REase sequence or transposition of insertion sequence 1A in the coding sequence, preventing lethal gene expression. Population screening detected homologous RM systems in other P. savastanoi strains and in the Pseudomonas syringae complex. An epidemiological survey carried out by sampling olive and oleander knots in two Italian regions showed an uneven diffusion of carrier strains, whose presence could be related to a selective advantage in maintaining the RM system in particular environments or subpopulations. Moreover, carrier strains can coexist in the same orchards, plants, and knot tissues with non-carriers, revealing unexpected genetic variability on a very small spatial scale. Phylogenetic analysis of the RM system and housekeeping gene sequences in the P. syringae complex demonstrated the ancient acquisition of the RM systems. However, the evolutionary history of the gene complex also showed the involvement of horizontal gene transfer between related strains and recombination events.

  9. Adaptive evolutionary artificial neural networks for pattern classification.

    Science.gov (United States)

    Oong, Tatt Hee; Isa, Nor Ashidi Mat

    2011-11-01

    This paper presents a new evolutionary approach called the hybrid evolutionary artificial neural network (HEANN) for simultaneously evolving an artificial neural networks (ANNs) topology and weights. Evolutionary algorithms (EAs) with strong global search capabilities are likely to provide the most promising region. However, they are less efficient in fine-tuning the search space locally. HEANN emphasizes the balancing of the global search and local search for the evolutionary process by adapting the mutation probability and the step size of the weight perturbation. This is distinguishable from most previous studies that incorporate EA to search for network topology and gradient learning for weight updating. Four benchmark functions were used to test the evolutionary framework of HEANN. In addition, HEANN was tested on seven classification benchmark problems from the UCI machine learning repository. Experimental results show the superior performance of HEANN in fine-tuning the network complexity within a small number of generations while preserving the generalization capability compared with other algorithms.

  10. A teleofunctional account of evolutionary mismatch.

    Science.gov (United States)

    Cofnas, Nathan

    When the environment in which an organism lives deviates in some essential way from that to which it is adapted, this is described as "evolutionary mismatch," or "evolutionary novelty." The notion of mismatch plays an important role, explicitly or implicitly, in evolution-informed cognitive psychology, clinical psychology, and medicine. The evolutionary novelty of our contemporary environment is thought to have significant implications for our health and well-being. However, scientists have generally been working without a clear definition of mismatch. This paper defines mismatch as deviations in the environment that render biological traits unable, or impaired in their ability, to produce their selected effects (i.e., to perform their proper functions in Neander's sense). The machinery developed by Millikan in connection with her account of proper function, and with her related teleosemantic account of representation, is used to identify four major types, and several subtypes, of evolutionary mismatch. While the taxonomy offered here does not in itself resolve any scientific debates, the hope is that it can be used to better formulate empirical hypotheses concerning the effects of mismatch. To illustrate, it is used to show that the controversial hypothesis that general intelligence evolved as an adaptation to handle evolutionary novelty can, contra some critics, be formulated in a conceptually coherent way.

  11. Evolutionary genetics: the Drosophila model

    Indian Academy of Sciences (India)

    Unknown

    In Evolutionary genetics: from molecules to morphology (ed. R. S. Singh and C. B. Krimbas), pp. 609–627. Cambridge Uni- versity Press, Cambridge. Houle D. 2001 Characters as the units of evolutionary change. In The character concept in evolutionary biology. (ed. G. P. Wagner), pp. 109–140. Academic Press, San Diego.

  12. Experimental evolution reveals hidden diversity in evolutionary pathways.

    Science.gov (United States)

    Lind, Peter A; Farr, Andrew D; Rainey, Paul B

    2015-03-25

    Replicate populations of natural and experimental organisms often show evidence of parallel genetic evolution, but the causes are unclear. The wrinkly spreader morph of Pseudomonas fluorescens arises repeatedly during experimental evolution. The mutational causes reside exclusively within three pathways. By eliminating these, 13 new mutational pathways were discovered with the newly arising WS types having fitnesses similar to those arising from the commonly passaged routes. Our findings show that parallel genetic evolution is strongly biased by constraints and we reveal the genetic bases. From such knowledge, and in instances where new phenotypes arise via gene activation, we suggest a set of principles: evolution proceeds firstly via pathways subject to negative regulation, then via promoter mutations and gene fusions, and finally via activation by intragenic gain-of-function mutations. These principles inform evolutionary forecasting and have relevance to interpreting the diverse array of mutations associated with clinically identical instances of disease in humans.

  13. Evolutionary constrained optimization

    CERN Document Server

    Deb, Kalyanmoy

    2015-01-01

    This book makes available a self-contained collection of modern research addressing the general constrained optimization problems using evolutionary algorithms. Broadly the topics covered include constraint handling for single and multi-objective optimizations; penalty function based methodology; multi-objective based methodology; new constraint handling mechanism; hybrid methodology; scaling issues in constrained optimization; design of scalable test problems; parameter adaptation in constrained optimization; handling of integer, discrete and mix variables in addition to continuous variables; application of constraint handling techniques to real-world problems; and constrained optimization in dynamic environment. There is also a separate chapter on hybrid optimization, which is gaining lots of popularity nowadays due to its capability of bridging the gap between evolutionary and classical optimization. The material in the book is useful to researchers, novice, and experts alike. The book will also be useful...

  14. Anxiety: an evolutionary approach.

    OpenAIRE

    Bateson, M; Brilot, B; Nettle, D

    2011-01-01

    Anxiety disorders are among the most common mental illnesses, with huge attendant suffering. Current treatments are not universally effective, suggesting that a deeper understanding of the causes of anxiety is needed. To understand anxiety disorders better, it is first necessary to understand the normal anxiety response. This entails considering its evolutionary function as well as the mechanisms underlying it. We argue that the function of the human anxiety response, and homologues in other ...

  15. Evolutionary Dynamics of Globalization

    OpenAIRE

    Naci Canpolat; Hüseyin Ozel

    2008-01-01

    The expansion of markets –globalization– was reversed during early 20th century and unfettered markets gave in to the welfare state and central planning. But the markets have been striking back since the early 1980s. Governments are withdrawn from economic activities, and many structural market reforms are implemented. Now the question is: Can the forces that market expansion create again reverse this expansion? This paper seeks an answer to this question by constructing an evolutionary game ...

  16. Asymmetric Evolutionary Games.

    Science.gov (United States)

    McAvoy, Alex; Hauert, Christoph

    2015-08-01

    Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner's Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games.

  17. Asymmetric Evolutionary Games.

    Directory of Open Access Journals (Sweden)

    Alex McAvoy

    2015-08-01

    Full Text Available Evolutionary game theory is a powerful framework for studying evolution in populations of interacting individuals. A common assumption in evolutionary game theory is that interactions are symmetric, which means that the players are distinguished by only their strategies. In nature, however, the microscopic interactions between players are nearly always asymmetric due to environmental effects, differing baseline characteristics, and other possible sources of heterogeneity. To model these phenomena, we introduce into evolutionary game theory two broad classes of asymmetric interactions: ecological and genotypic. Ecological asymmetry results from variation in the environments of the players, while genotypic asymmetry is a consequence of the players having differing baseline genotypes. We develop a theory of these forms of asymmetry for games in structured populations and use the classical social dilemmas, the Prisoner's Dilemma and the Snowdrift Game, for illustrations. Interestingly, asymmetric games reveal essential differences between models of genetic evolution based on reproduction and models of cultural evolution based on imitation that are not apparent in symmetric games.

  18. Notes on an evolutionary medicine.

    Science.gov (United States)

    Weiner, H

    1998-01-01

    Medicine does not have a comprehensive theory of health, ill-health, and disease. Its explanations of disease are firmly rooted in pathological anatomy brought about by infection, intoxication, trauma, and mutations in genes. Because medical concepts have been influenced mainly by classical physics, it is mechanistic, materialistic, deterministic, reductionistic, linear-causal, and strongly biased toward proximate explanations of disease. Of late, many thoughtful persons have attempted to provide medicine with a more comprehensive theory that integrates the documented roles of physical, social, environmental, and psychological factors in the etiology and pathogenesis of ill-health and disease (eg, Refs. 1-3). Until very recently (4), no one has clearly pointed out that such a comprehensive theory should be guided by the concepts of evolutionary and organismic biology. Darwin's great theory states that evolution is "driven," but not exclusively so, by natural and sexual selection. Natural selection acts on variants that differ in adaptive capacities. Those capable of adaptation survive to reproduce. Failure to adapt reduces reproductive fitness and success, and leads to injury or death. But this formulation could be expanded to regard ill-health and disease as adaptive failures, whereas health usually may be conceived of as equivalent to adaptive success. Adaptations are determined by many factors-genetic, morphological, physiological, and behavioral. Selective pressures are many and varied. However, social primates are at a selective advantage, and are among the most successful species and varieties. Social behavior (eg, support) seems to enhance the chances of survival and reproductive fitness. Physiological (immunological, metabolic, cardiovascular) and behavioral adaptations are geared specifically for interactions with the environment. Emotions have evolved as ways of matching physiological responses with environmental demands and signaling the organism's state

  19. Misrepresentations of evolutionary psychology in sex and gender textbooks.

    Science.gov (United States)

    Winegard, Benjamin M; Winegard, Bo M; Deaner, Robert O

    2014-05-20

    Evolutionary psychology has provoked controversy, especially when applied to human sex differences. We hypothesize that this is partly due to misunderstandings of evolutionary psychology that are perpetuated by undergraduate sex and gender textbooks. As an initial test of this hypothesis, we develop a catalog of eight types of errors and document their occurrence in 15 widely used sex and gender textbooks. Consistent with our hypothesis, of the 12 textbooks that discussed evolutionary psychology, all contained at least one error, and the median number of errors was five. The most common types of errors were "Straw Man," "Biological Determinism," and "Species Selection." We conclude by suggesting improvements to undergraduate sex and gender textbooks.

  20. Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management.

    Science.gov (United States)

    Laugen, Ane T; Engelhard, Georg H; Whitlock, Rebecca; Arlinghaus, Robert; Dankel, Dorothy J; Dunlop, Erin S; Eikeset, Anne M; Enberg, Katja; Jørgensen, Christian; Matsumura, Shuichi; Nusslé, Sébastien; Urbach, Davnah; Baulier, Loїc; Boukal, David S; Ernande, Bruno; Johnston, Fiona D; Mollet, Fabian; Pardoe, Heidi; Therkildsen, Nina O; Uusi-Heikkilä, Silva; Vainikka, Anssi; Heino, Mikko; Rijnsdorp, Adriaan D; Dieckmann, Ulf

    2014-03-01

    Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries-induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life-history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. EvoIA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries.

  1. Replicated evolutionary divergence in the cuticular hydrocarbon profile of male crickets associated with the loss of song in the Hawaiian archipelago.

    Science.gov (United States)

    Simmons, L W; Thomas, M L; Gray, B; Zuk, M

    2014-10-01

    Female choice based on male secondary sexual traits is well documented, although the extent to which this selection can drive an evolutionary divergence in male traits among populations is less clear. Male field crickets Teleogryllus oceanicus attract females using a calling song and once contacted switch to courtship song to persuade them to mate. These crickets also secrete onto their cuticle a cocktail of long-chained fatty acids or cuticular hydrocarbons (CHCs). Females choose among potential mates based on the structure of male acoustic signals and on the composition of male CHC profiles. Here, we utilize two naturally occurring mutations that have arisen independently on two Hawaiian islands and render the male silent to ask whether the evolutionary loss of acoustic signalling can drive an evolutionary divergence in the alternative signalling modality, male CHC profiles. QST -FST comparisons revealed strong patterns of CHC divergence among three populations of crickets on the islands of Hawaii, Oahu and Kauai. Contrasts between wild-type and flatwing males on the islands of Oahu and Kauai indicated that variation in male CHC profiles within populations is associated with the loss of acoustic signalling; flatwing males had a relatively low abundance of long-chained CHCs relative to the short-chained CHCs that females find attractive. Given their dual functions in desiccation resistance and sexual signalling, insect CHCs may be particularly important traits for reproductive isolation and ultimately speciation. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  2. Testing strong interaction theories

    International Nuclear Information System (INIS)

    Ellis, J.

    1979-01-01

    The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)

  3. Evolutionary patterns and processes

    DEFF Research Database (Denmark)

    Leonardi, Michela; Sanz, Pablo Librado; Der Sarkissian, Clio

    2017-01-01

    Ever since its emergence in 1984, the field of ancient DNA has struggled to overcome the challenges related to the decay of DNA molecules in the fossil record. With the recent development of high-throughput DNA sequencing technologies and molecular techniques tailored to ultra-damaged templates......, it has now come of age, merging together approaches in phylogenomics, population genomics, epigenomics, and metagenomics. Leveraging on complete temporal sample series, ancient DNA provides direct access to the most important dimension in evolution-time, allowing a wealth of fundamental evolutionary...

  4. Molluscan Evolutionary Development

    DEFF Research Database (Denmark)

    Wanninger, Andreas Wilhelm Georg; Koop, Damien; Moshel-Lynch, Sharon

    2008-01-01

    Brought together by Winston F. Ponder and David R. Lindberg, thirty-six experts on the evolution of the Mollusca provide an up-to-date review of its evolutionary history. The Mollusca are the second largest animal phylum and boast a fossil record of over 540 million years. They exhibit remarkable...... anatomical diversity and include the bivalves (scallops, oysters, and clams), gastropods (limpets, snails, and slugs), and cephalopods (squid, cuttlefish, and octopus). This study treats each major taxon and supplies general information as well as overviews of evolution and phylogeny using data from...... different sources--morphological, ultrastructural, molecular, developmental, and from the fossil record....

  5. Evolutionary phenomena in galaxies

    International Nuclear Information System (INIS)

    Beckman, J.E.; Pagel, B.E.J.

    1989-01-01

    This book reviews the subject of evolutionary phenomena in galaxies, bringing together contributions by experts on all the relevant physics and astrophysics necessary to understand galaxies and how they work. The book is based on the proceedings of a conference held in July 1988 in Puerto de la Cruz, Tenerife which was timed to coincide with the first year of operation of the 4.2 m William Herschel Telescope. The broad topics covered include formation of galaxies and their ages, stellar dynamics, galactic scale gas and its role in star formation and the production and distribution of the chemical elements within galaxies. (author)

  6. Evolutionary genomics of Entamoeba

    Science.gov (United States)

    Weedall, Gareth D.; Hall, Neil

    2011-01-01

    Entamoeba histolytica is a human pathogen that causes amoebic dysentery and leads to significant morbidity and mortality worldwide. Understanding the genome and evolution of the parasite will help explain how, when and why it causes disease. Here we review current knowledge about the evolutionary genomics of Entamoeba: how differences between the genomes of different species may help explain different phenotypes, and how variation among E. histolytica parasites reveals patterns of population structure. The imminent expansion of the amount genome data will greatly improve our knowledge of the genus and of pathogenic species within it. PMID:21288488

  7. The SNAP Strong Lens Survey

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, P.

    2005-01-03

    Basic considerations of lens detection and identification indicate that a wide field survey of the types planned for weak lensing and Type Ia SNe with SNAP are close to optimal for the optical detection of strong lenses. Such a ''piggy-back'' survey might be expected even pessimistically to provide a catalogue of a few thousand new strong lenses, with the numbers dominated by systems of faint blue galaxies lensed by foreground ellipticals. After sketching out our strategy for detecting and measuring these galaxy lenses using the SNAP images, we discuss some of the scientific applications of such a large sample of gravitational lenses: in particular we comment on the partition of information between lens structure, the source population properties and cosmology. Understanding this partitioning is key to assessing strong lens cosmography's value as a cosmological probe.

  8. Practical advantages of evolutionary computation

    Science.gov (United States)

    Fogel, David B.

    1997-10-01

    Evolutionary computation is becoming a common technique for solving difficult, real-world problems in industry, medicine, and defense. This paper reviews some of the practical advantages to using evolutionary algorithms as compared with classic methods of optimization or artificial intelligence. Specific advantages include the flexibility of the procedures, as well as their ability to self-adapt the search for optimum solutions on the fly. As desktop computers increase in speed, the application of evolutionary algorithms will become routine.

  9. Evolutionary explanations for natural language: criteria from evolutionary biology

    NARCIS (Netherlands)

    Zuidema, W.; de Boer, B.

    2008-01-01

    Theories of the evolutionary origins of language must be informed by empirical and theoretical results from a variety of different fields. Complementing recent surveys of relevant work from linguistics, animal behaviour and genetics, this paper surveys the requirements on evolutionary scenarios that

  10. Phylogeny of an Albugo sp. infecting Barbarea vulgaris in Denmark and its frequency of symptom development in natural populations of two evolutionary divergent plant types

    DEFF Research Database (Denmark)

    van Mölken, Tamara; Heimes, Christine; Hauser, Thure Pavlo

    2014-01-01

    The oomycete Albugo candida has long been considered a broad spectrum generalist pathogen, but recent studies suggest that it is diverged into several more specialised species in addition to the generalist Albugo candida s.s.. Whereas these species cause the disease white blister rust in many...... crucifer plants, asymptomatic endophytic infections may be important in the epidemiology of others. One of the plant species attacked by Albugo sp. is the wild crucifer Barbarea vulgaris ssp. arcuata, which is diverged into two phytochemically and genetically different types with different geographical...... distributions in Europe. These were previously shown to differ strongly in propensity to develop white rust upon controlled infections in the greenhouse. Here, we analyse the phylogenetic relatedness of this local Albugo sp. field isolate to other species and lines of Albugo spp., including others collected...

  11. International Conference of Intelligence Computation and Evolutionary Computation ICEC 2012

    CERN Document Server

    Intelligence Computation and Evolutionary Computation

    2013-01-01

    2012 International Conference of Intelligence Computation and Evolutionary Computation (ICEC 2012) is held on July 7, 2012 in Wuhan, China. This conference is sponsored by Information Technology & Industrial Engineering Research Center.  ICEC 2012 is a forum for presentation of new research results of intelligent computation and evolutionary computation. Cross-fertilization of intelligent computation, evolutionary computation, evolvable hardware and newly emerging technologies is strongly encouraged. The forum aims to bring together researchers, developers, and users from around the world in both industry and academia for sharing state-of-art results, for exploring new areas of research and development, and to discuss emerging issues facing intelligent computation and evolutionary computation.

  12. Evolutionary Dynamics of Biological Auctions

    Science.gov (United States)

    Chatterjee, Krishnendu; Reiter, Johannes G.; Nowak, Martin A.

    2011-01-01

    Many scenarios in the living world, where individual organisms compete for winning positions (or resources), have properties of auctions. Here we study the evolution of bids in biological auctions. For each auction n individuals are drawn at random from a population of size N. Each individual makes a bid which entails a cost. The winner obtains a benefit of a certain value. Costs and benefits are translated into reproductive success (fitness). Therefore, successful bidding strategies spread in the population. We compare two types of auctions. In “biological all-pay auctions” the costs are the bid for every participating individual. In “biological second price all-pay auctions” the cost for everyone other than the winner is the bid, but the cost for the winner is the second highest bid. Second price all-pay auctions are generalizations of the “war of attrition” introduced by Maynard Smith. We study evolutionary dynamics in both types of auctions. We calculate pairwise invasion plots and evolutionarily stable distributions over the continuous strategy space. We find that the average bid in second price all-pay auctions is higher than in all-pay auctions, but the average cost for the winner is similar in both auctions. In both cases the average bid is a declining function of the number of participants, n. The more individuals participate in an auction the smaller is the chance of winning, and thus expensive bids must be avoided. PMID:22120126

  13. Natural pedagogy as evolutionary adaptation.

    Science.gov (United States)

    Csibra, Gergely; Gergely, György

    2011-04-12

    We propose that the cognitive mechanisms that enable the transmission of cultural knowledge by communication between individuals constitute a system of 'natural pedagogy' in humans, and represent an evolutionary adaptation along the hominin lineage. We discuss three kinds of arguments that support this hypothesis. First, natural pedagogy is likely to be human-specific: while social learning and communication are both widespread in non-human animals, we know of no example of social learning by communication in any other species apart from humans. Second, natural pedagogy is universal: despite the huge variability in child-rearing practices, all human cultures rely on communication to transmit to novices a variety of different types of cultural knowledge, including information about artefact kinds, conventional behaviours, arbitrary referential symbols, cognitively opaque skills and know-how embedded in means-end actions. Third, the data available on early hominin technological culture are more compatible with the assumption that natural pedagogy was an independently selected adaptive cognitive system than considering it as a by-product of some other human-specific adaptation, such as language. By providing a qualitatively new type of social learning mechanism, natural pedagogy is not only the product but also one of the sources of the rich cultural heritage of our species.

  14. Evolutionary rate variation and RNA secondary structure prediction

    DEFF Research Database (Denmark)

    Knudsen, B.; Andersen, E.S.; Damgaard, C.

    2004-01-01

    Predicting RNA secondary structure using evolutionary history can be carried out by using an alignment of related RNA sequences with conserved structure. Accurately determining evolutionary substitution rates for base pairs and single stranded nucleotides is a concern for methods based on this type...... by applying rates derived from tRNA and rRNA to the prediction of the much more rapidly evolving 5'-region of HIV-1. We find that the HIV-1 prediction is in agreement with experimental data, even though the relative evolutionary rate between A and G is significantly increased, both in stem and loop regions...

  15. Evolutionary games under incompetence.

    Science.gov (United States)

    Kleshnina, Maria; Filar, Jerzy A; Ejov, Vladimir; McKerral, Jody C

    2018-02-26

    The adaptation process of a species to a new environment is a significant area of study in biology. As part of natural selection, adaptation is a mutation process which improves survival skills and reproductive functions of species. Here, we investigate this process by combining the idea of incompetence with evolutionary game theory. In the sense of evolution, incompetence and training can be interpreted as a special learning process. With focus on the social side of the problem, we analyze the influence of incompetence on behavior of species. We introduce an incompetence parameter into a learning function in a single-population game and analyze its effect on the outcome of the replicator dynamics. Incompetence can change the outcome of the game and its dynamics, indicating its significance within what are inherently imperfect natural systems.

  16. Spore: Spawning Evolutionary Misconceptions?

    Science.gov (United States)

    Bean, Thomas E.; Sinatra, Gale M.; Schrader, P. G.

    2010-10-01

    The use of computer simulations as educational tools may afford the means to develop understanding of evolution as a natural, emergent, and decentralized process. However, special consideration of developmental constraints on learning may be necessary when using these technologies. Specifically, the essentialist (biological forms possess an immutable essence), teleological (assignment of purpose to living things and/or parts of living things that may not be purposeful), and intentionality (assumption that events are caused by an intelligent agent) biases may be reinforced through the use of computer simulations, rather than addressed with instruction. We examine the video game Spore for its depiction of evolutionary content and its potential to reinforce these cognitive biases. In particular, we discuss three pedagogical strategies to mitigate weaknesses of Spore and other computer simulations: directly targeting misconceptions through refutational approaches, targeting specific principles of scientific inquiry, and directly addressing issues related to models as cognitive tools.

  17. Environmental evolutionary graph theory.

    Science.gov (United States)

    Maciejewski, Wes; Puleo, Gregory J

    2014-11-07

    Understanding the influence of an environment on the evolution of its resident population is a major challenge in evolutionary biology. Great progress has been made in homogeneous population structures while heterogeneous structures have received relatively less attention. Here we present a structured population model where different individuals are best suited to different regions of their environment. The underlying structure is a graph: individuals occupy vertices, which are connected by edges. If an individual is suited for their vertex, they receive an increase in fecundity. This framework allows attention to be restricted to the spatial arrangement of suitable habitat. We prove some basic properties of this model and find some counter-intuitive results. Notably, (1) the arrangement of suitable sites is as important as their proportion, and (2) decreasing the proportion of suitable sites may result in a decrease in the fixation time of an allele. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. A randomized controlled study on the efficacy of a novel combination vaccine against enzootic pneumonia (Mycoplasma hyopneumoniae) and porcine Circovirus type 2 (PCV2) in the presence of strong maternally derived PCV2 immunity in pigs.

    Science.gov (United States)

    Tassis, Panagiotis D; Tsakmakidis, Ioannis; Papatsiros, Vassileios G; Koulialis, Dimitrios; Nell, Tom; Brellou, Georgia; Tzika, Eleni D

    2017-04-07

    Mycoplasma hyopneumoniae (M. hyo) and Porcine Circovirus Type 2 (PCV2) are major pathogens that cause significant health problems in swine worldwide. Maternal derived immunity (MDI) has been suggested as a significant immediate defence factor for newborn piglets and may interfere with piglet's vaccination-induced immunity. The study aimed to assess the efficacy of a novel combination vaccine (consisting of PCV2 subunits and inactivated M. hyo strain J), against PCV2 and M. hyo natural infection [Porcilis ® PCV M Hyo (MSD Animal Health, Boxmeer, the Netherlands)], in the presence of strong maternally derived PCV2 immunity (antibody titre averaged 11.08 log 2 ), under field conditions. The study was performed according to a controlled, randomized and blinded design in a Greek swine unit with Enzootic Pneumonia (EP) and subclinical PCV2 infection. In total, 600 healthy three-week-old suckling piglets were allocated randomly, either to treatment (vaccinated with the test product) or control group (injected with sterile buffered saline). Vaccination significantly reduced the severity of lung lesions at slaughter (lesions of cranio-ventral pulmonary consolidation) (P pigs. Furthermore, 25 g higher average daily weight gain (ADWG) was observed during the finishing phase (P < 0.001) and 18 g greater ADWG overall (P < 0.001). Results of LLS, PCV2 viremia and ADWG support the test product's efficacy in the face of strong maternally derived PCV2 immunity.

  19. Topics of Evolutionary Computation 2001

    DEFF Research Database (Denmark)

    Ursem, Rasmus Kjær

    This booklet contains the student reports from the course: Topics of Evolutionary Computation, Fall 2001, given by Thiemo Krink, Rene Thomsen and Rasmus K. Ursem......This booklet contains the student reports from the course: Topics of Evolutionary Computation, Fall 2001, given by Thiemo Krink, Rene Thomsen and Rasmus K. Ursem...

  20. Fixation Time for Evolutionary Graphs

    Science.gov (United States)

    Nie, Pu-Yan; Zhang, Pei-Ai

    Evolutionary graph theory (EGT) is recently proposed by Lieberman et al. in 2005. EGT is successful for explaining biological evolution and some social phenomena. It is extremely important to consider the time of fixation for EGT in many practical problems, including evolutionary theory and the evolution of cooperation. This study characterizes the time to asymptotically reach fixation.

  1. Evolutionary dynamics in structured populations

    Science.gov (United States)

    Nowak, Martin A.; Tarnita, Corina E.; Antal, Tibor

    2010-01-01

    Evolutionary dynamics shape the living world around us. At the centre of every evolutionary process is a population of reproducing individuals. The structure of that population affects evolutionary dynamics. The individuals can be molecules, cells, viruses, multicellular organisms or humans. Whenever the fitness of individuals depends on the relative abundance of phenotypes in the population, we are in the realm of evolutionary game theory. Evolutionary game theory is a general approach that can describe the competition of species in an ecosystem, the interaction between hosts and parasites, between viruses and cells, and also the spread of ideas and behaviours in the human population. In this perspective, we review the recent advances in evolutionary game dynamics with a particular emphasis on stochastic approaches in finite sized and structured populations. We give simple, fundamental laws that determine how natural selection chooses between competing strategies. We study the well-mixed population, evolutionary graph theory, games in phenotype space and evolutionary set theory. We apply these results to the evolution of cooperation. The mechanism that leads to the evolution of cooperation in these settings could be called ‘spatial selection’: cooperators prevail against defectors by clustering in physical or other spaces. PMID:20008382

  2. Open Issues in Evolutionary Robotics.

    Science.gov (United States)

    Silva, Fernando; Duarte, Miguel; Correia, Luís; Oliveira, Sancho Moura; Christensen, Anders Lyhne

    2016-01-01

    One of the long-term goals in evolutionary robotics is to be able to automatically synthesize controllers for real autonomous robots based only on a task specification. While a number of studies have shown the applicability of evolutionary robotics techniques for the synthesis of behavioral control, researchers have consistently been faced with a number of issues preventing the widespread adoption of evolutionary robotics for engineering purposes. In this article, we review and discuss the open issues in evolutionary robotics. First, we analyze the benefits and challenges of simulation-based evolution and subsequent deployment of controllers versus evolution on real robotic hardware. Second, we discuss specific evolutionary computation issues that have plagued evolutionary robotics: (1) the bootstrap problem, (2) deception, and (3) the role of genomic encoding and genotype-phenotype mapping in the evolution of controllers for complex tasks. Finally, we address the absence of standard research practices in the field. We also discuss promising avenues of research. Our underlying motivation is the reduction of the current gap between evolutionary robotics and mainstream robotics, and the establishment of evolutionary robotics as a canonical approach for the engineering of autonomous robots.

  3. Contemporary issues in evolutionary biology

    Indian Academy of Sciences (India)

    We are delighted to bring to the readers, a set of peer-reviewed papers on evolutionary biology, published as a special issue of the Journal of Genetics. These papers emanated from ruminations upon and discussions at the Foundations of. Evolutionary Theory: the Ongoing Synthesis meeting at Coorg, India, in February ...

  4. Evolutionary Explanations of Eating Disorders

    Directory of Open Access Journals (Sweden)

    Igor Kardum

    2008-12-01

    Full Text Available This article reviews several most important evolutionary mechanisms that underlie eating disorders. The first part clarifies evolutionary foundations of mental disorders and various mechanisms leading to their development. In the second part selective pressures and evolved adaptations causing contemporary epidemic of obesity as well as differences in dietary regimes and life-style between modern humans and their ancestors are described. Concerning eating disorders, a number of current evolutionary explanations of anorexia nervosa are presented together with their main weaknesses. Evolutionary explanations of eating disorders based on the reproductive suppression hypothesis and its variants derived from kin selection theory and the model of parental manipulation were elaborated. The sexual competition hypothesis of eating disorder, adapted to flee famine hypothesis as well as explanation based on the concept of social attention holding power and the need to belonging were also explained. The importance of evolutionary theory in modern conceptualization and research of eating disorders is emphasized.

  5. How competition affects evolutionary rescue

    Science.gov (United States)

    Osmond, Matthew Miles; de Mazancourt, Claire

    2013-01-01

    Populations facing novel environments can persist by adapting. In nature, the ability to adapt and persist will depend on interactions between coexisting individuals. Here we use an adaptive dynamic model to assess how the potential for evolutionary rescue is affected by intra- and interspecific competition. Intraspecific competition (negative density-dependence) lowers abundance, which decreases the supply rate of beneficial mutations, hindering evolutionary rescue. On the other hand, interspecific competition can aid evolutionary rescue when it speeds adaptation by increasing the strength of selection. Our results clarify this point and give an additional requirement: competition must increase selection pressure enough to overcome the negative effect of reduced abundance. We therefore expect evolutionary rescue to be most likely in communities which facilitate rapid niche displacement. Our model, which aligns to previous quantitative and population genetic models in the absence of competition, provides a first analysis of when competitors should help or hinder evolutionary rescue. PMID:23209167

  6. EVOLUTIONARY TRACKS OF TIDALLY STIRRED DISKY DWARF GALAXIES

    International Nuclear Information System (INIS)

    Lokas, Ewa L.; Kazantzidis, Stelios; Mayer, Lucio

    2011-01-01

    Using collisionless N-body simulations, we investigate the tidal evolution of late-type, rotationally supported dwarfs inside Milky Way sized host galaxies. Our study focuses on a wide variety of dwarf orbital configurations and initial structures. During the evolution, the disky dwarfs undergo strong mass loss, the stellar disks are transformed into spheroids, and rotation is replaced by random motions of the stars. Thus, the late-type progenitors are transformed into early-type dwarfs as envisioned by the tidal stirring model for the formation of dwarf spheroidal (dSph) galaxies in the Local Group. We determine the photometric properties of the dwarfs, including the total visual magnitude, the half-light radius, and the central surface brightness as they would be measured by an observer near the galactic center. Special emphasis is also placed on studying their kinematics and shapes. We demonstrate that the measured values are biased by a number of observational effects including the increasing angle of the observation cone near the orbital pericenter, the fact that away from the pericenter the tidal tails are typically oriented along the line of sight, and the fact that for most of the evolution the stellar components of the dwarfs are triaxial ellipsoids whose major axis tumbles with respect to the line of sight. Finally, we compare the measured properties of the simulated dwarfs to those of dwarf galaxies in the Local Group. The evolutionary tracks of the dwarfs in different parameter planes and the correlations between their different properties, especially the total magnitude and the surface brightness, strongly suggest that present-day dSph galaxies may have indeed formed from late-type progenitors as proposed by the tidal stirring scenario.

  7. On the evolutionary origins of equity.

    Directory of Open Access Journals (Sweden)

    Stéphane Debove

    Full Text Available Equity, defined as reward according to contribution, is considered a central aspect of human fairness in both philosophical debates and scientific research. Despite large amounts of research on the evolutionary origins of fairness, the evolutionary rationale behind equity is still unknown. Here, we investigate how equity can be understood in the context of the cooperative environment in which humans evolved. We model a population of individuals who cooperate to produce and divide a resource, and choose their cooperative partners based on how they are willing to divide the resource. Agent-based simulations, an analytical model, and extended simulations using neural networks provide converging evidence that equity is the best evolutionary strategy in such an environment: individuals maximize their fitness by dividing benefits in proportion to their own and their partners' relative contribution. The need to be chosen as a cooperative partner thus creates a selection pressure strong enough to explain the evolution of preferences for equity. We discuss the limitations of our model, the discrepancies between its predictions and empirical data, and how interindividual and intercultural variability fit within this framework.

  8. Gillespie eco-evolutionary models (GEMs) reveal the role of heritable trait variation in eco-evolutionary dynamics.

    Science.gov (United States)

    DeLong, John P; Gibert, Jean P

    2016-02-01

    Heritable trait variation is a central and necessary ingredient of evolution. Trait variation also directly affects ecological processes, generating a clear link between evolutionary and ecological dynamics. Despite the changes in variation that occur through selection, drift, mutation, and recombination, current eco-evolutionary models usually fail to track how variation changes through time. Moreover, eco-evolutionary models assume fitness functions for each trait and each ecological context, which often do not have empirical validation. We introduce a new type of model, Gillespie eco-evolutionary models (GEMs), that resolves these concerns by tracking distributions of traits through time as eco-evolutionary dynamics progress. This is done by allowing change to be driven by the direct fitness consequences of model parameters within the context of the underlying ecological model, without having to assume a particular fitness function. GEMs work by adding a trait distribution component to the standard Gillespie algorithm - an approach that models stochastic systems in nature that are typically approximated through ordinary differential equations. We illustrate GEMs with the Rosenzweig-MacArthur consumer-resource model. We show not only how heritable trait variation fuels trait evolution and influences eco-evolutionary dynamics, but also how the erosion of variation through time may hinder eco-evolutionary dynamics in the long run. GEMs can be developed for any parameter in any ordinary differential equation model and, furthermore, can enable modeling of multiple interacting traits at the same time. We expect GEMs will open the door to a new direction in eco-evolutionary and evolutionary modeling by removing long-standing modeling barriers, simplifying the link between traits, fitness, and dynamics, and expanding eco-evolutionary treatment of a greater diversity of ecological interactions. These factors make GEMs much more than a modeling advance, but an important

  9. Social traits, social networks and evolutionary biology.

    Science.gov (United States)

    Fisher, D N; McAdam, A G

    2017-12-01

    The social environment is both an important agent of selection for most organisms, and an emergent property of their interactions. As an aggregation of interactions among members of a population, the social environment is a product of many sets of relationships and so can be represented as a network or matrix. Social network analysis in animals has focused on why these networks possess the structure they do, and whether individuals' network traits, representing some aspect of their social phenotype, relate to their fitness. Meanwhile, quantitative geneticists have demonstrated that traits expressed in a social context can depend on the phenotypes and genotypes of interacting partners, leading to influences of the social environment on the traits and fitness of individuals and the evolutionary trajectories of populations. Therefore, both fields are investigating similar topics, yet have arrived at these points relatively independently. We review how these approaches are diverged, and yet how they retain clear parallelism and so strong potential for complementarity. This demonstrates that, despite separate bodies of theory, advances in one might inform the other. Techniques in network analysis for quantifying social phenotypes, and for identifying community structure, should be useful for those studying the relationship between individual behaviour and group-level phenotypes. Entering social association matrices into quantitative genetic models may also reduce bias in heritability estimates, and allow the estimation of the influence of social connectedness on trait expression. Current methods for measuring natural selection in a social context explicitly account for the fact that a trait is not necessarily the property of a single individual, something the network approaches have not yet considered when relating network metrics to individual fitness. Harnessing evolutionary models that consider traits affected by genes in other individuals (i.e. indirect genetic

  10. Is Exercise Really Medicine? An Evolutionary Perspective.

    Science.gov (United States)

    Lieberman, Daniel E

    2015-01-01

    An evolutionary perspective helps evaluate the extent to which exercise is medicine and to explain the exercise paradox: why people tend to avoid exercise despite its benefits. Many lines of evidence indicate that humans evolved to be adapted for regular, moderate amounts of endurance physical activity into late age. However, because energy from food was limited, humans also were selected to avoid unnecessary exertion, and most anatomical and physiological systems evolved to require stimuli from physical activity to adjust capacity to demand. Consequently, selection never operated to cope with the long-term effects of chronic inactivity. However, because all adaptations involve trade-offs, there is no evolutionary-determined dose or type of physical activity that will optimize health. Furthermore, because humans evolved to be active for play or necessity, efforts to promote exercise will require altering environments in ways that nudge or even compel people to be active and to make exercise fun.

