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Sample records for cellular darwinian evolution

  1. Darwinian evolution

    NARCIS (Netherlands)

    Jagers op Akkerhuis, Gerard A.J.M.; Spijkerboer, Hendrik Pieter; Koelewijn, Hans Peter

    2016-01-01

    Darwinian evolution is a central tenet in biology. Conventionally, the defi nition of Darwinian evolution is linked to a population-based process that can be measured by focusing on changes in DNA/allele frequencies. However, in some publications it has been suggested that selection represents a

  2. Darwinian evolution on a chip.

    Directory of Open Access Journals (Sweden)

    Brian M Paegel

    2008-04-01

    Full Text Available Computer control of Darwinian evolution has been demonstrated by propagating a population of RNA enzymes in a microfluidic device. The RNA population was challenged to catalyze the ligation of an oligonucleotide substrate under conditions of progressively lower substrate concentrations. A microchip-based serial dilution circuit automated an exponential growth phase followed by a 10-fold dilution, which was repeated for 500 log-growth iterations. Evolution was observed in real time as the population adapted and achieved progressively faster growth rates over time. The final evolved enzyme contained a set of 11 mutations that conferred a 90-fold improvement in substrate utilization, coinciding with the applied selective pressure. This system reduces evolution to a microfluidic algorithm, allowing the experimenter to observe and manipulate adaptation.

  3. Tumor progression: chance and necessity in Darwinian and Lamarckian somatic (mutationless) evolution.

    Science.gov (United States)

    Huang, Sui

    2012-09-01

    Current investigation of cancer progression towards increasing malignancy focuses on the molecular pathways that produce the various cancerous traits of cells. Their acquisition is explained by the somatic mutation theory: tumor progression is the result of a neo-Darwinian evolution in the tissue. Herein cells are the units of selection. Random genetic mutations permanently affecting these pathways create malignant cell phenotypes that are selected for in the disturbed tissue. However, could it be that the capacity of the genome and its gene regulatory network to generate the vast diversity of cell types during development, i.e., to produce inheritable phenotypic changes without mutations, is harnessed by tumorigenesis to propel a directional change towards malignancy? Here we take an encompassing perspective, transcending the orthodoxy of molecular carcinogenesis and review mechanisms of somatic evolution beyond the Neo-Darwinian scheme. We discuss the central concept of "cancer attractors" - the hidden stable states of gene regulatory networks normally not occupied by cells. Noise-induced transitions into such attractors provide a source for randomness (chance) and regulatory constraints (necessity) in the acquisition of novel expression profiles that can be inherited across cell divisions, and hence, can be selected for. But attractors can also be reached in response to environmental signals - thus offering the possibility for inheriting acquired traits that can also be selected for. Therefore, we face the possibility of non-genetic (mutation-independent) equivalents to both Darwinian and Lamarckian evolution which may jointly explain the arrow of change pointing toward increasing malignancy. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Diversification and enrichment of clinical biomaterials inspired by Darwinian evolution.

    Science.gov (United States)

    Green, D W; Watson, G S; Watson, J A; Lee, D-J; Lee, J-M; Jung, H-S

    2016-09-15

    Regenerative medicine and biomaterials design are driven by biomimicry. There is the essential requirement to emulate human cell, tissue, organ and physiological complexity to ensure long-lasting clinical success. Biomimicry projects for biomaterials innovation can be re-invigorated with evolutionary insights and perspectives, since Darwinian evolution is the original dynamic process for biological organisation and complexity. Many existing human inspired regenerative biomaterials (defined as a nature generated, nature derived and nature mimicking structure, produced within a biological system, which can deputise for, or replace human tissues for which it closely matches) are without important elements of biological complexity such as, hierarchy and autonomous actions. It is possible to engineer these essential elements into clinical biomaterials via bioinspired implementation of concepts, processes and mechanisms played out during Darwinian evolution; mechanisms such as, directed, computational, accelerated evolutions and artificial selection contrived in the laboratory. These dynamos for innovation can be used during biomaterials fabrication, but also to choose optimal designs in the regeneration process. Further evolutionary information can help at the design stage; gleaned from the historical evolution of material adaptations compared across phylogenies to changes in their environment and habitats. Taken together, harnessing evolutionary mechanisms and evolutionary pathways, leading to ideal adaptations, will eventually provide a new class of Darwinian and evolutionary biomaterials. This will provide bioengineers with a more diversified and more efficient innovation tool for biomaterial design, synthesis and function than currently achieved with synthetic materials chemistry programmes and rational based materials design approach, which require reasoned logic. It will also inject further creativity, diversity and richness into the biomedical technologies that

  5. Is evolution Darwinian or/and Lamarckian?

    Directory of Open Access Journals (Sweden)

    Wolf Yuri I

    2009-11-01

    Full Text Available Abstract Background The year 2009 is the 200th anniversary of the publication of Jean-Bapteste Lamarck's Philosophie Zoologique and the 150th anniversary of Charles Darwin's On the Origin of Species. Lamarck believed that evolution is driven primarily by non-randomly acquired, beneficial phenotypic changes, in particular, those directly affected by the use of organs, which Lamarck believed to be inheritable. In contrast, Darwin assigned a greater importance to random, undirected change that provided material for natural selection. The concept The classic Lamarckian scheme appears untenable owing to the non-existence of mechanisms for direct reverse engineering of adaptive phenotypic characters acquired by an individual during its life span into the genome. However, various evolutionary phenomena that came to fore in the last few years, seem to fit a more broadly interpreted (quasiLamarckian paradigm. The prokaryotic CRISPR-Cas system of defense against mobile elements seems to function via a bona fide Lamarckian mechanism, namely, by integrating small segments of viral or plasmid DNA into specific loci in the host prokaryote genome and then utilizing the respective transcripts to destroy the cognate mobile element DNA (or RNA. A similar principle seems to be employed in the piRNA branch of RNA interference which is involved in defense against transposable elements in the animal germ line. Horizontal gene transfer (HGT, a dominant evolutionary process, at least, in prokaryotes, appears to be a form of (quasiLamarckian inheritance. The rate of HGT and the nature of acquired genes depend on the environment of the recipient organism and, in some cases, the transferred genes confer a selective advantage for growth in that environment, meeting the Lamarckian criteria. Various forms of stress-induced mutagenesis are tightly regulated and comprise a universal adaptive response to environmental stress in cellular life forms. Stress-induced mutagenesis

  6. Non-Darwinian evolution for the source detection of atmospheric releases

    Science.gov (United States)

    Cervone, Guido; Franzese, Pasquale

    2011-08-01

    A non-Darwinian evolutionary algorithm is presented as search engine to identify the characteristics of a source of atmospheric pollutants, given a set of concentration measurements. The algorithm drives iteratively a forward dispersion model from tentative sources toward the real source. The solutions of non-Darwinian evolution processes are not generated through pseudo-random operators, unlike traditional evolutionary algorithms, but through a reasoning process based on machine learning rule generation and instantiation. The new algorithm is tested with both a synthetic case and with the Prairie Grass field experiment. To further test the capabilities of the algorithm to work in real-world scenarios, the source identification of all Prairie Grass releases was performed with a decreasing number of sensor measurements, and a relationship is found between the precision of the solution, the number of sensors available, and the levels of concentration measured by the sensors. The proposed methodology can be used for a variety of optimization problems, and is particularly suited for problems where the operations needed for evaluating new candidate solutions are computationally expensive.

  7. Modeling evolution and immune system by cellular automata

    International Nuclear Information System (INIS)

    Bezzi, M.

    2001-01-01

    In this review the behavior of two different biological systems is investigated using cellular automata. Starting from this spatially extended approach it is also tried, in some cases, to reduce the complexity of the system introducing mean-field approximation, and solving (or trying to solve) these simplified systems. It is discussed the biological meaning of the results, the comparison with experimental data (if available) and the different features between spatially extended and mean-field versions. The biological systems considered in this review are the following: Darwinian evolution in simple ecosystems and immune system response. In the first section the main features of molecular evolution are introduced, giving a short survey of genetics for physicists and discussing some models for prebiotic systems and simple ecosystems. It is also introduced a cellular automaton model for studying a set of evolving individuals in a general fitness landscape, considering also the effects of co-evolution. In particular the process of species formation (speciation) is described in sect. 5. The second part deals with immune system modeling. The biological features of immune response are discussed, as well as it is introduced the concept of shape space and of idiotypic network. More detailed reviews which deal with immune system models (mainly focused on idiotypic network models) can be found. Other themes here discussed: the applications of CA to immune system modeling, two complex cellular automata for humoral and cellular immune response. Finally, it is discussed the biological data and the general conclusions are drawn in the last section

  8. If we are all cultural Darwinians what's the fuss about? : clarifying recent disagreements in the field of cultural evolution

    NARCIS (Netherlands)

    Acerbi, A.; Mesoudi, A.

    2015-01-01

    Cultural evolution studies are characterized by the notion that culture evolves accordingly to broadly Darwinian principles. Yet how far the analogy between cultural and genetic evolution should be pushed is open to debate. Here, we examine a recent disagreement that concerns the extent to which

  9. Adaptive evolution of cooperation through Darwinian dynamics in Public Goods games.

    Science.gov (United States)

    Deng, Kuiying; Chu, Tianguang

    2011-01-01

    The linear or threshold Public Goods game (PGG) is extensively accepted as a paradigmatic model to approach the evolution of cooperation in social dilemmas. Here we explore the significant effect of nonlinearity of the structures of public goods on the evolution of cooperation within the well-mixed population by adopting Darwinian dynamics, which simultaneously consider the evolution of populations and strategies on a continuous adaptive landscape, and extend the concept of evolutionarily stable strategy (ESS) as a coalition of strategies that is both convergent-stable and resistant to invasion. Results show (i) that in the linear PGG contributing nothing is an ESS, which contradicts experimental data, (ii) that in the threshold PGG contributing the threshold value is a fragile ESS, which cannot resist the invasion of contributing nothing, and (iii) that there exists a robust ESS of contributing more than half in the sigmoid PGG if the return rate is relatively high. This work reveals the significant effect of the nonlinearity of the structures of public goods on the evolution of cooperation, and suggests that, compared with the linear or threshold PGG, the sigmoid PGG might be a more proper model for the evolution of cooperation within the well-mixed population.

  10. What makes Darwinian hydrology "Darwinian"? Asking a different kind of question about landscapes

    Science.gov (United States)

    Harman, C.; Troch, P. A.

    2014-02-01

    There have been repeated calls for a Darwinian approach to hydrologic science, or for a synthesis of Darwinian and Newtonian approaches, to deepen understanding of the hydrologic system in the larger landscape context, and so develop a better basis for predictions now and in an uncertain future. But what exactly makes a Darwinian approach to hydrology "Darwinian"? While there have now been a number of discussions of Darwinian approaches, many referencing Harte (2002), the term is potentially a source of confusion because its connections to Darwin remain allusive rather than explicit. Here we suggest that the Darwinian approach to hydrology follows the example of Charles Darwin by focusing attention on the patterns of variation in populations and seeking hypotheses that explain these patterns in terms of the mechanisms and conditions that determine their historical development. These hypotheses do not simply catalog patterns or predict them statistically - they connect the present structure with processes operating in the past. Nor are they explanations presented without independent evidence or critical analysis - Darwin's hypotheses about the mechanisms underlying present-day variation could be independently tested and validated. With a Darwinian framework in mind, it is easy to see that a great deal of hydrologic research has already been done that contributes to a Darwinian hydrology - whether deliberately or not. We discuss some practical and philosophical issues with this approach to hydrologic science: how are explanatory hypotheses generated? What constitutes a good hypothesis? How are hypotheses tested? "Historical" sciences - including paleohydrology - have long grappled with these questions, as must a Darwinian hydrologic science. We can draw on Darwin's own example for some answers, though there are ongoing debates about the philosophical nature of his methods and reasoning. Darwin used a range of methods of historical reasoning to develop explanatory

  11. The Problem with a Darwinian View of Humanity

    Science.gov (United States)

    Cunningham, Paul F.

    2009-01-01

    Comments on the special issue on Charles Darwin and psychology (Dewsbury, February-March 2009), in which the authors present evidence supporting the validity of Charles Darwin's theory of evolution and how generations of psychologists have viewed the natural world through its light, taking Darwinian theories for granted as being a literal…

  12. Extending and expanding the Darwinian synthesis: the role of complex systems dynamics.

    Science.gov (United States)

    Weber, Bruce H

    2011-03-01

    Darwinism is defined here as an evolving research tradition based upon the concepts of natural selection acting upon heritable variation articulated via background assumptions about systems dynamics. Darwin's theory of evolution was developed within a context of the background assumptions of Newtonian systems dynamics. The Modern Evolutionary Synthesis, or neo-Darwinism, successfully joined Darwinian selection and Mendelian genetics by developing population genetics informed by background assumptions of Boltzmannian systems dynamics. Currently the Darwinian Research Tradition is changing as it incorporates new information and ideas from molecular biology, paleontology, developmental biology, and systems ecology. This putative expanded and extended synthesis is most perspicuously deployed using background assumptions from complex systems dynamics. Such attempts seek to not only broaden the range of phenomena encompassed by the Darwinian Research Tradition, such as neutral molecular evolution, punctuated equilibrium, as well as developmental biology, and systems ecology more generally, but to also address issues of the emergence of evolutionary novelties as well as of life itself. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Quantum Darwinism as a Darwinian process

    OpenAIRE

    Campbell, John

    2010-01-01

    The Darwinian nature of Wojciech Zurek's theory of Quantum Darwinism is evaluated against the criteria of a Darwinian process as understood within Universal Darwinism. The characteristics of a Darwinian process are developed including the consequences of accumulated adaptations resulting in adaptive systems operating in accordance with Friston's free energy principle and employing environmental simulations. Quantum theory, as developed in Zurek's research program and encapsulated by his theor...

  14. Alfred Russel Wallace (1823-1913): the forgotten co-founder of the Neo-Darwinian theory of biological evolution.

    Science.gov (United States)

    Kutschera, Ulrich; Hossfeld, Uwe

    2013-12-01

    The British naturalist Alfred Russel Wallace (1823-1913), who had to leave school aged 14 and never attended university, did extensive fieldwork, first in the Amazon River basin (1848-1852) and then in Southeast Asia (1854-1862). Based on this experience, and after reading the corresponding scientific literature, Wallace postulated that species were not created, but are modified descendants of pre-existing varieties (Sarawak Law paper, 1855). Evolution is brought about by a struggle for existence via natural selection, which results in the adaptation of those individuals in variable populations who survive and reproduce (Ternate essay, 1858). In his monograph Darwinism (1889), and in subsequent publications, Wallace extended the contents of Darwin's Origin of Species (1859) into the Neo-Darwinian theory of biological evolution, with reference to the work of August Weismann (1834-1914). Wallace also became the (co)-founder of biogeography, biodiversity research, astrobiology and evolutionary anthropology. Moreover, he envisioned what was later called the anthropocene (i.e., the age of human environmental destructiveness). However, since Wallace believed in atheistic spiritualism and mixed up scientific facts and supernatural speculations in some of his writings, he remains a controversial figure in the history of biology.

  15. The relativity of Darwinian populations and the ecology of endosymbiosis.

    Science.gov (United States)

    Stencel, Adrian

    If there is a single discipline of science calling the basic concepts of biology into question, it is without doubt microbiology. Indeed, developments in microbiology have recently forced us to rethink such fundamental concepts as the organism, individual, and genome. In this paper I show how microorganisms are changing our understanding of natural aggregations and develop the concept of a Darwinian population to embrace these discoveries. I start by showing that it is hard to set the boundaries of a Darwinian population, and I suggest thinking of a Darwinian population as a relative property of a Darwinian individual. Then I argue, in contrast to the commonly held view, that Darwinian populations are multispecies units, and that in order to accept the multispecies account of Darwinian populations we have to separate fitness from natural selection. Finally, I show how all these ideas provide a theoretical framework leading to a more precise understanding of the ecology of endosymbiosis than is afforded by poetic metaphors such as 'slavery'.

  16. Darwinian Model Building

    NARCIS (Netherlands)

    Kester, Do; Bontekoe, Romke; MohammadDjafari, A; Bercher, JF; Bessiere, P

    2010-01-01

    We present a way to generate heuristic mathematical models based on the Darwinian principles of variation and selection in a pool of individuals over many generations. Each individual has a genotype (the hereditary properties) and a phenotype (the expression of these properties in the environment).

  17. The Mastodon in the room: how Darwinian is neo-Darwinism?

    Science.gov (United States)

    Brooks, Daniel R

    2011-03-01

    Failing to acknowledge substantial differences between Darwinism and neo-Darwinism impedes evolutionary biology. Darwin described evolution as the outcome of interactions between the nature of the organism and the nature of the conditions, each relatively autonomous but both historically and spatially intertwined. Furthermore, he postulated that the nature of the organism was more important than the nature of the conditions, leading to natural selection as an inevitable emergent product of biological systems. The neo-Darwinian tradition assumed a creative rather than selective view of natural selection, with the nature of the organism determined by the nature of the conditions, rendering the nature of the organism and temporal contingency unnecessary. Contemporary advances in biology, specifically the phylogenetics revolution and evo-devo, underscore the significance of history and the nature of the organism in biology. Darwinism explains more biology better, and better resolves apparent anomalies between living systems and more general natural laws, than does neo-Darwinism. The "extended" or "expanded" synthesis currently called for by neo-Darwinians is Darwinism. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Toward the Darwinian transition: Switching between distributed and speciated states in a simple model of early life.

    Science.gov (United States)

    Arnoldt, Hinrich; Strogatz, Steven H; Timme, Marc

    2015-01-01

    It has been hypothesized that in the era just before the last universal common ancestor emerged, life on earth was fundamentally collective. Ancient life forms shared their genetic material freely through massive horizontal gene transfer (HGT). At a certain point, however, life made a transition to the modern era of individuality and vertical descent. Here we present a minimal model for stochastic processes potentially contributing to this hypothesized "Darwinian transition." The model suggests that HGT-dominated dynamics may have been intermittently interrupted by selection-driven processes during which genotypes became fitter and decreased their inclination toward HGT. Stochastic switching in the population dynamics with three-point (hypernetwork) interactions may have destabilized the HGT-dominated collective state and essentially contributed to the emergence of vertical descent and the first well-defined species in early evolution. A systematic nonlinear analysis of the stochastic model dynamics covering key features of evolutionary processes (such as selection, mutation, drift and HGT) supports this view. Our findings thus suggest a viable direction out of early collective evolution, potentially enabling the start of individuality and vertical Darwinian evolution.

  19. A model of epigenetic evolution based on theory of open quantum systems.

    Science.gov (United States)

    Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Tanaka, Yoshiharu; Yamato, Ichiro

    2013-12-01

    We present a very general model of epigenetic evolution unifying (neo-)Darwinian and (neo-)Lamarckian viewpoints. The evolution is represented in the form of adaptive dynamics given by the quantum(-like) master equation. This equation describes development of the information state of epigenome under the pressure of an environment. We use the formalism of quantum mechanics in the purely operational framework. (Hence, our model has no direct relation to quantum physical processes inside a cell.) Thus our model is about probabilities for observations which can be done on epigenomes and it does not provide a detailed description of cellular processes. Usage of the operational approach provides a possibility to describe by one model all known types of cellular epigenetic inheritance.

  20. Darwinian hydrology: can the methodology Charles Darwin pioneered help hydrologic science?

    Science.gov (United States)

    Harman, C.; Troch, P. A.

    2013-05-01

    There have been repeated calls for a Darwinian approach to hydrologic science or for a synthesis of Darwinian and Newtonian approaches, to deepen understanding the hydrologic system in the larger landscape context, and so develop a better basis for predictions now and in an uncertain future. But what exactly makes a Darwinian approach to hydrology "Darwinian"? While there have now been a number of discussions of Darwinian approaches, many referencing Harte (2002), the term is potentially a source of confusion while its connections to Darwin remain allusive rather than explicit. Here we discuss the methods that Charles Darwin pioneered to understand a variety of complex systems in terms of their historical processes of change. We suggest that the Darwinian approach to hydrology follows his lead by focusing attention on the patterns of variation in populations, seeking hypotheses that explain these patterns in terms of the mechanisms and conditions that determine their historical development, using deduction and modeling to derive consequent hypotheses that follow from a proposed explanation, and critically testing these hypotheses against new observations. It is not sufficient to catalogue the patterns or predict them statistically. Nor is it sufficient for the explanations to amount to a "just-so" story not subject to critical analysis. Darwin's theories linked present-day variation to mechanisms that operated over history, and could be independently test and falsified by comparing new observations to the predictions of corollary hypotheses they generated. With a Darwinian framework in mind it is easy to see that a great deal of hydrologic research has already been done that contributes to a Darwinian hydrology - whether deliberately or not. The various heuristic methods that Darwin used to develop explanatory theories - extrapolating mechanisms, space for time substitution, and looking for signatures of history - have direct application in hydrologic science. Some

  1. Nonequilibrium Entropic Bounds for Darwinian Replicators

    Directory of Open Access Journals (Sweden)

    Jordi Piñero

    2018-01-01

    Full Text Available Life evolved on our planet by means of a combination of Darwinian selection and innovations leading to higher levels of complexity. The emergence and selection of replicating entities is a central problem in prebiotic evolution. Theoretical models have shown how populations of different types of replicating entities exclude or coexist with other classes of replicators. Models are typically kinetic, based on standard replicator equations. On the other hand, the presence of thermodynamical constraints for these systems remain an open question. This is largely due to the lack of a general theory of statistical methods for systems far from equilibrium. Nonetheless, a first approach to this problem has been put forward in a series of novel developements falling under the rubric of the extended second law of thermodynamics. The work presented here is twofold: firstly, we review this theoretical framework and provide a brief description of the three fundamental replicator types in prebiotic evolution: parabolic, malthusian and hyperbolic. Secondly, we employ these previously mentioned techinques to explore how replicators are constrained by thermodynamics. Finally, we comment and discuss where further research should be focused on.

  2. Chemical evolution and life

    Directory of Open Access Journals (Sweden)

    Malaterre Christophe

    2015-01-01

    Full Text Available In research on the origins of life, the concept of “chemical evolution” aims at explaining the transition from non-living matter to living matter. There is however strong disagreement when it comes to defining this concept more precisely, and in particular with reference to a chemical form of Darwinian evolution: for some, chemical evolution is nothing but Darwinian evolution applied to chemical systems before life appeared; yet, for others, it is the type of evolution that happened before natural selection took place, the latter being the birthmark of living systems. In this contribution, I review the arguments defended by each side and show how both views presuppose a dichotomous definition of “life”.

  3. Quantitative Imaging in Cancer Evolution and Ecology

    Science.gov (United States)

    Grove, Olya; Gillies, Robert J.

    2013-01-01

    Cancer therapy, even when highly targeted, typically fails because of the remarkable capacity of malignant cells to evolve effective adaptations. These evolutionary dynamics are both a cause and a consequence of cancer system heterogeneity at many scales, ranging from genetic properties of individual cells to large-scale imaging features. Tumors of the same organ and cell type can have remarkably diverse appearances in different patients. Furthermore, even within a single tumor, marked variations in imaging features, such as necrosis or contrast enhancement, are common. Similar spatial variations recently have been reported in genetic profiles. Radiologic heterogeneity within tumors is usually governed by variations in blood flow, whereas genetic heterogeneity is typically ascribed to random mutations. However, evolution within tumors, as in all living systems, is subject to Darwinian principles; thus, it is governed by predictable and reproducible interactions between environmental selection forces and cell phenotype (not genotype). This link between regional variations in environmental properties and cellular adaptive strategies may permit clinical imaging to be used to assess and monitor intratumoral evolution in individual patients. This approach is enabled by new methods that extract, report, and analyze quantitative, reproducible, and mineable clinical imaging data. However, most current quantitative metrics lack spatialness, expressing quantitative radiologic features as a single value for a region of interest encompassing the whole tumor. In contrast, spatially explicit image analysis recognizes that tumors are heterogeneous but not well mixed and defines regionally distinct habitats, some of which appear to harbor tumor populations that are more aggressive and less treatable than others. By identifying regional variations in key environmental selection forces and evidence of cellular adaptation, clinical imaging can enable us to define intratumoral

  4. Definition and evolution of quantum cellular automata with two qubits per cell

    International Nuclear Information System (INIS)

    Karafyllidis, Ioannis G.

    2004-01-01

    Studies of quantum computer implementations suggest cellular quantum computer architectures. These architectures can simulate the evolution of quantum cellular automata, which can possibly simulate both quantum and classical physical systems and processes. It is however known that except for the trivial case, unitary evolution of one-dimensional homogeneous quantum cellular automata with one qubit per cell is not possible. Quantum cellular automata that comprise two qubits per cell are defined and their evolution is studied using a quantum computer simulator. The evolution is unitary and its linearity manifests itself as a periodic structure in the probability distribution patterns

  5. Luria-Delbrück, revisited: the classic experiment does not rule out Lamarckian evolution

    Science.gov (United States)

    Holmes, Caroline M.; Ghafari, Mahan; Abbas, Anzar; Saravanan, Varun; Nemenman, Ilya

    2017-10-01

    We re-examined data from the classic Luria-Delbrück fluctuation experiment, which is often credited with establishing a Darwinian basis for evolution. We argue that, for the Lamarckian model of evolution to be ruled out by the experiment, the experiment must favor pure Darwinian evolution over both the Lamarckian model and a model that allows both Darwinian and Lamarckian mechanisms (as would happen for bacteria with CRISPR-Cas immunity). Analysis of the combined model was not performed in the original 1943 paper. The Luria-Delbrück paper also did not consider the possibility of neither model fitting the experiment. Using Bayesian model selection, we find that the Luria-Delbrück experiment, indeed, favors the Darwinian evolution over purely Lamarckian. However, our analysis does not rule out the combined model, and hence cannot rule out Lamarckian contributions to the evolutionary dynamics.

  6. Do Galaxies Follow Darwinian Evolution?

    Science.gov (United States)

    2006-12-01

    Using VIMOS on ESO's Very Large Telescope, a team of French and Italian astronomers have shown the strong influence the environment exerts on the way galaxies form and evolve. The scientists have for the first time charted remote parts of the Universe, showing that the distribution of galaxies has considerably evolved with time, depending on the galaxies' immediate surroundings. This surprising discovery poses new challenges for theories of the formation and evolution of galaxies. The 'nature versus nurture' debate is a hot topic in human psychology. But astronomers too face similar conundrums, in particular when trying to solve a problem that goes to the very heart of cosmological theories: are the galaxies we see today simply the product of the primordial conditions in which they formed, or did experiences in the past change the path of their evolution? ESO PR Photo 17/06 ESO PR Photo 45/06 Galaxy Distribution in Space In a large, three-year long survey carried out with VIMOS [1], the Visible Imager and Multi-Object Spectrograph on ESO's VLT, astronomers studied more than 6,500 galaxies over a wide range of distances to investigate how their properties vary over different timescales, in different environments and for varying galaxy luminosities [2]. They were able to build an atlas of the Universe in three dimensions, going back more than 9 billion years. This new census reveals a surprising result. The colour-density relation, that describes the relationship between the properties of a galaxy and its environment, was markedly different 7 billion years ago. The astronomers thus found that the galaxies' luminosity, their initial genetic properties, and the environments they reside in have a profound impact on their evolution. "Our results indicate that environment is a key player in galaxy evolution, but there's no simple answer to the 'nature versus nurture' problem in galaxy evolution," said Olivier Le Fèvre from the Laboratoire d'Astrophysique de Marseille

  7. Darwinian Controversies: An Historiographical Recounting

    Science.gov (United States)

    Depew, David J.

    2010-05-01

    This essay reviews key controversies in the history of the Darwinian research tradition: the Wilberforce-Huxley debate in 1860, early twentieth-century debates about the heritability of acquired characteristics and the consistency of Mendelian genetics with natural selection; the 1925 Scopes trial about teaching evolution; tensions about race, culture, and eugenics at the 1959 centenary celebration Darwin’s Origin of Species; adaptationism and its critics in the Sociobiology debate of 1970s and, more recently, Evolutionary Psychology; and current disputes about Intelligent Design. These controversies, I argue, are etched into public memory because they occur at the emotionally charged boundaries between public-political, technical-scientific, and personal-religious spheres of discourse. Over most of them falls the shadow of eugenics. The main lesson is that the history of Darwinism cannot be told except by showing the mutual influence of the different norms of discourse that obtain in the personal, technical, and public spheres. Nor can evolutionary biology successfully be taught to citizens and citizens-to-be until the fractious intersections between spheres of discourse have been made explicit. In the course of showing why, I take rival evolutionary approaches to be dynamical historical research traditions rather than static theories. Accordingly, I distinguish Darwin’s version of Darwinism from its later transformations. I pay special attention to the role Darwin assigned to development in evolution, which was marginalized by twentieth-century population genetical Darwinism, but has recently resurfaced in new forms. I also show how the disputed phrases “survival of the fittest” and “social Darwinism” have shaped personal anxieties about “Darwinism,” have provoked public opposition to teaching evolution in public schools, and have cast a shadow over efforts to effectively communicate to the public largely successful technical efforts to make

  8. Evolution and transitions in complexity

    NARCIS (Netherlands)

    Jagers op Akkerhuis, Gerard A.J.M.

    2016-01-01

    This book discusses several recent theoretic advancements in interdisciplinary and transdisciplinary integration in the field of evolution. While exploring novel views, the text maintains a close link with one of the most broadly held views on evolution, namely that of "Darwinian evolution." This

  9. Chemical Evolution and the Evolutionary Definition of Life.

    Science.gov (United States)

    Higgs, Paul G

    2017-06-01

    Darwinian evolution requires a mechanism for generation of diversity in a population, and selective differences between individuals that influence reproduction. In biology, diversity is generated by mutations and selective differences arise because of the encoded functions of the sequences (e.g., ribozymes or proteins). Here, I draw attention to a process that I will call chemical evolution, in which the diversity is generated by random chemical synthesis instead of (or in addition to) mutation, and selection acts on physicochemical properties, such as hydrolysis, photolysis, solubility, or surface binding. Chemical evolution applies to short oligonucleotides that can be generated by random polymerization, as well as by template-directed replication, and which may be too short to encode a specific function. Chemical evolution is an important stage on the pathway to life, between the stage of "just chemistry" and the stage of full biological evolution. A mathematical model is presented here that illustrates the differences between these three stages. Chemical evolution leads to much larger differences in molecular concentrations than can be achieved by selection without replication. However, chemical evolution is not open-ended, unlike biological evolution. The ability to undergo Darwinian evolution is often considered to be a defining feature of life. Here, I argue that chemical evolution, although Darwinian, does not quite constitute life, and that a good place to put the conceptual boundary between non-life and life is between chemical and biological evolution.

  10. Protein Based Molecular Markers Provide Reliable Means to Understand Prokaryotic Phylogeny and Support Darwinian Mode of Evolution

    Directory of Open Access Journals (Sweden)

    Vaibhav eBhandari

    2012-07-01

    Full Text Available The analyses of genome sequences have led to the proposal that lateral gene transfers (LGTs among prokaryotes are so widespread that they disguise the interrelationships among these organisms. This has led to questioning whether the Darwinian model of evolution is applicable to the prokaryotic organisms. In this review, we discuss the usefulness of taxon-specific molecular markers such as conserved signature indels (CSIs and conserved signature proteins (CSPs for understanding the evolutionary relationships among prokaryotes and to assess the influence of LGTs on prokaryotic evolution. The analyses of genomic sequences have identified large numbers of CSIs and CSPs that are unique properties of different groups of prokaryotes ranging from phylum to genus levels. The species distribution patterns of these molecular signatures strongly support a tree-like vertical inheritance of the genes containing these molecular signatures that is consistent with phylogenetic trees. Recent detailed studies in this regard on Thermotogae and Archaea, which are reviewed here, have identified large numbers of CSIs and CSPs that are specific for the species from these two taxa and a number of their major clades. The genetic changes responsible for these CSIs (and CSPs initially likely occurred in the common ancestors of these taxa and then vertically transferred to various descendants. Although some CSIs and CSPs in unrelated groups of prokaryotes were identified, their small numbers and random occurrence has no apparent influence on the consistent tree-like branching pattern emerging from other markers. These results provide evidence that although LGT is an important evolutionary force, it does not mask the tree-like branching pattern of prokaryotes or understanding of their evolutionary relationships. The identified CSIs and CSPs also provide novel and highly specific means for identification of different groups of microbes and for taxonomical and biochemical

  11. Protein based molecular markers provide reliable means to understand prokaryotic phylogeny and support Darwinian mode of evolution.

    Science.gov (United States)

    Bhandari, Vaibhav; Naushad, Hafiz S; Gupta, Radhey S

    2012-01-01

    The analyses of genome sequences have led to the proposal that lateral gene transfers (LGTs) among prokaryotes are so widespread that they disguise the interrelationships among these organisms. This has led to questioning of whether the Darwinian model of evolution is applicable to prokaryotic organisms. In this review, we discuss the usefulness of taxon-specific molecular markers such as conserved signature indels (CSIs) and conserved signature proteins (CSPs) for understanding the evolutionary relationships among prokaryotes and to assess the influence of LGTs on prokaryotic evolution. The analyses of genomic sequences have identified large numbers of CSIs and CSPs that are unique properties of different groups of prokaryotes ranging from phylum to genus levels. The species distribution patterns of these molecular signatures strongly support a tree-like vertical inheritance of the genes containing these molecular signatures that is consistent with phylogenetic trees. Recent detailed studies in this regard on the Thermotogae and Archaea, which are reviewed here, have identified large numbers of CSIs and CSPs that are specific for the species from these two taxa and a number of their major clades. The genetic changes responsible for these CSIs (and CSPs) initially likely occurred in the common ancestors of these taxa and then vertically transferred to various descendants. Although some CSIs and CSPs in unrelated groups of prokaryotes were identified, their small numbers and random occurrence has no apparent influence on the consistent tree-like branching pattern emerging from other markers. These results provide evidence that although LGT is an important evolutionary force, it does not mask the tree-like branching pattern of prokaryotes or understanding of their evolutionary relationships. The identified CSIs and CSPs also provide novel and highly specific means for identification of different groups of microbes and for taxonomical and biochemical studies.

  12. Cellular packing, mechanical stress and the evolution of multicellularity

    Science.gov (United States)

    Jacobeen, Shane; Pentz, Jennifer T.; Graba, Elyes C.; Brandys, Colin G.; Ratcliff, William C.; Yunker, Peter J.

    2018-03-01

    The evolution of multicellularity set the stage for sustained increases in organismal complexity1-5. However, a fundamental aspect of this transition remains largely unknown: how do simple clusters of cells evolve increased size when confronted by forces capable of breaking intracellular bonds? Here we show that multicellular snowflake yeast clusters6-8 fracture due to crowding-induced mechanical stress. Over seven weeks ( 291 generations) of daily selection for large size, snowflake clusters evolve to increase their radius 1.7-fold by reducing the accumulation of internal stress. During this period, cells within the clusters evolve to be more elongated, concomitant with a decrease in the cellular volume fraction of the clusters. The associated increase in free space reduces the internal stress caused by cellular growth, thus delaying fracture and increasing cluster size. This work demonstrates how readily natural selection finds simple, physical solutions to spatial constraints that limit the evolution of group size—a fundamental step in the evolution of multicellularity.

  13. A good Darwinian? Winwood Reade and the making of a late Victorian evolutionary epic.

    Science.gov (United States)

    Hesketh, Ian

    2015-06-01

    In 1871 the travel writer and anthropologist W. Winwood Reade (1838-1875) was inspired by his correspondence with Darwin to turn his narrow ethnological research on West African tribes into the broadest history imaginable, one that would show Darwin's great principle of natural selection at work throughout the evolutionary history of humanity, stretching back to the origins of the universe itself. But when Martyrdom of Man was published in 1872, Reade confessed that Darwin would not likely find him a very good Darwinian, as he was unable to show that natural selection was anything more than a secondary law that arranges all details. When it came to historicising humans within the sweeping history of all creation, Reade argued that the primary law was that of development, a less contentious theory of human evolution that was better suited to Reade's progressive and teleological history of life. By focussing on the extensive correspondence between Reade and Darwin, this paper reconstructs the attempt to make an explicitly Darwinian evolutionary epic in order to shed light on the moral and aesthetic demands that worked to give shape to Victorian efforts to historicise humans within a vastly expanding timeframe. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. EUGENICS, THE GIRARDIAN THEORY OF SACRIFICE, AND THE NEW DARWINIAN ETHICS

    Directory of Open Access Journals (Sweden)

    THOMAS RYBA

    2011-11-01

    Full Text Available In this paper I argue that, though many ethical systems recognizesacrifice as moral action, the utilitarian appropriation of Neo-Darwinian theory especially as it justifies eugenics as a “winnowing of the human stock” is in Girardian terms analogous to the sacrificial scapegoating of innocents. This argument is accomplished in four steps. (1 I show that within some ethical systems sacrifice is recognized as moral behavior driven by a specific axiology (or theory of value (2 I discuss some of the meta-ethical problems connected with Neo-Darwinian naturalism and naturalism, in general. (3 I show how modern varieties of naturalism and Darwinian naturalism, inparticular are especially inclined to lead to a moral justification of eugenic scapegoating and how Girardian theory is helpful in identifying the moral disorder connected with eugenics. (4 Finally, I conclude by arguing that Darwin’s thought is susceptible to another kind of interpretation, one that need not lead to the valorization of eugenics.

  15. Direct Measurements of Human Colon Crypt Stem Cell Niche Genetic Fidelity: The Role of Chance in Non-Darwinian Mutation Selection

    Directory of Open Access Journals (Sweden)

    Haeyoun eKang

    2013-10-01

    Full Text Available Perfect human stem cell genetic fidelity would prevent aging and cancer. However, perfection would be difficult to achieve, and aging is universal and cancers common. A hypothesis is that because mutations are inevitable over a human lifetime, downstream mechanisms have evolved to manage the deleterious effects of beneficial and lethal mutations. In the colon, a crypt stem cell architecture reduces the number of mitotic cells at risk for mutation accumulation, and multiple niche stem cells ensure that a lethal mutation within any single stem cell does not lead to crypt death. In addition, the architecture of the colon crypt stem cell niche may harness probability or chance to randomly discard many beneficial mutations that might lead to cancer. An analysis of somatic chromosome copy number alterations (CNAs reveals a lack of perfect fidelity in individual normal human crypts, with age-related increases and higher frequencies in ulcerative colitis, a proliferative, inflammatory disease. The age-related increase in somatic CNAs appears consistent with relatively normal replication error and cell division rates. Surprisingly, and similar to point mutations in cancer genomes, the types of crypt mutations were more consistent with random fixation rather than selection. In theory, a simple non-Darwinian way to nullify selection is to reduce the size of the reproducing population. Fates are more determined by chance rather than selection in very small populations, and therefore selection may be minimized within small crypt niches. The desired effect is that many beneficial mutations that might lead to cancer are randomly lost by drift rather than fixed by selection. The subdivision of the colon into multiple very small stem cell niches may trade Darwinian evolution for non-Darwinian somatic cell evolution, capitulating to aging but reducing cancer risks.

  16. Darwin and Reductionisms: Victorian, Neo-Darwinian and Postgenomic Biologies

    Directory of Open Access Journals (Sweden)

    Angelique Richardson

    2010-10-01

    Full Text Available This article compares the open-ended Darwinism of Charles Darwin, George Lewes, George Eliot and Thomas Hardy with reductive post-Weismann and early eugenist views and more recent neo-Darwinian ideas including literary Darwinism. It argues that some Victorians had a clear sense of the complexities of the natural world, and of the centrality of environment to life. This awareness contrasts with the processes of divorce and isolation that underpin neo-Darwinian understandings of evolutionary development. But biologists and philosophers of biology are now emphasising the complex and dynamic relations between organism and environment in ways that would have appealed to Darwin’s contemporaries. The article establishes that there are significant parallels between mid-Victorian and postgenomic thought.

  17. The Cellular Differential Evolution Based on Chaotic Local Search

    Directory of Open Access Journals (Sweden)

    Qingfeng Ding

    2015-01-01

    Full Text Available To avoid immature convergence and tune the selection pressure in the differential evolution (DE algorithm, a new differential evolution algorithm based on cellular automata and chaotic local search (CLS or ccDE is proposed. To balance the exploration and exploitation tradeoff of differential evolution, the interaction among individuals is limited in cellular neighbors instead of controlling parameters in the canonical DE. To improve the optimizing performance of DE, the CLS helps by exploring a large region to avoid immature convergence in the early evolutionary stage and exploiting a small region to refine the final solutions in the later evolutionary stage. What is more, to improve the convergence characteristics and maintain the population diversity, the binomial crossover operator in the canonical DE may be instead by the orthogonal crossover operator without crossover rate. The performance of ccDE is widely evaluated on a set of 14 bound constrained numerical optimization problems compared with the canonical DE and several DE variants. The simulation results show that ccDE has better performances in terms of convergence rate and solution accuracy than other optimizers.

  18. Emerging of Stochastic Dynamical Equalities and Steady State Thermodynamics from Darwinian Dynamics

    International Nuclear Information System (INIS)

    Ao, P.

    2008-01-01

    The evolutionary dynamics first conceived by Darwin and Wallace, referring to as Darwinian dynamics in the present paper, has been found to be universally valid in biology. The statistical mechanics and thermodynamics, while enormous successful in physics, have been in an awkward situation of wanting a consistent dynamical understanding. Here we present from a formal point of view an exploration of the connection between thermodynamics and Darwinian dynamics and a few related topics. We first show that the stochasticity in Darwinian dynamics implies the existence temperature, hence the canonical distribution of Boltzmann-Gibbs type. In term of relative entropy the Second Law of thermodynamics is dynamically demonstrated without detailed balance condition, and is valid regardless of size of the system. In particular, the dynamical component responsible for breaking detailed balance condition does not contribute to the change of the relative entropy. Two types of stochastic dynamical equalities of current interest are explicitly discussed in the present approach: One is based on Feynman-Kac formula and another is a generalization of Einstein relation. Both are directly accessible to experimental tests. Our demonstration indicates that Darwinian dynamics represents logically a simple and straightforward starting point for statistical mechanics and thermodynamics and is complementary to and consistent with conservative dynamics that dominates the physical sciences. Present exploration suggests the existence of a unified stochastic dynamical framework both near and far from equilibrium

  19. Indirect selection in Darwinian evolution : mechanisms and implications

    OpenAIRE

    Parsons, David

    2011-01-01

    The Aevol model is an in silico experimental evolution model that was specifically developped by Carole Knibbe to study the evolution of the structure of the genome. Using Aevol, a very strong second-order selective pressure towards a specific level of mutational variability of the phenotype was revealed: it was shown that since the survival of a lineage on the long term is conditionned to its ability to produce beneficial mutations while not loosing those previously found, a specific trade-o...

  20. The edge of neutral evolution in social dilemmas

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, Jonas; Frey, Erwin [Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universitaet Muenchen, Theresienstrasse 37, D-80333 Muenchen (Germany); Reichenbach, Tobias [Howard Hughes Medical Institute and Laboratory of Sensory Neuroscience, Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States)], E-mail: jonas.cremer@physik.uni-muenchen.de

    2009-09-15

    The functioning of animal as well as human societies fundamentally relies on cooperation. Yet, defection is often favorable for the selfish individual, and social dilemmas arise. Selection by individuals' fitness, usually the basic driving force of evolution, quickly eliminates cooperators. However, evolution is also governed by fluctuations that can be of greater importance than fitness differences, and can render evolution effectively neutral. Here, we investigate the effects of selection versus fluctuations in social dilemmas. By studying the mean extinction times of cooperators and defectors, a variable sensitive to fluctuations, we are able to identify and quantify an emerging 'edge of neutral evolution' that delineates regimes of neutral and Darwinian evolution. Our results reveal that cooperation is significantly maintained in the neutral regimes. In contrast, the classical predictions of evolutionary game theory, where defectors beat cooperators, are recovered in the Darwinian regimes. Our studies demonstrate that fluctuations can provide a surprisingly simple way to partly resolve social dilemmas. Our methods are generally applicable to estimate the role of random drift in evolutionary dynamics.

  1. The edge of neutral evolution in social dilemmas

    International Nuclear Information System (INIS)

    Cremer, Jonas; Frey, Erwin; Reichenbach, Tobias

    2009-01-01

    The functioning of animal as well as human societies fundamentally relies on cooperation. Yet, defection is often favorable for the selfish individual, and social dilemmas arise. Selection by individuals' fitness, usually the basic driving force of evolution, quickly eliminates cooperators. However, evolution is also governed by fluctuations that can be of greater importance than fitness differences, and can render evolution effectively neutral. Here, we investigate the effects of selection versus fluctuations in social dilemmas. By studying the mean extinction times of cooperators and defectors, a variable sensitive to fluctuations, we are able to identify and quantify an emerging 'edge of neutral evolution' that delineates regimes of neutral and Darwinian evolution. Our results reveal that cooperation is significantly maintained in the neutral regimes. In contrast, the classical predictions of evolutionary game theory, where defectors beat cooperators, are recovered in the Darwinian regimes. Our studies demonstrate that fluctuations can provide a surprisingly simple way to partly resolve social dilemmas. Our methods are generally applicable to estimate the role of random drift in evolutionary dynamics.

  2. Fractional order Darwinian particle swarm optimization applications and evaluation of an evolutionary algorithm

    CERN Document Server

    Couceiro, Micael

    2015-01-01

    This book examines the bottom-up applicability of swarm intelligence to solving multiple problems, such as curve fitting, image segmentation, and swarm robotics. It compares the capabilities of some of the better-known bio-inspired optimization approaches, especially Particle Swarm Optimization (PSO), Darwinian Particle Swarm Optimization (DPSO) and the recently proposed Fractional Order Darwinian Particle Swarm Optimization (FODPSO), and comprehensively discusses their advantages and disadvantages. Further, it demonstrates the superiority and key advantages of using the FODPSO algorithm, suc

  3. Conceptualizing the origin of life in terms of evolution

    NARCIS (Netherlands)

    Takeuchi, N; Hogeweg, P; Kaneko, K

    2017-01-01

    In this opinion piece, we discuss how to place evolution in the context of origin-of-life research. Our discussion starts with a popular definition: 'life is a self-sustained chemical system capable of undergoing Darwinian evolution'. According to this definition, the origin of life is the same as

  4. Teaching Evolution: A Heuristic Study of Personal and Cultural Dissonance

    Science.gov (United States)

    Grimes, Larry G.

    2012-01-01

    Darwinian evolution is a robustly supported scientific theory. Yet creationists continue to challenge its teaching in American public schools. Biology teachers in all 50 states are responsible for teaching science content standards that include evolution. As products of their backgrounds and affiliations teachers bring personal attitudes and…

  5. From Darwinian to technological evolution: forgetting the human lottery.

    Science.gov (United States)

    Tintino, Giorgio

    2014-01-01

    The GRIN technologies (-geno, -robo, -info, -nano) promise to change the inner constitution of human body and its own existence. This transformation involves the structure of our lives and represent a brave new world that we have to explore and to manage. In this sense, the traditional tools of humanism seems very inadequate to think the biotech century and there is a strong demand of a new thought for the evolution and the concrete history of life. The posthuman philosophy tries to take this new path of human existence in all of its novelty since GRIN technologies seem to promise new and unexpected paths of evolution to living beings and, above all, man. For this, the post-human thought, as we see, is a new anthropological overview on the concrete evolution of human being, an overview that involves an epistemological revolution of the categories that humanism uses to conceptualize the journey that divides the Homo sapiens from the man. But, is this right?

  6. Evolution of Positioning Techniques in Cellular Networks, from 2G to 4G

    Directory of Open Access Journals (Sweden)

    Rafael Saraiva Campos

    2017-01-01

    Full Text Available This review paper presents within a common framework the mobile station positioning methods applied in 2G, 3G, and 4G cellular networks, as well as the structure of the related 3GPP technical specifications. The evolution path through the generations is explored in three steps at each level: first, the new network elements supporting localization features are introduced; then, the standard localization methods are described; finally, the protocols providing specific support to mobile station positioning are studied. To allow a better understanding, this paper also brings a brief review of the cellular networks evolution paths.

  7. Evolution, religions and global Bioethics

    OpenAIRE

    Perbal, Laurence

    2007-01-01

    Creationist theories are still present in the United States and in Europe. The Darwinian theory of evolution is often considered as the starting point of important debates between religions and evolutionists. In this paper, we are principally interested in evolutionary creationism (or theistic evolutionism). The existence of a divine design in nature, the spiritual status of human beings and the emergence of human species as the purpose of evolution are some of those debates. The post-Darwini...

  8. Nothing in Evolution Makes Sense Except in the Light of Genomics: Read–Write Genome Evolution as an Active Biological Process

    Directory of Open Access Journals (Sweden)

    James A. Shapiro

    2016-06-01

    Full Text Available The 21st century genomics-based analysis of evolutionary variation reveals a number of novel features impossible to predict when Dobzhansky and other evolutionary biologists formulated the neo-Darwinian Modern Synthesis in the middle of the last century. These include three distinct realms of cell evolution; symbiogenetic fusions forming eukaryotic cells with multiple genome compartments; horizontal organelle, virus and DNA transfers; functional organization of proteins as systems of interacting domains subject to rapid evolution by exon shuffling and exonization; distributed genome networks integrated by mobile repetitive regulatory signals; and regulation of multicellular development by non-coding lncRNAs containing repetitive sequence components. Rather than single gene traits, all phenotypes involve coordinated activity by multiple interacting cell molecules. Genomes contain abundant and functional repetitive components in addition to the unique coding sequences envisaged in the early days of molecular biology. Combinatorial coding, plus the biochemical abilities cells possess to rearrange DNA molecules, constitute a powerful toolbox for adaptive genome rewriting. That is, cells possess “Read–Write Genomes” they alter by numerous biochemical processes capable of rapidly restructuring cellular DNA molecules. Rather than viewing genome evolution as a series of accidental modifications, we can now study it as a complex biological process of active self-modification.

  9. Physicochemical evolution and positive selection of the ...

    Indian Academy of Sciences (India)

    2010-04-08

    Apr 8, 2010 ... It is not clear whether matK evolves under Darwinian selection. In this study, the gymnosperm Taxaceae, Cephalotaxaceae and Pinaceae were used to illustrate the physicochemical evolution, molecular adaptation and evolutionary dynamics of gene divergence in matKs. matK sequences were amplified ...

  10. Selfish cellular networks and the evolution of complex organisms.

    Science.gov (United States)

    Kourilsky, Philippe

    2012-03-01

    Human gametogenesis takes years and involves many cellular divisions, particularly in males. Consequently, gametogenesis provides the opportunity to acquire multiple de novo mutations. A significant portion of these is likely to impact the cellular networks linking genes, proteins, RNA and metabolites, which constitute the functional units of cells. A wealth of literature shows that these individual cellular networks are complex, robust and evolvable. To some extent, they are able to monitor their own performance, and display sufficient autonomy to be termed "selfish". Their robustness is linked to quality control mechanisms which are embedded in and act upon the individual networks, thereby providing a basis for selection during gametogenesis. These selective processes are equally likely to affect cellular functions that are not gamete-specific, and the evolution of the most complex organisms, including man, is therefore likely to occur via two pathways: essential housekeeping functions would be regulated and evolve during gametogenesis within the parents before being transmitted to their progeny, while classical selection would operate on other traits of the organisms that shape their fitness with respect to the environment. Copyright © 2012 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  11. Research and Application on Fractional-Order Darwinian PSO Based Adaptive Extended Kalman Filtering Algorithm

    Directory of Open Access Journals (Sweden)

    Qiguang Zhu

    2014-05-01

    Full Text Available To resolve the difficulty in establishing accurate priori noise model for the extended Kalman filtering algorithm, propose the fractional-order Darwinian particle swarm optimization (PSO algorithm has been proposed and introduced into the fuzzy adaptive extended Kalman filtering algorithm. The natural selection method has been adopted to improve the standard particle swarm optimization algorithm, which enhanced the diversity of particles and avoided the premature. In addition, the fractional calculus has been used to improve the evolution speed of particles. The PSO algorithm after improved has been applied to train fuzzy adaptive extended Kalman filter and achieve the simultaneous localization and mapping. The simulation results have shown that compared with the geese particle swarm optimization training of fuzzy adaptive extended Kalman filter localization and mapping algorithm, has been greatly improved in terms of localization and mapping.

  12. On the Evolution of Human Language.

    Science.gov (United States)

    Lieberman, Philip

    Human linguistic ability depends, in part, on the gradual evolution of man's supralaryngeal vocal tract. The anatomic basis of human speech production is the result of a long evolutionary process in which the Darwinian process of natural selection acted to retain mutations. For auditory perception, the listener operates in terms of the acoustic…

  13. Darwinian Model Building

    International Nuclear Information System (INIS)

    Kester, Do; Bontekoe, Romke

    2011-01-01

    We present a way to generate heuristic mathematical models based on the Darwinian principles of variation and selection in a pool of individuals over many generations. Each individual has a genotype (the hereditary properties) and a phenotype (the expression of these properties in the environment). Variation is achieved by cross-over and mutation operations on the genotype which consists in the present case of a single chromosome. The genotypes 'live' in the environment of the data. Nested Sampling is used to optimize the free parameters of the models given the data, thus giving rise to the phenotypes. Selection is based on the phenotypes.The evidences which naturally follow from the Nested Sampling Algorithm are used in a second level of Nested Sampling to find increasingly better models.The data in this paper originate from the Leiden Cytology and Pathology Laboratory (LCPL), which screens pap smears for cervical cancer. We have data for 1750 women who on average underwent 5 tests each. The data on individual women are treated as a small time series. We will try to estimate the next value of the prime cancer indicator from previous tests of the same woman.