  11. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  12. Evolutionary patterns in coiled-coils.

    Science.gov (United States)

    Surkont, Jaroslaw; Pereira-Leal, Jose B

    2015-01-10

    Models of protein evolution are used to describe evolutionary processes, for phylogenetic analyses and homology detection. Widely used general models of protein evolution are biased toward globular domains and lack resolution to describe evolutionary processes for other protein types. As three-dimensional structure is a major constraint to protein evolution, specific models have been proposed for other types of proteins. Here, we consider evolutionary patterns in coiled-coil forming proteins. Coiled-coils are widespread structural domains, formed by a repeated motif of seven amino acids (heptad repeat). Coiled-coil forming proteins are frequently rods and spacers, structuring both the intracellular and the extracellular spaces that often form protein interaction interfaces. We tested the hypothesis that due to their specific structure the associated evolutionary constraints differ from those of globular proteins. We showed that substitution patterns in coiled-coil regions are different than those observed in globular regions, beyond the simple heptad repeat. Based on these substitution patterns we developed a coiled-coil specific (CC) model that in the context of phylogenetic reconstruction outperforms general models in tree likelihood, often leading to different topologies. For multidomain proteins containing both a coiled-coil region and a globular domain, we showed that a combination of the CC model and a general one gives higher likelihoods than a single model. Finally, we showed that the model can be used for homology detection to increase search sensitivity for coiled-coil proteins. The CC model, software, and other supplementary materials are available at http://www.evocell.org/cgl/resources (last accessed January 29, 2015). © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  13. Increase in homeostasis model assessment of insulin resistance (HOMA-IR) had a strong impact on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion: the Saku study.

    Science.gov (United States)

    Morimoto, Akiko; Tatsumi, Yukako; Soyano, Fumie; Miyamatsu, Naomi; Sonoda, Nao; Godai, Kayo; Ohno, Yuko; Noda, Mitsuhiko; Deura, Kijyo

    2014-01-01

    Our aim was to assess the impact of increase in homeostasis model assessment of insulin resistance (HOMA-IR) on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion (IIS). This study included 2,209 participants aged 30-69 without diabetes at baseline who underwent comprehensive medical check-ups between April 2006 and March 2007 at Saku Central Hospital. Participants were classified into eight groups according to the combination of baseline IIS status (non-IIS and IIS) and category of HOMA-IR change between the baseline and follow-up examinations (decrease, no change/small increase, moderate increase, and large increase). Type 2 diabetes was determined from fasting and 2 h post-load plasma glucose concentrations at the follow-up examination between April 2009 and March 2011. At baseline, 669 individuals (30.3%) were classified as having IIS. At follow-up, 74 individuals developed type 2 diabetes. After adjusting for confounding factors including baseline HOMA-IR values, the multivariable-adjusted odds ratios (95% confidence intervals) for type 2 diabetes in the non-IIS with a decrease (mean change in HOMA-IR: -0.47), non-IIS with a moderate increase (mean change in HOMA-IR: 0.28), non-IIS with a large increase (mean change in HOMA-IR: 0.83), IIS with a decrease (mean change in HOMA-IR: -0.36), IIS with no change/small increase (mean change in HOMA-IR: 0.08), IIS with a moderate increase (mean change in HOMA-IR: 0.27), and IIS with a large increase (mean change in HOMA-IR: 0.73) groups, relative to the non-IIS with no change/small increase (mean change in HOMA-IR: 0.08) group were 0.23 (0.04, 1.11), 1.22 (0.26, 5.72), 2.01 (0.70, 6.46), 1.37 (0.32, 4.28), 3.60 (0.83, 15.57), 5.24 (1.34, 20.52), and 7.01 (1.75, 24.18), respectively. Moderate and large increases in HOMA-IR had a strong impact on the development of type 2 diabetes among individuals with IIS in this Japanese population.

  14. Increase in homeostasis model assessment of insulin resistance (HOMA-IR had a strong impact on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion: the Saku study.

    Directory of Open Access Journals (Sweden)

    Akiko Morimoto

    Full Text Available Our aim was to assess the impact of increase in homeostasis model assessment of insulin resistance (HOMA-IR on the development of type 2 diabetes in Japanese individuals with impaired insulin secretion (IIS. This study included 2,209 participants aged 30-69 without diabetes at baseline who underwent comprehensive medical check-ups between April 2006 and March 2007 at Saku Central Hospital. Participants were classified into eight groups according to the combination of baseline IIS status (non-IIS and IIS and category of HOMA-IR change between the baseline and follow-up examinations (decrease, no change/small increase, moderate increase, and large increase. Type 2 diabetes was determined from fasting and 2 h post-load plasma glucose concentrations at the follow-up examination between April 2009 and March 2011. At baseline, 669 individuals (30.3% were classified as having IIS. At follow-up, 74 individuals developed type 2 diabetes. After adjusting for confounding factors including baseline HOMA-IR values, the multivariable-adjusted odds ratios (95% confidence intervals for type 2 diabetes in the non-IIS with a decrease (mean change in HOMA-IR: -0.47, non-IIS with a moderate increase (mean change in HOMA-IR: 0.28, non-IIS with a large increase (mean change in HOMA-IR: 0.83, IIS with a decrease (mean change in HOMA-IR: -0.36, IIS with no change/small increase (mean change in HOMA-IR: 0.08, IIS with a moderate increase (mean change in HOMA-IR: 0.27, and IIS with a large increase (mean change in HOMA-IR: 0.73 groups, relative to the non-IIS with no change/small increase (mean change in HOMA-IR: 0.08 group were 0.23 (0.04, 1.11, 1.22 (0.26, 5.72, 2.01 (0.70, 6.46, 1.37 (0.32, 4.28, 3.60 (0.83, 15.57, 5.24 (1.34, 20.52, and 7.01 (1.75, 24.18, respectively. Moderate and large increases in HOMA-IR had a strong impact on the development of type 2 diabetes among individuals with IIS in this Japanese population.

  15. Strong Cosmic Censorship

    Science.gov (United States)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  16. Extinction dynamics from metastable coexistences in an evolutionary game

    Science.gov (United States)

    Park, Hye Jin; Traulsen, Arne

    2017-10-01

    Deterministic evolutionary game dynamics can lead to stable coexistences of different types. Stochasticity, however, drives the loss of such coexistences. This extinction is usually accompanied by population size fluctuations. We investigate the most probable extinction trajectory under such fluctuations by mapping a stochastic evolutionary model to a problem of classical mechanics using the Wentzel-Kramers-Brillouin (WKB) approximation. Our results show that more abundant types in a coexistence may be more likely to go extinct first, in good agreement with previous results. The distance between the coexistence and extinction points is not a good predictor of extinction either. Instead, the WKB method correctly predicts the type going extinct first.

  17. Evolutionary Tracks for Betelgeuse

    Science.gov (United States)

    Dolan, Michelle M.; Mathews, Grant J.; Lam, Doan Duc; Quynh Lan, Nguyen; Herczeg, Gregory J.; Dearborn, David S. P.

    2016-03-01

    We have constructed a series of nonrotating quasi-hydrostatic evolutionary models for the M2 Iab supergiant Betelgeuse (α Orionis). Our models are constrained by multiple observed values for the temperature, luminosity, surface composition, and mass loss for this star, along with the parallax distance and high-resolution imagery that determines its radius. We have then applied our best-fit models to analyze the observed variations in surface luminosity and the size of detected surface bright spots as the result of up-flowing convective material from regions of high temperature in the surface convective zone. We also attempt to explain the intermittently observed periodic variability in a simple radial linear adiabatic pulsation model. Based on the best fit to all observed data, we suggest a best progenitor mass estimate of {20}-3+5 {M}⊙ and a current age from the start of the zero-age main sequence of 8.0-8.5 Myr based on the observed ejected mass while on the giant branch.

  18. Industrial Applications of Evolutionary Algorithms

    CERN Document Server

    Sanchez, Ernesto; Tonda, Alberto

    2012-01-01

    This book is intended as a reference both for experienced users of evolutionary algorithms and for researchers that are beginning to approach these fascinating optimization techniques. Experienced users will find interesting details of real-world problems, and advice on solving issues related to fitness computation, modeling and setting appropriate parameters to reach optimal solutions. Beginners will find a thorough introduction to evolutionary computation, and a complete presentation of all evolutionary algorithms exploited to solve different problems. The book could fill the gap between the

  19. Extrapolating Weak Selection in Evolutionary Games

    Science.gov (United States)

    Wu, Bin; García, Julián; Hauert, Christoph; Traulsen, Arne

    2013-01-01

    In evolutionary games, reproductive success is determined by payoffs. Weak selection means that even large differences in game outcomes translate into small fitness differences. Many results have been derived using weak selection approximations, in which perturbation analysis facilitates the derivation of analytical results. Here, we ask whether results derived under weak selection are also qualitatively valid for intermediate and strong selection. By “qualitatively valid” we mean that the ranking of strategies induced by an evolutionary process does not change when the intensity of selection increases. For two-strategy games, we show that the ranking obtained under weak selection cannot be carried over to higher selection intensity if the number of players exceeds two. For games with three (or more) strategies, previous examples for multiplayer games have shown that the ranking of strategies can change with the intensity of selection. In particular, rank changes imply that the most abundant strategy at one intensity of selection can become the least abundant for another. We show that this applies already to pairwise interactions for a broad class of evolutionary processes. Even when both weak and strong selection limits lead to consistent predictions, rank changes can occur for intermediate intensities of selection. To analyze how common such games are, we show numerically that for randomly drawn two-player games with three or more strategies, rank changes frequently occur and their likelihood increases rapidly with the number of strategies . In particular, rank changes are almost certain for , which jeopardizes the predictive power of results derived for weak selection. PMID:24339769

  20. Evolutionary Origin of Euglena.

    Science.gov (United States)

    Zakryś, Bożena; Milanowski, Rafał; Karnkowska, Anna

    2017-01-01

    Euglenids (Excavata, Discoba, Euglenozoa, Euglenida) is a group of free-living, single-celled flagellates living in the aquatic environments. The uniting and unique morphological feature of euglenids is the presence of a cell covering called the pellicle. The morphology and organization of the pellicle correlate well with the mode of nutrition and cell movement. Euglenids exhibit diverse modes of nutrition, including phagotrophy and photosynthesis. Photosynthetic species (Euglenophyceae) constitute a single subclade within euglenids. Their plastids embedded by three membranes arose as the result of a secondary endosymbiosis between phagotrophic eukaryovorous euglenid and the Pyramimonas-related green alga. Within photosynthetic euglenids three evolutionary lineages can be distinguished. The most basal lineage is formed by one mixotrophic species, Rapaza viridis. Other photosynthetic euglenids are split into two groups: predominantly marine Eutreptiales and freshwater Euglenales. Euglenales are divided into two families: Phacaceae, comprising three monophyletic genera (Discoplastis, Lepocinclis, Phacus) and Euglenaceae with seven monophyletic genera (Euglenaformis, Euglenaria, Colacium, Cryptoglena, Strombomonas, Trachelomonas, Monomorphina) and polyphyletic genus Euglena. For 150 years researchers have been studying Euglena based solely on morphological features what resulted in hundreds of descriptions of new taxa and many artificial intra-generic classification systems. In spite of the progress towards defining Euglena, it still remains polyphyletic and morphologically almost undistinguishable from members of the recently described genus Euglenaria; members of both genera have cells undergoing metaboly (dynamic changes in cell shape), large chloroplasts with pyrenoids and monomorphic paramylon grains. Model organisms Euglena gracilis Klebs, the species of choice for addressing fundamental questions in eukaryotic biochemistry, cell and molecular biology, is a

  1. Molluscan Evolutionary Genomics

    Energy Technology Data Exchange (ETDEWEB)

    Simison, W. Brian; Boore, Jeffrey L.

    2005-12-01

    In the last 20 years there have been dramatic advances in techniques of high-throughput DNA sequencing, most recently accelerated by the Human Genome Project, a program that has determined the three billion base pair code on which we are based. Now this tremendous capability is being directed at other genome targets that are being sampled across the broad range of life. This opens up opportunities as never before for evolutionary and organismal biologists to address questions of both processes and patterns of organismal change. We stand at the dawn of a new 'modern synthesis' period, paralleling that of the early 20th century when the fledgling field of genetics first identified the underlying basis for Darwin's theory. We must now unite the efforts of systematists, paleontologists, mathematicians, computer programmers, molecular biologists, developmental biologists, and others in the pursuit of discovering what genomics can teach us about the diversity of life. Genome-level sampling for mollusks to date has mostly been limited to mitochondrial genomes and it is likely that these will continue to provide the best targets for broad phylogenetic sampling in the near future. However, we are just beginning to see an inroad into complete nuclear genome sequencing, with several mollusks and other eutrochozoans having been selected for work about to begin. Here, we provide an overview of the state of molluscan mitochondrial genomics, highlight a few of the discoveries from this research, outline the promise of broadening this dataset, describe upcoming projects to sequence whole mollusk nuclear genomes, and challenge the community to prepare for making the best use of these data.

  2. Defining fitness in evolutionary models

    Indian Academy of Sciences (India)

    jgen/087/04/0339-0348. Keywords. fitness; invasion exponent; adaptive dynamics; game theory; Lyapunov exponent; invasibility; Malthusian parameter. Abstract. The analysis of evolutionary models requires an appropriate definition for fitness.

  3. Evolutionary Processes and Mental Deficiency

    Science.gov (United States)

    Spitz, Herman H.

    1973-01-01

    The author hypothesizes that central nervous system damage of deficiency associated with mental retardation affects primarily those cortical processes which developed at a late stage in man's evolutionary history. (Author)

  4. Evolutionary computation for reinforcement learning

    NARCIS (Netherlands)

    Whiteson, S.; Wiering, M.; van Otterlo, M.

    2012-01-01

    Algorithms for evolutionary computation, which simulate the process of natural selection to solve optimization problems, are an effective tool for discovering high-performing reinforcement-learning policies. Because they can automatically find good representations, handle continuous action spaces,

  5. Strong Arcwise Connectedness

    OpenAIRE

    Espinoza, Benjamin; Gartside, Paul; Kovan-Bakan, Merve; Mamatelashvili, Ana

    2012-01-01

    A space is `n-strong arc connected' (n-sac) if for any n points in the space there is an arc in the space visiting them in order. A space is omega-strong arc connected (omega-sac) if it is n-sac for all n. We study these properties in finite graphs, regular continua, and rational continua. There are no 4-sac graphs, but there are 3-sac graphs and graphs which are 2-sac but not 3-sac. For every n there is an n-sac regular continuum, but no regular continuum is omega-sac. There is an omega-sac ...

  6. Abortion: Strong's counterexamples fail

    DEFF Research Database (Denmark)

    Di Nucci, Ezio

    2009-01-01

    This paper shows that the counterexamples proposed by Strong in 2008 in the Journal of Medical Ethics to Marquis's argument against abortion fail. Strong's basic idea is that there are cases--for example, terminally ill patients--where killing an adult human being is prima facie seriously morally......'s scenarios have some valuable future or admitted that killing them is not seriously morally wrong. Finally, if "valuable future" is interpreted as referring to objective standards, one ends up with implausible and unpalatable moral claims....

  7. Eco-evolutionary feedbacks in community and ecosystem ecology: interactions between the ecological theatre and the evolutionary play

    Science.gov (United States)

    Post, David M.; Palkovacs, Eric P.

    2009-01-01

    Interactions between natural selection and environmental change are well recognized and sit at the core of ecology and evolutionary biology. Reciprocal interactions between ecology and evolution, eco-evolutionary feedbacks, are less well studied, even though they may be critical for understanding the evolution of biological diversity, the structure of communities and the function of ecosystems. Eco-evolutionary feedbacks require that populations alter their environment (niche construction) and that those changes in the environment feed back to influence the subsequent evolution of the population. There is strong evidence that organisms influence their environment through predation, nutrient excretion and habitat modification, and that populations evolve in response to changes in their environment at time-scales congruent with ecological change (contemporary evolution). Here, we outline how the niche construction and contemporary evolution interact to alter the direction of evolution and the structure and function of communities and ecosystems. We then present five empirical systems that highlight important characteristics of eco-evolutionary feedbacks: rotifer–algae chemostats; alewife–zooplankton interactions in lakes; guppy life-history evolution and nutrient cycling in streams; avian seed predators and plants; and tree leaf chemistry and soil processes. The alewife–zooplankton system provides the most complete evidence for eco-evolutionary feedbacks, but other systems highlight the potential for eco-evolutionary feedbacks in a wide variety of natural systems. PMID:19414476

  8. Evolutionary computation for trading systems

    OpenAIRE

    Kaucic, Massimiliano

    2008-01-01

    2007/2008 Evolutionary computations, also called evolutionary algorithms, consist of several heuristics, which are able to solve optimization tasks by imitating some aspects of natural evolution. They may use different levels of abstraction, but they are always working on populations of possible solutions for a given task. The basic idea is that if only those individuals of a population which meet a certain selection criteria reproduce, while the remaining individuals die, the ...

  9. Freud: the first evolutionary psychologist?

    Science.gov (United States)

    LeCroy, D

    2000-04-01

    An evolutionary perspective on attachment theory and psychoanalytic theory brings these two fields together in interesting ways. Application of the evolutionary principle of parent-offspring conflict to attachment theory suggests that attachment styles represent context-sensitive, evolved (adaptive) behaviors. In addition, an emphasis on offspring counter-strategies to adult reproductive strategies leads to consideration of attachment styles as overt manifestations of psychodynamic mediating processes, including the defense mechanisms of repression and reaction formation.

  10. Ecological interactions drive evolutionary loss of traits.

    Science.gov (United States)

    Ellers, Jacintha; Kiers, E Toby; Currie, Cameron R; McDonald, Bradon R; Visser, Bertanne

    2012-10-01

    Loss of traits can dramatically alter the fate of species. Evidence is rapidly accumulating that the prevalence of trait loss is grossly underestimated. New findings demonstrate that traits can be lost without affecting the external phenotype, provided the lost function is compensated for by species interactions. This is important because trait loss can tighten the ecological relationship between partners, affecting the maintenance of species interactions. Here, we develop a new perspective on so-called `compensated trait loss' and how this type of trait loss may affect the evolutionary dynamics between interacting organisms. We argue that: (1) the frequency of compensated trait loss is currently underestimated because it can go unnoticed as long as ecological interactions are maintained; (2) by analysing known cases of trait loss, specific factors promoting compensated trait loss can be identified and (3) genomic sequencing is a key way forwards in detecting compensated trait loss. We present a comprehensive literature survey showing that compensated trait loss is taxonomically widespread, can involve essential traits, and often occurs as replicated evolutionary events. Despite its hidden nature, compensated trait loss is important in directing evolutionary dynamics of ecological relationships and has the potential to change facultative ecological interactions into obligatory ones. © 2012 Blackwell Publishing Ltd/CNRS.

  11. Evolutionary games on multilayer networks: a colloquium

    Science.gov (United States)

    Wang, Zhen; Wang, Lin; Szolnoki, Attila; Perc, Matjaž

    2015-05-01

    Networks form the backbone of many complex systems, ranging from the Internet to human societies. Accordingly, not only is the range of our interactions limited and thus best described and modeled by networks, it is also a fact that the networks that are an integral part of such models are often interdependent or even interconnected. Networks of networks or multilayer networks are therefore a more apt description of social systems. This colloquium is devoted to evolutionary games on multilayer networks, and in particular to the evolution of cooperation as one of the main pillars of modern human societies. We first give an overview of the most significant conceptual differences between single-layer and multilayer networks, and we provide basic definitions and a classification of the most commonly used terms. Subsequently, we review fascinating and counterintuitive evolutionary outcomes that emerge due to different types of interdependencies between otherwise independent populations. The focus is on coupling through the utilities of players, through the flow of information, as well as through the popularity of different strategies on different network layers. The colloquium highlights the importance of pattern formation and collective behavior for the promotion of cooperation under adverse conditions, as well as the synergies between network science and evolutionary game theory.

  12. Altered Daytime Fluctuation Pattern of Plasminogen Activator Inhibitor 1 in Type 2 Diabetes Patients with Coronary Artery Disease: A Strong Association with Persistently Elevated Plasma Insulin, Increased Insulin Resistance, and Abdominal Obesity

    Directory of Open Access Journals (Sweden)

    Katarina Lalić

    2015-01-01

    Full Text Available This study was aimed at investigating daily fluctuation of PAI-1 levels in relation to insulin resistance (IR and daily profile of plasma insulin and glucose levels in 26 type 2 diabetic (T2D patients with coronary artery disease (CAD (group A, 10 T2D patients without CAD (group B, 12 nondiabetics with CAD (group C, and 12 healthy controls (group D. The percentage of PAI-1 decrease was lower in group A versus group B (4.4 ± 2.7 versus 35.0 ± 5.4%; P<0.05 and in C versus D (14.0 ± 5.8 versus 44.7 ± 3.1%; P<0.001. HOMA-IR was higher in group A versus group B (P<0.05 and in C versus D (P<0.01. Simultaneously, AUCs of PAI-1 and insulin were higher in group A versus group B (P<0.05 and in C versus D (P<0.01, while AUC of glucose did not differ between groups. In multiple regression analysis waist-to-hip ratio and AUC of insulin were independent determinants of decrease in PAI-1. The altered diurnal fluctuation of PAI-1, especially in T2D with CAD, might be strongly influenced by a prolonged exposure to hyperinsulinemia in the settings of increased IR and abdominal obesity, facilitating altogether an accelerated atherosclerosis.

  13. An Evolutionary Game Theory Model of Revision-Resistant Motivations and Strategic Reasoning

    National Research Council Canada - National Science Library

    DeLancey, Craig

    2008-01-01

    Strong reciprocity and other forms of cooperation with non-kin in large groups and in one-time social interactions is difficult to explain with traditional economic or with simple evolutionary accounts...

  14. A strong comeback

    International Nuclear Information System (INIS)

    Marier, D.

    1992-01-01

    This article presents the results of a financial rankings survey which show a strong economic activity in the independent energy industry. The topics of the article include advisor turnover, overseas banks, and the increase in public offerings. The article identifies the top project finance investors for new projects and restructurings and rankings for lenders

  15. Evolutionary relationships between papovaviruses and their hosts.

    Science.gov (United States)

    Scherneck, S; Feunteun, J; Vogel, F; Boettger, M; Krause, H; Prokoph, H; Zimmermann, W; Geissler, E

    1983-01-01

    The papovaviridae family consists of two genera, the papillomaviruses (PV) and the polyomaviruses (Py-V). Both genera are distinguished by morphological (larger sizes of the PV) and several biological characteristics. The genomes of either of the two genera share highly conserved DNA regions and a common antigenic determinant, located in their major capsid polypeptides. On the basis of these data an evolutionary relationship among the members of PV and Py-V, respectively, has been suggested. No homology has been found for either DNA- or protein sequences between PV and Py-V and the question of a common ancestor for both viral genera remains open. We have started to characterize the genome of a papilloma producing papovavirus of the Syrian hamster (HaPV). Most of the known biological characteristics of the HaPV suggest it should be classified as a papilloma-like virus. However, the molecular weight of about 3.5 X 10(6) daltons found for the circular duplex DNA lies within the range given for SV 40 and polyoma virus (Py). Analysis of the HaPV genome by cleavage with 21 different restriction endonucleases, location of specific binding sites of phage T 4 gene 32 protein and E. coli RNA polymerase on the viral DNA demonstrated that the HaPV differed distinctly from all other currently known papovaviruses. The HaPV genome was also analyzed by filter hybridization and electron microscopy under conditions of varied stringency for nucleotide sequence homology with the genomes of different papovaviruses of both genera. Whereas no homologous DNA regions could be found between the genomes of HaPV and the human PV types 1 and 4, only under nonstringent conditions (Tm-43 degrees C) stable hybrids were formed between HaPV-, SV 40- and the DNA of a PV isolated from Mastomys natalensis (MnPV). On the other hand extensive homology was detected between the genomes of HaPV and Py even under stringent hybridization conditions (Tm-28 degrees C). The homologous DNA segments mapped on the

  16. Strong Electroweak Symmetry Breaking

    CERN Document Server

    Grinstein, Benjamin

    2011-01-01

    Models of spontaneous breaking of electroweak symmetry by a strong interaction do not have fine tuning/hierarchy problem. They are conceptually elegant and use the only mechanism of spontaneous breaking of a gauge symmetry that is known to occur in nature. The simplest model, minimal technicolor with extended technicolor interactions, is appealing because one can calculate by scaling up from QCD. But it is ruled out on many counts: inappropriately low quark and lepton masses (or excessive FCNC), bad electroweak data fits, light scalar and vector states, etc. However, nature may not choose the minimal model and then we are stuck: except possibly through lattice simulations, we are unable to compute and test the models. In the LHC era it therefore makes sense to abandon specific models (of strong EW breaking) and concentrate on generic features that may indicate discovery. The Technicolor Straw Man is not a model but a parametrized search strategy inspired by a remarkable generic feature of walking technicolor,...

  17. Can evolutionary convergence be tested on Europa?

    International Nuclear Information System (INIS)

    Chela-Flores, Julian

    2002-09-01

    A major objective in solar system exploration has to be the insertion of appropriate biology-oriented experiments in future missions. We discuss various reasons for suggesting that this type of research be considered a high priority for feasibility studies and, subsequently, for technological development of appropriate melters and submersibles. With the assumption that Darwin's theory is valid for the evolution of life anywhere in the universe, various degrees of convergent phenomena argue in favor of the conjecture that universal evolution of intelligent behavior is just a matter of time and preservation of steady planetary conditions. A preliminary test of this conjecture is feasible with experiments involving evolutionary biosignatures on Europa. (author)

  18. Plasmons in strong superconductors

    International Nuclear Information System (INIS)

    Baldo, M.; Ducoin, C.

    2011-01-01

    We present a study of the possible plasmon excitations that can occur in systems where strong superconductivity is present. In these systems the plasmon energy is comparable to or smaller than the pairing gap. As a prototype of these systems we consider the proton component of Neutron Star matter just below the crust when electron screening is not taken into account. For the realistic case we consider in detail the different aspects of the elementary excitations when the proton, electron components are considered within the Random-Phase Approximation generalized to the superfluid case, while the influence of the neutron component is considered only at qualitative level. Electron screening plays a major role in modifying the proton spectrum and spectral function. At the same time the electron plasmon is strongly modified and damped by the indirect coupling with the superfluid proton component, even at moderately low values of the gap. The excitation spectrum shows the interplay of the different components and their relevance for each excitation modes. The results are relevant for neutrino physics and thermodynamical processes in neutron stars. If electron screening is neglected, the spectral properties of the proton component show some resemblance with the physical situation in high-T c superconductors, and we briefly discuss similarities and differences in this connection. In a general prospect, the results of the study emphasize the role of Coulomb interaction in strong superconductors.

  19. Massive stars in advanced evolutionary stages, and the progenitor of GW150914

    Science.gov (United States)

    Hamann, Wolf-Rainer; Oskinova, Lidia; Todt, Helge; Sander, Andreas; Hainich, Rainer; Shenar, Tomer; Ramachandran, Varsha

    2017-11-01

    The recent discovery of a gravitational wave from the merging of two black holes of about 30 solar masses each challenges our incomplete understanding of massive stars and their evolution. Critical ingredients comprise mass-loss, rotation, magnetic fields, internal mixing, and mass transfer in close binary systems. The imperfect knowledge of these factors implies large uncertainties for models of stellar populations and their feedback. In this contribution we summarize our empirical studies of Wolf-Rayet populations at different metallicities by means of modern non-LTE stellar atmosphere models, and confront these results with the predictions of stellar evolution models. At the metallicity of our Galaxy, stellar winds are probably too strong to leave remnant masses as high as ~30 M⊙, but given the still poor agreement between evolutionary tracks and observation even this conclusion is debatable. At the low metallicity of the Small Magellanic Cloud, all WN stars which are (at least now) single are consistent with evolving quasi-homogeneously. O and B-type stars, in contrast, seem to comply with standard evolutionary models without strong internal mixing. Close binaries which avoided early merging could evolve quasi-homogeneously and lead to close compact remnants of relatively high masses that merge within a Hubble time.

  20. Fixation times in evolutionary games under weak selection

    International Nuclear Information System (INIS)

    Altrock, Philipp M; Traulsen, Arne

    2009-01-01

    In evolutionary game dynamics, reproductive success increases with the performance in an evolutionary game. If strategy A performs better than strategy B, strategy A will spread in the population. Under stochastic dynamics, a single mutant will sooner or later take over the entire population or go extinct. We analyze the mean exit times (or average fixation times) associated with this process. We show analytically that these times depend on the payoff matrix of the game in an amazingly simple way under weak selection, i.e. strong stochasticity: the payoff difference Δπ is a linear function of the number of A individuals i, Δπ=u i+v. The unconditional mean exit time depends only on the constant term v. Given that a single A mutant takes over the population, the corresponding conditional mean exit time depends only on the density dependent term u. We demonstrate this finding for two commonly applied microscopic evolutionary processes.

  1. Evolutionary competition between boundedly rational behavioral rules in oligopoly games

    International Nuclear Information System (INIS)

    Cerboni Baiardi, Lorenzo; Lamantia, Fabio; Radi, Davide

    2015-01-01

    In this paper, we propose an evolutionary model of oligopoly competition where agents can select between different behavioral rules to make decisions on productions. We formalize the model as a general class of evolutionary oligopoly games and then we consider an example with two specific rules, namely Local Monopolistic Approximation and Gradient dynamics. We provide several results on the global dynamic properties of the model, showing that in some cases the attractor of the system may belong to an invariant plane where only one behavioral rule is adopted (monomorphic state). The attractors on the invariant planes can be either strong attractors or weak attractors. However, we also explain why the system can be in a state of Evolutionary Stable Heterogeneity, where it is more profitable for the agents to employ both heuristics in the long term (polymorphic state).

  2. Evolutionary foundations for cancer biology.

    Science.gov (United States)

    Aktipis, C Athena; Nesse, Randolph M

    2013-01-01

    New applications of evolutionary biology are transforming our understanding of cancer. The articles in this special issue provide many specific examples, such as microorganisms inducing cancers, the significance of within-tumor heterogeneity, and the possibility that lower dose chemotherapy may sometimes promote longer survival. Underlying these specific advances is a large-scale transformation, as cancer research incorporates evolutionary methods into its toolkit, and asks new evolutionary questions about why we are vulnerable to cancer. Evolution explains why cancer exists at all, how neoplasms grow, why cancer is remarkably rare, and why it occurs despite powerful cancer suppression mechanisms. Cancer exists because of somatic selection; mutations in somatic cells result in some dividing faster than others, in some cases generating neoplasms. Neoplasms grow, or do not, in complex cellular ecosystems. Cancer is relatively rare because of natural selection; our genomes were derived disproportionally from individuals with effective mechanisms for suppressing cancer. Cancer occurs nonetheless for the same six evolutionary reasons that explain why we remain vulnerable to other diseases. These four principles-cancers evolve by somatic selection, neoplasms grow in complex ecosystems, natural selection has shaped powerful cancer defenses, and the limitations of those defenses have evolutionary explanations-provide a foundation for understanding, preventing, and treating cancer.

  3. Evolutionary genomics of environmental pollution.

    Science.gov (United States)

    Whitehead, Andrew

    2014-01-01

    Chemical toxins have been a persistent source of evolutionary challenges throughout the history of life, and deep within the genomic storehouse of evolutionary history lay ancient adaptations to diverse chemical poisons. However, the rate of change of contemporary environments mediated by human-introduced pollutants is rapidly screening this storehouse and severely testing the adaptive potential of many species. In this chapter, we briefly review the deep history of evolutionary adaptation to environmental toxins, and then proceed to describe the attributes of stressors and populations that may facilitate contemporary adaptation to pollutants introduced by humans. We highlight that phenotypes derived to enable persistence in polluted habitats may be multi-dimensional, requiring global genome-scale tools and approaches to uncover their mechanistic basis, and include examples of recent progress in the field. The modern tools of genomics offer promise for discovering how pollutants interact with genomes on physiological timescales, and also for discovering what genomic attributes of populations may enable resistance to pollutants over evolutionary timescales. Through integration of these sophisticated genomics tools and approaches with an understanding of the deep historical forces that shaped current populations, a more mature understanding of the mechanistic basis of contemporary ecological-evolutionary dynamics should emerge.

  4. Evolutionary analyses of non-genealogical bonds produced by introgressive descent.

    Science.gov (United States)

    Bapteste, Eric; Lopez, Philippe; Bouchard, Frédéric; Baquero, Fernando; McInerney, James O; Burian, Richard M

    2012-11-06

    All evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. However, many other kinds of processes contribute to evolutionary diversity. In vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. In what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated within these host structures. Thus, introgressive descent generates a variety of evolutionary units and leaves recognizable patterns in resemblance networks. We characterize six kinds of evolutionary units, of which five involve mosaic lineages generated by introgressive descent. To facilitate detection of these units in resemblance networks, we introduce terminology based on two notions, P3s (subgraphs of three nodes: A, B, and C) and mosaic P3s, and suggest an apparatus for systematic detection of introgressive descent. Mosaic P3s correspond to a distinct type of evolutionary bond that is orthogonal to the bonds of kinship and genealogy usually examined by evolutionary biologists. We argue that recognition of these evolutionary bonds stimulates radical rethinking of key questions in evolutionary biology (e.g., the relations among evolutionary players in very early phases of evolutionary history, the origin and emergence of novelties, and the production of new lineages). This line of research will expand the study of biological complexity beyond the usual genealogical bonds, revealing additional sources of biodiversity. It provides an important step to a more realistic pluralist treatment of evolutionary complexity.

  5. Strong-coupling approximations

    International Nuclear Information System (INIS)

    Abbott, R.B.

    1984-03-01

    Standard path-integral techniques such as instanton calculations give good answers for weak-coupling problems, but become unreliable for strong-coupling. Here we consider a method of replacing the original potential by a suitably chosen harmonic oscillator potential. Physically this is motivated by the fact that potential barriers below the level of the ground-state energy of a quantum-mechanical system have little effect. Numerically, results are good, both for quantum-mechanical problems and for massive phi 4 field theory in 1 + 1 dimensions. 9 references, 6 figures

  6. Strong interaction and QFD

    International Nuclear Information System (INIS)

    Ebata, T.

    1981-01-01

    With an assumed weak multiplet structure for bosonic hadrons, which is consistent with the ΔI = 1/2 rule, it is shown that the strong interaction effective hamiltonian is compatible with the weak SU(2) x U(1) gauge transformation. Especially the rho-meson transforms as a triplet under SU(2)sub(w), and this is the origin of the rho-photon analogy. It is also shown that the existence of the non-vanishing Cabibbo angle is a necessary condition for the absence of the exotic hadrons. (orig.)

  7. Strong Coupling Holography

    CERN Document Server

    Dvali, Gia

    2009-01-01

    We show that whenever a 4-dimensional theory with N particle species emerges as a consistent low energy description of a 3-brane embedded in an asymptotically-flat (4+d)-dimensional space, the holographic scale of high-dimensional gravity sets the strong coupling scale of the 4D theory. This connection persists in the limit in which gravity can be consistently decoupled. We demonstrate this effect for orbifold planes, as well as for the solitonic branes and string theoretic D-branes. In all cases the emergence of a 4D strong coupling scale from bulk holography is a persistent phenomenon. The effect turns out to be insensitive even to such extreme deformations of the brane action that seemingly shield 4D theory from the bulk gravity effects. A well understood example of such deformation is given by large 4D Einstein term in the 3-brane action, which is known to suppress the strength of 5D gravity at short distances and change the 5D Newton's law into the four-dimensional one. Nevertheless, we observe that the ...

  8. Yin and yang surfaces: an evolutionary perspective.

    Science.gov (United States)

    Legge, David

    2014-12-01

    A search of the Chinese medicine literature reveals several conflicting explanations of the division of the body into yin and yang surfaces. This paper attempts to clarify this basic concept and reconcile the differing descriptions of it through an exploration of material from other disciplines. A remarkable similarity exists between the surfaces on the human body that are defined by the pathways of the yin and yang meridians and those that have evolved from the ventral and the dorsal aspects of early vertebrate structure. Many of the evolutionary changes described have parallels in our embryological development and are evident in the underlying anatomy of our limbs. The degree of convergence between the two descriptions strongly supports the definition of the yin and yang surfaces as those traversed by the yin and yang meridians. It also goes a long way towards reconciling the conflicting definitions found in the literature. Finding a solution to this question of yin and yang surfaces that is based on anatomy and evolutionary theories has several advantages. It can throw light on differences in the clinical effects of points on the yin and yang meridians and enable the identification of anomalies in the pathways of the main meridian network. Copyright © 2014. Published by Elsevier B.V.

  9. Evolutionary diversification in stickleback affects ecosystem functioning.

    Science.gov (United States)

    Harmon, Luke J; Matthews, Blake; Des Roches, Simone; Chase, Jonathan M; Shurin, Jonathan B; Schluter, Dolph

    2009-04-30

    Explaining the ecological causes of evolutionary diversification is a major focus of biology, but surprisingly little has been said about the effects of evolutionary diversification on ecosystems. The number of species in an ecosystem and their traits are key predictors of many ecosystem-level processes, such as rates of productivity, biomass sequestration and decomposition. Here we demonstrate short-term ecosystem-level effects of adaptive radiation in the threespine stickleback (Gasterosteus aculeatus) over the past 10,000 years. These fish have undergone recent parallel diversification in several lakes in coastal British Columbia, resulting in the formation of two specialized species (benthic and limnetic) from a generalist ancestor. Using a mesocosm experiment, we demonstrate that this diversification has strong effects on ecosystems, affecting prey community structure, total primary production, and the nature of dissolved organic materials that regulate the spectral properties of light transmission in the system. However, these ecosystem effects do not simply increase in their relative strength with increasing specialization and species richness; instead, they reflect the complex and indirect consequences of ecosystem engineering by sticklebacks. It is well known that ecological factors influence adaptive radiation. We demonstrate that adaptive radiation, even over short timescales, can have profound effects on ecosystems.

  10. The evolutionary psychology of hunger.

    Science.gov (United States)

    Al-Shawaf, Laith

    2016-10-01

    An evolutionary psychological perspective suggests that emotions can be understood as coordinating mechanisms whose job is to regulate various psychological and physiological programs in the service of solving an adaptive problem. This paper suggests that it may also be fruitful to approach hunger from this coordinating mechanism perspective. To this end, I put forward an evolutionary task analysis of hunger, generating novel a priori hypotheses about the coordinating effects of hunger on psychological processes such as perception, attention, categorization, and memory. This approach appears empirically fruitful in that it yields a bounty of testable new hypotheses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Diversity-Guided Evolutionary Algorithms

    DEFF Research Database (Denmark)

    Ursem, Rasmus Kjær

    2002-01-01

    Population diversity is undoubtably a key issue in the performance of evolutionary algorithms. A common hypothesis is that high diversity is important to avoid premature convergence and to escape local optima. Various diversity measures have been used to analyze algorithms, but so far few...... algorithms have used a measure to guide the search. The diversity-guided evolutionary algorithm (DGEA) uses the wellknown distance-to-average-point measure to alternate between phases of exploration (mutation) and phases of exploitation (recombination and selection). The DGEA showed remarkable results...

  12. Prey preference follows phylogeny: evolutionary dietary patterns within the marine gastropod group Cladobranchia (Gastropoda: Heterobranchia: Nudibranchia).

    Science.gov (United States)

    Goodheart, Jessica A; Bazinet, Adam L; Valdés, Ángel; Collins, Allen G; Cummings, Michael P

    2017-10-26

    The impact of predator-prey interactions on the evolution of many marine invertebrates is poorly understood. Since barriers to genetic exchange are less obvious in the marine realm than in terrestrial or freshwater systems, non-allopatric divergence may play a fundamental role in the generation of biodiversity. In this context, shifts between major prey types could constitute important factors explaining the biodiversity of marine taxa, particularly in groups with highly specialized diets. However, the scarcity of marine specialized consumers for which reliable phylogenies exist hampers attempts to test the role of trophic specialization in evolution. In this study, RNA-Seq data is used to produce a phylogeny of Cladobranchia, a group of marine invertebrates that feed on a diverse array of prey taxa but mostly specialize on cnidarians. The broad range of prey type preferences allegedly present in two major groups within Cladobranchia suggest that prey type shifts are relatively common over evolutionary timescales. In the present study, we generated a well-supported phylogeny of the major lineages within Cladobranchia using RNA-Seq data, and used ancestral state reconstruction analyses to better understand the evolution of prey preference. These analyses answered several fundamental questions regarding the evolutionary relationships within Cladobranchia, including support for a clade of species from Arminidae as sister to Tritoniidae (which both preferentially prey on Octocorallia). Ancestral state reconstruction analyses supported a cladobranchian ancestor with a preference for Hydrozoa and show that the few transitions identified only occur from lineages that prey on Hydrozoa to those that feed on other types of prey. There is strong phylogenetic correlation with prey preference within Cladobranchia, suggesting that prey type specialization within this group has inertia. Shifts between different types of prey have occurred rarely throughout the evolution of

  13. Climate constrains the evolutionary history and biodiversity of crocodylians.

    Science.gov (United States)

    Mannion, Philip D; Benson, Roger B J; Carrano, Matthew T; Tennant, Jonathan P; Judd, Jack; Butler, Richard J

    2015-09-24

    The fossil record of crocodylians and their relatives (pseudosuchians) reveals a rich evolutionary history, prompting questions about causes of long-term decline to their present-day low biodiversity. We analyse climatic drivers of subsampled pseudosuchian biodiversity over their 250 million year history, using a comprehensive new data set. Biodiversity and environmental changes correlate strongly, with long-term decline of terrestrial taxa driven by decreasing temperatures in northern temperate regions, and biodiversity decreases at lower latitudes matching patterns of increasing aridification. However, there is no relationship between temperature and biodiversity for marine pseudosuchians, with sea-level change and post-extinction opportunism demonstrated to be more important drivers. A 'modern-type' latitudinal biodiversity gradient might have existed throughout pseudosuchian history, and range expansion towards the poles occurred during warm intervals. Although their fossil record suggests that current global warming might promote long-term increases in crocodylian biodiversity and geographic range, the 'balancing forces' of anthropogenic environmental degradation complicate future predictions.

  14. On the evolutionary origins of differences in sexual preferences

    Directory of Open Access Journals (Sweden)

    Daniil eRyabko

    2015-05-01

    Full Text Available A novel general explanation of the evolutionary process leading to the appearance of differences insexual preferences is proposed. The explanation is fully general: it is not specific to any particular type of sexual preferences, nor to any species orpopulation. It shows how different sexual preferences can appear in any large group-living population in which sexual selection is sufficiently strong in each sex. The main idea is that the lack of interest towards a member of the opposite sex may be interpreted as a signal of popularity, and thus a sign of reproductive success. It is then boosted by the Fisher runaway process, resulting in a generalized trait~--- lack of interest towards the opposite sex. This trait develops far beyond the point when it gives a reproductive disadvantage, resulting in well-pronounced different sexual preferences. This hypothesis is placed into the context of other works on different sexual preferences in animals; supporting evidence from the literature is reviewed and additional research needed to confirm or refute the hypothesis in any given species is outlined.

  15. Evolutionary contribution to coexistence of competitors in microbial food webs.

    Science.gov (United States)

    Hiltunen, Teppo; Kaitala, Veijo; Laakso, Jouni; Becks, Lutz

    2017-10-11

    The theory of species coexistence is a key concept in ecology that has received much attention. The role of rapid evolution for determining species coexistence is still poorly understood although evolutionary change on ecological time-scales has the potential to change almost any ecological process. The influence of evolution on coexistence can be especially pronounced in microbial communities where organisms often have large population sizes and short generation times. Previous work on coexistence has assumed that traits involved in resource use and species interactions are constant or change very slowly in terms of ecological time-scales. However, recent work suggests that these traits can evolve rapidly. Nevertheless, the importance of rapid evolution to coexistence has not been tested experimentally. Here, we show how rapid evolution alters the frequency of two bacterial competitors over time when grown together with specialist consumers (bacteriophages), a generalist consumer (protozoan) and all in combination. We find that consumers facilitate coexistence in a manner consistent with classic ecological theory. However, through disentangling the relative contributions of ecology (changes in consumer abundance) and evolution (changes in traits mediating species interactions) on the frequency of the two competitors over time, we find differences between the consumer types and combinations. Overall, our results indicate that the influence of evolution on species coexistence strongly depends on the traits and species interactions considered. © 2017 The Author(s).

  16. LIGO: The strong belief

    CERN Multimedia

    Antonella Del Rosso

    2016-01-01

    Twenty years of designing, building and testing a number of innovative technologies, with the strong belief that the endeavour would lead to a historic breakthrough. The Bulletin publishes an abstract of the Courier’s interview with Barry Barish, one of the founding fathers of LIGO.   The plots show the signals of gravitational waves detected by the twin LIGO observatories at Livingston, Louisiana, and Hanford, Washington. (Image: Caltech/MIT/LIGO Lab) On 11 February, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo collaborations published a historic paper in which they showed a gravitational signal emitted by the merger of two black holes. These results come after 20 years of hard work by a large collaboration of scientists operating the two LIGO observatories in the US. Barry Barish, Linde Professor of Physics, Emeritus at the California Institute of Technology and former Director of the Global Design Effort for the Internat...

  17. Evolutionary paths of streptococcal and staphylococcal superantigens

    Directory of Open Access Journals (Sweden)

    Okumura Kayo

    2012-08-01

    Full Text Available Abstract Background Streptococcus pyogenes (GAS harbors several superantigens (SAgs in the prophage region of its genome, although speG and smez are not located in this region. The diversity of SAgs is thought to arise during horizontal transfer, but their evolutionary pathways have not yet been determined. We recently completed sequencing the entire genome of S. dysgalactiae subsp. equisimilis (SDSE, the closest relative of GAS. Although speG is the only SAg gene of SDSE, speG was present in only 50% of clinical SDSE strains and smez in none. In this study, we analyzed the evolutionary paths of streptococcal and staphylococcal SAgs. Results We compared the sequences of the 12–60 kb speG regions of nine SDSE strains, five speG+ and four speG–. We found that the synteny of this region was highly conserved, whether or not the speG gene was present. Synteny analyses based on genome-wide comparisons of GAS and SDSE indicated that speG is the direct descendant of a common ancestor of streptococcal SAgs, whereas smez was deleted from SDSE after SDSE and GAS split from a common ancestor. Cumulative nucleotide skew analysis of SDSE genomes suggested that speG was located outside segments of steeper slopes than the stable region in the genome, whereas the region flanking smez was unstable, as expected from the results of GAS. We also detected a previously undescribed staphylococcal SAg gene, selW, and a staphylococcal SAg -like gene, ssl, in the core genomes of all Staphylococcus aureus strains sequenced. Amino acid substitution analyses, based on dN/dS window analysis of the products encoded by speG, selW and ssl suggested that all three genes have been subjected to strong positive selection. Evolutionary analysis based on the Bayesian Markov chain Monte Carlo method showed that each clade included at least one direct descendant. Conclusions Our findings reveal a plausible model for the comprehensive evolutionary pathway of streptococcal and

  18. Patterns of evolutionary constraints on genes in humans

    Directory of Open Access Journals (Sweden)

    Lopez-Bigas Nuria

    2008-10-01

    Full Text Available Abstract Background Different regions in a genome evolve at different rates depending on structural and functional constraints. Some genomic regions are highly conserved during metazoan evolution, while other regions may evolve rapidly, either in all species or in a lineage-specific manner. A strong or even moderate change in constraints in functional regions, for example in coding regions, can have significant evolutionary consequences. Results Here we discuss a novel framework, 'BaseDiver', to classify groups of genes in humans based on the patterns of evolutionary constraints on polymorphic positions in their coding regions. Comparing the nucleotide-level divergence among mammals with the extent of deviation from the ancestral base in the human lineage, we identify patterns of evolutionary pressure on nonsynonymous base-positions in groups of genes belonging to the same functional category. Focussing on groups of genes in functional categories, we find that transcription factors contain a significant excess of nonsynonymous base-positions that are conserved in other mammals but changed in human, while immunity related genes harbour mutations at base-positions that evolve rapidly in all mammals including humans due to strong preference for advantageous alleles. Genes involved in olfaction also evolve rapidly in all mammals, and in humans this appears to be due to weak negative selection. Conclusion While recent studies have identified genes under positive selection in humans, our approach identifies evolutionary constraints on Gene Ontology groups identifying changes in humans relative to some of the other mammals.

  19. Investigating evolutionary conservation of dendritic cell subset identity and functions

    Directory of Open Access Journals (Sweden)

    Thien-Phong eVu Manh

    2015-06-01

    Full Text Available Dendritic cells (DC were initially defined as mononuclear phagocytes with a dendritic morphology and an exquisite efficiency for naïve T cell activation. DC encompass several subsets initially identified by their expression of specific cell surface molecules and later shown to excel in distinct functions and to develop under the instruction of different transcription factors or cytokines. Very few cell surface molecules are expressed in a specific manner on any immune cell type. Hence, to identify cell types, the sole use of a small number of cell surface markers in classical flow cytometry can be deceiving. Moreover, the markers currently used to define mononuclear phagocyte subsets vary depending on the tissue and animal species studied and even between laboratories. This has led to confusion in the definition of DC subset identity and in their attribution of specific functions. There is a strong need to identify a rigorous and consensus way to define mononuclear phagocyte subsets, with precise guidelines potentially applicable throughout tissues and species. We will discuss the advantages, drawbacks and complementarities of different methodologies: cell surface phenotyping, ontogeny, functional characterization and molecular profiling. We will advocate that gene expression profiling is a very rigorous, largely unbiased and accessible method to define the identity of mononuclear phagocyte subsets, which strengthens and refines surface phenotyping. It is uniquely powerful to yield new, experimentally testable, hypotheses on the ontogeny or functions of mononuclear phagocyte subsets, their molecular regulation and their evolutionary conservation. We propose defining cell populations based on a combination of cell surface phenotyping, expression analysis of hallmark genes and robust functional assays, in order to reach a consensus and integrate faster the huge but scattered knowledge accumulated by different laboratories on different cell types

  20. Investigating Evolutionary Conservation of Dendritic Cell Subset Identity and Functions.

    Science.gov (United States)

    Vu Manh, Thien-Phong; Bertho, Nicolas; Hosmalin, Anne; Schwartz-Cornil, Isabelle; Dalod, Marc

    2015-01-01

    Dendritic cells (DCs) were initially defined as mononuclear phagocytes with a dendritic morphology and an exquisite efficiency for naïve T-cell activation. DC encompass several subsets initially identified by their expression of specific cell surface molecules and later shown to excel in distinct functions and to develop under the instruction of different transcription factors or cytokines. Very few cell surface molecules are expressed in a specific manner on any immune cell type. Hence, to identify cell types, the sole use of a small number of cell surface markers in classical flow cytometry can be deceiving. Moreover, the markers currently used to define mononuclear phagocyte subsets vary depending on the tissue and animal species studied and even between laboratories. This has led to confusion in the definition of DC subset identity and in their attribution of specific functions. There is a strong need to identify a rigorous and consensus way to define mononuclear phagocyte subsets, with precise guidelines potentially applicable throughout tissues and species. We will discuss the advantages, drawbacks, and complementarities of different methodologies: cell surface phenotyping, ontogeny, functional characterization, and molecular profiling. We will advocate that gene expression profiling is a very rigorous, largely unbiased and accessible method to define the identity of mononuclear phagocyte subsets, which strengthens and refines surface phenotyping. It is uniquely powerful to yield new, experimentally testable, hypotheses on the ontogeny or functions of mononuclear phagocyte subsets, their molecular regulation, and their evolutionary conservation. We propose defining cell populations based on a combination of cell surface phenotyping, expression analysis of hallmark genes, and robust functional assays, in order to reach a consensus and integrate faster the huge but scattered knowledge accumulated by different laboratories on different cell types, organs, and

  1. Theoretical Approaches in Evolutionary Ecology: Environmental Feedback as a Unifying Perspective.

    Science.gov (United States)

    Lion, Sébastien

    2018-01-01

    Evolutionary biology and ecology have a strong theoretical underpinning, and this has fostered a variety of modeling approaches. A major challenge of this theoretical work has been to unravel the tangled feedback loop between ecology and evolution. This has prompted the development of two main classes of models. While quantitative genetics models jointly consider the ecological and evolutionary dynamics of a focal population, a separation of timescales between ecology and evolution is assumed by evolutionary game theory, adaptive dynamics, and inclusive fitness theory. As a result, theoretical evolutionary ecology tends to be divided among different schools of thought, with different toolboxes and motivations. My aim in this synthesis is to highlight the connections between these different approaches and clarify the current state of theory in evolutionary ecology. Central to this approach is to make explicit the dependence on environmental dynamics of the population and evolutionary dynamics, thereby materializing the eco-evolutionary feedback loop. This perspective sheds light on the interplay between environmental feedback and the timescales of ecological and evolutionary processes. I conclude by discussing some potential extensions and challenges to our current theoretical understanding of eco-evolutionary dynamics.

  2. Evolutionary origin of the turtle skull.

    Science.gov (United States)

    Bever, G S; Lyson, Tyler R; Field, Daniel J; Bhullar, Bhart-Anjan S

    2015-09-10

    Transitional fossils informing the origin of turtles are among the most sought-after discoveries in palaeontology. Despite strong genomic evidence indicating that turtles evolved from within the diapsid radiation (which includes all other living reptiles), evidence of the inferred transformation between an ancestral turtle with an open, diapsid skull to the closed, anapsid condition of modern turtles remains elusive. Here we use high-resolution computed tomography and a novel character/taxon matrix to study the skull of Eunotosaurus africanus, a 260-million-year-old fossil reptile from the Karoo Basin of South Africa, whose distinctive postcranial skeleton shares many unique features with the shelled body plan of turtles. Scepticism regarding the status of Eunotosaurus as the earliest stem turtle arises from the possibility that these shell-related features are the products of evolutionary convergence. Our phylogenetic analyses indicate strong cranial support for Eunotosaurus as a critical transitional form in turtle evolution, thus fortifying a 40-million-year extension to the turtle stem and moving the ecological context of its origin back onto land. Furthermore, we find unexpected evidence that Eunotosaurus is a diapsid reptile in the process of becoming secondarily anapsid. This is important because categorizing the skull based on the number of openings in the complex of dermal bone covering the adductor chamber has long held sway in amniote systematics, and still represents a common organizational scheme for teaching the evolutionary history of the group. These discoveries allow us to articulate a detailed and testable hypothesis of fenestral closure along the turtle stem. Our results suggest that Eunotosaurus represents a crucially important link in a chain that will eventually lead to consilience in reptile systematics, paving the way for synthetic studies of amniote evolution and development.

  3. Evolutionary genetics: the Drosophila model

    Indian Academy of Sciences (India)

    Unknown

    ral selection is provided by studies—sometimes characterized as evolutionary ecology—that attempt to understand how and why particular fitness functions are defined on the distribution of phenotypes in a population by its ecology. Studying how the interaction between phenotype and environment results in a fitness ...

  4. Conceptual foundations of evolutionary thought

    Indian Academy of Sciences (India)

    2017-07-04

    Jul 4, 2017 ... Home; Journals; Journal of Genetics; Volume 96; Issue 3. Conceptual foundations of evolutionary thought. K. P. MOHANAN. Perspectives Volume 96 Issue 3 July 2017 pp 401-412. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/jgen/096/03/0401-0412. Abstract ...

  5. Evolutionary robotics–A review

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... In evolutionary robotics, a suitable robot control system is developed automatically through evolution due to the interactions between the robot and its environment. It is a complicated task, as the robot and the environment constitute a highly dynamical system. Several methods have been tried by various ...

  6. Haldane and modern evolutionary genetics

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 96; Issue 5. Haldane and modern evolutionary genetics. BRIAN CHARLESWORTH. HALDANE AT 125 Volume 96 Issue 5 November 2017 pp 773-782. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/jgen/096/05/0773-0782. Keywords.

  7. Scalable Computing for Evolutionary Genomics

    NARCIS (Netherlands)

    Prins, J.C.P.; Belhachemi, D.; Möller, S.; Smant, G.

    2012-01-01

    Genomic data analysis in evolutionary biology is becoming so computationally intensive that analysis of multiple hypotheses and scenarios takes too long on a single desktop computer. In this chapter, we discuss techniques for scaling computations through parallelization of calculations, after giving

  8. Evolutionary Biology Research in India

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 10. Evolutionary Biology Research in India. Information and Announcements Volume 5 Issue 10 October 2000 pp 102-104. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/005/10/0102-0104 ...

  9. Cryptic eco-evolutionary dynamics.

    Science.gov (United States)

    Kinnison, Michael T; Hairston, Nelson G; Hendry, Andrew P

    2015-12-01

    Natural systems harbor complex interactions that are fundamental parts of ecology and evolution. These interactions challenge our inclinations and training to seek the simplest explanations of patterns in nature. Not least is the likelihood that some complex processes might be missed when their patterns look similar to predictions for simpler mechanisms. Along these lines, theory and empirical evidence increasingly suggest that environmental, ecological, phenotypic, and genetic processes can be tightly intertwined, resulting in complex and sometimes surprising eco-evolutionary dynamics. The goal of this review is to temper inclinations to unquestioningly seek the simplest explanations in ecology and evolution, by recognizing that some eco-evolutionary outcomes may appear very similar to purely ecological, purely evolutionary, or even null expectations, and thus be cryptic. We provide theoretical and empirical evidence for observational biases and mechanisms that might operate among the various links in eco-evolutionary feedbacks to produce cryptic patterns. Recognition that cryptic dynamics can be associated with outcomes like stability, resilience, recovery, or coexistence in a dynamically changing world provides added impetus for finding ways to study them. © 2015 New York Academy of Sciences.

  10. Darwinian foundations for evolutionary economics

    NARCIS (Netherlands)

    Stoelhorst, J.W.

    2008-01-01

    This paper engages with the methodological debate on the contribution of Darwinism to Veblen's (1898) evolutionary research program for economics. I argue that ontological continuity, generalized Darwinism, and multi-level selection are necessary building blocks for an explanatory framework that can

  11. Evolutionary Psychology and Intelligence Research

    Science.gov (United States)

    Kanazawa, Satoshi

    2010-01-01

    This article seeks to unify two subfields of psychology that have hitherto stood separately: evolutionary psychology and intelligence research/differential psychology. I suggest that general intelligence may simultaneously be an evolved adaptation and an individual-difference variable. Tooby and Cosmides's (1990a) notion of random quantitative…

  12. Diversity-Guided Evolutionary Algorithms

    DEFF Research Database (Denmark)

    Ursem, Rasmus Kjær

    2002-01-01

    Population diversity is undoubtably a key issue in the performance of evolutionary algorithms. A common hypothesis is that high diversity is important to avoid premature convergence and to escape local optima. Various diversity measures have been used to analyze algorithms, but so far few algorit...

  13. Testing evolutionary theories of menopause.

    Science.gov (United States)

    Shanley, Daryl P; Sear, Rebecca; Mace, Ruth; Kirkwood, Thomas B L

    2007-12-07

    Why do women cease fertility rather abruptly through menopause at an age well before generalized senescence renders child rearing biologically impossible? The two main evolutionary hypotheses are that menopause serves either (i) to protect mothers from rising age-specific maternal mortality risks, thereby protecting their highly dependent younger children from death if the mother dies or (ii) to provide post-reproductive grandmothers who enhance their inclusive fitness by helping to care and provide for their daughters' children. Recent theoretical work indicates that both factors together are necessary if menopause is to provide an evolutionary advantage. However, these ideas need to be tested using detailed data from actual human life histories lived under reasonably 'natural' conditions; for obvious reasons, such data are extremely scarce. We here describe a study based on a remarkably complete dataset from The Gambia. The data provided quantitative estimates for key parameters for the theoretical model, which were then used to assess the actual effects on fitness. Empirically based numerical analysis of this nature is essential if the enigma of menopause is to be explained satisfactorily in evolutionary terms. Our results point to the distinctive (and perhaps unique) role of menopause in human evolution and provide important support for the hypothesized evolutionary significance of grandmothers.

  14. Defining fitness in evolutionary models

    Indian Academy of Sciences (India)

    2008-12-23

    Dec 23, 2008 ... The analysis of evolutionary models requires an appropriate definition for fitness. ..... of dimorphism for dormancy in plants (Cohen 1966). .... yses have assumed nonoverlapping generations (i.e. no age- structure). The solution to defining fitness when the environ- ment is spatially variable and there is a ...

  15. Evolutionary dynamics of mammalian karyotypes

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Redi

    2012-12-01

    Full Text Available This special volume of Cytogenetic and Genome Research (edited by Roscoe Stanyon, University of Florence and Alexander Graphodatsky, Siberian division of the Russian Academy of Sciences is dedicated to the fascinating long search of the forces behind the evolutionary dynamics of mammalian karyotypes, revealed after the hypotonic miracle of the 1950s....

  16. Euryhalinity in an evolutionary context

    Science.gov (United States)

    Schultz, Eric T.; McCormick, Stephen D.; McCormick, Stephen D.; Farrell, Anthony Peter; Brauner, Colin J.

    2013-01-01

    This chapter focuses on the evolutionary importance and taxonomic distribution of euryhalinity. Euryhalinity refers to broad halotolerance and broad halohabitat distribution. Salinity exposure experiments have demonstrated that species vary tenfold in their range of tolerable salinity levels, primarily because of differences in upper limits. Halotolerance breadth varies with the species’ evolutionary history, as represented by its ordinal classification, and with the species’ halohabitat. Freshwater and seawater species tolerate brackish water; their empirically-determined fundamental haloniche is broader than their realized haloniche, as revealed by the halohabitats they occupy. With respect to halohabitat distribution, a minority of species (basal actinopterygian fishes, is largely absent from orders arising from intermediate nodes, and reappears in the most derived taxa. There is pronounced family-level variability in the tendency to be halohabitat-euryhaline, which may have arisen during a burst of diversification following the Cretaceous-Palaeogene extinction. Low prevalence notwithstanding, euryhaline species are potent sources of evolutionary diversity. Euryhalinity is regarded as a key innovation trait whose evolution enables exploitation of new adaptive zone, triggering cladogenesis. We review phylogenetically-informed studies that demonstrate freshwater species diversifying from euryhaline ancestors through processes such as landlocking. These studies indicate that some euryhaline taxa are particularly susceptible to changes in halohabitat and subsequent diversification, and some geographic regions have been hotspots for transitions to freshwater. Comparative studies on mechanisms among multiple taxa and at multiple levels of biological integration are needed to clarify evolutionary pathways to, and from, euryhalinity.

  17. Ernst Mayr and Evolutionary Biology

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 7. Polemics and Synthesis: Ernst Mayr and Evolutionary Biology. Renee M Borges. General Article Volume 10 Issue 7 July 2005 pp 21-33. Fulltext. Click here to view fulltext PDF. Permanent link:

  18. Evolutionary Biology Research in India

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 10. Evolutionary Biology Research in India. Information and Announcements Volume 5 Issue 10 October 2000 pp 102-104. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/005/10/0102-0104 ...

  19. Evolutionary robotics – A review

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    to solve this problem. This paper provides a survey on some of these important studies carried out in the recent past. Keywords. Evolutionary robotics; genetic ... neural network (NN) (Kosko 1994), to study the interaction between evolution and learning. .... After GA-based learning of the neural controller, the navigation.

  20. John Strong (1941 - 2006)

    CERN Multimedia

    Wickens, F

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on Monday 31st July, a few days before his 65th birthday John started his career working with a group from Westfield College, under the leadership of Ted Bellamy. He obtained his PhD and spent the early part of his career on experiments at Rutherford Appleton Laboratory (RAL), but after the early 1970s his research was focussed on experiments in CERN. Over the years he made a number of notable contributions to experiments in CERN: The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras to record the sparks in the spark chambers; He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems; He was responsible for the second level trigger system for the ALEPH detector and spent five years leading a team that designed and built the system, which ran for twelve years with only minor interventions. Following ALEPH he tur...

  1. Stirring Strongly Coupled Plasma

    CERN Document Server

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  2. Strong-interaction nonuniversality

    International Nuclear Information System (INIS)

    Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.

    1989-01-01

    The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements

  3. Evolutionary Computing Methods for Spectral Retrieval

    Science.gov (United States)

    Terrile, Richard; Fink, Wolfgang; Huntsberger, Terrance; Lee, Seugwon; Tisdale, Edwin; VonAllmen, Paul; Tinetti, Geivanna

    2009-01-01

    A methodology for processing spectral images to retrieve information on underlying physical, chemical, and/or biological phenomena is based on evolutionary and related computational methods implemented in software. In a typical case, the solution (the information that one seeks to retrieve) consists of parameters of a mathematical model that represents one or more of the phenomena of interest. The methodology was developed for the initial purpose of retrieving the desired information from spectral image data acquired by remote-sensing instruments aimed at planets (including the Earth). Examples of information desired in such applications include trace gas concentrations, temperature profiles, surface types, day/night fractions, cloud/aerosol fractions, seasons, and viewing angles. The methodology is also potentially useful for retrieving information on chemical and/or biological hazards in terrestrial settings. In this methodology, one utilizes an iterative process that minimizes a fitness function indicative of the degree of dissimilarity between observed and synthetic spectral and angular data. The evolutionary computing methods that lie at the heart of this process yield a population of solutions (sets of the desired parameters) within an accuracy represented by a fitness-function value specified by the user. The evolutionary computing methods (ECM) used in this methodology are Genetic Algorithms and Simulated Annealing, both of which are well-established optimization techniques and have also been described in previous NASA Tech Briefs articles. These are embedded in a conceptual framework, represented in the architecture of the implementing software, that enables automatic retrieval of spectral and angular data and analysis of the retrieved solutions for uniqueness.

  4. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    make use of 'small' electrons packed to the highest possible density. These are by definition 'strongly correlated'. For example: good photovoltaics must be efficient optical absorbers, which means that photons will generate tightly bound electron-hole pairs (excitons) that must then be ionised at a heterointerface and transported to contacts; efficient solid state refrigeration depends on substantial entropy changes in a unit cell, with large local electrical or magnetic moments; efficient lighting is in a real sense the inverse of photovoltaics; the limit of an efficient battery is a supercapacitor employing mixed valent ions; fuel cells and solar to fuel conversion require us to understand electrochemistry on the scale of a single atom; and we already know that the only prospect for effective high temperature superconductivity involves strongly correlated materials. Even novel IT technologies are now seen to have value not just for novel function but also for efficiency. While strongly correlated electron systems continue to excite researchers and the public alike due to the fundamental science issues involved, it seems increasingly likely that support for the science will be leveraged by its impact on energy and sustainability. Strongly correlated electron systems contents Strongly correlated electron systemsSiddharth S Saxena and P B Littlewood Magnetism, f-electron localization and superconductivity in 122-type heavy-fermion metalsF Steglich, J Arndt, O Stockert, S Friedemann, M Brando, C Klingner, C Krellner, C Geibel, S Wirth, S Kirchner and Q Si High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopyN L Wang, W Z Hu, Z G Chen, R H Yuan, G Li, G F Chen and T Xiang Structural investigations on YbRh2Si2: from the atomic to the macroscopic length scaleS Wirth, S Ernst, R Cardoso-Gil, H Borrmann, S Seiro, C Krellner, C Geibel, S Kirchner, U Burkhardt, Y Grin and F Steglich Confinement of chiral magnetic

  5. Towards a mechanistic foundation of evolutionary theory.

    Science.gov (United States)

    Doebeli, Michael; Ispolatov, Yaroslav; Simon, Burt

    2017-02-15

    Most evolutionary thinking is based on the notion of fitness and related ideas such as fitness landscapes and evolutionary optima. Nevertheless, it is often unclear what fitness actually is, and its meaning often depends on the context. Here we argue that fitness should not be a basal ingredient in verbal or mathematical descriptions of evolution. Instead, we propose that evolutionary birth-death processes, in which individuals give birth and die at ever-changing rates, should be the basis of evolutionary theory, because such processes capture the fundamental events that generate evolutionary dynamics. In evolutionary birth-death processes, fitness is at best a derived quantity, and owing to the potential complexity of such processes, there is no guarantee that there is a simple scalar, such as fitness, that would describe long-term evolutionary outcomes. We discuss how evolutionary birth-death processes can provide useful perspectives on a number of central issues in evolution.

  6. Evolutionary biology of bacterial and fungal pathogens

    National Research Council Canada - National Science Library

    Cassell, Gail H; Gutierrez-Fuentes, Jose A; Barquero, Fernando; Nombela, Cesar

    2008-01-01

    ... and Evolutionary Dynamics of Pathogens * 21 Keith A. Crandall and Marcos Pérez-Losada II. Evolutionary Genetics of Microbial Pathogens 4. Environmental and Social Influences on Infectious Disea...

  7. [Evolutionary medicine: an introduction. Evolutionary biology, a missing element in medical teaching].

    Science.gov (United States)

    Swynghedauw, Bernard

    2009-05-01

    The aim of this brief review article is to help to reconcile medicine with evolutionary biology, a subject that should be taught in medical school. Evolutionary medicine takes the view that contemporary ills are related to an incompatibility between the environment in which humans currently live and their genomes, which have been shaped by diferent environmental conditions during biological evolution. Human activity has recently induced acute environmental modifications that have profoundly changed the medical landscape. Evolutionary biology is an irreversible, ongoing and discontinuous process characterized by periods of stasis followed by accelerations. Evolutionary biology is determined by genetic mutations, which are selected either by Darwinian selective pressure or randomly by genetic drift. Most medical events result from a genome/environment conflict. Some may be purely genetic, as in monogenic diseases, and others purely environmental, such as traffic accidents. Nevertheless, in most common diseases the clinical landscape is determined by the conflict between these two factors, the genetic elements of which are gradually being unraveled Three examples are examined in depth:--The medical consequences of the greenhouse effect. The absence of excess mortality during recent heat waves suggests that the main determinant of mortality in the 2003 heatwave was heatstroke and old age. The projected long-term effects of global warming call for research on thermolysis, a forgotten branch of physiology.--The hygiene hypothesis postulates that the exponential rise in autoimmune and allergic diseases is linked to lesser exposure to infectious agents, possibly involving counter-regulatory factors such as IL-10.--The recent rise in the incidence of obesity and type 2 diabetes in rich countries can be considered to result from a conflict between a calorie-rich environment and gene variants that control appetite. These variants are currently being identified by genome

  8. [Evolutionary medicine: A new look on health and disease].

    Science.gov (United States)

    Bauduer, F

    2017-03-01

    Evolutionary medicine represents an innovative approach deriving from evolutionary biology. It includes the initial Darwin's view, its actualization in the light of progresses in genetics and also dissident theories (i.e. non gene-based) particularly epigenetics. This approach enables us to reconsider the pathophysiology of numerous diseases, as for instance, infection, and our so-called diseases of civilization especially obesity, type 2 diabetes, allergy or cancer. Evolutionary medicine may also improve our knowledge regarding inter-individual variation in susceptibility to disease or drugs. Furthermore, it points out the impact of our behaviors and environment on the genesis of a series of diseases. Copyright © 2016 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  9. Cooperative Evolutionary Game and Applications in Construction Supplier Tendency

    Directory of Open Access Journals (Sweden)

    Qianqian Shi

    2018-01-01

    Full Text Available Major construction projects have a great influence on the national economy and society, wherein cooperative relationship between construction suppliers plays an increasingly significant role in the overall supply chain system. However, the relationships between suppliers are noncontractual, multistage, dynamic, and complicated. To gain a deeper insight into the suppliers’ cooperative relationships, an evolutionary game model is developed to explore the cooperation tendency of multisuppliers. A replicator dynamic system is further formulated to investigate the evolutionary stable strategies of multisuppliers. Then, fourteen “when-then” type scenarios are concluded and classified into six different evolutionary tracks. Meanwhile, the critical influencing factors are identified. The results show that the suppliers’ production capacity, owner-supplier contract, and the owner’s incentive mechanism influence the cooperation tendency of suppliers directly. The managerial implications contribute to insightful references for a more stable cooperative relationship between the owner and suppliers.