  14. Darwinian Evolution of Mutualistic RNA Replicators with Different Genes

    Science.gov (United States)

    Mizuuchi, R.; Ichihashi, N.

    2017-07-01

    We report a sustainable long-term replication and evolution of two distinct cooperative RNA replicators encoding different genes. One of the RNAs evolved to maintain or increase the cooperativity, despite selective advantage of selfish mutations.

  15. Evolutionism through Chinese Eyes: Yan Fu, Ma Junwu and Their translations of Darwinian Evolutionism

    Directory of Open Access Journals (Sweden)

    Tsing-song Vincent Shen

    2015-04-01

    Full Text Available The huge impact that Darwinian Evolutionism has effected over Chinese intellectuals through Yan Fu's translation of Huxley's "Evolution and Ethics" into the Tianyanlun, is in fact based on Chinese traditional worldview on the one hand and the novel ideas it brings to the Chinese mind facing the challenge of transition. However, Yan Fu's translation is not as scientific as it should be when dealing with Huxley's discourse. Ma Junwu's translation of Darwin's "On the Origin of Species" attempts to be more scientific, in an effort to supply exact scientific terms and discourse in Chinese. However, at the end it is social Darwinism that has won the mind of the Chinese people. This paper analyses the ideas in Chinese past that leads to Chinese perception of Darwimism evolutionism and examines the ways it has been translated by Yan Fu and Ma Junwu.  

  16. Application of a cellular automaton for the evolution of etched nuclear tracks

    International Nuclear Information System (INIS)

    Cruz-Trujillo, Leonardo de la; Hernández-Hernández, C.; Vázquez-López, C.; Zendejas-Leal, B.E.; Golzarri, I.; Espinosa, G.

    2013-01-01

    In the present work, it is demonstrated the first application of cellular automata to the growing of etched nuclear tracks. The simplest case in which conical etched tracks are gradually formed is presented, as well as a general case of time varying etching rate V t . It is demonstrated that the cellular automata elements consist in an image pattern of the latent nuclear track input cells, 16 rules for updating states, the Moore neighborhood and an algorithm of four states. - Highlights: ► We model the evolution of an etched nuclear track using cellular automata (ca). ► A cellular automaton of a conical track has 4 states and 16 transition rules. ► The ca of general tracks require a not regular mesh and the L(t) and V b parameters

  17. Breeding novel solutions in the brain: a model of Darwinian neurodynamics.

    Science.gov (United States)

    Szilágyi, András; Zachar, István; Fedor, Anna; de Vladar, Harold P; Szathmáry, Eörs

    2016-01-01

    Background : The fact that surplus connections and neurons are pruned during development is well established. We complement this selectionist picture by a proof-of-principle model of evolutionary search in the brain, that accounts for new variations in theory space. We present a model for Darwinian evolutionary search for candidate solutions in the brain. Methods : We combine known components of the brain - recurrent neural networks (acting as attractors), the action selection loop and implicit working memory - to provide the appropriate Darwinian architecture. We employ a population of attractor networks with palimpsest memory. The action selection loop is employed with winners-share-all dynamics to select for candidate solutions that are transiently stored in implicit working memory. Results : We document two processes: selection of stored solutions and evolutionary search for novel solutions. During the replication of candidate solutions attractor networks occasionally produce recombinant patterns, increasing variation on which selection can act. Combinatorial search acts on multiplying units (activity patterns) with hereditary variation and novel variants appear due to (i) noisy recall of patterns from the attractor networks, (ii) noise during transmission of candidate solutions as messages between networks, and, (iii) spontaneously generated, untrained patterns in spurious attractors. Conclusions : Attractor dynamics of recurrent neural networks can be used to model Darwinian search. The proposed architecture can be used for fast search among stored solutions (by selection) and for evolutionary search when novel candidate solutions are generated in successive iterations. Since all the suggested components are present in advanced nervous systems, we hypothesize that the brain could implement a truly evolutionary combinatorial search system, capable of generating novel variants.

  18. Darwinism and the Behavioral Theory of Sociocultural Evolution: An Analysis.

    Science.gov (United States)

    Langdon, John

    1979-01-01

    Challenges the view that the social sciences are theoretically impoverished disciplines when compared with the natural sciences. Demonstrates that the synthesis of an abstract Darwinian model of systemic adaptation and the behavioral principles of social learning produces a logical theory of sociocultural evolution. (DB)

  19. Evolution of probability measures by cellular automata on algebraic topological Markov chains

    Directory of Open Access Journals (Sweden)

    ALEJANDRO MAASS

    2003-01-01

    Full Text Available In this paper we review some recent results on the evolution of probability measures under cellular automata acting on a fullshift. In particular we discuss the crucial role of the attractiveness of maximal measures. We enlarge the context of the results of a previous study of topological Markov chains that are Abelian groups; the shift map is an automorphism of this group. This is carried out by studying the dynamics of Markov measures by a particular additive cellular automata. Many of these topics were within the focus of Francisco Varela's mathematical interests.

  20. Evolution by epigenesis: farewell to Darwinism, neo- and otherwise.

    Science.gov (United States)

    Balon, Eugene K

    2004-01-01

    In the last 25 years, criticism of most theories advanced by Darwin and the neo-Darwinians has increased considerably, and so did their defense. Darwinism has become an ideology, while the most significant theories of Darwin were proven unsupportable. The critics advanced other theories instead of 'natural selection' and the survival of the fittest'. 'Saltatory ontogeny' and 'epigenesis' are such new theories proposed to explain how variations in ontogeny and novelties in evolution are created. They are reviewed again in the present essay that also tries to explain how Darwinians, artificially kept dominant in academia and in granting agencies, are preventing their acceptance. Epigenesis, the mechanism of ontogenies, creates in every generation alternative variations in a saltatory way that enable the organisms to survive in the changing environments as either altricial or precocial forms. The constant production of two such forms and their survival in different environments makes it possible, over a sequence of generations, to introduce changes and establish novelties--the true phenomena of evolution. The saltatory units of evolution remain far-from-stable structures capable of self-organization and self-maintenance (autopoiesis).

  1. Evolution of the cellular communication system: An analysis in the Computational Paradigm

    International Nuclear Information System (INIS)

    Tahir Shah, K.

    1995-03-01

    We discuss the problem of the evolution of the cellular communication system from the RNA world to progenote to the modern cell. Our method analyses syntactical structure of molecular fossils in the non-coding regions of DNA within the information-processing gene model developed earlier. We concluded that sequence-specific binding is an ancient communication process with its origin in the RNA world. Moreover, we illustrate our viewpoint using four evolution snapshots from the first RNA segments, some 4.1. billion years ago, to the first cell, 3.8 billion years ago. (author). 31 refs

  2. DARWIN Y LOS DILEMAS SOCIALES

    Directory of Open Access Journals (Sweden)

    Alejandro Rosas

    2009-10-01

      I describe the project of a Darwinian explanation of morality following Darwin’s basic ideas as expressed in The Descent of Man. In contrast to the traditional interpretation, I argue that Darwin did not assume, nor is it necessary to assume in a Darwinian perspective, an inevitable conflict between individual and group selection in the explanation of morality. Both operate in synergy to favor traits that support moral behavior. I also argue that two teachings result from this Darwinian project, one for moral philosophy and the other for the theory of natural selection. The first puts social dilemmas in the heart of human morality; the second puts cooperation in the core of natural selection. I illustrate the second point with recent research into the evolution of multi-cellular organisms.

  3. Brassinosteroid action in flowering plants: a Darwinian perspective.

    Science.gov (United States)

    Kutschera, Ulrich; Wang, Zhi-Yong

    2012-06-01

    The year 2012 marks the 150th anniversary of the publication of Charles Darwin's first botanical book, on the fertilization of orchids (1862), wherein he described pollen grains and outlined his evolutionary principles with respect to plant research. Five decades later, the growth-promoting effect of extracts of Orchid pollen on coleoptile elongation was documented. These studies led to the discovery of a new class of phytohormones, the brassinosteroids (BRs) that were isolated from rapeseed (Brassica napus) pollen. These growth-promoting steroids, which regulate height, fertility, and seed-filling in crop plants such as rice (Oryza sativa), also induce stress- and disease resistance in green algae and angiosperms. The origin and current status of BR-research is described here, with reference to BR-action and -signal transduction, and it is shown that modern high-yield rice varieties with erect leaves are deficient in endogenous BRs. Since brassinosteroids induce pathogen resistance in rice plants and hence can suppress rice blast- and bacterial blight-diseases, genetic manipulation of BR-biosynthesis or -perception may be a means to increase crop production. Basic research on BR activity in plants, such as Arabidopsis and rice, has the potential to increase crop yields further as part of a 21th century 'green biotech-revolution' that can be traced back to Darwin's classical breeding experiments. It is concluded that 'Nothing in brassinosteroid research makes sense except in the light of Darwinian evolution' and the value of basic science is highlighted, with reference to the genetic engineering of better food crops that may become resistant to a variety of plant diseases.

  4. The molecular and mathematical basis of Waddington's epigenetic landscape: a framework for post-Darwinian biology?

    Science.gov (United States)

    Huang, Sui

    2012-02-01

    The Neo-Darwinian concept of natural selection is plausible when one assumes a straightforward causation of phenotype by genotype. However, such simple 1:1 mapping must now give place to the modern concepts of gene regulatory networks and gene expression noise. Both can, in the absence of genetic mutations, jointly generate a diversity of inheritable randomly occupied phenotypic states that could also serve as a substrate for natural selection. This form of epigenetic dynamics challenges Neo-Darwinism. It needs to incorporate the non-linear, stochastic dynamics of gene networks. A first step is to consider the mathematical correspondence between gene regulatory networks and Waddington's metaphoric 'epigenetic landscape', which actually represents the quasi-potential function of global network dynamics. It explains the coexistence of multiple stable phenotypes within one genotype. The landscape's topography with its attractors is shaped by evolution through mutational re-wiring of regulatory interactions - offering a link between genetic mutation and sudden, broad evolutionary changes. Copyright © 2012 WILEY Periodicals, Inc.

  5. Physical microscopic free-choice model in the framework of a Darwinian approach to quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Baladron, Carlos [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, E-47011, Valladolid (Spain)

    2017-06-15

    A compatibilistic model of free choice for a fundamental particle is built within a general framework that explores the possibility that quantum mechanics be the emergent result of generalised Darwinian evolution acting on the abstract landscape of possible physical theories. The central element in this approach is a probabilistic classical Turing machine -basically an information processor plus a randomiser- methodologically associated with every fundamental particle. In this scheme every system acts not under a general law, but as a consequence of the command of a particular, evolved algorithm. This evolved programme enables the particle to algorithmically anticipate possible future world configurations in information space, and as a consequence, without altering the natural forward causal order in physical space, to incorporate elements to the decision making procedure that are neither purely random nor strictly in the past, but in a possible future. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Mass extinctions vs. uniformitarianism in biological evolution

    Energy Technology Data Exchange (ETDEWEB)

    Bak, P.; Paczuski, M.

    1995-12-31

    It is usually believed that Darwin`s theory leads to a smooth gradual evolution, so that mass extinctions must be caused by external shocks. However, it has recently been argued that mass extinctions arise from the intrinsic dynamics of Darwinian evolution. Species become extinct when swept by intermittent avalanches propagating through the global ecology. These ideas are made concrete through studies of simple mathematical models of co-evolving species. The models exhibit self-organized criticality and describe some general features of the extinction pattern in the fossil record.

  7. Aesthetic evolution by mate choice: Darwin's really dangerous idea.

    Science.gov (United States)

    Prum, Richard O

    2012-08-19

    Darwin proposed an explicitly aesthetic theory of sexual selection in which he described mate preferences as a 'taste for the beautiful', an 'aesthetic capacity', etc. These statements were not merely colourful Victorian mannerisms, but explicit expressions of Darwin's hypothesis that mate preferences can evolve for arbitrarily attractive traits that do not provide any additional benefits to mate choice. In his critique of Darwin, A. R. Wallace proposed an entirely modern mechanism of mate preference evolution through the correlation of display traits with male vigour or viability, but he called this mechanism natural selection. Wallace's honest advertisement proposal was stridently anti-Darwinian and anti-aesthetic. Most modern sexual selection research relies on essentially the same Neo-Wallacean theory renamed as sexual selection. I define the process of aesthetic evolution as the evolution of a communication signal through sensory/cognitive evaluation, which is most elaborated through coevolution of the signal and its evaluation. Sensory evaluation includes the possibility that display traits do not encode information that is being assessed, but are merely preferred. A genuinely Darwinian, aesthetic theory of sexual selection requires the incorporation of the Lande-Kirkpatrick null model into sexual selection research, but also encompasses the possibility of sensory bias, good genes and direct benefits mechanisms.

  8. Five Misunderstandings About Cultural Evolution.

    Science.gov (United States)

    Henrich, Joseph; Boyd, Robert; Richerson, Peter J

    2008-06-01

    Recent debates about memetics have revealed some widespread misunderstandings about Darwinian approaches to cultural evolution. Drawing from these debates, this paper disputes five common claims: (1) mental representations are rarely discrete, and therefore models that assume discrete, gene-like particles (i.e., replicators) are useless; (2) replicators are necessary for cumulative, adaptive evolution; (3) content-dependent psychological biases are the only important processes that affect the spread of cultural representations; (4) the "cultural fitness" of a mental representation can be inferred from its successful transmission; and (5) selective forces only matter if the sources of variation are random. We close by sketching the outlines of a unified evolutionary science of culture.

  9. Iconoclasts of Evolution: Haeckel, Behe, Wells & the Ontogeny of a Fraud

    Science.gov (United States)

    Pickett, Kurt M.; Wenzel, John W.; Rissing, Steven W.

    2005-01-01

    Behe (1998) and Wells (1999) claimed that embryological support for Darwinian evolution is based on the drawings of the 19th century embryologist Ernst Haeckel (1834-1919) whose embryological drawings were regarded inaccurate and fraudulent. The history of modern embryology, the roles played by Von Baer and Haeckel in that history and the manner…

  10. Boltzmann, Einstein, Natural Law and Evolution

    International Nuclear Information System (INIS)

    Broda, E.

    1980-01-01

    Like Boltzmann, Einstein was a protagonist of atomistics. As a physicist, he has been called Boltzmann's true successor. Also in epistemology, after overcoming the positivist influence of Mach, Einstein approached Boltzmann. Any difference between Boltzmann's realism, or even materialism, and Einstein's pantheism may be merely a matter of emphasis. Yet a real difference exists in another respect. Boltzmann explained man's power of thinking and feeling, his morality and his esthetic sense, on an evolutionary, Darwinian, basis. In contrast, evolution had no role in Einstein's thought, though Darwin was accepted by him. This lack of appreciation of the importance of evolution is now attributed to socio-political factors. (author)

  11. Testing gradual and speciational models of evolution in extant taxa: the example of ratites

    NARCIS (Netherlands)

    Laurin, M.; Gussekloo, S.W.S.; Marjanovic, D.; Legendre, L.; Cubo, J.

    2012-01-01

    Ever since Eldredge and Gould proposed their model of punctuated equilibria, evolutionary biologists have debated how often this model is the best description of nature and how important it is compared to the more gradual models of evolution expected from natural selection and the neo-Darwinian

  12. Why mental disorders are just mental dysfunctions (and nothing more): some Darwinian arguments.

    Science.gov (United States)

    De Block, Andreas

    2008-09-01

    Mental disorders are often thought to be harmful dysfunctions. Jerome Wakefield has argued that such dysfunctions should be understood as failures of naturally selected functions. This suggests, implicitly, that evolutionary biology and other Darwinian disciplines hold important information for anyone working on answering the philosophical question, 'what is a mental disorder?'. In this article, the author argues that Darwinian theory is not only relevant to the understanding of the disrupted functions, but it also sheds light on the disruption itself, as well as on the harm that attends the disruption. The arguments advanced here are partially based on the view that a core feature of Darwinism is that it stresses the environmental relativity of functions and dysfunctions. These arguments show a very close empirical connection between social judgments (values) and dysfunctions (psychopathology), which is of interest for psychiatric theory. Philosophically, they lead to the conclusion that the concept of mental disorder is identical to the concept of mental dysfunction. Consequently, it is both misleading and redundant to conceptualize mental disorders as 'harmful dysfunctions', and not simply as 'mental dysfunctions'.

  13. Exaptation in human evolution: how to test adaptive vs exaptive evolutionary hypotheses.

    Science.gov (United States)

    Pievani, Telmo; Serrelli, Emanuele

    2011-01-01

    Palaeontologists, Stephen J. Gould and Elisabeth Vrba, introduced the term "ex-aptation" with the aim of improving and enlarging the scientific language available to researchers studying the evolution of any useful character, instead of calling it an "adaptation" by default, coming up with what Gould named an "extended taxonomy of fitness". With the extension to functional co-optations from non-adaptive structures ("spandrels"), the notion of exaptation expanded and revised the neo-Darwinian concept of "pre-adaptation" (which was misleading, for Gould and Vrba, suggesting foreordination). Exaptation is neither a "saltationist" nor an "anti-Darwinian" concept and, since 1982, has been adopted by many researchers in evolutionary and molecular biology, and particularly in human evolution. Exaptation has also been contested. Objections include the "non-operationality objection".We analyze the possible operationalization of this concept in two recent studies, and identify six directions of empirical research, which are necessary to test "adaptive vs. exaptive" evolutionary hypotheses. We then comment on a comprehensive survey of literature (available online), and on the basis of this we make a quantitative and qualitative evaluation of the adoption of the term among scientists who study human evolution. We discuss the epistemic conditions that may have influenced the adoption and appropriate use of exaptation, and comment on the benefits of an "extended taxonomy of fitness" in present and future studies concerning human evolution.

  14. The population dynamics of cancer: a Darwinian perspective.

    Science.gov (United States)

    Vineis, Paolo; Berwick, Marianne

    2006-10-01

    Carcinogenesis, at least for some types of cancer, can be interpreted as the consequence of selection of mutated cells similar to what, in the theory of evolution, occurs at the population level. Instead of considering a population of organisms, we can refer to a population of cells belonging to multicellular organisms. Many carcinogens are mutagens, and the observed geographic distribution of cancer is, at least in part, attributable to environmental mutagens. However, the rapid change in risk for some cancers after migration suggests that carcinogenesis involves--in addition to mutations--some late event that most probably consists of the selection of cells already carrying mutations. We review a few examples of such selective pressures: finasteride in prostate cancer, vitamin supplementation in smokers, acquired resistance to chemotherapy, peripheral resistance to insulin, and sunlight and mutations in melanoma. A disease model for such a hypothesis is represented by Paroxysmal Nocturnal Hemoglobinuria (PNH). Mutations can be present at birth, as in the case of PNH, and can have a frequency much higher than the occurrence of the corresponding disease (PNH or lymphocytic leukaemia in children). However, PNH does not require a mutator phenotype, only a mutant phenotype followed by selection. A characteristic feature of cancer, instead, is likely to be the development of the mutator phenotype. We propose a 'Darwinian' model of carcinogenesis. If the model is correct, it suggests that prevention is more complex than avoiding exposure to mutagens. Mutations and genetic instability can be already present at birth. Mutations can be selected in the course of life if they increase survival advantage of the cell under certain environmental circumstances. In addition, gene-environment interactions cannot be interpreted according to a simplified linear model (based on the 'analysis of variance' concept); experimental work suggests that a more comprehensive non

  15. César Vallejo and the Stones of Darwinian Risk

    Directory of Open Access Journals (Sweden)

    Christiane von Buelow

    1990-01-01

    Full Text Available César Vallejo's short story, "Los caynas" (1923, relates a tale of species mutation, of men who become apes. The story, however, is something more than the reflection of the positivist interpretation of Darwinian theory. It can be read as a critique of Positivism's pseudo-scientific ideals or as a version of the Oedipal drama in which the son encounters and rejects his ape father. The ambivalence raises the question of whether Vallejo's Darwinism is to be read literally or ironically as well, as marking an antinomy present throughout his writing between the human subject's immersion in the species and the possibility of a collective human-transformation.

  16. Getting to Darwin: Obstacles to Accepting Evolution by Natural Selection

    Science.gov (United States)

    Thagard, Paul; Findlay, Scott

    2010-06-01

    Darwin’s theory of evolution by natural selection is central to modern biology, but is resisted by many people. This paper discusses the major psychological obstacles to accepting Darwin’s theory. Cognitive obstacles to adopting evolution by natural selection include conceptual difficulties, methodological issues, and coherence problems that derive from the intuitiveness of alternative theories. The main emotional obstacles to accepting evolution are its apparent conflict with valued beliefs about God, souls, and morality. We draw on the philosophy of science and on a psychological theory of cognitive and emotional belief revision to make suggestions about what can be done to improve acceptance of Darwinian ideas.

  17. Evolution of Cellular Automata toward a LIFE-Like Rule Guided by 1/ƒ Noise

    Science.gov (United States)

    Ninagawa, Shigeru

    There is evidence in favor of a relationship between the presence of 1/ƒ noise and computational universality in cellular automata. To confirm the relationship, we search for two-dimensional cellular automata with a 1/ƒ power spectrum by means of genetic algorithms. The power spectrum is calculated from the evolution of the state of the cell, starting from a random initial configuration. The fitness is estimated by the power spectrum with consideration of the spectral similarity to the 1/ƒ spectrum. The result shows that the rule with the highest fitness over the most runs exhibits a 1/ƒ type spectrum and its transition function and behavior are quite similar to those of the Game of Life, which is known to be a computationally universal cellular automaton. These results support the relationship between the presence of 1/ƒ noise and computational universality.

  18. Opinion evolution based on cellular automata rules in small world networks

    Science.gov (United States)

    Shi, Xiao-Ming; Shi, Lun; Zhang, Jie-Fang

    2010-03-01

    In this paper, we apply cellular automata rules, which can be given by a truth table, to human memory. We design each memory as a tracking survey mode that keeps the most recent three opinions. Each cellular automata rule, as a personal mechanism, gives the final ruling in one time period based on the data stored in one's memory. The key focus of the paper is to research the evolution of people's attitudes to the same question. Based on a great deal of empirical observations from computer simulations, all the rules can be classified into 20 groups. We highlight the fact that the phenomenon shown by some rules belonging to the same group will be altered within several steps by other rules in different groups. It is truly amazing that, compared with the last hundreds of presidential voting in America, the eras of important events in America's history coincide with the simulation results obtained by our model.

  19. Evolution of experimental deciduomata in the rat: cellular filiation and morphogenesis

    International Nuclear Information System (INIS)

    Dupont, Henri; Sartor, Pierre; Dupont, M.-A.; Duluc, A.-J.; Mayer, Gaston

    1978-01-01

    The morphogenesis of experimental deciduomata and the genesis of polyploidy in this tissue were studied by radioautographic and ultrastructural techniques in the rat. The growth is effected by mitotic renewal of diploid cells which are in post-synthetic resting period. They themselves organize by forming cellular strings. The level of Polyploidy is determined by the modality of division. Mitotic divisions without cytodieresis lead to a substantial pool of binucleated cells (2n + 2n) in mesometrial and antimesometrial areas. Mitotic divisions for binucleated cells with a single spindle can create tetraploid mononucleated cells. This mitotic type of division limits the polyploidy to 4 n in mesometrial cells. In antimesometrial area the evolution continues above 4 n nuclei by means of endomitosis, without any filiation between mono-and binucleated cells. In some respects, this evolution agrees with results obtained in hepatic tissue in the rat [fr

  20. Synthetic genetic polymers capable of heredity and evolution

    DEFF Research Database (Denmark)

    Pinheiro, Vitor B; Taylor, Alexander I; Cozens, Christopher

    2012-01-01

    in and recovered from six alternative genetic polymers based on simple nucleic acid architectures not found in nature [xeno-nucleic acids (XNAs)]. We also select XNA aptamers, which bind their targets with high affinity and specificity, demonstrating that beyond heredity, specific XNAs have the capacity......Genetic information storage and processing rely on just two polymers, DNA and RNA, yet whether their role reflects evolutionary history or fundamental functional constraints is currently unknown. With the use of polymerase evolution and design, we show that genetic information can be stored...... for Darwinian evolution and folding into defined structures. Thus, heredity and evolution, two hallmarks of life, are not limited to DNA and RNA but are likely to be emergent properties of polymers capable of information storage....

  1. Unfinished stories on viral quasispecies and Darwinian views of evolution.

    Science.gov (United States)

    Más, Antonio; López-Galíndez, Cecilio; Cacho, Isabel; Gómez, Jordi; Martínez, Miguel Angel

    2010-04-09

    Experimental evidence that RNA virus populations consist of distributions of mutant genomes, termed quasispecies, was first published 31 years ago. This work provided the earliest experimental support for a theory to explain a system that replicated with limited fidelity and to understand the self-organization and adaptability of early life forms on Earth. High mutation rates and quasispecies dynamics of RNA viruses are intimately related to both viral disease and antiviral treatment strategies. Moreover, the quasispecies concept is being applied to other biological systems such as cancer research in which cellular mutant spectra can be also detected. This review addresses some of the unanswered questions regarding viral and theoretical quasispecies concepts as well as more practical aspects concerning resistance to antiviral treatments and pathogenesis. (c) 2010 Elsevier Ltd. All rights reserved.

  2. What Does "the RNA World" Mean to "the Origin of Life"?

    Science.gov (United States)

    Ma, Wentao

    2017-11-29

    Corresponding to life's two distinct aspects: Darwinian evolution and self-sustainment, the origin of life should also split into two issues: the origin of Darwinian evolution and the arising of self-sustainment. Because the "self-sustainment" we concern about life should be the self-sustainment of a relevant system that is "defined" by its genetic information, the self-sustainment could not have arisen before the origin of Darwinian evolution, which was just marked by the emergence of genetic information. The logic behind the idea of the RNA world is not as tenable as it has been believed. That is, genetic molecules and functional molecules, even though not being the same material, could have emerged together in the beginning and launched the evolution-provided that the genetic molecules can "simply" code the functional molecules. However, due to these or those reasons, alternative scenarios are generally much less convincing than the RNA world. In particular, when considering the accumulating experimental evidence that is supporting a de novo origin of the RNA world, it seems now quite reasonable to believe that such a world may have just stood at the very beginning of life on the Earth. Therewith, we acquire a concrete scenario for our attempts to appreciate those fundamental issues that are involved in the origin of life. In the light of those possible scenes included in this scenario, Darwinian evolution may have originated at the molecular level, realized upon a functional RNA. When two or more functional RNAs emerged, for their efficient cooperation, there should have been a selective pressure for the emergence of protocells. But it was not until the appearance of the "unitary-protocell", which had all of its RNA genes linked into a chromosome, that Darwinian evolution made its full step towards the cellular level-no longer severely constrained by the low-grade evolution at the molecular level. Self-sustainment did not make sense before protocells emerged

  3. Cellular Particle Dynamics simulation of biomechanical relaxation processes of multi-cellular systems

    Science.gov (United States)

    McCune, Matthew; Kosztin, Ioan

    2013-03-01

    Cellular Particle Dynamics (CPD) is a theoretical-computational-experimental framework for describing and predicting the time evolution of biomechanical relaxation processes of multi-cellular systems, such as fusion, sorting and compression. In CPD, cells are modeled as an ensemble of cellular particles (CPs) that interact via short range contact interactions, characterized by an attractive (adhesive interaction) and a repulsive (excluded volume interaction) component. The time evolution of the spatial conformation of the multicellular system is determined by following the trajectories of all CPs through numerical integration of their equations of motion. Here we present CPD simulation results for the fusion of both spherical and cylindrical multi-cellular aggregates. First, we calibrate the relevant CPD model parameters for a given cell type by comparing the CPD simulation results for the fusion of two spherical aggregates to the corresponding experimental results. Next, CPD simulations are used to predict the time evolution of the fusion of cylindrical aggregates. The latter is relevant for the formation of tubular multi-cellular structures (i.e., primitive blood vessels) created by the novel bioprinting technology. Work supported by NSF [PHY-0957914]. Computer time provided by the University of Missouri Bioinformatics Consortium.

  4. Nothing in the History of Spanish "Anis" Makes Sense, Except in the Light of Evolution

    Science.gov (United States)

    Delgado, Juan Antonio; Palma, Ricardo Luis

    2011-01-01

    We describe, discuss and illustrate a metaphoric parallel between the history of the most famous Spanish liqueur, "Anis del Mono" ("Anis" of the Monkey), and the evolution of living organisms in the light of Darwinian theory and other biological hypotheses published subsequent to Charles Darwin's "Origin of Species." Also, we report the use of a…

  5. Global Rebalancing of Cellular Resources by Pleiotropic Point Mutations Illustrates a Multi-scale Mechanism of Adaptive Evolution

    DEFF Research Database (Denmark)

    Utrilla, José; O'Brien, Edward J.; Chen, Ke

    2016-01-01

    Pleiotropic regulatory mutations affect diverse cellular processes, posing a challenge to our understanding of genotype-phenotype relationships across multiple biological scales. Adaptive laboratory evolution (ALE) allows for such mutations to be found and characterized in the context of clear se...

  6. Field Studies: Novels as Darwinian Niches, Poetry for Physicists and Mathematicians

    Directory of Open Access Journals (Sweden)

    Daniel Walter Brown

    2010-10-01

    Full Text Available This brief forum contribution reflects upon some historical factors in the formation of nineteenth century science and of the literature and science discipline that has since arisen to study its literary receptions. Noting the preponderance of studies focusing upon forms of scientific developmentalism, principally Darwinian biology, and of novels and other prose, and more broadly, on literary figures, rather than the writings of scientists, the paper introduces some poetry on science by scientists. It concentrates principally on those working and writing in the fields of physics and mathematics, areas that have been neglected in literature and science studies.

  7. Cellular protein quality control and the evolution of aggregates in spinocerebellar ataxia type 3 (SCA3)

    NARCIS (Netherlands)

    Seidel, K.; Meister, M.; Dugbartey, G. J.; Zijlstra, M. P.; Vinet, J.; Brunt, E. R. P.; van Leeuwen, F. W.; Rueb, U.; Kampinga, H. H.; den Dunnen, W. F. A.

    2012-01-01

    K. Seidel, M. Meister, G. J. Dugbartey, M. P. Zijlstra, J. Vinet, E. R. P. Brunt, F. W. van Leeuwen, U. Rub, H. H. Kampinga and W. F. A. den Dunnen (2012) Neuropathology and Applied Neurobiology38, 548558 Cellular protein quality control and the evolution of aggregates in spinocerebellar ataxia type

  8. The Darwinian revolution La revolución darwiniana

    Directory of Open Access Journals (Sweden)

    ÓSCAR M CHAVES

    2010-06-01

    Full Text Available The scientific revolution probably began at 16th century with the heliocentric theory of the eminent astronomer Nicolaus Copernicus, but it was culminated with the masterful discoveries of Galileo Galilei and Isaac Newton at 17th century who revealed that planet movements around the sun and other similar phenomena can be explained by simple mechanical laws of physics and astronomy. However, the origin, complexity and configuration of living beings remained in the mystery until 19th century, with the publication of "On the origin of species". In this essay I discuss the importance of the Darwinian scientific revolution, its beginnings, and the main objections of creationists to his evolutionary ideas. Darwin demonstrated that the origin and complexity of living beings can be explained by natural processes, without the intervention of a supernatural being. However, the beginnings of the Darwinian revolution were particularly difficult and 128 years after his death, the controversy between evolutionists and creationists still persists.Con base en la teoría heliocéntrica formulada por Nicolás Copérnico en el siglo XVI, Galileo Galilei e Isaac Newton iniciaron la revolución científica al demostrar que los movimientos de los planetas alrededor del sol podían ser explicados por las leyes de la física y la astronomía. No obstante, el origen y complejidad del mundo orgánico permaneció en el misterio hasta mediados del siglo XIX, cuando Charles Darwin publicó su célebre obra 'El origen de las especies'. Desde entonces, la selección natural se ha convertido en una de las teorías científicas más umversalmente aceptadas y Darwin en el fundador de la biología moderna. En este ensayo se discute la importancia de la revolución darwiniana, sus inicios y las principales objeciones de sus detractores. Darwin demostró que el origen y la complejidad de los seres vivos pueden ser explicados por procesos naturales sin necesidad de la intervenci

  9. What Does “the RNA World” Mean to “the Origin of Life”?

    Directory of Open Access Journals (Sweden)

    Wentao Ma

    2017-11-01

    Full Text Available Corresponding to life’s two distinct aspects: Darwinian evolution and self-sustainment, the origin of life should also split into two issues: the origin of Darwinian evolution and the arising of self-sustainment. Because the “self-sustainment” we concern about life should be the self-sustainment of a relevant system that is “defined” by its genetic information, the self-sustainment could not have arisen before the origin of Darwinian evolution, which was just marked by the emergence of genetic information. The logic behind the idea of the RNA world is not as tenable as it has been believed. That is, genetic molecules and functional molecules, even though not being the same material, could have emerged together in the beginning and launched the evolution—provided that the genetic molecules can “simply” code the functional molecules. However, due to these or those reasons, alternative scenarios are generally much less convincing than the RNA world. In particular, when considering the accumulating experimental evidence that is supporting a de novo origin of the RNA world, it seems now quite reasonable to believe that such a world may have just stood at the very beginning of life on the Earth. Therewith, we acquire a concrete scenario for our attempts to appreciate those fundamental issues that are involved in the origin of life. In the light of those possible scenes included in this scenario, Darwinian evolution may have originated at the molecular level, realized upon a functional RNA. When two or more functional RNAs emerged, for their efficient cooperation, there should have been a selective pressure for the emergence of protocells. But it was not until the appearance of the “unitary-protocell”, which had all of its RNA genes linked into a chromosome, that Darwinian evolution made its full step towards the cellular level—no longer severely constrained by the low-grade evolution at the molecular level. Self-sustainment did

  10. Evolution and mass extinctions as lognormal stochastic processes

    Science.gov (United States)

    Maccone, Claudio

    2014-10-01

    In a series of recent papers and in a book, this author put forward a mathematical model capable of embracing the search for extra-terrestrial intelligence (SETI), Darwinian Evolution and Human History into a single, unified statistical picture, concisely called Evo-SETI. The relevant mathematical tools are: (1) Geometric Brownian motion (GBM), the stochastic process representing evolution as the stochastic increase of the number of species living on Earth over the last 3.5 billion years. This GBM is well known in the mathematics of finances (Black-Sholes models). Its main features are that its probability density function (pdf) is a lognormal pdf, and its mean value is either an increasing or, more rarely, decreasing exponential function of the time. (2) The probability distributions known as b-lognormals, i.e. lognormals starting at a certain positive instant b>0 rather than at the origin. These b-lognormals were then forced by us to have their peak value located on the exponential mean-value curve of the GBM (Peak-Locus theorem). In the framework of Darwinian Evolution, the resulting mathematical construction was shown to be what evolutionary biologists call Cladistics. (3) The (Shannon) entropy of such b-lognormals is then seen to represent the `degree of progress' reached by each living organism or by each big set of living organisms, like historic human civilizations. Having understood this fact, human history may then be cast into the language of b-lognormals that are more and more organized in time (i.e. having smaller and smaller entropy, or smaller and smaller `chaos'), and have their peaks on the increasing GBM exponential. This exponential is thus the `trend of progress' in human history. (4) All these results also match with SETI in that the statistical Drake equation (generalization of the ordinary Drake equation to encompass statistics) leads just to the lognormal distribution as the probability distribution for the number of extra

  11. Consciousness and biological evolution.

    Science.gov (United States)

    Lindahl, B I

    1997-08-21

    It has been suggested that if the preservation and development of consciousness in the biological evolution is a result of natural selection, it is plausible that consciousness not only has been influenced by neural processes, but has had a survival value itself; and it could only have had this, if it had also been efficacious. This argument for mind-brain interaction is examined, both as the argument has been developed by William James and Karl Popper and as it has been discussed by C.D. Broad. The problem of identifying mental phenomena with certain neural phenomena is also addressed. The main conclusion of the analysis is that an explanation of the evolution of consciousness in Darwinian terms of natural selection does not rule out that consciousness may have evolved as a mere causally inert effect of the evolution of the nervous system, or that mental phenomena are identical with certain neural phenomena. However, the interactionistic theory still seems, more plausible and more fruitful for other reasons brought up in the discussion.

  12. Rapid directed evolution of stabilized proteins with cellular high-throughput encapsulation solubilization and screening (CHESS).

    Science.gov (United States)

    Yong, K J; Scott, D J

    2015-03-01

    Directed evolution is a powerful method for engineering proteins towards user-defined goals and has been used to generate novel proteins for industrial processes, biological research and drug discovery. Typical directed evolution techniques include cellular display, phage display, ribosome display and water-in-oil compartmentalization, all of which physically link individual members of diverse gene libraries to their translated proteins. This allows the screening or selection for a desired protein function and subsequent isolation of the encoding gene from diverse populations. For biotechnological and industrial applications there is a need to engineer proteins that are functional under conditions that are not compatible with these techniques, such as high temperatures and harsh detergents. Cellular High-throughput Encapsulation Solubilization and Screening (CHESS), is a directed evolution method originally developed to engineer detergent-stable G proteins-coupled receptors (GPCRs) for structural biology. With CHESS, library-transformed bacterial cells are encapsulated in detergent-resistant polymers to form capsules, which serve to contain mutant genes and their encoded proteins upon detergent mediated solubilization of cell membranes. Populations of capsules can be screened like single cells to enable rapid isolation of genes encoding detergent-stable protein mutants. To demonstrate the general applicability of CHESS to other proteins, we have characterized the stability and permeability of CHESS microcapsules and employed CHESS to generate thermostable, sodium dodecyl sulfate (SDS) resistant green fluorescent protein (GFP) mutants, the first soluble proteins to be engineered using CHESS. © 2014 Wiley Periodicals, Inc.

  13. The evolution of wealth transmission in human populations: a stochastic model

    International Nuclear Information System (INIS)

    Augustins, G; Etienne, L; Ferrer, R; Godelle, B; Rousset, F; Ferdy, J-B; Pitard, E

    2014-01-01

    Reproductive success and survival are influenced by wealth in human populations. Wealth is transmitted to offsprings and strategies of transmission vary over time and among populations, the main variation being how equally wealth is transmitted to children. Here we propose a model where we simulate both the dynamics of wealth in a population and the evolution of a trait that determines how wealth is transmitted from parents to offspring, in a darwinian context

  14. Warfare, genocide, and ethnic conflict: a Darwinian approach.

    Science.gov (United States)

    Dimijian, Gregory G

    2010-07-01

    As the 21st century dawns, I reflect on the history of humankind with growing concern about the need to understand the underlying biological and cultural roots of ethnic conflict and warfare. In the many studies of human conflict, innate biological predispositions have been neglected. This article is the third part of a series of seminars for medical residents at the University of Texas Southwestern Medical School at Dallas (see http://adarwinstudygroup.org/). The series starts with in-depth coverage of Darwinian natural and sexual selection, with examples from the domestication of animals and plants and the crisis of antibiotic resistance. The series strives to show how biology has been neglected in the study of the we-they orientation of human behavior, with its devastating consequences. The subject material is profoundly disturbing, as it looks at "human nature" and contrasts the "dark side" of human behavior with the opposite, profoundly caring and loving side.

  15. The physics of evolution

    Science.gov (United States)

    Eigen, Manfred

    1988-12-01

    The Darwinian concept of evolution through natural selection has been revised and put on a solid physical basis, in a form which applies to self-replicable macromolecules. Two new concepts are introduced: sequence space and quasi-species. Evolutionary change in the DNA- or RNA-sequence of a gene can be mapped as a trajectory in a sequence space of dimension ν, where ν corresponds to the number of changeable positions in the genomic sequence. Emphasis, however, is shifted from the single surviving wildtype, a single point in the sequence space, to the complex structure of the mutant distribution that constitutes the quasi-species. Selection is equivalent to an establishment of the quasi-species in a localized region of sequence space, subject to threshold conditions for the error rate and sequence length. Arrival of a new mutant may violate the local threshold condition and thereby lead to a displacement of the quasi-species into a different region of sequence space. This transformation is similar to a phase transition; the dynamical equations that describe the quase-species have been shown to be analogous to those of the two-dimensional Ising model of ferromagnetism. The occurrence of a selectively advantageous mutant is biased by the particulars of the quasi-species distribution, whose mutants are populated according to their fitness relative to that of the wild-type. Inasmuch as fitness regions are connected (like mountain ridges) the evolutionary trajectory is guided to regions of optimal fitness. Evolution experiments in test tubes confirm this modification of the simple chance and law nature of the Darwinian concept. The results of the theory can also be applied to the construction of a machine that provides optimal conditions for a rapid evolution of functionally active macromolecules. An introduction to the physics of molecular evolution by the author has appeared recently.1 Detailed studies of the kinetics and mechanisms of replication of RNA, the most

  16. TWO-DIMENSIONAL CELLULAR AUTOMATON MODEL FOR THE EVOLUTION OF ACTIVE REGION CORONAL PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    López Fuentes, Marcelo [Instituto de Astronomía y Física del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Klimchuk, James A., E-mail: lopezf@iafe.uba.ar [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)

    2015-02-01

    We study a two-dimensional cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their footpoints by photospheric motions. The magnetic stress accumulated between neighbor strands is released in sudden reconnection events or nanoflares that heat the plasma. We combine the CA model with the Enthalpy Based Thermal Evolution of Loops model to compute the response of the plasma to the heating events. Using the known response of the X-Ray Telescope on board Hinode, we also obtain synthetic data. The model obeys easy-to-understand scaling laws relating the output (nanoflare energy, temperature, density, intensity) to the input parameters (field strength, strand length, critical misalignment angle). The nanoflares have a power-law distribution with a universal slope of –2.5, independent of the input parameters. The repetition frequency of nanoflares, expressed in terms of the plasma cooling time, increases with strand length. We discuss the implications of our results for the problem of heating and evolution of active region coronal plasmas.

  17. Evolution of Life and SETI (Evo-SETI)

    Science.gov (United States)

    Maccone, Claudio

    When SETI scientists will be able to discover a signal or just some signs of an Extra-Terrestrial (ET) Civilization, those ETs should turn out to be technologically advanced at least as much as Humans, if not more, or much more so. Comparing the technological level of two different Civilizations is then a key issue in SETI. But at the moment we only know about the development of life on Earth over the last 3.5 billion years. We thus need to mathematically model the evolution of life on Earth (RNA to Humans) and then apply our results to other extra-solar planets to find out “where they stand” along their evolution of life. In a series of recent papers and in a book (refs. [1] through [4]) this author introduced a new statistical model embracing SETI, Darwinian Evolution and Human History into a unified statistical picture and concisely called Evo-SETI (Evolution & SETI). The relevant mathematical instruments are: 1) The statistical generalization of the Drake equation yielding the number N of communicating ET civilizations in the Galaxy. Assuming that each input variable in the Drake equation was a random variable, rather than just a pure number, N was shown to follow the lognormal probability distribution having as mean value the sum of the input mean values, and as variance the sum of the input variances (ref. [1]). 2) Geometric Brownian Motion (GBM), the stochastic process representing Evolution as the stochastic increase of the number of Species living on Earth over the last 3.5 billion years. This GBM is well-known in the mathematics of finances (Black-Sholes models). Its main features are that its probability density function (pdf) is a lognormal pdf, and its mean value is either an increasing, or, more rarely (as in the Mass Extinctions of the past) a decreasing exponential of the time. 3) The probability distributions known as b-lognormals, i.e. lognormals starting at a certain positive instant b>0 rather than at the origin. These b-lognormals were then

  18. Lamarckian evolution of the giant Mimivirus in allopatric laboratory culture on amoebae.

    Science.gov (United States)

    Colson, Philippe; Raoult, Didier

    2012-01-01

    Acanthamoeba polyphaga Mimivirus has been subcultured 150 times on germ-free amoebae. This allopatric niche is very different from that found in the natural environment, where the virus is in competition with many other organisms. In this experiment, substantial gene variability and loss occurred concurrently with the emergence of phenotypically different viruses. We sought to quantify the respective roles of Lamarckian and Darwinian evolution during this experiment. We postulated that the Mimivirus genes that were down-regulated at the beginning of the allopatric laboratory culture and inactivated after 150 passages experienced Lamarckian evolution because phenotypic modifications preceded genotypic modifications, whereas we considered that genes that were highly transcribed in the new niche but were later inactivated obeyed Darwinian rules. We used the total transcript abundances and sequences described for the genes of Mimivirus at the beginning of its laboratory life and after 150 passages in allopatric culture on Acanthamoeba spp. We found a statistically significant positive correlation between the level of gene expression at the beginning of the culture and gene inactivation during the 150 passages. In particular, the mean transcript abundance at baseline was significantly lower for inactivated genes than for unchanged genes (165 ± 589 vs. 470 ± 1,625; p allopatric laboratory culture if they were encoded by variable genes than if they were encoded by conserved genes (9 vs. 15%; p = 0.062). Finally, Lamarckian evolution represented the evolutionary process encountered by 63% of the inactivated genes. Such observations may be explained by the lower level of DNA repair of useless genes.

  19. Evolution of altruism in spatial prisoner's dilemma: Intra- and inter-cellular interactions

    Science.gov (United States)

    Yokoi, Hiroki; Uehara, Takashi; Sakata, Tomoyuki; Naito, Hiromi; Morita, Satoru; Tainaka, Kei-ichi

    2014-12-01

    Iterated prisoner's dilemma game is carried out on lattice with “colony” structure. Each cell is regarded as a colony which contains plural players with an identical strategy. Both intra- and inter-cellular interactions are assumed. In the former a player plays with all other players in the same colony, while in the latter he plays with one player each from adjacent colonies. Spatial patterns among four typical strategies exhibit various dynamics and winners. Both theory and simulation reveal that All Cooperation (AC) wins, when the members of colony or the intensity of noise increases. This result explains the evolution of altruism in animal societies, even though errors easily occur in animal communications.

  20. Zeno's paradox in quantum cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Groessing, G [Atominst. der Oesterreichischen Universitaeten, Vienna (Austria); Zeilinger, A [Inst. fuer Experimentalphysik, Univ. Innsbruck (Austria)

    1991-07-01

    The effect of Zeno's paradox in quantum theory is demonstrated with the aid of quantum mechanical cellular automata. It is shown that the degree of non-unitarity of the cellular automaton evolution and the frequency of consecutive measurements of cellular automaton states are operationally indistinguishable. (orig.).

  1. Zeno's paradox in quantum cellular automata

    International Nuclear Information System (INIS)

    Groessing, G.; Zeilinger, A.

    1991-01-01

    The effect of Zeno's paradox in quantum theory is demonstrated with the aid of quantum mechanical cellular automata. It is shown that the degree of non-unitarity of the cellular automaton evolution and the frequency of consecutive measurements of cellular automaton states are operationally indistinguishable. (orig.)

  2. Ecological fitness, genomic islands and bacterial pathogenicity: A Darwinian view of the evolution of microbes

    OpenAIRE

    Hacker, Jörg; Carniel, Elisabeth

    2001-01-01

    The compositions of bacterial genomes can be changed rapidly and dramatically through a variety of processes including horizontal gene transfer. This form of change is key to bacterial evolution, as it leads to ‘evolution in quantum leaps’. Horizontal gene transfer entails the incorporation of genetic elements transferred from another organism—perhaps in an earlier generation—directly into the genome, where they form ‘genomic islands’, i.e. blocks of DNA with signatures of mobile genetic elem...

  3. Science & Society seminar: Evolution is not only a story of genes

    CERN Multimedia

    2002-01-01

    Memes are behaviours and ideas copied from person to person by imitation. These include songs, habits, skills, inventions and ways of doing things. Darwinian evolutionary theory, which holds that genes control the traits of organisms, has traditionally explained human nature. Susan Blackmore offers a new look at evolution, and considers evolving memes as well as genes. This will be the subject of the next Science and Society seminar, 'The evolution of Meme machines', that will take place on Thursday 24 October. According to the meme idea, everything changed in human evolution when imitation first appeared because imitation let loose a new replicator, the meme. Since that time, two replicators have been driving human evolution, not one. This is why humans have such big brains, and why they alone produce and understand grammatical language, sing, dance, wear clothes and have complex cumulative cultures. Unlike other brains, human brains had to solve the problem of choosing which memes to imitate. In other wor...

  4. Conceptualizing the origin of life in terms of evolution

    Science.gov (United States)

    Takeuchi, N.; Hogeweg, P.; Kaneko, K.

    2017-11-01

    In this opinion piece, we discuss how to place evolution in the context of origin-of-life research. Our discussion starts with a popular definition: `life is a self-sustained chemical system capable of undergoing Darwinian evolution'. According to this definition, the origin of life is the same as the origin of evolution: evolution is the `end' of the origin of life. This perspective, however, has a limitation, in that the ability of evolution in and of itself is insufficient to explain the origin of life as we know it, as indicated by Spiegelman's and Lincoln and Joyce's experiments. This limitation provokes a crucial question: What conditions are required for replicating systems to evolve into life? From this perspective, the origin of life includes the emergence of life through evolution: evolution is a `means' of the origin of life. After reviewing Eigen's pioneering work on this question, we mention our ongoing work suggesting that a key condition might be conflicting multi-level evolution. Taken together, there are thus two questions regarding the origin of life: how evolution gets started, and how evolution produces life. Evolution is, therefore, at the centre of the origin of life, where the two lines of enquiry must meet. This article is part of the themed issue 'Reconceptualizing the origins of life'.

  5. Darwinism and the cultural evolution of sports.

    Science.gov (United States)

    De Block, Andreas; Dewitte, Siegfried

    2009-01-01

    This article outlines a Darwinian approach to sports that takes into account its profoundly cultural character and thereby overcomes the traditional nature-culture dichotomies in the sociology of sport. We argue that there are good reasons to view sports as culturally evolved signaling systems that serve a function similar to (biological) courtship rituals in other animals. Our approach combines the insights of evolutionary psychology, which states that biological adaptations determine the boundaries for the types of sport that are possible, and pure cultural theories, which describe the mechanism of cultural evolution without referring to sport's biological bases. Several biological and cultural factors may moderate the direct effect that signaling value has on a sport's viability or popularity. Social learning underlies many aspects of the cultural control of sports, and sports have evolved new cultural functions more-or-less unrelated to mate choice as cultural evolution itself became important in humans.

  6. Breeding novel solutions in the brain: a model of Darwinian neurodynamics [version 1; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    András Szilágyi

    2016-09-01

    Full Text Available Background: The fact that surplus connections and neurons are pruned during development is well established. We complement this selectionist picture by a proof-of-principle model of evolutionary search in the brain, that accounts for new variations in theory space. We present a model for Darwinian evolutionary search for candidate solutions in the brain. Methods: We combine known components of the brain – recurrent neural networks (acting as attractors, the action selection loop and implicit working memory – to provide the appropriate Darwinian architecture. We employ a population of attractor networks with palimpsest memory. The action selection loop is employed with winners-share-all dynamics to select for candidate solutions that are transiently stored in implicit working memory. Results: We document two processes: selection of stored solutions and evolutionary search for novel solutions. During the replication of candidate solutions attractor networks occasionally produce recombinant patterns, increasing variation on which selection can act. Combinatorial search acts on multiplying units (activity patterns with hereditary variation and novel variants appear due to (i noisy recall of patterns from the attractor networks, (ii noise during transmission of candidate solutions as messages between networks, and, (iii spontaneously generated, untrained patterns in spurious attractors. Conclusions: Attractor dynamics of recurrent neural networks can be used to model Darwinian search. The proposed architecture can be used for fast search among stored solutions (by selection and for evolutionary search when novel candidate solutions are generated in successive iterations. Since all the suggested components are present in advanced nervous systems, we hypothesize that the brain could implement a truly evolutionary combinatorial search system, capable of generating novel variants.

  7. Breeding novel solutions in the brain: a model of Darwinian neurodynamics [version 2; referees: 1 approved, 2 approved with reservations

    Directory of Open Access Journals (Sweden)

    András Szilágyi

    2017-06-01

    Full Text Available Background: The fact that surplus connections and neurons are pruned during development is well established. We complement this selectionist picture by a proof-of-principle model of evolutionary search in the brain, that accounts for new variations in theory space. We present a model for Darwinian evolutionary search for candidate solutions in the brain. Methods: We combine known components of the brain – recurrent neural networks (acting as attractors, the action selection loop and implicit working memory – to provide the appropriate Darwinian architecture. We employ a population of attractor networks with palimpsest memory. The action selection loop is employed with winners-share-all dynamics to select for candidate solutions that are transiently stored in implicit working memory. Results: We document two processes: selection of stored solutions and evolutionary search for novel solutions. During the replication of candidate solutions attractor networks occasionally produce recombinant patterns, increasing variation on which selection can act. Combinatorial search acts on multiplying units (activity patterns with hereditary variation and novel variants appear due to (i noisy recall of patterns from the attractor networks, (ii noise during transmission of candidate solutions as messages between networks, and, (iii spontaneously generated, untrained patterns in spurious attractors. Conclusions: Attractor dynamics of recurrent neural networks can be used to model Darwinian search. The proposed architecture can be used for fast search among stored solutions (by selection and for evolutionary search when novel candidate solutions are generated in successive iterations. Since all the suggested components are present in advanced nervous systems, we hypothesize that the brain could implement a truly evolutionary combinatorial search system, capable of generating novel variants.