  10. Individual-based modeling of ecological and evolutionary processes

    Science.gov (United States)

    DeAngelis, Donald L.; Mooij, Wolf M.

    2005-01-01

    Individual-based models (IBMs) allow the explicit inclusion of individual variation in greater detail than do classical differential-equation and difference-equation models. Inclusion of such variation is important for continued progress in ecological and evolutionary theory. We provide a conceptual basis for IBMs by describing five major types of individual variation in IBMs: spatial, ontogenetic, phenotypic, cognitive, and genetic. IBMs are now used in almost all subfields of ecology and evolutionary biology. We map those subfields and look more closely at selected key papers on fish recruitment, forest dynamics, sympatric speciation, metapopulation dynamics, maintenance of diversity, and species conservation. Theorists are currently divided on whether IBMs represent only a practical tool for extending classical theory to more complex situations, or whether individual-based theory represents a radically new research program. We feel that the tension between these two poles of thinking can be a source of creativity in ecology and evolutionary theory.

  11. Strongly coupled dust coulomb clusters

    International Nuclear Information System (INIS)

    Juan Wentau; Lai Yingju; Chen Mingheng; I Lin

    1999-01-01

    The structures and motions of quasi-2-dimensional strongly coupled dust Coulomb clusters with particle number N from few to hundreds in a cylindrical rf plasma trap are studied and compared with the results from the molecular dynamic simulation using more ideal models. Shell structures with periodic packing in different shells and intershell rotational motion dominated excitations are observed at small N. As N increases, the boundary has less effect, the system recovers to the triangular lattice with isotropic vortex type cooperative excitations similar to an infinite N system except the outer shell region. The above generic behaviors are mainly determined by the system symmetry and agree with the simulation results. The detailed interaction form causes minor effect such as the fine structure of packing

  12. phyloXML: XML for evolutionary biology and comparative genomics.

    Science.gov (United States)

    Han, Mira V; Zmasek, Christian M

    2009-10-27

    Evolutionary trees are central to a wide range of biological studies. In many of these studies, tree nodes and branches need to be associated (or annotated) with various attributes. For example, in studies concerned with organismal relationships, tree nodes are associated with taxonomic names, whereas tree branches have lengths and oftentimes support values. Gene trees used in comparative genomics or phylogenomics are usually annotated with taxonomic information, genome-related data, such as gene names and functional annotations, as well as events such as gene duplications, speciations, or exon shufflings, combined with information related to the evolutionary tree itself. The data standards currently used for evolutionary trees have limited capacities to incorporate such annotations of different data types. We developed a XML language, named phyloXML, for describing evolutionary trees, as well as various associated data items. PhyloXML provides elements for commonly used items, such as branch lengths, support values, taxonomic names, and gene names and identifiers. By using "property" elements, phyloXML can be adapted to novel and unforeseen use cases. We also developed various software tools for reading, writing, conversion, and visualization of phyloXML formatted data. PhyloXML is an XML language defined by a complete schema in XSD that allows storing and exchanging the structures of evolutionary trees as well as associated data. More information about phyloXML itself, the XSD schema, as well as tools implementing and supporting phyloXML, is available at http://www.phyloxml.org.

  13. Evolutionary biology today and the call for an extended synthesis.

    Science.gov (United States)

    Futuyma, Douglas J

    2017-10-06

    Evolutionary theory has been extended almost continually since the evolutionary synthesis (ES), but except for the much greater importance afforded genetic drift, the principal tenets of the ES have been strongly supported. Adaptations are attributable to the sorting of genetic variation by natural selection, which remains the only known cause of increase in fitness. Mutations are not adaptively directed, but as principal authors of the ES recognized, the material (structural) bases of biochemistry and development affect the variety of phenotypic variations that arise by mutation and recombination. Against this historical background, I analyse major propositions in the movement for an 'extended evolutionary synthesis'. 'Niche construction' is a new label for a wide variety of well-known phenomena, many of which have been extensively studied, but (as with every topic in evolutionary biology) some aspects may have been understudied. There is no reason to consider it a neglected 'process' of evolution. The proposition that phenotypic plasticity may engender new adaptive phenotypes that are later genetically assimilated or accommodated is theoretically plausible; it may be most likely when the new phenotype is not truly novel, but is instead a slight extension of a reaction norm already shaped by natural selection in similar environments. However, evolution in new environments often compensates for maladaptive plastic phenotypic responses. The union of population genetic theory with mechanistic understanding of developmental processes enables more complete understanding by joining ultimate and proximate causation; but the latter does not replace or invalidate the former. Newly discovered molecular phenomena have been easily accommodated in the past by elaborating orthodox evolutionary theory, and it appears that the same holds today for phenomena such as epigenetic inheritance. In several of these areas, empirical evidence is needed to evaluate enthusiastic speculation

  14. Darwin’s legacy in South African evolutionary biology

    Directory of Open Access Journals (Sweden)

    S. D. Johnson

    2010-02-01

    Full Text Available In the two decades after publication of the Origin of Species, Charles Darwin facilitated the publication of numerous scientific papers by settler naturalists in South Africa. This helped to establish the strong tradition of natural history which has characterised evolutionary research in South African museums, herbaria and universities. Significant developments in the early 20th century included the hominid fossil discoveries of Raymond Dart, Robert Broom, and others, but there was otherwise very little South African involvement in the evolutionary synthesis of the 1930s and 1940s. Evolutionary biology developed into a distinct discipline in South Africa during the 1970s and 1980s when it was dominated by mammalian palaeontology and a vigorous debate around species concepts. In the post-apartheid era, the main focus of evolutionary biology has been the construction of phylogenies for African plants and animals using molecular data, and the use of these phylogenies to answer questions about taxonomic classification and trait evolution. South African biologists have also recently contributed important evidence for some of Darwin’s ideas about plant–animal coevolution, sexual selection, and the role of natural selection in speciation. A bibliographic analysis shows that South African authors produce 2–3% of the world’s publications in the field of evolutionary biology, which is much higher than the value of about 0.5% for publications in all sciences. With its extraordinary biodiversity and well-developed research infrastructure, South Africa is an ideal laboratory from which to advance evolutionary research.

  15. Evolutionary rate patterns of the Gibberellin pathway genes

    Directory of Open Access Journals (Sweden)

    Zhang Fu-min

    2009-08-01

    Full Text Available Abstract Background Analysis of molecular evolutionary patterns of different genes within metabolic pathways allows us to determine whether these genes are subject to equivalent evolutionary forces and how natural selection shapes the evolution of proteins in an interacting system. Although previous studies found that upstream genes in the pathway evolved more slowly than downstream genes, the correlation between evolutionary rate and position of the genes in metabolic pathways as well as its implications in molecular evolution are still less understood. Results We sequenced and characterized 7 core structural genes of the gibberellin biosynthetic pathway from 8 representative species of the rice tribe (Oryzeae to address alternative hypotheses regarding evolutionary rates and patterns of metabolic pathway genes. We have detected significant rate heterogeneity among 7 GA pathway genes for both synonymous and nonsynonymous sites. Such rate variation is mostly likely attributed to differences of selection intensity rather than differential mutation pressures on the genes. Unlike previous argument that downstream genes in metabolic pathways would evolve more slowly than upstream genes, the downstream genes in the GA pathway did not exhibited the elevated substitution rate and instead, the genes that encode either the enzyme at the branch point (GA20ox or enzymes catalyzing multiple steps (KO, KAO and GA3ox in the pathway had the lowest evolutionary rates due to strong purifying selection. Our branch and codon models failed to detect signature of positive selection for any lineage and codon of the GA pathway genes. Conclusion This study suggests that significant heterogeneity of evolutionary rate of the GA pathway genes is mainly ascribed to differential constraint relaxation rather than the positive selection and supports the pathway flux theory that predicts that natural selection primarily targets enzymes that have the greatest control on fluxes.

  16. Evolutionary origin of rhizobium Nod factor signaling

    Science.gov (United States)

    Streng, Arend; op den Camp, Rik; Bisseling, Ton

    2011-01-01

    For over two decades now, it is known that the nodule symbiosis between legume plants and nitrogen fixing rhizobium bacteria is set in motion by the bacterial signal molecule named nodulation (Nod) factor.1 Upon Nod factor perception a signaling cascade is activated that is also essential for endomycorrhizal symbiosis (Fig. 1). This suggests that rhizobium co-opted the evolutionary far more ancient mycorrhizal signaling pathway in order to establish an endosymbiotic interaction with legumes.2 As arbuscular mycorrhizal fungi of the Glomeromycota phylum can establish a symbiosis with the vast majority of land plants, it is most probable that this signaling cascade is wide spread in the plant kingdom.3 However, Nod factor perception generally is considered to be unique to legumes. Two recent breakthroughs on the evolutionary origin of rhizobium Nod factor signaling demonstrate that this is not the case.4,5 The purification of Nod factor-like molecules excreted by the mycorrhizal fungus Glomus intraradices and the role of the LysM-type Nod factor receptor PaNFP in the non-legume Parasponia andersonii provide novel understanding on the evolution of rhizobial Nod factor signaling. PMID:21904113

  17. Network fluctuations hinder cooperation in evolutionary games.

    Science.gov (United States)

    Antonioni, Alberto; Tomassini, Marco

    2011-01-01

    In this paper we study the influence of random network fluctuations on the behavior of evolutionary games on Barabási-Albert networks. This network class has been shown to promote cooperation on social dilemmas such as the Prisoner's Dilemma and the Snowdrift games when the population network is fixed. Here we introduce exogenous random fluctuations of the network links through several noise models, and we investigate the evolutionary dynamics comparing them with the known static network case. The results we obtain show that even a moderate amount of random noise on the network links causes a significant loss of cooperation, to the point that cooperation vanishes altogether in the Prisoner's Dilemma when the noise rate is the same as the agents' strategy revision rate. The results appear to be robust since they are essentially the same whatever the type of the exogenous noise. Besides, it turns out that random network noise is more important than strategy noise in suppressing cooperation. Thus, even in the more favorable situation of accumulated payoff in which links have no cost, the mere presence of random external network fluctuations act as a powerful limitation to the attainment of high levels of cooperation.

  18. Applying evolutionary genetics to schistosome epidemiology.

    Science.gov (United States)

    Steinauer, Michelle L; Blouin, Michael S; Criscione, Charles D

    2010-05-01

    We review how molecular markers and evolutionary analysis have been applied to the study of schistosome parasites, important pathogens that infect over 200 million people worldwide. Topics reviewed include phylogenetics and biogeography, hybridization, infection within snails, mating systems, and genetic structure. Some interesting generalizations include that schistosome species hybridize frequently and have switched definitive hosts repeatedly in evolutionary time. We show that molecular markers can be used to infer epidemiologically relevant processes such as spatial variation in transmission, or to reveal complex patterns of mate choice. Analysis of genetic structure data shows that transmission foci can be structured by watershed boundaries, habitat types, and host species. We also discuss sampling and analytical problems that arise when using larvae to estimate genetic parameters of adult schistosome populations. Finally, we review pitfalls in methodologies such as genotyping very small individuals, statistical methods for identifying clonemates or for identifying sibling groups, and estimating allele frequencies from pooled egg samples. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  19. Empirical verification of evolutionary theories of aging.

    Science.gov (United States)

    Kyryakov, Pavlo; Gomez-Perez, Alejandra; Glebov, Anastasia; Asbah, Nimara; Bruno, Luigi; Meunier, Carolynne; Iouk, Tatiana; Titorenko, Vladimir I

    2016-10-25

    We recently selected 3 long-lived mutant strains of Saccharomyces cerevisiae by a lasting exposure to exogenous lithocholic acid. Each mutant strain can maintain the extended chronological lifespan after numerous passages in medium without lithocholic acid. In this study, we used these long-lived yeast mutants for empirical verification of evolutionary theories of aging. We provide evidence that the dominant polygenic trait extending longevity of each of these mutants 1) does not affect such key features of early-life fitness as the exponential growth rate, efficacy of post-exponential growth and fecundity; and 2) enhances such features of early-life fitness as susceptibility to chronic exogenous stresses, and the resistance to apoptotic and liponecrotic forms of programmed cell death. These findings validate evolutionary theories of programmed aging. We also demonstrate that under laboratory conditions that imitate the process of natural selection within an ecosystem, each of these long-lived mutant strains is forced out of the ecosystem by the parental wild-type strain exhibiting shorter lifespan. We therefore concluded that yeast cells have evolved some mechanisms for limiting their lifespan upon reaching a certain chronological age. These mechanisms drive the evolution of yeast longevity towards maintaining a finite yeast chronological lifespan within ecosystems.

  20. Before senescence: the evolutionary demography of ontogenesis.

    Science.gov (United States)

    Levitis, Daniel A

    2011-03-22

    The age-specific mortality curve for many species, including humans, is U-shaped: mortality declines with age in the developing cohort (ontogenescence) before increasing with age (senescence). The field of evolutionary demography has long focused on understanding the evolution of senescence while largely failing to address the evolution of ontogenescence. The current review is the first to gather the few available hypotheses addressing the evolution of ontogenescence, examine the basis and assumptions of each and ask what the phylogenetic extent of ontogenescence may be. Ontogenescence is among the most widespread of life-history traits, occurring in every population for which I have found sufficiently detailed data, in major groups throughout the eukaryotes, across many causes of death and many life-history types. Hypotheses seeking to explain ontogenescence include those based on kin selection, the acquisition of robustness, heterogeneous frailties and life-history optimization. I propose a further hypothesis, arguing that mortality drops with age because most transitions that could trigger the risks caused by genetic and developmental malfunctions are concentrated in early life. Of these hypotheses, only those that frame ontogenescence as an evolutionary by-product rather than an adaptation can explain the tremendous diversity of organisms and environments in which it occurs.

  1. The citation field of evolutionary economics

    NARCIS (Netherlands)

    Dolfsma, Wilfred; Leydesdorff, Loet

    2010-01-01

    Evolutionary economics has developed into an academic field of its own, institutionalized around, amongst others, the Journal of Evolutionary Economics (JEE). This paper analyzes the way and extent to which evolutionary economics has become an interdisciplinary journal, as its aim was: a journal

  2. Metal Catalysis with Nanostructured Metals Supported Inside Strongly Acidic Cross-linked Polymer Frameworks: Influence of Reduction Conditions of AuIII-containing Resins on Metal Nanoclusters Formation in Macroreticular and Gel-Type Materials

    Czech Academy of Sciences Publication Activity Database

    Calore, L.; Cavinato, g.; Canton, P.; Peruzzo, L.; Banavali, R.; Jeřábek, Karel; Corain, B.

    2012-01-01

    Roč. 391, AUG 30 (2012), s. 114-120 ISSN 0020-1693 Institutional support: RVO:67985858 Keywords : strongly acidic cross-linked polymer * frameworks * gold(0) nanoclusters Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.687, year: 2012

  3. Three Types of Social Integration Status among Children of Migrant Workers in China: Scenes of Superiority of City Residents, Co-Existence of Urban Culture and Rural Hometown Culture, and Weak Social Capital under Strong Policy Discourse

    Science.gov (United States)

    Qian, Liu

    2017-01-01

    Based on surveys and field work conducted in District C of Beijing City, the author identifies migrant children's social assimilation obstacles according to distinct school types: each school type offers different quality educational resources and is composed of migrant students at different socioeconomic levels. The survey data show that migrant…

  4. Schroedinger operators and evolutionary strategies

    International Nuclear Information System (INIS)

    Asselmeyer, T.

    1997-01-01

    First we introduce a simple model for the description of evolutionary algorithms, which is based on 2nd order partial differential equations for the distribution function of the individuals. Then we turn to the properties of Boltzmann's and Darwin's strategy. the next chapter is dedicated to the mathematical properties of Schroedinger operators. Both statements on the spectral density and their reproducibility during the simulation are summarized. The remaining of this chapter are dedicated to the analysis of the kernel as well as the dependence of the Schroedinger operator on the potential. As conclusion from the results of this chapter we obtain the classification of the strategies in dependence of the fitness. We obtain the classification of the evolutionary strategies, which are described by a 2nd order partial differential equation, in relation to their solution behaviour. Thereafter we are employed with the variation of the mutation distribution

  5. Incorporating Development Into Evolutionary Psychology

    OpenAIRE

    David F. Bjorklund

    2016-01-01

    Developmental thinking is gradually becoming integrated within mainstream evolutionary psychology. This is most apparent with respect to the role of parenting, with proponents of life history theory arguing that cognitive and behavioral plasticity early in life permits children to select different life history strategies, with such strategies being adaptive solutions to different fitness trade-offs. I argue that adaptations develop and are based on the highly plastic nature of infants’ and ch...

  6. Evolutionary dynamics of diploid populations

    Science.gov (United States)

    Desimone, Ralph; Newman, Timothy

    2003-10-01

    There has been much recent interest in constructing computer models of evolutionary dynamics. Typically these models focus on asexual population dynamics, which are appropriate for haploid organsims such as bacteria. Using a recently developed ``genome template'' model, we extend the algorithm to a sexual population of diploid organisms. We will present some early results showing the temporal evolution of mean fitness and genetic variation, and compare this to typical results from haploid populations.

  7. Passivity and Evolutionary Game Dynamics

    KAUST Repository

    Park, Shinkyu

    2018-03-21

    This paper investigates an energy conservation and dissipation -- passivity -- aspect of dynamic models in evolutionary game theory. We define a notion of passivity using the state-space representation of the models, and we devise systematic methods to examine passivity and to identify properties of passive dynamic models. Based on the methods, we describe how passivity is connected to stability in population games and illustrate stability of passive dynamic models using numerical simulations.

  8. Natural pedagogy as evolutionary adaptation

    OpenAIRE

    Csibra, Gergely; Gergely, György

    2011-01-01

    We propose that the cognitive mechanisms that enable the transmission of cultural knowledge by communication between individuals constitute a system of ‘natural pedagogy’ in humans, and represent an evolutionary adaptation along the hominin lineage. We discuss three kinds of arguments that support this hypothesis. First, natural pedagogy is likely to be human-specific: while social learning and communication are both widespread in non-human animals, we know of no example of social learning by...

  9. Evolutionary Theories in Environmental and Resource Economics: Approaches and Applications

    NARCIS (Netherlands)

    van den Bergh, J.C.J.M.; Gowdy, J.M.

    2000-01-01

    Recent advances in evolutionary theory have important implications for environmental economics. A short overview is offered of evolutionary thinking in economics. Subsequently, major concepts and approaches in evolutionary biology and evolutionary economics are presented and compared. Attention is

  10. Incorporating Development Into Evolutionary Psychology

    Directory of Open Access Journals (Sweden)

    David F. Bjorklund

    2016-09-01

    Full Text Available Developmental thinking is gradually becoming integrated within mainstream evolutionary psychology. This is most apparent with respect to the role of parenting, with proponents of life history theory arguing that cognitive and behavioral plasticity early in life permits children to select different life history strategies, with such strategies being adaptive solutions to different fitness trade-offs. I argue that adaptations develop and are based on the highly plastic nature of infants’ and children’s behavior/cognition/brains. The concept of evolved probabilistic cognitive mechanisms is introduced, defined as information processing mechanisms evolved to solve recurrent problems faced by ancestral populations that are expressed in a probabilistic fashion in each individual in a generation and are based on the continuous and bidirectional interaction over time at all levels of organization, from the genetic through the cultural. Early perceptual/cognitive biases result in behavior that, when occurring in a species-typical environment, produce continuous adaptive changes in behavior (and cognition, yielding adaptive outcomes. Examples from social learning and tool use are provided, illustrating the development of adaptations via evolved probabilistic cognitive mechanisms. The integration of developmental concepts into mainstream evolutionary psychology (and evolutionary concepts into mainstream developmental psychology will provide a clearer picture of what it means to be human.

  11. Evolutionary computation and QSAR research.

    Science.gov (United States)

    Aguiar-Pulido, Vanessa; Gestal, Marcos; Cruz-Monteagudo, Maykel; Rabuñal, Juan R; Dorado, Julian; Munteanu, Cristian R

    2013-06-01

    The successful high throughput screening of molecule libraries for a specific biological property is one of the main improvements in drug discovery. The virtual molecular filtering and screening relies greatly on quantitative structure-activity relationship (QSAR) analysis, a mathematical model that correlates the activity of a molecule with molecular descriptors. QSAR models have the potential to reduce the costly failure of drug candidates in advanced (clinical) stages by filtering combinatorial libraries, eliminating candidates with a predicted toxic effect and poor pharmacokinetic profiles, and reducing the number of experiments. To obtain a predictive and reliable QSAR model, scientists use methods from various fields such as molecular modeling, pattern recognition, machine learning or artificial intelligence. QSAR modeling relies on three main steps: molecular structure codification into molecular descriptors, selection of relevant variables in the context of the analyzed activity, and search of the optimal mathematical model that correlates the molecular descriptors with a specific activity. Since a variety of techniques from statistics and artificial intelligence can aid variable selection and model building steps, this review focuses on the evolutionary computation methods supporting these tasks. Thus, this review explains the basic of the genetic algorithms and genetic programming as evolutionary computation approaches, the selection methods for high-dimensional data in QSAR, the methods to build QSAR models, the current evolutionary feature selection methods and applications in QSAR and the future trend on the joint or multi-task feature selection methods.

  12. What's wrong with evolutionary biology?

    Science.gov (United States)

    Welch, John J

    2017-01-01

    There have been periodic claims that evolutionary biology needs urgent reform, and this article tries to account for the volume and persistence of this discontent. It is argued that a few inescapable properties of the field make it prone to criticisms of predictable kinds, whether or not the criticisms have any merit. For example, the variety of living things and the complexity of evolution make it easy to generate data that seem revolutionary (e.g. exceptions to well-established generalizations, or neglected factors in evolution), and lead to disappointment with existing explanatory frameworks (with their high levels of abstraction, and limited predictive power). It is then argued that special discontent stems from misunderstandings and dislike of one well-known but atypical research programme: the study of adaptive function, in the tradition of behavioural ecology. To achieve its goals, this research needs distinct tools, often including imaginary agency, and a partial description of the evolutionary process. This invites mistaken charges of narrowness and oversimplification (which come, not least, from researchers in other subfields), and these chime with anxieties about human agency and overall purpose. The article ends by discussing several ways in which calls to reform evolutionary biology actively hinder progress in the field.

  13. Evolutionary ecology of virus emergence.

    Science.gov (United States)

    Dennehy, John J

    2017-02-01

    The cross-species transmission of viruses into new host populations, termed virus emergence, is a significant issue in public health, agriculture, wildlife management, and related fields. Virus emergence requires overlap between host populations, alterations in virus genetics to permit infection of new hosts, and adaptation to novel hosts such that between-host transmission is sustainable, all of which are the purview of the fields of ecology and evolution. A firm understanding of the ecology of viruses and how they evolve is required for understanding how and why viruses emerge. In this paper, I address the evolutionary mechanisms of virus emergence and how they relate to virus ecology. I argue that, while virus acquisition of the ability to infect new hosts is not difficult, limited evolutionary trajectories to sustained virus between-host transmission and the combined effects of mutational meltdown, bottlenecking, demographic stochasticity, density dependence, and genetic erosion in ecological sinks limit most emergence events to dead-end spillover infections. Despite the relative rarity of pandemic emerging viruses, the potential of viruses to search evolutionary space and find means to spread epidemically and the consequences of pandemic viruses that do emerge necessitate sustained attention to virus research, surveillance, prophylaxis, and treatment. © 2016 New York Academy of Sciences.

  14. Cancer research meets evolutionary biology.

    Science.gov (United States)

    Pepper, John W; Scott Findlay, C; Kassen, Rees; Spencer, Sabrina L; Maley, Carlo C

    2009-02-01

    There is increasing evidence that Darwin's theory of evolution by natural selection provides insights into the etiology and treatment of cancer. On a microscopic scale, neoplastic cells meet the conditions for evolution by Darwinian selection: cell reproduction with heritable variability that affects cell survival and replication. This suggests that, like other areas of biological and biomedical research, Darwinian theory can provide a general framework for understanding many aspects of cancer, including problems of great clinical importance. With the availability of raw molecular data increasing rapidly, this theory may provide guidance in translating data into understanding and progress. Several conceptual and analytical tools from evolutionary biology can be applied to cancer biology. Two clinical problems may benefit most from the application of Darwinian theory: neoplastic progression and acquired therapeutic resistance. The Darwinian theory of cancer has especially profound implications for drug development, both in terms of explaining past difficulties, and pointing the way toward new approaches. Because cancer involves complex evolutionary processes, research should incorporate both tractable (simplified) experimental systems, and also longitudinal observational studies of the evolutionary dynamics of cancer in laboratory animals and in human patients. Cancer biology will require new tools to control the evolution of neoplastic cells.

  15. Strong Selection Significantly Increases Epistatic Interactions in the Long-Term Evolution of a Protein.

    Directory of Open Access Journals (Sweden)

    Aditi Gupta

    2016-03-01

    Full Text Available Epistatic interactions between residues determine a protein's adaptability and shape its evolutionary trajectory. When a protein experiences a changed environment, it is under strong selection to find a peak in the new fitness landscape. It has been shown that strong selection increases epistatic interactions as well as the ruggedness of the fitness landscape, but little is known about how the epistatic interactions change under selection in the long-term evolution of a protein. Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1 using protease sequences collected for almost a decade from both treated and untreated patients, to understand how epistasis changes and how those changes impact the long-term evolvability of a protein. We use an information-theoretic proxy for epistasis that quantifies the co-variation between sites, and show that positive information is a necessary (but not sufficient condition that detects epistasis in most cases. We analyze the "fossils" of the evolutionary trajectories of the protein contained in the sequence data, and show that epistasis continues to enrich under strong selection, but not for proteins whose environment is unchanged. The increase in epistasis compensates for the information loss due to sequence variability brought about by treatment, and facilitates adaptation in the increasingly rugged fitness landscape of treatment. While epistasis is thought to enhance evolvability via valley-crossing early-on in adaptation, it can hinder adaptation later when the landscape has turned rugged. However, we find no evidence that the HIV-1 protease has reached its potential for evolution after 9 years of adapting to a drug environment that itself is constantly changing. We suggest that the mechanism of encoding new information into pairwise interactions is central to protein evolution not just in HIV-1 protease, but for any protein adapting to a changing

  16. Ecological and evolutionary effects of stickleback on community structure.

    Directory of Open Access Journals (Sweden)

    Simone Des Roches

    Full Text Available Species' ecology and evolution can have strong effects on communities. Both may change concurrently when species colonize a new ecosystem. We know little, however, about the combined effects of ecological and evolutionary change on community structure. We simultaneously examined the effects of top-predator ecology and evolution on freshwater community parameters using recently evolved generalist and specialist ecotypes of three-spine stickleback (Gasterosteus aculeatus. We used a mesocosm experiment to directly examine the effects of ecological (fish presence and density and evolutionary (phenotypic diversity and specialization factors on community structure at lower trophic levels. We evaluated zooplankton biomass and composition, periphyton and phytoplankton chlorophyll-a concentration, and net primary production among treatments containing different densities and diversities of stickleback. Our results showed that both ecological and evolutionary differences in the top-predator affect different aspects of community structure and composition. Community structure, specifically the abundance of organisms at each trophic level, was affected by stickleback presence and density, whereas composition of zooplankton was influenced by stickleback diversity and specialization. Primary productivity, in terms of chlorophyll-a concentration and net primary production was affected by ecological but not evolutionary factors. Our results stress the importance of concurrently evaluating both changes in density and phenotypic diversity on the structure and composition of communities.

  17. Ecological and evolutionary effects of stickleback on community structure.

    Science.gov (United States)

    Des Roches, Simone; Shurin, Jonathan B; Schluter, Dolph; Harmon, Luke J

    2013-01-01

    Species' ecology and evolution can have strong effects on communities. Both may change concurrently when species colonize a new ecosystem. We know little, however, about the combined effects of ecological and evolutionary change on community structure. We simultaneously examined the effects of top-predator ecology and evolution on freshwater community parameters using recently evolved generalist and specialist ecotypes of three-spine stickleback (Gasterosteus aculeatus). We used a mesocosm experiment to directly examine the effects of ecological (fish presence and density) and evolutionary (phenotypic diversity and specialization) factors on community structure at lower trophic levels. We evaluated zooplankton biomass and composition, periphyton and phytoplankton chlorophyll-a concentration, and net primary production among treatments containing different densities and diversities of stickleback. Our results showed that both ecological and evolutionary differences in the top-predator affect different aspects of community structure and composition. Community structure, specifically the abundance of organisms at each trophic level, was affected by stickleback presence and density, whereas composition of zooplankton was influenced by stickleback diversity and specialization. Primary productivity, in terms of chlorophyll-a concentration and net primary production was affected by ecological but not evolutionary factors. Our results stress the importance of concurrently evaluating both changes in density and phenotypic diversity on the structure and composition of communities.

  18. The evolutionary advantage of limited network knowledge.

    Science.gov (United States)

    Larson, Jennifer M

    2016-06-07

    Groups of individuals have social networks that structure interactions within the groups; evolutionary theory increasingly uses this fact to explain the emergence of cooperation (Eshel and Cavalli-Sforza, 1982; Boyd and Richerson, 1988, 1989; Ohtsuki et al., 2006; Nowak et al., 2010; Van Veelen et al., 2012). This approach has resulted in a number of important insights for the evolution of cooperation in the biological and social sciences, but omits a key function of social networks that has persisted throughout recent evolutionary history (Apicella et al., 2012): their role in transmitting gossip about behavior within a group. Accounting for this well-established role of social networks among rational agents in a setting of indirect reciprocity not only shows a new mechanism by which the structure of networks is fitness-relevant, but also reveals that knowledge of social networks can be fitness-relevant as well. When groups enforce cooperation by sanctioning peers whom gossip reveals to have deviated, individuals in certain peripheral network positions are tempting targets of uncooperative behavior because gossip they share about misbehavior spreads slowly through the network. The ability to identify these individuals creates incentives to behave uncooperatively. Consequently, groups comprised of individuals who knew precise information about their social networks would be at a fitness disadvantage relative to groups of individuals with a coarser knowledge of their networks. Empirical work has consistently shown that modern humans know little about the structure of their own social networks and perform poorly when tasked with learning new ones. This robust empirical regularity may be the product of natural selection in an environment of strong selective pressure at the group level. Imprecise views of networks make enforcing cooperation easier. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Effects of Clonal Reproduction on Evolutionary Lag and Evolutionary Rescue.

    Science.gov (United States)

    Orive, Maria E; Barfield, Michael; Fernandez, Carlos; Holt, Robert D

    2017-10-01

    Evolutionary lag-the difference between mean and optimal phenotype in the current environment-is of keen interest in light of rapid environmental change. Many ecologically important organisms have life histories that include stage structure and both sexual and clonal reproduction, yet how stage structure and clonality interplay to govern a population's rate of evolution and evolutionary lag is unknown. Effects of clonal reproduction on mean phenotype partition into two portions: one that is phenotype dependent, and another that is genotype dependent. This partitioning is governed by the association between the nonadditive genetic plus random environmental component of phenotype of clonal offspring and their parents. While clonality slows phenotypic evolution toward an optimum, it can dramatically increase population survival after a sudden step change in optimal phenotype. Increased adult survival slows phenotypic evolution but facilitates population survival after a step change; this positive effect can, however, be lost given survival-fecundity trade-offs. Simulations indicate that the benefits of increased clonality under environmental change greatly depend on the nature of that change: increasing population persistence under a step change while decreasing population persistence under a continuous linear change requiring de novo variation. The impact of clonality on the probability of persistence for species in a changing world is thus inexorably linked to the temporal texture of the change they experience.

  20. Evolutionary Accessibility of Mutational Pathways

    Science.gov (United States)

    Franke, Jasper; Klözer, Alexander; de Visser, J. Arjan G. M.; Krug, Joachim

    2011-01-01

    Functional effects of different mutations are known to combine to the total effect in highly nontrivial ways. For the trait under evolutionary selection (‘fitness’), measured values over all possible combinations of a set of mutations yield a fitness landscape that determines which mutational states can be reached from a given initial genotype. Understanding the accessibility properties of fitness landscapes is conceptually important in answering questions about the predictability and repeatability of evolutionary adaptation. Here we theoretically investigate accessibility of the globally optimal state on a wide variety of model landscapes, including landscapes with tunable ruggedness as well as neutral ‘holey’ landscapes. We define a mutational pathway to be accessible if it contains the minimal number of mutations required to reach the target genotype, and if fitness increases in each mutational step. Under this definition accessibility is high, in the sense that at least one accessible pathway exists with a substantial probability that approaches unity as the dimensionality of the fitness landscape (set by the number of mutational loci) becomes large. At the same time the number of alternative accessible pathways grows without bounds. We test the model predictions against an empirical 8-locus fitness landscape obtained for the filamentous fungus Aspergillus niger. By analyzing subgraphs of the full landscape containing different subsets of mutations, we are able to probe the mutational distance scale in the empirical data. The predicted effect of high accessibility is supported by the empirical data and is very robust, which we argue reflects the generic topology of sequence spaces. Together with the restrictive assumptions that lie in our definition of accessibility, this implies that the globally optimal configuration should be accessible to genome wide evolution, but the repeatability of evolutionary trajectories is limited owing to the presence of a

  1. Evolutionary Origin of the Proepicardium

    Directory of Open Access Journals (Sweden)

    Elena Cano

    2013-05-01

    Full Text Available The embryonic epicardium and the cardiac mesenchyme derived from it are critical to heart development. The embryonic epicardium arises from an extracardiac progenitor tissue called the proepicardium, a proliferation of coelomic cells located at the limit between the liver and the sinus venosus. A proepicardium has not been described in invertebrates, and the evolutionary origin of this structure in vertebrates is unknown. We herein suggest that the proepicardium might be regarded as an evolutionary derivative from an ancient pronephric external glomerulus that has lost its excretory role. In fact, we previously described that the epicardium arises by cell migration from the primordia of the right pronephric external glomerulus in a representative of the most primitive vertebrate lineage, the lamprey Petromyzon marinus. In this review, we emphasize the striking similarities between the gene expression profiles of the proepicardium and the developing kidneys, as well as the parallelisms in the signaling mechanisms involved in both cases. We show some preliminary evidence about the existence of an inhibitory mechanism blocking glomerular differentiation in the proepicardium. We speculate as to the possibility that this developmental link between heart and kidney can be revealing a phylogenetically deeper association, supported by the existence of a heart-kidney complex in Hemichordates. Finally, we suggest that primitive hematopoiesis could be related with this heart-kidney complex, thus accounting for the current anatomical association of the hematopoietic stem cells with an aorta-gonad-mesonephros area. In summary, we think that our hypothesis can provide new perspectives on the evolutionary origin of the vertebrate heart.

  2. The evolutionary origins of patriarchy.

    Science.gov (United States)

    Smuts, B

    1995-03-01

    This article argues that feminist analyses of patriarchy should be expanded to address the evolutionary basis of male motivation to control female sexuality. Evidence from other primates of male sexual coercion and female resistance to it indicates that the sexual conflicts of interest that underlie patriarchy predate the emergence of the human species. Humans, however, exhibit more extensive male dominance and male control of female sexuality than is shown by most other primates. Six hypotheses are proposed to explain how, over the course of human evolution, this unusual degree of gender inequality came about. This approach emphasizes behavioral flexibility, cross-cultural variability in the degree of partriarchy, and possibilities for future change.

  3. Policy folklists and evolutionary theory.

    Science.gov (United States)

    O'Neill, Barry

    2014-07-22

    Policy folklists present a set of alleged historical facts seen as relevant to some social issue. Although the validity of these folklists is dubious, leaders and writers circulate them in the media, variants arise, and the lists continue on, sometimes for decades. Folklists are repeated because their messages are appealing and their users are credible. Because folklists are on the record, we can examine their origins and changes. This report draws an analogy with evolutionary theory and suggests that biological mechanisms of self-repair, boundary maintenance, plasticity, speciation, and predation have significant interpretations for folklists, and clarify how the lists win the credence of otherwise skeptical people.