  8. Wireless Cellular Mobile Communications

    OpenAIRE

    Zalud, V.

    2002-01-01

    In this article is briefly reviewed the history of wireless cellular mobile communications, examined the progress in current second generation (2G) cellular standards and discussed their migration to the third generation (3G). The European 2G cellular standard GSM and its evolution phases GPRS and EDGE are described somewhat in detail. The third generation standard UMTS taking up on GSM/GPRS core network and equipped with a new advanced access network on the basis of code division multiple ac...

  9. Progress in life's history: Linking Darwinism and palaeontology in Britain, 1860-1914.

    Science.gov (United States)

    Manias, Chris

    2017-12-01

    This paper examines the tension between Darwinian evolution and palaeontological research in Britain in the 1860-1914 period, looking at how three key promoters of Darwinian thinking - Thomas Henry Huxley, Edwin Ray Lankester and Alfred Russell Wallace - integrated palaeontological ideas and narratives of life's history into their public presentations of evolutionary theory. It shows how engagement with palaeontological science was an important part of the promotion of evolutionary ideas in Britain, which often bolstered notions that evolution depended upon progress and development along a wider plan. While often critical of some of the non-Darwinian concepts of evolution professed by many contemporary palaeontologists, and frequently citing the 'imperfection' of the fossil record itself, Darwinian thinkers nevertheless engaged extensively with palaeontology to develop evolutionary narratives informed by notions of improvement and progress within the natural world. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  10. Origin of Evolution versus Origin of Life: A Shift of Paradigm

    Directory of Open Access Journals (Sweden)

    Marc Tessera

    2011-06-01

    Full Text Available The question of the primordial ancestor must be approached through the search for the origin of evolution, not through the search for the origin of life. There is a major issue with the concept of life because it is impossible to define, thus is not a scientific but a metaphysical concept. On the contrary, evolution may be defined by as few as three conditions. These do not necessarily involve biopolymers. However, such an approach must give clues to explain the emergence of distinct lineages to allow Darwinian natural selection. A plausible solution exists within an autotrophic lipidic vesicle-based model that is presented. The model requires the existence of hydrothermal sites such as the Lost City Hydrothermal Field leading to specific constraints. For this reason Mars and Europa may be questioned as possible cradles of evolution. If we replace the search for the origin of life by the one for the origin of evolution our priority first is to find a consensus on the minimal conditions that would allow evolution to emerge and persist anywhere in the universe.

  11. "Plants that Remind Me of Home": Collecting, Plant Geography, and a Forgotten Expedition in the Darwinian Revolution.

    Science.gov (United States)

    Hung, Kuang-Chi

    2017-02-01

    In 1859, Harvard botanist Asa Gray (1810-1888) published an essay of what he called "the abstract of Japan botany." In it, he applied Charles Darwin's evolutionary theory to explain why strong similarities could be found between the flora of Japan and that of eastern North America, which provoked his famous debate with Louis Agassiz (1807-1873) and initiated Gray's efforts to secure a place for Darwinian biology in the American sciences. Notably, although the Gray-Agassiz debate has become one of the most thoroughly studied scientific debates, historians of science remain unable to answer one critical question: How was Gray able to acquire specimens from Japan? Making use of previously unknown archival materials, this article scrutinizes the institutional, instrumental, financial, and military settings that enabled Gray's collector, Charles Wright (1811-1885), to travel to Japan, as well as examine Wright's collecting practices in Japan. I argue that it is necessary to examine Gray's diagnosis of Japan's flora and the subsequent debate about it from the viewpoint of field sciences. The field-centered approach not only unveils an array of historical significances that have been overshadowed by the analytical framework of the Darwinian revolution and the reception of Darwinism, but also places a seemingly domestic incident in a transnational context.

  12. Evolution and the Growth Process: Natural Selection of Entrepreneurial Traits.

    Science.gov (United States)

    Galor, Oded; Michalopoulos, Stelios

    2012-03-01

    This research suggests that a Darwinian evolution of entrepreneurial spirit played a significant role in the process of economic development and the dynamics of inequality within and across societies. The study argues that entrepreneurial spirit evolved non-monotonically in the course of human history. In early stages of development, risk-tolerant, growth promoting traits generated an evolutionary advantage and their increased representation accelerated the pace of technological progress and the process of economic development. In mature stages of development, however, risk-averse traits gained an evolutionary advantage, diminishing the growth potential of advanced economies and contributing to convergence in economic growth across countries.

  13. The Influence of Darwinian Ideas on Greek Literary Writers of the Late Nineteenth and Early Twentieth Centuries: The Case of Emmanuel Roidis

    Directory of Open Access Journals (Sweden)

    Maria Zarimis

    2008-11-01

    Full Text Available Darwin's works provoked an enormous response in many disciplines including the literary world. This paper presents a portion of my doctoral thesis3, which responds to a blind spot in Greek literary scholarship on evolutionary ideas in comparison to other Western countries. Little work to date focuses on modern Greek writers's responses to Darwinian and other evolutionary ideas. This paper explores the impact of Darwin in selected writings of Emmanuel Roidis and how Roidis satirised Darwinism in his essays and short stories, contributing to the Darwinian discourse on "man's place in nature" and by placing humanity on the same continuum as other primates. The year 2009 marks the 200th anniversary of Darwin's birth and the 150th anniversary of the first publication of his The Origin of Species. It is timely, then, to consider Darwin's impact on modern Greek literature.

  14. Children of time: the extended synthesis and major metaphors of evolution

    Directory of Open Access Journals (Sweden)

    Daniel R. Brooks

    2012-12-01

    Full Text Available It is time for an expansion and enrichment of evolutionary theory. The "back to the future" proposal contained herein is based on three postulates: 1 Neo-Darwinism is too impoverished for this task; 2 its predecessor, Darwinism, contained the necessary breadth of vision and metaphor to be the basis for an inclusive and unifying theory of biology; and 3 the necessary framework for this new stage in the evolution of evolutionary theory is largely in place. We make our case through the use of a number of metaphorical dualisms designed to help focus discussions toward a more cooperative and productive approach to the study of living systems. Along the way, we suggest a number of self-induced paradoxes in neo-Darwinian accounts of evolution that are resolved by our perspective.

  15. Critical dynamics in the evolution of stochastic strategies for the iterated prisoner's dilemma.

    Directory of Open Access Journals (Sweden)

    Dimitris Iliopoulos

    2010-10-01

    Full Text Available The observed cooperation on the level of genes, cells, tissues, and individuals has been the object of intense study by evolutionary biologists, mainly because cooperation often flourishes in biological systems in apparent contradiction to the selfish goal of survival inherent in Darwinian evolution. In order to resolve this paradox, evolutionary game theory has focused on the Prisoner's Dilemma (PD, which incorporates the essence of this conflict. Here, we encode strategies for the iterated Prisoner's Dilemma (IPD in terms of conditional probabilities that represent the response of decision pathways given previous plays. We find that if these stochastic strategies are encoded as genes that undergo Darwinian evolution, the environmental conditions that the strategies are adapting to determine the fixed point of the evolutionary trajectory, which could be either cooperation or defection. A transition between cooperative and defective attractors occurs as a function of different parameters such as mutation rate, replacement rate, and memory, all of which affect a player's ability to predict an opponent's behavior. These results imply that in populations of players that can use previous decisions to plan future ones, cooperation depends critically on whether the players can rely on facing the same strategies that they have adapted to. Defection, on the other hand, is the optimal adaptive response in environments that change so quickly that the information gathered from previous plays cannot usefully be integrated for a response.

  16. Cellular Automata and the Humanities.

    Science.gov (United States)

    Gallo, Ernest

    1994-01-01

    The use of cellular automata to analyze several pre-Socratic hypotheses about the evolution of the physical world is discussed. These hypotheses combine characteristics of both rigorous and metaphoric language. Since the computer demands explicit instructions for each step in the evolution of the automaton, such models can reveal conceptual…

  17. Monkeys into Men and Men into Monkeys: Chance and Contingency in the Evolution of Man, Mind and Morals in Charles Kingsley's Water Babies.

    Science.gov (United States)

    Hale, Piers J

    2013-01-01

    The nineteenth century theologian, author and poet Charles Kingsley was a notable populariser of Darwinian evolution. He championed Darwin's cause and that of honesty in science for more than a decade from 1859 to 1871. Kingsley's interpretation of evolution shaped his theology, his politics and his views on race. The relationship between men and apes set the context for Kingsley's consideration of these issues. Having defended Darwin for a decade in 1871 Kingsley was dismayed to read Darwin's account of the evolution of morals in Descent of Man. He subsequently distanced himself from Darwin's conclusions even though he remained an ardent evolutionist until his death in 1875.

  18. Directed Evolution of Proteins through In Vitro Protein Synthesis in Liposomes

    Directory of Open Access Journals (Sweden)

    Takehiro Nishikawa

    2012-01-01

    Full Text Available Directed evolution of proteins is a technique used to modify protein functions through “Darwinian selection.” In vitro compartmentalization (IVC is an in vitro gene screening system for directed evolution of proteins. IVC establishes the link between genetic information (genotype and the protein translated from the information (phenotype, which is essential for all directed evolution methods, by encapsulating both in a nonliving microcompartment. Herein, we introduce a new liposome-based IVC system consisting of a liposome, the protein synthesis using recombinant elements (PURE system and a fluorescence-activated cell sorter (FACS used as a microcompartment, in vitro protein synthesis system, and high-throughput screen, respectively. Liposome-based IVC is characterized by in vitro protein synthesis from a single copy of a gene in a cell-sized unilamellar liposome and quantitative functional evaluation of the synthesized proteins. Examples of liposome-based IVC for screening proteins such as GFP and β-glucuronidase are described. We discuss the future directions for this method and its applications.

  19. The rule of declining adaptability in microbial evolution experiments

    Science.gov (United States)

    Couce, Alejandro; Tenaillon, Olivier A.

    2015-01-01

    One of the most recurrent observations after two decades of microbial evolution experiments regards the dynamics of fitness change. In a given environment, low-fitness genotypes are recurrently observed to adapt faster than their more fit counterparts. Since adaptation is the main macroscopic outcome of Darwinian evolution, studying its patterns of change could potentially provide insight into key issues of evolutionary theory, from fixation dynamics to the genetic architecture of organisms. Here, we re-analyze several published datasets from experimental evolution with microbes and show that, despite large differences in the origin of the data, a pattern of inverse dependence of adaptability with fitness clearly emerges. In quantitative terms, it is remarkable to observe little if any degree of idiosyncrasy across systems as diverse as virus, bacteria and yeast. The universality of this phenomenon suggests that its emergence might be understood from general principles, giving rise to the exciting prospect that evolution might be statistically predictable at the macroscopic level. We discuss these possibilities in the light of the various theories of adaptation that have been proposed and delineate future directions of research. PMID:25815007

  20. Inventing an arsenal: adaptive evolution and neofunctionalization of snake venom phospholipase A2 genes

    Directory of Open Access Journals (Sweden)

    Lynch Vincent J

    2007-01-01

    Full Text Available Abstract Background Gene duplication followed by functional divergence has long been hypothesized to be the main source of molecular novelty. Convincing examples of neofunctionalization, however, remain rare. Snake venom phospholipase A2 genes are members of large multigene families with many diverse functions, thus they are excellent models to study the emergence of novel functions after gene duplications. Results Here, I show that positive Darwinian selection and neofunctionalization is common in snake venom phospholipase A2 genes. The pattern of gene duplication and positive selection indicates that adaptive molecular evolution occurs immediately after duplication events as novel functions emerge and continues as gene families diversify and are refined. Surprisingly, adaptive evolution of group-I phospholipases in elapids is also associated with speciation events, suggesting adaptation of the phospholipase arsenal to novel prey species after niche shifts. Mapping the location of sites under positive selection onto the crystal structure of phospholipase A2 identified regions evolving under diversifying selection are located on the molecular surface and are likely protein-protein interactions sites essential for toxin functions. Conclusion These data show that increases in genomic complexity (through gene duplications can lead to phenotypic complexity (venom composition and that positive Darwinian selection is a common evolutionary force in snake venoms. Finally, regions identified under selection on the surface of phospholipase A2 enzymes are potential candidate sites for structure based antivenin design.

  1. Origin of symbol-using systems: speech, but not sign, without the semantic urge.

    Science.gov (United States)

    Sereno, Martin I

    2014-09-19

    Natural language--spoken and signed--is a multichannel phenomenon, involving facial and body expression, and voice and visual intonation that is often used in the service of a social urge to communicate meaning. Given that iconicity seems easier and less abstract than making arbitrary connections between sound and meaning, iconicity and gesture have often been invoked in the origin of language alongside the urge to convey meaning. To get a fresh perspective, we critically distinguish the origin of a system capable of evolution from the subsequent evolution that system becomes capable of. Human language arose on a substrate of a system already capable of Darwinian evolution; the genetically supported uniquely human ability to learn a language reflects a key contact point between Darwinian evolution and language. Though implemented in brains generated by DNA symbols coding for protein meaning, the second higher-level symbol-using system of language now operates in a world mostly decoupled from Darwinian evolutionary constraints. Examination of Darwinian evolution of vocal learning in other animals suggests that the initial fixation of a key prerequisite to language into the human genome may actually have required initially side-stepping not only iconicity, but the urge to mean itself. If sign languages came later, they would not have faced this constraint.

  2. Does constructive neutral evolution play an important role in the origin of cellular complexity? Making sense of the origins and uses of biological complexity.

    Science.gov (United States)

    Speijer, Dave

    2011-05-01

    Recently, constructive neutral evolution has been touted as an important concept for the understanding of the emergence of cellular complexity. It has been invoked to help explain the development and retention of, amongst others, RNA splicing, RNA editing and ribosomal and mitochondrial respiratory chain complexity. The theory originated as a welcome explanation of isolated small scale cellular idiosyncrasies and as a reaction to 'overselectionism'. Here I contend, that in its extended form, it has major conceptual problems, can not explain observed patterns of complex processes, is too easily dismissive of alternative selectionist models, underestimates the creative force of complexity as such, and--if seen as a major evolutionary mechanism for all organisms--could stifle further thought regarding the evolution of highly complex biological processes. Copyright © 2011 WILEY Periodicals, Inc.

  3. On the thermodynamics of multilevel evolution.

    Science.gov (United States)

    Tessera, Marc; Hoelzer, Guy A

    2013-09-01

    Biodiversity is hierarchically structured both phylogenetically and functionally. Phylogenetic hierarchy is understood as a product of branching organic evolution as described by Darwin. Ecosystem biologists understand some aspects of functional hierarchy, such as food web architecture, as a product of evolutionary ecology; but functional hierarchy extends to much lower scales of organization than those studied by ecologists. We argue that the more general use of the term "evolution" employed by physicists and applied to non-living systems connects directly to the narrow biological meaning. Physical evolution is best understood as a thermodynamic phenomenon, and this perspective comfortably includes all of biological evolution. We suggest four dynamical factors that build on each other in a hierarchical fashion and set the stage for the Darwinian evolution of biological systems: (1) the entropic erosion of structure; (2) the construction of dissipative systems; (3) the reproduction of growing systems and (4) the historical memory accrued to populations of reproductive agents by the acquisition of hereditary mechanisms. A particular level of evolution can underpin the emergence of higher levels, but evolutionary processes persist at each level in the hierarchy. We also argue that particular evolutionary processes can occur at any level of the hierarchy where they are not obstructed by material constraints. This theoretical framework provides an extensive basis for understanding natural selection as a multilevel process. The extensive literature on thermodynamics in turn provides an important advantage to this perspective on the evolution of higher levels of organization, such as the evolution of altruism that can accompany the emergence of social organization. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. Evolution and the Growth Process: Natural Selection of Entrepreneurial Traits*

    Science.gov (United States)

    Galor, Oded; Michalopoulos, Stelios

    2013-01-01

    This research suggests that a Darwinian evolution of entrepreneurial spirit played a significant role in the process of economic development and the dynamics of inequality within and across societies. The study argues that entrepreneurial spirit evolved non-monotonically in the course of human history. In early stages of development, risk-tolerant, growth promoting traits generated an evolutionary advantage and their increased representation accelerated the pace of technological progress and the process of economic development. In mature stages of development, however, risk-averse traits gained an evolutionary advantage, diminishing the growth potential of advanced economies and contributing to convergence in economic growth across countries. PMID:25089059

  5. Teaching Evolution: A Heuristic Study of Personal and Cultural Dissonance

    Science.gov (United States)

    Grimes, Larry G.

    Darwinian evolution is a robustly supported scientific theory. Yet creationists continue to challenge its teaching in American public schools. Biology teachers in all 50 states are responsible for teaching science content standards that include evolution. As products of their backgrounds and affiliations teachers bring personal attitudes and beliefs to their teaching. The purpose of this study was to explore how biology teachers perceive, describe, and value their teaching of evolution. This research question was explored through a heuristic qualitative methodology. Eight veteran California high school biology teachers were queried as to their beliefs, perceptions, experiences and practices of teaching evolution. Both personal and professional documents were collected. Data was presented in the form of biographical essays that highlight teachers' backgrounds, experiences, perspectives and practices of teaching evolution. Of special interest was how they describe pressure over teaching evolution during a decade of standards and No Child Left Behind high-stakes testing mandates. Five common themes emerged. Standards have increased the overall amount of evolution that is taught. High-stakes testing has decreased the depth at which evolution is taught. Teacher belief systems strongly influence how evolution is taught. Fear of creationist challenges effect evolution teaching strategies. And lastly, concern over the potential effects of teaching evolution on student worldviews was mixed. Three categories of teacher concern over the potential impact of evolution on student worldviews were identified: Concerned, Strategist, and Carefree. In the final analysis teacher beliefs and attitudes still appeared to he the most important factor influencing how evolution is taught.

  6. Prebiological evolution and the metabolic origins of life.

    Science.gov (United States)

    Pratt, Andrew J

    2011-01-01

    The chemoton model of cells posits three subsystems: metabolism, compartmentalization, and information. A specific model for the prebiological evolution of a reproducing system with rudimentary versions of these three interdependent subsystems is presented. This is based on the initial emergence and reproduction of autocatalytic networks in hydrothermal microcompartments containing iron sulfide. The driving force for life was catalysis of the dissipation of the intrinsic redox gradient of the planet. The codependence of life on iron and phosphate provides chemical constraints on the ordering of prebiological evolution. The initial protometabolism was based on positive feedback loops associated with in situ carbon fixation in which the initial protometabolites modified the catalytic capacity and mobility of metal-based catalysts, especially iron-sulfur centers. A number of selection mechanisms, including catalytic efficiency and specificity, hydrolytic stability, and selective solubilization, are proposed as key determinants for autocatalytic reproduction exploited in protometabolic evolution. This evolutionary process led from autocatalytic networks within preexisting compartments to discrete, reproducing, mobile vesicular protocells with the capacity to use soluble sugar phosphates and hence the opportunity to develop nucleic acids. Fidelity of information transfer in the reproduction of these increasingly complex autocatalytic networks is a key selection pressure in prebiological evolution that eventually leads to the selection of nucleic acids as a digital information subsystem and hence the emergence of fully functional chemotons capable of Darwinian evolution.

  7. Dynamics of Tumor Heterogeneity Derived from Clonal Karyotypic Evolution

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    Ashley M. Laughney

    2015-08-01

    Full Text Available Numerical chromosomal instability is a ubiquitous feature of human neoplasms. Due to experimental limitations, fundamental characteristics of karyotypic changes in cancer are poorly understood. Using an experimentally inspired stochastic model, based on the potency and chromosomal distribution of oncogenes and tumor suppressor genes, we show that cancer cells have evolved to exist within a narrow range of chromosome missegregation rates that optimizes phenotypic heterogeneity and clonal survival. Departure from this range reduces clonal fitness and limits subclonal diversity. Mapping of the aneuploid fitness landscape reveals a highly favorable, commonly observed, near-triploid state onto which evolving diploid- and tetraploid-derived populations spontaneously converge, albeit at a much lower fitness cost for the latter. Finally, by analyzing 1,368 chromosomal translocation events in five human cancers, we find that karyotypic evolution also shapes chromosomal translocation patterns by selecting for more oncogenic derivative chromosomes. Thus, chromosomal instability can generate the heterogeneity required for Darwinian tumor evolution.

  8. Environmental Adaptation from the Origin of Life to the Last Universal Common Ancestor

    Science.gov (United States)

    Cantine, Marjorie D.; Fournier, Gregory P.

    2018-03-01

    Extensive fundamental molecular and biological evolution took place between the prebiotic origins of life and the state of the Last Universal Common Ancestor (LUCA). Considering the evolutionary innovations between these two endpoints from the perspective of environmental adaptation, we explore the hypothesis that LUCA was temporally, spatially, and environmentally distinct from life's earliest origins in an RNA world. Using this lens, we interpret several molecular biological features as indicating an environmental transition between a cold, radiation-shielded origin of life and a mesophilic, surface-dwelling LUCA. Cellularity provides motility and permits Darwinian evolution by connecting genetic material and its products, and thus establishing heredity and lineage. Considering the importance of compartmentalization and motility, we propose that the early emergence of cellularity is required for environmental dispersal and diversification during these transitions. Early diversification and the emergence of ecology before LUCA could be an important pre-adaptation for life's persistence on a changing planet.

  9. Bacterial flagella and Type III secretion: case studies in the evolution of complexity.

    Science.gov (United States)

    Pallen, M J; Gophna, U

    2007-01-01

    Bacterial flagella at first sight appear uniquely sophisticated in structure, so much so that they have even been considered 'irreducibly complex' by the intelligent design movement. However, a more detailed analysis reveals that these remarkable pieces of molecular machinery are the product of processes that are fully compatible with Darwinian evolution. In this chapter we present evidence for such processes, based on a review of experimental studies, molecular phylogeny and microbial genomics. Several processes have played important roles in flagellar evolution: self-assembly of simple repeating subunits, gene duplication with subsequent divergence, recruitment of elements from other systems ('molecular bricolage'), and recombination. We also discuss additional tentative new assignments of homology (FliG with MgtE, FliO with YscJ). In conclusion, rather than providing evidence of intelligent design, flagellar and non-flagellar Type III secretion systems instead provide excellent case studies in the evolution of complex systems from simpler components.

  10. Does constructive neutral evolution play an important role in the origin of cellular complexity? Making sense of the origins and uses of biological complexity

    NARCIS (Netherlands)

    Speijer, Dave

    2011-01-01

    Recently, constructive neutral evolution has been touted as an important concept for the understanding of the emergence of cellular complexity. It has been invoked to help explain the development and retention of, amongst others, RNA splicing, RNA editing and ribosomal and mitochondrial respiratory

  11. A conceptual framework for the evolutionary origins of multicellularity

    International Nuclear Information System (INIS)

    Libby, Eric; B Rainey, Paul

    2013-01-01

    The evolution of multicellular organisms from unicellular counterparts involved a transition in Darwinian individuality from single cells to groups. A particular challenge is to understand the nature of the earliest groups, the causes of their evolution, and the opportunities for emergence of Darwinian properties. Here we outline a conceptual framework based on a logical set of possible pathways for evolution of the simplest self-replicating groups. Central to these pathways is the recognition of a finite number of routes by which genetic information can be transmitted between individual cells and groups. We describe the form and organization of each primordial group state and consider factors affecting persistence and evolution of the nascent multicellular forms. Implications arising from our conceptual framework become apparent when attempting to partition fitness effects at individual and group levels. These are discussed with reference to the evolutionary emergence of individuality and its manifestation in extant multicellular life—including those of marginal Darwinian status. (paper)

  12. Quantitative Clinical Imaging Methods for Monitoring Intratumoral Evolution.

    Science.gov (United States)

    Kim, Joo Yeun; Gatenby, Robert A

    2017-01-01

    regional dynamics so that the internal diversity of tumors is the net result of complex multiscale somatic Darwinian interactions.Methods in landscape ecology harness Darwinian dynamics to link the environmental properties of a given region to the local populations which are assumed to represent maximally fit phenotypes within those conditions. Consider a common task of a landscape ecologist: defining the spatial distribution of species in a large region, e.g., in a satellite image. Clearly the most accurate approach requires a meter by meter survey of the multiple square kilometers in the region of interest. However, this is both impractical and potentially destructive. Instead, landscape ecology breaks the task into component parts relying on the Darwinian interdependence of environmental properties and fitness of specific species' phenotypic and genotypic properties. First, the satellite map is carefully analyzed to define the number and distribution of habitats. Then the species distribution in a representative sampling of each habitat is empirically determined. Ultimately, this permits sufficient bridging of spatial scales to accurately predict spatial distribution of plant and animal species within large regions.Currently, identifying intratumoral subpopulations requires detailed histological and molecular studies that are expensive and time consuming. Furthermore, this method is subject to sampling bias, is invasive for vital organs such as the brain, and inherently destructive precluding repeated assessments for monitoring post-treatment response and proteogenomic evolution. In contrast, modern cross-sectional imaging can interrogate the entire tumor noninvasively, allowing repeated analysis without disrupting the region of interest. In particular, magnetic resonance imaging (MRI) provides exceptional spatial resolution and generates signals that are unique to the molecular constituents of tissue. Here we propose that MRI scans may be the equivalent of satellite

  13. Prisoner's Dilemma cellular automata revisited: evolution of cooperation under environmental pressure

    Science.gov (United States)

    Alonso, J.; Fernández, A.; Fort, H.

    2006-06-01

    We propose an extension of the evolutionary Prisoner's Dilemma cellular automata, introduced by Nowak and May (1992 Nature 359 826), in which the pressure of the environment is taken into account. This is implemented by requiring that individuals need to collect a minimum score Umin, representing indispensable resources (nutrients, energy, money, etc) to prosper in this environment. So the agents, instead of evolving just by adopting the behaviour of the most successful neighbour (who got Umsn), also take into account if Umsn is above or below the threshold Umin. If Umsnevolution of cooperation for payoffs for which defection was the rule (as happens, for example, when the sucker's payoff is much worse than the punishment for mutual defection). We also analyse a more sophisticated version of this model in which the selective rule is supplemented with a 'win-stay, lose-shift' criterion. The cluster structure is analysed, and for this more complex version we found power-law scaling for a restricted region in the parameter space.

  14. Statistical mechanics of cellular automata

    International Nuclear Information System (INIS)

    Wolfram, S.

    1983-01-01

    Cellular automata are used as simple mathematical models to investigate self-organization in statistical mechanics. A detailed analysis is given of ''elementary'' cellular automata consisting of a sequence of sites with values 0 or 1 on a line, with each site evolving deterministically in discrete time steps according to p definite rules involving the values of its nearest neighbors. With simple initial configurations, the cellular automata either tend to homogeneous states, or generate self-similar patterns with fractal dimensions approx. =1.59 or approx. =1.69. With ''random'' initial configurations, the irreversible character of the cellular automaton evolution leads to several self-organization phenomena. Statistical properties of the structures generated are found to lie in two universality classes, independent of the details of the initial state or the cellular automaton rules. More complicated cellular automata are briefly considered, and connections with dynamical systems theory and the formal theory of computation are discussed

  15. The Gradual Evolution of Language

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    Michael C. Corballis

    2014-12-01

    Full Text Available Language is commonly held to be unique to humans, and to have emerged suddenly in a single “great leap forward” within the past 100,000 years. The view is profoundly anti-Darwinian, and I propose instead a framework for understanding how language might have evolved incrementally from our primate heritage. One major proposition is that language evolved from manual action, with vocalization emerging as the dominant mode late in hominin evolution. The second proposition has to do with the role of language as a means of communicating about events displaced in space and time from the present. Some have argued that mental time travel itself is unique to human, which might explain why language itself is uniquely human. I argue instead that mental time travel has ancient evolutionary origins, and gradually assumed narrative-like properties during the Pleistocene, when language itself began to take shape.

  16. Hominid evolution: genetics versus memetics

    Science.gov (United States)

    Carter, Brandon

    2012-01-01

    The last few million years on planet Earth have witnessed two remarkable phases of hominid development, starting with a phase of biological evolution characterized by rather rapid increase of the size of the brain. This has been followed by a phase of even more rapid technological evolution and concomitant expansion of the size of the population that began when our own particular ‘sapiens’ species emerged, just a few hundred thousand years ago. The present investigation exploits the analogy between the neo-Darwinian genetic evolution mechanism governing the first phase, and the memetic evolution mechanism governing the second phase. From the outset of the latter until very recently - about the year 2000 - the growth of the global population N was roughly governed by an equation of the form dN/Ndt=N/T*, in which T* is a coefficient introduced (in 1960) by von Foerster, who evaluated it empirically as about 200 000 million years. It is shown here how the value of this hitherto mysterious timescale governing the memetic phase is explicable in terms of what happened in the preceding genetic phase. The outcome is that the order of magnitude of the Foerster timescale can be accounted for as the product of the relevant (human) generation timescale, about 20 years, with the number of bits of information in the genome, of the order of 10 000 million. Whereas the origin of our ‘homo’ genus may well have involved an evolutionary hard step, it transpires that the emergence of our particular ‘sapiens’ species was rather an automatic process.

  17. Repeated evolution of camouflage in speciose desert rodents.

    Science.gov (United States)

    Boratyński, Zbyszek; Brito, José C; Campos, João C; Cunha, José L; Granjon, Laurent; Mappes, Tapio; Ndiaye, Arame; Rzebik-Kowalska, Barbara; Serén, Nina

    2017-06-14

    There are two main factors explaining variation among species and the evolution of characters along phylogeny: adaptive change, including phenotypic and genetic responses to selective pressures, and phylogenetic inertia, or the resemblance between species due to shared phylogenetic history. Phenotype-habitat colour match, a classic Darwinian example of the evolution of camouflage (crypsis), offers the opportunity to test the importance of historical versus ecological mechanisms in shaping phenotypes among phylogenetically closely related taxa. To assess it, we investigated fur (phenotypic data) and habitat (remote sensing data) colourations, along with phylogenetic information, in the species-rich Gerbillus genus. Overall, we found a strong phenotype-habitat match, once the phylogenetic signal is taken into account. We found that camouflage has been acquired and lost repeatedly in the course of the evolutionary history of Gerbillus. Our results suggest that fur colouration and its covariation with habitat is a relatively labile character in mammals, potentially responding quickly to selection. Relatively unconstrained and substantial genetic basis, as well as structural and functional independence from other fitness traits of mammalian colouration might be responsible for that observation.

  18. Cultural transmission and the evolution of human behaviour: a general approach based on the Price equation.

    Science.gov (United States)

    El Mouden, C; André, J-B; Morin, O; Nettle, D

    2014-02-01

    Transmitted culture can be viewed as an inheritance system somewhat independent of genes that is subject to processes of descent with modification in its own right. Although many authors have conceptualized cultural change as a Darwinian process, there is no generally agreed formal framework for defining key concepts such as natural selection, fitness, relatedness and altruism for the cultural case. Here, we present and explore such a framework using the Price equation. Assuming an isolated, independently measurable culturally transmitted trait, we show that cultural natural selection maximizes cultural fitness, a distinct quantity from genetic fitness, and also that cultural relatedness and cultural altruism are not reducible to or necessarily related to their genetic counterparts. We show that antagonistic coevolution will occur between genes and culture whenever cultural fitness is not perfectly aligned with genetic fitness, as genetic selection will shape psychological mechanisms to avoid susceptibility to cultural traits that bear a genetic fitness cost. We discuss the difficulties with conceptualizing cultural change using the framework of evolutionary theory, the degree to which cultural evolution is autonomous from genetic evolution, and the extent to which cultural change should be seen as a Darwinian process. We argue that the nonselection components of evolutionary change are much more important for culture than for genes, and that this and other important differences from the genetic case mean that different approaches and emphases are needed for cultural than genetic processes. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  19. Simulation Modeling by Classification of Problems: A Case of Cellular Manufacturing

    International Nuclear Information System (INIS)

    Afiqah, K N; Mahayuddin, Z R

    2016-01-01

    Cellular manufacturing provides good solution approach to manufacturing area by applying Group Technology concept. The evolution of cellular manufacturing can enhance performance of the cell and to increase the quality of the product manufactured but it triggers other problem. Generally, this paper highlights factors and problems which emerge commonly in cellular manufacturing. The aim of the research is to develop a thorough understanding of common problems in cellular manufacturing. A part from that, in order to find a solution to the problems exist using simulation technique, this classification framework is very useful to be adapted during model building. Biology evolution tool was used in the research in order to classify the problems emerge. The result reveals 22 problems and 25 factors using cladistic technique. In this research, the expected result is the cladogram established based on the problems in cellular manufacturing gathered. (paper)

  20. The Intracellular Destiny of the Protein Corona: A Study on its Cellular Internalization and Evolution.

    Science.gov (United States)

    Bertoli, Filippo; Garry, David; Monopoli, Marco P; Salvati, Anna; Dawson, Kenneth A

    2016-11-22

    It has been well established that the early stages of nanoparticle-cell interactions are governed, at least in part, by the layer of proteins and other biomolecules adsorbed and slowly exchanged with the surrounding biological media (biomolecular corona). Subsequent to membrane interactions, nanoparticles are typically internalized into the cell and trafficked along defined pathways such as, in many cases, the endolysosomal pathway. Indeed, if the original corona is partially retained on the nanoparticle surface, the biomolecules in this layer may play an important role in determining subsequent cellular processing. In this work, using a combination of organelle separation and fluorescence labeling of the initial extracellular corona, we clarify its intracellular evolution as nanoparticles travel within the cell. We show that specific proteins present in the original protein corona are retained on the nanoparticles until they accumulate in lysosomes, and, once there, they are degraded. We also report on how different bare surfaces (amino and carboxyl modified) affect the details of this evolution. One overarching discovery is that the same serum proteins can exhibit different intracellular processing when carried inside cells by nanoparticles, as components of their corona, compared to what is observed when they are transported freely from the extracellular medium.

  1. Near neutrality: leading edge of the neutral theory of molecular evolution.

    Science.gov (United States)

    Hughes, Austin L

    2008-01-01

    The nearly neutral theory represents a development of Kimura's neutral theory of molecular evolution that makes testable predictions that go beyond a mere null model. Recent evidence has strongly supported several of these predictions, including the prediction that slightly deleterious variants will accumulate in a species that has undergone a severe bottleneck or in cases where recombination is reduced or absent. Because bottlenecks often occur in speciation and slightly deleterious mutations in coding regions will usually be nonsynonymous, we should expect that the ratio of nonsynonymous to synonymous fixed differences between species should often exceed the ratio of nonsynonymous to synonymous polymorphisms within species. Many data support this prediction, although they have often been wrongly interpreted as evidence for positive Darwinian selection. The use of conceptually flawed tests for positive selection has become widespread in recent years, seriously harming the quest for an understanding of genome evolution. When properly analyzed, many (probably most) claimed cases of positive selection will turn out to involve the fixation of slightly deleterious mutations by genetic drift in bottlenecked populations. Slightly deleterious variants are a transient feature of evolution in the long term, but they have substantially affected contemporary species, including our own.

  2. The Importance of ncRNAs as Epigenetic Mechanisms in Phenotypic Variation and Organic Evolution

    Directory of Open Access Journals (Sweden)

    Daniel Frías-Lasserre

    2017-12-01

    Full Text Available Neo-Darwinian explanations of organic evolution have settled on mutation as the principal factor in producing evolutionary novelty. Mechanistic characterizations have been also biased by the classic dogma of molecular biology, where only proteins regulate gene expression. This together with the rearrangement of genetic information, in terms of genes and chromosomes, was considered the cornerstone of evolution at the level of natural populations. This predominant view excluded both alternative explanations and phenomenologies that did not fit its paradigm. With the discovery of non-coding RNAs (ncRNAs and their role in the control of genetic expression, new mechanisms arose providing heuristic power to complementary explanations to evolutionary processes overwhelmed by mainstream genocentric views. Viruses, epimutation, paramutation, splicing, and RNA editing have been revealed as paramount functions in genetic variations, phenotypic plasticity, and diversity. This article discusses how current epigenetic advances on ncRNAs have changed the vision of the mechanisms that generate variation, how organism-environment interaction can no longer be underestimated as a driver of organic evolution, and how it is now part of the transgenerational inheritance and evolution of species.

  3. Punctuated Equilibrium in Statistical Models of Generalized Coevolutionary Resilience: How Sudden Ecosystem Transitions Can Entrain Both Phenotype Expression and Darwinian Selection

    Science.gov (United States)

    Wallace, Rodrick; Wallace, Deborah

    We argue that mesoscale ecosystem resilience shifts akin to sudden phase transitions in physical systems can entrain similarly punctuated events of gene expression on more rapid time scales, and, in part through such means, slower changes induced by selection pressure, triggering punctuated equilibrium Darwinian evolutionary transitions on geologic time scales. The approach reduces ecosystem, gene expression, and Darwinian genetic dynamics to a least common denominator of information sources interacting by crosstalk at markedly differing rates. Pettini's 'topological hypothesis', via a homology between information source uncertainty and free energy density, generates a regression-like class of statistical models of sudden coevolutionary phase transition based on the Rate Distortion and Shannon-McMillan Theorems of information theory which links all three levels. A mathematical treatment of Holling's extended keystone hypothesis regarding the particular role of mesoscale phenomena in entraining both slower and faster dynamical structures produces the result. A main theme is the necessity of a cognitive paradigm for gene expression, mirroring I. Cohen's cognitive approach to immune function. Invocation of the necessary conditions imposed by the asymptotic limit theorems of communication theory enables us to penetrate one layer more deeply before needing to impose an empirically-derived phenomenological system of 'Onsager relation' recursive coevolutionary stochastic differential equations. Extending the development to second order via a large deviations argument permits modeling the influence of human cultural structures on ecosystems as 'farming'.

  4. Genetic structure and evidence of putative Darwinian diversifying selection in the Potato yellow vein virus (PYVV

    Directory of Open Access Journals (Sweden)

    Giovanni Chaves-Bedoya

    2013-08-01

    Full Text Available The population structure and genetic variation of Potato yellow vein virus (PYVV were estimated by analysis of the nucleotide and deduced amino acid sequence of the coat protein of 69 isolates, reported in GenBank, from Solanum tuberosum (ST and Solanum phureja (SP hosts from different regions; predominantly Cundinamarca, Antioquia and Nariño, located in central and southwestern Colombia. Bioinformatics analysis revealed that despite the wide geographic distribution of different hosts and different collecting years, PYVV maintains a genetic similarity between 97.1 to 100.0%, indicating high spatial and temporal genetic stability of the major coat protein. No recombination events were found, but evidence was seen for the first time that this protein could be undergoing Darwinian diversifying selection

  5. Inference of Tumor Evolution during Chemotherapy by Computational Modeling and In Situ Analysis of Genetic and Phenotypic Cellular Diversity

    Directory of Open Access Journals (Sweden)

    Vanessa Almendro

    2014-02-01

    Full Text Available Cancer therapy exerts a strong selection pressure that shapes tumor evolution, yet our knowledge of how tumors change during treatment is limited. Here, we report the analysis of cellular heterogeneity for genetic and phenotypic features and their spatial distribution in breast tumors pre- and post-neoadjuvant chemotherapy. We found that intratumor genetic diversity was tumor-subtype specific, and it did not change during treatment in tumors with partial or no response. However, lower pretreatment genetic diversity was significantly associated with pathologic complete response. In contrast, phenotypic diversity was different between pre- and posttreatment samples. We also observed significant changes in the spatial distribution of cells with distinct genetic and phenotypic features. We used these experimental data to develop a stochastic computational model to infer tumor growth patterns and evolutionary dynamics. Our results highlight the importance of integrated analysis of genotypes and phenotypes of single cells in intact tissues to predict tumor evolution.

  6. Inference of tumor evolution during chemotherapy by computational modeling and in situ analysis of genetic and phenotypic cellular diversity

    International Nuclear Information System (INIS)

    Almendro, Vanessa; Cheng, Yu-Kang; Randles, Amanda; Itzkovitz, Shalev; Marusyk, Andriy; Ametller, Elisabet; Gonzalez-Farre, Xavier; Muñoz, Montse; Russnes, Hege G.; Helland, Åslaug; Rye, Inga H.; Borresen-Dale, Anne-Lise; Maruyama, Reo; Van Oudenaarden, Alexander; Dowsett, Mitchell; Jones, Robin L.; Reis-Filho, Jorge; Gascon, Pere; Gönen, Mithat; Michor, Franziska; Polyak, Kornelia

    2014-01-01

    Cancer therapy exerts a strong selection pressure that shapes tumor evolution, yet our knowledge of how tumors change during treatment is limited. Here, we report the analysis of cellular heterogeneity for genetic and phenotypic features and their spatial distribution in breast tumors pre- and post-neoadjuvant chemotherapy. We found that intratumor genetic diversity was tumor-subtype specific, and it did not change during treatment in tumors with partial or no response. However, lower pretreatment genetic diversity was significantly associated with pathologic complete response. In contrast, phenotypic diversity was different between pre- and post-treatment samples. We also observed significant changes in the spatial distribution of cells with distinct genetic and phenotypic features. We used these experimental data to develop a stochastic computational model to infer tumor growth patterns and evolutionary dynamics. Our results highlight the importance of integrated analysis of genotypes and phenotypes of single cells in intact tissues to predict tumor evolution

  7. Towards Co-evolution of Membranes and Metabolism

    Science.gov (United States)

    Wei, Chenyu; Wilson, Michael A.; Pohorille, Andrew

    2014-01-01

    Conceptually, the most robust way to explain how primitive cell-like structures acquired and increased their capabilities is on the basis of Darwinian evolution. A population of protocells containing material that produced more environmentally fit progeny would increase in time at the expense of other protocells. In this scenario, protocellular boundaries were inextricably connected to the metabolism they encapsulated: to be inheritable, early metabolism must have led to an increased rate of growth and division of vesicles and, similarly, transport through vesicle boundaries must have supported the evolution of metabolism. Everything that could not be delivered from the environment had to be produced and retained inside protocells. Despite their importance to the understanding of the origin of life, only a few cases of coupling between metabolism and membrane-related processes have been identified so far. For example, reactions inside fatty-acid vesicles have been linked to their competitive growth and division, and mechanisms by which membrane permeability might have coupled to information polymers have been proposed and explained. Most recently, it has been shown that a dipeptide inside fatty-acid vesicles catalyzes the formation of another dipeptide that binds to vesicle walls and, by doing so, promotes their growth at the expense of other vesicles, thus demonstrating evolutionary advantage of small, membrane-bound peptides. It has been shown that the appearance of phospholipids imparted selective advantage to protocells bound by phospholipid-containing membranes, eventually driving fatty-acid vesicles to extinction. Phospholipid membranes, however, are nearly impermeable to charged species. Yet, the ability to transport ions across membranes was vital for regulating cellular volume, pH homeostasis, generating energy and sensing the environment. To account for this, evolutionary scenarios for the emergence of simple ion channels, protein structures surrounding

  8. Passive Noise Filtering by Cellular Compartmentalization.

    Science.gov (United States)

    Stoeger, Thomas; Battich, Nico; Pelkmans, Lucas

    2016-03-10

    Chemical reactions contain an inherent element of randomness, which presents itself as noise that interferes with cellular processes and communication. Here we discuss the ability of the spatial partitioning of molecular systems to filter and, thus, remove noise, while preserving regulated and predictable differences between single living cells. In contrast to active noise filtering by network motifs, cellular compartmentalization is highly effective and easily scales to numerous systems without requiring a substantial usage of cellular energy. We will use passive noise filtering by the eukaryotic cell nucleus as an example of how this increases predictability of transcriptional output, with possible implications for the evolution of complex multicellularity. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. "The Two Brothers": Reconciling Perceptual-Cognitive and Statistical Models of Musical Evolution.

    Science.gov (United States)

    Jan, Steven

    2018-01-01

    While the "units, events and dynamics" of memetic evolution have been abstractly theorized (Lynch, 1998), they have not been applied systematically to real corpora in music. Some researchers, convinced of the validity of cultural evolution in more than the metaphorical sense adopted by much musicology, but perhaps skeptical of some or all of the claims of memetics, have attempted statistically based corpus-analysis techniques of music drawn from molecular biology, and these have offered strong evidence in favor of system-level change over time (Savage, 2017). This article argues that such statistical approaches, while illuminating, ignore the psychological realities of music-information grouping, the transmission of such groups with varying degrees of fidelity, their selection according to relative perceptual-cognitive salience, and the power of this Darwinian process to drive the systemic changes (such as the development over time of systems of tonal organization in music) that statistical methodologies measure. It asserts that a synthesis between such statistical approaches to the study of music-cultural change and the theory of memetics as applied to music (Jan, 2007), in particular the latter's perceptual-cognitive elements, would harness the strengths of each approach and deepen understanding of cultural evolution in music.

  10. The role of rules in the evolution of the market system: Hayek’s concept of evolutionary epistemology

    Directory of Open Access Journals (Sweden)

    Krstić Miloš

    2012-01-01

    Full Text Available Starting from the concept of the Darwinian paradigm that, by using Darwin’s principles of variation, selection, and retention, all domains from biology to economic systems can be explained, the advocates of modern evolutionary epistemology have analyzed the role of thoughtful institutional design in the process of cultural evolution. In light of the issue of how human intention and evolutionary forces interact in socioeconomic processes, this paper examines the views of F. A. Hayek, the most famous follower of evolutionary epistemology, on the evolution of the market economy system. In this paper special attention will be devoted to Hayek’s concept of rational liberalism and his evolutionary epistemology. [Ministarstva nauke Republike Srbije, br. 179066: Improving the Competitiveness of the Public and Private Sectors by Networking Competences in the European Integration Process of Serbia

  11. Evolution before genes

    Directory of Open Access Journals (Sweden)

    Vasas Vera

    2012-01-01

    Full Text Available Abstract Background Our current understanding of evolution is so tightly linked to template-dependent replication of DNA and RNA molecules that the old idea from Oparin of a self-reproducing 'garbage bag' ('coacervate' of chemicals that predated fully-fledged cell-like entities seems to be farfetched to most scientists today. However, this is exactly the kind of scheme we propose for how Darwinian evolution could have occurred prior to template replication. Results We cannot confirm previous claims that autocatalytic sets of organic polymer molecules could undergo evolution in any interesting sense by themselves. While we and others have previously imagined inhibition would result in selectability, we found that it produced multiple attractors in an autocatalytic set that cannot be selected for. Instead, we discovered that if general conditions are satisfied, the accumulation of adaptations in chemical reaction networks can occur. These conditions are the existence of rare reactions producing viable cores (analogous to a genotype, that sustains a molecular periphery (analogous to a phenotype. Conclusions We conclude that only when a chemical reaction network consists of many such viable cores, can it be evolvable. When many cores are enclosed in a compartment there is competition between cores within the same compartment, and when there are many compartments, there is between-compartment competition due to the phenotypic effects of cores and their periphery at the compartment level. Acquisition of cores by rare chemical events, and loss of cores at division, allows macromutation, limited heredity and selectability, thus explaining how a poor man's natural selection could have operated prior to genetic templates. This is the only demonstration to date of a mechanism by which pre-template accumulation of adaptation could occur. Reviewers This article was reviewed by William Martin and Eugene Koonin.

  12. Algorithm for cellular reprogramming.

    Science.gov (United States)

    Ronquist, Scott; Patterson, Geoff; Muir, Lindsey A; Lindsly, Stephen; Chen, Haiming; Brown, Markus; Wicha, Max S; Bloch, Anthony; Brockett, Roger; Rajapakse, Indika

    2017-11-07

    The day we understand the time evolution of subcellular events at a level of detail comparable to physical systems governed by Newton's laws of motion seems far away. Even so, quantitative approaches to cellular dynamics add to our understanding of cell biology. With data-guided frameworks we can develop better predictions about, and methods for, control over specific biological processes and system-wide cell behavior. Here we describe an approach for optimizing the use of transcription factors (TFs) in cellular reprogramming, based on a device commonly used in optimal control. We construct an approximate model for the natural evolution of a cell-cycle-synchronized population of human fibroblasts, based on data obtained by sampling the expression of 22,083 genes at several time points during the cell cycle. To arrive at a model of moderate complexity, we cluster gene expression based on division of the genome into topologically associating domains (TADs) and then model the dynamics of TAD expression levels. Based on this dynamical model and additional data, such as known TF binding sites and activity, we develop a methodology for identifying the top TF candidates for a specific cellular reprogramming task. Our data-guided methodology identifies a number of TFs previously validated for reprogramming and/or natural differentiation and predicts some potentially useful combinations of TFs. Our findings highlight the immense potential of dynamical models, mathematics, and data-guided methodologies for improving strategies for control over biological processes. Copyright © 2017 the Author(s). Published by PNAS.

  13. Extended Cellular Automata Models of Particles and Space-Time

    Science.gov (United States)

    Beedle, Michael

    2005-04-01

    Models of particles and space-time are explored through simulations and theoretical models that use Extended Cellular Automata models. The expanded Cellular Automata Models consist go beyond simple scalar binary cell-fields, into discrete multi-level group representations like S0(2), SU(2), SU(3), SPIN(3,1). The propagation and evolution of these expanded cellular automatas are then compared to quantum field theories based on the "harmonic paradigm" i.e. built by an infinite number of harmonic oscillators, and with gravitational models.

  14. The teaching of evolution in Portugal in the early 20th century through the programs and textbooks of Zoology

    Directory of Open Access Journals (Sweden)

    Bento CAVADAS

    2011-11-01

    Full Text Available The teaching of evolution in the Portuguese secondary schools is not yet fully understood. This research aimed to contribute to this clarification, in the framework of the history of the curriculum and the biology subject, by showing the expressions of the evolutionism teaching in the first three decades of the twentieth century. To this end we analyzed the programs of Zoology of 1905 and 1919, as well as two textbooks, entitled «Lições de Zoologia» and written by Bernardo Aires in accordance with these programs. This analysis showed that the study of evolution, eliminated from the program in 1905, was again recognized in the program in 1919. In textbooks, the exposure of evolution focused on the subject of evolution, in the grounds of competition and natural selection, adaptation, the biogenetic law and the essential differences between Lamarckism and Darwinism. The comparative study of these textbooks showed that the text which addresses the evolution is essentially Darwinian. However, neoLamarckians sections have been identified that show the influence of the «eclipse of Darwinism» on the teaching of evolutionism.

  15. Terminal addition in a cellular world.

    Science.gov (United States)

    Torday, J S; Miller, William B

    2018-07-01

    Recent advances in our understanding of evolutionary development permit a reframed appraisal of Terminal Addition as a continuous historical process of cellular-environmental complementarity. Within this frame of reference, evolutionary terminal additions can be identified as environmental induction of episodic adjustments to cell-cell signaling patterns that yield the cellular-molecular pathways that lead to differing developmental forms. Phenotypes derive, thereby, through cellular mutualistic/competitive niche constructions in reciprocating responsiveness to environmental stresses and epigenetic impacts. In such terms, Terminal Addition flows according to a logic of cellular needs confronting environmental challenges over space-time. A reconciliation of evolutionary development and Terminal Addition can be achieved through a combined focus on cell-cell signaling, molecular phylogenies and a broader understanding of epigenetic phenomena among eukaryotic organisms. When understood in this manner, Terminal Addition has an important role in evolutionary development, and chronic disease might be considered as a form of 'reverse evolution' of the self-same processes. Copyright © 2017. Published by Elsevier Ltd.

  16. Dirac Mass Dynamics in Multidimensional Nonlocal Parabolic Equations

    KAUST Repository

    Lorz, Alexander; Mirrahimi, Sepideh; Perthame, Benoî t

    2011-01-01

    simulations show that the trajectories can exhibit unexpected dynamics well explained by this equation. Our motivation comes from population adaptive evolution a branch of mathematical ecology which models Darwinian evolution. © Taylor & Francis Group, LLC.

  17. Brewing controversies: Darwinian perspective on the adaptive and maladaptive effects of caffeine and ethanol as dietary autonomic modulators.

    Science.gov (United States)

    Yun, Anthony J; Doux, John D; Daniel, Stephanie M

    2007-01-01

    Ethanol and caffeine are two of the oldest human drugs. Their pervasive integration into the modern human diet may reflect behavioral attempts to correct maladaptations induced by evolutionary displacement of the autonomic system. The dietary adoption of caffeine may parallel the emergence of cognition as an independent basis of competition. Enhancement of the cognitive ability to gather and process information likely evolved as a valuable adjunct to physical behavior in prehistoric fight-or-flight encounters. Caffeine effectively exploits this pre-existing association between adrenergic activity and cognitive readiness, leading to its use in the modern environment where success in competition increasingly depends on cognitive, rather than physical, prowess. Ethanol may have emerged as a dietary means to buffer the maladaptive chronic sympathetic activation and fear response associated with stressful lifestyles and the social phobias associated with the dissolution of kin networks. We explore the health implications of ethanol and caffeine use, with particular attention to their acute and chronic effects on the autonomic axis. The putative protective effects of ethanol in surviving major trauma or reducing inflammation and heart disease may relate to tempering the behavioral and cardiovascular consequences of catastrophic or chronic sympathetic activation. Acute or chronic abuse of ethanol manifests paradoxical pro-adrenergic effects such as tremors and insomnia that may partly represent compensatory responses. Compensatory remodeling may also explain why confirmation of detrimental effects related to caffeine-induced sympathetic activation has proven elusive; indeed, paradoxical pro-vagal benefits may eventually be recognized. Ethanol and caffeine are potential agents that may beneficially expand the dynamic range of the autonomic system. In an environment where the Darwinian value of knowledge has increasingly supplanted that of physical traits, the consumption

  18. The Fact of Evolution: Implications for Science Education

    Science.gov (United States)

    Hofmann, James R.; Weber, Bruce H.

    Creationists who object to evolution in the science curriculum of public schools often cite Jonathan Well's book Icons of Evolution in their support (Wells2000). In the third chapter of his book Wells claims that neither paleontological nor molecular evidence supports the thesis that the history of life is an evolutionary process of descent from preexisting ancestors. We argue that Wells inappropriately relies upon ambiguities inherent in the term `Darwinian' and the phrase `Darwin'stheory'. Furthermore, he does not accurately distinguish between the overwhelming evidence that supports the thesis of common descent and controversies that pertain to causal mechanisms such as natural selection. We also argue that Wells' attempts to undermine the evidence in support of common descent are flawed and his characterization of the relevant data is misleading. In particular, his assessment of the `Cambrian explosion' does not do justice to the fossil record. Nor do his selective references to debate about molecular and paleontological phylogenies constitute a case against common descent. We conclude that the fossil and molecular evidence is more than sufficient to warrant science educators to present common descent as a well-established scientific fact. We also argue that diagrams depicting the `tree of life' can be pedagogically useful as simplified representations of the history of life.

  19. Evolution of Cellular Inclusions in Bietti's Crystalline Dystrophy.

    Science.gov (United States)

    Furusato, Emiko; Cameron, J Douglas; Chan, Chi-Chao

    2010-03-09

    Bietti's crystalline dystrophy (BCD) consists of small, yellow-white, glistening intraretinal crystals in the posterior pole, tapetoretinal degeneration with atrophy of the retinal pigment epithelium (RPE) and "sclerosis" of the choroid; in addition, sparking yellow crystals in the superficial marginal cornea are also found in many patients. BCD is inherited as an autosomal-recessive trait (4q35-tel) and usually has its onset in the third decade of life. This review focuses on the ultrastructure of cellular crystals and lipid inclusions of BCD.

  20. “The Two Brothers”: Reconciling Perceptual-Cognitive and Statistical Models of Musical Evolution

    Science.gov (United States)

    Jan, Steven

    2018-01-01

    While the “units, events and dynamics” of memetic evolution have been abstractly theorized (Lynch, 1998), they have not been applied systematically to real corpora in music. Some researchers, convinced of the validity of cultural evolution in more than the metaphorical sense adopted by much musicology, but perhaps skeptical of some or all of the claims of memetics, have attempted statistically based corpus-analysis techniques of music drawn from molecular biology, and these have offered strong evidence in favor of system-level change over time (Savage, 2017). This article argues that such statistical approaches, while illuminating, ignore the psychological realities of music-information grouping, the transmission of such groups with varying degrees of fidelity, their selection according to relative perceptual-cognitive salience, and the power of this Darwinian process to drive the systemic changes (such as the development over time of systems of tonal organization in music) that statistical methodologies measure. It asserts that a synthesis between such statistical approaches to the study of music-cultural change and the theory of memetics as applied to music (Jan, 2007), in particular the latter's perceptual-cognitive elements, would harness the strengths of each approach and deepen understanding of cultural evolution in music. PMID:29670551

  1. “The Two Brothers”: Reconciling Perceptual-Cognitive and Statistical Models of Musical Evolution

    Directory of Open Access Journals (Sweden)

    Steven Jan

    2018-04-01

    Full Text Available While the “units, events and dynamics” of memetic evolution have been abstractly theorized (Lynch, 1998, they have not been applied systematically to real corpora in music. Some researchers, convinced of the validity of cultural evolution in more than the metaphorical sense adopted by much musicology, but perhaps skeptical of some or all of the claims of memetics, have attempted statistically based corpus-analysis techniques of music drawn from molecular biology, and these have offered strong evidence in favor of system-level change over time (Savage, 2017. This article argues that such statistical approaches, while illuminating, ignore the psychological realities of music-information grouping, the transmission of such groups with varying degrees of fidelity, their selection according to relative perceptual-cognitive salience, and the power of this Darwinian process to drive the systemic changes (such as the development over time of systems of tonal organization in music that statistical methodologies measure. It asserts that a synthesis between such statistical approaches to the study of music-cultural change and the theory of memetics as applied to music (Jan, 2007, in particular the latter's perceptual-cognitive elements, would harness the strengths of each approach and deepen understanding of cultural evolution in music.

  2. Cui bono? A review of breaking the spell: religion as a natural phenomenon by Daniel C. Dennett.

    Science.gov (United States)

    Rachlin, Howard

    2007-01-01

    The three requirements for a Darwinian evolutionary process are replication, variation and selection. Dennett (2006) discusses various theories of how these three processes, especially selection, may have operated in the evolution of religion. He believes that the origins of religion, like the origins of language and music, may be approached scientifically. He hopes that such investigations will open a dialog between science and religion leading to moderation of current religious extremism. One problem with Dennett's program, illustrating the difficulty of breaking away from creationist thinking, is Dennett's own failure to consider how Darwinian methods may be used to study evolution of behavioral patterns over the lifetime of individual organisms.

  3. Cellular potts models multiscale extensions and biological applications

    CERN Document Server

    Scianna, Marco

    2013-01-01

    A flexible, cell-level, and lattice-based technique, the cellular Potts model accurately describes the phenomenological mechanisms involved in many biological processes. Cellular Potts Models: Multiscale Extensions and Biological Applications gives an interdisciplinary, accessible treatment of these models, from the original methodologies to the latest developments. The book first explains the biophysical bases, main merits, and limitations of the cellular Potts model. It then proposes several innovative extensions, focusing on ways to integrate and interface the basic cellular Potts model at the mesoscopic scale with approaches that accurately model microscopic dynamics. These extensions are designed to create a nested and hybrid environment, where the evolution of a biological system is realistically driven by the constant interplay and flux of information between the different levels of description. Through several biological examples, the authors demonstrate a qualitative and quantitative agreement with t...

  4. Directional Darwinian Selection in proteins.

    Science.gov (United States)

    McClellan, David A

    2013-01-01

    Molecular evolution is a very active field of research, with several complementary approaches, including dN/dS, HON90, MM01, and others. Each has documented strengths and weaknesses, and no one approach provides a clear picture of how natural selection works at the molecular level. The purpose of this work is to present a simple new method that uses quantitative amino acid properties to identify and characterize directional selection in proteins. Inferred amino acid replacements are viewed through the prism of a single physicochemical property to determine the amount and direction of change caused by each replacement. This allows the calculation of the probability that the mean change in the single property associated with the amino acid replacements is equal to zero (H0: μ = 0; i.e., no net change) using a simple two-tailed t-test. Example data from calanoid and cyclopoid copepod cytochrome oxidase subunit I sequence pairs are presented to demonstrate how directional selection may be linked to major shifts in adaptive zones, and that convergent evolution at the whole organism level may be the result of convergent protein adaptations. Rather than replace previous methods, this new method further complements existing methods to provide a holistic glimpse of how natural selection shapes protein structure and function over evolutionary time.

  5. Explanation of climate and human impacts on sediment discharge change in Darwinian hydrology: Derivation of a differential equation

    Science.gov (United States)

    Zhang, Jianjun; Gao, Guangyao; Fu, Bojie; Zhang, Lu

    2018-04-01

    The assessment for impacts of climate variability and human activities on suspended sediment yield (SSY) change has long been a question of great interest. However, the sediment generation processes are sophisticated with high nonlinearity and great uncertainty, which give rise to extreme complexity for SSY change assessment in Newtonian approach. Consequently, few approaches can be simply but widely applied to decompose impacts of climatic variability and human activities on SSY change. Thus, it is an urgent need to develop advanced methods that are simple and robust. Since that the Newtonian approach is hardly achievable due to limitation of either observations or knowledge of mechanisms, there have been repeated calls to capture the hydrologic system in Darwinian approach for hydrological change prediction or explanation. As streamflow is the carrier of suspended sediment, SSY change are thus documented in changes of sediment concentrated flow and suspended sediment concentration - water discharge (C-Q) relationships. By deduced corollaries, a differential equation of sediment discharge change was derived to explicitly decompose impacts of climate variability and human activities in Darwinian hydrology. Besides, a new form of sediment rating curves was proposed and curved as C-Q relationships and probability distribution of sediment concentrated flow. River sediment flux can be revealed by this representation, which simply elucidates mechanism of SSY generation covering a range of time scales from finer than rainfall-event to long term. By the new sediment rating curves, the differential equation was partly solved using a segmentation algorithm proposed and validated in this paper, and then was submitted to water balance framework expressed by Budyko-type equation. Thus, for catchment management, hydrologists can obtain explicit explanation of how climate variation and human activities propagate through landscape and result in sediment discharge change. The

  6. The evolution of episodic memory

    Science.gov (United States)

    Allen, Timothy A.; Fortin, Norbert J.

    2013-01-01

    One prominent view holds that episodic memory emerged recently in humans and lacks a “(neo)Darwinian evolution” [Tulving E (2002) Annu Rev Psychol 53:1–25]. Here, we review evidence supporting the alternative perspective that episodic memory has a long evolutionary history. We show that fundamental features of episodic memory capacity are present in mammals and birds and that the major brain regions responsible for episodic memory in humans have anatomical and functional homologs in other species. We propose that episodic memory capacity depends on a fundamental neural circuit that is similar across mammalian and avian species, suggesting that protoepisodic memory systems exist across amniotes and, possibly, all vertebrates. The implication is that episodic memory in diverse species may primarily be due to a shared underlying neural ancestry, rather than the result of evolutionary convergence. We also discuss potential advantages that episodic memory may offer, as well as species-specific divergences that have developed on top of the fundamental episodic memory architecture. We conclude by identifying possible time points for the emergence of episodic memory in evolution, to help guide further research in this area. PMID:23754432

  7. Selection within organisms in the nineteenth century: Wilhelm Roux's complex legacy.

    Science.gov (United States)

    Heams, Thomas

    2012-09-01

    Selectionism, or the extension of darwinian chance/selection dynamics beyond the individual level, has a long history in biological thought. It has generated important theories in immunology or neurology, and turns out to be a convincing framework to account for the intrinsic stochastic nature of core events in cellular biology. When looking back at the intellectual origins of selectionism, the essay by the German embryologist Wilhelm Roux, Der Kampf der Theile im Organismus (The Struggle of the Parts in the Organism - 1881) might be one, if not the earliest reference after the darwinian revolution. It describes the individual as a multilevel structure, where each level results from a 'darwinian' struggle of its parts (molecules, cells, tissues, organs). But Roux's theory, far from being a simple extension of natural selection, has complex and even conflictual relationships with darwinism. This essay is worth rediscovering as a subtle historical testimony of the evolutionary and developmental life sciences debates of its time. Moreover, some of its theses may also enrich some current debates among evolutionary biologists over levels of selection, and among cellular and molecular biologists over the status of determinism in biology today. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Engineering the functional fitness of transglycosidases and ...

    African Journals Online (AJOL)

    The artificial implementation of the Darwinian theory of evolution to create new variants of functional proteins, a process referred to as directed evolution, has acquired many applications in biochemical engineering. Directed evolution is a handy tool in the nascent science of glycobiology, where it is used in the conversion of ...

  9. Sexual selection: Another Darwinian process.

    Science.gov (United States)

    Gayon, Jean

    2010-02-01

    the Darwin-Wallace controversy was that most Darwinian biologists avoided the subject of sexual selection until at least the 1950s, Ronald Fisher being a major exception. This controversy still deserves attention from modern evolutionary biologists, because the modern approach inherits from both Darwin and Wallace. The modern approach tends to present sexual selection as a special aspect of the theory of natural selection, although it also recognizes the big difficulties resulting from the inevitable interaction between these two natural processes of selection. And contra Wallace, it considers mate choice as a major process that deserves a proper evolutionary treatment. The paper's conclusion explains why sexual selection can be taken as a test case for a proper assessment of "Darwinism" as a scientific tradition. Darwin's and Wallace's attitudes towards sexual selection reveal two different interpretations of the principle of natural selection: Wallace's had an environmentalist conception of natural selection, whereas Darwin was primarily sensitive to the element of competition involved in the intimate mechanism of any natural process of selection. Sexual selection, which can lack adaptive significance, reveals this exemplarily. 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  10. Paleontology and Darwin's Theory of Evolution: The Subversive Role of Statistics at the End of the 19th Century.

    Science.gov (United States)

    Tamborini, Marco

    2015-11-01

    This paper examines the subversive role of statistics paleontology at the end of the 19th and the beginning of the 20th centuries. In particular, I will focus on German paleontology and its relationship with statistics. I argue that in paleontology, the quantitative method was questioned and strongly limited by the first decade of the 20th century because, as its opponents noted, when the fossil record is treated statistically, it was found to generate results openly in conflict with the Darwinian theory of evolution. Essentially, statistics questions the gradual mode of evolution and the role of natural selection. The main objections to statistics were addressed during the meetings at the Kaiserlich-Königliche Geologische Reichsanstalt in Vienna in the 1880s. After having introduced the statistical treatment of the fossil record, I will use the works of Charles Léo Lesquereux (1806-1889), Joachim Barrande (1799-1833), and Henry Shaler Williams (1847-1918) to compare the objections raised in Vienna with how the statistical treatment of the data worked in practice. Furthermore, I will discuss the criticisms of Melchior Neumayr (1845-1890), one of the leading German opponents of statistical paleontology, to show why, and to what extent, statistics were questioned in Vienna. The final part of this paper considers what paleontologists can derive from a statistical notion of data: the necessity of opening a discussion about the completeness and nature of the paleontological data. The Vienna discussion about which method paleontologists should follow offers an interesting case study in order to understand the epistemic tensions within paleontology surrounding Darwin's theory as well as the variety of non-Darwinian alternatives that emerged from the statistical treatment of the fossil record at the end of the 19th century.

  11. NATO Advanced Study Institute on Evolution from Cellular to Social Scales

    CERN Document Server

    Skjeltorp, Arne T

    2008-01-01

    Evolution is a critical challenge for many areas of science, technology and development of society. The book reviews general evolutionary facts such as origin of life and evolution of the genome and clues to evolution through simple systems. Emerging areas of science such as "systems biology" and "bio-complexity" are founded on the idea that phenomena need to be understood in the context of highly interactive processes operating at different levels and on different scales. This is where physics meets complexity in nature, and where we must begin to learn about complexity if we are to understand it. Similarly, there is an increasingly urgent need to understand and predict the evolutionary behavior of highly interacting man-made systems, in areas such as communications and transport, which permeate the modern world. The same applies to the evolution of human networks such as social, political and financial systems, where technology has tended to vastly increase both the complexity and speed of interaction, whic...

  12. Evolution and the complexity of bacteriophages.

    Science.gov (United States)

    Serwer, Philip

    2007-03-13

    The genomes of both long-genome (> 200 Kb) bacteriophages and long-genome eukaryotic viruses have cellular gene homologs whose selective advantage is not explained. These homologs add genomic and possibly biochemical complexity. Understanding their significance requires a definition of complexity that is more biochemically oriented than past empirically based definitions. Initially, I propose two biochemistry-oriented definitions of complexity: either decreased randomness or increased encoded information that does not serve immediate needs. Then, I make the assumption that these two definitions are equivalent. This assumption and recent data lead to the following four-part hypothesis that explains the presence of cellular gene homologs in long bacteriophage genomes and also provides a pathway for complexity increases in prokaryotic cells: (1) Prokaryotes underwent evolutionary increases in biochemical complexity after the eukaryote/prokaryote splits. (2) Some of the complexity increases occurred via multi-step, weak selection that was both protected from strong selection and accelerated by embedding evolving cellular genes in the genomes of bacteriophages and, presumably, also archaeal viruses (first tier selection). (3) The mechanisms for retaining cellular genes in viral genomes evolved under additional, longer-term selection that was stronger (second tier selection). (4) The second tier selection was based on increased access by prokaryotic cells to improved biochemical systems. This access was achieved when DNA transfer moved to prokaryotic cells both the more evolved genes and their more competitive and complex biochemical systems. I propose testing this hypothesis by controlled evolution in microbial communities to (1) determine the effects of deleting individual cellular gene homologs on the growth and evolution of long genome bacteriophages and hosts, (2) find the environmental conditions that select for the presence of cellular gene homologs, (3) determine

  13. Evolution and the complexity of bacteriophages

    Directory of Open Access Journals (Sweden)

    Serwer Philip

    2007-03-01

    Full Text Available Abstract Background The genomes of both long-genome (> 200 Kb bacteriophages and long-genome eukaryotic viruses have cellular gene homologs whose selective advantage is not explained. These homologs add genomic and possibly biochemical complexity. Understanding their significance requires a definition of complexity that is more biochemically oriented than past empirically based definitions. Hypothesis Initially, I propose two biochemistry-oriented definitions of complexity: either decreased randomness or increased encoded information that does not serve immediate needs. Then, I make the assumption that these two definitions are equivalent. This assumption and recent data lead to the following four-part hypothesis that explains the presence of cellular gene homologs in long bacteriophage genomes and also provides a pathway for complexity increases in prokaryotic cells: (1 Prokaryotes underwent evolutionary increases in biochemical complexity after the eukaryote/prokaryote splits. (2 Some of the complexity increases occurred via multi-step, weak selection that was both protected from strong selection and accelerated by embedding evolving cellular genes in the genomes of bacteriophages and, presumably, also archaeal viruses (first tier selection. (3 The mechanisms for retaining cellular genes in viral genomes evolved under additional, longer-term selection that was stronger (second tier selection. (4 The second tier selection was based on increased access by prokaryotic cells to improved biochemical systems. This access was achieved when DNA transfer moved to prokaryotic cells both the more evolved genes and their more competitive and complex biochemical systems. Testing the hypothesis I propose testing this hypothesis by controlled evolution in microbial communities to (1 determine the effects of deleting individual cellular gene homologs on the growth and evolution of long genome bacteriophages and hosts, (2 find the environmental conditions that

  14. Journal of Genetics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Keywords. cytosine methylation; DNA methylation mechanisms; DNA demethylation mechanisms; Darwinian-cum-Lamarckian evolution; epialleles; epigenetic modifications; genetic recombination; heritable induced defence; mutational hotspots; transgenerational inheritance.

  15. A virocentric perspective on the evolution of life

    Science.gov (United States)

    Koonin, Eugene V.; Dolja, Valerian V.

    2015-01-01

    Viruses and/or virus-like selfish elements are associated with all cellular life forms and are the most abundant biological entities on Earth, with the number of virus particles in many environments exceeding the number of cells by one to two orders of magnitude. The genetic diversity of viruses is commensurately enormous and might substantially exceed the diversity of cellular organisms. Unlike cellular organisms with their uniform replication-expression scheme, viruses possess either RNA or DNA genomes and exploit all conceivable replication-expression strategies. Although viruses extensively exchange genes with their hosts, there exists a set of viral hallmark genes that are shared by extremely diverse groups of viruses to the exclusion of cellular life forms. Coevolution of viruses and host defense systems is a key aspect in the evolution of both viruses and cells, and viral genes are often recruited for cellular functions. Together with the fundamental inevitability of the emergence of genomic parasites in any evolving replicator system, these multiple lines of evidence reveal the central role of viruses in the entire evolution of life. PMID:23850169

  16. Evolution to 3G Mobile Communication - Second Generation ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 9. Evolution to 3G Mobile Communication - Second Generation Cellular Systems. R Ramachandran. General Article Volume 8 Issue 9 September 2003 pp 60-72 ... Keywords. Wireless communication; cellular networks; GSM; CdmaOne; TDMA ...

  17. Applying ecological and evolutionary theory to cancer: a long and winding road.

    Science.gov (United States)

    Thomas, Frédéric; Fisher, Daniel; Fort, Philippe; Marie, Jean-Pierre; Daoust, Simon; Roche, Benjamin; Grunau, Christoph; Cosseau, Céline; Mitta, Guillaume; Baghdiguian, Stephen; Rousset, François; Lassus, Patrice; Assenat, Eric; Grégoire, Damien; Missé, Dorothée; Lorz, Alexander; Billy, Frédérique; Vainchenker, William; Delhommeau, François; Koscielny, Serge; Itzykson, Raphael; Tang, Ruoping; Fava, Fanny; Ballesta, Annabelle; Lepoutre, Thomas; Krasinska, Liliana; Dulic, Vjekoslav; Raynaud, Peggy; Blache, Philippe; Quittau-Prevostel, Corinne; Vignal, Emmanuel; Trauchessec, Hélène; Perthame, Benoit; Clairambault, Jean; Volpert, Vitali; Solary, Eric; Hibner, Urszula; Hochberg, Michael E

    2013-01-01

    Since the mid 1970s, cancer has been described as a process of Darwinian evolution, with somatic cellular selection and evolution being the fundamental processes leading to malignancy and its many manifestations (neoangiogenesis, evasion of the immune system, metastasis, and resistance to therapies). Historically, little attention has been placed on applications of evolutionary biology to understanding and controlling neoplastic progression and to prevent therapeutic failures. This is now beginning to change, and there is a growing international interest in the interface between cancer and evolutionary biology. The objective of this introduction is first to describe the basic ideas and concepts linking evolutionary biology to cancer. We then present four major fronts where the evolutionary perspective is most developed, namely laboratory and clinical models, mathematical models, databases, and techniques and assays. Finally, we discuss several of the most promising challenges and future prospects in this interdisciplinary research direction in the war against cancer.

  18. The Reciprocal Links between Evolutionary-Ecological Sciences and Environmental Ethics.

    Science.gov (United States)

    Rozzi, Ricardo

    1999-01-01

    Illustrates the reciprocal relationships between the sciences and environmental ethics by examining the Darwinian theory of evolution and discussing its implications for ecologists and ethicists. (CCM)

  19. Perturbations of dynamics of homogeneous two-dimensional cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Makowiec, D [Gdansk Univ. (Poland)

    1993-04-01

    The probabilistic approach provides a useful tool for understanding the nature of dynamics of cellular automata. It allows not only clarification of different results of the evolution but also gives explanation to the physical meaning of the rules. (author). 11 refs, 4 figs.

  20. Transmission of clonal hepatitis C virus genomes reveals the dominant but transitory role of CD8¿ T cells in early viral evolution

    DEFF Research Database (Denmark)

    Callendret, Benoît; Bukh, Jens; Eccleston, Heather B

    2011-01-01

    occurred slowly over several years of chronic infection. Together these observations indicate that during acute hepatitis C, virus evolution was driven primarily by positive selection pressure exerted by CD8(+) T cells. This influence of immune pressure on viral evolution appears to subside as chronic......The RNA genome of the hepatitis C virus (HCV) diversifies rapidly during the acute phase of infection, but the selective forces that drive this process remain poorly defined. Here we examined whether Darwinian selection pressure imposed by CD8(+) T cells is a dominant force driving early amino acid...... replacement in HCV viral populations. This question was addressed in two chimpanzees followed for 8 to 10 years after infection with a well-defined inoculum composed of a clonal genotype 1a (isolate H77C) HCV genome. Detailed characterization of CD8(+) T cell responses combined with sequencing of recovered...

  1. The naturalist view of Universal Darwinism: an application to the evolutionary theory of the firm

    NARCIS (Netherlands)

    Stoelhorst, J.W.; Finch, J.; Orillard, M.

    2005-01-01

    The purpose of this paper is to contribute to recent efforts to ground evolutionary theory in economics in the principles of Universal Darwinism. The paper contrasts two views of evolution, based on the Ultra-Darwinian and Naturalist theory of biological evolution, both of which are consistent with

  2. Lempel-Ziv complexity analysis of one dimensional cellular automata.

    Science.gov (United States)

    Estevez-Rams, E; Lora-Serrano, R; Nunes, C A J; Aragón-Fernández, B

    2015-12-01

    Lempel-Ziv complexity measure has been used to estimate the entropy density of a string. It is defined as the number of factors in a production factorization of a string. In this contribution, we show that its use can be extended, by using the normalized information distance, to study the spatiotemporal evolution of random initial configurations under cellular automata rules. In particular, the transfer information from time consecutive configurations is studied, as well as the sensitivity to perturbed initial conditions. The behavior of the cellular automata rules can be grouped in different classes, but no single grouping captures the whole nature of the involved rules. The analysis carried out is particularly appropriate for studying the computational processing capabilities of cellular automata rules.

  3. Evolution of the new vertebrate head by co-option of an ancient chordate skeletal tissue.

    Science.gov (United States)

    Jandzik, David; Garnett, Aaron T; Square, Tyler A; Cattell, Maria V; Yu, Jr-Kai; Medeiros, Daniel M

    2015-02-26

    A defining feature of vertebrates (craniates) is a pronounced head that is supported and protected by a robust cellular endoskeleton. In the first vertebrates, this skeleton probably consisted of collagenous cellular cartilage, which forms the embryonic skeleton of all vertebrates and the adult skeleton of modern jawless and cartilaginous fish. In the head, most cellular cartilage is derived from a migratory cell population called the neural crest, which arises from the edges of the central nervous system. Because collagenous cellular cartilage and neural crest cells have not been described in invertebrates, the appearance of cellular cartilage derived from neural crest cells is considered a turning point in vertebrate evolution. Here we show that a tissue with many of the defining features of vertebrate cellular cartilage transiently forms in the larvae of the invertebrate chordate Branchiostoma floridae (Florida amphioxus). We also present evidence that during evolution, a key regulator of vertebrate cartilage development, SoxE, gained new cis-regulatory sequences that subsequently directed its novel expression in neural crest cells. Together, these results suggest that the origin of the vertebrate head skeleton did not depend on the evolution of a new skeletal tissue, as is commonly thought, but on the spread of this tissue throughout the head. We further propose that the evolution of cis-regulatory elements near an ancient regulator of cartilage differentiation was a major factor in the evolution of the vertebrate head skeleton.

  4. Cellular Automaton Study of Hydrogen Porosity Evolution Coupled with Dendrite Growth During Solidification in the Molten Pool of Al-Cu Alloys

    Science.gov (United States)

    Gu, Cheng; Wei, Yanhong; Yu, Fengyi; Liu, Xiangbo; She, Lvbo

    2017-09-01

    Welding porosity defects significantly reduce the mechanical properties of welded joints. In this paper, the hydrogen porosity evolution coupled with dendrite growth during solidification in the molten pool of Al-4.0 wt pct Cu alloy was modeled and simulated. Three phases, including a liquid phase, a solid phase, and a gas phase, were considered in this model. The growth of dendrites and hydrogen gas pores was reproduced using a cellular automaton (CA) approach. The diffusion of solute and hydrogen was calculated using the finite difference method (FDM). Columnar and equiaxed dendrite growth with porosity evolution were simulated. Competitive growth between different dendrites and porosities was observed. Dendrite morphology was influenced by porosity formation near dendrites. After solidification, when the porosities were surrounded by dendrites, they could not escape from the liquid, and they made pores that existed in the welded joints. With the increase in the cooling rate, the average diameter of porosities decreased, and the average number of porosities increased. The average diameter of porosities and the number of porosities in the simulation results had the same trend as the experimental results.

  5. Emergence of Darwinian theories on evolution of Homo sapiens (Catarrhini: Hominidae and their relevance for social sciences Origen de las teorías darwinianas de la evolución de Homo sapiens (Catarrhini: Hominidae y su importancia para las ciencias sociales

    Directory of Open Access Journals (Sweden)

    GERMÁN MANRÍQUEZ

    2010-12-01

    Full Text Available Despite the great impact that the Darwinian theories on organic evolution have had in the development and consolidation of biology as an autonomous scientific discipline, their relevance in social sciences, and particularly in archaeology and anthropology still remain ambiguous. This ambiguity is reflected in the classical interpretation of Darwin's work pervading Social Sciences during more than one century, according to which the same ideas that contributed to the understanding of natural processes from a scientific perspective would be at the basis of a misleading interpretation of the evolution of human societies due to the application of the principie of natural selection to the social processes. Here we show how the works of T.H. Huxley and A.R. Wallace positively stimulated Darwin to answer to the question about the origin of human populations considering culture from an evolutionary perspective as a factor opposed to the negative action of natural selection on human societies, thus refuting the classical interpretation of Darwin's work made by Social Sciences. The role played by the biocultural approach in understanding human evolution as well as in promoting the integrative thinking in Social Sciences is also discussed.A pesar del enorme impacto que las teorías de Darwin sobre la evolución orgánica han tenido en el desarrollo y la consolidación de la biología como disciplina científica autónoma, su pertinencia en ciencias sociales, y particularmente en arqueología y antropología sigue siendo ambigua. Esta ambigüedad se refleja en la interpretación clásica de la obra de Darwin que ha permanecido en las ciencias sociales durante más de un siglo, según la cual las mismas ideas que contribuyeron a la comprension de los procesos naturales desde una perspectiva científica estarían en la base de una interpretación errónea de la evolución de las sociedades humanas debido a la aplicación del principio de la selección natural

  6. The RNA-world and co-evolution hypothesis and the origin of life: Implications, research strategies and perspectives

    Science.gov (United States)

    Lahav, Noam

    1993-01-01

    The applicability of the RNA-world and co-evolution hypothesis to the study of the very first stages of the origin of life is discussed. The discussion focuses on the basic differences between the two hypotheses and their implications, with regard to the reconstruction methodology, ribosome emergence, balance between ribozymes and protein enzymes, and their major difficultites. Additional complexities of the two hypotheses, such as membranes and the energy source of the first reactions, are not treated in the present work. A central element in the proposed experimental strategies is the study of the catalytic activites of very small peptides and RNA-like oligomers, according to existing, as well as to yet-to-be-invented scenarios of the two hypothesis under consideration. It is suggested that the novel directed molecular evolution technology, and molecular computational modeling, can be applied to this research. This strategy is assumed to be essential for the suggested goal of future studies of the origin of life, namely, the establishment of a `Primordial Darwinian entity'.

  7. The RNA-world and co-evolution hypotheses and the origin of life: Implications, research strategies and perspectives

    Science.gov (United States)

    Lahav, Noam

    1993-12-01

    The applicability of the RNA-world and co-evolution hypotheses to the study of the very first stages of the origin of life is discussed. The discussion focuses on the basic differences between the two hypotheses and their implications, with regard to the reconstruction methodology, ribosome emergence, balance between ribozymes and protein enzymes, and their major difficulties. Additional complexities of the two hypotheses, such as membranes and the energy source of the first reactions, are not treated in the present work. A central element in the proposed experimental strategies is the study of the catalytic activities of very small peptides and RNA-like oligomers, according to existing, as well as to yet-to-be-invented scenarios of the two hypotheses under consideration. It is suggested that the noveldirected molecular evolution technology, andmolecular computational modeling, can be applied to this research. This strategy is assumed to be essential for the suggested goal of future studies of the origin of life, namely, the establishment of a ‘Primordial Darwinian entity’.

  8. Stochastic properties of disturbed Elementary Cellular Automata

    International Nuclear Information System (INIS)

    Posiewnik, M.

    2005-01-01

    Cellular automata are class of simple mathematical systems that generate diverse, often complicated behaviour. Evolution of such a system is given by set of local and deterministic rules. However, in spite of simplicity of 'interactions' it's global behaviour can't be, in general, simply predicted or even can not be predicted in time shorter that time of it's strict evolution. We get as, a systems well known 1-dimensional, Wolfram class automata, and connect it into the reservoir consists of some random source (noise). In our experiment we are interested in: a) numeric verification of ergodicity for such a coupled system. b) finding it's probability distribution and evolution. c) finding some analogous for 'real' quantities and behaviour. d) using the dynamical systems and Markov chains theory to describe the system, and to make any predictions of it's behaviour. (author)

  9. Bayesian Methods and Universal Darwinism

    Science.gov (United States)

    Campbell, John

    2009-12-01

    Bayesian methods since the time of Laplace have been understood by their practitioners as closely aligned to the scientific method. Indeed a recent Champion of Bayesian methods, E. T. Jaynes, titled his textbook on the subject Probability Theory: the Logic of Science. Many philosophers of science including Karl Popper and Donald Campbell have interpreted the evolution of Science as a Darwinian process consisting of a `copy with selective retention' algorithm abstracted from Darwin's theory of Natural Selection. Arguments are presented for an isomorphism between Bayesian Methods and Darwinian processes. Universal Darwinism, as the term has been developed by Richard Dawkins, Daniel Dennett and Susan Blackmore, is the collection of scientific theories which explain the creation and evolution of their subject matter as due to the Operation of Darwinian processes. These subject matters span the fields of atomic physics, chemistry, biology and the social sciences. The principle of Maximum Entropy states that Systems will evolve to states of highest entropy subject to the constraints of scientific law. This principle may be inverted to provide illumination as to the nature of scientific law. Our best cosmological theories suggest the universe contained much less complexity during the period shortly after the Big Bang than it does at present. The scientific subject matter of atomic physics, chemistry, biology and the social sciences has been created since that time. An explanation is proposed for the existence of this subject matter as due to the evolution of constraints in the form of adaptations imposed on Maximum Entropy. It is argued these adaptations were discovered and instantiated through the Operations of a succession of Darwinian processes.

  10. Cellular structure of lean hydrogen flames in microgravity

    Science.gov (United States)

    Patnaik, G.; Kailasanath, K.

    1990-01-01

    Detailed, time-dependent, two-dimensional numerical simulations of premixed laminar flames have been used to study the initiation and subsequent development of cellular structures in lean hydrogen-air flames. The model includes detailed hydrogen-oxygen combustion with 24 elementary reactions of eight reactive species and a nitrogen diluent, molecular diffusion of all species, thermal conduction, viscosity, and convection. This model has been used to study the nonlinear evolution of cellular flame structure and shows that cell splitting, as observed in experiments, can be predicted numerically for sufficiently reactive mixtures. The structures that evolved also resembled the cellular structures observed in experiments. The present study shows that the 'cell-split limit' postulated from experimental observations is an intrinsic property of the mixture and that external factors such as heat losses are not necessary to cause this limit.

  11. Mode and tempo in the evolution of socio-political organization: reconciling ‘Darwinian’ and ‘Spencerian’ evolutionary approaches in anthropology

    Science.gov (United States)

    Currie, Thomas E.; Mace, Ruth

    2011-01-01

    Traditional investigations of the evolution of human social and political institutions trace their ancestry back to nineteenth century social scientists such as Herbert Spencer, and have concentrated on the increase in socio-political complexity over time. More recent studies of cultural evolution have been explicitly informed by Darwinian evolutionary theory and focus on the transmission of cultural traits between individuals. These two approaches to investigating cultural change are often seen as incompatible. However, we argue that many of the defining features and assumptions of ‘Spencerian’ cultural evolutionary theory represent testable hypotheses that can and should be tackled within a broader ‘Darwinian’ framework. In this paper we apply phylogenetic comparative techniques to data from Austronesian-speaking societies of Island South-East Asia and the Pacific to test hypotheses about the mode and tempo of human socio-political evolution. We find support for three ideas often associated with Spencerian cultural evolutionary theory: (i) political organization has evolved through a regular sequence of forms, (ii) increases in hierarchical political complexity have been more common than decreases, and (iii) political organization has co-evolved with the wider presence of hereditary social stratification. PMID:21357233

  12. Discovery of a distinct superfamily of Kunitz-type toxin (KTT from tarantulas.

    Directory of Open Access Journals (Sweden)

    Chun-Hua Yuan

    Full Text Available BACKGROUND: Kuntiz-type toxins (KTTs have been found in the venom of animals such as snake, cone snail and sea anemone. The main ancestral function of Kunitz-type proteins was the inhibition of a diverse array of serine proteases, while toxic activities (such as ion-channel blocking were developed under a variety of Darwinian selection pressures. How new functions were grafted onto an old protein scaffold and what effect Darwinian selection pressures had on KTT evolution remains a puzzle. PRINCIPAL FINDINGS: Here we report the presence of a new superfamily of ktts in spiders (TARANTULAS: Ornithoctonus huwena and Ornithoctonus hainana, which share low sequence similarity to known KTTs and is clustered in a distinct clade in the phylogenetic tree of KTT evolution. The representative molecule of spider KTTs, HWTX-XI, purified from the venom of O. huwena, is a bi-functional protein which is a very potent trypsin inhibitor (about 30-fold more strong than BPTI as well as a weak Kv1.1 potassium channel blocker. Structural analysis of HWTX-XI in 3-D by NMR together with comparative function analysis of 18 expressed mutants of this toxin revealed two separate sites, corresponding to these two activities, located on the two ends of the cone-shape molecule of HWTX-XI. Comparison of non-synonymous/synonymous mutation ratios (omega for each site in spider and snake KTTs, as well as PBTI like body Kunitz proteins revealed high Darwinian selection pressure on the binding sites for Kv channels and serine proteases in snake, while only on the proteases in spider and none detected in body proteins, suggesting different rates and patterns of evolution among them. The results also revealed a series of key events in the history of spider KTT evolution, including the formation of a novel KTT family (named sub-Kuntiz-type toxins derived from the ancestral native KTTs with the loss of the second disulfide bridge accompanied by several dramatic sequence modifications

  13. Schrodinger's cat versus Darwin

    OpenAIRE

    Silagadze, Z. K.

    2009-01-01

    Sun Wu-k'ung, an immortal Monkey-King of Chaos learns modern physics from the Patriarch Bodhi and questions the Darwinian evolution. He finds that the modern physics indicates towards the intelligent design as a vastly more probably origin of humans than the random evolution by mutations and natural selection.

  14. Danes commemorating Darwin: apes and evolution at the 1909 anniversary.

    Science.gov (United States)

    Hjermitslev, Hans Henrik

    2010-10-01

    This article analyses the Danish 1909 celebrations of the centenary of Charles Darwin's birth on 12 February 1809. I argue that the 1909 meetings, lectures and publications devoted to Darwin and his theory of evolution by natural selection can be characterised by ambivalence: on the one hand, tribute to a great man of science who established a new view of nature and, on the other hand, scepticism towards the Darwinian mechanism of natural selection and the wider religious and political implications drawn from his theory. The article examines both professional and popular commemorative activities, focusing primarily on celebratory articles carried in widely circulated magazines and newspapers. I identify three types of interpretations of Darwin's ideas which I characterise as 'radical', 'evangelical' and 'safe' science. These different positions were closely linked to the political and cultural divisions of the periodical press. Moreover, my analysis of the popular press offers a solid basis for asserting that to most people Darwinism was associated with human evolution, primarily the relationship between man and apes, while more sophisticated discussions about the crisis of Darwinism prominent among naturalists played only a secondary role in the public arena. This article demonstrates the value of using newspapers as historical sources when looking for public images of Darwin, popular receptions of Darwinism and representations of science in general.

  15. [Social institutions and tempering of affects as "contraints" of social change. Norbert Elias' theory on the civilization theory in light of the biologic system theory of evolution].

    Science.gov (United States)

    Weinich, Detlef

    2005-01-01

    This study is to be regarded as a contribution to interdisciplinary research and represents an attempt to clarify the question of whether and to what extent concepts that have been developed in the field of theoretical biology and which have a high degree of importance here can also be applied to sociological phenomena. In particular it is intended to examine the question of whether the civilizing process can be adequately treated using the evolutionary concept of "Constraints". This term, which has only recently been introduced into the discussion by PERE ALBERCH as an evolutionary factor, comprises all of the internal factors which influence the further course of the evolution of a system by ruling out certain possibilities, thus showing a limiting effect. Although "Constraints" go beyond the scope of Darwinian teachings about selection by the environment, they are increasingly accepted today as evolution factors by well-known exponents of Darwinian theory (cf. MAYNARD-SMITH 1985). The increase in popularity of "constraints" is also an expression of the rediscovery of a phenomenon which was originally expressed by RUPERT RIEDL and was introduced by him into German literature in the seventies. In the clarification of this question, special reference is made to the "theory of the civilizing process" by NORBERT ELIAS, since here a highly respected scholar has presented an important sociological theory. Moreover, there is such good scientific access to ELIAS because this author exemplifies his theses in historical terms and thus to a certain extent makes his explanations verifiable in scientific terms. In the treatment of this topic, the central terms and theses of ELIAS will be presented from the considerable scope of his work, and then illustrated with the help of several selected historical case studies. Furthermore, reference will be made at the relevant points to parallels and analogies which the works of ELIAS have to other, predominantly system

  16. Dualities for multi-state probabilistic cellular automata

    International Nuclear Information System (INIS)

    López, F Javier; Sanz, Gerardo; Sobottka, Marcelo

    2008-01-01

    In this paper a new form of duality for probabilistic cellular automata (PCA) is introduced. Using this duality, an ergodicity result for processes having a dual is proved. Also, conditions on the probabilities defining the evolution of the processes for the existence of a dual are provided. The results are applied to wide classes of PCA which include multi-opinion voter models, competition models and the Domany–Kinzel model

  17. Science for Survival: The Modern Synthesis of Evolution and The Biological Sciences Curriculum Study

    Science.gov (United States)

    Green, Lisa Anne

    In this historical dissertation, I examined the process of curriculum development in the Biological Sciences Curriculum Study (BSCS) in the United States during the period 1959-1963. The presentation of evolution in the high school texts was based on a more robust form of Darwinian evolution which developed during the 1930s and 1940s called "the modern synthesis of evolution." Building primarily on the work of historians Vassiliki Smocovitis and John L. Rudolph, I used the archival papers and published writings of the four architects of the modern synthesis and the four most influential leaders of the BSCS in regards to evolution to investigate how the modern synthetic theory of evolution shaped the BSCS curriculum. The central question was "Why was evolution so important to the BSCS to make it the central theme of the texts?" Important answers to this question had already been offered in the historiography, but it was still not clear why every citizen in the world needed to understand evolution. I found that the emphasis on natural selection in the modern synthesis shifted the focus away from humans as passive participants to the recognition that humans are active agents in their own cultural and biological evolution. This required re-education of the world citizenry, which was accomplished in part by the BSCS textbooks. I also found that BSCS leaders Grobman, Glass, and Muller had serious concerns regarding the effects of nuclear radiation on the human gene pool, and were actively involved in informing th public. Lastly, I found that concerns of 1950s reform eugenicists were addressed in the BSCS textbooks, without mentioning eugenics by name. I suggest that the leaders of the BSCS, especially Bentley Glass and Hermann J. Muller, thought that students needed to understand genetics and evolution to be able to make some of the tough choices they might be called on to make as the dominant species on earth and the next reproductive generation in the nuclear age. This

  18. [Historic and functional biology: the inadequacy of a system theory of evolution].

    Science.gov (United States)

    Regelmann, J P

    1982-01-01

    In the first half of the 20th century neo-Kantianism in a broad sense proved itself the main conceptual and methodological background of the central European biology. As such it contributed much to the victory on the typological, idealistic-morphological and psycho-vitalistic interpretations of life. On the other hand it could not give tools to the biologists for working out a strictly darwinian evolution theory. Kant's theory of organism was conceived without evolution as a theory of the internal functionality of the organism. There was only some 'play' with the evolutionary differentiation of the species. Since then the disputes around the work of August Weismann, a synthetical evolution theory which is now behind time, arose. This theory developed from coinciding claims, elaborated by geneticists, mathematicians, and by biologists studying development, natural history and systematics. This was done under a strong influence of marxist ideas. Through the interweaving of such different approaches it was possible for this evolutionary synthesis to influence successfully the development of evolution research during more than 40 years. Philosophically speaking modern evolution theory means therefore an aversion, even a positive abolition of Kantian positions. A number of biologists however--as L. von Bertalanffy--refused to adhere to a misinterpreted Kantian methodology and oriented themselves to an approach via system theory, which obtained a place in evolution research. In fact this is a Kantian approach as well. They only repeated the Kantian dilemma of the evolution which can also be found in Lamarck and Hegel. The system theory of the functionality of the organism never reaches to the level of the evolving species, but remains always on the level of epigenetic thinking, because of its philosophical origin. This paper points out the consequences of this still current dilemma. At the same time an all-enclosing reflection on the methodological, epistemological and

  19. Image Encryption Scheme Based on Balanced Two-Dimensional Cellular Automata

    Directory of Open Access Journals (Sweden)

    Xiaoyan Zhang

    2013-01-01

    Full Text Available Cellular automata (CA are simple models of computation which exhibit fascinatingly complex behavior. Due to the universality of CA model, it has been widely applied in traditional cryptography and image processing. The aim of this paper is to present a new image encryption scheme based on balanced two-dimensional cellular automata. In this scheme, a random image with the same size of the plain image to be encrypted is first generated by a pseudo-random number generator with a seed. Then, the random image is evoluted alternately with two balanced two-dimensional CA rules. At last, the cipher image is obtained by operating bitwise XOR on the final evolution image and the plain image. This proposed scheme possesses some advantages such as very large key space, high randomness, complex cryptographic structure, and pretty fast encryption/decryption speed. Simulation results obtained from some classical images at the USC-SIPI database demonstrate the strong performance of the proposed image encryption scheme.

  20. Coupled pulsating and cellular structure in the propagation of globally planar detonations in free space

    International Nuclear Information System (INIS)

    Han, Wenhu; Gao, Yang; Wang, Cheng; Law, Chung K.

    2015-01-01

    The globally planar detonation in free space is numerically simulated, with particular interest to understand and quantify the emergence and evolution of the one-dimensional pulsating instability and the two-dimensional cellular structure which is inherently also affected by pulsating instability. It is found that the pulsation includes three stages: rapid decay of the overdrive, approach to the Chapman-Jouguet state and emergence of weak pulsations, and the formation of strong pulsations; while evolution of the cellular structure also exhibits distinct behavior at these three stages: no cell formation, formation of small-scale, irregular cells, and formation of regular cells of a larger scale. Furthermore, the average shock pressure in the detonation front consists of fine-scale oscillations reflecting the collision dynamics of the triple-shock structure and large-scale oscillations affected by the global pulsation. The common stages of evolution between the cellular structure and the pulsating behavior, as well as the existence of shock-front pressure oscillation, suggest highly correlated mechanisms between them. Detonations with period doubling, period quadrupling, and chaotic amplitudes were also observed and studied for progressively increasing activation energies

  1. Fulltext PDF

    Indian Academy of Sciences (India)

    Anthropic Principle, Terrestrial Complexity, Complex Materials. V K Wadhawan .... Once life had originated, Darwinian evolution of complexity through natural selection ..... reactors, based on totally new approaches, are in the pipeline. But can ...

  2. Economic Selection Theory

    DEFF Research Database (Denmark)

    Knudsen, Thorbjørn

    2003-01-01

    principles of variation, continuity and selection, it is argued that economic selection theory should mimic the causal structure of neo-Darwinian theory. Two of the most influential explanations of economic evolution, Alchian's and Nelson and Winter's, are used to illustrate how this could be achieved.......The present article provides a minimal description of the causal structure of economic selection theory and outlines how the internal selection dynamics of business organisations can be reconciled with selection in competitive markets. In addition to generic similarity in terms of the Darwinian...

  3. Cancer tumors as Metazoa 1.0: tapping genes of ancient ancestors

    International Nuclear Information System (INIS)

    Davies, P C W; Lineweaver, C H

    2011-01-01

    The genes of cellular cooperation that evolved with multicellularity about a billion years ago are the same genes that malfunction to cause cancer. We hypothesize that cancer is an atavistic condition that occurs when genetic or epigenetic malfunction unlocks an ancient 'toolkit' of pre-existing adaptations, re-establishing the dominance of an earlier layer of genes that controlled loose-knit colonies of only partially differentiated cells, similar to tumors. The existence of such a toolkit implies that the progress of the neoplasm in the host organism differs distinctively from normal Darwinian evolution. Comparative genomics and the phylogeny of basal metazoans, opisthokonta and basal multicellular eukaryotes should help identify the relevant genes and yield the order in which they evolved. This order will be a rough guide to the reverse order in which cancer develops, as mutations disrupt the genes of cellular cooperation. Our proposal is consistent with current understanding of cancer and explains the paradoxical rapidity with which cancer acquires a suite of mutually-supportive complex abilities. Finally we make several predictions and suggest ways to test this model

  4. FPGA Implementation of one-dimensional and two-dimensional cellular automata

    International Nuclear Information System (INIS)

    D'Antone, I.

    1999-01-01

    This report describes the hardware implementation of one-dimensional and two-dimensional cellular automata (CAs). After a general introduction to the cellular automata, we consider a one-dimensional CA used to implement pseudo-random techniques in built-in self test for VLSI. Due to the increase in digital ASIC complexity, testing is becoming one of the major costs in the VLSI production. The high electronics complexity, used in particle physics experiments, demands higher reliability than in the past time. General criterions are given to evaluate the feasibility of the circuit used for testing and some quantitative parameters are underlined to optimize the architecture of the cellular automaton. Furthermore, we propose a two-dimensional CA that performs a peak finding algorithm in a matrix of cells mapping a sub-region of a calorimeter. As in a two-dimensional filtering process, the peaks of the energy clusters are found in one evolution step. This CA belongs to Wolfram class II cellular automata. Some quantitative parameters are given to optimize the architecture of the cellular automaton implemented in a commercial field programmable gate array (FPGA)

  5. Homo sapiens as physician and patient: a view from Darwinian medicine.

    Science.gov (United States)

    Román-Franco, Angel A

    2013-09-01

    Medicine's cardinal diagnostic and therapeutic resource is the clinical encounter. Over the last two centuries and particularly over the last five decades the function of the clinical encounter has been eroded to the point of near irrelevance because of the atomized and atomizing influence of technology and microspecialization. Meanwhile, over the past five decades the exceptionalist view of Homo sapiens inherent in the social and religious traditions of the West has similarly undergone radical changes. H. sapiens is now best understood as a microecosystem integrated into a much broader ecosystem: the biosphere. That human microecosystem is composed of constituents derived from the archaeal, bacterial, and eukaryan domains via endosymbiotic, commensalistic and mutualistic interactions. This amalgamation of 100 trillion cells and viral elements is regulated by a composite genome aggregated over the 3.8 billion years of evolutionary history of organic life. No component of H. sapiens or its genome can be identified as irreducibly and exclusively human. H. sapiens' humanity is an emergent property of the microecosystem. Ironically as H. sapiens is viewed by evolutionary science in a highly integrated manner medicine approaches it as a balkanized, deaggregated entity through the eye of 150 different specialties. To effectively address the needs of H sapiens in its role as patient by the same species in its role as physician the disparate views must be harmonized. Here I review some conceptual elements that would assist a physician in addressing the needs of the patient in integrum, as a microecosystem, by the former address the latter as a historical gestalt being. The optimal way to recover the harmony between patient and physician is through a revitalization of the clinical encounter via an ecological and Darwinian epistemology.

  6. Dairy production and sources of cellular variability of milk of cow's in ...

    African Journals Online (AJOL)

    ) of milk, accompanied by an analysis , so some quantitative and qualitative milk parameters that a number of physiological and zootechnical factors of cellular evolution, was performed on two large cattle farms conducted in semi-arid coastal ...

  7. Symmetry pattern transition in cellular automata with complex behavior

    International Nuclear Information System (INIS)

    Sanchez, Juan R.; Lopez-Ruiz, Ricardo

    2008-01-01

    A transition from asymmetric to symmetric patterns in time-dependent extended systems is described. It is shown that one dimensional cellular automata, started from fully random initial conditions, can be forced to evolve into complex symmetrical patterns by stochastically coupling a proportion p of pairs of sites located at equal distance from the center of the lattice. A nontrivial critical value of p must be surpassed in order to obtain symmetrical patterns during the evolution. This strategy is able to classify the cellular automata rules - with complex behavior - between those that support time-dependent symmetric patterns and those which do not support such kind of patterns

  8. The evolutionist debate in Spain during the nineteenth century: a re-examination.

    Science.gov (United States)

    Puig-Samper, Miguel Ángel; García González, Armando; Pelayo, Francisco

    2017-01-01

    This article re-examines the research on evolutionism in Spain and updates knowledge on this topic in light of the work of Thomas Glick, the more philosophical work of Diego Núñez and contributions in recent years from the Latin American network of historians of biology and evolution, who have dealt with the more polemical aspects of the reception of evolution theory. It includes new arguments, such as identification of the drawings in El Museo Universal, whose Lamarckian or Darwinian nature has been a subject of ongoing debate. It also covers the crucial role of the acceptance of Haeckel's work in Spain in comparison to the weaker support for a strictly Darwinian perspective, the role of the Spanish histology school, and the impact of evolutionism on literature.