  4. Evolutionary Games and Social Conventions

    DEFF Research Database (Denmark)

    Hansen, Pelle Guldborg

    2007-01-01

    Some thirty years ago Lewis published his Convention: A Philosophical Study (Lewis, 2002). This laid the foundation for a game-theoretic approach to social conventions, but became more famously known for its seminal analysis of common knowledge; the concept receiving its canonical analysis...... which any theory of convention must revolve. In response, the so-called evolutionary turn has developed. While retaining the broad framework, in which games are described in terms of strategies and payoffs, this marks a transition from the classical assumptions of perfect rationality and common...

  5. John Strong - 1941-2006

    CERN Document Server

    2006-01-01

    Our friend and colleague John Strong was cruelly taken from us by a brain tumour on 31 July, a few days before his 65th birthday. John started his career and obtained his PhD in a group from Westfield College, initially working on experiments at Rutherford Appleton Laboratory (RAL). From the early 1970s onwards, however, his research was focused on experiments in CERN, with several particularly notable contributions. The Omega spectrometer adopted a system John had originally developed for experiments at RAL using vidicon cameras (a type of television camera) to record the sparks in the spark chambers. This highly automated system allowed Omega to be used in a similar way to bubble chambers. He contributed to the success of NA1 and NA7, where he became heavily involved in the electronic trigger systems. In these experiments the Westfield group joined forces with Italian colleagues to measure the form factors of the pion and the kaon, and the lifetime of some of the newly discovered charm particles. Such h...

  6. Morphological modelling of strongly curved islands

    NARCIS (Netherlands)

    Roelvink, D.; Den Heijer, C.; Van Thiel De Vries, J.S.M.

    2013-01-01

    Land reclamations and island coasts often involve strongly curved shorelines, which are challenging to be properly modeled by numerical morphological models. Evaluation of the long term development of these types of coasts as well as their response to storm conditions requires proper representation

  7. Evolutionary developmental biology its roots and characteristics.

    Science.gov (United States)

    Morange, Michel

    2011-09-01

    The rise of evolutionary developmental biology was not the progressive isolation and characterization of developmental genes and gene networks. Many obstacles had to be overcome: the idea that all genes were more or less involved in development; the evidence that developmental processes in insects had nothing in common with those of vertebrates. Different lines of research converged toward the creation of evolutionary developmental biology, giving this field of research its present heterogeneity. This does not prevent all those working in the field from sharing the conviction that a precise characterization of evolutionary variations is required to fully understand the evolutionary process. Some evolutionary developmental biologists directly challenge the Modern Synthesis. I propose some ways to reconcile these apparently opposed visions of evolution. The turbulence seen in evolutionary developmental biology reflects the present entry of history into biology. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Conceptual Barriers to Progress Within Evolutionary Biology.

    Science.gov (United States)

    Laland, Kevin N; Odling-Smee, John; Feldman, Marcus W; Kendal, Jeremy

    2009-08-01

    In spite of its success, Neo-Darwinism is faced with major conceptual barriers to further progress, deriving directly from its metaphysical foundations. Most importantly, neo-Darwinism fails to recognize a fundamental cause of evolutionary change, "niche construction". This failure restricts the generality of evolutionary theory, and introduces inaccuracies. It also hinders the integration of evolutionary biology with neighbouring disciplines, including ecosystem ecology, developmental biology, and the human sciences. Ecology is forced to become a divided discipline, developmental biology is stubbornly difficult to reconcile with evolutionary theory, and the majority of biologists and social scientists are still unhappy with evolutionary accounts of human behaviour. The incorporation of niche construction as both a cause and a product of evolution removes these disciplinary boundaries while greatly generalizing the explanatory power of evolutionary theory.

  9. The structure of microbial evolutionary theory.

    Science.gov (United States)

    Sapp, J

    2007-12-01

    The study of microbial phylogeny and evolution has emerged as an interdisciplinary synthesis, divergent in both methods and concepts from the classical evolutionary biology. The deployment of macromolecular sequencing in microbial classification has provided a deep evolutionary taxonomy hitherto deemed impossible. Microbial phylogenetics has greatly transformed the landscape of evolutionary biology, not only in revitalizing the field in the pursuit of life's history over billions of years, but also in transcending the structure of thought that has shaped evolutionary theory since the time of Darwin. A trio of primary phylogenetic lineages, along with the recognition of symbiosis and lateral gene transfer as fundamental processes of evolutionary innovation, are core principles of microbial evolutionary biology today. Their scope and significance remain contentious among evolutionists.

  10. The Evolutionary Puzzle of Suicide

    Directory of Open Access Journals (Sweden)

    Henri-Jean Aubin

    2013-12-01

    Full Text Available Mechanisms of self-destruction are difficult to reconcile with evolution’s first rule of thumb: survive and reproduce. However, evolutionary success ultimately depends on inclusive fitness. The altruistic suicide hypothesis posits that the presence of low reproductive potential and burdensomeness toward kin can increase the inclusive fitness payoff of self-removal. The bargaining hypothesis assumes that suicide attempts could function as an honest signal of need. The payoff may be positive if the suicidal person has a low reproductive potential. The parasite manipulation hypothesis is founded on the rodent—Toxoplasma gondii host-parasite model, in which the parasite induces a “suicidal” feline attraction that allows the parasite to complete its life cycle. Interestingly, latent infection by T. gondii has been shown to cause behavioral alterations in humans, including increased suicide attempts. Finally, we discuss how suicide risk factors can be understood as nonadaptive byproducts of evolved mechanisms that malfunction. Although most of the mechanisms proposed in this article are largely speculative, the hypotheses that we raise accept self-destructive behavior within the framework of evolutionary theory.

  11. Evolutionary development of tensegrity structures.

    Science.gov (United States)

    Lobo, Daniel; Vico, Francisco J

    2010-09-01

    Contributions from the emerging fields of molecular genetics and evo-devo (evolutionary developmental biology) are greatly benefiting the field of evolutionary computation, initiating a promise of renewal in the traditional methodology. While direct encoding has constituted a dominant paradigm, indirect ways to encode the solutions have been reported, yet little attention has been paid to the benefits of the proposed methods to real problems. In this work, we study the biological properties that emerge by means of using indirect encodings in the context of form-finding problems. A novel indirect encoding model for artificial development has been defined and applied to an engineering structural-design problem, specifically to the discovery of tensegrity structures. This model has been compared with a direct encoding scheme. While the direct encoding performs similarly well to the proposed method, indirect-based results typically outperform the direct-based results in aspects not directly linked to the nature of the problem itself, but to the emergence of properties found in biological organisms, like organicity, generalization capacity, or modularity aspects which are highly valuable in engineering. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  12. Evolutionary Biology Needs Wild Microbiomes.

    Science.gov (United States)

    Hird, Sarah M

    2017-01-01

    The microbiome is a vital component to the evolution of a host and much of what we know about the microbiome derives from studies on humans and captive animals. But captivity alters the microbiome and mammals have unique biological adaptations that affect their microbiomes (e.g., milk). Birds represent over 30% of known tetrapod diversity and possess their own suite of adaptations relevant to the microbiome. In a previous study, we showed that 59 species of birds displayed immense variation in their microbiomes and host (bird) taxonomy and ecology were most correlated with the gut microbiome. In this Frontiers Focused Review, I put those results in a broader context by discussing how collecting and analyzing wild microbiomes contributes to the main goals of evolutionary biology and the specific ways that birds are unique microbial hosts. Finally, I outline some of the methodological considerations for adding microbiome sampling to the research of wild animals and urge researchers to do so. To truly understand the evolution of a host, we need to understand the millions of microorganisms that inhabit it as well: evolutionary biology needs wild microbiomes.

  13. Evolutionary epistemology a multiparadigm program

    CERN Document Server

    Pinxten, Rik

    1987-01-01

    This volume has its already distant origin in an inter­national conference on Evolutionary Epistemology the editors organized at the University of Ghent in November 1984. This conference aimed to follow up the endeavor started at the ERISS (Epistemologically Relevant Internalist Sociology of Science) conference organized by Don Campbell and Alex Rosen­ berg at Cazenovia Lake, New York, in June 1981, whilst in­ jecting the gist of certain current continental intellectual developments into a debate whose focus, we thought, was in danger of being narrowed too much, considering the still underdeveloped state of affairs in the field. Broadly speaking, evolutionary epistemology today con­ sists of two interrelated, yet qualitatively distinct inves­ tigative efforts. Both are drawing on Darwinian concepts, which may explain why many people have failed to discriminate them. One is the study of the evolution of the cognitive apparatus of living organisms, which is first and foremost the province of biologists and...

  14. Evolutionary expansion of the Monogenea.

    Science.gov (United States)

    Kearn, G C

    1994-12-01

    The evolutionary expansion of the monogeneans has taken place in parallel with the diversification of the fish-like vertebrates. In this article the main trends in monogenean evolution are traced from a hypothetical skin-parasitic ancestor on early vertebrates. Special consideration is given to the following topics: early divergence between skin feeders and blood feeders; diversification and specialization of the haptor for attachment to skin; transfer from host to host, viviparity and the success of the gyrodactylids; predation on skin parasites and camouflage; colonization of the buccal and branchial cavities; diversification and specialization of the haptor for attachment to the gills; phoresy in gill parasites; the development of endoparasitism and the origin of the cestodes; the success of dactylogyroidean gill parasites; the uniqueness of the polyopisthocotyleans; ovoviviparity and the colonization of the tetrapods. Host specificity has been the guiding force of coevolution between monogeneans and their vertebrate hosts, but the establishment of monogeneans on unrelated hosts sharing the same environment (host-switching) may have been underestimated. Host-switching has provided significant opportunities for evolutionary change of direction and is probably responsible for the establishment of monogeneans on cephalopod molluscs, on the hippopotamus and possibly on chelonians. There are indications that host-switching may be more common in monogeneans that spread by direct transfer of adults/juveniles from host to host. A limitation on the further expansion of monogeneans is the need for water for the dispersal of the infective larva (oncomiracidium).

  15. Diversity of neighborhoods promotes cooperation in evolutionary social dilemmas

    Science.gov (United States)

    Ma, Yongjuan; Lu, Jun; Shi, Lei

    2017-02-01

    Explaining the evolution of cooperative behavior is one of the most important and interesting problems in a myriad of disciplines, such as evolutionary biology, mathematics, statistical physics, social science and economics Up to now, there have been a great number of works aiming to this issue with the help of evolutionary game theory. However, vast majority of existing literatures simply assume that the interaction neighborhood and replacement neighborhood are symmetric, which seems inconsistent with real-world cases. In this paper, we consider the asymmetrical neighborhood: player of type A, whose factor is controlled by a parameter τ, has four interaction neighbors and four replacement neighbors, while player of type B, whose factor is controlled by a parameter 1 - τ, possess eight interaction neighbors and four replacement neighbors. By means of numerous Monte Carlo simulations, we found that middle τ can make the cooperation reach the highest level While for this finding, its robustness can be further validated in more games.

  16. Synonymous genes explore different evolutionary landscapes.

    Directory of Open Access Journals (Sweden)

    Guillaume Cambray

    2008-11-01

    Full Text Available The evolutionary potential of a gene is constrained not only by the amino acid sequence of its product, but by its DNA sequence as well. The topology of the genetic code is such that half of the amino acids exhibit synonymous codons that can reach different subsets of amino acids from each other through single mutation. Thus, synonymous DNA sequences should access different regions of the protein sequence space through a limited number of mutations, and this may deeply influence the evolution of natural proteins. Here, we demonstrate that this feature can be of value for manipulating protein evolvability. We designed an algorithm that, starting from an input gene, constructs a synonymous sequence that systematically includes the codons with the most different evolutionary perspectives; i.e., codons that maximize accessibility to amino acids previously unreachable from the template by point mutation. A synonymous version of a bacterial antibiotic resistance gene was computed and synthesized. When concurrently submitted to identical directed evolution protocols, both the wild type and the recoded sequence led to the isolation of specific, advantageous phenotypic variants. Simulations based on a mutation isolated only from the synthetic gene libraries were conducted to assess the impact of sub-functional selective constraints, such as codon usage, on natural adaptation. Our data demonstrate that rational design of synonymous synthetic genes stands as an affordable improvement to any directed evolution protocol. We show that using two synonymous DNA sequences improves the overall yield of the procedure by increasing the diversity of mutants generated. These results provide conclusive evidence that synonymous coding sequences do experience different areas of the corresponding protein adaptive landscape, and that a sequence's codon usage effectively constrains the evolution of the encoded protein.

  17. The emerging empirics of evolutionary economic geography

    OpenAIRE

    Ron Boschma; KOen Frenken

    2010-01-01

    Following last decadeÕs programmatic papers on Evolutionary Economic Geography, we report on recent empirical advances and how this empirical work can be positioned vis-ˆ-vis other strands of research in economic geography. First, we review studies on the path dependent nature of clustering, and how the evolutionary perspective relates to that of New Economic Geography. Second, we discuss research on agglomeration externalities in Regional Science, and how Evolutionary Economic Geography cont...

  18. Evolutionary computation for dynamic optimization problems

    CERN Document Server

    Yao, Xin

    2013-01-01

    This book provides a compilation on the state-of-the-art and recent advances of evolutionary computation for dynamic optimization problems. The motivation for this book arises from the fact that many real-world optimization problems and engineering systems are subject to dynamic environments, where changes occur over time. Key issues for addressing dynamic optimization problems in evolutionary computation, including fundamentals, algorithm design, theoretical analysis, and real-world applications, are presented. "Evolutionary Computation for Dynamic Optimization Problems" is a valuable reference to scientists, researchers, professionals and students in the field of engineering and science, particularly in the areas of computational intelligence, nature- and bio-inspired computing, and evolutionary computation.

  19. Evolutionary Autonomous Health Monitoring System (EAHMS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For supporting NASA's Robotics, Tele-Robotics and Autonomous Systems Roadmap, we are proposing the "Evolutionary Autonomous Health Monitoring System" (EAHMS) for...

  20. Evolutionary status of AA Doradus: still an enigma?

    International Nuclear Information System (INIS)

    Sarna, M.J.

    1985-01-01

    The evolutionary scenarios for AA Dor are reconsidered using new contraction times for degenerate red dwarfs. It is found that both types of models considered by Paczynski (1980) with the primary being either an hydrogen shell burning helium white dwarf or a double shell burning carbon-oxygen white dwarf are consistent with the available data. The second model requires a very narrow range of the initial parameters of the binary system. 26 refs. (author)

  1. In silico analysis of evolutionary patterns in restriction endonucleases.

    Science.gov (United States)

    Singh, Tiratha Raj; Pardasani, Kamal Raj

    2009-01-01

    Restriction endonucleases represent one of the best studied examples of DNA binding proteins. Type II restriction endonucleases recognize short sequences of foreign DNA and cleave the target on both strands with remarkable sequence specificity. Type II restriction endonucleases are part of restriction modification systems. Restriction modification systems occur ubiquitously among bacteria and archaea. Restriction endonucleases are indispensable tools in molecular biology and biotechnology. They are important model system for specific protein-nucleic acid interactions and also serve as good example for investigating structural, functional and evolutionary relationships among various biomolecules. The interaction between restriction endonucleases and their recognition sequences plays a crucial role in biochemical activities like catalytic site/metal binding, DNA repair and recombination etc. We study various patterns in restriction endonucleases type II and analyzed their structural, functional and evolutionary role. Our studies support X-ray crystallographic studies, arguing for divergence and molecular evolution. Conservation patterns of the nuclease superfamily have also been analyzed by estimating site-specific evolutionary rates for the analyzed structures related to respective chains in this study.

  2. Symmetric solutions of evolutionary partial differential equations

    Science.gov (United States)

    Bruell, Gabriele; Ehrnström, Mats; Geyer, Anna; Pei, Long

    2017-10-01

    We show that for a large class of evolutionary nonlinear and nonlocal partial differential equations, symmetry of solutions implies very restrictive properties of the solutions and symmetry axes. These restrictions are formulated in terms of three principles, based on the structure of the equations. The first principle covers equations that allow for steady solutions and shows that any spatially symmetric solution is in fact steady with a speed determined by the motion of the axis of symmetry at the initial time. The second principle includes equations that admit breathers and steady waves, and therefore is less strong: it holds that the axes of symmetry are constant in time. The last principle is a mixed case, when the equation contains terms of the kind from both earlier principles, and there may be different outcomes; for a class of such equations one obtains that a spatially symmetric solution must be constant in both time and space. We list and give examples of more than 30 well-known equations and systems in one and several dimensions satisfying these principles; corresponding results for weak formulations of these equations may be attained using the same techniques. Our investigation is a generalisation of a local and one-dimensional version of the first principle from Ehrnström et al (2009 Int. Math. Res. Not. 2009 4578-96) to nonlocal equations, systems and higher dimensions, as well as a study of the standing and mixed cases.

  3. The evolutionary dynamics of bluetongue virus.

    Science.gov (United States)

    Carpi, Giovanna; Holmes, Edward C; Kitchen, Andrew

    2010-06-01

    Bluetongue virus (BTV) is a midge-borne member of the genus Orbivirus that causes an eponymous debilitating livestock disease of great agricultural impact and which has expanded into Europe in recent decades. Reassortment among the ten segments comprising the double-stranded (ds) RNA genome of BTV has played an important role in generating the epidemic strains of this virus in Europe. In this study, we investigated the dynamics of BTV genome segment evolution utilizing time-structured data sets of complete sequences from four segments, totalling 290 sequences largely sampled from ruminant hosts. Our analysis revealed that BTV genome segments generally evolve under strong purifying selection and at substitution rates that are generally lower (mean rates of approximately 0.5-7 x 10(-4) nucleotide substitutions per site, per year) than vector-borne positive-sense viruses with single-strand (ss) RNA genomes. These also represent the most robust estimates of the nucleotide substitution rate in a dsRNA virus generated to date. Additionally, we determined that patterns of geographic structure and times to most recent common ancestor differ substantially between each segment, including a relatively recent origin for the diversity of segment 10 within the past millennium. Together, these findings demonstrate the effect of reassortment to decouple the evolutionary dynamics of BTV genome segments.

  4. Evolutionary stability of mixed strategies on graphs

    International Nuclear Information System (INIS)

    Li, Yan; Liu, Xinsheng; Claussen, Jens Christian

    2016-01-01

    Up to the present time, the study of evolutionary dynamics mostly focused on pure strategy games in finite discrete strategy space, either in well-mixed or structured populations. In this paper, we study mixed strategy games in continuous strategy space on graphs of degree k . Each player is arranged on a vertex of the graph. The edges denote the interaction between two individuals. In the limit of weak selection, we first derive the payoff functions of two mixed strategies under three different updating rules, named birth–death, death–birth and imitation. Then we obtain the conditions for a strategy being a continuously stable strategy (CSS), and we also confirm that the equilibrium distribution corresponding to the CSS is neighborhood attracting and strongly uninvadable. Finally, we apply our theory to the prisoner’s dilemma and the snowdrift game to obtain possible CSS. Simulations are performed for the two special games and the results are well consistent with the conclusions we made. (paper)

  5. Modelling Evolutionary Algorithms with Stochastic Differential Equations.

    Science.gov (United States)

    Heredia, Jorge Pérez

    2017-11-20

    There has been renewed interest in modelling the behaviour of evolutionary algorithms (EAs) by more traditional mathematical objects, such as ordinary differential equations or Markov chains. The advantage is that the analysis becomes greatly facilitated due to the existence of well established methods. However, this typically comes at the cost of disregarding information about the process. Here, we introduce the use of stochastic differential equations (SDEs) for the study of EAs. SDEs can produce simple analytical results for the dynamics of stochastic processes, unlike Markov chains which can produce rigorous but unwieldy expressions about the dynamics. On the other hand, unlike ordinary differential equations (ODEs), they do not discard information about the stochasticity of the process. We show that these are especially suitable for the analysis of fixed budget scenarios and present analogues of the additive and multiplicative drift theorems from runtime analysis. In addition, we derive a new more general multiplicative drift theorem that also covers non-elitist EAs. This theorem simultaneously allows for positive and negative results, providing information on the algorithm's progress even when the problem cannot be optimised efficiently. Finally, we provide results for some well-known heuristics namely Random Walk (RW), Random Local Search (RLS), the (1+1) EA, the Metropolis Algorithm (MA), and the Strong Selection Weak Mutation (SSWM) algorithm.

  6. Evolutionary dynamics of Newcastle disease virus

    Science.gov (United States)

    Miller, P.J.; Kim, L.M.; Ip, Hon S.; Afonso, C.L.

    2009-01-01

    A comprehensive dataset of NDV genome sequences was evaluated using bioinformatics to characterize the evolutionary forces affecting NDV genomes. Despite evidence of recombination in most genes, only one event in the fusion gene of genotype V viruses produced evolutionarily viable progenies. The codon-associated rate of change for the six NDV proteins revealed that the highest rate of change occurred at the fusion protein. All proteins were under strong purifying (negative) selection; the fusion protein displayed the highest number of amino acids under positive selection. Regardless of the phylogenetic grouping or the level of virulence, the cleavage site motif was highly conserved implying that mutations at this site that result in changes of virulence may not be favored. The coding sequence of the fusion gene and the genomes of viruses from wild birds displayed higher yearly rates of change in virulent viruses than in viruses of low virulence, suggesting that an increase in virulence may accelerate the rate of NDV evolution. ?? 2009 Elsevier Inc.

  7. Evolutionary significance of ageing in the wild.

    Science.gov (United States)

    Kowald, Axel; Kirkwood, Thomas B L

    2015-11-01

    Human lifespan has risen dramatically over the last 150 years, leading to a significant increase in the fraction of aged people in the population. Until recently it was believed that this contrasted strongly with the situation in wild populations of animals, where the likelihood of encountering demonstrably senescent individuals was believed to be negligible. Over the recent years, however, a series of field studies has appeared that shows ageing can also be observed for many species in the wild. We discuss here the relevance of this finding for the different evolutionary theories of ageing, since it has been claimed that ageing in the wild is incompatible with the so-called non-adaptive (non-programmed) theories, i.e. those in which ageing is presumed not to offer a direct selection benefit. We show that a certain proportion of aged individuals in the population is fully compatible with the antagonistic pleiotropy and the disposable soma theories, while it is difficult to reconcile with the mutation accumulation theory. We also quantify the costs of ageing using life history data from recent field studies and a range of possible metrics. We discuss the merits and problems of the different metrics and also introduce a new metric, yearly death toll, that aims directly at quantifying the deaths caused by the ageing process. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  9. Four types of interference competition and their impacts on the ecology and evolution of size-structured populations and communities

    DEFF Research Database (Denmark)

    Zhang, Lai; Andersen, Ken Haste; Dieckmann, Ulf

    2015-01-01

    We investigate how four types of interference competition - which alternatively affect foraging, metabolism, survival, and reproduction - impact the ecology and evolution of size-structured populations. Even though all four types of interference competition reduce population biomass, interference...... interference is strong. The evolutionary response to survival interference and reproductive interference is always larger maturation size. We also investigate how the four types of interference competition impact the evolutionary dynamics and resultant diversity and trophic structure of size......-structured communities. Like other types of trait-mediated competition, all four types of interference competition can induce disruptive selection and thus promote initial diversification. Even though foraging interference and reproductive interference are more potent in promoting initial diversification, they catalyze...

  10. Numerical and Evolutionary Optimization Workshop

    CERN Document Server

    Trujillo, Leonardo; Legrand, Pierrick; Maldonado, Yazmin

    2017-01-01

    This volume comprises a selection of works presented at the Numerical and Evolutionary Optimization (NEO) workshop held in September 2015 in Tijuana, Mexico. The development of powerful search and optimization techniques is of great importance in today’s world that requires researchers and practitioners to tackle a growing number of challenging real-world problems. In particular, there are two well-established and widely known fields that are commonly applied in this area: (i) traditional numerical optimization techniques and (ii) comparatively recent bio-inspired heuristics. Both paradigms have their unique strengths and weaknesses, allowing them to solve some challenging problems while still failing in others. The goal of the NEO workshop series is to bring together people from these and related fields to discuss, compare and merge their complimentary perspectives in order to develop fast and reliable hybrid methods that maximize the strengths and minimize the weaknesses of the underlying paradigms. Throu...

  11. Quantum Mechanics predicts evolutionary biology.

    Science.gov (United States)

    Torday, J S

    2018-01-11

    Nowhere are the shortcomings of conventional descriptive biology more evident than in the literature on Quantum Biology. In the on-going effort to apply Quantum Mechanics to evolutionary biology, merging Quantum Mechanics with the fundamentals of evolution as the First Principles of Physiology-namely negentropy, chemiosmosis and homeostasis-offers an authentic opportunity to understand how and why physics constitutes the basic principles of biology. Negentropy and chemiosmosis confer determinism on the unicell, whereas homeostasis constitutes Free Will because it offers a probabilistic range of physiologic set points. Similarly, on this basis several principles of Quantum Mechanics also apply directly to biology. The Pauli Exclusion Principle is both deterministic and probabilistic, whereas non-localization and the Heisenberg Uncertainty Principle are both probabilistic, providing the long-sought after ontologic and causal continuum from physics to biology and evolution as the holistic integration recognized as consciousness for the first time. Copyright © 2018. Published by Elsevier Ltd.

  12. Markov Networks in Evolutionary Computation

    CERN Document Server

    Shakya, Siddhartha

    2012-01-01

    Markov networks and other probabilistic graphical modes have recently received an upsurge in attention from Evolutionary computation community, particularly in the area of Estimation of distribution algorithms (EDAs).  EDAs have arisen as one of the most successful experiences in the application of machine learning methods in optimization, mainly due to their efficiency to solve complex real-world optimization problems and their suitability for theoretical analysis. This book focuses on the different steps involved in the conception, implementation and application of EDAs that use Markov networks, and undirected models in general. It can serve as a general introduction to EDAs but covers also an important current void in the study of these algorithms by explaining the specificities and benefits of modeling optimization problems by means of undirected probabilistic models. All major developments to date in the progressive introduction of Markov networks based EDAs are reviewed in the book. Hot current researc...

  13. Language and imagination: Evolutionary explorations.

    Science.gov (United States)

    Reuland, Eric

    2017-10-01

    This article provides a functional analysis of the conditions for language to emerge, and analyzes its role in imagination. It starts with some initial reflections on imagination and its evolutionary beginnings in relation to the role of working memory and tool use by chimpanzees and humans up to modernity. It then presents an analysis of what it takes to develop language, and how language gives rise to higher orders of imagination. An important theme in the discussion is which of the changes in the development leading to language may have been gradual and which changes must reflect a discontinuity. It concludes with a paradoxical property of imagination: One part of our mind is able to imagine and create systems that another part of our mind is unable to deal with. It shows how this tension manifests itself in the notion of an impossible language, but crucially also in conceptions of human society at large. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Steps towards an evolutionary physics

    CERN Document Server

    Tiezzi, E

    2006-01-01

    If thermodynamics is to physics as logic is to philosophy, recent theoretical advancements lend new coherence to the marvel and dynamism of life on Earth. Enzo Tiezzi's "Steps Towards an Evolutionary Physics" is a primer and guide, to those who would to stand on the shoulders of giants to attain this view: Heisenberg, Planck, Bateson, Varela, and Prigogine as well as notable contemporary scientists. The adventure of such a free and enquiring spirit thrives not so much on answers as on new questions. The book offers a new gestalt on the uncertainty principle and concept of probability. A wide range of examples, enigmas, and paradoxes lead one's imagination on an exquisite dance. Among the applications are: songs and shapes of nature, oscillatory reactions, orientors, goal functions and configurations of processes, and "dissipative structures and the city". Ecodynamics is a new science, which proposes a cross-fertilization between Charles Darwin and Ilya Prigogine. As an enigma in thermodynamics, Entropy forms ...

  15. Evolutionary design assistants for architecture

    Directory of Open Access Journals (Sweden)

    N. Onur Sönmez

    2015-04-01

    Full Text Available In its parallel pursuit of an increased competitivity for design offices and more pleasurable and easier workflows for designers, artificial design intelligence is a technical, intellectual, and political challenge. While human-machine cooperation has become commonplace through Computer Aided Design (CAD tools, a more improved collaboration and better support appear possible only through an endeavor into a kind of artificial design intelligence, which is more sensitive to the human perception of affairs. Considered as part of the broader Computational Design studies, the research program of this quest can be called Artificial / Autonomous / Automated Design (AD. The current available level of Artificial Intelligence (AI for design is limited and a viable aim for current AD would be to develop design assistants that are capable of producing drafts for various design tasks. Thus, the overall aim of this thesis is the development of approaches, techniques, and tools towards artificial design assistants that offer a capability for generating drafts for sub-tasks within design processes. The main technology explored for this aim is Evolutionary Computation (EC, and the target design domain is architecture. The two connected research questions of the study concern, first, the investigation of the ways to develop an architectural design assistant, and secondly, the utilization of EC for the development of such assistants. While developing approaches, techniques, and computational tools for such an assistant, the study also carries out a broad theoretical investigation into the main problems, challenges, and requirements towards such assistants on a rather overall level. Therefore, the research is shaped as a parallel investigation of three main threads interwoven along several levels, moving from a more general level to specific applications. The three research threads comprise, first, theoretical discussions and speculations with regard to both

  16. Strong WW Interaction at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pelaez, Jose R

    1998-12-14

    We present a brief pedagogical introduction to the Effective Electroweak Chiral Lagrangians, which provide a model independent description of the WW interactions in the strong regime. When it is complemented with some unitarization or a dispersive approach, this formalism allows the study of the general strong scenario expected at the LHC, including resonances.

  17. Perceived consequences of evolution: College students perceive negative personal and social impact in evolutionary theory

    Science.gov (United States)

    Brem, Sarah K.; Ranney, Michael; Schindel, Jennifer

    2003-03-01

    Evolutionary science has consequences for individuals and society, ranging from the way we interpret human behavior to our notions of spirituality and the purpose of our existence. Popular portrayals of evolution depict a paradoxical theory, a source of knowledge and human connections, but also a threat to our humanity and freedom. Using quantitative and qualitative methodology, we examined how college-educated adults (n = 135) from diverse ethnic and religious backgrounds perceive the impact of evolutionary theory on individuals and society. We identified a continuum of perspectives, ranging from strong creationist to strong evolutionist. Using the model of knowledge as an ecology (Demastes, Good, & Peebles, Science Education, 79, 637-666, 1995; Nardi & O'Day, Information ecologies: Using technology with heart, MIT Press, Cambridge, MA, 1999), we examined the relationships among participants' beliefs, their perceptions regarding the social and personal impact of evolutionary theory, their prior exposure to and knowledge of evolutionary theory, and their opinions regarding the teaching of evolution. Evolutionists and creationists differed in their prior exposure to evolutionary theory, and their opinions about some aspects of teaching, but showed striking similarities regarding perceived impact. All groups viewed the consequences of accepting evolutionary principles in a way that might be considered undesirable: increased selfishness and racism, decreased spirituality, and a decreased sense of purpose and self-determination. From a science education perspective, this one-sided interpretation is troublesome because it runs counter to the available evidence and theories in evolutionary science, and we consider ways of fostering more balanced presentation and appraisal of evolutionary theory.

  18. Strong-back safety latch

    International Nuclear Information System (INIS)

    DeSantis, G.N.

    1995-01-01

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch

  19. Strong-back safety latch

    Energy Technology Data Exchange (ETDEWEB)

    DeSantis, G.N.

    1995-03-06

    The calculation decides the integrity of the safety latch that will hold the strong-back to the pump during lifting. The safety latch will be welded to the strong-back and will latch to a 1.5-in. dia cantilever rod welded to the pump baseplate. The static and dynamic analysis shows that the safety latch will hold the strong-back to the pump if the friction clamps fail and the pump become free from the strong-back. Thus, the safety latch will meet the requirements of the Lifting and Rigging Manual for under the hook lifting for static loading; it can withstand shock loads from the strong-back falling 0.25 inch.

  20. Structured synthesis of MEMS using evolutionary approaches

    DEFF Research Database (Denmark)

    Fan, Zhun; Wang, Jiachuan; Achiche, Sofiane

    2008-01-01

    In this paper, we discuss the hierarchy that is involved in a typical MEMS design and how evolutionary approaches can be used to automate the hierarchical synthesis process for MEMS. The paper first introduces the flow of a structured MEMS design process and emphasizes that system-level lumped...... the integrated design automation idea using these evolutionary approaches....

  1. Algorithmic Mechanism Design of Evolutionary Computation.

    Science.gov (United States)

    Pei, Yan

    2015-01-01

    We consider algorithmic design, enhancement, and improvement of evolutionary computation as a mechanism design problem. All individuals or several groups of individuals can be considered as self-interested agents. The individuals in evolutionary computation can manipulate parameter settings and operations by satisfying their own preferences, which are defined by an evolutionary computation algorithm designer, rather than by following a fixed algorithm rule. Evolutionary computation algorithm designers or self-adaptive methods should construct proper rules and mechanisms for all agents (individuals) to conduct their evolution behaviour correctly in order to definitely achieve the desired and preset objective(s). As a case study, we propose a formal framework on parameter setting, strategy selection, and algorithmic design of evolutionary computation by considering the Nash strategy equilibrium of a mechanism design in the search process. The evaluation results present the efficiency of the framework. This primary principle can be implemented in any evolutionary computation algorithm that needs to consider strategy selection issues in its optimization process. The final objective of our work is to solve evolutionary computation design as an algorithmic mechanism design problem and establish its fundamental aspect by taking this perspective. This paper is the first step towards achieving this objective by implementing a strategy equilibrium solution (such as Nash equilibrium) in evolutionary computation algorithm.

  2. Evolutionary principles and their practical application

    Science.gov (United States)

    Hendry, Andrew P; Kinnison, Michael T; Heino, Mikko; Day, Troy; Smith, Thomas B; Fitt, Gary; Bergstrom, Carl T; Oakeshott, John; Jørgensen, Peter S; Zalucki, Myron P; Gilchrist, George; Southerton, Simon; Sih, Andrew; Strauss, Sharon; Denison, Robert F; Carroll, Scott P

    2011-01-01

    Evolutionary principles are now routinely incorporated into medicine and agriculture. Examples include the design of treatments that slow the evolution of resistance by weeds, pests, and pathogens, and the design of breeding programs that maximize crop yield or quality. Evolutionary principles are also increasingly incorporated into conservation biology, natural resource management, and environmental science. Examples include the protection of small and isolated populations from inbreeding depression, the identification of key traits involved in adaptation to climate change, the design of harvesting regimes that minimize unwanted life-history evolution, and the setting of conservation priorities based on populations, species, or communities that harbor the greatest evolutionary diversity and potential. The adoption of evolutionary principles has proceeded somewhat independently in these different fields, even though the underlying fundamental concepts are the same. We explore these fundamental concepts under four main themes: variation, selection, connectivity, and eco-evolutionary dynamics. Within each theme, we present several key evolutionary principles and illustrate their use in addressing applied problems. We hope that the resulting primer of evolutionary concepts and their practical utility helps to advance a unified multidisciplinary field of applied evolutionary biology. PMID:25567966

  3. Evolutionary Biology in the Medical School Curriculum.

    Science.gov (United States)

    Neese, Randolph M.; Schiffman, Joshua D.

    2003-01-01

    Presents a study in which a questionnaire was given to deans at North American medical schools to determine which aspects of evolutionary biology are included in the curricula and the factors that influence this. Suggests that most future physicians should learn evolutionary biology as undergraduates if they are to learn it at all. (Author/NB)

  4. Handbook of differential equations evolutionary equations

    CERN Document Server

    Dafermos, CM

    2008-01-01

    The material collected in this volume discusses the present as well as expected future directions of development of the field with particular emphasis on applications. The seven survey articles present different topics in Evolutionary PDE's, written by leading experts.- Review of new results in the area- Continuation of previous volumes in the handbook series covering Evolutionary PDEs- Written by leading experts

  5. On the Evolutionary Stability of Bargaining Inefficiency

    DEFF Research Database (Denmark)

    Poulsen, Anders

    This paper investigates whether 'tough' bargaining behavior, which gives rise to inefficiency, can be evolutionary stable. We show that in a two-stage Nash Demand Game tough behavior survives. Indeed, almost all the surplus may be wasted. We also study the Ultimatum Game. Here evolutionary...