  9. Neuron-Based Heredity and Human Evolution

    Directory of Open Access Journals (Sweden)

    Don Marshall Gash

    2015-06-01

    Full Text Available Abstract:Abstract: It is widely recognized that human evolution has been driven by two systems of heredity: one DNA-based and the other based on the transmission of behaviorally acquired information via nervous system functions. The genetic system is ancient, going back to the appearance of life on Earth. It is responsible for the evolutionary processes described by Darwin. By comparison, the nervous system is relatively newly minted and in its highest form, responsible for ideation and mind-to-mind transmission of information. Here the informational capabilities and functions of the two systems are compared. While employing quite different mechanisms for encoding, storing and transmission of information, both systems perform these generic hereditary functions. Three additional features of neuron-based heredity in humans are identified: the ability to transfer hereditary information to other members of their population, not just progeny; a selection process for the information being transferred; and a profoundly shorter time span for creation and dissemination of survival-enhancing information in a population. The mechanisms underlying neuron-based heredity involve hippocampal neurogenesis and memory and learning processes modifying and creating new neural assemblages changing brain structure and functions. A fundamental process in rewiring brain circuitry is through increased neural activity (use strengthening and increasing the number of synaptic connections. Decreased activity in circuitry (disuse leads to loss of synapses. Use and disuse modifying an organ to bring about new modes of living, habits and functions are processes are in line with Neolamarckian concepts of evolution (Packard, 1901. Evidence is presented of bipartite evolutionary processes – Darwinian and Neolamarckian – driving human descent from a common ancestor shared with the great apes.

  10. On the holistic approach in cellular and cancer biology: nonlinearity, complexity, and quasi-determinism of the dynamic cellular network.

    Science.gov (United States)

    Waliszewski, P; Molski, M; Konarski, J

    1998-06-01

    A keystone of the molecular reductionist approach to cellular biology is a specific deductive strategy relating genotype to phenotype-two distinct categories. This relationship is based on the assumption that the intermediary cellular network of actively transcribed genes and their regulatory elements is deterministic (i.e., a link between expression of a gene and a phenotypic trait can always be identified, and evolution of the network in time is predetermined). However, experimental data suggest that the relationship between genotype and phenotype is nonbijective (i.e., a gene can contribute to the emergence of more than just one phenotypic trait or a phenotypic trait can be determined by expression of several genes). This implies nonlinearity (i.e., lack of the proportional relationship between input and the outcome), complexity (i.e. emergence of the hierarchical network of multiple cross-interacting elements that is sensitive to initial conditions, possesses multiple equilibria, organizes spontaneously into different morphological patterns, and is controlled in dispersed rather than centralized manner), and quasi-determinism (i.e., coexistence of deterministic and nondeterministic events) of the network. Nonlinearity within the space of the cellular molecular events underlies the existence of a fractal structure within a number of metabolic processes, and patterns of tissue growth, which is measured experimentally as a fractal dimension. Because of its complexity, the same phenotype can be associated with a number of alternative sequences of cellular events. Moreover, the primary cause initiating phenotypic evolution of cells such as malignant transformation can be favored probabilistically, but not identified unequivocally. Thermodynamic fluctuations of energy rather than gene mutations, the material traits of the fluctuations alter both the molecular and informational structure of the network. Then, the interplay between deterministic chaos, complexity, self

  11. Darwin's invisible hand: Market competition, evolution and the firm

    NARCIS (Netherlands)

    Johnson, D. D. P.; Price, M. E.; van Vugt, M.

    2013-01-01

    Competition among firms has been suggested to reflect the ruthless logic of Darwinian selection: a free market is a struggle for survival, in which successful firms survive and unsuccessful ones die. This view appears to bolster three pillars of neoclassical economics: (1) that economic actors are

  12. NED-DARWINIAN ACCOUNTS OF mE EVOLUTION OF LANGUAGE ...

    African Journals Online (AJOL)

    echo-location or stereopsis, and that the only way to explain the origin of such abilities is ...... explanation. They force me into a position from which I can only criticize ..... The emergence of homo loquens and the laws of physics. Behavioral.

  13. The remarkable discreteness of being

    Indian Academy of Sciences (India)

    2014-03-15

    Mar 15, 2014 ... In biology, the theory of Darwinian evolution was inconsistent with the then obvious blending theory ..... A self-consistent model of geographical ... Wilson model and can be put to experimental verification. Improving the above ...

  14. The theory of evolution - a jewish perspective.

    Science.gov (United States)

    Steinberg, Avraham

    2010-07-01

    All possible pro and con arguments regarding the theory of evolution have been discussed and debated in the vast literature-scientific, religious, and lay-in the past 150 years. There is usually great zealotry in all debating parties, with mutual intolerance of ideas and concepts, disrespect toward opposing opinions and positions, and usage of very harsh language. This prejudiced approach usually does not allow for a reasonable debate. It is important to look at the facts, assumptions, and beliefs of the theory of evolution in a more calm and humble way. In this article a comparative analysis is offered between the scientific aspects of the theory of evolution and a Judaic approach to these aspects. The two sets of human thought-religion and science-are fundamentally different in their aims and purposes, in their methods of operation, in their scope of interest and issues, and in their origin and ramifications. Whenever science surpasses its limits, or religion exceeds its boundaries, it actually is a form of an abuse of both. This has happened to the theory of evolution in a more powerful mode than any other interaction between science and religion. The agenda of many scientists who promote the theory of evolution is to achieve the goal of understanding the existence of the universe as a random, purposeless, natural development, evolved slowly over billions of years from a common ancestor by way of natural selection, devoid of any supernatural metaphysical power. JEWISH FAITH PERCEIVES THE DEVELOPMENT OF THE UNIVERSE IN A DIFFERENT WAY: God created the world, with a purpose known to Him; He established natural laws that govern the world; and He imposed a moral-religious set of requirements upon Man. The discussion and comparative analysis in this article is based upon the current neo-Darwinian theory, although it seems almost certain that even the new and modern assumptions and speculations will continue to be challenged, changed, and revised as new scientific

  15. The Theory of Evolution - A Jewish Perspective

    Directory of Open Access Journals (Sweden)

    Avraham Steinberg

    2010-07-01

    Full Text Available All possible pro and con arguments regarding the theory of evolution have been discussed and debated in the vast literature—scientific, religious, and lay—in the past 150 years. There is usually great zealotry in all debating parties, with mutual intolerance of ideas and concepts, disrespect toward opposing opinions and positions, and usage of very harsh language. This prejudiced approach usually does not allow for a reasonable debate. It is important to look at the facts, assumptions, and beliefs of the theory of evolution in a more calm and humble way. In this article a comparative analysis is offered between the scientific aspects of the theory of evolution and a Judaic approach to these aspects. The two sets of human thought—religion and science—are fundamentally different in their aims and purposes, in their methods of operation, in their scope of interest and issues, and in their origin and ramifications. Whenever science surpasses its limits, or religion exceeds its boundaries, it actually is a form of an abuse of both. This has happened to the theory of evolution in a more powerful mode than any other interaction between science and religion. The agenda of many scientists who promote the theory of evolution is to achieve the goal of understanding the existence of the universe as a random, purposeless, natural development, evolved slowly over billions of years from a common ancestor by way of natural selection, devoid of any supernatural metaphysical power. Jewish faith perceives the development of the universe in a different way: God created the world, with a purpose known to Him; He established natural laws that govern the world; and He imposed a moral-religious set of requirements upon Man. The discussion and comparative analysis in this article is based upon the current neo-Darwinian theory, although it seems almost certain that even the new and modern assumptions and speculations will continue to be challenged, changed, and

  16. The Theory of Evolution - A Jewish Perspective

    Science.gov (United States)

    Steinberg, Avraham

    2010-01-01

    All possible pro and con arguments regarding the theory of evolution have been discussed and debated in the vast literature—scientific, religious, and lay—in the past 150 years. There is usually great zealotry in all debating parties, with mutual intolerance of ideas and concepts, disrespect toward opposing opinions and positions, and usage of very harsh language. This prejudiced approach usually does not allow for a reasonable debate. It is important to look at the facts, assumptions, and beliefs of the theory of evolution in a more calm and humble way. In this article a comparative analysis is offered between the scientific aspects of the theory of evolution and a Judaic approach to these aspects. The two sets of human thought—religion and science—are fundamentally different in their aims and purposes, in their methods of operation, in their scope of interest and issues, and in their origin and ramifications. Whenever science surpasses its limits, or religion exceeds its boundaries, it actually is a form of an abuse of both. This has happened to the theory of evolution in a more powerful mode than any other interaction between science and religion. The agenda of many scientists who promote the theory of evolution is to achieve the goal of understanding the existence of the universe as a random, purposeless, natural development, evolved slowly over billions of years from a common ancestor by way of natural selection, devoid of any supernatural metaphysical power. Jewish faith perceives the development of the universe in a different way: God created the world, with a purpose known to Him; He established natural laws that govern the world; and He imposed a moral-religious set of requirements upon Man. The discussion and comparative analysis in this article is based upon the current neo-Darwinian theory, although it seems almost certain that even the new and modern assumptions and speculations will continue to be challenged, changed, and revised as new

  17. The cosmological model of eternal inflation and the transition from chance to biological evolution in the history of life

    Directory of Open Access Journals (Sweden)

    Koonin Eugene V

    2007-05-01

    Full Text Available Abstract Background Recent developments in cosmology radically change the conception of the universe as well as the very notions of "probable" and "possible". The model of eternal inflation implies that all macroscopic histories permitted by laws of physics are repeated an infinite number of times in the infinite multiverse. In contrast to the traditional cosmological models of a single, finite universe, this worldview provides for the origin of an infinite number of complex systems by chance, even as the probability of complexity emerging in any given region of the multiverse is extremely low. This change in perspective has profound implications for the history of any phenomenon, and life on earth cannot be an exception. Hypothesis Origin of life is a chicken and egg problem: for biological evolution that is governed, primarily, by natural selection, to take off, efficient systems for replication and translation are required, but even barebones cores of these systems appear to be products of extensive selection. The currently favored (partial solution is an RNA world without proteins in which replication is catalyzed by ribozymes and which serves as the cradle for the translation system. However, the RNA world faces its own hard problems as ribozyme-catalyzed RNA replication remains a hypothesis and the selective pressures behind the origin of translation remain mysterious. Eternal inflation offers a viable alternative that is untenable in a finite universe, i.e., that a coupled system of translation and replication emerged by chance, and became the breakthrough stage from which biological evolution, centered around Darwinian selection, took off. A corollary of this hypothesis is that an RNA world, as a diverse population of replicating RNA molecules, might have never existed. In this model, the stage for Darwinian selection is set by anthropic selection of complex systems that rarely but inevitably emerge by chance in the infinite universe

  18. The cosmological model of eternal inflation and the transition from chance to biological evolution in the history of life.

    Science.gov (United States)

    Koonin, Eugene V

    2007-05-31

    Recent developments in cosmology radically change the conception of the universe as well as the very notions of "probable" and "possible". The model of eternal inflation implies that all macroscopic histories permitted by laws of physics are repeated an infinite number of times in the infinite multiverse. In contrast to the traditional cosmological models of a single, finite universe, this worldview provides for the origin of an infinite number of complex systems by chance, even as the probability of complexity emerging in any given region of the multiverse is extremely low. This change in perspective has profound implications for the history of any phenomenon, and life on earth cannot be an exception. Origin of life is a chicken and egg problem: for biological evolution that is governed, primarily, by natural selection, to take off, efficient systems for replication and translation are required, but even barebones cores of these systems appear to be products of extensive selection. The currently favored (partial) solution is an RNA world without proteins in which replication is catalyzed by ribozymes and which serves as the cradle for the translation system. However, the RNA world faces its own hard problems as ribozyme-catalyzed RNA replication remains a hypothesis and the selective pressures behind the origin of translation remain mysterious. Eternal inflation offers a viable alternative that is untenable in a finite universe, i.e., that a coupled system of translation and replication emerged by chance, and became the breakthrough stage from which biological evolution, centered around Darwinian selection, took off. A corollary of this hypothesis is that an RNA world, as a diverse population of replicating RNA molecules, might have never existed. In this model, the stage for Darwinian selection is set by anthropic selection of complex systems that rarely but inevitably emerge by chance in the infinite universe (multiverse). The plausibility of different models

  19. The ancient Virus World and evolution of cells

    Directory of Open Access Journals (Sweden)

    Dolja Valerian V

    2006-09-01

    Full Text Available Abstract Background Recent advances in genomics of viruses and cellular life forms have greatly stimulated interest in the origins and evolution of viruses and, for the first time, offer an opportunity for a data-driven exploration of the deepest roots of viruses. Here we briefly review the current views of virus evolution and propose a new, coherent scenario that appears to be best compatible with comparative-genomic data and is naturally linked to models of cellular evolution that, from independent considerations, seem to be the most parsimonious among the existing ones. Results Several genes coding for key proteins involved in viral replication and morphogenesis as well as the major capsid protein of icosahedral virions are shared by many groups of RNA and DNA viruses but are missing in cellular life forms. On the basis of this key observation and the data on extensive genetic exchange between diverse viruses, we propose the concept of the ancient virus world. The virus world is construed as a distinct contingent of viral genes that continuously retained its identity throughout the entire history of life. Under this concept, the principal lineages of viruses and related selfish agents emerged from the primordial pool of primitive genetic elements, the ancestors of both cellular and viral genes. Thus, notwithstanding the numerous gene exchanges and acquisitions attributed to later stages of evolution, most, if not all, modern viruses and other selfish agents are inferred to descend from elements that belonged to the primordial genetic pool. In this pool, RNA viruses would evolve first, followed by retroid elements, and DNA viruses. The Virus World concept is predicated on a model of early evolution whereby emergence of substantial genetic diversity antedates the advent of full-fledged cells, allowing for extensive gene mixing at this early stage of evolution. We outline a scenario of the origin of the main classes of viruses in conjunction

  20. Quantum features of natural cellular automata

    International Nuclear Information System (INIS)

    Elze, Hans-Thomas

    2016-01-01

    Cellular automata can show well known features of quantum mechanics, such as a linear rule according to which they evolve and which resembles a discretized version of the Schrödinger equation. This includes corresponding conservation laws. The class of “natural” Hamiltonian cellular automata is based exclusively on integer-valued variables and couplings and their dynamics derives from an Action Principle. They can be mapped reversibly to continuum models by applying Sampling Theory. Thus, “deformed” quantum mechanical models with a finite discreteness scale l are obtained, which for l → 0 reproduce familiar continuum results. We have recently demonstrated that such automata can form “multipartite” systems consistently with the tensor product structures of nonrelativistic many-body quantum mechanics, while interacting and maintaining the linear evolution. Consequently, the Superposition Principle fully applies for such primitive discrete deterministic automata and their composites and can produce the essential quantum effects of interference and entanglement. (paper)

  1. Ethic and Evolution in Boltzmann's and Einstein's Thought

    Energy Technology Data Exchange (ETDEWEB)

    Broda, E.

    1980-07-01

    In physics and to a large extent in epistomology, Einstein was the natural successor to Boltzmann. But while Boltzmann was an ardent evolutionist, Einstein cared little for biology. Boltzmann applied Darwinian principles also to ethics, but remained aloof from politics. In contrast, Einstein's morality, though expressed in magnificent and selfless activity, lacked a firm theoretical basis. (author)

  2. Ethic and Evolution in Boltzmann's and Einstein's Thought

    International Nuclear Information System (INIS)

    Broda, E.

    1980-01-01

    In physics and to a large extent in epistomology, Einstein was the natural successor to Boltzmann. But while Boltzmann was an ardent evolutionist, Einstein cared little for biology. Boltzmann applied Darwinian principles also to ethics, but remained aloof from politics. In contrast, Einstein's morality, though expressed in magnificent and selfless activity, lacked a firm theoretical basis. (author)

  3. Fine Tuning Mission to reach those influenced by Darwinism

    Directory of Open Access Journals (Sweden)

    Roger Tucker

    2014-01-01

    Full Text Available The scientifically aware section of the South African population is increasing. Many are being exposed to the concept of Darwinian evolution. Exposure has generated a religious sub �people group� who have problems with Christianity because they have been influenced by the naturalistic element in Darwinian philosophy. Christian antagonism towards evolution has often prejudiced them unfavourably towards the gospel. Recent discoveries concerning the fine-tuning of the universe have now presented a window of opportunity for overcoming this. It may enable the church to �fine-tune� its missionary approach to present them with the gospel in a more acceptable manner. It is suggested that Paul�s Areopagus speech provides a model for such cross-cultural evangelism. A section is included at the end, describing some objections that have been raised against the cosmological fine-tuning apologetic.

  4. Claiming Darwin: Stephen Jay Gould in contests over evolutionary orthodoxy and public perception, 1977-2002.

    Science.gov (United States)

    Sheldon, Myrna Perez

    2014-03-01

    This article analyzes the impact of the resurgence of American creationism in the early 1980s on debates within post-synthesis evolutionary biology. During this period, many evolutionists criticized Harvard biologist Stephen Jay Gould for publicizing his revisions to traditional Darwinian theory and opening evolution to criticism by creationists. Gould's theory of punctuated equilibrium was a significant source of contention in these disputes. Both he and his critics, including Richard Dawkins, claimed to be carrying the mantle of Darwinian evolution. By the end of the 1990s, the debate over which evolutionary thinkers were the rightful heirs to Darwin's evolutionary theory was also a conversation over whether Darwinism could be defended against creationists in the broader cultural context. Gould and others' claims to Darwin shaped the contours of a political, religious and scientific controversy. Copyright © 2014. Published by Elsevier Ltd.

  5. Extinction rates in tumour public goods games.

    Science.gov (United States)

    Gerlee, Philip; Altrock, Philipp M

    2017-09-01

    Cancer evolution and progression are shaped by cellular interactions and Darwinian selection. Evolutionary game theory incorporates both of these principles, and has been proposed as a framework to understand tumour cell population dynamics. A cornerstone of evolutionary dynamics is the replicator equation, which describes changes in the relative abundance of different cell types, and is able to predict evolutionary equilibria. Typically, the replicator equation focuses on differences in relative fitness. We here show that this framework might not be sufficient under all circumstances, as it neglects important aspects of population growth. Standard replicator dynamics might miss critical differences in the time it takes to reach an equilibrium, as this time also depends on cellular turnover in growing but bounded populations. As the system reaches a stable manifold, the time to reach equilibrium depends on cellular death and birth rates. These rates shape the time scales, in particular, in coevolutionary dynamics of growth factor producers and free-riders. Replicator dynamics might be an appropriate framework only when birth and death rates are of similar magnitude. Otherwise, population growth effects cannot be neglected when predicting the time to reach an equilibrium, and cell-type-specific rates have to be accounted for explicitly. © 2017 The Authors.

  6. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Individuals and groups in evolution: Darwinian pluralism and the multilevel ... here is an updated review of the long-standing `kin selection vs group selection' debate. ... The latter is now evidently a pattern among others within a more general ...

  7. Predictive modeling of multicellular structure formation by using Cellular Particle Dynamics simulations

    Science.gov (United States)

    McCune, Matthew; Shafiee, Ashkan; Forgacs, Gabor; Kosztin, Ioan

    2014-03-01

    Cellular Particle Dynamics (CPD) is an effective computational method for describing and predicting the time evolution of biomechanical relaxation processes of multicellular systems. A typical example is the fusion of spheroidal bioink particles during post bioprinting structure formation. In CPD cells are modeled as an ensemble of cellular particles (CPs) that interact via short-range contact interactions, characterized by an attractive (adhesive interaction) and a repulsive (excluded volume interaction) component. The time evolution of the spatial conformation of the multicellular system is determined by following the trajectories of all CPs through integration of their equations of motion. CPD was successfully applied to describe and predict the fusion of 3D tissue construct involving identical spherical aggregates. Here, we demonstrate that CPD can also predict tissue formation involving uneven spherical aggregates whose volumes decrease during the fusion process. Work supported by NSF [PHY-0957914]. Computer time provided by the University of Missouri Bioinformatics Consortium.

  8. Interpreting South African cultural clashes through Darwinian eyes ...

    African Journals Online (AJOL)

    ... an acceptance of what would soon be known as Afrikaans culture as no less worthy and civilised than that of the British and for the application of a radically adapted version of social Darwinism to conflicts between white and black South Africans. Key words: Balmforth, Darwin, Darwinism, eugenics, evolution, Kant, social

  9. Growth and setting of gas bubbles in a viscoelastic matrix imaged by X-ray microtomography: the evolution of cellular structures in fermenting wheat flour dough.

    Science.gov (United States)

    Turbin-Orger, A; Babin, P; Boller, E; Chaunier, L; Chiron, H; Della Valle, G; Dendievel, R; Réguerre, A L; Salvo, L

    2015-05-07

    X-ray tomography is a relevant technique for the dynamic follow-up of gas bubbles in an opaque viscoelastic matrix, especially using image analysis. It has been applied here to pieces of fermenting wheat flour dough of various compositions, at two different voxel sizes (15 and 5 μm). The resulting evolution of the main cellular features shows that the creation of cellular structures follows two regimes that are defined by a characteristic time of connectivity, tc [30 and 80 min]: first (t ≤ tc), bubbles grow freely and then (t ≥ tc) they become connected since the percolation of the gas phase is limited by liquid films. During the first regime, bubbles can be tracked and the local strain rate can be measured. Its values (10(-4)-5 × 10(-4) s(-1)) are in agreement with those computed from dough viscosity and internal gas pressure, both of which depend on the composition. For higher porosity, P = 0.64 in our case, and thus occurring in the second regime, different cellular structures are obtained and XRT images show deformed gas cells that display complex shapes. The comparison of these images with confocal laser scanning microscopy images suggests the presence of liquid films that separate these cells. The dough can therefore be seen as a three-phase medium: viscoelastic matrix/gas cell/liquid phase. The contributions of the different levels of matter organization can be integrated by defining a capillary number (C = 0.1-1) that makes it possible to predict the macroscopic dough behavior.

  10. Vascular measurements correlate with estrogen receptor status

    International Nuclear Information System (INIS)

    Lloyd, Mark C; Alfarouk, Khalid O; Verduzco, Daniel; Bui, Marilyn M; Gillies, Robert J; Ibrahim, Muntaser E; Brown, Joel S; Gatenby, Robert A

    2014-01-01

    Breast carcinoma can be classified as either Estrogen Receptor (ER) positive or negative by immunohistochemical phenotyping, although ER expression may vary from 1 to 100% of malignant cells within an ER + tumor. This is similar to genetic variability observed in other tumor types and is generally viewed as a consequence of intratumoral evolution driven by random genetic mutations. Here we view cellular evolution within tumors as a classical Darwinian system in which variations in molecular properties represent predictable adaptations to spatially heterogeneous environmental selection forces. We hypothesize that ER expression is a successful adaptive strategy only if estrogen is present in the microenvironment. Since the dominant source of estrogen is blood flow, we hypothesized that, in general, intratumoral regions with higher blood flow would contain larger numbers of ER + cells when compared to areas of low blood flow and in turn necrosis. This study used digital pathology whole slide image acquisition and advanced image analysis algorithms. We examined the spatial distribution of ER + and ER- cells, vascular density, vessel area, and tissue necrosis within histological sections of 24 breast cancer specimens. These data were correlated with the patients ER status and molecular pathology report findings. ANOVA analyses revealed a strong correlation between vascular area and ER expression and between high fractional necrosis and absent ER expression (R 2 = 39%; p < 0.003 and R 2 = 46%; p < 0.001), respectively). ER expression did not correlate with tumor grade or size. We conclude that ER expression can be understood as a Darwinian process and linked to variations in estrogen delivery by temporal and spatial heterogeneity in blood flow. This correlation suggests strategies to promote intratumoral blood flow or a cyclic introduction of estrogen in the treatment schedule could be explored as a counter-intuitive approach to increase the efficacy of anti

  11. Predicting cellular growth from gene expression signatures.

    Directory of Open Access Journals (Sweden)

    Edoardo M Airoldi

    2009-01-01

    Full Text Available Maintaining balanced growth in a changing environment is a fundamental systems-level challenge for cellular physiology, particularly in microorganisms. While the complete set of regulatory and functional pathways supporting growth and cellular proliferation are not yet known, portions of them are well understood. In particular, cellular proliferation is governed by mechanisms that are highly conserved from unicellular to multicellular organisms, and the disruption of these processes in metazoans is a major factor in the development of cancer. In this paper, we develop statistical methodology to identify quantitative aspects of the regulatory mechanisms underlying cellular proliferation in Saccharomyces cerevisiae. We find that the expression levels of a small set of genes can be exploited to predict the instantaneous growth rate of any cellular culture with high accuracy. The predictions obtained in this fashion are robust to changing biological conditions, experimental methods, and technological platforms. The proposed model is also effective in predicting growth rates for the related yeast Saccharomyces bayanus and the highly diverged yeast Schizosaccharomyces pombe, suggesting that the underlying regulatory signature is conserved across a wide range of unicellular evolution. We investigate the biological significance of the gene expression signature that the predictions are based upon from multiple perspectives: by perturbing the regulatory network through the Ras/PKA pathway, observing strong upregulation of growth rate even in the absence of appropriate nutrients, and discovering putative transcription factor binding sites, observing enrichment in growth-correlated genes. More broadly, the proposed methodology enables biological insights about growth at an instantaneous time scale, inaccessible by direct experimental methods. Data and tools enabling others to apply our methods are available at http://function.princeton.edu/growthrate.

  12. Formation of cellular films consisting of wurtzite-type zinc oxide nanosheets by mediation of phosphate anions

    International Nuclear Information System (INIS)

    Yamabi, Satoshi; Yahiro, Junko; Iwai, Satoko; Imai, Hiroaki

    2005-01-01

    We successfully prepared a wide variety of wurtzite-type zinc oxide films exhibiting columnar, cellular and densely packed morphologies in a simple aqueous solution system containing phosphate anions. As the phosphate concentration increased, the shape of crystalline units composing the films varied from hexagonal needles into seaweed-like sheets. A novel type of open cellular structures was obtained by assembly of nanoscale zinc oxide sheets covered with phosphate. Specific adsorption of phosphate anions on (001) of the wurtzite-type crystal flattened the crystal grains, and then induced the structural evolution into a cellular form. A blue shift of the absorption edge suggested that the quantum size effect occurred in the nanoscale platy crystals composing the cellular films

  13. Variation in decision making

    NARCIS (Netherlands)

    Dall, Sasha R. X.; Gosling, Samuel; Gordon D.A., Brown,; Dingemanse, Niels; Ido, Erev,; Martin, Kocher,; Laura, Schulz,; Todd, Peter M; Weissing, Franz; Wolf, Max; Hammerstein, Peter; Stevens, Jeffrey R.

    2012-01-01

    Variation in how organisms allocate their behavior over their lifetimes is key to determining Darwinian fitness., and thus the evolution of human and nonhuman decision making. This chapter explores how decision making varies across biologically and societally significant scales and what role such

  14. Selectionist and evolutionary approaches to brain function: a critical appraisal

    Directory of Open Access Journals (Sweden)

    Chrisantha Thomas Fernando

    2012-04-01

    Full Text Available We consider approaches to brain dynamics and function that have been claimed to be Darwinian. These include Edelman’s theory of neuronal group selection, Changeux’s theory of synaptic selection and selective stabilization of pre-representations, Seung’s Darwinian synapse, Loewenstein’s synaptic melioration, Adam’s selfish synapse and Calvin’s replicating activity patterns. Except for the last two, the proposed mechanisms are selectionist but not truly Darwinian, because no replicators with information transfer to copies and hereditary variation can be identified in them. All of them fit, however, a generalized selectionist framework conforming to the picture of Price’s covariance formulation, which deliberately was not specific even to selection in biology, and therefore does not imply an algorithmic picture of biological evolution. Bayesian models and reinforcement learning are formally in agreement with selection dynamics. A classification of search algorithms is shown to include Darwinian replicators (evolutionary units with multiplication, heredity and variability as the most powerful mechanism in a sparsely occupied search space. Examples of why parallel competitive search with information transfer among the units is efficient are given. Finally, we review our recent attempts to construct and analyze simple models of true Darwinian evolutionary units in the brain in terms of connectivity and activity copying of neuronal groups. Although none of the proposed neuronal replicators include miraculous mechanisms, their identification remains a challenge but also a great promise.

  15. Chimeric antigen receptor engineering: a right step in the evolution of adoptive cellular immunotherapy.

    Science.gov (United States)

    Figueroa, Jose A; Reidy, Adair; Mirandola, Leonardo; Trotter, Kayley; Suvorava, Natallia; Figueroa, Alejandro; Konala, Venu; Aulakh, Amardeep; Littlefield, Lauren; Grizzi, Fabio; Rahman, Rakhshanda Layeequr; Jenkins, Marjorie R; Musgrove, Breeanna; Radhi, Saba; D'Cunha, Nicholas; D'Cunha, Luke N; Hermonat, Paul L; Cobos, Everardo; Chiriva-Internati, Maurizio

    2015-03-01

    Cancer immunotherapy comprises different therapeutic strategies that exploit the use of distinct components of the immune system, with the common goal of specifically targeting and eradicating neoplastic cells. These varied approaches include the use of specific monoclonal antibodies, checkpoint inhibitors, cytokines, therapeutic cancer vaccines and cellular anticancer strategies such as activated dendritic cell (DC) vaccines, tumor-infiltrating lymphocytes (TILs) and, more recently, genetically engineered T cells. Each one of these approaches has demonstrated promise, but their generalized success has been hindered by the paucity of specific tumor targets resulting in suboptimal tumor responses and unpredictable toxicities. This review will concentrate on recent advances on the use of engineered T cells for adoptive cellular immunotherapy (ACI) in cancer.

  16. Cellular Stress to Low Gamma-ray Dose

    International Nuclear Information System (INIS)

    Manzanares-Acuna, E.; Vega-Carrillo, H. R.; Letechipia de Leon, C.; Guzman Enriquez, L. J.; Garcia-Talavera, M.

    2004-01-01

    The purpose of this study was to evaluate the effect of low gamma ray intensity upon Hsp 70 expression in human lymphocytes. the heat shock proteins (Hsp) family, are a group of proteins present in all living organism, therefore there are highly conserved and are related to adaptation and evolution. At cellular level these proteins acts as chaperones correcting denatured proteins. when a stress agent, such heavy metals, UV, heat, etc. is affecting a cell a response to this aggression is triggered through overexpression of Hsp. Several studies has been carried out in which the cellular effect are observed, mostly of these studies uses large doses, but very few studies are related with low doses. Blood of healthy volunteers was obtained and the lymphocytes were isolated by ficoll-histopaque gradient. Experimental lots were irradiated in a ''137Cs gamma-ray. Hsp70 expression was found since 0.5 cGy, indicating a threshold to very low doses of gamma rays. (Author) 27 refs

  17. A comparative cellular and molecular biology of longevity database.

    Science.gov (United States)

    Stuart, Jeffrey A; Liang, Ping; Luo, Xuemei; Page, Melissa M; Gallagher, Emily J; Christoff, Casey A; Robb, Ellen L

    2013-10-01

    Discovering key cellular and molecular traits that promote longevity is a major goal of aging and longevity research. One experimental strategy is to determine which traits have been selected during the evolution of longevity in naturally long-lived animal species. This comparative approach has been applied to lifespan research for nearly four decades, yielding hundreds of datasets describing aspects of cell and molecular biology hypothesized to relate to animal longevity. Here, we introduce a Comparative Cellular and Molecular Biology of Longevity Database, available at ( http://genomics.brocku.ca/ccmbl/ ), as a compendium of comparative cell and molecular data presented in the context of longevity. This open access database will facilitate the meta-analysis of amalgamated datasets using standardized maximum lifespan (MLSP) data (from AnAge). The first edition contains over 800 data records describing experimental measurements of cellular stress resistance, reactive oxygen species metabolism, membrane composition, protein homeostasis, and genome homeostasis as they relate to vertebrate species MLSP. The purpose of this review is to introduce the database and briefly demonstrate its use in the meta-analysis of combined datasets.

  18. The pre-Mendelian, pre-Darwinian world: Shifting relations between ...

    Indian Academy of Sciences (India)

    Unknown

    Although imprinting and paramutation confound Men- delian patterns .... (Darwin 1872) in response to arguments of his critics, such as ... existed, could move things forward. Assume .... theory for evolution in action, appears to depend (at least.

  19. The Emergence of Multi-Cellular Robot Organisms through On-line On-board Evolution

    NARCIS (Netherlands)

    Weel, B.P.M.; Haasdijk, E.W.; Eiben, A.E.

    2012-01-01

    We investigate whether a swarm of robots can evolve controllers that cause aggregation into 'multi-cellular' robot organisms without a specific reward to do so. To this end, we create a world where aggregated robots receive more energy than individual ones and enable robots to evolve their

  20. Darwinian algorithms and the Wason selection task: a factorial analysis of social contract selection task problems.

    Science.gov (United States)

    Platt, R D; Griggs, R A

    1993-08-01

    In four experiments with 760 subjects, the present study examined Cosmides' Darwinian algorithm theory of reasoning: specifically, its explanation of facilitation on the Wason selection task. The first experiment replicated Cosmides' finding of facilitation for social contract versions of the selection task, using both her multiple-problem format and a single-problem format. Experiment 2 examined performance on Cosmides' three main social contract problems while manipulating the perspective of the subject and the presence and absence of cost-benefit information. The presence of cost-benefit information improved performance in two of the three problems while the perspective manipulation had no effect. In Experiment 3, the cost-benefit effect was replicated; and performance on one of the three problems was enhanced by the presence of explicit negatives on the NOT-P and NOT-Q cards. Experiment 4 examined the role of the deontic term "must" in the facilitation observed for two of the social contract problems. The presence of "must" led to a significant improvement in performance. The results of these experiments are strongly supportive of social contract theory in that cost-benefit information is necessary for substantial facilitation to be observed in Cosmides' problems. These findings also suggest the presence of other cues that can help guide subjects to a deontic social contract interpretation when the social contract nature of the problem is not clear.

  1. Ripensare Darwin? Di ex‐aptations e neotenie. E di Topolino, Pippo e simpatiche salamandre messicane

    Directory of Open Access Journals (Sweden)

    AMODIO, PAOLO

    2016-12-01

    Full Text Available Rethinking Darwin? About Ex‐aptations and Neotenies. Concerning Mickey Mouse, Goofy and likeable mexican Salamanders The theory of evolution by natural selection of Charles Darwin, whose first general exposure dates back to 1859, with the publication of the Origin of Species, is still a matter of intense debate among natural sciences’ scholars and philosophers. After the merger of Darwinian evolutionary research program with the theory of heredity of Gregor Mendel, the mathematical form of population genetics and the analysis of paleontological data (Modern Synthesis and the the important contributions of post-Darwinian authors such as S.J. Gould and N. Eldredge we are entering a new era of great discoveries and news. On the one hand, new data from genetics and paleoanthropology, on the other hand the impetuous development of some fields of applied science such as nanobiotechnology, genetic engineering and synthetic biology put us into the need and the urgency to underline, once again, the relevance and the extraordinary heuristic power of Darwinian research program, an even greater urgency since some authors have announced that we would be at a time to access a post-Darwinian and post-evolutionary era in which man as we actually know it is about to disappear.

  2. Research traditions and evolutionary explanations in medicine.

    Science.gov (United States)

    Méthot, Pierre-Olivier

    2011-02-01

    In this article, I argue that distinguishing 'evolutionary' from 'Darwinian' medicine will help us assess the variety of roles that evolutionary explanations can play in a number of medical contexts. Because the boundaries of evolutionary and Darwinian medicine overlap to some extent, however, they are best described as distinct 'research traditions' rather than as competing paradigms. But while evolutionary medicine does not stand out as a new scientific field of its own, Darwinian medicine is united by a number of distinctive theoretical and methodological claims. For example, evolutionary medicine and Darwinian medicine can be distinguished with respect to the styles of evolutionary explanations they employ. While the former primarily involves 'forward looking' explanations, the latter depends mostly on 'backward looking' explanations. A forward looking explanation tries to predict the effects of ongoing evolutionary processes on human health and disease in contemporary environments (e.g., hospitals). In contrast, a backward looking explanation typically applies evolutionary principles from the vantage point of humans' distant biological past in order to assess present states of health and disease. Both approaches, however, are concerned with the prevention and control of human diseases. In conclusion, I raise some concerns about the claim that 'nothing in medicine makes sense except in the light of evolution'.

  3. [Stress-induced cellular adaptive mutagenesis].

    Science.gov (United States)

    Zhu, Linjiang; Li, Qi

    2014-04-01

    The adaptive mutations exist widely in the evolution of cells, such as antibiotic resistance mutations of pathogenic bacteria, adaptive evolution of industrial strains, and cancerization of human somatic cells. However, how these adaptive mutations are generated is still controversial. Based on the mutational analysis models under the nonlethal selection conditions, stress-induced cellular adaptive mutagenesis is proposed as a new evolutionary viewpoint. The hypothetic pathway of stress-induced mutagenesis involves several intracellular physiological responses, including DNA damages caused by accumulation of intracellular toxic chemicals, limitation of DNA MMR (mismatch repair) activity, upregulation of general stress response and activation of SOS response. These responses directly affect the accuracy of DNA replication from a high-fidelity manner to an error-prone one. The state changes of cell physiology significantly increase intracellular mutation rate and recombination activity. In addition, gene transcription under stress condition increases the instability of genome in response to DNA damage, resulting in transcription-associated DNA mutagenesis. In this review, we summarize these two molecular mechanisms of stress-induced mutagenesis and transcription-associated DNA mutagenesis to help better understand the mechanisms of adaptive mutagenesis.

  4. Formal Definitions of Unbounded Evolution and Innovation Reveal Universal Mechanisms for Open-Ended Evolution in Dynamical Systems.

    Science.gov (United States)

    Adams, Alyssa; Zenil, Hector; Davies, Paul C W; Walker, Sara Imari

    2017-04-20

    Open-ended evolution (OEE) is relevant to a variety of biological, artificial and technological systems, but has been challenging to reproduce in silico. Most theoretical efforts focus on key aspects of open-ended evolution as it appears in biology. We recast the problem as a more general one in dynamical systems theory, providing simple criteria for open-ended evolution based on two hallmark features: unbounded evolution and innovation. We define unbounded evolution as patterns that are non-repeating within the expected Poincare recurrence time of an isolated system, and innovation as trajectories not observed in isolated systems. As a case study, we implement novel variants of cellular automata (CA) where the update rules are allowed to vary with time in three alternative ways. Each is capable of generating conditions for open-ended evolution, but vary in their ability to do so. We find that state-dependent dynamics, regarded as a hallmark of life, statistically out-performs other candidate mechanisms, and is the only mechanism to produce open-ended evolution in a scalable manner, essential to the notion of ongoing evolution. This analysis suggests a new framework for unifying mechanisms for generating OEE with features distinctive to life and its artifacts, with broad applicability to biological and artificial systems.

  5. Darwinian sex roles confirmed across the animal kingdom

    OpenAIRE

    Janicke Tim; Häderer Ines; Lajeunesse Marc J; Anthes Nils

    2016-01-01

    Since Darwin?s conception of sexual selection theory, scientists have struggled to identify the evolutionary forces underlying the pervasive differences between male and female behavior, morphology, and physiology. The Darwin-Bateman paradigm predicts that anisogamy imposes stronger sexual selection on males, which, in turn, drives the evolution of conventional sex roles in terms of female-biased parental care and male-biased sexual dimorphism. Although this paradigm forms the cornerstone of ...

  6. Senescence gives insights into the morphogenetic evolution of anamniotes

    Directory of Open Access Journals (Sweden)

    Éric Villiard

    2017-06-01

    Full Text Available Senescence represents a mechanism to avoid undesired cell proliferation that plays a role in tumor suppression, wound healing and embryonic development. In order to gain insight on the evolution of senescence, we looked at its presence in developing axolotls (urodele amphibians and in zebrafish (teleost fish, which are both anamniotes. Our data indicate that cellular senescence is present in various developing structures in axolotls (pronephros, olfactory epithelium of nerve fascicles, lateral organs, gums and in zebrafish (epithelium of the yolk sac and in the lower part of the gut. Senescence was particularly associated with transient structures (pronephros in axolotls and yolk sac in zebrafish suggesting that it may play a role in the elimination of these tissues. Our data supports the notion that cellular senescence evolved early in vertebrate evolution to influence embryonic development.

  7. Influences of Teleological and Lamarckian Thinking on Student Understanding of Natural Selection

    Science.gov (United States)

    Stover, Shawn K.; Mabry, Michelle L.

    2007-01-01

    Previous research has demonstrated creationist, Lamarckian, and teleological reasoning in high school and college students. These lines of thinking conflict with the Darwinian notion of natural selection, which serves as the primary catalyst for biological evolution. The current study assessed evolutionary conceptions in non-science majors,…

  8. Investigation of high burnup structures in uranium dioxide applying cellular automata: algorithms and codes

    International Nuclear Information System (INIS)

    Akishina, E.P.; Kostenko, B.F.; Ivanov, V.V.

    2003-01-01

    A new method of research in spatial structures that result from uranium dioxide burning in nuclear reactors of modern atomic plants is suggested. The method is based on the presentation of images of the mentioned structures in the form of the working field of a cellular automaton (CA). First, it has allowed one to extract some important quantitative characteristics of the structures directly from the micrographs of the uranium fuel surface. Secondly, the CA has been found out to allow one to formulate easily the dynamics of the evolution of the studied structures in terms of such micrograph elements as spots, spots' boundaries, cracks, etc. Relation has been found between the dynamics and some exactly solvable models of the theory of cellular automata, in particular, the Ising model and the vote model. This investigation gives a detailed description of some CA algorithms which allow one to perform the fuel surface image processing and to model its evolution caused by burnup or chemical etching. (author)

  9. Toward an evolutionary-predictive foundation for creativity : Commentary on "Human creativity, evolutionary algorithms, and predictive representations: The mechanics of thought trials" by Arne Dietrich and Hilde Haider, 2014 (Accepted pending minor revisions for publication in Psychonomic Bulletin & Review).

    Science.gov (United States)

    Gabora, Liane; Kauffman, Stuart

    2016-04-01

    Dietrich and Haider (Psychonomic Bulletin & Review, 21 (5), 897-915, 2014) justify their integrative framework for creativity founded on evolutionary theory and prediction research on the grounds that "theories and approaches guiding empirical research on creativity have not been supported by the neuroimaging evidence." Although this justification is controversial, the general direction holds promise. This commentary clarifies points of disagreement and unresolved issues, and addresses mis-applications of evolutionary theory that lead the authors to adopt a Darwinian (versus Lamarckian) approach. To say that creativity is Darwinian is not to say that it consists of variation plus selection - in the everyday sense of the term - as the authors imply; it is to say that evolution is occurring because selection is affecting the distribution of randomly generated heritable variation across generations. In creative thought the distribution of variants is not key, i.e., one is not inclined toward idea A because 60 % of one's candidate ideas are variants of A while only 40 % are variants of B; one is inclined toward whichever seems best. The authors concede that creative variation is partly directed; however, the greater the extent to which variants are generated non-randomly, the greater the extent to which the distribution of variants can reflect not selection but the initial generation bias. Since each thought in a creative process can alter the selective criteria against which the next is evaluated, there is no demarcation into generations as assumed in a Darwinian model. We address the authors' claim that reduced variability and individuality are more characteristic of Lamarckism than Darwinian evolution, and note that a Lamarckian approach to creativity has addressed the challenge of modeling the emergent features associated with insight.

  10. Evolution of sexual asymmetry

    Directory of Open Access Journals (Sweden)

    Hoekstra Rolf F

    2004-09-01

    Full Text Available Abstract Background The clear dominance of two-gender sex in recent species is a notorious puzzle of evolutionary theory. It has at least two layers: besides the most fundamental and challenging question why sex exists at all, the other part of the problem is equally perplexing but much less studied. Why do most sexual organisms use a binary mating system? Even if sex confers an evolutionary advantage (through whatever genetic mechanism, why does it manifest that advantage in two, and exactly two, genders (or mating types? Why not just one, and why not more than two? Results Assuming that sex carries an inherent fitness advantage over pure clonal multiplication, we attempt to give a feasible solution to the problem of the evolution of dimorphic sexual asymmetry as opposed to monomorphic symmetry by using a spatial (cellular automaton model and its non-spatial (mean-field approximation. Based on a comparison of the spatial model to the mean-field approximation we suggest that spatial population structure must have played a significant role in the evolution of mating types, due to the largely clonal (self-aggregated spatial distribution of gamete types, which is plausible in aquatic habitats for physical reasons, and appears to facilitate the evolution of a binary mating system. Conclusions Under broad ecological and genetic conditions the cellular automaton predicts selective removal from the population of supposedly primitive gametes that are able to mate with their own type, whereas the non-spatial model admits coexistence of the primitive type and the mating types. Thus we offer a basically ecological solution to a theoretical problem that earlier models based on random gamete encounters had failed to resolve.

  11. Self-organisation in Cellular Automata with Coalescent Particles: Qualitative and Quantitative Approaches

    Science.gov (United States)

    Hellouin de Menibus, Benjamin; Sablik, Mathieu

    2017-06-01

    This article introduces new tools to study self-organisation in a family of simple cellular automata which contain some particle-like objects with good collision properties (coalescence) in their time evolution. We draw an initial configuration at random according to some initial shift-ergodic measure, and use the limit measure to describe the asymptotic behaviour of the automata. We first take a qualitative approach, i.e. we obtain information on the limit measure(s). We prove that only particles moving in one particular direction can persist asymptotically. This provides some previously unknown information on the limit measures of various deterministic and probabilistic cellular automata: 3 and 4-cyclic cellular automata [introduced by Fisch (J Theor Probab 3(2):311-338, 1990; Phys D 45(1-3):19-25, 1990)], one-sided captive cellular automata [introduced by Theyssier (Captive Cellular Automata, 2004)], the majority-traffic cellular automaton, a self stabilisation process towards a discrete line [introduced by Regnault and Rémila (in: Mathematical Foundations of Computer Science 2015—40th International Symposium, MFCS 2015, Milan, Italy, Proceedings, Part I, 2015)]. In a second time we restrict our study to a subclass, the gliders cellular automata. For this class we show quantitative results, consisting in the asymptotic law of some parameters: the entry times [generalising K ůrka et al. (in: Proceedings of AUTOMATA, 2011)], the density of particles and the rate of convergence to the limit measure.

  12. Receptor Oligomerization as a Process Modulating Cellular Semiotics

    DEFF Research Database (Denmark)

    Giorgi, Franco; Bruni, Luis Emilio; Maggio, Roberto

    2010-01-01

    be another level of quality control that may help maintaining GPCRs rather stable throughout evolution. We propose here receptor oligomerization to be a basic molecular mechanism controlling GPCRs redundancy in many different cell types, and the plasma membrane as the first hierarchical cell structure...... at which selective categorical sensing may occur. Categorical sensing can be seen as the cellular capacity for identifying and ordering complex patterns of mixed signals out of a contextual matrix, i.e., the recognition of meaningful patterns out of ubiquitous signals. In this context, redundancy...

  13. Selection of doublet cellular patterns in directional solidification through spatially periodic perturbations

    International Nuclear Information System (INIS)

    Losert, W.; Stillman, D.A.; Cummins, H.Z.; Kopczynski, P.; Rappel, W.; Karma, A.

    1998-01-01

    Pattern formation at the solid-liquid interface of a growing crystal was studied in directional solidification using a perturbation technique. We analyzed both experimentally and numerically the stability range and dynamical selection of cellular arrays of 'doublets' with asymmetric tip shapes, separated by alternate deep and shallow grooves. Applying an initial periodic perturbation of arbitrary wavelength to the unstable planar interface allowed us to force the interface to evolve into doublet states that would not otherwise be dynamically accessible from a planar interface. We determined systematically the ranges of wavelength corresponding to stable singlets, stable doublets, and transient unstable patterns. Experimentally, this was accomplished by applying a brief UV light pulse of a desired spatial periodicity to the planar interface during the planar-cellular transient using the model alloy Succinonitrile-Coumarin 152. Numerical simulations of the nonlinear evolution of the interface were performed starting from a small sinusoidal perturbation of the steady-state planar interface. These simulations were carried out using a computationally efficient phase-field symmetric model of directional solidification with recently reformulated asymptotics and vanishing kinetics [A. Karma and W.-J. Rappel, Phys. Rev. E 53 R3017 (1996); Phys. Rev. Lett. 77, 4050 (1996); Phys. Rev. E 57, 4323 (1998)], which allowed us to simulate spatially extended arrays that can be meaningfully compared to experiments. Simulations and experiments show remarkable qualitative agreement in the dynamic evolution, steady-state structure, and instability mechanisms of doublet cellular arrays. copyright 1998 The American Physical Society

  14. Discrete dynamic modeling of cellular signaling networks.

    Science.gov (United States)

    Albert, Réka; Wang, Rui-Sheng

    2009-01-01

    Understanding signal transduction in cellular systems is a central issue in systems biology. Numerous experiments from different laboratories generate an abundance of individual components and causal interactions mediating environmental and developmental signals. However, for many signal transduction systems there is insufficient information on the overall structure and the molecular mechanisms involved in the signaling network. Moreover, lack of kinetic and temporal information makes it difficult to construct quantitative models of signal transduction pathways. Discrete dynamic modeling, combined with network analysis, provides an effective way to integrate fragmentary knowledge of regulatory interactions into a predictive mathematical model which is able to describe the time evolution of the system without the requirement for kinetic parameters. This chapter introduces the fundamental concepts of discrete dynamic modeling, particularly focusing on Boolean dynamic models. We describe this method step-by-step in the context of cellular signaling networks. Several variants of Boolean dynamic models including threshold Boolean networks and piecewise linear systems are also covered, followed by two examples of successful application of discrete dynamic modeling in cell biology.

  15. Multiscale evaluation of cellular adhesion alteration and cytoskeleton remodeling by magnetic bead twisting.

    Science.gov (United States)

    Isabey, Daniel; Pelle, Gabriel; André Dias, Sofia; Bottier, Mathieu; Nguyen, Ngoc-Minh; Filoche, Marcel; Louis, Bruno

    2016-08-01

    Cellular adhesion forces depend on local biological conditions meaning that adhesion characterization must be performed while preserving cellular integrity. We presently postulate that magnetic bead twisting provides an appropriate stress, i.e., basically a clamp, for assessment in living cells of both cellular adhesion and mechanical properties of the cytoskeleton. A global dissociation rate obeying a Bell-type model was used to determine the natural dissociation rate ([Formula: see text]) and a reference stress ([Formula: see text]). These adhesion parameters were determined in parallel to the mechanical properties for a variety of biological conditions in which either adhesion or cytoskeleton was selectively weakened or strengthened by changing successively ligand concentration, actin polymerization level (by treating with cytochalasin D), level of exerted stress (by increasing magnetic torque), and cell environment (by using rigid and soft 3D matrices). On the whole, this multiscale evaluation of the cellular and molecular responses to a controlled stress reveals an evolution which is consistent with stochastic multiple bond theories and with literature results obtained with other molecular techniques. Present results confirm the validity of the proposed bead-twisting approach for its capability to probe cellular and molecular responses in a variety of biological conditions.

  16. Internal Disequilibria and Phenotypic Diversification during Replication of Hepatitis C Virus in a Noncoevolving Cellular Environment.

    Science.gov (United States)

    Moreno, Elena; Gallego, Isabel; Gregori, Josep; Lucía-Sanz, Adriana; Soria, María Eugenia; Castro, Victoria; Beach, Nathan M; Manrubia, Susanna; Quer, Josep; Esteban, Juan Ignacio; Rice, Charles M; Gómez, Jordi; Gastaminza, Pablo; Domingo, Esteban; Perales, Celia

    2017-05-15

    Viral quasispecies evolution upon long-term virus replication in a noncoevolving cellular environment raises relevant general issues, such as the attainment of population equilibrium, compliance with the molecular-clock hypothesis, or stability of the phenotypic profile. Here, we evaluate the adaptation, mutant spectrum dynamics, and phenotypic diversification of hepatitis C virus (HCV) in the course of 200 passages in human hepatoma cells in an experimental design that precluded coevolution of the cells with the virus. Adaptation to the cells was evidenced by increase in progeny production. The rate of accumulation of mutations in the genomic consensus sequence deviated slightly from linearity, and mutant spectrum analyses revealed a complex dynamic of mutational waves, which was sustained beyond passage 100. The virus underwent several phenotypic changes, some of which impacted the virus-host relationship, such as enhanced cell killing, a shift toward higher virion density, and increased shutoff of host cell protein synthesis. Fluctuations in progeny production and failure to reach population equilibrium at the genomic level suggest internal instabilities that anticipate an unpredictable HCV evolution in the complex liver environment. IMPORTANCE Long-term virus evolution in an unperturbed cellular environment can reveal features of virus evolution that cannot be explained by comparing natural viral isolates. In the present study, we investigate genetic and phenotypic changes that occur upon prolonged passage of hepatitis C virus (HCV) in human hepatoma cells in an experimental design in which host cell evolutionary change is prevented. Despite replication in a noncoevolving cellular environment, the virus exhibited internal population disequilibria that did not decline with increased adaptation to the host cells. The diversification of phenotypic traits suggests that disequilibria inherent to viral populations may provide a selective advantage to viruses that can

  17. Gene/Environment Interaction in Atherosclerosis: An Example of Clinical Medicine as Seen from the Evolutionary Perspective

    Directory of Open Access Journals (Sweden)

    Gerhard Mertens

    2010-01-01

    The chronic multifactorial disease of atherosclerosis clearly illustrates the Darwinian paradigm. Recent research, combining the effects of genes and environment, has provided surprising clues to the pathogenesis of this major public health problem. This example makes a strong case for recognizing evolution biology as a basic science for medicine.

  18. En de aarde bracht voort : Christelijk geloof en evolutie

    NARCIS (Netherlands)

    van den Brink, G.