  6. Toward a unifying framework for evolutionary processes.

    Science.gov (United States)

    Paixão, Tiago; Badkobeh, Golnaz; Barton, Nick; Çörüş, Doğan; Dang, Duc-Cuong; Friedrich, Tobias; Lehre, Per Kristian; Sudholt, Dirk; Sutton, Andrew M; Trubenová, Barbora

    2015-10-21

    The theory of population genetics and evolutionary computation have been evolving separately for nearly 30 years. Many results have been independently obtained in both fields and many others are unique to its respective field. We aim to bridge this gap by developing a unifying framework for evolutionary processes that allows both evolutionary algorithms and population genetics models to be cast in the same formal framework. The framework we present here decomposes the evolutionary process into its several components in order to facilitate the identification of similarities between different models. In particular, we propose a classification of evolutionary operators based on the defining properties of the different components. We cast several commonly used operators from both fields into this common framework. Using this, we map different evolutionary and genetic algorithms to different evolutionary regimes and identify candidates with the most potential for the translation of results between the fields. This provides a unified description of evolutionary processes and represents a stepping stone towards new tools and results to both fields. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Democratizing evolutionary biology, lessons from insects

    DEFF Research Database (Denmark)

    Dunn, Robert Roberdeau; Beasley, DeAnna E.

    2016-01-01

    The engagement of the public in the scientific process is an old practice. Yet with recent advances in technology, the role of the citizen scientist in studying evolutionary processes has increased. Insects provide ideal models for understanding these evolutionary processes at large scales...

  8. Oversimplifying Evolutionary Psychology Leads to Explanatory Gaps

    Science.gov (United States)

    Tate, Chuck; Ledbetter, Jay N.

    2010-01-01

    Comments on Evolutionary psychology: Controversies, questions, prospects, and limitations by Confer et al. They argued that SST cannot explain the existence of either homosexuality or suicide within the human species. We contend that a sufficiently nuanced evolutionary position has no difficulties explaining either phenomenon. Also in this…

  9. Red wine polyphenolic compounds strongly inhibit pro-matrix metalloproteinase-2 expression and its activation in response to thrombin via direct inhibition of membrane type 1-matrix metalloproteinase in vascular smooth muscle cells.

    Science.gov (United States)

    Oak, Min-Ho; El Bedoui, Jasser; Anglard, Patrick; Schini-Kerth, Valérie B

    2004-09-28

    Regular consumption of moderate amounts of red wine is associated with a reduced risk of coronary disease. Matrix metalloproteinases (MMPs) that participate in extracellular matrix degradation have been involved in atherosclerotic plaque growth and instability. The present study examined whether red wine polyphenolic compounds (RWPCs) inhibit activation of MMP-2, a major gelatinase, in vascular smooth muscle cells (VSMCs). Expression of pro-MMP-2 was assessed by Western and Northern blot analyses; MMP-2 activity was assessed by zymography and cell invasion by a modified Boyden's chamber assay. High levels of pro-MMP-2 and low levels of MMP-2 activity were found in conditioned medium from unstimulated VSMCs. Thrombin induced cell-associated pro-MMP-2 protein expression and MMP-2 activity in conditioned medium of VSMCs. The stimulatory effect of thrombin on MMP-2 activation was prevented by RWPCs in a concentration-dependent and reversible manner. Thrombin markedly increased cell-associated membrane type 1 (MT1)-MMP activity, the physiological activator of pro-MMP-2, and this response was not affected by RWPCs. However, addition of RWPCs directly to MT1-MMP abolished its metalloproteinase activity in a reversible manner. Finally, matrix invasion of VSMCs was stimulated by thrombin, and this response was prevented by RWPCs as efficiently as a broad-spectrum MMP inhibitor. The present findings demonstrate that RWPCs effectively inhibit thrombin-induced matrix invasion of VSMCs, most likely by preventing the expression and activation of MMP-2 via direct inhibition of MT1-MMP activity. The inhibitory effect of RWPCs on the activation of pro-MMP-2 and matrix degradation might contribute to their beneficial effects on the cardiovascular system.

  10. Evolutionary dynamics of social dilemmas with asymmetry

    Science.gov (United States)

    Ma, Yongjuan; Chu, Chen; Chen, Fei; Shen, Chen; Geng, Yini; Shi, Lei

    2018-04-01

    Asymmetric phenomenon is ubiquitous in human and animal societies. Based on this fact, we construct an asymmetric way to investigate the evolution of cooperation. In detail, the structured populations are classified into two types: players of type A (strong player) possess higher fitness, while players of type B (weak player) possess fitness equaling their payoffs. Through numerical simulation, we find that our asymmetric setup can promote the evolution of cooperation, which is related to the leader role of the players of type A. It is worth mentioning that the larger the value of ω, namely, the degree of asymmetric becomes more large, the higher the level of cooperation. Besides, the higher degree of asymmetric will lead to a long relaxation time reaching stationary state and less striking promoting effect. Lastly, in order to test the robustness of mechanism, we explore the evolution of cooperation on different topologies.

  11. Evolutionary game dynamics in a growing structured population

    International Nuclear Information System (INIS)

    Poncela, Julia; Gomez-Gardenes, Jesus; Moreno, Yamir; Traulsen, Arne

    2009-01-01

    We discuss a model for evolutionary game dynamics in a growing, network-structured population. In our model, new players can either make connections to random preexisting players or preferentially attach to those that have been successful in the past. The latter depends on the dynamics of strategies in the game, which we implement following the so-called Fermi rule such that the limits of weak and strong strategy selection can be explored. Our framework allows to address general evolutionary games. With only two parameters describing the preferential attachment and the intensity of selection, we describe a wide range of network structures and evolutionary scenarios. Our results show that even for moderate payoff preferential attachment, over represented hubs arise. Interestingly, we find that while the networks are growing, high levels of cooperation are attained, but the same network structure does not promote cooperation as a static network. Therefore, the mechanism of payoff preferential attachment is different to those usually invoked to explain the promotion of cooperation in static, already-grown networks.

  12. Evolutionary game theory using agent-based methods.

    Science.gov (United States)

    Adami, Christoph; Schossau, Jory; Hintze, Arend

    2016-12-01

    Evolutionary game theory is a successful mathematical framework geared towards understanding the selective pressures that affect the evolution of the strategies of agents engaged in interactions with potential conflicts. While a mathematical treatment of the costs and benefits of decisions can predict the optimal strategy in simple settings, more realistic settings such as finite populations, non-vanishing mutations rates, stochastic decisions, communication between agents, and spatial interactions, require agent-based methods where each agent is modeled as an individual, carries its own genes that determine its decisions, and where the evolutionary outcome can only be ascertained by evolving the population of agents forward in time. While highlighting standard mathematical results, we compare those to agent-based methods that can go beyond the limitations of equations and simulate the complexity of heterogeneous populations and an ever-changing set of interactors. We conclude that agent-based methods can predict evolutionary outcomes where purely mathematical treatments cannot tread (for example in the weak selection-strong mutation limit), but that mathematics is crucial to validate the computational simulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Evolutionary Effect on the Embodied Beauty of Landscape Architectures.

    Science.gov (United States)

    Zhang, Wei; Tang, Xiaoxiang; He, Xianyou; Chen, Guangyao

    2018-01-01

    According to the framework of evolutionary aesthetics, a sense of beauty is related to environmental adaptation and plasticity of human beings, which has adaptive value and biological foundations. Prior studies have demonstrated that organisms derive benefits from the landscape. In this study, we investigated whether the benefits of landscape might elicit a stronger sense of beauty and what the nature of this sense of beauty is. In two experiments, when viewing classical landscape and nonlandscape architectures photographs, participants rated the aesthetic scores (Experiment 1) and had a two-alternative forced choice aesthetic judgment by pressing the reaction button located near to (15 cm) or far from (45 cm) the presenting stimuli (Experiment 2). The results showed that reaction of aesthetic ratings for classical landscape architectures was faster than those of classical nonlandscape architectures. Furthermore, only the reaction of beautiful judgment of classical landscape architecture photograph was significantly faster when the reaction button was in the near position to the presenting photograph than those in the position of far away from the presenting photograph. This finding suggests a facilitated effect for the aesthetic perception of classical landscape architectures due to their corresponding components including water and green plants with strong evolutionary implications. Furthermore, this sense of beauty for classical landscape architectures might be the embodied approach to beauty based on the viewpoint of evolutionary aesthetics and embodied cognition.

  14. Titanium: light, strong, and white

    Science.gov (United States)

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  15. The Evolutionary Basis of Naturally Diverse Rice Leaves Anatomy.

    Directory of Open Access Journals (Sweden)

    Jolly Chatterjee

    Full Text Available Rice contains genetically and ecologically diverse wild and cultivated species that show a wide variation in plant and leaf architecture. A systematic characterization of leaf anatomy is essential in understanding the dynamics behind such diversity. Therefore, leaf anatomies of 24 Oryza species spanning 11 genetically diverse rice genomes were studied in both lateral and longitudinal directions and possible evolutionary trends were examined. A significant inter-species variation in mesophyll cells, bundle sheath cells, and vein structure was observed, suggesting precise genetic control over these major rice leaf anatomical traits. Cellular dimensions, measured along three growth axes, were further combined proportionately to construct three-dimensional (3D leaf anatomy models to compare the relative size and orientation of the major cell types present in a fully expanded leaf. A reconstruction of the ancestral leaf state revealed that the following are the major characteristics of recently evolved rice species: fewer veins, larger and laterally elongated mesophyll cells, with an increase in total mesophyll area and in bundle sheath cell number. A huge diversity in leaf anatomy within wild and domesticated rice species has been portrayed in this study, on an evolutionary context, predicting a two-pronged evolutionary pathway leading to the 'sativa leaf type' that we see today in domesticated species.

  16. Inflated impact factors? The true impact of evolutionary papers in non-evolutionary journals.

    Directory of Open Access Journals (Sweden)

    Erik Postma

    Full Text Available Amongst the numerous problems associated with the use of impact factors as a measure of quality are the systematic differences in impact factors that exist among scientific fields. While in theory this can be circumvented by limiting comparisons to journals within the same field, for a diverse and multidisciplinary field like evolutionary biology, in which the majority of papers are published in journals that publish both evolutionary and non-evolutionary papers, this is impossible. However, a journal's overall impact factor may well be a poor predictor for the impact of its evolutionary papers. The extremely high impact factors of some multidisciplinary journals, for example, are by many believed to be driven mostly by publications from other fields. Despite plenty of speculation, however, we know as yet very little about the true impact of evolutionary papers in journals not specifically classified as evolutionary. Here I present, for a wide range of journals, an analysis of the number of evolutionary papers they publish and their average impact. I show that there are large differences in impact among evolutionary and non-evolutionary papers within journals; while the impact of evolutionary papers published in multidisciplinary journals is substantially overestimated by their overall impact factor, the impact of evolutionary papers in many of the more specialized, non-evolutionary journals is significantly underestimated. This suggests that, for evolutionary biologists, publishing in high-impact multidisciplinary journals should not receive as much weight as it does now, while evolutionary papers in more narrowly defined journals are currently undervalued. Importantly, however, their ranking remains largely unaffected. While journal impact factors may thus indeed provide a meaningful qualitative measure of impact, a fair quantitative comparison requires a more sophisticated journal classification system, together with multiple field

  17. Global loss of avian evolutionary uniqueness in urban areas.

    Science.gov (United States)

    Ibáñez-Álamo, Juan Diego; Rubio, Enrique; Benedetti, Yanina; Morelli, Federico

    2017-08-01

    Urbanization, one of the most important anthropogenic impacts on Earth, is rapidly expanding worldwide. This expansion of urban land-covered areas is known to significantly reduce different components of biodiversity. However, the global evidence for this effect is mainly focused on a single diversity measure (species richness) with a few local or regional studies also supporting reductions in functional diversity. We have used birds, an important ecological group that has been used as surrogate for other animals, to investigate the hypothesis that urbanization reduces the global taxonomical and/or evolutionary diversity. We have also explored whether there is evidence supporting that urban bird communities are evolutionarily homogenized worldwide in comparison with nonurban ones by means of using evolutionary distinctiveness (how unique are the species) of bird communities. To our knowledge, this is the first attempt to quantify the effect of urbanization in more than one single diversity measure as well as the first time to look for associations between urbanization and phylogenetic diversity at a large spatial scale. Our findings show a strong and globally consistent reduction in taxonomic diversity in urban areas, which is also synchronized with the evolutionary homogenization of urban bird communities. Despite our general patterns, we found some regional differences in the intensity of the effect of cities on bird species richness or evolutionary distinctiveness, suggesting that conservation efforts should be adapted locally. Our findings might be useful for conservationists and policymakers to minimize the impact of urban development on Earth's biodiversity and help design more realistic conservation strategies. © 2016 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

  18. On the evolution of misunderstandings about evolutionary psychology.

    Science.gov (United States)

    Young, J; Persell, R

    2000-04-01

    Some of the controversy surrounding evolutionary explanations of human behavior may be due to cognitive information-processing patterns that are themselves the result of evolutionary processes. Two such patterns are (1) the tendency to oversimplify information so as to reduce demand on cognitive resources and (2) our strong desire to generate predictability and stability from perceptions of the external world. For example, research on social stereotyping has found that people tend to focus automatically on simplified social-categorical information, to use such information when deciding how to behave, and to rely on such information even in the face of contradictory evidence. Similarly, an undying debate over nature vs. nurture is shaped by various data-reduction strategies that frequently oversimplify, and thus distort, the intent of the supporting arguments. This debate is also often marked by an assumption that either the nature or the nurture domain may be justifiably excluded at an explanatory level because one domain appears to operate in a sufficiently stable and predictable way for a particular argument. As a result, critiques in-veighed against evolutionary explanations of behavior often incorporate simplified--and erroneous--assumptions about either the mechanics of how evolution operates or the inevitable implications of evolution for understanding human behavior. The influences of these tendencies are applied to a discussion of the heritability of behavioral characteristics. It is suggested that the common view that Mendelian genetics can explain the heritability of complex behaviors, with a one-gene-one-trait process, is misguided. Complex behaviors are undoubtedly a product of a more complex interaction between genes and environment, ensuring that both nature and nurture must be accommodated in a yet-to-be-developed post-Mendelian model of genetic influence. As a result, current public perceptions of evolutionary explanations of behavior are

  19. Evolutionary dynamics from a variational principle

    Science.gov (United States)

    Klimek, Peter; Thurner, Stefan; Hanel, Rudolf

    2010-07-01

    We demonstrate with a thought experiment that fitness-based population dynamical approaches to evolution are not able to make quantitative, falsifiable predictions about the long-term behavior of some evolutionary systems. A key characteristic of evolutionary systems is the ongoing endogenous production of new species. These novel entities change the conditions for already existing species. Even Darwin’s Demon, a hypothetical entity with exact knowledge of the abundance of all species and their fitness functions at a given time, could not prestate the impact of these novelties on established populations. We argue that fitness is always a posteriori knowledge—it measures but does not explain why a species has reproductive success or not. To overcome these conceptual limitations, a variational principle is proposed in a spin-model-like setup of evolutionary systems. We derive a functional which is minimized under the most general evolutionary formulation of a dynamical system, i.e., evolutionary trajectories causally emerge as a minimization of a functional. This functional allows the derivation of analytic solutions of the asymptotic diversity for stochastic evolutionary systems within a mean-field approximation. We test these approximations by numerical simulations of the corresponding model and find good agreement in the position of phase transitions in diversity curves. The model is further able to reproduce stylized facts of timeseries from several man-made and natural evolutionary systems. Light will be thrown on how species and their fitness landscapes dynamically coevolve.

  20. Evolutionary psychology. Controversies, questions, prospects, and limitations.

    Science.gov (United States)

    Confer, Jaime C; Easton, Judith A; Fleischman, Diana S; Goetz, Cari D; Lewis, David M G; Perilloux, Carin; Buss, David M

    2010-01-01

    Evolutionary psychology has emerged over the past 15 years as a major theoretical perspective, generating an increasing volume of empirical studies and assuming a larger presence within psychological science. At the same time, it has generated critiques and remains controversial among some psychologists. Some of the controversy stems from hypotheses that go against traditional psychological theories; some from empirical findings that may have disturbing implications; some from misunderstandings about the logic of evolutionary psychology; and some from reasonable scientific concerns about its underlying framework. This article identifies some of the most common concerns and attempts to elucidate evolutionary psychology's stance pertaining to them. These include issues of testability and falsifiability; the domain specificity versus domain generality of psychological mechanisms; the role of novel environments as they interact with evolved psychological circuits; the role of genes in the conceptual structure of evolutionary psychology; the roles of learning, socialization, and culture in evolutionary psychology; and the practical value of applied evolutionary psychology. The article concludes with a discussion of the limitations of current evolutionary psychology. 2009 APA, all rights reserved.

  1. Phylogenetic inference with weighted codon evolutionary distances.

    Science.gov (United States)

    Criscuolo, Alexis; Michel, Christian J

    2009-04-01

    We develop a new approach to estimate a matrix of pairwise evolutionary distances from a codon-based alignment based on a codon evolutionary model. The method first computes a standard distance matrix for each of the three codon positions. Then these three distance matrices are weighted according to an estimate of the global evolutionary rate of each codon position and averaged into a unique distance matrix. Using a large set of both real and simulated codon-based alignments of nucleotide sequences, we show that this approach leads to distance matrices that have a significantly better treelikeness compared to those obtained by standard nucleotide evolutionary distances. We also propose an alternative weighting to eliminate the part of the noise often associated with some codon positions, particularly the third position, which is known to induce a fast evolutionary rate. Simulation results show that fast distance-based tree reconstruction algorithms on distance matrices based on this codon position weighting can lead to phylogenetic trees that are at least as accurate as, if not better, than those inferred by maximum likelihood. Finally, a well-known multigene dataset composed of eight yeast species and 106 codon-based alignments is reanalyzed and shows that our codon evolutionary distances allow building a phylogenetic tree which is similar to those obtained by non-distance-based methods (e.g., maximum parsimony and maximum likelihood) and also significantly improved compared to standard nucleotide evolutionary distance estimates.

  2. Evolutionary approaches to understanding sleep.

    Science.gov (United States)

    Lee Kavanau, J

    2005-04-01

    A major controversy over REM sleep's role in memory processing may owe to inadequate allowances for the highly conservative nature of evolutionary adaptations. The controversy hinges on whether NREM sleep, alone, retains primitive memory processing capabilities. The selective pressure for primitive sleep, is thought to have been the need to obviate conflicts between enormous neural processing requirements of complex visual analysis and split-second control of movements, on the one hand, and memory processing, on the other. The most efficient memory processing during mammalian and avian sleep appears to be a two-step process: synapses in individual component circuits of events are reinforced primarily by slow brain waves during NREM sleep, with the reinforced components temporally bound by fast waves, and manifested as dreams, during REM sleep. This dual action could account for partitioning of sleep periods into multiple NREM-REM cycles. It is proposed that in the absence of REM sleep, all needed memory processing can be accomplished by NREM sleep, alone, though less efficiently. Many symptoms of fatal familial insomnia are attributed to subnormal nightly reinforcement of brain circuitry because of almost total loss of sleep, and compensatory responses thereto during waking. During this disorder, sensory circuitry seemingly is spared by virtue of its supernormal reinforcement during almost continuous waking. Contrariwise, sparing of an adult's 'higher faculties' in encephalitis lethargica appears to owe to supernormal circuit reinforcement during almost continuous sleep.

  3. Evolutionary dynamics under interactive diversity

    Science.gov (United States)

    Su, Qi; Li, Aming; Wang, Long

    2017-10-01

    As evidenced by many cases in human societies, individuals often make different behavior decisions in different interactions, and adaptively adjust their behavior in changeable interactive scenarios. However, up to now, how such diverse interactive behavior affects cooperation dynamics has still remained unknown. Here we develop a general framework of interactive diversity, which models individuals’ separated behavior against distinct opponents and their adaptive adjustment in response to opponents’ strategies, to explore the evolution of cooperation. We find that interactive diversity enables individuals to reciprocate every single opponent, and thus sustains large-scale reciprocal interactions. Our work witnesses an impressive boost of cooperation for a notably extensive range of parameters and for all pairwise games. These results are robust against well-mixed and various networked populations, and against degree-normalized and cumulative payoff patterns. From the perspective of network dynamics, distinguished from individuals competing for nodes in most previous work, in this paper, the system evolves in the form of behavior disseminating along edges. We propose a theoretical method based on evolution of edges, which predicts well both the frequency of cooperation and the compact cooperation clusters. Our thorough investigation clarifies the positive role of interactive diversity in resolving social dilemmas and highlights the significance of understanding evolutionary dynamics from the viewpoint of edge dynamics.

  4. The Evolutionary Origins of Hierarchy.

    Directory of Open Access Journals (Sweden)

    Henok Mengistu

    2016-06-01

    Full Text Available Hierarchical organization-the recursive composition of sub-modules-is ubiquitous in biological networks, including neural, metabolic, ecological, and genetic regulatory networks, and in human-made systems, such as large organizations and the Internet. To date, most research on hierarchy in networks has been limited to quantifying this property. However, an open, important question in evolutionary biology is why hierarchical organization evolves in the first place. It has recently been shown that modularity evolves because of the presence of a cost for network connections. Here we investigate whether such connection costs also tend to cause a hierarchical organization of such modules. In computational simulations, we find that networks without a connection cost do not evolve to be hierarchical, even when the task has a hierarchical structure. However, with a connection cost, networks evolve to be both modular and hierarchical, and these networks exhibit higher overall performance and evolvability (i.e. faster adaptation to new environments. Additional analyses confirm that hierarchy independently improves adaptability after controlling for modularity. Overall, our results suggest that the same force-the cost of connections-promotes the evolution of both hierarchy and modularity, and that these properties are important drivers of network performance and adaptability. In addition to shedding light on the emergence of hierarchy across the many domains in which it appears, these findings will also accelerate future research into evolving more complex, intelligent computational brains in the fields of artificial intelligence and robotics.

  5. Flourishing: An Evolutionary Concept Analysis.

    Science.gov (United States)

    Agenor, Christine; Conner, Norma; Aroian, Karen

    2017-11-01

    Mental health is an important measure of public health (WHO, 2004); however, nursing practice and research continues to prioritize mental illness, rather than well-being (Wand, 2011). Flourishing is a recent concept in the field of well-being. The term has been used sparingly in nursing practice and research, and conceptual clarification is needed to promote comprehensive understanding of the phenomenon. The purpose of this study is to critically analyze flourishing, assess the maturity of the concept, and provide recommendations for future research, education, and practice. The concept of flourishing was analyzed using the evolutionary approach to concept analysis (Rodgers, 2000). A search for articles on flourishing within the context of well-being was conducted through CINAHL, MEDLINE, and PsycINFO. A sample of 32 articles and 1 book was reviewed. Data were reviewed for concept attributes, antecedents, consequences, surrogate terms and related concepts. Four models of flourishing were identified with six overlapping attributes: meaning, positive relationships, engagement, competence, positive emotion, and self-esteem. Limited longitudinal and predictive studies have been conducted, but there is evidence for several antecedents and outcomes of flourishing. Research is ongoing primarily in psychology and sociology and is lacking in other disciplines. The concept of flourishing is immature; however, evidence is building for related concepts. A lack of consistent terminology regarding flourishing prevents knowledge development of flourishing as a distinct concept. Further multidisciplinary research is needed to establish standard operational and conceptual definitions and develop effective interventions.

  6. Evolutionary optimization of protein folding.

    Directory of Open Access Journals (Sweden)

    Cédric Debès

    Full Text Available Nature has shaped the make up of proteins since their appearance, [Formula: see text]3.8 billion years ago. However, the fundamental drivers of structural change responsible for the extraordinary diversity of proteins have yet to be elucidated. Here we explore if protein evolution affects folding speed. We estimated folding times for the present-day catalog of protein domains directly from their size-modified contact order. These values were mapped onto an evolutionary timeline of domain appearance derived from a phylogenomic analysis of protein domains in 989 fully-sequenced genomes. Our results show a clear overall increase of folding speed during evolution, with known ultra-fast downhill folders appearing rather late in the timeline. Remarkably, folding optimization depends on secondary structure. While alpha-folds showed a tendency to fold faster throughout evolution, beta-folds exhibited a trend of folding time increase during the last [Formula: see text]1.5 billion years that began during the "big bang" of domain combinations. As a consequence, these domain structures are on average slow folders today. Our results suggest that fast and efficient folding of domains shaped the universe of protein structure. This finding supports the hypothesis that optimization of the kinetic and thermodynamic accessibility of the native fold reduces protein aggregation propensities that hamper cellular functions.

  7. On the Runtime of Randomized Local Search and Simple Evolutionary Algorithms for Dynamic Makespan Scheduling

    DEFF Research Database (Denmark)

    Neumann, Frank; Witt, Carsten

    2015-01-01

    combinatorial optimization problem, namely makespan scheduling. We study the model of a strong adversary which is allowed to change one job at regular intervals. Furthermore, we investigate the setting of random changes. Our results show that randomized local search and a simple evolutionary algorithm are very...

  8. Evolutionary theory and the naturalist fallacy

    DEFF Research Database (Denmark)

    Grodal, Torben Kragh

    2008-01-01

    The article is an invited response to a target article by Joseph Carroll entitled "An evolutionary paradigm for literary study". It argues that the target article  misuse the fact that works of art are based on adaptations that were fitness-enhancing in the era of evolutionary adaptations to claim...... that great work of art are also automatically fitness-enhancing in the present day environment, at that there are simple correllations between whether a work of art has a high aesthetic value and whether it is fitness-enhancing or not.  Keywords :  Evolutionary aesthetics, film theory, literary theory...

  9. Evolutionary theory and the naturalist fallacy

    DEFF Research Database (Denmark)

    Grodal, Torben Kragh

    2008-01-01

    that great work of art are also automatically fitness-enhancing in the present day environment, at that there are simple correllations between whether a work of art has a high aesthetic value and whether it is fitness-enhancing or not.  Keywords :  Evolutionary aesthetics, film theory, literary theory......The article is an invited response to a target article by Joseph Carroll entitled "An evolutionary paradigm for literary study". It argues that the target article  misuse the fact that works of art are based on adaptations that were fitness-enhancing in the era of evolutionary adaptations to claim...

  10. Physical Inactivity, Obesity, and Type 2 Diabetes: An Evolutionary Perspective

    Science.gov (United States)

    Eaton, S. Boyd; Eaton, Stanley B.

    2017-01-01

    Physical inactivity (and unhealthy nutrition) has distorted body composition and, in turn, reordered the proportions of myocyte and adipocyte insulin receptors. Insulin acting on adipocyte receptors produces less glucose uptake than does comparable interaction with myocyte receptors. Accordingly, in individuals with disproportionate muscle/fat…

  11. Strong coupling phase in QED

    International Nuclear Information System (INIS)

    Aoki, Ken-ichi

    1988-01-01

    Existence of a strong coupling phase in QED has been suggested in solutions of the Schwinger-Dyson equation and in Monte Carlo simulation of lattice QED. In this article we recapitulate the previous arguments, and formulate the problem in the modern framework of the renormalization theory, Wilsonian renormalization. This scheme of renormalization gives the best understanding of the basic structure of a field theory especially when it has a multi-phase structure. We resolve some misleading arguments in the previous literature. Then we set up a strategy to attack the strong phase, if any. We describe a trial; a coupled Schwinger-Dyson equation. Possible picture of the strong coupling phase QED is presented. (author)

  12. [Evolutionary Concept Analysis of Spirituality].

    Science.gov (United States)

    Ko, Il Sun; Choi, So Young; Kim, Jin Sook

    2017-04-01

    This study was done to clarify attributes, antecedents, and consequences of spirituality. Rodgers's evolutionary concept analysis was used to analyze fifty seven studies from the literature related to spirituality as it appears in systematic literature reviews of theology, medicine, counseling & psychology, social welfare, and nursing. Spirituality was found to consist of two dimensions and eight attributes: 1) vertical dimension: 'intimacy and connectedness with God' and 'holy life and belief', 2) horizontal dimension: 'self-transcendence', 'meaning and purpose in life', 'self-integration', and 'self-creativity' in relationship with self, 'connectedness' and 'trust' in relationship with others·neighbors·nature. Antecedents of spirituality were socio-demographic, religious, psychological, and health related characteristics. Consequences of spirituality were positive and negative. Being positive included 'life centered on God' in vertical dimension, and among horizontal dimension 'joy', 'hope', 'wellness', 'inner peace', and 'self-actualization' in relationship with self, 'doing in love' and 'extended life toward neighbors and the world' in relationship with others·neighbors·nature. Being negative was defined as having 'guilt', 'inner conflict', 'loneliness', and 'spiritual distress'. Facilitators of spirituality were stressful life events and experiences. Spirituality is a multidimensional concept. Unchangeable attributes of spirituality are 'connectedness with God', 'self-transcendence', 'meaning of life' and 'connectedness with others·nature'. Unchangeable consequences of spirituality are 'joy' and 'hope'. The findings suggest that the dimensional framework of spirituality can be used to assess the current spiritual state of patients. Based on these results, the development of a Korean version of the scale measuring spirituality is recommended. © 2017 Korean Society of Nursing Science

  13. Evolutionary biology and life histories

    Directory of Open Access Journals (Sweden)

    Brown, C. R.

    2004-06-01

    Full Text Available The demographic processes that drive the spread of populations through environments and in turn determine the abundance of organisms are the same demographic processes that drive the spread of genes through populations and in turn determine gene frequencies and fitness. Conceptually, marked similarities exist in the dynamic processes underlying population ecology and those underlying evolutionary biology. Central to an understanding of both disciplines is life history and its component demographic rates, such as survival, fecundity, and age of first breeding, and biologists from both fields have a vested interest in good analytical machinery for the estimation and analysis of these demographic rates. In the EURING conferences, we have been striving since the mid 1980s to promote a quantitative understanding of demographic rates through interdisciplinary collaboration between ecologists and statisticians. From the ecological side, the principal impetus has come from population biology, and in particular from wildlife biology, but the importance of good quantitative insights into demographic processes has long been recognized by a number of evolutionary biologists (e.g., Nichols & Kendall, 1995; Clobert, 1995; Cooch et al., 2002. In organizing this session, we have aimed to create a forum for those committed to gaining the best possible understanding of evolutionary processes through the application of modern quantitative methods for the collection and interpretation of data on marked animal populations. Here we present a short overview of the material presented in the session on evolutionary biology and life histories. In a plenary talk, Brown & Brown (2004 explored how mark–recapture methods have allowed a better understanding of the evolution of group–living and alternative reproductive tactics in colonial cliff swallows (Petrochelidon pyrrhonota. By estimating the number of transient birds passing through colonies of different sizes, they

  14. The Stochastic Evolutionary Game for a Population of Biological Networks Under Natural Selection

    Science.gov (United States)

    Chen, Bor-Sen; Ho, Shih-Ju

    2014-01-01

    In this study, a population of evolutionary biological networks is described by a stochastic dynamic system with intrinsic random parameter fluctuations due to genetic variations and external disturbances caused by environmental changes in the evolutionary process. Since information on environmental changes is unavailable and their occurrence is unpredictable, they can be considered as a game player with the potential to destroy phenotypic stability. The biological network needs to develop an evolutionary strategy to improve phenotypic stability as much as possible, so it can be considered as another game player in the evolutionary process, ie, a stochastic Nash game of minimizing the maximum network evolution level caused by the worst environmental disturbances. Based on the nonlinear stochastic evolutionary game strategy, we find that some genetic variations can be used in natural selection to construct negative feedback loops, efficiently improving network robustness. This provides larger genetic robustness as a buffer against neutral genetic variations, as well as larger environmental robustness to resist environmental disturbances and maintain a network phenotypic traits in the evolutionary process. In this situation, the robust phenotypic traits of stochastic biological networks can be more frequently selected by natural selection in evolution. However, if the harbored neutral genetic variations are accumulated to a sufficiently large degree, and environmental disturbances are strong enough that the network robustness can no longer confer enough genetic robustness and environmental robustness, then the phenotype robustness might break down. In this case, a network phenotypic trait may be pushed from one equilibrium point to another, changing the phenotypic trait and starting a new phase of network evolution through the hidden neutral genetic variations harbored in network robustness by adaptive evolution. Further, the proposed evolutionary game is extended to

  15. [Evolutionary medicine: an emergent basic science].

    Science.gov (United States)

    Spotorno, Angel E

    2005-02-01

    Evolutionary Medicine is an emergent basic science that offers new and varied perspectives to the comprehension of human health. The application of classic evolutionary theories (descent with modification, and natural selection) to the human organism, to its pathogens, and their mutual co-evolution, provides new explanations about why we get sick, how we can prevent this, and how we can heal. Medicine has focused mainly on the proximate or immediate causes of diseases and the treatment of symptoms, and very little on its evolutionary or mediate causes. For instance, the present human genome and phenotypes are essentially paleolithic ones: they are not adapted to modern life style, thus favoring the so-called diseases of civilization (ie: ateroesclerosis, senescence, myopia, phobias, panic attacks, stress, reproductive cancers). With the evolutionary approach, post-modern medicine is detecting better the vulnerabilities, restrictions, biases, adaptations and maladaptations of human body, its actual diseases, and its preventions.

  16. Evolutionary algorithms for mobile ad hoc networks

    CERN Document Server

    Dorronsoro, Bernabé; Danoy, Grégoire; Pigné, Yoann; Bouvry, Pascal

    2014-01-01

    Describes how evolutionary algorithms (EAs) can be used to identify, model, and minimize day-to-day problems that arise for researchers in optimization and mobile networking. Mobile ad hoc networks (MANETs), vehicular networks (VANETs), sensor networks (SNs), and hybrid networks—each of these require a designer’s keen sense and knowledge of evolutionary algorithms in order to help with the common issues that plague professionals involved in optimization and mobile networking. This book introduces readers to both mobile ad hoc networks and evolutionary algorithms, presenting basic concepts as well as detailed descriptions of each. It demonstrates how metaheuristics and evolutionary algorithms (EAs) can be used to help provide low-cost operations in the optimization process—allowing designers to put some “intelligence” or sophistication into the design. It also offers efficient and accurate information on dissemination algorithms topology management, and mobility models to address challenges in the ...

  17. Mean-Potential Law in Evolutionary Games

    Science.gov (United States)

    Nałecz-Jawecki, Paweł; Miekisz, Jacek

    2018-01-01

    The Letter presents a novel way to connect random walks, stochastic differential equations, and evolutionary game theory. We introduce a new concept of a potential function for discrete-space stochastic systems. It is based on a correspondence between one-dimensional stochastic differential equations and random walks, which may be exact not only in the continuous limit but also in finite-state spaces. Our method is useful for computation of fixation probabilities in discrete stochastic dynamical systems with two absorbing states. We apply it to evolutionary games, formulating two simple and intuitive criteria for evolutionary stability of pure Nash equilibria in finite populations. In particular, we show that the 1 /3 law of evolutionary games, introduced by Nowak et al. [Nature, 2004], follows from a more general mean-potential law.

  18. Evolutionary medicine: its scope, interest and potential

    Science.gov (United States)

    Stearns, Stephen C.

    2012-01-01

    This review is aimed at readers seeking an introductory overview, teaching courses and interested in visionary ideas. It first describes the range of topics covered by evolutionary medicine, which include human genetic variation, mismatches to modernity, reproductive medicine, degenerative disease, host–pathogen interactions and insights from comparisons with other species. It then discusses priorities for translational research, basic research and health management. Its conclusions are that evolutionary thinking should not displace other approaches to medical science, such as molecular medicine and cell and developmental biology, but that evolutionary insights can combine with and complement established approaches to reduce suffering and save lives. Because we are on the cusp of so much new research and innovative insights, it is hard to estimate how much impact evolutionary thinking will have on medicine, but it is already clear that its potential is enormous. PMID:22933370

  19. The active evolutionary lives of echinoderm larvae.

    Science.gov (United States)

    Raff, R A; Byrne, M

    2006-09-01

    Echinoderms represent a researchable subset of a dynamic larval evolutionary cosmos. Evolution of echinoderm larvae has taken place over widely varying time scales from the origins of larvae of living classes in the early Palaeozoic, approximately 500 million years ago, to recent, rapid and large-scale changes that have occurred within living genera within a span of less than a million years to a few million years. It is these recent evolutionary events that offer a window into processes of larval evolution operating at a micro-evolutionary level of evolution of discrete developmental mechanisms. We review the evolution of the diverse larval forms of living echinoderms to outline the origins of echinoderm larval forms, their diversity among living echinoderms, molecular clocks and rates of larval evolution, and finally current studies on the roles of developmental regulatory mechanisms in the rapid and radical evolutionary changes observed between closely related congeneric species.