    2017-01-01

    If standard neo-Darwinian accounts of the theory of biological evolution are by and large correct, what does this imply for the content of the Christian faith? This book examines six fields of tension in this connection and concludes that some adjustments are needed, esp. in terms of traditional

  19. Cell evolution and Earth history: stasis and revolution.

    Science.gov (United States)

    Cavalier-Smith, Thomas

    2006-06-29

    This synthesis has three main parts. The first discusses the overall tree of life and nature of the last common ancestor (cenancestor). I emphasize key steps in cellular evolution important for ordering and timing the major evolutionary innovations in the history of the biosphere, explaining especially the origins of the eukaryote cell and of bacterial flagella and cell envelope novelties. Second, I map the tree onto the fossil record and discuss dates of key events and their biogeochemical impact. Finally, I present a broad synthesis, discussing evidence for a three-phase history of life. The first phase began perhaps ca 3.5 Gyr ago, when the origin of cells and anoxic photosynthesis generated the arguably most primitive prokaryote phylum, Chlorobacteria (= Chloroflexi), the first negibacteria with cells bounded by two acyl ester phospholipid membranes. After this 'chlorobacterial age' of benthic anaerobic evolution protected from UV radiation by mineral grains, two momentous quantum evolutionary episodes of cellular innovation and microbial radiation dramatically transformed the Earth's surface: the glycobacterial revolution initiated an oxygenic 'age of cyanobacteria' and, as the ozone layer grew, the rise of plankton; immensely later, probably as recently as ca 0.9 Gyr ago, the neomuran revolution ushered in the 'age of eukaryotes', Archaebacteria (arguably the youngest bacterial phylum), and morphological complexity. Diversification of glycobacteria ca 2.8 Gyr ago, predominantly inhabiting stratified benthic mats, I suggest caused serial depletion of 13C by ribulose 1,5-bis-phosphate caboxylase/oxygenase (Rubisco) to yield ultralight late Archaean organic carbon formerly attributed to methanogenesis plus methanotrophy. The late origin of archaebacterial methanogenesis ca 720 Myr ago perhaps triggered snowball Earth episodes by slight global warming increasing weathering and reducing CO2 levels, to yield runaway cooling; the origin of anaerobic methane

  20. New Gene Evolution: Little Did We Know

    Science.gov (United States)

    Long, Manyuan; VanKuren, Nicholas W.; Chen, Sidi; Vibranovski, Maria D.

    2014-01-01

    Genes are perpetually added to and deleted from genomes during evolution. Thus, it is important to understand how new genes are formed and evolve as critical components of the genetic systems determining the biological diversity of life. Two decades of effort have shed light on the process of new gene origination, and have contributed to an emerging comprehensive picture of how new genes are added to genomes, ranging from the mechanisms that generate new gene structures to the presence of new genes in different organisms to the rates and patterns of new gene origination and the roles of new genes in phenotypic evolution. We review each of these aspects of new gene evolution, summarizing the main evidence for the origination and importance of new genes in evolution. We highlight findings showing that new genes rapidly change existing genetic systems that govern various molecular, cellular and phenotypic functions. PMID:24050177

  1. Hindu Responses to Darwinism: Assimilation and Rejection in a Colonial and Post-Colonial Context

    Science.gov (United States)

    Brown, C. Mackenzie

    2010-01-01

    Hindu responses to Darwinism, like Christian, have run the gamut from outright rejection to fairly robust but limited accommodations of the Darwinian perspective. Despite certain features of Hindu thought such as the enormous time-scales of traditional cosmogonies that may suggest considerable affinity with modern notions of organic evolution,…

  2. Cellular modelling of river catchments and reaches: Advantages, limitations and prospects

    Science.gov (United States)

    Coulthard, T. J.; Hicks, D. M.; Van De Wiel, M. J.

    2007-10-01

    The last decade has witnessed the development of a series of cellular models that simulate the processes operating within river channels and drive their geomorphic evolution. Their proliferation can be partly attributed to the relative simplicity of cellular models and their ability to address some of the shortcomings of other numerical models. By using relaxed interpretations of the equations determining fluid flow, cellular models allow rapid solutions of water depths and velocities. These can then be used to drive (usually) conventional sediment transport relations to determine erosion and deposition and alter the channel form. The key advance of using these physically based yet simplified approaches is that they allow us to apply models to a range of spatial scales (1-100 km 2) and time periods (1-100 years) that are especially relevant to contemporary management and fluvial studies. However, these approaches are not without their limitations and technical problems. This paper reviews the findings of nearly 10 years of research into modelling fluvial systems with cellular techniques, principally focusing on improvements in routing water and how fluvial erosion and deposition (including lateral erosion) are represented. These ideas are illustrated using sample simulations of the River Teifi, Wales. A detailed case study is then presented, demonstrating how cellular models can explore the interactions between vegetation and the morphological dynamics of the braided Waitaki River, New Zealand. Finally, difficulties associated with model validation and the problems, prospects and future issues important to the further development and application of these cellular fluvial models are outlined.

  3. United theory of biological evolution: Disaster-forced evolution through Supernova, radioactive ash fall-outs, genome instability, and mass extinctions

    Directory of Open Access Journals (Sweden)

    Toshikazu Ebisuzaki

    2015-01-01

    Full Text Available We present the disaster-forced biological evolution model as a general framework that includes Darwinian “phylogenic gradualism”, Eldredge-Gould's “punctuated equilibrium”, mass extinctions, and allopatric, parapatric, and sympatric speciation. It describes how reproductive isolation of organisms is established through global disasters due to supernova encounters and local disasters due to radioactive volcanic ash fall-outs by continental alkaline volcanism. Our new evolution model uniquely highlights three major factors of disaster-forced speciation: enhanced mutation rate by higher natural radiation level, smaller population size, and shrunken habitat size (i.e., isolation among the individual populations. We developed a mathematical model describing speciation of a half-isolated group from a parental group, taking into account the population size (Ne, immigration rate (m, and mutation rate (μ. The model gives a quantitative estimate of the speciation, which is consistent with the observations of speciation speed. For example, the speciation takes at least 105 generations, if mutation rate is less than 10−3 per generation per individual. This result is consistent with the previous studies, in which μ is assumed to be 10−3–10−5. On the other hand, the speciation is much faster (less than 105 generations for the case that μ is as large as 0.1 in parapatric conditions (m < μ. Even a sympatric (m ~ 1 speciation can occur within 103 generations, if mutation rate is very high (μ ~ 1 mutation per individual per generation, and if Ne < 20–30. Such a high mutation rate is possible during global disasters due to supernova encounters and local disasters due to radioactive ash fall-outs. They raise natural radiation level by a factor of 100–1000. Such rapid speciation events can also contribute to macro-evolution during mass extinction events, such as observed during the Cambrian explosion of biodiversity. A

  4. Comparative analysis of protein coding sequences from human, mouse and the domesticated pig

    DEFF Research Database (Denmark)

    Jørgensen, Frank Grønlund; Hobolth, Asger; Hornshøj, Henrik

    2005-01-01

    Background: The availability of abundant sequence data from key model organisms has made large scale studies of mulecular evolution an exciting possibility. Here we use full length cDNA alignments comprising more than 700,000 nucleotides from human, mouse, pig and the Japanese pufferfish Fugu rub...... rubrices in order to investigate 1) the relationships between three major lineages of mammals: rodents, artiodactys and primates, and 2) the rate of evolution and the occurrence of positive Darwinian selection using codon based models of sequence evolution. Results: We provide evidence...

  5. Cellular Automata on Graphs: Topological Properties of ER Graphs Evolved towards Low-Entropy Dynamics

    Directory of Open Access Journals (Sweden)

    Marc-Thorsten Hütt

    2012-06-01

    Full Text Available Cellular automata (CA are a remarkably  efficient tool for exploring general properties of complex systems and spatiotemporal patterns arising from local rules. Totalistic cellular automata,  where the update  rules depend  only on the density of neighboring states, are at the same time a versatile  tool for exploring  dynamical  processes on graphs. Here we briefly review our previous results on cellular automata on graphs, emphasizing some systematic relationships between network architecture and dynamics identified in this way. We then extend the investigation  towards graphs obtained in a simulated-evolution procedure, starting from Erdő s–Rényi (ER graphs and selecting for low entropies of the CA dynamics. Our key result is a strong association of low Shannon entropies with a broadening of the graph’s degree distribution.

  6. Bone-associated gene evolution and the origin of flight in birds.

    Science.gov (United States)

    Machado, João Paulo; Johnson, Warren E; Gilbert, M Thomas P; Zhang, Guojie; Jarvis, Erich D; O'Brien, Stephen J; Antunes, Agostinho

    2016-05-18

    Bones have been subjected to considerable selective pressure throughout vertebrate evolution, such as occurred during the adaptations associated with the development of powered flight. Powered flight evolved independently in two extant clades of vertebrates, birds and bats. While this trait provided advantages such as in aerial foraging habits, escape from predators or long-distance travels, it also imposed great challenges, namely in the bone structure. We performed comparative genomic analyses of 89 bone-associated genes from 47 avian genomes (including 45 new), 39 mammalian, and 20 reptilian genomes, and demonstrate that birds, after correcting for multiple testing, have an almost two-fold increase in the number of bone-associated genes with evidence of positive selection (~52.8 %) compared with mammals (~30.3 %). Most of the positive-selected genes in birds are linked with bone regulation and remodeling and thirteen have been linked with functional pathways relevant to powered flight, including bone metabolism, bone fusion, muscle development and hyperglycemia levels. Genes encoding proteins involved in bone resorption, such as TPP1, had a high number of sites under Darwinian selection in birds. Patterns of positive selection observed in bird ossification genes suggest that there was a period of intense selective pressure to improve flight efficiency that was closely linked with constraints on body size.

  7. Emergence of life: Physical chemistry changes the paradigm.

    Science.gov (United States)

    Spitzer, Jan; Pielak, Gary J; Poolman, Bert

    2015-06-10

    Origin of life research has been slow to advance not only because of its complex evolutionary nature (Franklin Harold: In Search of Cell History, 2014) but also because of the lack of agreement on fundamental concepts, including the question of 'what is life?'. To re-energize the research and define a new experimental paradigm, we advance four premises to better understand the physicochemical complexities of life's emergence: (1) Chemical and Darwinian (biological) evolutions are distinct, but become continuous with the appearance of heredity. (2) Earth's chemical evolution is driven by energies of cycling (diurnal) disequilibria and by energies of hydrothermal vents. (3) Earth's overall chemical complexity must be high at the origin of life for a subset of (complex) chemicals to phase separate and evolve into living states. (4) Macromolecular crowding in aqueous electrolytes under confined conditions enables evolution of molecular recognition and cellular self-organization. We discuss these premises in relation to current 'constructive' (non-evolutionary) paradigm of origins research - the process of complexification of chemical matter 'from the simple to the complex'. This paradigm artificially avoids planetary chemical complexity and the natural tendency of molecular compositions toward maximum disorder embodied in the second law of thermodynamics. Our four premises suggest an empirical program of experiments involving complex chemical compositions under cycling gradients of temperature, water activity and electromagnetic radiation.

  8. Particles and Patterns in Cellular Automata

    International Nuclear Information System (INIS)

    Jen, E.; Das, R.; Beasley, C.E.

    1999-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Our objective has been to develop tools for studying particle interactions in a class of dynamical systems characterized by discreteness, determinism, local interaction, and an inherently parallel form of evolution. These systems can be described by cellular automata (CA) and the behavior we studied has improved our understanding of the nature of patterns generated by CAs, their ability to perform global computations, and their relationship to continuous dynamical systems. We have also developed a rule-table mathematics that enables one to custom-design CA rule tables to generate patterns of specified types, or to perform specified computational tasks

  9. Stochastic resonance and the evolution of Daphnia foraging strategy

    International Nuclear Information System (INIS)

    Dees, Nathan D; Bahar, Sonya; Moss, Frank

    2008-01-01

    Search strategies are currently of great interest, with reports on foraging ranging from albatrosses and spider monkeys to microzooplankton. Here, we investigate the role of noise in optimizing search strategies. We focus on the zooplankton Daphnia, which move in successive sequences consisting of a hop, a pause and a turn through an angle. Recent experiments have shown that their turning angle distributions (TADs) and underlying noise intensities are similar across species and age groups, suggesting an evolutionary origin of this internal noise. We explore this hypothesis further with a digital simulation (EVO) based solely on the three central Darwinian themes: inheritability, variability and survivability. Separate simulations utilizing stochastic resonance (SR) indicate that foraging success, and hence fitness, is maximized at an optimum TAD noise intensity, which is represented by the distribution's characteristic width, σ. In both the EVO and SR simulations, foraging success is the criterion, and the results are the predicted characteristic widths of the TADs that maximize success. Our results are twofold: (1) the evolving characteristic widths achieve stasis after many generations; (2) as a hop length parameter is changed, variations in the evolved widths generated by EVO parallel those predicted by SR. These findings provide support for the hypotheses that (1) σ is an evolved quantity and that (2) SR plays a role in evolution. (communication)

  10. Colloquium paper: uniquely human evolution of sialic acid genetics and biology.

    Science.gov (United States)

    Varki, Ajit

    2010-05-11

    Darwinian evolution of humans from our common ancestors with nonhuman primates involved many gene-environment interactions at the population level, and the resulting human-specific genetic changes must contribute to the "Human Condition." Recent data indicate that the biology of sialic acids (which directly involves less than 60 genes) shows more than 10 uniquely human genetic changes in comparison with our closest evolutionary relatives. Known outcomes are tissue-specific changes in abundant cell-surface glycans, changes in specificity and/or expression of multiple proteins that recognize these glycans, and novel pathogen regimes. Specific events include Alu-mediated inactivation of the CMAH gene, resulting in loss of synthesis of the Sia N-glycolylneuraminic acid (Neu5Gc) and increase in expression of the precursor N-acetylneuraminic acid (Neu5Ac); increased expression of alpha2-6-linked Sias (likely because of changed expression of ST6GALI); and multiple changes in SIGLEC genes encoding Sia-recognizing Ig-like lectins (Siglecs). The last includes binding specificity changes (in Siglecs -5, -7, -9, -11, and -12); expression pattern changes (in Siglecs -1, -5, -6, and -11); gene conversion (SIGLEC11); and deletion or pseudogenization (SIGLEC13, SIGLEC14, and SIGLEC16). A nongenetic outcome of the CMAH mutation is human metabolic incorporation of foreign dietary Neu5Gc, in the face of circulating anti-Neu5Gc antibodies, generating a novel "xeno-auto-antigen" situation. Taken together, these data suggest that both the genes associated with Sia biology and the related impacts of the environment comprise a relative "hot spot" of genetic and physiological changes in human evolution, with implications for uniquely human features both in health and disease.

  11. Birds Do It, Bees Do It: Evolution and the Comparative Psychology of Mate Choice

    Science.gov (United States)

    Boothroyd, Lynda G.; McLaughlin, Edward

    2011-01-01

    The primary theoretical framework for the study of human physical attraction is currently Darwinian sexual selection. Not only has this perspective enabled the discovery of what appear to be strong universals in human mate choice but it has also facilitated our understanding of systematic variation in preferences both between and within…

  12. Cellular automata-based artificial life system of horizontal gene transfer

    Directory of Open Access Journals (Sweden)

    Ji-xin Liu

    2016-02-01

    Full Text Available Mutation and natural selection is the core of Darwin's idea about evolution. Many algorithms and models are based on this idea. However, in the evolution of prokaryotes, more and more researches have indicated that horizontal gene transfer (HGT would be much more important and universal than the authors had imagined. Owing to this mechanism, the prokaryotes not only become adaptable in nearly any environment on Earth, but also form a global genetic bank and a super communication network with all the genes of the prokaryotic world. Under this background, they present a novel cellular automata model general gene transfer to simulate and study the vertical gene transfer and HGT in the prokaryotes. At the same time, they use Schrodinger's life theory to formulate some evaluation indices and to discuss the intelligence and cognition of prokaryotes which is derived from HGT.

  13. Numerical Analysis of Characteristics of Cellular Counterflow Diffusion Flames near Radiative Extinction Limit

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Su Ryong [Seoul National University of Technology, Seoul (Korea, Republic of)

    2014-06-15

    Nonlinear characteristics of cellular counterflow diffusion flame near the radiative extinction limit at large Damköhler number are numerically investigated. Lewis number is assumed to be 0.5 and flame evolution is calculated by imposing an infinitesimal disturbance to a one-dimensional(1-D) steady state flame. The early stage of nonlinear development is very similar to that predicted in a linear stability analysis. The disturbance with the wavenumber of the fastest growing mode emerges and grows gradually. Eventual, an alternating pattern of reacting and quenching stripes is developed. The cellular flame temperature is higher than that of 1-D flame because of the gain of the total enthalpy. As the Damköhler number is further increased, the shape of the cell becomes circular to increase the surface area per unit reacting volume. The cellular flames do not extinguish but survive even above the 1-D steady state extinction condition.

  14. a Predator-Prey Model Based on the Fully Parallel Cellular Automata

    Science.gov (United States)

    He, Mingfeng; Ruan, Hongbo; Yu, Changliang

    We presented a predator-prey lattice model containing moveable wolves and sheep, which are characterized by Penna double bit strings. Sexual reproduction and child-care strategies are considered. To implement this model in an efficient way, we build a fully parallel Cellular Automata based on a new definition of the neighborhood. We show the roles played by the initial densities of the populations, the mutation rate and the linear size of the lattice in the evolution of this model.

  15. Study on Parameter Optimization Design of Drum Brake Based on Hybrid Cellular Multiobjective Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2012-01-01

    Full Text Available In consideration of the significant role the brake plays in ensuring the fast and safe running of vehicles, and since the present parameter optimization design models of brake are far from the practical application, this paper proposes a multiobjective optimization model of drum brake, aiming at maximizing the braking efficiency and minimizing the volume and temperature rise of drum brake. As the commonly used optimization algorithms are of some deficiency, we present a differential evolution cellular multiobjective genetic algorithm (DECell by introducing differential evolution strategy into the canonical cellular genetic algorithm for tackling this problem. For DECell, the gained Pareto front could be as close as possible to the exact Pareto front, and also the diversity of nondominated individuals could be better maintained. The experiments on the test functions reveal that DECell is of good performance in solving high-dimension nonlinear multiobjective problems. And the results of optimizing the new brake model indicate that DECell obviously outperforms the compared popular algorithm NSGA-II concerning the number of obtained brake design parameter sets, the speed, and stability for finding them.

  16. Evolution of senescence in nature: physiological evolution in populations of garter snake with divergent life histories.

    Science.gov (United States)

    Robert, Kylie A; Bronikowski, Anne M

    2010-02-01

    Evolutionary theories of aging are linked to life-history theory in that age-specific schedules of reproduction and survival determine the trajectory of age-specific mutation/selection balances across the life span and thus the rate of senescence. This is predicted to manifest at the organismal level in the evolution of energy allocation strategies of investing in somatic maintenance and robust stress responses in less hazardous environments in exchange for energy spent on growth and reproduction. Here we report experiments from long-studied populations of western terrestrial garter snakes (Thamnophis elegans) that reside in low and high extrinsic mortality environments, with evolved long and short life spans, respectively. Laboratory common-environment colonies of these two ecotypes were tested for a suite of physiological traits after control and stressed gestations. In offspring derived from control and corticosterone-treated dams, we measured resting metabolism; mitochondrial oxygen consumption, ATP and free radical production rates; and erythrocyte DNA damage and repair ability. We evaluated whether these aging biomarkers mirrored the evolution of life span and whether they were sensitive to stress. Neonates from the long-lived ecotype (1) were smaller, (2) consumed equal amounts of oxygen when corrected for body mass, (3) had DNA that damaged more readily but repaired more efficiently, and (4) had more efficient mitochondria and more efficient cellular antioxidant defenses than short-lived snakes. Many ecotype differences were enhanced in offspring derived from stress-treated dams, which supports the conclusion that nongenetic maternal effects may further impact the cellular stress defenses of offspring. Our findings reveal that physiological evolution underpins reptilian life histories and sheds light on the connectedness between stress response and aging pathways in wild-dwelling organisms.

  17. A cellular automata model of traffic flow with variable probability of randomization

    International Nuclear Information System (INIS)

    Zheng Wei-Fan; Zhang Ji-Ye

    2015-01-01

    Research on the stochastic behavior of traffic flow is important to understand the intrinsic evolution rules of a traffic system. By introducing an interactional potential of vehicles into the randomization step, an improved cellular automata traffic flow model with variable probability of randomization is proposed in this paper. In the proposed model, the driver is affected by the interactional potential of vehicles before him, and his decision-making process is related to the interactional potential. Compared with the traditional cellular automata model, the modeling is more suitable for the driver’s random decision-making process based on the vehicle and traffic situations in front of him in actual traffic. From the improved model, the fundamental diagram (flow–density relationship) is obtained, and the detailed high-density traffic phenomenon is reproduced through numerical simulation. (paper)

  18. Simulation of earthquakes with cellular automata

    Directory of Open Access Journals (Sweden)

    P. G. Akishin

    1998-01-01

    Full Text Available The relation between cellular automata (CA models of earthquakes and the Burridge–Knopoff (BK model is studied. It is shown that the CA proposed by P. Bak and C. Tang,although they have rather realistic power spectra, do not correspond to the BK model. We present a modification of the CA which establishes the correspondence with the BK model.An analytical method of studying the evolution of the BK-like CA is proposed. By this method a functional quadratic in stress release, which can be regarded as an analog of the event energy, is constructed. The distribution of seismic events with respect to this “energy” shows rather realistic behavior, even in two dimensions. Special attention is paid to two-dimensional automata; the physical restrictions on compression and shear stiffnesses are imposed.

  19. The essence of life.

    Science.gov (United States)

    Ma, Wentao

    2016-09-26

    Although biology has achieved great successes in recent years, we have not got a clear idea on "what is life?" Actually, as explained here, the main reason for this situation is that there are two completely distinct aspects for "life", which are usually talked about together. Indeed, in respect to these two aspects: Darwinian evolution and self-sustaining, we must split the concept of life correspondingly, for example, by defining "life form" and "living entity", separately. For life's implementation (related to the two aspects) in nature, three mechanisms are crucial: the replication of DNA/RNA-like polymers by residue-pairing, the sequence-dependent folding of RNA/protein-like polymers engendering special functions, and the assembly of phospholipid-like amphiphiles forming vesicles. The notion "information" is significant for us to comprehend life phenomenon: the life form of a living entity can just be defined by its genetic information; Darwinian evolution is essentially an evolution of such information, transferred across generations. The in-depth analysis concerning the essence of life would improve our cognition in the whole field of biology, and may have a direct influence on its subfields like the origin of life, artificial life and astrobiology. This article was reviewed by Anthony Poole and Thomas Dandekar.

  20. What makes biology unique?: considerations on the autonomy of a scientific discipline

    National Research Council Canada - National Science Library

    Mayr, Ernst

    2004-01-01

    ... of evolution is actually five separate theories, each with its own history, trajectory, and impact. Natural selection is a separate idea from common descent, and from geographic speciation, and so on. A number of the perennial Darwinian controversies may well have been caused by the confounding of the five separate theories into a single composite. Tho...

  1. Gehlen, Darwin e la salamandra

    Directory of Open Access Journals (Sweden)

    RASINI, VALLORI

    2016-12-01

    Full Text Available Gehlen, Darwin and the Salamander Arnold Gehlen creates a theory of man as “lacking being” that leads to a theory of a “superior being”. Man is radically different from animal, and Gehlen uses the biological idea of human neoteny to refuse the Darwinian theory of human evolution. However his arguments are preconceived and ineffectual.

  2. From forest and agro-ecosystems to the microecosystems of the human body: what can landscape ecology tell us about tumor growth, metastasis, and treatment options?

    Science.gov (United States)

    Daoust, Simon P; Fahrig, Lenore; Martin, Amanda E; Thomas, Frédéric

    2013-01-01

    Cancer is now understood to be a process that follows Darwinian evolution. Heterogeneous populations of cancerous cells that make up the tumor inhabit the tissue 'microenvironment', where ecological interactions analogous to predation and competition for resources drive the somatic evolution of cancer. The tumor microenvironment plays a crucial role in the tumor genesis, development, and metastasis processes, as it creates the microenvironmental selection forces that ultimately determine the cellular characteristics that result in the greatest fitness. Here, we explore and offer new insights into the spatial aspects of tumor-microenvironment interactions through the application of landscape ecology theory to tumor growth and metastasis within the tissue microhabitat. We argue that small tissue microhabitats in combination with the spatial distribution of resources within these habitats could be important selective forces driving tumor invasiveness. We also contend that the compositional and configurational heterogeneity of components in the tissue microhabitat do not only influence resource availability and functional connectivity but also play a crucial role in facilitating metastasis and may serve to explain, at least in part, tissue tropism in certain cancers. This novel work provides a compelling argument for the necessity of taking into account the structure of the tissue microhabitat when investigating tumor progression.

  3. Darwin-Wallace Demons: survival of the fastest in populations of duckweeds and the evolutionary history of an enigmatic group of angiosperms.

    Science.gov (United States)

    Kutschera, U; Niklas, K J

    2015-01-01

    In evolutionary biology, the term 'Darwinian fitness' refers to the lifetime reproductive success of an individual within a population of conspecifics. The idea of a 'Darwinian Demon' emerged from this concept and is defined here as an organism that commences reproduction almost immediately after birth, has a maximum fitness, and lives forever. It has been argued that duckweeds (sub-family Lemnoideae, order Alismatales), a group containing five genera and 34 species of small aquatic monocotyledonous plants with a reduced body plan, can be interpreted as examples of 'Darwinian Demons'. Here we focus on the species Spirodela polyrhiza (Great duckweed) and show that these miniaturised aquatic angiosperms display features that fit the definition of the hypothetical organism that we will call a 'Darwin-Wallace Demon' in recognition of the duel proponents of evolution by natural selection. A quantitative analysis (log-log bivariate plot of annual growth in dry biomass versus standing dry body mass of various green algae and land plants) revealed that duckweeds are thus far the most rapidly growing angiosperms in proportion to their body mass. In light of this finding, we discuss the disposable soma and metabolic optimising theories, summarise evidence for and against the proposition that the Lemnoideae (family Araceae) reflect an example of reductive evolution, and argue that, under real-world conditions (environmental constraints and other limitations), 'Darwin-Wallace Demons' cannot exist, although the concept remains useful in much the same way that the Hardy-Weinberg law does. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

  4. Some issues concerning applications of naturalistic paradigm to the study of religion

    Directory of Open Access Journals (Sweden)

    Kinga Kowalczyk-Purol

    2014-01-01

    Full Text Available Viewing religion as a product of evolution already has yielded a new and interesting hypotheses, which could help to integrate entire heritage of scientific study of religion. Nonetheless, there are some objections toward this program. First, despite the fact that evolutionary theories of religion are inherently interdisciplinary, its integration with sociological, anthropological and historical studies should be improve in the future. Second, phenomenological descriptions (that is individual religious experiences are neglected by Darwinians. This fact could negatively affects explanatory potential of this approach. Finally, opponents of analyzed paradigm state that evolutionary hypotheses have still low level of confirmation. It stems from a small number of conducted empirical investigations on evolutionary roots of religion. Nevertheless, application of Darwinian tools to the study of religion remains a very promising scientific venture.

  5. PV-Powered CoMP-Based Green Cellular Networks with a Standby Grid Supply

    Directory of Open Access Journals (Sweden)

    Abu Jahid

    2017-01-01

    Full Text Available This paper proposes a novel framework for PV-powered cellular networks with a standby grid supply and an essential energy management technique for achieving envisaged green networks. The proposal considers an emerging cellular network architecture employing two types of coordinated multipoint (CoMP transmission techniques for serving the subscribers. Under the proposed framework, each base station (BS is powered by an individual PV solar energy module having an independent storage device. BSs are also connected to the conventional grid supply for meeting additional energy demand. We also propose a dynamic inter-BS solar energy sharing policy through a transmission line for further greening the proposed network by minimizing the consumption from the grid supply. An extensive simulation-based study in the downlink of a Long-Term Evolution (LTE cellular system is carried out for evaluating the energy efficiency performance of the proposed framework. System performance is also investigated for identifying the impact of various system parameters including storage factor, storage capacity, solar generation capacity, transmission line loss, and different CoMP techniques.

  6. Evolution of trappin genes in mammals

    Directory of Open Access Journals (Sweden)

    Furutani Yutaka

    2010-01-01

    Full Text Available Abstract Background Trappin is a multifunctional host-defense peptide that has antiproteolytic, antiinflammatory, and antimicrobial activities. The numbers and compositions of trappin paralogs vary among mammalian species: human and sheep have a single trappin-2 gene; mouse and rat have no trappin gene; pig and cow have multiple trappin genes; and guinea pig has a trappin gene and two other derivativegenes. Independent duplications of trappin genes in pig and cow were observed recently after the species were separated. To determine whether these trappin gene duplications are restricted only to certain mammalian lineages, we analyzed recently-developed genome databases for the presence of duplicate trappin genes. Results The database analyses revealed that: 1 duplicated trappin multigenes were found recently in the nine-banded armadillo; 2 duplicated two trappin genes had been found in the Afrotherian species (elephant, tenrec, and hyrax since ancient days; 3 a single trappin-2 gene was found in various eutherians species; and 4 no typical trappin gene has been found in chicken, zebra finch, and opossum. Bayesian analysis estimated the date of the duplication of trappin genes in the Afrotheria, guinea pig, armadillo, cow, and pig to be 244, 35, 11, 13, and 3 million-years ago, respectively. The coding regions of trappin multigenes of almadillo, bovine, and pig evolved much faster than the noncoding exons, introns, and the flanking regions, showing that these genes have undergone accelerated evolution, and positive Darwinian selection was observed in pig-specific trappin paralogs. Conclusion These results suggest that trappin is an eutherian-specific molecule and eutherian genomes have the potential to form trappin multigenes.

  7. Max–min-plus expressions for one-dimensional particle cellular automata obtained from a fundamental diagram

    International Nuclear Information System (INIS)

    Okumura, Takazumi; Matsukidaira, Junta; Takahashi, Daisuke

    2013-01-01

    We study one-dimensional neighborhood-five conservative cellular automata (CA), referred to as particle cellular automata five (particle CA5). We show that evolution equations for particle CA5s that belong to certain types can be obtained in the form of max–min-plus expressions from a fundamental diagram. The obtained equations are transformed into other max–min-plus expressions by ultradiscrete Cole–Hopf transformations, which enable us to analyze the asymptotic behaviors of general solutions. The equations in the Lagrange representation, which describe particle motion, are also presented, which can also be obtained from a fundamental diagram. Finally, we discuss the generalization to a one-dimensional conservative neighborhood-n CA, i.e., particle CAn. (paper)

  8. Adaptive evolution of cytochrome c oxidase: Infrastructure for a carnivorous plant radiation

    OpenAIRE

    Jobson, Richard W.; Nielsen, Rasmus; Laakkonen, Liisa; Wikström, Mårten; Albert, Victor A.

    2004-01-01

    Much recent attention in the study of adaptation of organismal form has centered on developmental regulation. As such, the highly conserved respiratory machinery of eukaryotic cells might seem an unlikely target for selection supporting novel morphologies. We demonstrate that a dramatic molecular evolutionary rate increase in subunit I of cytochrome c oxidase (COX) from an active-trapping lineage of carnivorous plants is caused by positive Darwinian selection. Bladderworts (Utricularia) trap ...

  9. Cellular gravity

    NARCIS (Netherlands)

    F.C. Gruau; J.T. Tromp (John)

    1999-01-01

    textabstractWe consider the problem of establishing gravity in cellular automata. In particular, when cellular automata states can be partitioned into empty, particle, and wall types, with the latter enclosing rectangular areas, we desire rules that will make the particles fall down and pile up on

  10. A los 150 años desde "El origen de las especies": ¿es darwinista la biología contemporánea? At 150 years since "The origin of species": Is contemporary biology Darwinian?

    Directory of Open Access Journals (Sweden)

    GUILLERMO FOLGUERA

    2009-12-01

    Full Text Available A los 150 años de la publicación de "El origen de las especies" de Charles Darwin, numerosos homenajes se han realizado en diferentes ciudades del mundo. Sin embargo, es importante preguntarse hacia el seno de la comunidad científica acerca del alcance efectivo del darwinisimo dentro de la biología. En este trabajo analizamos este supuesto intentando responder, al menos de una manera aproximativa, la pregunta: ¿es darwinista la biología en la actualidad? A estos fines, consideramos algunos de los principales aportes que suelen asignarse al darwinismo en las ciencias de los sistemas vivos: el análisis y centro en la diversidad, un origen único de los sistemas vivos, la incorporación del azar y el reconocimiento de las causas proximales. En términos generales detectamos importantes líneas de continuidad entre el darwinismo y las diferentes disciplinas que componen a la biología contemporánea. Sin embargo, esta situación dista de ser general y no ocurre para todas las ideas analizadas. En este sentido, en algunas áreas del conocimiento el darwinismo solo se ha filtrado mediante la implementación de recortes significativos (tal como el caso de la reducción de los procesos evolutivos a la selección natural, o bien a través de aspectos que aún no son debidamente incorporados en la investigación científica (tal como en el caso del estudio de la variabilidad. Por lo tanto, la futura incorporación de estos elementos se presenta como un desafío importante para lograr una biología integradora.After 150 years of the publication of the Origin of Species by Charles Darwin, a number of tributes had honored him worldwide. However, it seems important to ask about the effective application of Darwin's ideas within the biological disciplines. Herein we analyze this problem trying to answer the question: is contemporary biology Darwinian? To this end, we consider some of the main assumed contributions of Darwinism to the sciences of living

  11. Multiuser Scheduling on the Downlink of an LTE Cellular System

    Directory of Open Access Journals (Sweden)

    Raymond Kwan

    2008-01-01

    Full Text Available The challenge of scheduling user transmissions on the downlink of a long-term evolution (LTE cellular communication system is addressed. In particular, a novel optimalmultiuser scheduler is proposed. Numerical results show that the system performance improves with increasing correlation among OFDMA subcarriers. It is found that only a limited amount of feedback information is needed to achieve relatively good performance. A suboptimal reduced-complexity scheduler is also proposed and shown to provide good performance. The suboptimal scheme is especially attractive when the number of users is large, in which case the complexity of the optimal scheme is high.

  12. Uniform and localized corrosion modelling by means of probabilistic cellular automata

    International Nuclear Information System (INIS)

    Perez-Brokate, Cristian

    2016-01-01

    Numerical modelling is complementary tool for corrosion prediction. The objective of this work is to develop a corrosion model by means of a probabilistic cellular automata approach at a mesoscopic scale. In this work, we study the morphological evolution and kinetics of corrosion. This model couples electrochemical oxidation and reduction reactions. Regarding kinetics, cellular automata models are able to describe current as a function of the applied potential for a redox reaction on an inert electrode. The inclusion of probabilities allows the description of the stochastic nature of anodic and cathodic reactions. Corrosion morphology has been studied in different context: generalised corrosion, pitting corrosion and corrosion in an occluded environment. a general tendency of two regimes is found. a first regime of uniform corrosion where the anodic and cathodic reactions occur homogeneously over the surface. a second regime of localized corrosion when there is a spatial separation of anodic and cathodic zones, with an increase of anodic reaction rate. (author) [fr

  13. Increase in Complexity and Information through Molecular Evolution

    Directory of Open Access Journals (Sweden)

    Peter Schuster

    2016-11-01

    Full Text Available Biological evolution progresses by essentially three different mechanisms: (I optimization of properties through natural selection in a population of competitors; (II development of new capabilities through cooperation of competitors caused by catalyzed reproduction; and (III variation of genetic information through mutation or recombination. Simplified evolutionary processes combine two out of the three mechanisms: Darwinian evolution combines competition (I and variation (III and is represented by the quasispecies model, major transitions involve cooperation (II of competitors (I, and the third combination, cooperation (II and variation (III provides new insights in the role of mutations in evolution. A minimal kinetic model based on simple molecular mechanisms for reproduction, catalyzed reproduction and mutation is introduced, cast into ordinary differential equations (ODEs, and analyzed mathematically in form of its implementation in a flow reactor. Stochastic aspects are investigated through computer simulation of trajectories of the corresponding chemical master equations. The competition-cooperation model, mechanisms (I and (II, gives rise to selection at low levels of resources and leads to symbiontic cooperation in case the material required is abundant. Accordingly, it provides a kind of minimal system that can undergo a (major transition. Stochastic effects leading to extinction of the population through self-enhancing oscillations destabilize symbioses of four or more partners. Mutations (III are not only the basis of change in phenotypic properties but can also prevent extinction provided the mutation rates are sufficiently large. Threshold phenomena are observed for all three combinations: The quasispecies model leads to an error threshold, the competition-cooperation model allows for an identification of a resource-triggered bifurcation with the transition, and for the cooperation-mutation model a kind of stochastic threshold for

  14. Physical-layer Network Coding in Two-Way Heterogeneous Cellular Networks with Power Imbalance

    OpenAIRE

    Thampi, Ajay K; Liew, Soung Chang; Armour, Simon M D; Fan, Zhong; You, Lizhao; Kaleshi, Dritan

    2016-01-01

    The growing demand for high-speed data, quality of service (QoS) assurance and energy efficiency has triggered the evolution of 4G LTE-A networks to 5G and beyond. Interference is still a major performance bottleneck. This paper studies the application of physical-layer network coding (PNC), a technique that exploits interference, in heterogeneous cellular networks. In particular, we propose a rate-maximising relay selection algorithm for a single cell with multiple relays assuming the decode...

  15. Linear reversible second-order cellular automata and their first-order matrix equivalents

    Science.gov (United States)

    Macfarlane, A. J.

    2004-11-01

    Linear or one-dimensional reversible second-order cellular automata, exemplified by three cases named as RCA1-3, are introduced. Displays of their evolution in discrete time steps, &{\\in}Z_2;) as for RCA1-3. MCA1-3 are tractable because it has been possible to generalize to them the heavy duty methods already well-developed for ordinary first-order cellular automata like those of Wolfram's Rules 90 and 150. While the automata MCA1-3 are thought to be of genuine interest in their own right, with untapped further mathematical potential, their treatment has been applied here to expediting derivation of a large body of general and explicit results for N(t) for RCA1-3. Amongst explicit results obtained are formulas also for each of RCA1-3 for the total weight of the configurations of the first &2^M; times, M =0, 1, 2,\\ldots.

  16. Cellular MR Imaging

    Directory of Open Access Journals (Sweden)

    Michel Modo

    2005-07-01

    Full Text Available Cellular MR imaging is a young field that aims to visualize targeted cells in living organisms. In order to provide a different signal intensity of the targeted cell, they are either labeled with MR contrast agents in vivo or prelabeled in vitro. Either (ultrasmall superparamagnetic iron oxide [(USPIO] particles or (polymeric paramagnetic chelates can be used for this purpose. For in vivo cellular labeling, Gd3+- and Mn2+- chelates have mainly been used for targeted hepatobiliary imaging, and (USPIO-based cellular imaging has been focused on imaging of macrophage activity. Several of these magneto-pharmaceuticals have been FDA-approved or are in late-phase clinical trials. As for prelabeling of cells in vitro, a challenge has been to induce a sufficient uptake of contrast agents into nonphagocytic cells, without affecting normal cellular function. It appears that this issue has now largely been resolved, leading to an active research on monitoring the cellular biodistribution in vivo following transplantation or transfusion of these cells, including cell migration and trafficking. New applications of cellular MR imaging will be directed, for instance, towards our understanding of hematopoietic (immune cell trafficking and of novel guided (stem cell-based therapies aimed to be translated to the clinic in the future.

  17. Reconstruction of DNA sequences using genetic algorithms and cellular automata: towards mutation prediction?

    Science.gov (United States)

    Mizas, Ch; Sirakoulis, G Ch; Mardiris, V; Karafyllidis, I; Glykos, N; Sandaltzopoulos, R

    2008-04-01

    Change of DNA sequence that fuels evolution is, to a certain extent, a deterministic process because mutagenesis does not occur in an absolutely random manner. So far, it has not been possible to decipher the rules that govern DNA sequence evolution due to the extreme complexity of the entire process. In our attempt to approach this issue we focus solely on the mechanisms of mutagenesis and deliberately disregard the role of natural selection. Hence, in this analysis, evolution refers to the accumulation of genetic alterations that originate from mutations and are transmitted through generations without being subjected to natural selection. We have developed a software tool that allows modelling of a DNA sequence as a one-dimensional cellular automaton (CA) with four states per cell which correspond to the four DNA bases, i.e. A, C, T and G. The four states are represented by numbers of the quaternary number system. Moreover, we have developed genetic algorithms (GAs) in order to determine the rules of CA evolution that simulate the DNA evolution process. Linear evolution rules were considered and square matrices were used to represent them. If DNA sequences of different evolution steps are available, our approach allows the determination of the underlying evolution rule(s). Conversely, once the evolution rules are deciphered, our tool may reconstruct the DNA sequence in any previous evolution step for which the exact sequence information was unknown. The developed tool may be used to test various parameters that could influence evolution. We describe a paradigm relying on the assumption that mutagenesis is governed by a near-neighbour-dependent mechanism. Based on the satisfactory performance of our system in the deliberately simplified example, we propose that our approach could offer a starting point for future attempts to understand the mechanisms that govern evolution. The developed software is open-source and has a user-friendly graphical input interface.

  18. Simulations of living cell origins using a cellular automata model.

    Science.gov (United States)

    Ishida, Takeshi

    2014-04-01

    Understanding the generalized mechanisms of cell self-assembly is fundamental for applications in various fields, such as mass producing molecular machines in nanotechnology. Thus, the details of real cellular reaction networks and the necessary conditions for self-organized cells must be elucidated. We constructed a 2-dimensional cellular automata model to investigate the emergence of biological cell formation, which incorporated a looped membrane and a membrane-bound information system (akin to a genetic code and gene expression system). In particular, with an artificial reaction system coupled with a thermal system, the simultaneous formation of a looped membrane and an inner reaction process resulted in a more stable structure. These double structures inspired the primitive biological cell formation process from chemical evolution stage. With a model to simulate cellular self-organization in a 2-dimensional cellular automata model, 3 phenomena could be realized: (1) an inner reaction system developed as an information carrier precursor (akin to DNA); (2) a cell border emerged (akin to a cell membrane); and (3) these cell structures could divide into 2. This double-structured cell was considered to be a primary biological cell. The outer loop evolved toward a lipid bilayer membrane, and inner polymeric particles evolved toward precursor information carriers (evolved toward DNA). This model did not completely clarify all the necessary and sufficient conditions for biological cell self-organization. Further, our virtual cells remained unstable and fragile. However, the "garbage bag model" of Dyson proposed that the first living cells were deficient; thus, it would be reasonable that the earliest cells were more unstable and fragile than the simplest current unicellular organisms.

  19. Programmable cellular arrays. Faults testing and correcting in cellular arrays

    International Nuclear Information System (INIS)

    Cercel, L.

    1978-03-01

    A review of some recent researches about programmable cellular arrays in computing and digital processing of information systems is presented, and includes both combinational and sequential arrays, with full arbitrary behaviour, or which can realize better implementations of specialized blocks as: arithmetic units, counters, comparators, control systems, memory blocks, etc. Also, the paper presents applications of cellular arrays in microprogramming, in implementing of a specialized computer for matrix operations, in modeling of universal computing systems. The last section deals with problems of fault testing and correcting in cellular arrays. (author)

  20. Addressing population heterogeneity and distribution in epidemics models using a cellular automata approach.

    Science.gov (United States)

    López, Leonardo; Burguerner, Germán; Giovanini, Leonardo

    2014-04-12

    The spread of an infectious disease is determined by biological and social factors. Models based on cellular automata are adequate to describe such natural systems consisting of a massive collection of simple interacting objects. They characterize the time evolution of the global system as the emergent behaviour resulting from the interaction of the objects, whose behaviour is defined through a set of simple rules that encode the individual behaviour and the transmission dynamic. An epidemic is characterized trough an individual-based-model built upon cellular automata. In the proposed model, each individual of the population is represented by a cell of the automata. This way of modeling an epidemic situation allows to individually define the characteristic of each individual, establish different scenarios and implement control strategies. A cellular automata model to study the time evolution of a heterogeneous populations through the various stages of disease was proposed, allowing the inclusion of individual heterogeneity, geographical characteristics and social factors that determine the dynamic of the desease. Different assumptions made to built the classical model were evaluated, leading to following results: i) for low contact rate (like in quarantine process or low density population areas) the number of infective individuals is lower than other areas where the contact rate is higher, and ii) for different initial spacial distributions of infected individuals different epidemic dynamics are obtained due to its influence on the transition rate and the reproductive ratio of disease. The contact rate and spatial distributions have a central role in the spread of a disease. For low density populations the spread is very low and the number of infected individuals is lower than in highly populated areas. The spacial distribution of the population and the disease focus as well as the geographical characteristic of the area play a central role in the dynamics of the

  1. Ultrastructure, macromolecules, and evolution

    CERN Document Server

    Dillon, Lawrence S

    1981-01-01

    Thus far in the history of biology, two, and only two, fundamental principles have come to light that pervade and unify the entire science-the cell theory and the concept of evolution. While it is true that recently opened fields of inves­ tigation have given rise to several generalizations of wide impact, such as the universality of DNA and the energetic dynamics of ecology, closer inspection reveals them to be part and parcel of either of the first two mentioned. Because in the final analysis energy can act upon an organism solely at the cellular level, its effects may be perceived basically to represent one facet of cell me­ tabolism. Similarly, because the DNA theory centers upon the means by which cells build proteins and reproduce themselves, it too proves to be only one more, even though an exciting, aspect of the cell theory. In fact, if the matter is given closer scrutiny, evolution itself can be viewed as being a fundamental portion of the cell concept, for its effects arise only as a consequence ...

  2. 47 CFR 22.970 - Unacceptable interference to part 90 non-cellular 800 MHz licensees from cellular radiotelephone...

    Science.gov (United States)

    2010-10-01

    ...-cellular 800 MHz licensees from cellular radiotelephone or part 90-800 MHz cellular systems. 22.970 Section... MOBILE SERVICES Cellular Radiotelephone Service § 22.970 Unacceptable interference to part 90 non-cellular 800 MHz licensees from cellular radiotelephone or part 90-800 MHz cellular systems. (a) Definition...

  3. Monte Carlo molecular simulations: improving the statistical efficiency of samples with the help of artificial evolution algorithms; Simulations moleculaires de Monte Carlo: amelioration de l'efficacite statistique de l'echantillonnage grace aux algorithmes d'evolution artificielle

    Energy Technology Data Exchange (ETDEWEB)

    Leblanc, B.

    2002-03-01

    Molecular simulation aims at simulating particles in interaction, describing a physico-chemical system. When considering Markov Chain Monte Carlo sampling in this context, we often meet the same problem of statistical efficiency as with Molecular Dynamics for the simulation of complex molecules (polymers for example). The search for a correct sampling of the space of possible configurations with respect to the Boltzmann-Gibbs distribution is directly related to the statistical efficiency of such algorithms (i.e. the ability of rapidly providing uncorrelated states covering all the configuration space). We investigated how to improve this efficiency with the help of Artificial Evolution (AE). AE algorithms form a class of stochastic optimization algorithms inspired by Darwinian evolution. Efficiency measures that can be turned into efficiency criteria have been first searched before identifying parameters that could be optimized. Relative frequencies for each type of Monte Carlo moves, usually empirically chosen in reasonable ranges, were first considered. We combined parallel simulations with a 'genetic server' in order to dynamically improve the quality of the sampling during the simulations progress. Our results shows that in comparison with some reference settings, it is possible to improve the quality of samples with respect to the chosen criterion. The same algorithm has been applied to improve the Parallel Tempering technique, in order to optimize in the same time the relative frequencies of Monte Carlo moves and the relative frequencies of swapping between sub-systems simulated at different temperatures. Finally, hints for further research in order to optimize the choice of additional temperatures are given. (author)

  4. Evolution of cooperation: combining kin selection and reciprocal altruism into matrix games with social dilemmas.

    Directory of Open Access Journals (Sweden)

    Som B Ale

    Full Text Available Darwinian selection should preclude cooperation from evolving; yet cooperation is widespread among organisms. We show how kin selection and reciprocal altruism can promote cooperation in diverse 2×2 matrix games (prisoner's dilemma, snowdrift, and hawk-dove. We visualize kin selection as non-random interactions with like-strategies interacting more than by chance. Reciprocal altruism emerges from iterated games where players have some likelihood of knowing the identity of other players. This perspective allows us to combine kin selection and reciprocal altruism into a general matrix game model. Both mechanisms operating together should influence the evolution of cooperation. In the absence of kin selection, reciprocal altruism may be an evolutionarily stable strategy but is unable to invade a population of non-co-operators. Similarly, it may take a high degree of relatedness to permit cooperation to supplant non-cooperation. Together, a little bit of reciprocal altruism can, however, greatly reduce the threshold at which kin selection promotes cooperation, and vice-versa. To properly frame applications and tests of cooperation, empiricists should consider kin selection and reciprocal altruism together rather than as alternatives, and they should be applied to a broader class of social dilemmas than just the prisoner's dilemma.

  5. Heterogeneous cellular networks

    CERN Document Server

    Hu, Rose Qingyang

    2013-01-01

    A timely publication providing coverage of radio resource management, mobility management and standardization in heterogeneous cellular networks The topic of heterogeneous cellular networks has gained momentum in industry and the research community, attracting the attention of standardization bodies such as 3GPP LTE and IEEE 802.16j, whose objectives are looking into increasing the capacity and coverage of the cellular networks. This book focuses on recent progresses,  covering the related topics including scenarios of heterogeneous network deployment, interference management i

  6. 47 CFR 22.909 - Cellular markets.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Cellular markets. 22.909 Section 22.909... Cellular Radiotelephone Service § 22.909 Cellular markets. Cellular markets are standard geographic areas used by the FCC for administrative convenience in the licensing of cellular systems. Cellular markets...

  7. Early 20th-century research at the interfaces of genetics, development, and evolution: reflections on progress and dead ends.

    Science.gov (United States)

    Deichmann, Ute

    2011-09-01

    Three early 20th-century attempts at unifying separate areas of biology, in particular development, genetics, physiology, and evolution, are compared in regard to their success and fruitfulness for further research: Jacques Loeb's reductionist project of unifying approaches by physico-chemical explanations; Richard Goldschmidt's anti-reductionist attempts to unify by integration; and Sewall Wright's combination of reductionist research and vision of hierarchical genetic systems. Loeb's program, demanding that all aspects of biology, including evolution, be studied by the methods of the experimental sciences, proved highly successful and indispensible for higher level investigations, even though evolutionary change and properties of biological systems up to now cannot be fully explained on the molecular level alone. Goldschmidt has been appraised as pioneer of physiological and developmental genetics and of a new evolutionary synthesis which transcended neo-Darwinism. However, this study concludes that his anti-reductionist attempts to integrate genetics, development and evolution have to be regarded as failures or dead ends. His grand speculations were based on the one hand on concepts and experimental systems that were too vague in order to stimulate further research, and on the other on experiments which in their core parts turned out not to be reproducible. In contrast, Sewall Wright, apart from being one of the architects of the neo-Darwinian synthesis of the 1930s, opened up new paths of testable quantitative developmental genetic investigations. He placed his research within a framework of logical reasoning, which resulted in the farsighted speculation that examinations of biological systems should be related to the regulation of hierarchical genetic subsystems, possibly providing a mechanism for development and evolution. I argue that his suggestion of basing the study of systems on clearly defined properties of the components has proved superior to

  8. Numerical simulations of cellular detonation diffraction in a stable gaseous mixture

    Directory of Open Access Journals (Sweden)

    Jian Li

    2016-09-01

    Full Text Available In this paper, the diffraction phenomenon of gaseous cellular detonations emerging from a confined tube into a sudden open space is simulated using the reactive Euler equations with a two-step Arrhenius chemistry model. Both two-dimensional and axisymmetric configurations are used for modeling cylindrical and spherical expansions, respectively. The chemical parameters are chosen for a stable gaseous explosive mixture in which the cellular detonation structure is highly regular. Adaptive mesh refinement (AMR is used to resolve the detonation wave structure and its evolution during the transmission. The numerical results show that the critical channel width and critical diameter over the detonation cell size are about 13±1 and 25±1, respectively. These numerical findings are comparable with the experimental observation and confirm again that the critical channel width and critical diameter differ essentially by a factor close to 2, equal to the geometrical scaling based on front curvature theory. Unlike unstable mixtures where instabilities manifested in the detonation front structure play a significant role during the transmission, the present numerical results and the observed geometrical scaling provide again evidence that the failure of detonation diffraction in stable mixtures with a regular detonation cellular pattern is dominantly caused by the global curvature due to the wave divergence resulting in the global decoupling of the reaction zone with the expanding shock front.