  20. A Philosophical Perspective on Evolutionary Systems Biology.

    Science.gov (United States)

    O'Malley, Maureen A; Soyer, Orkun S; Siegal, Mark L

    2015-03-01

    Evolutionary systems biology (ESB) is an emerging hybrid approach that integrates methods, models, and data from evolutionary and systems biology. Drawing on themes that arose at a cross-disciplinary meeting on ESB in 2013, we discuss in detail some of the explanatory friction that arises in the interaction between evolutionary and systems biology. These tensions appear because of different modeling approaches, diverse explanatory aims and strategies, and divergent views about the scope of the evolutionary synthesis. We locate these discussions in the context of long-running philosophical deliberations on explanation, modeling, and theoretical synthesis. We show how many of the issues central to ESB's progress can be understood as general philosophical problems. The benefits of addressing these philosophical issues feed back into philosophy too, because ESB provides excellent examples of scientific practice for the development of philosophy of science and philosophy of biology.

  1. Evolutionary optimization of production materials workflow processes

    DEFF Research Database (Denmark)

    Herbert, Luke Thomas; Hansen, Zaza Nadja Lee; Jacobsen, Peter

    2014-01-01

    We present an evolutionary optimisation technique for stochastic production processes, which is able to find improved production materials workflow processes with respect to arbitrary combinations of numerical quantities associated with the production process. Working from a core fragment...

  2. Litter feedbacks, evolutionary change and exotic plant

    NARCIS (Netherlands)

    Eppinga, M.B.; Kaproth, M.A.; Collins, A.R.; Molofsky, J.

    2011-01-01

    1. Understanding the mechanisms driving exotic plant invasions is important for designing successful invader control strategies. Previous studies have highlighted different invasion mechanisms, including alteration of nutrient cycles through plant–soil feedback and evolutionary change toward more

  3. A Hybrid Chaotic Quantum Evolutionary Algorithm

    DEFF Research Database (Denmark)

    Cai, Y.; Zhang, M.; Cai, H.

    2010-01-01

    and enhance the global search ability. A large number of tests show that the proposed algorithm has higher convergence speed and better optimizing ability than quantum evolutionary algorithm, real-coded quantum evolutionary algorithm and hybrid quantum genetic algorithm. Tests also show that when chaos......A hybrid chaotic quantum evolutionary algorithm is proposed to reduce amount of computation, speed up convergence and restrain premature phenomena of quantum evolutionary algorithm. The proposed algorithm adopts the chaotic initialization method to generate initial population which will form...... a perfect distribution in feasible solution space in advantage of randomicity and non-repetitive ergodicity of chaos, the simple quantum rotation gate to update non-optimal individuals of population to reduce amount of computation, and the hybrid chaotic search strategy to speed up its convergence...

  4. Deciphering morphology in Triatominae: the evolutionary signals.

    Science.gov (United States)

    Dujardin, J P; Costa, J; Bustamante, D; Jaramillo, N; Catalá, S

    2009-01-01

    Many species of Triatominae show evidence for morphological plasticity. Frequent taxonomic questions arose from this variability leading to disputes about describing new subspecies, species or even genera. We suggest this phenotypic flexibility is primarily an intraspecific feature, but with potential for evolutionary changes. We present arguments for a selection regime leading to the separation of species having low developmental canalization into morphologically distinct ecotypes. We suggest that these ecotypes, or morphs, or forms, may have evolutionary importance even if gene flow still exists between them. Thus, although we consider the morphological plasticity of Triatominae as an intraspecific trait, we defend the idea that it might represent a common evolutionary route to new species. Speciation processes in Triatominae could result from disruptive selection regimes combined with weak developmental canalization. Added to this basic pattern, accidental events could hasten evolutionary change. We suggest the heterosis as one of them.

  5. Evolutionary and mechanistic theories of aging.

    Science.gov (United States)

    Hughes, Kimberly A; Reynolds, Rose M

    2005-01-01

    Senescence (aging) is defined as a decline in performance and fitness with advancing age. Senescence is a nearly universal feature of multicellular organisms, and understanding why it occurs is a long-standing problem in biology. Here we present a concise review of both evolutionary and mechanistic theories of aging. We describe the development of the general evolutionary theory, along with the mutation accumulation, antagonistic pleiotropy, and disposable soma versions of the evolutionary model. The review of the mechanistic theories focuses on the oxidative stress resistance, cellular signaling, and dietary control mechanisms of life span extension. We close with a discussion of how an approach that makes use of both evolutionary and molecular analyses can address a critical question: Which of the mechanisms that can cause variation in aging actually do cause variation in natural populations?

  6. Evolutionary Robotics: What, Why, and Where to

    Directory of Open Access Journals (Sweden)

    Stephane eDoncieux

    2015-03-01

    Full Text Available Evolutionary robotics applies the selection, variation, and heredity principles of natural evolution to the design of robots with embodied intelligence. It can be considered as a subfield of robotics that aims to create more robust and adaptive robots. A pivotal feature of the evolutionary approach is that it considers the whole robot at once, and enables the exploitation of robot features in a holistic manner. Evolutionary robotics can also be seen as an innovative approach to the study of evolution based on a new kind of experimentalism. The use of robots as a substrate can help address questions that are difficult, if not impossible, to investigate through computer simulations or biological studies. In this paper we consider the main achievements of evolutionary robotics, focusing particularly on its contributions to both engineering and biology. We briefly elaborate on methodological issues, review some of the most interesting findings, and discuss important open issues and promising avenues for future work.

  7. Endogenous money: the evolutionary versus revolutionary views

    OpenAIRE

    Louis-Philippe Rochon; Sergio Rossi

    2013-01-01

    The purpose of this paper is to shed light on the endogenous nature of money. Contrary to the established post-Keynesian, or evolutionary, view, this paper argues that money has always been endogenous, irrespective of the historical period. Instead of the evolutionary theory of money and banking that can be traced back to Chick (1986), this paper puts forward a revolutionary definition of endogenous money consistent with many aspects of post-Keynesian economics as well as with the monetary ci...

  8. Predicting virus emergence amid evolutionary noise

    OpenAIRE

    Geoghegan, Jemma L.; Holmes, Edward C.

    2017-01-01

    The study of virus disease emergence, whether it can be predicted and how it might be prevented, has become a major research topic in biomedicine. Here we show that efforts to predict disease emergence commonly conflate fundamentally different evolutionary and epidemiological time scales, and are likely to fail because of the enormous number of unsampled viruses that could conceivably emerge in humans. Although we know much about the patterns and processes of virus evolution on evolutionary t...

  9. Evolutionary principles and their practical application

    DEFF Research Database (Denmark)

    Hendry, A. P.; Kinnison, M. T.; Heino, M.

    2011-01-01

    are also increasingly incorporated into conservation biology, natural resource management, and environmental science. Examples include the protection of small and isolated populations from inbreeding depression, the identification of key traits involved in adaptation to climate change, the design......Evolutionary principles are now routinely incorporated into medicine and agriculture. Examples include the design of treatments that slow the evolution of resistance by weeds, pests, and pathogens, and the design of breeding programs that maximize crop yield or quality. Evolutionary principles...

  10. Evolutionary developmental genetics of fruit morphological variation within the Solanaceae

    Science.gov (United States)

    Wang, Li; Li, Jing; Zhao, Jing; He, Chaoying

    2015-01-01

    Morphological variations of fruits such as shape and size, and color are a result of adaptive evolution. The evolution of morphological novelties is particularly intriguing. An understanding of these evolutionary processes calls for the elucidation of the developmental and genetic mechanisms that result in particular fruit morphological characteristics, which determine seed dispersal. The genetic and developmental basis for fruit morphological variation was established at a microevolutionary time scale. Here, we summarize the progress on the evolutionary developmental genetics of fruit size, shape and color in the Solanaceae. Studies suggest that the recruitment of a pre-existing gene and subsequent modification of its interaction and regulatory networks are frequently involved in the evolution of morphological diversity. The basic mechanisms underlying changes in plant morphology are alterations in gene expression and/or gene function. We also deliberate on the future direction in evolutionary developmental genetics of fruit morphological variation such as fruit type. These studies will provide insights into plant developmental processes and will help to improve the productivity and fruit quality of crops. PMID:25918515

  11. Evolutionary game dynamics in populations with heterogenous structures.

    Directory of Open Access Journals (Sweden)

    Wes Maciejewski

    2014-04-01

    Full Text Available Evolutionary graph theory is a well established framework for modelling the evolution of social behaviours in structured populations. An emerging consensus in this field is that graphs that exhibit heterogeneity in the number of connections between individuals are more conducive to the spread of cooperative behaviours. In this article we show that such a conclusion largely depends on the individual-level interactions that take place. In particular, averaging payoffs garnered through game interactions rather than accumulating the payoffs can altogether remove the cooperative advantage of heterogeneous graphs while such a difference does not affect the outcome on homogeneous structures. In addition, the rate at which game interactions occur can alter the evolutionary outcome. Less interactions allow heterogeneous graphs to support more cooperation than homogeneous graphs, while higher rates of interactions make homogeneous and heterogeneous graphs virtually indistinguishable in their ability to support cooperation. Most importantly, we show that common measures of evolutionary advantage used in homogeneous populations, such as a comparison of the fixation probability of a rare mutant to that of the resident type, are no longer valid in heterogeneous populations. Heterogeneity causes a bias in where mutations occur in the population which affects the mutant's fixation probability. We derive the appropriate measures for heterogeneous populations that account for this bias.

  12. Deciphering the evolutionary history of open and closed mitosis.

    Science.gov (United States)

    Sazer, Shelley; Lynch, Michael; Needleman, Daniel

    2014-11-17

    The origin of the nucleus at the prokaryote-to-eukaryote transition represents one of the most important events in the evolution of cellular organization. The nuclear envelope encircles the chromosomes in interphase and is a selectively permeable barrier between the nucleoplasm and cytoplasm and an organizational scaffold for the nucleus. It remains intact in the 'closed' mitosis of some yeasts, but loses its integrity in the 'open' mitosis of mammals. Instances of both types of mitosis within two evolutionary clades indicate multiple evolutionary transitions between open and closed mitosis, although the underlying genetic changes that influenced these transitions remain unknown. A survey of the diversity of mitotic nuclei that fall between these extremes is the starting point from which to determine the physiologically relevant characteristics distinguishing open from closed mitosis and to understand how they evolved and why they are retained in present-day organisms. The field is now poised to begin addressing these issues by defining and documenting patterns of mitotic nuclear variation within and among species and mapping them onto a phylogenic tree. Deciphering the evolutionary history of open and closed mitosis will complement cell biological and genetic approaches aimed at deciphering the fundamental organizational principles of the nucleus. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. EvoOligo: oligonucleotide probe design with multiobjective evolutionary algorithms.

    Science.gov (United States)

    Shin, Soo-Yong; Lee, In-Hee; Cho, Young-Min; Yang, Kyung-Ae; Zhang, Byoung-Tak

    2009-12-01

    Probe design is one of the most important tasks in successful deoxyribonucleic acid microarray experiments. We propose a multiobjective evolutionary optimization method for oligonucleotide probe design based on the multiobjective nature of the probe design problem. The proposed multiobjective evolutionary approach has several distinguished features, compared with previous methods. First, the evolutionary approach can find better probe sets than existing simple filtering methods with fixed threshold values. Second, the multiobjective approach can easily incorporate the user's custom criteria or change the existing criteria. Third, our approach tries to optimize the combination of probes for the given set of genes, in contrast to other tools that independently search each gene for qualifying probes. Lastly, the multiobjective optimization method provides various sets of probe combinations, among which the user can choose, depending on the target application. The proposed method is implemented as a platform called EvoOligo and is available for service on the web. We test the performance of EvoOligo by designing probe sets for 19 types of Human Papillomavirus and 52 genes in the Arabidopsis Calmodulin multigene family. The design results from EvoOligo are proven to be superior to those from well-known existing probe design tools, such as OligoArray and OligoWiz.

  14. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...

  15. Strong interaction at finite temperature

    Indian Academy of Sciences (India)

    Abstract. We review two methods discussed in the literature to determine the effective parameters of strongly interacting particles as they move through a heat bath. The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules ...

  16. Strong-strong beam-beam simulation on parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Ji

    2004-08-02

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders.

  17. Strong-strong beam-beam simulation on parallel computer

    International Nuclear Information System (INIS)

    Qiang, Ji

    2004-01-01

    The beam-beam interaction puts a strong limit on the luminosity of the high energy storage ring colliders. At the interaction points, the electromagnetic fields generated by one beam focus or defocus the opposite beam. This can cause beam blowup and a reduction of luminosity. An accurate simulation of the beam-beam interaction is needed to help optimize the luminosity in high energy colliders

  18. Evolutionary computation in zoology and ecology.

    Science.gov (United States)

    Boone, Randall B

    2017-12-01

    Evolutionary computational methods have adopted attributes of natural selection and evolution to solve problems in computer science, engineering, and other fields. The method is growing in use in zoology and ecology. Evolutionary principles may be merged with an agent-based modeling perspective to have individual animals or other agents compete. Four main categories are discussed: genetic algorithms, evolutionary programming, genetic programming, and evolutionary strategies. In evolutionary computation, a population is represented in a way that allows for an objective function to be assessed that is relevant to the problem of interest. The poorest performing members are removed from the population, and remaining members reproduce and may be mutated. The fitness of the members is again assessed, and the cycle continues until a stopping condition is met. Case studies include optimizing: egg shape given different clutch sizes, mate selection, migration of wildebeest, birds, and elk, vulture foraging behavior, algal bloom prediction, and species richness given energy constraints. Other case studies simulate the evolution of species and a means to project shifts in species ranges in response to a changing climate that includes competition and phenotypic plasticity. This introduction concludes by citing other uses of evolutionary computation and a review of the flexibility of the methods. For example, representing species' niche spaces subject to selective pressure allows studies on cladistics, the taxon cycle, neutral versus niche paradigms, fundamental versus realized niches, community structure and order of colonization, invasiveness, and responses to a changing climate.

  19. Evolutionary cell biology: two origins, one objective.

    Science.gov (United States)

    Lynch, Michael; Field, Mark C; Goodson, Holly V; Malik, Harmit S; Pereira-Leal, José B; Roos, David S; Turkewitz, Aaron P; Sazer, Shelley

    2014-12-02

    All aspects of biological diversification ultimately trace to evolutionary modifications at the cellular level. This central role of cells frames the basic questions as to how cells work and how cells come to be the way they are. Although these two lines of inquiry lie respectively within the traditional provenance of cell biology and evolutionary biology, a comprehensive synthesis of evolutionary and cell-biological thinking is lacking. We define evolutionary cell biology as the fusion of these two eponymous fields with the theoretical and quantitative branches of biochemistry, biophysics, and population genetics. The key goals are to develop a mechanistic understanding of general evolutionary processes, while specifically infusing cell biology with an evolutionary perspective. The full development of this interdisciplinary field has the potential to solve numerous problems in diverse areas of biology, including the degree to which selection, effectively neutral processes, historical contingencies, and/or constraints at the chemical and biophysical levels dictate patterns of variation for intracellular features. These problems can now be examined at both the within- and among-species levels, with single-cell methodologies even allowing quantification of variation within genotypes. Some results from this emerging field have already had a substantial impact on cell biology, and future findings will significantly influence applications in agriculture, medicine, environmental science, and synthetic biology.

  20. Why an extended evolutionary synthesis is necessary.

    Science.gov (United States)

    Müller, Gerd B

    2017-10-06

    Since the last major theoretical integration in evolutionary biology-the modern synthesis (MS) of the 1940s-the biosciences have made significant advances. The rise of molecular biology and evolutionary developmental biology, the recognition of ecological development, niche construction and multiple inheritance systems, the '-omics' revolution and the science of systems biology, among other developments, have provided a wealth of new knowledge about the factors responsible for evolutionary change. Some of these results are in agreement with the standard theory and others reveal different properties of the evolutionary process. A renewed and extended theoretical synthesis, advocated by several authors in this issue, aims to unite pertinent concepts that emerge from the novel fields with elements of the standard theory. The resulting theoretical framework differs from the latter in its core logic and predictive capacities. Whereas the MS theory and its various amendments concentrate on genetic and adaptive variation in populations, the extended framework emphasizes the role of constructive processes, ecological interactions and systems dynamics in the evolution of organismal complexity as well as its social and cultural conditions. Single-level and unilinear causation is replaced by multilevel and reciprocal causation. Among other consequences, the extended framework overcomes many of the limitations of traditional gene-centric explanation and entails a revised understanding of the role of natural selection in the evolutionary process. All these features stimulate research into new areas of evolutionary biology.

  1. Evolutionary theories of aging and longevity.

    Science.gov (United States)

    Gavrilov, Leonid A; Gavrilova, Natalia S

    2002-02-07

    The purpose of this article is to provide students and researchers entering the field of aging studies with an introduction to the evolutionary theories of aging, as well as to orient them in the abundant modern scientific literature on evolutionary gerontology. The following three major evolutionary theories of aging are discussed: 1) the theory of programmed death suggested by August Weismann, 2) the mutation accumulation theory of aging suggested by Peter Medawar, and 3) the antagonistic pleiotropy theory of aging suggested by George Williams. We also discuss a special case of the antagonistic pleiotropy theory, the disposable soma theory developed by Tom Kirkwood and Robin Holliday. The theories are compared with each other as well as with recent experimental findings. At present the most viable evolutionary theories are the mutation accumulation theory and the antagonistic pleiotropy theory; these theories are not mutually exclusive, and they both may become a part of a future unifying theory of aging. Evolutionary theories of aging are useful because they open new opportunities for further research by suggesting testable predictions, but they have also been harmful in the past when they were used to impose limitations on aging studies. At this time, the evolutionary theories of aging are not ultimate completed theories, but rather a set of ideas that themselves require further elaboration and validation. This theoretical review article is written for a wide readership.

  2. Does the evolutionary conservation of microsatellite loci imply function?

    Energy Technology Data Exchange (ETDEWEB)

    Shriver, M.D.; Deka, R.; Ferrell, R.E. [Univ. of Pittsburgh, PA (United States)] [and others

    1994-09-01

    Microsatellites are highly polymorphic tandem arrays of short (1-6 bp) sequence motifs which have been found widely distributed in the genomes of all eukaryotes. We have analyzed allele frequency data on 16 microsatellite loci typed in the great apes (human, chimp, orangutan, and gorilla). The majority of these loci (13) were isolated from human genomic libraries; three were cloned from chimpanzee genomic DNA. Most of these loci are not only present in all apes species, but are polymorphic with comparable levels of heterozygosity and have alleles which overlap in size. The extent of divergence of allele frequencies among these four species were studies using the stepwise-weighted genetic distance (Dsw), which was previously shown to conform to linearity with evolutionary time since divergence for loci where mutations exist in a stepwise fashion. The phylogenetic tree of the great apes constructed from this distance matrix was consistent with the expected topology, with a high bootstrap confidence (82%) for the human/chimp clade. However, the allele frequency distributions of these species are 10 times more similar to each other than expected when they were calibrated with a conservative estimate of the time since separation of humans and the apes. These results are in agreement with sequence-based surveys of microsatellites which have demonstrated that they are highly (90%) conserved over short periods of evolutionary time (< 10 million years) and moderately (30%) conserved over long periods of evolutionary time (> 60-80 million years). This evolutionary conservation has prompted some authors to speculate that there are functional constraints on microsatellite loci. In contrast, the presence of directional bias of mutations with constraints and/or selection against aberrant sized alleles can explain these results.

  3. The evolutionary origins and ecological context of tool use in New Caledonian crows.

    Science.gov (United States)

    Rutz, Christian; St Clair, James J H

    2012-02-01

    New Caledonian (NC) crows Corvus moneduloides are the most prolific avian tool users. In the wild, they use at least three distinct tool types to extract invertebrate prey from deadwood and vegetation, with some of their tools requiring complex manufacture, modification and/or deployment. Experiments with captive-bred, hand-raised NC crows have demonstrated that the species has a strong genetic predisposition for basic tool use and manufacture, suggesting that this behaviour is an evolved adaptation. This view is supported by recent stable-isotope analyses of the diets of wild crows, which revealed that tool use provides access to highly profitable hidden prey, with preliminary data indicating that parents preferentially feed their offspring with tool-derived food. Building on this work, our review examines the possible evolutionary origins of these birds' remarkable tool-use behaviour. Whilst robust comparative analyses are impossible, given the phylogenetic rarity of animal tool use, our examination of a wide range of circumstantial evidence enables a first attempt at reconstructing a plausible evolutionary scenario. We suggest that a common ancestor of NC crows, originating from a (probably) non-tool-using South-East Asian or Australasian crow population, colonised New Caledonia after its last emersion several million years ago. The presence of profitable but out-of-reach food, in combination with a lack of direct competition for these resources, resulted in a vacant woodpecker-like niche. Crows may have possessed certain behavioural and/or morphological features upon their arrival that predisposed them to express tool-use rather than specialised prey-excavation behaviour, although it is possible that woodpecker-like foraging preceded tool use. Low levels of predation risk may have further facilitated tool-use behaviour, by allowing greater expenditure of time and energy on object interaction and exploration, as well as the evolution of a 'slow' life-history, in

  4. The mitochondrial genome of the ascalaphid owlfly Libelloides macaronius and comparative evolutionary mitochondriomics of neuropterid insects

    Science.gov (United States)

    2011-01-01

    Background The insect order Neuroptera encompasses more than 5,700 described species. To date, only three neuropteran mitochondrial genomes have been fully and one partly sequenced. Current knowledge on neuropteran mitochondrial genomes is limited, and new data are strongly required. In the present work, the mitochondrial genome of the ascalaphid owlfly Libelloides macaronius is described and compared with the known neuropterid mitochondrial genomes: Megaloptera, Neuroptera and Raphidioptera. These analyses are further extended to other endopterygotan orders. Results The mitochondrial genome of L. macaronius is a circular molecule 15,890 bp long. It includes the entire set of 37 genes usually present in animal mitochondrial genomes. The gene order of this newly sequenced genome is unique among Neuroptera and differs from the ancestral type of insects in the translocation of trnC. The L. macaronius genome shows the lowest A+T content (74.50%) among known neuropterid genomes. Protein-coding genes possess the typical mitochondrial start codons, except for cox1, which has an unusual ACG. Comparisons among endopterygotan mitochondrial genomes showed that A+T content and AT/GC-skews exhibit a broad range of variation among 84 analyzed taxa. Comparative analyses showed that neuropterid mitochondrial protein-coding genes experienced complex evolutionary histories, involving features ranging from codon usage to rate of substitution, that make them potential markers for population genetics/phylogenetics studies at different taxonomic ranks. The 22 tRNAs show variable substitution patterns in Neuropterida, with higher sequence conservation in genes located on the α strand. Inferred secondary structures for neuropterid rrnS and rrnL genes largely agree with those known for other insects. For the first time, a model is provided for domain I of an insect rrnL. The control region in Neuropterida, as in other insects, is fast-evolving genomic region, characterized by AT

  5. Exploring social influence on evolutionary prisoner’s dilemma games in networks

    Science.gov (United States)

    Zong, Hengshan; Jia, Guozhu; Cheng, Yang

    2015-11-01

    Though numerous studies demonstrate the importance of social influence in deciding individual decision-making process in networks, little has been done to explore its impact on players’ behavioral patterns in evolutionary prisoner’s dilemma games (PDGs). This study investigates how social influenced strategy updating rules may affect the final equilibrium of game dynamics. The results show that weak social influence usually inhibits cooperation, while strong social influence has a mediating effect. The impacts of network structure and the existence of rebels in social influence scenarios are also tested. The paper provides a comprehensive interpretation on social influence effects on evolutionary PDGs in networks.

  6. A survey of evolutionary policy: normative and positive dimensions

    NARCIS (Netherlands)

    van den Bergh, J.C.J.M.; Kallis, G.

    2013-01-01

    We explore public policy from the perspective of evolutionary analysis. Potential entry points for developing a normative evolutionary policy theory are examined, which involves a critical examination of the related idea of "evolutionary progress". The meaning of evolutionary policy is next studied

  7. Evolutionary Biology Instruction: What Students Gain from Learning through Inquiry.

    Science.gov (United States)

    Dremock, Fae, Ed.

    2002-01-01

    This bulletin features articles on real world evolutionary biology, revolutionary classroom science, a review of new curricula in evolutionary biology, and the use of case studies to illustrate points in evolutionary biology. The articles are: (1) "'Real World' Evolutionary Biology: A Pragmatic Quest. Interview with BioQUEST's John Jungck" (Harvey…

  8. Cosmological applications of strong gravitational lensing

    DEFF Research Database (Denmark)

    Paraficz, Danuta

    value of the energy density of the two above components, together with measuring the Hubble constant that determines the age of the Universe, is a major goal of modern astrophysics. An interesting method for estimating these parameters is strong gravitational lensing of quasars (QSOs). As shown...... by Refsdal (1964), H0, !m and !! can be measured based on the time delay ("t) between multiply lensed images of QSOs, because "t depends on H0 and on the distances to lens and source, hence!m and !!. Determination of cosmological parameters using gravitational lensing suffers from some degeneracies......, but it is based on well understood physics and unlike distance ladder methods there are no calibration issues. Moreover, it has an advantage over some of the leading methods (such as Type Ia SNe) in that it is a purely cosmological approach. In this thesis, the property of strong gravitational lensing - time...

  9. Strongly correlated systems experimental techniques

    CERN Document Server

    Mancini, Ferdinando

    2015-01-01

    The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...

  10. Strongly Correlated Systems Theoretical Methods

    CERN Document Server

    Avella, Adolfo

    2012-01-01

    The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...

  11. Strongly correlated systems numerical methods

    CERN Document Server

    Mancini, Ferdinando

    2013-01-01

    This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...

  12. Strongly nonlinear oscillators analytical solutions

    CERN Document Server

    Cveticanin, Livija

    2014-01-01

    This book provides the presentation of the motion of pure nonlinear oscillatory systems and various solution procedures which give the approximate solutions of the strong nonlinear oscillator equations. The book presents the original author’s method for the analytical solution procedure of the pure nonlinear oscillator system. After an introduction, the physical explanation of the pure nonlinearity and of the pure nonlinear oscillator is given. The analytical solution for free and forced vibrations of the one-degree-of-freedom strong nonlinear system with constant and time variable parameter is considered. Special attention is given to the one and two mass oscillatory systems with two-degrees-of-freedom. The criteria for the deterministic chaos in ideal and non-ideal pure nonlinear oscillators are derived analytically. The method for suppressing chaos is developed. Important problems are discussed in didactic exercises. The book is self-consistent and suitable as a textbook for students and also for profess...

  13. Flavour Democracy in Strong Unification

    CERN Document Server

    Abel, S A; Abel, Steven; King, Steven

    1998-01-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of "strong unification". Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged $SU(3)_L\\times SU(3)_R$ family symmetry which illustrates our approach.

  14. Evolutionary explanations in medical and health profession courses: are you answering your students' "why" questions?

    Directory of Open Access Journals (Sweden)

    Malyango Avelin A

    2005-05-01

    Full Text Available Abstract Background Medical and pre-professional health students ask questions about human health that can be answered in two ways, by giving proximate and evolutionary explanations. Proximate explanations, most common in textbooks and classes, describe the immediate scientifically known biological mechanisms of anatomical characteristics or physiological processes. These explanations are necessary but insufficient. They can be complemented with evolutionary explanations that describe the evolutionary processes and principles that have resulted in human biology we study today. The main goal of the science of Darwinian Medicine is to investigate human disease, disorders, and medical complications from an evolutionary perspective. Discussion This paper contrasts the differences between these two types of explanations by describing principles of natural selection that underlie medical questions. Thus, why is human birth complicated? Why does sickle cell anemia exist? Why do we show symptoms like fever, diarrhea, and coughing when we have infection? Why do we suffer from ubiquitous age-related diseases like arteriosclerosis, Alzheimer's and others? Why are chronic diseases like type II diabetes and obesity so prevalent in modern society? Why hasn't natural selection eliminated the genes that cause common genetic diseases like hemochromatosis, cystic fibrosis, Tay sachs, PKU and others? Summary In giving students evolutionary explanations professors should underscore principles of natural selection, since these can be generalized for the analysis of many medical questions. From a research perspective, natural selection seems central to leading hypotheses of obesity and type II diabetes and might very well explain the occurrence of certain common genetic diseases like cystic fibrosis, hemochromatosis, Tay sachs, Fragile X syndrome, G6PD and others because of their compensating advantages. Furthermore, armed with evolutionary explanations, health care

  15. Uxoricide in pregnancy: ancient Greek domestic violence in evolutionary perspective.

    Science.gov (United States)

    Deacy, Susan; McHardy, Fiona

    2013-10-24

    Previous studies of ancient Greek examples of uxoricide in pregnancy have concluded that the theme is used to suggest tyrannical abuse of power and that the violence is a product of the patriarchal nature of ancient society. This article uses evolutionary analyses of violence during pregnancy to argue that the themes of sexual jealousy and uncertainty over paternity are as crucial as the theme of power to an understanding of these examples and that the examples can be seen as typical instances of spousal abuse as it occurs in all types of society.

  16. An Evolutionary Approach for Robust Layout Synthesis of MEMS

    DEFF Research Database (Denmark)

    Fan, Zhun; Wang, Jiachuan; Goodman, Erik

    2005-01-01

    The paper introduces a robust design method for layout synthesis of MEM resonators subject to inherent geometric uncertainties such as the fabrication error on the sidewall of the structure. The robust design problem is formulated as a multi-objective constrained optimisation problem after certain...... assumptions and treated with multiobjective genetic algorithm (MOGA), a special type of evolutionary computing approaches. Case study based on layout synthesis of a comb-driven MEM resonator shows that the approach proposed in this paper can lead to design results that meet the target performance and are less...

  17. Global existence and uniqueness of nonlinear evolutionary fluid equations

    CERN Document Server

    Qin, Yuming; Wang, Taige

    2015-01-01

    This book presents recent results on nonlinear evolutionary fluid equations such as the compressible (radiative) magnetohydrodynamics (MHD) equations, compressible viscous micropolar fluid equations, the full non-Newtonian fluid equations and non-autonomous compressible Navier-Stokes equations. These types of partial differential equations arise in many fields of mathematics, but also in other branches of science such as physics and fluid dynamics. This book will be a valuable resource for graduate students and researchers interested in partial differential equations, and will also benefit practitioners in physics and engineering.

  18. Transmissible cancers in an evolutionary context.

    Science.gov (United States)

    Ujvari, Beata; Papenfuss, Anthony T; Belov, Katherine

    2016-07-01

    Cancer is an evolutionary and ecological process in which complex interactions between tumour cells and their environment share many similarities with organismal evolution. Tumour cells with highest adaptive potential have a selective advantage over less fit cells. Naturally occurring transmissible cancers provide an ideal model system for investigating the evolutionary arms race between cancer cells and their surrounding micro-environment and macro-environment. However, the evolutionary landscapes in which contagious cancers reside have not been subjected to comprehensive investigation. Here, we provide a multifocal analysis of transmissible tumour progression and discuss the selection forces that shape it. We demonstrate that transmissible cancers adapt to both their micro-environment and macro-environment, and evolutionary theories applied to organisms are also relevant to these unique diseases. The three naturally occurring transmissible cancers, canine transmissible venereal tumour (CTVT) and Tasmanian devil facial tumour disease (DFTD) and the recently discovered clam leukaemia, exhibit different evolutionary phases: (i) CTVT, the oldest naturally occurring cell line is remarkably stable; (ii) DFTD exhibits the signs of stepwise cancer evolution; and (iii) clam leukaemia shows genetic instability. While all three contagious cancers carry the signature of ongoing and fairly recent adaptations to selective forces, CTVT appears to have reached an evolutionary stalemate with its host, while DFTD and the clam leukaemia appear to be still at a more dynamic phase of their evolution. Parallel investigation of contagious cancer genomes and transcriptomes and of their micro-environment and macro-environment could shed light on the selective forces shaping tumour development at different time points: during the progressive phase and at the endpoint. A greater understanding of transmissible cancers from an evolutionary ecology perspective will provide novel avenues for

  19. Dynamic Heat Transfer Model of Refrigerated Foodstuff<strong> strong>

    DEFF Research Database (Denmark)

    Cai, Junping; Risum, Jørgen; Thybo, Claus

    2006-01-01

    condition. The influence of different factors such as air velocity, type of food, size of food, or food package are investigated, the question such as what kind of food are more sensitive to the surrounding temperature change is answered. This model can serve as a prerequisite for modelling of food quality...

  20. Evolutionary theories of aging. 1. The need to understand the process of natural selection.

    Science.gov (United States)

    Keller, L; Genoud, M

    1999-01-01

    In a Forum article Le Bourg (1998) criticized recent tests of evolutionary theories of aging and suggested alternative explanations for the long lifespan of ant queens and the positive relationship between body size and lifespan in mammals. Moreover, he attempts to criticize evolutionary theories of aging by showing that explanations other than evolutionary theories of aging probably account for the variation in human lifespan across countries. Here we show that the arguments of Le Bourg suffer several problems. First, many of the arguments reveal a misunderstanding of the process of natural selection. Second, some of the arguments reflect a lack of knowledge of evolutionary theories of aging (e.g. pre-reproductive mortality is not predicted to influence lifespan of organisms contrary to what is claimed). Finally, his final example on lifespan in humans simply is a straw-man because serious evolutionary biologists are well aware of the importance of confounding variables and would certainly not make the type of conclusion suggested by Le Bourg. Although a critical discussion of evolutionary theories of aging is welcome, we believe that the alternative explanations proposed by Le Bourg are implausible and reflect a misunderstanding of the process of natural selection. Copyright 1999 S. Karger AG, Basel

  1. The Dark Side of Strongly Coupled Theories

    DEFF Research Database (Denmark)

    Kouvaris, Christoforos

    2008-01-01

    We investigate the constraints of dark matter search experiments on the different candidates emerging from the minimal quasi-conformal strong coupling theory with fermions in the adjoint representation. For one candidate, the current limits of CDMS exclude a tiny window of masses around 120 GeV. We...... also investigate under what circumstances the newly proposed candidate composed of a -2 negatively charged particle and a $^4He^{+2}$ can explain the discrepancy between the results of the CDMS and DAMA experiments. We found that this type of dark matter should give negative results in CDMS, while...

  2. First Detection of a Strong Magnetic Field on a Bursty Brown Dwarf: Puzzle Solved

    Science.gov (United States)

    Berdyugina, S. V.; Harrington, D. M.; Kuzmychov, O.; Kuhn, J. R.; Hallinan, G.; Kowalski, A. F.; Hawley, S. L.

    2017-09-01

    We report the first direct detection of a strong, 5 kG magnetic field on the surface of an active brown dwarf. LSR J1835+3259 is an M8.5 dwarf exhibiting transient radio and optical emission bursts modulated by fast rotation. We have detected the surface magnetic field as circularly polarized signatures in the 819 nm sodium lines when an active emission region faced the Earth. Modeling Stokes profiles of these lines reveals the effective temperature of 2800 K and log gravity acceleration of 4.5. These parameters place LSR J1835+3259 on evolutionary tracks as a young brown dwarf with the mass of 55+/- 4{M}{{J}} and age of 22 ± 4 Myr. Its magnetic field is at least 5.1 kG and covers at least 11% of the visible hemisphere. The active region topology recovered using line profile inversions comprises hot plasma loops with a vertical stratification of optical and radio emission sources. These loops rotate with the dwarf in and out of view causing periodic emission bursts. The magnetic field is detected at the base of the loops. This is the first time that we can quantitatively associate brown dwarf non-thermal bursts with a strong, 5 kG surface magnetic field and solve the puzzle of their driving mechanism. This is also the coolest known dwarf with such a strong surface magnetic field. The young age of LSR J1835+3259 implies that it may still maintain a disk, which may facilitate bursts via magnetospheric accretion, like in higher-mass T Tau-type stars. Our results pave a path toward magnetic studies of brown dwarfs and hot Jupiters.