  9. Characterization of Morphological and Cellular Events Underlying Oral Regeneration in the Sea Anemone, Nematostella vectensis

    Directory of Open Access Journals (Sweden)

    Aldine R. Amiel

    2015-12-01

    Full Text Available Cnidarians, the extant sister group to bilateria, are well known for their impressive regenerative capacity. The sea anemone Nematostella vectensis is a well-established system for the study of development and evolution that is receiving increased attention for its regenerative capacity. Nematostella is able to regrow missing body parts within five to six days after its bisection, yet studies describing the morphological, cellular, and molecular events underlying this process are sparse and very heterogeneous in their experimental approaches. In this study, we lay down the basic framework to study oral regeneration in Nematostella vectensis. Using various imaging and staining techniques we characterize in detail the morphological, cellular, and global molecular events that define specific landmarks of this process. Furthermore, we describe in vivo assays to evaluate wound healing success and the initiation of pharynx reformation. Using our described landmarks for regeneration and in vivo assays, we analyze the effects of perturbing either transcription or cellular proliferation on the regenerative process. Interestingly, neither one of these experimental perturbations has major effects on wound closure, although they slightly delay or partially block it. We further show that while the inhibition of transcription blocks regeneration in a very early step, inhibiting cellular proliferation only affects later events such as pharynx reformation and tentacle elongation.

  10. The evolution of extreme altruism and inequality in insect societies.

    Science.gov (United States)

    Ratnieks, Francis L W; Helanterä, Heikki

    2009-11-12

    In eusocial organisms, some individuals specialize in reproduction and others in altruistic helping. The evolution of eusociality is, therefore, also the evolution of remarkable inequality. For example, a colony of honeybees (Apis mellifera) may contain 50 000 females all of whom can lay eggs. But 100 per cent of the females and 99.9 per cent of the males are offspring of the queen. How did such extremes evolve? Phylogenetic analyses show that high relatedness was almost certainly necessary for the origin of eusociality. However, even the highest family levels of kinship are insufficient to cause the extreme inequality seen in e.g. honeybees via 'voluntary altruism'. 'Enforced altruism' is needed, i.e. social pressures that deter individuals from attempting to reproduce. Coercion acts at two stages in an individual's life cycle. Queens are typically larger so larvae can be coerced into developing into workers by being given less food. Workers are coerced into working by 'policing', in which workers or the queen eat worker-laid eggs or aggress fertile workers. In some cases, individuals rebel, such as when stingless bee larvae develop into dwarf queens. The incentive to rebel is strong as an individual is the most closely related to its own offspring. However, because individuals gain inclusive fitness by rearing relatives, there is also a strong incentive to 'acquiesce' to social coercion. In a queenright honeybee colony, the policing of worker-laid eggs is very effective, which results in most workers working instead of attempting to reproduce. Thus, extreme altruism is due to both kinship and coercion. Altruism is frequently seen as a Darwinian puzzle but was not a puzzle that troubled Darwin. Darwin saw his difficulty in explaining how individuals that did not reproduce could evolve, given that natural selection was based on the accumulation of small heritable changes. The recognition that altruism is an evolutionary puzzle, and the solution was to wait another

  11. Biomechanics of cellular solids.

    Science.gov (United States)

    Gibson, Lorna J

    2005-03-01

    Materials with a cellular structure are widespread in nature and include wood, cork, plant parenchyma and trabecular bone. Natural cellular materials are often mechanically efficient: the honeycomb-like microstructure of wood, for instance, gives it an exceptionally high performance index for resisting bending and buckling. Here we review the mechanics of a wide range of natural cellular materials and examine their role in lightweight natural sandwich structures (e.g. iris leaves) and natural tubular structures (e.g. plant stems or animal quills). We also describe two examples of engineered biomaterials with a cellular structure, designed to replace or regenerate tissue in the body.

  12. Train flow chaos analysis based on an improved cellular automata model

    International Nuclear Information System (INIS)

    Meng, Xuelei; Xiang, Wanli; Jia, Limin; Xu, Jie

    2015-01-01

    To control the chaos in the railway traffic flow and offer valuable information for the dispatchers of the railway system, an improved cellular model is presented to detect and analyze the chaos in the traffic flow. We first introduce the working mechanism of moving block system, analyzing the train flow movement characteristics. Then we improve the cellular model on the evolution rules to adjust the train flow movement. We give the train operation steps from three cases: the trains running on a railway section, a train will arrive in a station and a train will departure from a station. We simulate 4 trains to run on a high speed section fixed with moving block system and record the distances between the neighbor trains and draw the Poincare section to analyze the chaos in the train operation. It is concluded that there is not only chaos but order in the train operation system with moving blocking system and they can interconvert to each other. The findings have the potential value in train dispatching system construction and offer supporting information for the daily dispatching work.

  13. Cellular Energy Absorbing TRIP-Steel/Mg-PSZ Composite: Honeycomb Structures Fabricated by a New Extrusion Powder Technology

    Directory of Open Access Journals (Sweden)

    Ulrich Martin

    2010-01-01

    Full Text Available Lightweight linear cellular composite materials on basis of austenite stainless TRIP- (TRansformation Induced Plasticity- steel as matrix with reinforcements of MgO partially stabilized zirconia (Mg-PSZ are described. Two-dimensional cellular materials for structural applications are conventionally produced by sheet expansion or corrugation processes. The presented composites are fabricated by a modified ceramic extrusion powder technology. Characterization of the microstructure in as-received and deformed conditions was carried out by optical and scanning electron microscopy. Magnetic balance measurements and electron backscatter diffraction (EBSD were used to identify the deformation-induced martensite evolution in the cell wall material. The honeycomb composite samples exhibit an increased strain hardening up to a certain engineering compressive strain and an extraordinary high specific energy absorption per unit mass and unit volume, respectively. Based on improved property-to-weight ratio such linear cellular structures will be of interest as crash absorbers or stiffened core materials for aerospace, railway, or automotive applications.

  14. Microstructural descriptors and cellular automata simulation of the effects of non-random nuclei location on recrystallization in two dimensions

    Directory of Open Access Journals (Sweden)

    Paulo Rangel Rios

    2006-06-01

    Full Text Available The effect of non-random nuclei location and the efficiency of microstructural descriptors in assessing such a situation are studied. Cellular automata simulation of recrystallization in two dimensions is carried out to simulate microstrutural evolution for nuclei distribution ranging from a periodic arrangement to clusters of nuclei. The simulation results are compared in detail with microstrutural descriptors normally used to follow transformation evolution. It is shown that the contiguity is particularly relevant to detect microstructural deviations from randomness. This work focuses on recrystallization but its results are applicable to any nucleation and growth transformation.

  15. Cellular Reflectarray Antenna

    Science.gov (United States)

    Romanofsky, Robert R.

    2010-01-01

    The cellular reflectarray antenna is intended to replace conventional parabolic reflectors that must be physically aligned with a particular satellite in geostationary orbit. These arrays are designed for specified geographical locations, defined by latitude and longitude, each called a "cell." A particular cell occupies nominally 1,500 square miles (3,885 sq. km), but this varies according to latitude and longitude. The cellular reflectarray antenna designed for a particular cell is simply positioned to align with magnetic North, and the antenna surface is level (parallel to the ground). A given cellular reflectarray antenna will not operate in any other cell.

  16. Cellular metabolic rate is influenced by life-history traits in tropical and temperate birds.

    Science.gov (United States)

    Jimenez, Ana Gabriela; Van Brocklyn, James; Wortman, Matthew; Williams, Joseph B

    2014-01-01

    In general, tropical birds have a "slow pace of life," lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR), proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR]), using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal's life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species.

  17. Cellular metabolic rate is influenced by life-history traits in tropical and temperate birds.

    Directory of Open Access Journals (Sweden)

    Ana Gabriela Jimenez

    Full Text Available In general, tropical birds have a "slow pace of life," lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR, proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR], using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal's life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species.

  18. Linearizable cellular automata

    International Nuclear Information System (INIS)

    Nobe, Atsushi; Yura, Fumitaka

    2007-01-01

    The initial value problem for a class of reversible elementary cellular automata with periodic boundaries is reduced to an initial-boundary value problem for a class of linear systems on a finite commutative ring Z 2 . Moreover, a family of such linearizable cellular automata is given

  19. Interpreting phenotypic antibiotic tolerance and persister cells as evolution via epigenetic inheritance.

    Science.gov (United States)

    Day, Troy

    2016-04-01

    Epigenetic inheritance is the transmission of nongenetic material such as gene expression levels, RNA and other biomolecules from parents to offspring. There is a growing realization that such forms of inheritance can play an important role in evolution. Bacteria represent a prime example of epigenetic inheritance because a large array of cellular components is transmitted to offspring, in addition to genetic material. Interestingly, there is an extensive and growing empirical literature showing that many bacteria can form 'persister' cells that are phenotypically resistant or tolerant to antibiotics, but most of these results are not interpreted within the context of epigenetic inheritance. Instead, persister cells are usually viewed as a genetically encoded bet-hedging strategy that has evolved in response to a fluctuating environment. Here I show, using a relatively simple model, that many of these empirical findings can be more simply understood as arising from a combination of epigenetic inheritance and cellular noise. I therefore suggest that phenotypic drug tolerance in bacteria might represent one of the best-studied examples of evolution under epigenetic inheritance. © 2016 John Wiley & Sons Ltd.

  20. Electromagnetic cellular interactions.

    Science.gov (United States)

    Cifra, Michal; Fields, Jeremy Z; Farhadi, Ashkan

    2011-05-01

    Chemical and electrical interaction within and between cells is well established. Just the opposite is true about cellular interactions via other physical fields. The most probable candidate for an other form of cellular interaction is the electromagnetic field. We review theories and experiments on how cells can generate and detect electromagnetic fields generally, and if the cell-generated electromagnetic field can mediate cellular interactions. We do not limit here ourselves to specialized electro-excitable cells. Rather we describe physical processes that are of a more general nature and probably present in almost every type of living cell. The spectral range included is broad; from kHz to the visible part of the electromagnetic spectrum. We show that there is a rather large number of theories on how cells can generate and detect electromagnetic fields and discuss experimental evidence on electromagnetic cellular interactions in the modern scientific literature. Although small, it is continuously accumulating. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Darwinian sex roles confirmed across the animal kingdom.

    Science.gov (United States)

    Janicke, Tim; Häderer, Ines K; Lajeunesse, Marc J; Anthes, Nils

    2016-02-01

    Since Darwin's conception of sexual selection theory, scientists have struggled to identify the evolutionary forces underlying the pervasive differences between male and female behavior, morphology, and physiology. The Darwin-Bateman paradigm predicts that anisogamy imposes stronger sexual selection on males, which, in turn, drives the evolution of conventional sex roles in terms of female-biased parental care and male-biased sexual dimorphism. Although this paradigm forms the cornerstone of modern sexual selection theory, it still remains untested across the animal tree of life. This lack of evidence has promoted the rise of alternative hypotheses arguing that sex differences are entirely driven by environmental factors or chance. We demonstrate that, across the animal kingdom, sexual selection, as captured by standard Bateman metrics, is indeed stronger in males than in females and that it is evolutionarily tied to sex biases in parental care and sexual dimorphism. Our findings provide the first comprehensive evidence that Darwin's concept of conventional sex roles is accurate and refute recent criticism of sexual selection theory.

  2. Geomagnetic polarity reversals as a mechanism for the punctuated equilibrium model of biological evolution

    International Nuclear Information System (INIS)

    Welsh, J.S.; Welsh, A.L.; Welsh, W.F.

    2003-01-01

    In contrast to what is predicted by classical Darwinian theory (phyletic gradualism), the fossil record typically displays a pattern of relatively sudden, dramatic changes as detailed by Eldregde and Gould's model of punctuated equilibrium. Evolutionary biologists have been at a loss to explain the ultimate source of the new mutations that drive evolution. One hypothesis holds that the abrupt speciation seen in the punctuated equilibrium model is secondary to an increased mutation rate resulting from periodically increased levels of ionizing radiation on the Earth's surface. Sporadic geomagnetic pole reversals, occurring every few million years on the average, are accompanied by alterations in the strength of the Earth's magnetic field and magnetosphere. This diminution may allow charged cosmic radiation to bombard Earth with less attenuation, thereby resulting in increased mutation rates. This episodic fluctuation in the magnetosphere is an attractive mechanism for the observed fossil record. Selected periods and epochs of geologic history for which data was available were reviewed for both geomagnetic pole reversal history and fossil record. Anomalies in either were scrutinized in greater depth and correlations were made. A 35 million year span (118-83 Ma) was identified during the Early/Middle Cretaceous period that was devoid of geomagnetic polarity reversals(the Cretaceous normal superchron). Examination of the fossil record (including several invertebrate and vertebrate taxons) during the Cretaceous normal superchron does not reveal any significant gap or slowing of speciation. Although increased terrestrial radiation exposure due to a diminution of the Earth's magnetosphere caused by a reversal of geomagnetic polarity is an attractive explanation for the mechanism of punctuated equilibrium, our investigation suggests that such polarity reversals cannot fully provide the driving force behind biological evolution. Further research is required to determine if

  3. Charles Darwin's Reception in Germany and What Followed.

    Directory of Open Access Journals (Sweden)

    Axel Meyer

    2009-07-01

    Full Text Available 150 years ago, Heinrich Bronn provided in the first German translation of Charles Darwin's Origin of Species a rather liberal interpretation, even adding his own view of Darwin's ideas in an additional 15th chapter. Ernst Haeckel widely popularized his view of Darwinian evolution based on his reading of this translation. This was long seen - probably incorrectly - as the intellectual root of social Darwinism in Germany.

  4. From Homo Sapiens to Homo Cosmicus - Astronautics, Darwinism abd Historical Determinism

    Science.gov (United States)

    Tolkowsky, G.

    Since its inception in late-nineteenth century, astronautics has been viewed as a historical outcome of human evolution as well as a future driver thereof. The history of astronautics-related, evolutionary thought reveals a tension between the Darwinian notion of natural selection and that of homocosmic predestination - be it of dialectical materialistic or theological nature. One can detect the influence of this ideological diversity on the American and Soviet space programs.

  5. Modelling sediment dynamics due to hillslope-river interactions : incorporating fluvial behaviour in landscape evolution model LAPSUS

    NARCIS (Netherlands)

    Baartman, Jantiene E. M.; van Gorp, Wouter; Temme, Arnaud J. A. M.; Schoorl, Jeroen M.

    Landscape evolution models (LEMs) simulate the three-dimensional development of landscapes over time. Different LEMs have different foci, e.g. erosional behaviour, river dynamics, the fluvial domain, hillslopes or a combination. LEM LAPSUS is a relatively simple cellular model operating on

  6. Transumanesimo, enhancement ed evoluzione. Riflessioni preliminari per una ridefinizione critica

    Directory of Open Access Journals (Sweden)

    LO SAPIO, LUCA

    2016-12-01

    Full Text Available Transhumanism, enhancement and evolution. Preliminary reflections for a critical redefinition This paper aims at focusing some possible uses of evolutionary theory in transhumanist authors. In particular it is analysed the evolutionary heuristics discussed by Nick Bostrom and Anders Sandberg, the proposal of a moral bioenhancement in Julian Savulescu and Ingmar Persson and the idea itself of a self-direct evolution based on the assumption of a self-guided selection of men’s features. These ideas are discussed to bring out the critical elements which are present in some uses of a presumably Darwinian framework in transhumanist approach.

  7. The critical roles of information and nonequilibrium thermodynamics in evolution of living systems.

    Science.gov (United States)

    Gatenby, Robert A; Frieden, B Roy

    2013-04-01

    Living cells are spatially bounded, low entropy systems that, although far from thermodynamic equilibrium, have persisted for billions of years. Schrödinger, Prigogine, and others explored the physical principles of living systems primarily in terms of the thermodynamics of order, energy, and entropy. This provided valuable insights, but not a comprehensive model. We propose the first principles of living systems must include: (1) Information dynamics, which permits conversion of energy to order through synthesis of specific and reproducible, structurally-ordered components; and (2) Nonequilibrium thermodynamics, which generate Darwinian forces that optimize the system.Living systems are fundamentally unstable because they exist far from thermodynamic equilibrium, but this apparently precarious state allows critical response that includes: (1) Feedback so that loss of order due to environmental perturbations generate information that initiates a corresponding response to restore baseline state. (2) Death due to a return to thermodynamic equilibrium to rapidly eliminate systems that cannot maintain order in local conditions. (3) Mitosis that rewards very successful systems, even when they attain order that is too high to be sustainable by environmental energy, by dividing so that each daughter cell has a much smaller energy requirement. Thus, nonequilibrium thermodynamics are ultimately responsible for Darwinian forces that optimize system dynamics, conferring robustness sufficient to allow continuous existence of living systems over billions of years.

  8. Rapid evolution and copy number variation of primate RHOXF2, an X-linked homeobox gene involved in male reproduction and possibly brain function.

    Science.gov (United States)

    Niu, Ao-lei; Wang, Yin-qiu; Zhang, Hui; Liao, Cheng-hong; Wang, Jin-kai; Zhang, Rui; Che, Jun; Su, Bing

    2011-10-12

    Darwinian positive selection acting on the male reproductive system and possibly also on the central nervous system, which sheds light on understanding the role of homeobox genes in adaptive evolution.

  9. Rapid evolution and copy number variation of primate RHOXF2, an X-linked homeobox gene involved in male reproduction and possibly brain function

    Directory of Open Access Journals (Sweden)

    Zhang Rui

    2011-10-01

    evolution and copy number changes of RHOXF2 had been driven by Darwinian positive selection acting on the male reproductive system and possibly also on the central nervous system, which sheds light on understanding the role of homeobox genes in adaptive evolution.

  10. Simulation of Corrosion Process for Structure with the Cellular Automata Method

    Science.gov (United States)

    Chen, M. C.; Wen, Q. Q.

    2017-06-01

    In this paper, from the mesoscopic point of view, under the assumption of metal corrosion damage evolution being a diffusive process, the cellular automata (CA) method was proposed to simulate numerically the uniform corrosion damage evolution of outer steel tube of concrete filled steel tubular columns subjected to corrosive environment, and the effects of corrosive agent concentration, dissolution probability and elapsed etching time on the corrosion damage evolution were also investigated. It was shown that corrosion damage increases nonlinearly with increasing elapsed etching time, and the longer the etching time, the more serious the corrosion damage; different concentration of corrosive agents had different impacts on the corrosion damage degree of the outer steel tube, but the difference between the impacts was very small; the heavier the concentration, the more serious the influence. The greater the dissolution probability, the more serious the corrosion damage of the outer steel tube, but with the increase of dissolution probability, the difference between its impacts on the corrosion damage became smaller and smaller. To validate present method, corrosion damage measurements for concrete filled square steel tubular columns (CFSSTCs) sealed at both their ends and immersed fully in a simulating acid rain solution were conducted, and Faraday’s law was used to predict their theoretical values. Meanwhile, the proposed CA mode was applied for the simulation of corrosion damage evolution of the CFSSTCs. It was shown by the comparisons of results from the three methods aforementioned that they were in good agreement, implying that the proposed method used for the simulation of corrosion damage evolution of concrete filled steel tubular columns is feasible and effective. It will open a new approach to study and evaluate further the corrosion damage, loading capacity and lifetime prediction of concrete filled steel tubular structures.

  11. The Physics of Open Ended Evolution

    Science.gov (United States)

    Adams, Alyssa M.

    What makes living systems different than non-living ones? Unfortunately this question is impossible to answer, at least currently. Instead, we must face computationally tangible questions based on our current understanding of physics, computation, information, and biology. Yet we have few insights into how living systems might quantifiably differ from their non-living counterparts, as in a mathematical foundation to explain away our observations of biological evolution, emergence, innovation, and organization. The development of a theory of living systems, if at all possible, demands a mathematical understanding of how data generated by complex biological systems changes over time. In addition, this theory ought to be broad enough as to not be constrained to an Earth-based biochemistry. In this dissertation, the philosophy of studying living systems from the perspective of traditional physics is first explored as a motivating discussion for subsequent research. Traditionally, we have often thought of the physical world from a bottom-up approach: things happening on a smaller scale aggregate into things happening on a larger scale. In addition, the laws of physics are generally considered static over time. Research suggests that biological evolution may follow dynamic laws that (at least in part) change as a function of the state of the system. Of the three featured research projects, cellular automata (CA) are used as a model to study certain aspects of living systems in two of them. These aspects include self-reference, open-ended evolution, local physical universality, subjectivity, and information processing. Open-ended evolution and local physical universality are attributed to the vast amount of innovation observed throughout biological evolution. Biological systems may distinguish themselves in terms of information processing and storage, not outside the theory of computation. The final research project concretely explores real-world phenomenon by means of

  12. Dynamic behavior of cellular materials and cellular structures: Experiments and modeling

    Science.gov (United States)

    Gao, Ziyang

    Cellular solids, including cellular materials and cellular structures (CMS), have attracted people's great interests because of their low densities and novel physical, mechanical, thermal, electrical and acoustic properties. They offer potential for lightweight structures, energy absorption, thermal management, etc. Therefore, the studies of cellular solids have become one of the hottest research fields nowadays. From energy absorption point of view, any plastically deformed structures can be divided into two types (called type I and type II), and the basic cells of the CMS may take the configurations of these two types of structures. Accordingly, separated discussions are presented in this thesis. First, a modified 1-D model is proposed and numerically solved for a typical type II structure. Good agreement is achieved with the previous experimental data, hence is used to simulate the dynamic behavior of a type II chain. Resulted from different load speeds, interesting collapse modes are observed, and the parameters which govern the cell's post-collapse behavior are identified through a comprehensive non-dimensional analysis on general cellular chains. Secondly, the MHS specimens are chosen as an example of type I foam materials because of their good uniformity of the cell geometry. An extensive experimental study was carried out, where more attention was paid to their responses to dynamic loadings. Great enhancement of the stress-strain curve was observed in dynamic cases, and the energy absorption capacity is found to be several times higher than that of the commercial metal foams. Based on the experimental study, finite elemental simulations and theoretical modeling are also conducted, achieving good agreements and demonstrating the validities of those models. It is believed that the experimental, numerical and analytical results obtained in the present study will certainly deepen the understanding of the unsolved fundamental issues on the mechanical behavior of

  13. Cellular Metabolic Rate Is Influenced by Life-History Traits in Tropical and Temperate Birds

    Science.gov (United States)

    Jimenez, Ana Gabriela; Van Brocklyn, James; Wortman, Matthew; Williams, Joseph B.

    2014-01-01

    In general, tropical birds have a “slow pace of life,” lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR), proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR]), using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal’s life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species. PMID:24498080

  14. An evolution-based strategy for engineering allosteric regulation

    Science.gov (United States)

    Pincus, David; Resnekov, Orna; Reynolds, Kimberly A.

    2017-04-01

    Allosteric regulation provides a way to control protein activity at the time scale of milliseconds to seconds inside the cell. An ability to engineer synthetic allosteric systems would be of practical utility for the development of novel biosensors, creation of synthetic cell signaling pathways, and design of small molecule pharmaceuticals with regulatory impact. To this end, we outline a general approach—termed rational engineering of allostery at conserved hotspots (REACH)—to introduce novel regulation into a protein of interest by exploiting latent allostery that has been hard-wired by evolution into its structure. REACH entails the use of statistical coupling analysis (SCA) to identify ‘allosteric hotspots’ on protein surfaces, the development and implementation of experimental assays to test hotspots for functionality, and a toolkit of allosteric modulators to impinge on endogenous cellular circuitry. REACH can be broadly applied to rewire cellular processes to respond to novel inputs.

  15. Smart Bandwidth Assignation in an Underlay Cellular Network for Internet of Vehicles.

    Science.gov (United States)

    de la Iglesia, Idoia; Hernandez-Jayo, Unai; Osaba, Eneko; Carballedo, Roberto

    2017-09-27

    The evolution of the IoT (Internet of Things) paradigm applied to new scenarios as VANETs (Vehicular Ad Hoc Networks) has gained momentum in recent years. Both academia and industry have triggered advanced studies in the IoV (Internet of Vehicles), which is understood as an ecosystem where different types of users (vehicles, elements of the infrastructure, pedestrians) are connected. How to efficiently share the available radio resources among the different types of eligible users is one of the important issues to be addressed. This paper briefly analyzes various concepts presented hitherto in the literature and it proposes an enhanced algorithm for ensuring a robust co-existence of the aforementioned system users. Therefore, this paper introduces an underlay RRM (Radio Resource Management) methodology which is capable of (1) improving cellular spectral efficiency while making a minimal impact on cellular communications and (2) ensuring the different QoS (Quality of Service) requirements of ITS (Intelligent Transportation Systems) applications. Simulation results, where we compare the proposed algorithm to the other two RRM, show the promising spectral efficiency performance of the proposed RRM methodology.

  16. Making a Theist out of Darwin: Asa Gray's Post-Darwinian Natural Theology

    Science.gov (United States)

    Hunter, T. Russell

    2012-01-01

    In March of 1860 the eminent Harvard Botanist and orthodox Christian Asa Gray began promoting the Origin of Species in hopes of securing a fair examination of Darwin's evolutionary theory among theistic naturalists. To this end, Gray sought to demonstrate that Darwin had not written atheistically and that his theory of evolution by natural…

  17. Evolution of microbes and viruses: A paradigm shift in evolutionary biology?

    Directory of Open Access Journals (Sweden)

    Eugene V. Koonin

    2012-09-01

    Full Text Available When Charles Darwin formulated the central principles of evolutionary biology in the Origin of Species in 1859 and the architects of the Modern Synthesis integrated these principles with population genetics almost a century later, the principal if not the sole objects of evolutionary biology were multicellular eukaryotes, primarily animals and plants. Before the advent of efficient gene sequencing, all attempts to extend evolutionary studies to bacteria have been futile. Sequencing of the rRNA genes in thousands of microbes allowed the construction of the three- domain ‘ribosomal Tree of Life’ that was widely thought to have resolved the evolutionary relationships between the cellular life forms. However, subsequent massive sequencing of numerous, complete microbial genomes revealed novel evolutionary phenomena, the most fundamental of these being: i pervasive horizontal gene transfer (HGT, in large part mediated by viruses and plasmids, that shapes the genomes of archaea and bacteria and call for a radical revision (if not abandonment of the Tree of Life concept, ii Lamarckian-type inheritance that appears to be critical for antivirus defense and other forms of adaptation in prokaryotes, and iii evolution of evolvability, i.e. dedicated mechanisms for evolution such as vehicles for HGT and stress-induced mutagenesis systems. In the non-cellular part of the microbial world, phylogenomics and metagenomics of viruses and related selfish genetic elements revealed enormous genetic and molecular diversity and extremely high abundance of viruses that come across as the dominant biological entities on earth. Furthermore, the perennial arms race between viruses and their hosts is one of the defining factors of evolution. Thus, microbial phylogenomics adds new dimensions to the fundamental picture of evolution even as the principle of descent with modification discovered by Darwin and the laws of population genetics remain at the core of evolutionary

  18. MSAT and cellular hybrid networking

    Science.gov (United States)

    Baranowsky, Patrick W., II

    Westinghouse Electric Corporation is developing both the Communications Ground Segment and the Series 1000 Mobile Phone for American Mobile Satellite Corporation's (AMSC's) Mobile Satellite (MSAT) system. The success of the voice services portion of this system depends, to some extent, upon the interoperability of the cellular network and the satellite communication circuit switched communication channels. This paper will describe the set of user-selectable cellular interoperable modes (cellular first/satellite second, etc.) provided by the Mobile Phone and described how they are implemented with the ground segment. Topics including roaming registration and cellular-to-satellite 'seamless' call handoff will be discussed, along with the relevant Interim Standard IS-41 Revision B Cellular Radiotelecommunications Intersystem Operations and IOS-553 Mobile Station - Land Station Compatibility Specification.

  19. The cellular immune response of Daphnia magna under host-parasite genetic variation and variation in initial dose.

    Science.gov (United States)

    Auld, Stuart K J R; Edel, Kai H; Little, Tom J

    2012-10-01

    In invertebrate-parasite systems, the likelihood of infection following parasite exposure is often dependent on the specific combination of host and parasite genotypes (termed genetic specificity). Genetic specificity can maintain diversity in host and parasite populations and is a major component of the Red Queen hypothesis. However, invertebrate immune systems are thought to only distinguish between broad classes of parasite. Using a natural host-parasite system with a well-established pattern of genetic specificity, the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa, we found that only hosts from susceptible host-parasite genetic combinations mounted a cellular response following exposure to the parasite. These data are compatible with the hypothesis that genetic specificity is attributable to barrier defenses at the site of infection (the gut), and that the systemic immune response is general, reporting the number of parasite spores entering the hemocoel. Further supporting this, we found that larger cellular responses occurred at higher initial parasite doses. By studying the natural infection route, where parasites must pass barrier defenses before interacting with systemic immune responses, these data shed light on which components of invertebrate defense underlie genetic specificity. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  20. Evolution of microstructure in laser welding of SS304L

    International Nuclear Information System (INIS)

    Kumar, Santosh; Kushwaha, R.P.; Viswanadham, C.S.; Dey, G.K.

    2009-01-01

    Laser welding is an important joining process and its application in industries is growing rapidly. One can produce laser welds over a wide range of process parameters and this offers very good opportunity for producing microstructure of different morphology and scales in the weldment. Weld beads have been produced on 5 mm thick plates of SS304L using CW Nd-YAG laser. Laser power was varied in 200 W to 1000 W range and welding speed was varied in 100 mm/mm to 1000 mm/mm. This resulted in weld beads of different morphology. Microstructure of the weld beads was examined on the cross-section as well as in the axial direction using optical microscopy and Transmission Electron Microscopy (TEM) to study evolution of the microstructure in the weldment. Microstructure was cellular and cellular-dendritic with grains growing from the fusion line towards the centerline. In the central region, cellular growth along the welding direction was observed. The cell size was found to increase with increasing laser power and decreasing welding speed. The findings are presented in this paper. (author)

  1. Top-down cellular pyramids

    Energy Technology Data Exchange (ETDEWEB)

    Wu, A Y; Rosenfeld, A

    1983-10-01

    A cellular pyramid is an exponentially tapering stack of arrays of processors (cells), where each cell is connected to its neighbors (siblings) on its own level, to a parent on the level above, and to its children on the level below. It is shown that in some situations, if information flows top-down only, from fathers to sons, then a cellular pyramid may be no faster than a one-level cellular array; but it may be possible to use simpler cells in the pyramid case. 23 references.

  2. Cellular decomposition in vikalloys

    International Nuclear Information System (INIS)

    Belyatskaya, I.S.; Vintajkin, E.Z.; Georgieva, I.Ya.; Golikov, V.A.; Udovenko, V.A.

    1981-01-01

    Austenite decomposition in Fe-Co-V and Fe-Co-V-Ni alloys at 475-600 deg C is investigated. The cellular decomposition in ternary alloys results in the formation of bcc (ordered) and fcc structures, and in quaternary alloys - bcc (ordered) and 12R structures. The cellular 12R structure results from the emergence of stacking faults in the fcc lattice with irregular spacing in four layers. The cellular decomposition results in a high-dispersion structure and magnetic properties approaching the level of well-known vikalloys [ru

  3. Character evolution and missing (morphological) data across Asteridae.

    Science.gov (United States)

    Stull, Gregory W; Schori, Melanie; Soltis, Douglas E; Soltis, Pamela S

    2018-04-14

    Our current understanding of flowering plant phylogeny provides an excellent framework for exploring various aspects of character evolution through comparative analyses. However, attempts to synthesize this phylogenetic framework with extensive morphological data sets have been surprisingly rare. Here, we explore character evolution in Asteridae (asterids), a major angiosperm clade, using an extensive morphological data set and a well-resolved phylogeny. We scored 15 phenotypic characters (spanning chemistry, vegetative anatomy, and floral, fruit, and seed features) across 248 species for ancestral state reconstruction using a phylogenetic framework based on 73 plastid genes and the same 248 species. Iridoid production, unitegmic ovules, and cellular endosperm were all reconstructed as synapomorphic for Asteridae. Sympetaly, long associated with asterids, shows complex patterns of evolution, suggesting it arose several times independently within the clade. Stamens equal in number to the petals is likely a synapomorphy for Gentianidae, a major asterid subclade. Members of Lamianae, a major gentianid subclade, are potentially diagnosed by adnate stamens, unilacunar nodes, and simple perforation plates. The analyses presented here provide a greatly improved understanding of character evolution across Asteridae, highlighting multiple characters potentially synapomorphic for major clades. However, several important parts of the asterid tree are poorly known for several key phenotypic features (e.g., degree of petal fusion, integument number, nucellus type, endosperm type, iridoid production). Further morphological, anatomical, developmental, and chemical investigations of these poorly known asterids are critical for a more detailed understanding of early asterid evolution. © 2018 Botanical Society of America.

  4. Causa Memetika

    OpenAIRE

    Knedla, Dalibor

    2011-01-01

    This bachelor thesis focuses on the controversial topic of memetics. Memetics is rather new science which links sociology, biology and psychology together. The central aim of memetics is to explain the cultural transfer, using the Darwinian concepts of evolution. The thesis is divided into three chapters. Each chapter deals with the different perspective of the memetic theory. The first chapter describes the theory itself and foundations of the theory, the second chapter describes problematic...

  5. An Evolutionary Framework for Understanding the Origin of Eukaryotes

    OpenAIRE

    Neil W. Blackstone

    2016-01-01

    Two major obstacles hinder the application of evolutionary theory to the origin of eukaryotes. The first is more apparent than real?the endosymbiosis that led to the mitochondrion is often described as ?non-Darwinian? because it deviates from the incremental evolution championed by the modern synthesis. Nevertheless, endosymbiosis can be accommodated by a multi-level generalization of evolutionary theory, which Darwin himself pioneered. The second obstacle is more serious?all of the major fea...

  6. From the social learning theory to a social learning algorithm for global optimization

    OpenAIRE

    Gong, Yue-Jiao; Zhang, Jun; Li, Yun

    2014-01-01

    Traditionally, the Evolutionary Computation (EC) paradigm is inspired by Darwinian evolution or the swarm intelligence of animals. Bandura's Social Learning Theory pointed out that the social learning behavior of humans indicates a high level of intelligence in nature. We found that such intelligence of human society can be implemented by numerical computing and be utilized in computational algorithms for solving optimization problems. In this paper, we design a novel and generic optimization...

  7. Review series on helminths, immune modulation and the hygiene hypothesis: the broader implications of the hygiene hypothesis.

    Science.gov (United States)

    Rook, Graham A W

    2009-01-01

    Man has moved rapidly from the hunter-gatherer environment to the living conditions of the rich industrialized countries. The hygiene hypothesis suggests that the resulting changed and reduced pattern of exposure to microorganisms has led to disordered regulation of the immune system, and hence to increases in certain inflammatory disorders. The concept began with the allergic disorders, but there are now good reasons for extending it to autoimmunity, inflammatory bowel disease, neuroinflammatory disorders, atherosclerosis, depression associated with raised inflammatory cytokines, and some cancers. This review discusses these possibilities in the context of Darwinian medicine, which uses knowledge of evolution to cast light on human diseases. The Darwinian approach enables one to correctly identify some of the organisms that are important for the 'Hygiene' or 'Old Friends' hypothesis, and to point to the potential exploitation of these organisms or their components in novel types of prophylaxis with applications in several branches of medicine.

  8. The evolution of violence in men: the function of central cholesterol and serotonin.

    Science.gov (United States)

    Wallner, Bernard; Machatschke, Ivo H

    2009-04-30

    Numerous studies point to central serotonin as an important modulator of maladaptive behaviors. In men, for instance, low concentrations of this neurotransmitter are related to hostile aggression. A key player in serotonin metabolism seems to be central cholesterol. It plays a fundamental role in maintaining the soundness of neuron membranes, especially in the exocytosis transport of serotonin vesicles into the synaptic cleft. In this review, we attempt an evolutionary approach to the neurobiological basis of human male violence. Hominid evolution was shaped by periods of starvation but also by energy demands of an increasingly complex brain. A lack of food resources reduces uptake of glucose and results in a decreased energy-supply for autonomous brain cholesterol synthesis. Consequently, concentrations of neuromembrane cholesterol decrease, which lead to a failure of the presynaptic re-uptake mechanism of serotonin and ultimately to low central serotonin. We propose that starvation might have affected the larger male brains earlier than those of females. Furthermore, this neurophysiological process diminished the threshold for hostile aggression, which in effect represented a prerequisite for being a successful hunter or scavenger. In a Darwinian sense, the odds to acquire reliable energetic resources made those males to attractive spouses in terms of paternal care and mate support. To underpin these mechanisms, a hypothetical four-stage model of synaptic membrane destabilization effected by a prolonged shortage of high-energy, cholesterol-containing food is illustrated.

  9. Cellular automata analysis and applications

    CERN Document Server

    Hadeler, Karl-Peter

    2017-01-01

    This book focuses on a coherent representation of the main approaches to analyze the dynamics of cellular automata. Cellular automata are an inevitable tool in mathematical modeling. In contrast to classical modeling approaches as partial differential equations, cellular automata are straightforward to simulate but hard to analyze. In this book we present a review of approaches and theories that allow the reader to understand the behavior of cellular automata beyond simulations. The first part consists of an introduction of cellular automata on Cayley graphs, and their characterization via the fundamental Cutis-Hedlund-Lyndon theorems in the context of different topological concepts (Cantor, Besicovitch and Weyl topology). The second part focuses on classification results: What classification follows from topological concepts (Hurley classification), Lyapunov stability (Gilman classification), and the theory of formal languages and grammars (Kůrka classification). These classifications suggest to cluster cel...

  10. Gravity: one of the driving forces for evolution.

    Science.gov (United States)

    Volkmann, D; Baluska, F

    2006-12-01

    Mechanical load is 10(3) larger for land-living than for water-living organisms. As a consequence, antigravitational material in form of compound materials like lignified cell walls in plants and mineralised bones in animals occurs in land-living organisms preferentially. Besides cellulose, pectic substances of plant cell walls seem to function as antigravitational material in early phases of plant evolution and development. A testable hypothesis including vesicular recycling processes into the tensegrity concept is proposed for both sensing of gravitational force and responding by production of antigravitational material at the cellular level.

  11. Conflict RNA modification, host-parasite co-evolution, and the origins of DNA and DNA-binding proteins1.

    Science.gov (United States)

    McLaughlin, Paul J; Keegan, Liam P

    2014-08-01

    Nearly 150 different enzymatically modified forms of the four canonical residues in RNA have been identified. For instance, enzymes of the ADAR (adenosine deaminase acting on RNA) family convert adenosine residues into inosine in cellular dsRNAs. Recent findings show that DNA endonuclease V enzymes have undergone an evolutionary transition from cleaving 3' to deoxyinosine in DNA and ssDNA to cleaving 3' to inosine in dsRNA and ssRNA in humans. Recent work on dsRNA-binding domains of ADARs and other proteins also shows that a degree of sequence specificity is achieved by direct readout in the minor groove. However, the level of sequence specificity observed is much less than that of DNA major groove-binding helix-turn-helix proteins. We suggest that the evolution of DNA-binding proteins following the RNA to DNA genome transition represents the major advantage that DNA genomes have over RNA genomes. We propose that a hypothetical RNA modification, a RRAR (ribose reductase acting on genomic dsRNA) produced the first stretches of DNA in RNA genomes. We discuss why this is the most satisfactory explanation for the origin of DNA. The evolution of this RNA modification and later steps to DNA genomes are likely to have been driven by cellular genome co-evolution with viruses and intragenomic parasites. RNA modifications continue to be involved in host-virus conflicts; in vertebrates, edited cellular dsRNAs with inosine-uracil base pairs appear to be recognized as self RNA and to suppress activation of innate immune sensors that detect viral dsRNA.

  12. A mechano-biological model of multi-tissue evolution in bone

    Science.gov (United States)

    Frame, Jamie; Rohan, Pierre-Yves; Corté, Laurent; Allena, Rachele

    2017-12-01

    Successfully simulating tissue evolution in bone is of significant importance in predicting various biological processes such as bone remodeling, fracture healing and osseointegration of implants. Each of these processes involves in different ways the permanent or transient formation of different tissue types, namely bone, cartilage and fibrous tissues. The tissue evolution in specific circumstances such as bone remodeling and fracturing healing is currently able to be modeled. Nevertheless, it remains challenging to predict which tissue types and organization can develop without any a priori assumptions. In particular, the role of mechano-biological coupling in this selective tissue evolution has not been clearly elucidated. In this work, a multi-tissue model has been created which simultaneously describes the evolution of bone, cartilage and fibrous tissues. The coupling of the biological and mechanical factors involved in tissue formation has been modeled by defining two different tissue states: an immature state corresponding to the early stages of tissue growth and representing cell clusters in a weakly neo-formed Extra Cellular Matrix (ECM), and a mature state corresponding to well-formed connective tissues. This has allowed for the cellular processes of migration, proliferation and apoptosis to be described simultaneously with the changing ECM properties through strain driven diffusion, growth, maturation and resorption terms. A series of finite element simulations were carried out on idealized cantilever bending geometries. Starting from a tissue composition replicating a mid-diaphysis section of a long bone, a steady-state tissue formation was reached over a statically loaded period of 10,000 h (60 weeks). The results demonstrated that bone formation occurred in regions which are optimally physiologically strained. In two additional 1000 h bending simulations both cartilaginous and fibrous tissues were shown to form under specific geometrical and loading

  13. Androgenic signaling systems and their role in behavioral evolution.

    Science.gov (United States)

    Fuxjager, Matthew J; Schuppe, Eric R

    2018-06-05

    Sex steroids mediate the organization and activation of masculine reproductive phenotypes in diverse vertebrate taxa. However, the effects of sex steroid action in this context vary tremendously, in that steroid action influences reproductive physiology and behavior in markedly different ways (even among closely related species). This leads to the idea that the mechanisms underlying sex steroid action similarly differ across vertebrates in a manner that supports diversification of important sexual traits. Here, we highlight the Evolutionary Potential Hypothesis as a framework for understanding how androgen-dependent reproductive behavior evolves. This idea posits that the cellular mechanisms underlying androgenic action can independently evolve within a given target tissue to adjust the hormone's functional effects. The result is a seemingly endless number of permutations in androgenic signaling pathways that can be mapped onto the incredible diversity of reproductive phenotypes. One reason this hypothesis is important is because it shifts current thinking about the evolution of steroid-dependent traits away from an emphasis on circulating steroid levels and toward a focus on molecular mechanisms of hormone action. To this end, we also provide new empirical data suggesting that certain cellular modulators of androgen action-namely, the co-factors that dynamically adjust transcritpional effects of steroid action either up or down-are also substrates on which evolution can act. We then close the review with a detailed look at a case study in the golden-collared manakin (Manacus vitellinus). Work in this tropical bird shows how androgenic signaling systems are modified in specific parts of the skeletal muscle system to enhance motor performance necessary to produce acrobatic courtship displays. Altogether, this paper seeks to develop a platform to better understand how steroid action influences the evolution of complex animal behavior. Copyright © 2018 Elsevier Ltd

  14. Hybrid Off-Grid SPV/WTG Power System for Remote Cellular Base Stations Towards Green and Sustainable Cellular Networks in South Korea

    Directory of Open Access Journals (Sweden)

    Mohammed H. Alsharif

    2016-12-01

    Full Text Available This paper aims to address the sustainability of power resources and environmental conditions for telecommunication base stations (BSs at off-grid sites. Accordingly, this study examined the feasibility of using a hybrid solar photovoltaic (SPV/wind turbine generator (WTG system to feed the remote Long Term Evolution-macro base stations at off-grid sites of South Korea the energy necessary to minimise both the operational expenditure and greenhouse gas emissions. Three key aspects have been discussed: (i optimal system architecture; (ii energy yield analysis; and (iii economic analysis. In addition, this study compares the feasibility of using a hybrid SPV/WTG system vs. a diesel generator. The simulation results show that by applying the proposed SPV/WTG system scheme to the cellular system, the total operational expenditure can be up to 48.52% more efficient and sustainability can be ensured with better planning by providing cleaner energy.

  15. MIMO Communication for Cellular Networks

    CERN Document Server

    Huang, Howard; Venkatesan, Sivarama

    2012-01-01

    As the theoretical foundations of multiple-antenna techniques evolve and as these multiple-input multiple-output (MIMO) techniques become essential for providing high data rates in wireless systems, there is a growing need to understand the performance limits of MIMO in practical networks. To address this need, MIMO Communication for Cellular Networks presents a systematic description of MIMO technology classes and a framework for MIMO system design that takes into account the essential physical-layer features of practical cellular networks. In contrast to works that focus on the theoretical performance of abstract MIMO channels, MIMO Communication for Cellular Networks emphasizes the practical performance of realistic MIMO systems. A unified set of system simulation results highlights relative performance gains of different MIMO techniques and provides insights into how best to use multiple antennas in cellular networks under various conditions. MIMO Communication for Cellular Networks describes single-user,...

  16. Evolution based on domain combinations: the case of glutaredoxins

    Directory of Open Access Journals (Sweden)

    Herrero Enrique

    2009-03-01

    Full Text Available Abstract Background Protein domains represent the basic units in the evolution of proteins. Domain duplication and shuffling by recombination and fusion, followed by divergence are the most common mechanisms in this process. Such domain fusion and recombination events are predicted to occur only once for a given multidomain architecture. However, other scenarios may be relevant in the evolution of specific proteins, such as convergent evolution of multidomain architectures. With this in mind, we study glutaredoxin (GRX domains, because these domains of approximately one hundred amino acids are widespread in archaea, bacteria and eukaryotes and participate in fusion proteins. GRXs are responsible for the reduction of protein disulfides or glutathione-protein mixed disulfides and are involved in cellular redox regulation, although their specific roles and targets are often unclear. Results In this work we analyze the distribution and evolution of GRX proteins in archaea, bacteria and eukaryotes. We study over one thousand GRX proteins, each containing at least one GRX domain, from hundreds of different organisms and trace the origin and evolution of the GRX domain within the tree of life. Conclusion Our results suggest that single domain GRX proteins of the CGFS and CPYC classes have, each, evolved through duplication and divergence from one initial gene that was present in the last common ancestor of all organisms. Remarkably, we identify a case of convergent evolution in domain architecture that involves the GRX domain. Two independent recombination events of a TRX domain to a GRX domain are likely to have occurred, which is an exception to the dominant mechanism of domain architecture evolution.

  17. The evolution of ambulatory ECG monitoring.

    Science.gov (United States)

    Kennedy, Harold L

    2013-01-01

    Ambulatory Holter electrocardiographic (ECG) monitoring has undergone continuous technological evolution since its invention and development in the 1950s era. With commercial introduction in 1963, there has been an evolution of Holter recorders from 1 channel to 12 channel recorders with increasingly smaller storage media, and there has evolved Holter analysis systems employing increasingly technologically advanced electronics providing a myriad of data displays. This evolution of smaller physical instruments with increasing technological capacity has characterized the development of electronics over the past 50 years. Currently the technology has been focused upon the conventional continuous 24 to 48 hour ambulatory ECG examination, and conventional extended ambulatory monitoring strategies for infrequent to rare arrhythmic events. However, the emergence of the Internet, Wi-Fi, cellular networks, and broad-band transmission has positioned these modalities at the doorway of the digital world. This has led to an adoption of more cost-effective strategies to these conventional methods of performing the examination. As a result, the emergence of the mobile smartphone coupled with this digital capacity is leading to the recent development of Holter smartphone applications. The potential of point-of-care applications utilizing the Holter smartphone and a vast array of new non-invasive sensors is evident in the not too distant future. The Holter smartphone is anticipated to contribute significantly in the future to the field of global health. © 2013.

  18. Receptor-mediated endocytosis generates nanomechanical force reflective of ligand identity and cellular property.

    Science.gov (United States)

    Zhang, Xiao; Ren, Juan; Wang, Jingren; Li, Shixie; Zou, Qingze; Gao, Nan

    2018-08-01

    Whether environmental (thermal, chemical, and nutrient) signals generate quantifiable, nanoscale, mechanophysical changes in the cellular plasma membrane has not been well elucidated. Assessment of such mechanophysical properties of plasma membrane may shed lights on fundamental cellular process. Atomic force microscopic (AFM) measurement of the mechanical properties of live cells was hampered by the difficulty in accounting for the effects of the cantilever motion and the associated hydrodynamic force on the mechanical measurement. These challenges have been addressed in our recently developed control-based AFM nanomechanical measurement protocol, which enables a fast, noninvasive, broadband measurement of the real-time changes in plasma membrane elasticity in live cells. Here we show using this newly developed AFM platform that the plasma membrane of live mammalian cells exhibits a constant and quantifiable nanomechanical property, the membrane elasticity. This mechanical property sensitively changes in response to environmental factors, such as the thermal, chemical, and growth factor stimuli. We demonstrate that different chemical inhibitors of endocytosis elicit distinct changes in plasma membrane elastic modulus reflecting their specific molecular actions on the lipid configuration or the endocytic machinery. Interestingly, two different growth factors, EGF and Wnt3a, elicited distinct elastic force profiles revealed by AFM at the plasma membrane during receptor-mediated endocytosis. By applying this platform to genetically modified cells, we uncovered a previously unknown contribution of Cdc42, a key component of the cellular trafficking network, to EGF-stimulated endocytosis at plasma membrane. Together, this nanomechanical AFM study establishes an important foundation that is expandable and adaptable for investigation of cellular membrane evolution in response to various key extracellular signals. © 2017 Wiley Periodicals, Inc.

  19. Human more complex than mouse at cellular level.

    Directory of Open Access Journals (Sweden)

    Alexander E Vinogradov

    Full Text Available The family of transcription factors with the C2H2 zinc finger domain is expanding in the evolution of vertebrates, reaching its highest numbers in the mammals. The question arises: whether an increased amount of these transcription factors is related to embryogenesis, nervous system, pathology or more of them are expressed in individual cells? Among mammals, the primates have a more complex anatomical structure than the rodents (e.g., brain. In this work, I show that a greater number of C2H2-ZF genes are expressed in the human cells than in the mouse cells. The effect is especially pronounced for C2H2-ZF genes accompanied with the KRAB domain. The relative difference between the numbers of C2H2-ZF(-KRAB genes in the human and mouse cellular transcriptomes even exceeds their difference in the genomes (i.e. a greater subset of existing in the genome genes is expressed in the human cellular transcriptomes compared to the mouse transcriptomes. The evolutionary turnover of C2H2-ZF(-KRAB genes acts in the direction of the revealed phenomenon, i.e. gene duplication and loss enhances the difference in the relative number of C2H2-ZF(-KRAB genes between human and mouse cellular transcriptomes. A higher amount of these genes is expressed in the brain and embryonic cells (compared with other tissues, whereas a lower amount--in the cancer cells. It is specifically the C2H2-ZF transcription factors whose repertoire is poorer in the cancer and richer in the brain (other transcription factors taken together do not show this trend. These facts suggest that increase of anatomical complexity is accompanied by a more complex intracellular regulation involving these transcription factors. Malignization is associated with simplification of this regulation. These results agree with the known fact that human cells are more resistant to oncogenic transformation than mouse cells. The list of C2H2-ZF genes whose suppression might be involved in malignization is provided.

  20. Cellular communications a comprehensive and practical guide

    CERN Document Server

    Tripathi, Nishith

    2014-01-01

    Even as newer cellular technologies and standards emerge, many of the fundamental principles and the components of the cellular network remain the same. Presenting a simple yet comprehensive view of cellular communications technologies, Cellular Communications provides an end-to-end perspective of cellular operations, ranging from physical layer details to call set-up and from the radio network to the core network. This self-contained source forpractitioners and students represents a comprehensive survey of the fundamentals of cellular communications and the landscape of commercially deployed

  1. Magnetohydrodynamics cellular automata

    International Nuclear Information System (INIS)

    Hatori, Tadatsugu.

    1990-02-01

    There has been a renewal of interest in cellular automata, partly because they give an architecture for a special purpose computer with parallel processing optimized to solve a particular problem. The lattice gas cellular automata are briefly surveyed, which are recently developed to solve partial differential equations such as hydrodynamics or magnetohydrodynamics. A new model is given in the present paper to implement the magnetic Lorentz force in a more deterministic and local procedure than the previous one. (author)

  2. Magnetohydrodynamic cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Hatori, Tadatsugu [National Inst. for Fusion Science, Nagoya (Japan)

    1990-03-01

    There has been a renewal of interest in cellular automata, partly because they give an architecture for a special purpose computer with parallel processing optimized to solve a particular problem. The lattice gas cellular automata are briefly surveyed, which are recently developed to solve partial differential equations such as hydrodynamics or magnetohydrodynamics. A new model is given in the present paper to implement the magnetic Lorentz force in a more deterministic and local procedure than the previous one. (author).

  3. Magnetohydrodynamic cellular automata

    International Nuclear Information System (INIS)

    Hatori, Tadatsugu

    1990-01-01

    There has been a renewal of interest in cellular automata, partly because they give an architecture for a special purpose computer with parallel processing optimized to solve a particular problem. The lattice gas cellular automata are briefly surveyed, which are recently developed to solve partial differential equations such as hydrodynamics or magnetohydrodynamics. A new model is given in the present paper to implement the magnetic Lorentz force in a more deterministic and local procedure than the previous one. (author)

  4. Modeling cellular systems

    CERN Document Server

    Matthäus, Franziska; Pahle, Jürgen

    2017-01-01

    This contributed volume comprises research articles and reviews on topics connected to the mathematical modeling of cellular systems. These contributions cover signaling pathways, stochastic effects, cell motility and mechanics, pattern formation processes, as well as multi-scale approaches. All authors attended the workshop on "Modeling Cellular Systems" which took place in Heidelberg in October 2014. The target audience primarily comprises researchers and experts in the field, but the book may also be beneficial for graduate students.