  3. Population and evolutionary dynamics in spatially structured seasonally varying environments.

    Science.gov (United States)

    Reid, Jane M; Travis, Justin M J; Daunt, Francis; Burthe, Sarah J; Wanless, Sarah; Dytham, Calvin

    2018-03-25

    Increasingly imperative objectives in ecology are to understand and forecast population dynamic and evolutionary responses to seasonal environmental variation and change. Such population and evolutionary dynamics result from immediate and lagged responses of all key life-history traits, and resulting demographic rates that affect population growth rate, to seasonal environmental conditions and population density. However, existing population dynamic and eco-evolutionary theory and models have not yet fully encompassed within-individual and among-individual variation, covariation, structure and heterogeneity, and ongoing evolution, in a critical life-history trait that allows individuals to respond to seasonal environmental conditions: seasonal migration. Meanwhile, empirical studies aided by new animal-tracking technologies are increasingly demonstrating substantial within-population variation in the occurrence and form of migration versus year-round residence, generating diverse forms of 'partial migration' spanning diverse species, habitats and spatial scales. Such partially migratory systems form a continuum between the extreme scenarios of full migration and full year-round residence, and are commonplace in nature. Here, we first review basic scenarios of partial migration and associated models designed to identify conditions that facilitate the maintenance of migratory polymorphism. We highlight that such models have been fundamental to the development of partial migration theory, but are spatially and demographically simplistic compared to the rich bodies of population dynamic theory and models that consider spatially structured populations with dispersal but no migration, or consider populations experiencing strong seasonality and full obligate migration. Second, to provide an overarching conceptual framework for spatio-temporal population dynamics, we define a 'partially migratory meta-population' system as a spatially structured set of locations that can

  4. Evolutionary accounts of human behavioural diversity

    Science.gov (United States)

    Brown, Gillian R.; Dickins, Thomas E.; Sear, Rebecca; Laland, Kevin N.

    2011-01-01

    Human beings persist in an extraordinary range of ecological settings, in the process exhibiting enormous behavioural diversity, both within and between populations. People vary in their social, mating and parental behaviour and have diverse and elaborate beliefs, traditions, norms and institutions. The aim of this theme issue is to ask whether, and how, evolutionary theory can help us to understand this diversity. In this introductory article, we provide a background to the debate surrounding how best to understand behavioural diversity using evolutionary models of human behaviour. In particular, we examine how diversity has been viewed by the main subdisciplines within the human evolutionary behavioural sciences, focusing in particular on the human behavioural ecology, evolutionary psychology and cultural evolution approaches. In addition to differences in focus and methodology, these subdisciplines have traditionally varied in the emphasis placed on human universals, ecological factors and socially learned behaviour, and on how they have addressed the issue of genetic variation. We reaffirm that evolutionary theory provides an essential framework for understanding behavioural diversity within and between human populations, but argue that greater integration between the subfields is critical to developing a satisfactory understanding of diversity. PMID:21199836

  5. Initialization strategies and diversity in evolutionary timetabling.

    Science.gov (United States)

    Burke, E K; Newall, J P; Weare, R F

    1998-01-01

    This document seeks to provide a scientific basis by which different initialization algorithms for evolutionary timetabling may be compared. Seeding the initial population may be used to improve initial quality and provide a better starting point for the evolutionary algorithm. This must be tempered against the consideration that if the seeding algorithm produces very similar solutions, then the loss of genetic diversity may well lead to a worse final solution. Diversity, we hope, provides a good indication of how good the final solution will be, although only by running the evolutionary algorithm will the exact result be found. We will investigate the effects of heuristic seeding by taking quality and diversity measures of populations generated by heuristic initialization methods on both random and real-life data, as well as assessing the long-term performance of an evolutionary algorithm (found to work well on the timetabling problem) when using heuristic initialization. This will show how the use of heuristic initialization strategies can substantially improve the performance of evolutionary algorithms for the timetabling problem.

  6. Atoms in strong laser fields

    International Nuclear Information System (INIS)

    L'Huillier, A.

    2002-01-01

    When a high-power laser focuses into a gas of atoms, the electromagnetic field becomes of the same magnitude as the Coulomb field which binds a 1s electron in a hydrogen atom. 3 highly non-linear phenomena can happen: 1) ATI (above threshold ionization): electrons initially in the ground state absorb a large number of photons, many more than the minimum number required for ionization; 2) multiple ionization: many electrons can be emitted one at a time, in a sequential process, or simultaneously in a mechanism called direct or non-sequential; and 3) high order harmonic generation (HHG): efficient photon emission in the extreme ultraviolet range, in the form of high-order harmonics of the fundamental laser field can occur. The theoretical problem consists in solving the time dependent Schroedinger equation (TDSE) that describes the interaction of a many-electron atom with a laser field. A number of methods have been proposed to solve this problem in the case of a hydrogen atom or a single-active electron atom in a strong laser field. A large effort is presently being devoted to go beyond the single-active approximation. The understanding of the physics of the interaction between atoms and strong laser fields has been provided by a very simple model called ''simple man's theory''. A unified view of HHG, ATI, and non-sequential ionization, originating from the simple man's model and the strong field approximation, expressed in terms of electrons trajectories or quantum paths is slowly emerging. (A.C.)

  7. Strongly Interacting Light Dark Matter

    Directory of Open Access Journals (Sweden)

    Sebastian Bruggisser, Francesco Riva, Alfredo Urbano

    2017-09-01

    Full Text Available In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM can appear weakly coupled at small energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo Nambu-Goldstone Bosons and Goldstini are interesting targets for LHC missing-energy searches.

  8. Strongly interacting light dark matter

    International Nuclear Information System (INIS)

    Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo

    2016-07-01

    In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.

  9. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  10. Scalar strong interaction hadron theory

    CERN Document Server

    Hoh, Fang Chao

    2015-01-01

    The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.

  11. Strong Plate, Weak Slab Dichotomy

    Science.gov (United States)

    Petersen, R. I.; Stegman, D. R.; Tackley, P.

    2015-12-01

    Models of mantle convection on Earth produce styles of convection that are not observed on Earth.Moreover non-Earth-like modes, such as two-sided downwellings, are the de facto mode of convection in such models.To recreate Earth style subduction, i.e. one-sided asymmetric recycling of the lithosphere, proper treatment of the plates and plate interface are required. Previous work has identified several model features that promote subduction. A free surface or pseudo-free surface and a layer of material with a relatively low strength material (weak crust) allow downgoing plates to bend and slide past overriding without creating undue stress at the plate interface. (Crameri, et al. 2012, GRL)A low viscosity mantle wedge, possibly a result of slab dehydration, decouples the plates in the system. (Gerya et al. 2007, Geo)Plates must be composed of material which, in the case of the overriding plate, are is strong enough to resist bending stresses imposed by the subducting plate and yet, as in the case of the subducting plate, be weak enough to bend and subduct when pulled by the already subducted slab. (Petersen et al. 2015, PEPI) Though strong surface plates are required for subduction such plates may present a problem when they encounter the lower mantle.As the subducting slab approaches the higher viscosity, lower mantle stresses are imposed on the tip.Strong slabs transmit this stress to the surface.There the stress field at the plate interface is modified and potentially modifies the style of convection. In addition to modifying the stress at the plate interface, the strength of the slab affects the morphology of the slab at the base of the upper mantle. (Stegman, et al 2010, Tectonophysics)Slabs that maintain a sufficient portion of their strength after being bent require high stresses to unbend or otherwise change their shape.On the other hand slabs that are weakened though the bending process are more amenable to changes in morphology. We present the results of

  12. Evolutionary history of lagomorphs in response to global environmental change.

    Directory of Open Access Journals (Sweden)

    Deyan Ge

    Full Text Available Although species within Lagomorpha are derived from a common ancestor, the distribution range and body size of its two extant groups, ochotonids and leporids, are quite differentiated. It is unclear what has driven their disparate evolutionary history. In this study, we compile and update all fossil records of Lagomorpha for the first time, to trace the evolutionary processes and infer their evolutionary history using mitochondrial genes, body length and distribution of extant species. We also compare the forage selection of extant species, which offers an insight into their future prospects. The earliest lagomorphs originated in Asia and later diversified in different continents. Within ochotonids, more than 20 genera occupied the period from the early Miocene to middle Miocene, whereas most of them became extinct during the transition from the Miocene to Pliocene. The peak diversity of the leporids occurred during the Miocene to Pliocene transition, while their diversity dramatically decreased in the late Quaternary. Mantel tests identified a positive correlation between body length and phylogenetic distance of lagomorphs. The body length of extant ochotonids shows a normal distribution, while the body length of extant leporids displays a non-normal pattern. We also find that the forage selection of extant pikas features a strong preference for C(3 plants, while for the diet of leporids, more than 16% of plant species are identified as C(4 (31% species are from Poaceae. The ability of several leporid species to consume C(4 plants is likely to result in their size increase and range expansion, most notably in Lepus. Expansion of C(4 plants in the late Miocene, the so-called 'nature's green revolution', induced by global environmental change, is suggested to be one of the major 'ecological opportunities', which probably drove large-scale extinction and range contraction of ochotonids, but inversely promoted diversification and range expansion of

  13. Multiple coding and the evolutionary properties of RNA secondary structure.

    Science.gov (United States)

    Huynen, M A; Konings, D A; Hogeweg, P

    1993-11-21

    This article evaluates evolutionary properties of the transition from RNA primary sequence to RNA secondary structure. It focuses on the restrictions that the conservation of a protein code in an RNA sequence puts on its potential to evolve towards a specific secondary structure. Restricting the mutations to those that do not affect the coding for a protein restricts both the accessibility and the connectivity of the sequence space. The accessibility is restricted because only certain point mutations are allowed. The connectivity is restricted because no insertions and deletions are allowed. Simulating an evolutionary search process for a specific secondary structure shows that (i) the reduction of allowable point mutations allows for adaptation to some large-scale topology, but strongly reduces the possibility of small-scale adaptations, (ii) the abolition of insertions and deletions has very little effect on the results of the search process. During the evolutionary search process for a secondary structure with a specific topology and a high frequency of base-pairing the quasispecies moves into a subspace in which the similarity between secondary structures of neighboring sequences is relatively high. Increased similarity between second structures of neighboring sequences is also found in the Rev responsive element (RRE) in the lentiviruses Caprine arthritis-encephalitis virus and Visna virus. In these viruses a biased nucleotide frequency in the RRE region suggests that selection for the RRE RNA secondary structure affects the amino acid sequence of the env gene. Our results show a variation in the ruggedness of fitness landscapes which are based on a high degree of epistatic interactions. Fitness landscapes play an essential role, not only in biotic evolution, but also in all kinds of optimization processes (Hill Climbing, Simulated Annealing, Genetic Algorithms, etc). Variation in their ruggedness should therefore be taken into account in the analysis of these

  14. Evolutionary radiation of earless frogs in the Andes: molecular phylogenetics and habitat shifts in high-elevation terrestrial breeding frogs

    Directory of Open Access Journals (Sweden)

    Rudolf von May

    2018-02-01

    Full Text Available The loss of hearing structures and loss of advertisement calls in many terrestrial breeding frogs (Strabomantidae living at high elevations in South America are common and intriguing phenomena. The Andean frog genus Phrynopus Peters, 1873 has undergone an evolutionary radiation in which most species lack the tympanic membrane and tympanic annulus, yet the phylogenetic relationships among species in this group remain largely unknown. Here, we present an expanded molecular phylogeny of Phrynopus that includes 24 nominal species. Our phylogeny includes Phrynopus peruanus, the type species of the genus, and 10 other species for which genetic data were previously unavailable. We found strong support for monophyly of Phrynopus, and that two nominal species—Phrynopus curator and Phrynopus nicoleae—are junior synonyms of Phrynopus tribulosus. Using X-ray computed tomography (CT imaging, we demonstrate that the absence of external hearing structures is associated with complete loss of the auditory skeletal elements (columella in at least one member of the genus. We mapped the tympanum condition on to a species tree to infer whether the loss of hearing structures took place once or multiple times. We also assessed whether tympanum condition, body size, and body shape are associated with the elevational distribution and habitat use. We identified a single evolutionary transition that involved the loss of both the tympanic membrane and tympanic annulus, which in turn is correlated with the absence of advertisement calls. We also identified several species pairs where one species inhabits the Andean grassland and the other montane forest. When accounting for phylogenetic relatedness among species, we detected a significant pattern of increasing body size with increasing elevation. Additionally, species at higher elevations tend to develop shorter limbs, shorter head, and shorter snout than species living at lower elevations. Our findings strongly suggest

  15. The Race for Evolutionary Success

    Directory of Open Access Journals (Sweden)

    Dorian Stiefel

    2012-08-01

    Full Text Available The Earth appears to be at the beginning of sixth massive species extinction. This paper balances a review of the forces threatening species survival with a comprehensive scan of factors that could act as counterweights. These factors could lead to four types of evolution—cultural, regulatory, ecological, and technological—that could individually or in combination avert massive species extinction if humans implement solutions faster than new problems arise. Implications and future research opportunities are also explored.

  16. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    Science.gov (United States)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed

  17. Evolutionary Sound Synthesis Controlled by Gestural Data

    Directory of Open Access Journals (Sweden)

    Jose Fornari

    2011-05-01

    Full Text Available This article focuses on the interdisciplinary research involving Computer Music and Generative Visual Art. We describe the implementation of two interactive artistic systems based on principles of Gestural Data (WILSON, 2002 retrieval and self-organization (MORONI, 2003, to control an Evolutionary Sound Synthesis method (ESSynth. The first implementation uses, as gestural data, image mapping of handmade drawings. The second one uses gestural data from dynamic body movements of dance. The resulting computer output is generated by an interactive system implemented in Pure Data (PD. This system uses principles of Evolutionary Computation (EC, which yields the generation of a synthetic adaptive population of sound objects. Considering that music could be seen as “organized sound” the contribution of our study is to develop a system that aims to generate "self-organized sound" – a method that uses evolutionary computation to bridge between gesture, sound and music.

  18. The evolutionary implications of epigenetic inheritance.

    Science.gov (United States)

    Jablonka, Eva

    2017-10-06

    The Modern Evolutionary Synthesis (MS) forged in the mid-twentieth century was built on a notion of heredity that excluded soft inheritance, the inheritance of the effects of developmental modifications. However, the discovery of molecular mechanisms that generate random and developmentally induced epigenetic variations is leading to a broadening of the notion of biological heredity that has consequences for ideas about evolution. After presenting some old challenges to the MS that were raised, among others, by Karl Popper, I discuss recent research on epigenetic inheritance, which provides experimental and theoretical support for these challenges. There is now good evidence that epigenetic inheritance is ubiquitous and is involved in adaptive evolution and macroevolution. I argue that the many evolutionary consequences of epigenetic inheritance open up new research areas and require the extension of the evolutionary synthesis beyond the current neo-Darwinian model.

  19. Evolutionary stability concepts in a stochastic environment

    Science.gov (United States)

    Zheng, Xiu-Deng; Li, Cong; Lessard, Sabin; Tao, Yi

    2017-09-01

    Over the past 30 years, evolutionary game theory and the concept of an evolutionarily stable strategy have been not only extensively developed and successfully applied to explain the evolution of animal behaviors, but also widely used in economics and social sciences. Nonetheless, the stochastic dynamical properties of evolutionary games in randomly fluctuating environments are still unclear. In this study, we investigate conditions for stochastic local stability of fixation states and constant interior equilibria in a two-phenotype model with random payoffs following pairwise interactions. Based on this model, we develop the concepts of stochastic evolutionary stability (SES) and stochastic convergence stability (SCS). We show that the condition for a pure strategy to be SES and SCS is more stringent than in a constant environment, while the condition for a constant mixed strategy to be SES is less stringent than the condition to be SCS, which is less stringent than the condition in a constant environment.

  20. Democratizing evolutionary biology, lessons from insects.

    Science.gov (United States)

    Dunn, Robert R; Beasley, DeAnna E

    2016-12-01

    The engagement of the public in the scientific process is an old practice. Yet with recent advances in technology, the role of the citizen scientist in studying evolutionary processes has increased. Insects provide ideal models for understanding these evolutionary processes at large scales. This review highlights how insect-based citizen science has led to the expansion of specimen collections and reframed research questions in light of new observations and unexpected discoveries. Given the rapid expansion of human-modified (and inhabited) environments, the degree to which the public can participate in insect-based citizen science will allow us to track and monitor evolutionary trends at a global scale. Copyright © 2016. Published by Elsevier Inc.

  1. Studying AMPK in an Evolutionary Context.

    Science.gov (United States)

    Jain, Arpit; Roustan, Valentin; Weckwerth, Wolfram; Ebersberger, Ingo

    2018-01-01

    The AMPK protein kinase forms the heart of a complex network controlling the metabolic activities in a eukaryotic cell. Unraveling the steps by which this pathway evolved from its primordial roots in the last eukaryotic common ancestor to its present status in contemporary species has the potential to shed light on the evolution of eukaryotes. A homolog search for the proteins interacting in this pathway is considerably straightforward. However, interpreting the results, when reconstructing the evolutionary history of the pathway over larger evolutionary distances, bears a number of pitfalls. With this in mind, we present a protocol to trace a metabolic pathway across contemporary species and backward in evolutionary time. Alongside the individual analysis steps, we provide guidelines for data interpretation generalizing beyond the analysis of AMPK.

  2. Infrastructure system restoration planning using evolutionary algorithms

    Science.gov (United States)

    Corns, Steven; Long, Suzanna K.; Shoberg, Thomas G.

    2016-01-01

    This paper presents an evolutionary algorithm to address restoration issues for supply chain interdependent critical infrastructure. Rapid restoration of infrastructure after a large-scale disaster is necessary to sustaining a nation's economy and security, but such long-term restoration has not been investigated as thoroughly as initial rescue and recovery efforts. A model of the Greater Saint Louis Missouri area was created and a disaster scenario simulated. An evolutionary algorithm is used to determine the order in which the bridges should be repaired based on indirect costs. Solutions were evaluated based on the reduction of indirect costs and the restoration of transportation capacity. When compared to a greedy algorithm, the evolutionary algorithm solution reduced indirect costs by approximately 12.4% by restoring automotive travel routes for workers and re-establishing the flow of commodities across the three rivers in the Saint Louis area.

  3. Evolutionary responses of native plant species to invasive plants: a review.

    Science.gov (United States)

    Oduor, Ayub M O

    2013-12-01

    Strong competition from invasive plant species often leads to declines in abundances and may, in certain cases, cause localized extinctions of native plant species. Nevertheless, studies have shown that certain populations of native plant species can co-exist with invasive plant species,suggesting the possibility of adaptive evolutionary responses of those populations to the invasive plants. Empirical inference of evolutionary responses of the native plant species to invasive plants has involved experiments comparing two conspecific groups of native plants for differences in expression of growth/reproductive traits: populations that have experienced competition from the invasive plant species (i.e. experienced natives) versus populations with no known history of interactions with the invasive plant species (i.e. naıve natives). Here, I employ a meta-analysis to obtain a general pattern of inferred evolutionary responses of native plant species from 53 such studies. In general, the experienced natives had significantly higher growth/reproductive performances than naıve natives, when grown with or without competition from invasive plants.While the current results indicate that certain populations of native plant species could potentially adapt evolutionarily to invasive plant species, the ecological and evolutionary mechanisms that probably underlie such evolutionary responses remain unexplored and should be the focus of future studies.

  4. On Reciprocal Causation in the Evolutionary Process.

    Science.gov (United States)

    Svensson, Erik I

    2018-01-01

    Recent calls for a revision of standard evolutionary theory (SET) are based partly on arguments about the reciprocal causation. Reciprocal causation means that cause-effect relationships are bi-directional, as a cause could later become an effect and vice versa. Such dynamic cause-effect relationships raise questions about the distinction between proximate and ultimate causes, as originally formulated by Ernst Mayr. They have also motivated some biologists and philosophers to argue for an Extended Evolutionary Synthesis (EES). The EES will supposedly expand the scope of the Modern Synthesis (MS) and SET, which has been characterized as gene-centred, relying primarily on natural selection and largely neglecting reciprocal causation. Here, I critically examine these claims, with a special focus on the last conjecture. I conclude that reciprocal causation has long been recognized as important by naturalists, ecologists and evolutionary biologists working in the in the MS tradition, although it it could be explored even further. Numerous empirical examples of reciprocal causation in the form of positive and negative feedback are now well known from both natural and laboratory systems. Reciprocal causation have also been explicitly incorporated in mathematical models of coevolutionary arms races, frequency-dependent selection, eco-evolutionary dynamics and sexual selection. Such dynamic feedback were already recognized by Richard Levins and Richard Lewontin in their bok The Dialectical Biologist . Reciprocal causation and dynamic feedback might also be one of the few contributions of dialectical thinking and Marxist philosophy in evolutionary theory. I discuss some promising empirical and analytical tools to study reciprocal causation and the implications for the EES. Finally, I briefly discuss how quantitative genetics can be adapated to studies of reciprocal causation, constructive inheritance and phenotypic plasticity and suggest that the flexibility of this approach

  5. A framework for evolutionary systems biology.

    Science.gov (United States)

    Loewe, Laurence

    2009-02-24

    Many difficult problems in evolutionary genomics are related to mutations that have weak effects on fitness, as the consequences of mutations with large effects are often simple to predict. Current systems biology has accumulated much data on mutations with large effects and can predict the properties of knockout mutants in some systems. However experimental methods are too insensitive to observe small effects. Here I propose a novel framework that brings together evolutionary theory and current systems biology approaches in order to quantify small effects of mutations and their epistatic interactions in silico. Central to this approach is the definition of fitness correlates that can be computed in some current systems biology models employing the rigorous algorithms that are at the core of much work in computational systems biology. The framework exploits synergies between the realism of such models and the need to understand real systems in evolutionary theory. This framework can address many longstanding topics in evolutionary biology by defining various 'levels' of the adaptive landscape. Addressed topics include the distribution of mutational effects on fitness, as well as the nature of advantageous mutations, epistasis and robustness. Combining corresponding parameter estimates with population genetics models raises the possibility of testing evolutionary hypotheses at a new level of realism. EvoSysBio is expected to lead to a more detailed understanding of the fundamental principles of life by combining knowledge about well-known biological systems from several disciplines. This will benefit both evolutionary theory and current systems biology. Understanding robustness by analysing distributions of mutational effects and epistasis is pivotal for drug design, cancer research, responsible genetic engineering in synthetic biology and many other practical applications.

  6. From computers to cultivation: reconceptualizing evolutionary psychology

    Directory of Open Access Journals (Sweden)

    Louise eBarrett

    2014-08-01

    Full Text Available Does evolutionary theorizing have a role in psychology? This is a more contentious issue than one might imagine, given that as evolved creatures, the answer must surely be yes. The contested nature of evolutionary psychology lies not in our status as evolved beings, but in the extent to which evolutionary ideas add value to studies of human behaviour, and the rigour with which these ideas are tested. This, in turn, is linked to the framework in which particular evolutionary ideas are situated. While the framing of the current research topic places the brain-as-computer metaphor in opposition to evolutionary psychology, the most prominent school of thought in this field (born out of cognitive psychology, and often known as the Santa Barbara school is entirely wedded to the computational theory of mind as an explanatory framework. Its unique aspect is to argue that the mind consists of a large number of functionally specialized (i.e., domain-specific computational mechanisms, or modules (the massive modularity hypothesis. Far from offering an alternative to, or an improvement on, the current perspective, we argue that evolutionary psychology is a mainstream computational theory, and that its arguments for domain-specificity often rest on shaky premises. We then go on to suggest that the various forms of e-cognition (i.e., embodied, embedded, enactive represent a true alternative to standard computational approaches, with an emphasis on cognitive integration or the extended mind hypothesis in particular. We feel this offers the most promise for human psychology because it incorporates the social and historical processes that are crucial to human ‘mind-making’ within an evolutionarily-informed framework. In addition to linking to other research areas in psychology, this approach is more likely to form productive links to other disciplines within the social sciences, not least by encouraging a healthy pluralism in approach.

  7. "Asia's missing women" as a problem in applied evolutionary psychology?

    Science.gov (United States)

    Brooks, Robert

    2012-12-20

    In many parts of Asia, the Middle East and North Africa, women and children are so undervalued, neglected, abused, and so often killed, that sex ratios are now strongly male biased. In recent decades, sex-biased abortion has exacerbated the problem. In this article I highlight several important insights from evolutionary biology into both the origin and the severe societal consequences of "Asia's missing women", paying particular attention to interactions between evolution, economics and culture. Son preferences and associated cultural practices like patrilineal inheritance, patrilocality and the Indian Hindu dowry system arise among the wealthy and powerful elites for reasons consistent with models of sex-biased parental investment. Those practices then spread via imitation as technology gets cheaper and economic development allows the middle class to grow rapidly. I will consider evidence from India, China and elsewhere that grossly male-biased sex ratios lead to increased crime, violence, local warfare, political instability, drug abuse, prostitution and trafficking of women. The problem of Asia's missing women presents a challenge for applied evolutionary psychology to help us understand and ameliorate sex ratio biases and their most severe consequences.

  8. Analysis of Evolutionary Processes of Species Jump in Waterfowl Parvovirus

    Science.gov (United States)

    Fan, Wentao; Sun, Zhaoyu; Shen, Tongtong; Xu, Danning; Huang, Kehe; Zhou, Jiyong; Song, Suquan; Yan, Liping

    2017-01-01

    Waterfowl parvoviruses are classified into goose parvovirus (GPV) and Muscovy duck parvovirus (MDPV) according to their antigenic features and host preferences. A novel duck parvovirus (NDPV), identified as a new variant of GPV, is currently infecting ducks, thus causing considerable economic loss. This study analyzed the molecular evolution and population dynamics of the emerging parvovirus capsid gene to investigate the evolutionary processes concerning the host shift of NDPV. Two important amino acids changes (Asn-489 and Asn-650) were identified in NDPV, which may be responsible for host shift of NDPV. Phylogenetic analysis indicated that the currently circulating NDPV originated from the GPV lineage. The Bayesian Markov chain Monte Carlo tree indicated that the NDPV diverged from GPV approximately 20 years ago. Evolutionary rate analyses demonstrated that GPV evolved with 7.674 × 10-4 substitutions/site/year, and the data for MDPV was 5.237 × 10-4 substitutions/site/year, whereas the substitution rate in NDPV branch was 2.25 × 10-3 substitutions/site/year. Meanwhile, viral population dynamics analysis revealed that the GPV major clade, including NDPV, grew exponentially at a rate of 1.717 year-1. Selection pressure analysis showed that most sites are subject to strong purifying selection and no positively selected sites were found in NDPV. The unique immune-epitopes in waterfowl parvovirus were also estimated, which may be helpful for the prediction of antibody binding sites against NDPV in ducks. PMID:28352261

  9. Clustering of protein domains for functional and evolutionary studies

    Directory of Open Access Journals (Sweden)

    Long Paul F

    2009-10-01

    Full Text Available Abstract Background The number of protein family members defined by DNA sequencing is usually much larger than those characterised experimentally. This paper describes a method to divide protein families into subtypes purely on sequence criteria. Comparison with experimental data allows an independent test of the quality of the clustering. Results An evolutionary split statistic is calculated for each column in a protein multiple sequence alignment; the statistic has a larger value when a column is better described by an evolutionary model that assumes clustering around two or more amino acids rather than a single amino acid. The user selects columns (typically the top ranked columns to construct a motif. The motif is used to divide the family into subtypes using a stochastic optimization procedure related to the deterministic annealing EM algorithm (DAEM, which yields a specificity score showing how well each family member is assigned to a subtype. The clustering obtained is not strongly dependent on the number of amino acids chosen for the motif. The robustness of this method was demonstrated using six well characterized protein families: nucleotidyl cyclase, protein kinase, dehydrogenase, two polyketide synthase domains and small heat shock proteins. Phylogenetic trees did not allow accurate clustering for three of the six families. Conclusion The method clustered the families into functional subtypes with an accuracy of 90 to 100%. False assignments usually had a low specificity score.

  10. On the evolutionary origins of the egalitarian syndrome.

    Science.gov (United States)

    Gavrilets, Sergey

    2012-08-28

    The evolutionary emergence of the egalitarian syndrome is one of the most intriguing unsolved puzzles related to the origins of modern humans. Standard explanations and models for cooperation and altruism--reciprocity, kin and group selection, and punishment--are not directly applicable to the emergence of egalitarian behavior in hierarchically organized groups that characterized the social life of our ancestors. Here I study an evolutionary model of group-living individuals competing for resources and reproductive success. In the model, the differences in fighting abilities lead to the emergence of hierarchies where stronger individuals take away resources from weaker individuals and, as a result, have higher reproductive success. First, I show that the logic of within-group competition implies under rather general conditions that each individual benefits if the transfer of the resource from a weaker group member to a stronger one is prevented. This effect is especially strong in small groups. Then I demonstrate that this effect can result in the evolution of a particular, genetically controlled psychology causing individuals to interfere in a bully-victim conflict on the side of the victim. A necessary condition is a high efficiency of coalitions in conflicts against the bullies. The egalitarian drive leads to a dramatic reduction in within-group inequality. Simultaneously it creates the conditions for the emergence of inequity aversion, empathy, compassion, and egalitarian moral values via the internalization of behavioral rules imposed by natural selection. It also promotes widespread cooperation via coalition formation.

  11. Physics of Strongly Coupled Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kraeft, Wolf-Dietrich [Universitat Rostock (Germany)

    2007-07-15

    Strongly coupled plasmas (or non-ideal plasmas) are multi-component charged many-particle systems, in which the mean value of the potential energy of the system is of the same order as or even higher than the mean value of the kinetic energy. The constituents are electrons, ions, atoms and molecules. Dusty (or complex) plasmas contain still mesoscopic (multiply charged) particles. In such systems, the effects of strong coupling (non-ideality) lead to considerable deviations of physical properties from the corresponding properties of ideal plasmas, i.e., of plasmas in which the mean kinetic energy is essentially larger than the mean potential energy. For instance, bound state energies become density dependent and vanish at higher densities (Mott effect) due to the interaction of the pair with the surrounding particles. Non-ideal plasmas are of interest both for general scientific reasons (including, for example, astrophysical questions), and for technical applications such as inertially confined fusion. In spite of great efforts both experimentally and theoretically, satisfactory information on the physical properties of strongly coupled plasmas is not at hand for any temperature and density. For example, the theoretical description of non-ideal plasmas is possible only at low densities/high temperatures and at extremely high densities (high degeneracy). For intermediate degeneracy, however, numerical experiments have to fill the gap. Experiments are difficult in the region of 'warm dense matter'. The monograph tries to present the state of the art concerning both theoretical and experimental attempts. It mainly includes results of the work performed in famous Russian laboratories in recent decades. After outlining basic concepts (chapter 1), the generation of plasmas is considered (chapter 2, chapter 3). Questions of partial (chapter 4) and full ionization (chapter 5) are discussed including Mott transition and Wigner crystallization. Electrical and

  12. Evolutionary cost management in the nuclear industry

    International Nuclear Information System (INIS)

    Lombardi, C.G.; Mazzini, R.A.

    1986-01-01

    The reader is urged to consider the material in ''The Evolutionary Theory of Cost Management'' carefully before proceeding with the material in this paper. The recommendations in this paper flow from the revised line of thinking generated by the evolutionary approach. The suggestions will be difficult to accept in the absence of an understanding of the underlying theory. Although the authors briefly discuss some of the theory, it is nevertheless recommended that the reader develop a fuller understanding of the concepts by studying the prior paper

  13. Evolutionary change in continuous reaction norms

    DEFF Research Database (Denmark)

    Murren, Courtney J; Maclean, Heidi J; Diamond, Sarah E

    2014-01-01

    Understanding the evolution of reaction norms remains a major challenge in ecology and evolution. Investigating evolutionary divergence in reaction norm shapes between populations and closely related species is one approach to providing insights. Here we use a meta-analytic approach to compare...... or species. These results show that evolutionary divergence of curvature is common and should be considered an important aspect of plasticity, together with slope. Biological details about traits and environments, including cryptic variation expressed in novel environmental conditions, may be critical...

  14. Evolutionary Graphs with Frequency Dependent Fitness

    Science.gov (United States)

    Nie, Pu-Yan; Zhang, Pei-Ai

    Evolutionary graph theory was recently proposed by Lieberman et al. in 2005. In the previous papers about evolutionary graphs (EGs), the fitness of the residents in the EGs is in general assumed to be unity, and the fitness of a mutant is assumed to be a constant r. We aim to extend EG to general cases in this paper, namely, the fitness of a mutant is heavily dependent upon frequency. The corresponding properties for these new EGs are analyzed, and the fixation probability is obtained for large population.

  15. Genomes, Phylogeny, and Evolutionary Systems Biology

    Energy Technology Data Exchange (ETDEWEB)

    Medina, Monica

    2005-03-25

    With the completion of the human genome and the growing number of diverse genomes being sequenced, a new age of evolutionary research is currently taking shape. The myriad of technological breakthroughs in biology that are leading to the unification of broad scientific fields such as molecular biology, biochemistry, physics, mathematics and computer science are now known as systems biology. Here I present an overview, with an emphasis on eukaryotes, of how the postgenomics era is adopting comparative approaches that go beyond comparisons among model organisms to shape the nascent field of evolutionary systems biology.

  16. Evolutionary dynamics of complex communications networks

    CERN Document Server

    Karyotis, Vasileios; Papavassiliou, Symeon

    2013-01-01

    Until recently, most network design techniques employed a bottom-up approach with lower protocol layer mechanisms affecting the development of higher ones. This approach, however, has not yielded fascinating results in the case of wireless distributed networks. Addressing the emerging aspects of modern network analysis and design, Evolutionary Dynamics of Complex Communications Networks introduces and develops a top-bottom approach where elements of the higher layer can be exploited in modifying the lowest physical topology-closing the network design loop in an evolutionary fashion similar to

  17. <strong>On Determinism in Modal Transition Systemsstrong>

    DEFF Research Database (Denmark)

    Benes, Nikola; Kretinsky, Jan; Larsen, Kim Guldstrand

    2009-01-01

    Modal transition systems (MTS) is a formalism which extends the classical notion of labelled transition systems by introducing transitions of two types: must transitions that have to be present in any implementation of the MTS and may transitions that are allowed but not required. The MTS framewo....... In the present article, we provide a comprehensive account of the MTS framework in the deterministic setting. We study a number of problems previously considered on MTS and point out to what extend we can expect better results under the restriction of determinism....

  18. Information behavior: an evolutionary instinct

    Directory of Open Access Journals (Sweden)

    Güler Demir

    2015-09-01

    Full Text Available The main purpose of this book is to develop a theoretical framework for the investigation of human information behavior within a multidisciplinary approach. Information behavior is not only instinctive with its social/cultural and cognitive dimensions, but is also a type of intelligence and a universal and biologically primary skill belonging to all of the people. It is thought that further researches are needed in order to clarify the process of information behavior which is such a complex process that cannot be fully understood only by contemporary and/or limited dimensions.

  19. Probability densities in strong turbulence

    Science.gov (United States)

    Yakhot, Victor

    2006-03-01

    In this work we, using Mellin’s transform combined with the Gaussian large-scale boundary condition, calculate probability densities (PDFs) of velocity increments P(δu,r), velocity derivatives P(u,r) and the PDF of the fluctuating dissipation scales Q(η,Re), where Re is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF P(δu,r) often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for the deviation of P(δu,r) from P(δu,r). An expression for the function D(h) of the multifractal theory, free from spurious logarithms recently discussed in [U. Frisch, M. Martins Afonso, A. Mazzino, V. Yakhot, J. Fluid Mech. 542 (2005) 97] is also obtained.

  20. Iris double recognition based on modified evolutionary neural network

    Science.gov (United States)

    Liu, Shuai; Liu, Yuan-Ning; Zhu, Xiao-Dong; Huo, Guang; Liu, Wen-Tao; Feng, Jia-Kai

    2017-11-01

    Aiming at multicategory iris recognition under illumination and noise interference, this paper proposes a method of iris double recognition based on a modified evolutionary neural network. An equalization histogram and Laplace of Gaussian operator are used to process the iris to suppress illumination and noise interference and Haar wavelet to convert the iris feature to binary feature encoding. Calculate the Hamming distance for the test iris and template iris , and compare with classification threshold, determine the type of iris. If the iris cannot be identified as a different type, there needs to be a secondary recognition. The connection weights in back-propagation (BP) neural network use modified evolutionary neural network to adaptively train. The modified neural network is composed of particle swarm optimization with mutation operator and BP neural network. According to different iris libraries in different circumstances of experimental results, under illumination and noise interference, the correct recognition rate of this algorithm is higher, the ROC curve is closer to the coordinate axis, the training and recognition time is shorter, and the stability and the robustness are better.