  5. [August Weismann's concept of germ plasma as the basic reason for the inadequacy of neo-Darwinism].

    Science.gov (United States)

    Grodnitskiĭ, D L

    2000-01-01

    Neo-Darwinism is a result of synthesis of Darwinian concept of natural selection with Weismannian concept of germ plasma. The concept of germ plasma is based on a hypothesis that phenotypic traits are completely determined by genes. Hence, neo-Darwinism describes evolution as a process of alternation of gene frequencies under the effect of natural selection. This is an inadequate approach to the study of evolution. In the course of evolution, genes change their functions, whereas phenotypic characters change their corresponding genes. As a result, every step of evolutionary transformation changes the structure of phenotype-to-genotype correspondence. Therefore, phenotypic evolution cannot be described in genetic terms, the same as to human languages cannot be translated one into another whenever the meaning of words is constantly changing. Consequently, Weismannian germ-plasma concept adequately describes the relation of characters to genes only during stasis, but is inapplicable to evolution.

  6. Time frames: the rethinking of Darwinian evolution and the theory of punctuated equilibria

    National Research Council Canada - National Science Library

    Eldredge, Niles

    1985-01-01

    .... Two eminent scientists, Niles Eldredge and Stephen Jay Gould, startled the world by challenging Darwin's cherished beliefs - proposing instead that once a species has evolved it rarely undergoes...

  7. Cellular Angiofibroma of the Nasopharynx.

    Science.gov (United States)

    Erdur, Zülküf Burak; Yener, Haydar Murat; Yilmaz, Mehmet; Karaaltin, Ayşegül Batioğlu; Inan, Hakki Caner; Alaskarov, Elvin; Gozen, Emine Deniz

    2017-11-01

    Angiofibroma is a common tumor of the nasopharynx region but cellular type is extremely rare in head and neck. A 13-year-old boy presented with frequent epistaxis and nasal obstruction persisting for 6 months. According to the clinical symptoms and imaging studies juvenile angiofibroma was suspected. Following angiographic embolization total excision of the lesion by midfacial degloving approach was performed. Histological examination revealed that the tumor consisted of staghorn blood vessels and irregular fibrous stroma. Stellate fibroblasts with small pyknotic to large vesicular nuclei were seen in a highly cellular stroma. These findings identified cellular angiofibroma mimicking juvenile angiofibroma. This article is about a very rare patient of cellular angiofibroma of nasopharynx.

  8. Assessment of general public exposure to lte signals compared to other cellular networks present in Thessaloniki, Greece

    International Nuclear Information System (INIS)

    Gkonis, Fotios; Boursianis, Achilles; Samaras, Theodoros

    2017-01-01

    To assess general public exposure to electromagnetic fields from Long Term Evolution (LTE) base stations, measurements at 10 sites in Thessaloniki, Greece were performed. Results are compared with other mobile cellular networks currently in use. All exposure values satisfy the guidelines for general public exposure of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), as well as the reference levels by the Greek legislation at all sites. LTE electric field measurements were recorded up to 0.645 V/m. By applying the ICNIRP guidelines, the exposure ratio for all LTE signals is between 2.9 x 10"-"5 and 2.8 x 10"-"2. From the measurements results it is concluded that the average and maximum power density contribution of LTE down-link signals to the overall cellular networks signals are 7.8% and 36.7%, respectively. (authors)

  9. A Model of Social Selection and Successful Altruism

    Science.gov (United States)

    1989-10-07

    D., The evolution of social behavior. Annual Reviews of Ecological Systems, 5:325-383 (1974). 2. Dawkins , R., The selfish gene . Oxford: Oxford...alive and well. it will be important to re- examine this striking historical experience,-not in terms o, oversimplified models of the " selfish gene ," but...Darwinian Analysis The acceptance by many modern geneticists of the axiom that the basic unit of selection Is the " selfish gene " quickly led to the

  10. 47 CFR 22.923 - Cellular system configuration.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Cellular system configuration. 22.923 Section... MOBILE SERVICES Cellular Radiotelephone Service § 22.923 Cellular system configuration. Mobile stations... directly or through cellular repeaters. Auxiliary test stations may communicate with base or mobile...

  11. Smart Bandwidth Assignation in an Underlay Cellular Network for Internet of Vehicles

    Directory of Open Access Journals (Sweden)

    Idoia de la Iglesia

    2017-09-01

    Full Text Available The evolution of the IoT (Internet of Things paradigm applied to new scenarios as VANETs (Vehicular Ad Hoc Networks has gained momentum in recent years. Both academia and industry have triggered advanced studies in the IoV (Internet of Vehicles, which is understood as an ecosystem where different types of users (vehicles, elements of the infrastructure, pedestrians are connected. How to efficiently share the available radio resources among the different types of eligible users is one of the important issues to be addressed. This paper briefly analyzes various concepts presented hitherto in the literature and it proposes an enhanced algorithm for ensuring a robust co-existence of the aforementioned system users. Therefore, this paper introduces an underlay RRM (Radio Resource Management methodology which is capable of (1 improving cellular spectral efficiency while making a minimal impact on cellular communications and (2 ensuring the different QoS (Quality of Service requirements of ITS (Intelligent Transportation Systems applications. Simulation results, where we compare the proposed algorithm to the other two RRM, show the promising spectral efficiency performance of the proposed RRM methodology.

  12. Recursive definition of global cellular-automata mappings

    International Nuclear Information System (INIS)

    Feldberg, R.; Knudsen, C.; Rasmussen, S.

    1994-01-01

    A method for a recursive definition of global cellular-automata mappings is presented. The method is based on a graphical representation of global cellular-automata mappings. For a given cellular-automaton rule the recursive algorithm defines the change of the global cellular-automaton mapping as the number of lattice sites is incremented. A proof of lattice size invariance of global cellular-automata mappings is derived from an approximation to the exact recursive definition. The recursive definitions are applied to calculate the fractal dimension of the set of reachable states and of the set of fixed points of cellular automata on an infinite lattice

  13. Mesoscale modeling and simulation of microstructure evolution during dynamic recrystallization of a Ni-based superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fei [University of Nottingham, Department of Mechanical, Materials and Manufacturing Engineering, Nottingham (United Kingdom); Shanghai Jiao Tong University, Institute of Forming Technology and Equipment, Shanghai (China); Cui, Zhenshan [Shanghai Jiao Tong University, Institute of Forming Technology and Equipment, Shanghai (China); Ou, Hengan [University of Nottingham, Department of Mechanical, Materials and Manufacturing Engineering, Nottingham (United Kingdom); Long, Hui [University of Sheffield, Department of Mechanical Engineering, Sheffield (United Kingdom)

    2016-10-15

    Microstructural evolution and plastic flow characteristics of a Ni-based superalloy were investigated using a simulative model that couples the basic metallurgical principle of dynamic recrystallization (DRX) with the two-dimensional (2D) cellular automaton (CA). Variation of dislocation density with local strain of deformation is considered for accurate determination of the microstructural evolution during DRX. The grain topography, the grain size and the recrystallized fraction can be well predicted by using the developed CA model, which enables to the establishment of the relationship between the flow stress, dislocation density, recrystallized fraction volume, recrystallized grain size and the thermomechanical parameters. (orig.)

  14. Discovering local patterns of co - evolution: computational aspects and biological examples

    Directory of Open Access Journals (Sweden)

    Tuller Tamir

    2010-01-01

    Full Text Available Abstract Background Co-evolution is the process in which two (or more sets of orthologs exhibit a similar or correlative pattern of evolution. Co-evolution is a powerful way to learn about the functional interdependencies between sets of genes and cellular functions and to predict physical interactions. More generally, it can be used for answering fundamental questions about the evolution of biological systems. Orthologs that exhibit a strong signal of co-evolution in a certain part of the evolutionary tree may show a mild signal of co-evolution in other branches of the tree. The major reasons for this phenomenon are noise in the biological input, genes that gain or lose functions, and the fact that some measures of co-evolution relate to rare events such as positive selection. Previous publications in the field dealt with the problem of finding sets of genes that co-evolved along an entire underlying phylogenetic tree, without considering the fact that often co-evolution is local. Results In this work, we describe a new set of biological problems that are related to finding patterns of local co-evolution. We discuss their computational complexity and design algorithms for solving them. These algorithms outperform other bi-clustering methods as they are designed specifically for solving the set of problems mentioned above. We use our approach to trace the co-evolution of fungal, eukaryotic, and mammalian genes at high resolution across the different parts of the corresponding phylogenetic trees. Specifically, we discover regions in the fungi tree that are enriched with positive evolution. We show that metabolic genes exhibit a remarkable level of co-evolution and different patterns of co-evolution in various biological datasets. In addition, we find that protein complexes that are related to gene expression exhibit non-homogenous levels of co-evolution across different parts of the fungi evolutionary line. In the case of mammalian evolution

  15. Cellular senescence and organismal aging.

    Science.gov (United States)

    Jeyapalan, Jessie C; Sedivy, John M

    2008-01-01

    Cellular senescence, first observed and defined using in vitro cell culture studies, is an irreversible cell cycle arrest which can be triggered by a variety of factors. Emerging evidence suggests that cellular senescence acts as an in vivo tumor suppression mechanism by limiting aberrant proliferation. It has also been postulated that cellular senescence can occur independently of cancer and contribute to the physiological processes of normal organismal aging. Recent data have demonstrated the in vivo accumulation of senescent cells with advancing age. Some characteristics of senescent cells, such as the ability to modify their extracellular environment, could play a role in aging and age-related pathology. In this review, we examine current evidence that links cellular senescence and organismal aging.

  16. Dracula's children: molecular evolution of vampire bat venom.

    Science.gov (United States)

    Low, Dolyce H W; Sunagar, Kartik; Undheim, Eivind A B; Ali, Syed A; Alagon, Alejandro C; Ruder, Tim; Jackson, Timothy N W; Pineda Gonzalez, Sandy; King, Glenn F; Jones, Alun; Antunes, Agostinho; Fry, Bryan G

    2013-08-26

    While vampire bat oral secretions have been the subject of intense research, efforts have concentrated only on two components: DSPA (Desmodus rotundus salivary plasminogen activator) and Draculin. The molecular evolutionary history of DSPA has been elucidated, while conversely draculin has long been known from only a very small fragment and thus even the basic protein class was not even established. Despite the fact that vampire bat venom has a multitude of effects unaccounted by the documented bioactivities of DSPA and draculin, efforts have not been made to establish what other bioactive proteins are secreted by their submaxillary gland. In addition, it has remained unclear whether the anatomically distinct anterior and posterior lobes of the submaxillary gland are evolving on separate gene expression trajectories or if they remain under the shared genetic control. Using a combined proteomic and transcriptomic approach, we show that identical proteins are simultaneously expressed in both lobes. In addition to recovering the known structural classes of DSPA, we recovered a novel DSPA isoform as well as obtained a very large sequence stretch of draculin and thus established that it is a mutated version of the lactotransferrin scaffold. This study reveals a much more complex secretion profile than previously recognised. In addition to obtaining novel versions of scaffolds convergently recruited into other venoms (allergen-like, CRiSP, kallikrein, Kunitz, lysozyme), we also documented novel expression of small peptides related to calcitonin, PACAP, and statherin. Other overexpressed protein types included BPI-fold, lacritin, and secretoglobin. Further, we investigate the molecular evolution of various vampire bat venom-components and highlight the dominant role of positive selection in the evolution of these proteins. Conspicuously many of the proteins identified in the proteome were found to be homologous to proteins with known activities affecting vasodilation and

  17. Precipitation-generated oscillations in open cellular cloud fields.

    Science.gov (United States)

    Feingold, Graham; Koren, Ilan; Wang, Hailong; Xue, Huiwen; Brewer, Wm Alan

    2010-08-12

    Cloud fields adopt many different patterns that can have a profound effect on the amount of sunlight reflected back to space, with important implications for the Earth's climate. These cloud patterns can be observed in satellite images of the Earth and often exhibit distinct cell-like structures associated with organized convection at scales of tens of kilometres. Recent evidence has shown that atmospheric aerosol particles-through their influence on precipitation formation-help to determine whether cloud fields take on closed (more reflective) or open (less reflective) cellular patterns. The physical mechanisms controlling the formation and evolution of these cells, however, are still poorly understood, limiting our ability to simulate realistically the effects of clouds on global reflectance. Here we use satellite imagery and numerical models to show how precipitating clouds produce an open cellular cloud pattern that oscillates between different, weakly stable states. The oscillations are a result of precipitation causing downward motion and outflow from clouds that were previously positively buoyant. The evaporating precipitation drives air down to the Earth's surface, where it diverges and collides with the outflows of neighbouring precipitating cells. These colliding outflows form surface convergence zones and new cloud formation. In turn, the newly formed clouds produce precipitation and new colliding outflow patterns that are displaced from the previous ones. As successive cycles of this kind unfold, convergence zones alternate with divergence zones and new cloud patterns emerge to replace old ones. The result is an oscillating, self-organized system with a characteristic cell size and precipitation frequency.

  18. Lymphocele: a possible relationship with acute cellular rejection in kidney transplantation

    Directory of Open Access Journals (Sweden)

    Marco Aurélio Silva Lipay

    1999-11-01

    Full Text Available CONTEXT: The incidence of lymphocele after renal transplantation varies between 0.6 and 18% of cases, and many factors have been associated to its etiology. Cellular rejection of the kidney allograft has been described as a possible causal factor of lymphocele. OBJECTIVE: To analyze the possible relationship between lymphocele and acute cellular rejection. DESIGN: A retrospective study. SETTING: A referral hospital center. SAMPLE: 170 patients submitted to kidney transplantation from March 1992 to January 1997. A standard technique for renal transplantation was used. RESULTS: Of the 19 patients that developed lymphocele, 16 presented at least one episode of acute cell rejection (84%, and were treated with methylprednisolone. The relation between lymphocele and rejection was statistically significant (p = 0.04. Treatment of lymphocele consisted of peritoneal marsupialization in 3 patients (15.3%, percutaneous drainage in 7 (36.8%, laparascopic marsupialization in 2 (10.5%, and conservative treatment in 7 patients (36.8%. Evolution was favorable in 15 patients (78.9%, 1 patient (5.3% died due to a cause unrelated to lymphocele, and 3 (15.8% lost the graft due to immunological factors. The average follow-up period was 24.5 months. CONCLUSION: The high incidence of acute cell rejection in patients with lymphocele suggests a possible causal relationship between both conditions.

  19. Validation of self-reported cellular phone use

    DEFF Research Database (Denmark)

    Samkange-Zeeb, Florence; Berg, Gabriele; Blettner, Maria

    2004-01-01

    BACKGROUND: In recent years, concern has been raised over possible adverse health effects of cellular telephone use. In epidemiological studies of cancer risk associated with the use of cellular telephones, the validity of self-reported cellular phone use has been problematic. Up to now there is ......BACKGROUND: In recent years, concern has been raised over possible adverse health effects of cellular telephone use. In epidemiological studies of cancer risk associated with the use of cellular telephones, the validity of self-reported cellular phone use has been problematic. Up to now...... there is very little information published on this subject. METHODS: We conducted a study to validate the questionnaire used in an ongoing international case-control study on cellular phone use, the "Interphone study". Self-reported cellular phone use from 68 of 104 participants who took part in our study...... was compared with information derived from the network providers over a period of 3 months (taken as the gold standard). RESULTS: Using Spearman's rank correlation, the correlation between self-reported phone use and information from the network providers for cellular phone use in terms of the number of calls...

  20. 47 CFR 90.672 - Unacceptable interference to non-cellular 800 MHz licensees from 800 MHz cellular systems or part...

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Unacceptable interference to non-cellular 800 MHz licensees from 800 MHz cellular systems or part 22 Cellular Radiotelephone systems, and within the... Procedures and Process-Unacceptable Interference § 90.672 Unacceptable interference to non-cellular 800 MHz...

  1. Origami interleaved tube cellular materials

    International Nuclear Information System (INIS)

    Cheung, Kenneth C; Tachi, Tomohiro; Calisch, Sam; Miura, Koryo

    2014-01-01

    A novel origami cellular material based on a deployable cellular origami structure is described. The structure is bi-directionally flat-foldable in two orthogonal (x and y) directions and is relatively stiff in the third orthogonal (z) direction. While such mechanical orthotropicity is well known in cellular materials with extruded two dimensional geometry, the interleaved tube geometry presented here consists of two orthogonal axes of interleaved tubes with high interfacial surface area and relative volume that changes with fold-state. In addition, the foldability still allows for fabrication by a flat lamination process, similar to methods used for conventional expanded two dimensional cellular materials. This article presents the geometric characteristics of the structure together with corresponding kinematic and mechanical modeling, explaining the orthotropic elastic behavior of the structure with classical dimensional scaling analysis. (paper)

  2. Origami interleaved tube cellular materials

    Science.gov (United States)

    Cheung, Kenneth C.; Tachi, Tomohiro; Calisch, Sam; Miura, Koryo

    2014-09-01

    A novel origami cellular material based on a deployable cellular origami structure is described. The structure is bi-directionally flat-foldable in two orthogonal (x and y) directions and is relatively stiff in the third orthogonal (z) direction. While such mechanical orthotropicity is well known in cellular materials with extruded two dimensional geometry, the interleaved tube geometry presented here consists of two orthogonal axes of interleaved tubes with high interfacial surface area and relative volume that changes with fold-state. In addition, the foldability still allows for fabrication by a flat lamination process, similar to methods used for conventional expanded two dimensional cellular materials. This article presents the geometric characteristics of the structure together with corresponding kinematic and mechanical modeling, explaining the orthotropic elastic behavior of the structure with classical dimensional scaling analysis.

  3. "How nationality influences Opinion": Darwinism and palaeontology in France (1859-1914).

    Science.gov (United States)

    Cohen, Claudine

    2017-12-01

    This paper discusses the "non-reception" of Darwin's works and concepts in French palaeontology and palaeoanthropology between 1859 and 1914. Indeed, this integration was difficult, biased and belated, for ideological, intellectual and epistemological reasons: Clémence Royer's biased 1862 translation of Darwin's Origin of Species pulled its ideas toward "social darwinism", making them less attractive to the natural sciences. - French nationalism and the authority of religion, which imposed Cuvier's thinking until late into the century - the dominance of Lamarckian and neo-Lamarckian transformism in France, both in biology and in paleontology, which proposed the notion of orthogenetic laws and environmental determinations, and refused darwinian evolutionary mechanisms - obstacles inherent to the application of Darwin's concepts to palaeontology, namely the impossibility to identify evolutionary mechanisms through the fossil record, which was stressed by Darwin himself and underlined in turn by 19th century French palaeontologists. However, as I argue, in the course of the examined period, French palaeontology grew from refusal to a better understanding and evaluation of Darwin's thinking. The quest for intermediary forms, the construction of branching evolutionary trees and the attempts to reconstruct human biological and cultural evolution were important efforts toward an integration of some aspects of Darwinian views and practices into French palaeontology and plaeoanthropology. The 1947 Paris conference which brought together American Neo-darwinists and French paleontologists made Darwinian concepts better understood and triggered a revival of French palaeontology from the 1960s. Copyright © 2017. Published by Elsevier Ltd.

  4. The Rise and Fall of an Evolutionary Innovation: Contrasting Strategies of Venom Evolution in Ancient and Young Animals.

    Science.gov (United States)

    Sunagar, Kartik; Moran, Yehu

    2015-10-01

    Animal venoms are theorized to evolve under the significant influence of positive Darwinian selection in a chemical arms race scenario, where the evolution of venom resistance in prey and the invention of potent venom in the secreting animal exert reciprocal selection pressures. Venom research to date has mainly focused on evolutionarily younger lineages, such as snakes and cone snails, while mostly neglecting ancient clades (e.g., cnidarians, coleoids, spiders and centipedes). By examining genome, venom-gland transcriptome and sequences from the public repositories, we report the molecular evolutionary regimes of several centipede and spider toxin families, which surprisingly accumulated low-levels of sequence variations, despite their long evolutionary histories. Molecular evolutionary assessment of over 3500 nucleotide sequences from 85 toxin families spanning the breadth of the animal kingdom has unraveled a contrasting evolutionary strategy employed by ancient and evolutionarily young clades. We show that the venoms of ancient lineages remarkably evolve under the heavy constraints of negative selection, while toxin families in lineages that originated relatively recently rapidly diversify under the influence of positive selection. We propose that animal venoms mostly employ a 'two-speed' mode of evolution, where the major influence of diversifying selection accompanies the earlier stages of ecological specialization (e.g., diet and range expansion) in the evolutionary history of the species-the period of expansion, resulting in the rapid diversification of the venom arsenal, followed by longer periods of purifying selection that preserve the potent toxin pharmacopeia-the period of purification and fixation. However, species in the period of purification may re-enter the period of expansion upon experiencing a major shift in ecology or environment. Thus, we highlight for the first time the significant roles of purifying and episodic selections in shaping animal

  5. The Rise and Fall of an Evolutionary Innovation: Contrasting Strategies of Venom Evolution in Ancient and Young Animals.

    Directory of Open Access Journals (Sweden)

    Kartik Sunagar

    2015-10-01

    Full Text Available Animal venoms are theorized to evolve under the significant influence of positive Darwinian selection in a chemical arms race scenario, where the evolution of venom resistance in prey and the invention of potent venom in the secreting animal exert reciprocal selection pressures. Venom research to date has mainly focused on evolutionarily younger lineages, such as snakes and cone snails, while mostly neglecting ancient clades (e.g., cnidarians, coleoids, spiders and centipedes. By examining genome, venom-gland transcriptome and sequences from the public repositories, we report the molecular evolutionary regimes of several centipede and spider toxin families, which surprisingly accumulated low-levels of sequence variations, despite their long evolutionary histories. Molecular evolutionary assessment of over 3500 nucleotide sequences from 85 toxin families spanning the breadth of the animal kingdom has unraveled a contrasting evolutionary strategy employed by ancient and evolutionarily young clades. We show that the venoms of ancient lineages remarkably evolve under the heavy constraints of negative selection, while toxin families in lineages that originated relatively recently rapidly diversify under the influence of positive selection. We propose that animal venoms mostly employ a 'two-speed' mode of evolution, where the major influence of diversifying selection accompanies the earlier stages of ecological specialization (e.g., diet and range expansion in the evolutionary history of the species-the period of expansion, resulting in the rapid diversification of the venom arsenal, followed by longer periods of purifying selection that preserve the potent toxin pharmacopeia-the period of purification and fixation. However, species in the period of purification may re-enter the period of expansion upon experiencing a major shift in ecology or environment. Thus, we highlight for the first time the significant roles of purifying and episodic selections

  6. Estimating cellular network performance during hurricanes

    International Nuclear Information System (INIS)

    Booker, Graham; Torres, Jacob; Guikema, Seth; Sprintson, Alex; Brumbelow, Kelly

    2010-01-01

    Cellular networks serve a critical role during and immediately after a hurricane, allowing citizens to contact emergency services when land-line communication is lost and serving as a backup communication channel for emergency responders. However, due to their ubiquitous deployment and limited design for extreme loading events, basic network elements, such as cellular towers and antennas are prone to failures during adverse weather conditions such as hurricanes. Accordingly, a systematic and computationally feasible approach is required for assessing and improving the reliability of cellular networks during hurricanes. In this paper we develop a new multi-disciplinary approach to efficiently and accurately assess cellular network reliability during hurricanes. We show how the performance of a cellular network during and immediately after future hurricanes can be estimated based on a combination of hurricane wind field models, structural reliability analysis, Monte Carlo simulation, and cellular network models and simulation tools. We then demonstrate the use of this approach for assessing the improvement in system reliability that can be achieved with discrete topological changes in the system. Our results suggest that adding redundancy, particularly through a mesh topology or through the addition of an optical fiber ring around the perimeter of the system can be an effective way to significantly increase the reliability of some cellular systems during hurricanes.

  7. Increasing the coverage area through relay node deployment in long term evolution advanced cellular networks

    Science.gov (United States)

    Aldhaibani, Jaafar A.; Ahmad, R. B.; Yahya, A.; Azeez, Suzan A.

    2015-05-01

    Wireless multi-hop relay networks have become very important technologies in mobile communications. These networks ensure high throughput and coverage extension with a low cost. The poor capacity at cell edges is not enough to meet with growing demand of high capacity and throughput irrespective of user's placement in the cellular network. In this paper we propose optimal placement of relay node that provides maximum achievable rate at users and enhances the throughput and coverage at cell edge region. The proposed scheme is based on the outage probability at users and taken on account the interference between nodes. Numerical analyses along with simulation results indicated there are an improvement in capacity for users at the cell edge is 40% increment from all cell capacity.

  8. The cellular memory disc of reprogrammed cells.

    Science.gov (United States)

    Anjamrooz, Seyed Hadi

    2013-04-01

    The crucial facts underlying the low efficiency of cellular reprogramming are poorly understood. Cellular reprogramming occurs in nuclear transfer, induced pluripotent stem cell (iPSC) formation, cell fusion, and lineage-switching experiments. Despite these advances, there are three fundamental problems to be addressed: (1) the majority of cells cannot be reprogrammed, (2) the efficiency of reprogramming cells is usually low, and (3) the reprogrammed cells developed from a patient's own cells activate immune responses. These shortcomings present major obstacles for using reprogramming approaches in customised cell therapy. In this Perspective, the author synthesises past and present observations in the field of cellular reprogramming to propose a theoretical picture of the cellular memory disc. The current hypothesis is that all cells undergo an endogenous and exogenous holographic memorisation such that parts of the cellular memory dramatically decrease the efficiency of reprogramming cells, act like a barrier against reprogramming in the majority of cells, and activate immune responses. Accordingly, the focus of this review is mainly to describe the cellular memory disc (CMD). Based on the present theory, cellular memory includes three parts: a reprogramming-resistance memory (RRM), a switch-promoting memory (SPM) and a culture-induced memory (CIM). The cellular memory arises genetically, epigenetically and non-genetically and affects cellular behaviours. [corrected].

  9. Handgrip Strength as a Darwinian Fitness Indicator in Men

    Directory of Open Access Journals (Sweden)

    Andrew C. Gallup

    2018-04-01

    Full Text Available Handgrip strength (HGS is a robust measure of overall muscular strength and function, and has long been predictive of a multitude of health factors and physical outcomes for both men and women. The fact that HGS represents such a ubiquitous measure of health and vitality may reflect the significance of this trait during human evolution. This trait is also highly sexually dimorphic due to influences of androgenic hormones and fat-free body mass, suggesting that it has been further elaborated through sexual selection. Consistent with this view, research within evolutionary psychology and related fields has documented distinct relationships between HGS and measures of social and sexual behavior, especially in men. Here, we review studies across different societies and cultural contexts showing that male HGS predicts measures of aggression and social dominance, perceived formidability, male-typical body morphology and movement, courtship display, physical attractiveness, and sexual behavior and reproductive fitness. These findings underscore the value of including HGS as an independent measure within studies examining human sexual selection, and corroborate existing research suggesting that specific features of physical strength have and continue to be under positive directional selection in men.

  10. Handgrip Strength as a Darwinian Fitness Indicator in Men.

    Science.gov (United States)

    Gallup, Andrew C; Fink, Bernhard

    2018-01-01

    Handgrip strength (HGS) is a robust measure of overall muscular strength and function, and has long been predictive of a multitude of health factors and physical outcomes for both men and women. The fact that HGS represents such a ubiquitous measure of health and vitality may reflect the significance of this trait during human evolution. This trait is also highly sexually dimorphic due to influences of androgenic hormones and fat-free body mass, suggesting that it has been further elaborated through sexual selection. Consistent with this view, research within evolutionary psychology and related fields has documented distinct relationships between HGS and measures of social and sexual behavior, especially in men. Here, we review studies across different societies and cultural contexts showing that male HGS predicts measures of aggression and social dominance, perceived formidability, male-typical body morphology and movement, courtship display, physical attractiveness, and sexual behavior and reproductive fitness. These findings underscore the value of including HGS as an independent measure within studies examining human sexual selection, and corroborate existing research suggesting that specific features of physical strength have and continue to be under positive directional selection in men.

  11. Cosserat modeling of cellular solids

    NARCIS (Netherlands)

    Onck, P.R.

    Cellular solids inherit their macroscopic mechanical properties directly from the cellular microstructure. However, the characteristic material length scale is often not small compared to macroscopic dimensions, which limits the applicability of classical continuum-type constitutive models. Cosserat

  12. Recursive definition of global cellular-automata mappings

    DEFF Research Database (Denmark)

    Feldberg, Rasmus; Knudsen, Carsten; Rasmussen, Steen

    1994-01-01

    A method for a recursive definition of global cellular-automata mappings is presented. The method is based on a graphical representation of global cellular-automata mappings. For a given cellular-automaton rule the recursive algorithm defines the change of the global cellular-automaton mapping...... as the number of lattice sites is incremented. A proof of lattice size invariance of global cellular-automata mappings is derived from an approximation to the exact recursive definition. The recursive definitions are applied to calculate the fractal dimension of the set of reachable states and of the set...

  13. Evaluation of Structural Cellular Glass

    Science.gov (United States)

    Adams, M. A.; Zwissler, J. G.

    1984-01-01

    Preliminary design information presented. First report discusses state of structural-cellular-glass programs as of June 1979. Second report gives further details of program to develop improved cellular glasses and to characterize properties of glasses and commercially available materials.

  14. Language and other artifacts: socio-cultural dynamics of niche construction.

    Science.gov (United States)

    Sinha, Chris

    2015-01-01

    Niche construction theory is a relatively new approach in evolutionary biology that seeks to integrate an ecological dimension into the Darwinian theory of evolution by natural selection. It is regarded by many evolutionary biologists as providing a significant revision of the Neo-Darwinian modern synthesis that unified Darwin's theory of natural and sexual selection with 20th century population genetics. Niche construction theory has been invoked as a processual mediator of social cognitive evolution and of the emergence and evolution of language. I argue that language itself can be considered as a biocultural niche and evolutionary artifact. I provide both a general analysis of the cognitive and semiotic status of artifacts, and a formal analysis of language as a social and semiotic institution, based upon a distinction between the fundamental semiotic relations of "counting as" and "standing for." I explore the consequences for theories of language and language learning of viewing language as a biocultural niche. I suggest that not only do niches mediate organism-organism interactions, but also that organisms mediate niche-niche interactions in ways that affect evolutionary processes, with the evolution of human infancy and childhood as a key example. I argue that language as a social and semiotic system is not only grounded in embodied engagements with the material and social-interactional world, but also grounds a sub-class of artifacts of particular significance in the cultural history of human cognition. Symbolic cognitive artifacts materially and semiotically mediate human cognition, and are not merely informational repositories, but co-agentively constitutive of culturally and historically emergent cognitive domains. I provide examples of the constitutive cognitive role of symbolic cognitive artifacts drawn from my research with my colleagues on cultural and linguistic conceptualizations of time, and their cultural variability. I conclude by reflecting on

  15. Selfishness, warfare and economics; or integration, cooperation and biology

    Directory of Open Access Journals (Sweden)

    Emiliano Jesus Salvucci

    2012-05-01

    Full Text Available The acceptance of Darwin's theory of evolution by natural selection is not complete and it has been pointed out its limitation to explain the complex processes that constitute the transformation of species. The darwinian paradigm had its origin in the free market theories and concepts of Malthus and Spencer. Nature was explained on the basis of market theories moving away from an accurate explanation of natural phenomena. It is common that new discoveries bring about contradictions that are intended to be overcome by adjusting results to the dominant reductionist paradigm using all sorts of gradations and combinations that are admitted for each case. Modern findings represent a challenge to the interpretation of the observations with the Darwinian view of competition and struggle for life as theoretical basis. New holistic interpretations are emerging related with the Net of Life, in which the interconnection of ecosystems constitutes a dynamic and self-regulating biosphere: Viruses are recognized as a macroorganism with a huge collection of genes, most unknown, that constitute the major planet's gene pool with a fundamental role in evolution. The hologenome theory considers an organism and all of its associated symbiotic microbes as a result of symbiopoiesis. Microbes, helmints, that normally are understood as parasites, are cohabitants and they have cohabited with their host and drives the evolution and existence of the partners. Each organism is a result of integration of complex systems. The eukaryotic organism is the result of combination of bacterial, virus and eukaryotic DNA and the interaction of its own genome with the genome of its microbiota resulting in an intertwined metabolism (a superorganism along evolution. These new interpretations are remarkable points to be considered in order to construct a solid theory adjusted to the facts and with less speculations and tortuous semantic traps.

  16. An evolutionary framework for cultural change: Selectionism versus communal exchange

    Science.gov (United States)

    Gabora, Liane

    2013-06-01

    Dawkins' replicator-based conception of evolution has led to widespread mis-application of selectionism across the social sciences because it does not address the paradox that necessitated the theory of natural selection in the first place: how do organisms accumulate change when traits acquired over their lifetime are obliterated? This is addressed by von Neumann's concept of a self-replicating automaton (SRA). A SRA consists of a self-assembly code that is used in two distinct ways: (1) actively deciphered during development to construct a self-similar replicant, and (2) passively copied to the replicant to ensure that it can reproduce. Information that is acquired over a lifetime is not transmitted to offspring, whereas information that is inherited during copying is transmitted. In cultural evolution there is no mechanism for discarding acquired change. Acquired change can accumulate orders of magnitude faster than, and quickly overwhelm, inherited change due to differential replication of variants in response to selection. This prohibits a selectionist but not an evolutionary framework for culture and the creative processes that fuel it. The importance non-Darwinian processes in biological evolution is increasingly recognized. Recent work on the origin of life suggests that early life evolved through a non-Darwinian process referred to as communal exchange that does not involve a self-assembly code, and that natural selection emerged from this more haphazard, ancestral evolutionary process. It is proposed that communal exchange provides an evolutionary framework for culture that enables specification of cognitive features necessary for a (real or artificial) societies to evolve culture. This is supported by a computational model of cultural evolution and a conceptual network based program for documenting material cultural history, and it is consistent with high levels of human cooperation.

  17. Language and other artifacts: socio-cultural dynamics of niche construction.

    Directory of Open Access Journals (Sweden)

    Chris eSinha

    2015-10-01

    Full Text Available Niche construction theory is a relatively new approach in evolutionary biology that seeks to integrate an ecological dimension into the Darwinian theory of evolution by natural selection. It is regarded by many evolutionary biologists as providing a significant revision of the Neo-Darwinian modern synthesis that unified Darwin’s theory of natural and sexual selection with 20th century population genetics. Niche construction theory has been invoked as a processual mediator of social cognitive evolution and of the emergence and evolution of language. I argue that language itself can be considered as a biocultural niche and evolutionary artifact. I provide both a general analysis of the cognitive and semiotic status of artifacts, and a formal analysis of language as a social and semiotic institution, based upon a distinction between the fundamental semiotic relations of counting as and standing for. I explore the consequences for theories of language and language learning of viewing language as a biocultural niche. I suggest that not only do niches mediate organism-organism interactions, but also that organisms mediate niche-niche interactions in ways that affect evolutionary processes, with the evolution of human infancy and childhood as a key example. I argue that language as a social and semiotic system is not only grounded in embodied engagements with the material and social-interactional world, but also grounds a sub-class of artifacts of particular significance in the cultural history of human cognition. Symbolic cognitive artifacts materially and semiotically mediate human cognition, and are not merely informational repositories, but co-agentively constitutive of culturally and historically emergent cognitive domains. I provide examples of the constitutive cognitive role of symbolic cognitive artifacts drawn from my research with my colleagues on cultural and linguistic conceptualizations of time, and their cultural variability. I conclude

  18. Epigenetics and Cellular Metabolism

    OpenAIRE

    Wenyi Xu; Fengzhong Wang; Zhongsheng Yu; Fengjiao Xin

    2016-01-01

    Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc.) is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the proce...

  19. Culture evolves

    OpenAIRE

    Whiten, Andrew; Hinde, Robert A.; Laland, Kevin N.; Stringer, Christopher B.

    2011-01-01

    Culture pervades human lives and has allowed our species to create niches all around the world and its oceans, in ways quite unlike any other primate. Indeed, our cultural nature appears so distinctive that it is often thought to separate humanity from the rest of nature and the Darwinian forces that shape it. A contrary view arises through the recent discoveries of a diverse range of disciplines, here brought together to illustrate the scope of a burgeoning field of cultural evolution and to...

  20. Sexual Selection of Human Cooperative Behaviour: An Experimental Study in Rural Senegal

    OpenAIRE

    Tognetti, Arnaud; Berticat, Claire; Raymond, Michel; Faurie, Charlotte

    2012-01-01

    Human cooperation in large groups and between non-kin individuals remains a Darwinian puzzle. Investigations into whether and how sexual selection is involved in the evolution of cooperation represent a new and important research direction. Here, 69 groups of four men or four women recruited from a rural population in Senegal played a sequential public-good game in the presence of out-group observers, either of the same sex or of the opposite sex. At the end of the game, participants could do...

  1. Modeling the mechanics of cancer: effect of changes in cellular and extra-cellular mechanical properties.

    Science.gov (United States)

    Katira, Parag; Bonnecaze, Roger T; Zaman, Muhammad H

    2013-01-01

    Malignant transformation, though primarily driven by genetic mutations in cells, is also accompanied by specific changes in cellular and extra-cellular mechanical properties such as stiffness and adhesivity. As the transformed cells grow into tumors, they interact with their surroundings via physical contacts and the application of forces. These forces can lead to changes in the mechanical regulation of cell fate based on the mechanical properties of the cells and their surrounding environment. A comprehensive understanding of cancer progression requires the study of how specific changes in mechanical properties influences collective cell behavior during tumor growth and metastasis. Here we review some key results from computational models describing the effect of changes in cellular and extra-cellular mechanical properties and identify mechanistic pathways for cancer progression that can be targeted for the prediction, treatment, and prevention of cancer.

  2. A Phylogenomic Census of Molecular Functions Identifies Modern Thermophilic Archaea as the Most Ancient Form of Cellular Life

    Directory of Open Access Journals (Sweden)

    Arshan Nasir

    2014-01-01

    Full Text Available The origins of diversified life remain mysterious despite considerable efforts devoted to untangling the roots of the universal tree of life. Here we reconstructed phylogenies that described the evolution of molecular functions and the evolution of species directly from a genomic census of gene ontology (GO definitions. We sampled 249 free-living genomes spanning organisms in the three superkingdoms of life, Archaea, Bacteria, and Eukarya, and used the abundance of GO terms as molecular characters to produce rooted phylogenetic trees. Results revealed an early thermophilic origin of Archaea that was followed by genome reduction events in microbial superkingdoms. Eukaryal genomes displayed extraordinary functional diversity and were enriched with hundreds of novel molecular activities not detected in the akaryotic microbial cells. Remarkably, the majority of these novel functions appeared quite late in evolution, synchronized with the diversification of the eukaryal superkingdom. The distribution of GO terms in superkingdoms confirms that Archaea appears to be the simplest and most ancient form of cellular life, while Eukarya is the most diverse and recent.

  3. A phylogenomic census of molecular functions identifies modern thermophilic archaea as the most ancient form of cellular life.

    Science.gov (United States)

    Nasir, Arshan; Kim, Kyung Mo; Caetano-Anollés, Gustavo

    2014-01-01

    The origins of diversified life remain mysterious despite considerable efforts devoted to untangling the roots of the universal tree of life. Here we reconstructed phylogenies that described the evolution of molecular functions and the evolution of species directly from a genomic census of gene ontology (GO) definitions. We sampled 249 free-living genomes spanning organisms in the three superkingdoms of life, Archaea, Bacteria, and Eukarya, and used the abundance of GO terms as molecular characters to produce rooted phylogenetic trees. Results revealed an early thermophilic origin of Archaea that was followed by genome reduction events in microbial superkingdoms. Eukaryal genomes displayed extraordinary functional diversity and were enriched with hundreds of novel molecular activities not detected in the akaryotic microbial cells. Remarkably, the majority of these novel functions appeared quite late in evolution, synchronized with the diversification of the eukaryal superkingdom. The distribution of GO terms in superkingdoms confirms that Archaea appears to be the simplest and most ancient form of cellular life, while Eukarya is the most diverse and recent.

  4. Integrating protein structures and precomputed genealogies in the Magnum database: Examples with cellular retinoid binding proteins

    Directory of Open Access Journals (Sweden)

    Bradley Michael E

    2006-02-01

    Full Text Available Abstract Background When accurate models for the divergent evolution of protein sequences are integrated with complementary biological information, such as folded protein structures, analyses of the combined data often lead to new hypotheses about molecular physiology. This represents an excellent example of how bioinformatics can be used to guide experimental research. However, progress in this direction has been slowed by the lack of a publicly available resource suitable for general use. Results The precomputed Magnum database offers a solution to this problem for ca. 1,800 full-length protein families with at least one crystal structure. The Magnum deliverables include 1 multiple sequence alignments, 2 mapping of alignment sites to crystal structure sites, 3 phylogenetic trees, 4 inferred ancestral sequences at internal tree nodes, and 5 amino acid replacements along tree branches. Comprehensive evaluations revealed that the automated procedures used to construct Magnum produced accurate models of how proteins divergently evolve, or genealogies, and correctly integrated these with the structural data. To demonstrate Magnum's capabilities, we asked for amino acid replacements requiring three nucleotide substitutions, located at internal protein structure sites, and occurring on short phylogenetic tree branches. In the cellular retinoid binding protein family a site that potentially modulates ligand binding affinity was discovered. Recruitment of cellular retinol binding protein to function as a lens crystallin in the diurnal gecko afforded another opportunity to showcase the predictive value of a browsable database containing branch replacement patterns integrated with protein structures. Conclusion We integrated two areas of protein science, evolution and structure, on a large scale and created a precomputed database, known as Magnum, which is the first freely available resource of its kind. Magnum provides evolutionary and structural

  5. Positive Darwinian selection in the piston that powers proton pumps in complex I of the mitochondria of Pacific salmon.

    Science.gov (United States)

    Garvin, Michael R; Bielawski, Joseph P; Gharrett, Anthony J

    2011-01-01

    The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm.

  6. Positive Darwinian Selection in the Piston That Powers Proton Pumps in Complex I of the Mitochondria of Pacific Salmon

    Science.gov (United States)

    Garvin, Michael R.; Bielawski, Joseph P.; Gharrett, Anthony J.

    2011-01-01

    The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm. PMID:21969854

  7. Cellular Stress Response to Engineered Nanoparticles: Effect of Size, Surface Coating, and Cellular Uptake

    Science.gov (United States)

    CELLULAR STRESS RESPONSE TO ENGINEERED NANOPARTICLES: EFFECT OF SIZE, SURFACE COATING, AND CELLULAR UPTAKE RY Prasad 1, JK McGee2, MG Killius1 D Ackerman2, CF Blackman2 DM DeMarini2 , SO Simmons2 1 Student Services Contractor, US EPA, RTP, NC 2 US EPA, RTP, NC The num...

  8. Making Heredity Matter: Samuel Butler's Idea of Unconscious Memory.

    Science.gov (United States)

    Turbil, Cristiano

    2018-03-01

    Butler's idea of evolution was developed over the publication of four books, several articles and essays between 1863 and 1890. These publications, although never achieving the success expected by Butler, proposed a psychological elaboration of evolution (robustly enforced by Lamarck's philosophy), called 'unconscious memory'. This was strongly in contrast with the materialistic approach suggested by Darwin's natural selection. Starting with a historical introduction, this paper aspires to ascertain the logic, meaning and significance of Butler's idea of 'unconscious memory' in the post-Darwinian physiological and psychological Pan-European discussion. Particular attention is devoted to demonstrating that Butler was not only a populariser of science but also an active protagonist in the late Victorian psychological debate.

  9. Lecture One: Rediscovering Darwin for theology – Rethinking human personhood

    Directory of Open Access Journals (Sweden)

    J. Wentzel van Huyssteen

    2017-11-01

    Full Text Available In a series of three articles, presented at the Goshen Annual Conference on Science and Religion in 2015, with the theme ‘Interdisciplinary Theology and the Archeology of Personhood’, J. Wentzel van Huyssteen considers the problem of human evolution – also referred to as ‘the archaeology of personhood’ – and its broader impact on theological anthropology. These Goshen Lectures explore the potentiality that the history of human evolution provides bridge theories to theological anthropology and thus to a positive and constructive way of appropriating Darwinian thought for a public, interdisciplinary Christian theology. Lecture One tracks a select number of contemporary proposals for the evolution of aspects of human personhood. These aspects were of significance for Darwin: the evolution of cognition; the evolution of imagination, music and language; the evolution of morality; and the evolution of the religious disposition. The article acknowledges the close ties to hominid ancestors and focuses on the emergence of human distinctiveness, consciousness and personhood, and the propensity for religious awareness and experience.

  10. Implications of a fossil stickleback assemblage for Darwinian gradualism.

    Science.gov (United States)

    Bell, M A

    2009-11-01

    Darwin postulated that a complete fossil record would contain numerous gradual transitions between ancestral and descendant species, but 150 years after publication of The Origin of Species, few such transitions have materialized. The fossil stickleback Gasterosteus doryssus and the deposit in which it occurs provide excellent conditions to detect such transitions. Abundant, well-preserved fossils occur in a stratigraphic setting with fine temporal resolution. The paleoecology of G. doryssus resembles the ecology of modern lakes that harbour the phenotypically similar three-spined stickleback Gasterosteus aculeatus. Gasterosteus aculeatus are primitively highly armoured, but G. doryssus comprised two contemporaneous biological species with relatively weak armour, including a near-shore, benthic feeder (benthic) and an offshore planktivore (limnetic). The benthic species expanded its range into the limnetic zone of the lake, where it apparently switched to planktivory and evolved reduced armour within c. 5000 years in response to directional selection. Although gradual evolution of mean phenotypes occurred, a single major gene caused much of evolutionary change of the pelvic skeleton. Thus, Darwin's expectation that transitions between species in the fossil record would be gradual was met at a fine time scale, but for pelvic structure, a well-studied trait, his expectation that gradual change would depend entirely on numerous, small, heritable differences among individuals was incorrect.

  11. Epigenetics and Cellular Metabolism

    Directory of Open Access Journals (Sweden)

    Wenyi Xu

    2016-01-01

    Full Text Available Living eukaryotic systems evolve delicate cellular mechanisms for responding to various environmental signals. Among them, epigenetic machinery (DNA methylation, histone modifications, microRNAs, etc. is the hub in transducing external stimuli into transcriptional response. Emerging evidence reveals the concept that epigenetic signatures are essential for the proper maintenance of cellular metabolism. On the other hand, the metabolite, a main environmental input, can also influence the processing of epigenetic memory. Here, we summarize the recent research progress in the epigenetic regulation of cellular metabolism and discuss how the dysfunction of epigenetic machineries influences the development of metabolic disorders such as diabetes and obesity; then, we focus on discussing the notion that manipulating metabolites, the fuel of cell metabolism, can function as a strategy for interfering epigenetic machinery and its related disease progression as well.

  12. Cellular-based preemption system

    Science.gov (United States)

    Bachelder, Aaron D. (Inventor)

    2011-01-01

    A cellular-based preemption system that uses existing cellular infrastructure to transmit preemption related data to allow safe passage of emergency vehicles through one or more intersections. A cellular unit in an emergency vehicle is used to generate position reports that are transmitted to the one or more intersections during an emergency response. Based on this position data, the one or more intersections calculate an estimated time of arrival (ETA) of the emergency vehicle, and transmit preemption commands to traffic signals at the intersections based on the calculated ETA. Additional techniques may be used for refining the position reports, ETA calculations, and the like. Such techniques include, without limitation, statistical preemption, map-matching, dead-reckoning, augmented navigation, and/or preemption optimization techniques, all of which are described in further detail in the above-referenced patent applications.

  13. Positive Darwinian selection in the piston that powers proton pumps in complex I of the mitochondria of Pacific salmon.

    Directory of Open Access Journals (Sweden)

    Michael R Garvin

    Full Text Available The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm.

  14. A NANOFLARE-BASED CELLULAR AUTOMATON MODEL AND THE OBSERVED PROPERTIES OF THE CORONAL PLASMA

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, Marcelo López [Instituto de Astronomía y Física del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Klimchuk, James A., E-mail: lopezf@iafe.uba.ar [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States)

    2016-09-10

    We use the cellular automaton model described in López Fuentes and Klimchuk to study the evolution of coronal loop plasmas. The model, based on the idea of a critical misalignment angle in tangled magnetic fields, produces nanoflares of varying frequency with respect to the plasma cooling time. We compare the results of the model with active region (AR) observations obtained with the Hinode /XRT and SDO /AIA instruments. The comparison is based on the statistical properties of synthetic and observed loop light curves. Our results show that the model reproduces the main observational characteristics of the evolution of the plasma in AR coronal loops. The typical intensity fluctuations have amplitudes of 10%–15% both for the model and the observations. The sign of the skewness of the intensity distributions indicates the presence of cooling plasma in the loops. We also study the emission measure (EM) distribution predicted by the model and obtain slopes in log(EM) versus log(T) between 2.7 and 4.3, in agreement with published observational values.

  15. A Nanoflare-Based Cellular Automaton Model and the Observed Properties of the Coronal Plasma

    Science.gov (United States)

    Lopez-Fuentes, Marcelo; Klimchuk, James Andrew

    2016-01-01

    We use the cellular automaton model described in Lopez Fuentes and Klimchuk to study the evolution of coronal loop plasmas. The model, based on the idea of a critical misalignment angle in tangled magnetic fields, produces nanoflares of varying frequency with respect to the plasma cooling time. We compare the results of the model with active region (AR) observations obtained with the Hinode/XRT and SDOAIA instruments. The comparison is based on the statistical properties of synthetic and observed loop light curves. Our results show that the model reproduces the main observational characteristics of the evolution of the plasma in AR coronal loops. The typical intensity fluctuations have amplitudes of 10 percent - 15 percent both for the model and the observations. The sign of the skewness of the intensity distributions indicates the presence of cooling plasma in the loops. We also study the emission measure (EM) distribution predicted by the model and obtain slopes in log(EM) versus log(T) between 2.7 and 4.3, in agreement with published observational values.

  16. Cellular properties of slug flow in vertical co-current gas-liquid flow: slug-churn transition

    International Nuclear Information System (INIS)

    Lusseyran, Francois

    1990-01-01

    This research thesis reports the study and description of the structure of a slug flow regime in a co-current vertical cylindrical duct, and the characterization and prediction of its transition towards a slug-churn (de-structured) regime. Flow physical mechanisms highlighted by the measurement of two important dynamics variables (wall friction and thickness of liquid films) are related to hypotheses of cellular models. The author first proposes an overview of slug flow regimes: theoretical steady and one-dimensional analysis, mass assessment equations of cellular models, application to the assessment of the flow rate and of the thickness of the film surrounding the gas slug. In the second part, the author addresses the slug flow regime transition towards the slug-churn regime: assessment of the evolution of flow dynamic properties, use of average wall friction analysis to obtain a relevant transition criterion. The third part presents experimental conditions, and measurement methods: conductometry for thickness measurement, polarography for wall friction measurement, and gas phase detection by using an optic barrier or optic fibres [fr

  17. Cellular and Molecular Biological Approaches to Interpreting Ancient Biomarkers

    Science.gov (United States)

    Newman, Dianne K.; Neubauer, Cajetan; Ricci, Jessica N.; Wu, Chia-Hung; Pearson, Ann

    2016-06-01

    Our ability to read the molecular fossil record has advanced significantly in the past decade. Improvements in biomarker sampling and quantification methods, expansion of molecular sequence databases, and the application of genetic and cellular biological tools to problems in biomarker research have enabled much of this progress. By way of example, we review how attempts to understand the biological function of 2-methylhopanoids in modern bacteria have changed our interpretation of what their molecular fossils tell us about the early history of life. They were once thought to be biomarkers of cyanobacteria and hence the evolution of oxygenic photosynthesis, but we now believe that 2-methylhopanoid biosynthetic capacity originated in the Alphaproteobacteria, that 2-methylhopanoids are regulated in response to stress, and that hopanoid 2-methylation enhances membrane rigidity. We present a new interpretation of 2-methylhopanes that bridges the gap between studies of the functions of 2-methylhopanoids and their patterns of occurrence in the rock record.

  18. Lamarck needs Darwin: the search for purpose in the study of evolution and of history

    Directory of Open Access Journals (Sweden)

    Moreno, Juan

    2009-12-01

    Full Text Available Lamarck´s theory of the inheritance of acquired characteristics and immediate responses to environmental challenges has offered a promise of protagonism of human beings and their fellow trvellers, the other organisms, in the evolutionary process. Darwin’s theory about evolution by natural selection does not offer this consolation and does not presuppose anything else other than gradual cahnges in the composition of natural populations. The study of ecology, ethology, neurobiology, animal culture, psichology and human history reveals that the lamarckian interpretations of change and character transmission processes always assume what they intend to explain, that is previous processes of darwinian evolution that guarantee the adaptive nature of the observed responses. The permanent search of direction and intentionality in evolutionary processes by many scientists suggests the limited acceptance of materilaistic explanations as those offered by Darwin’s theory.

    a teoría de Lamarck sobre herencia de caracteres adquiridos y sobre respuestas inmediatas a retos ambientales ha ofrecido una promesa de intencionalidad y protagonismo en el proceso evolutivo al ser humano y a los restantes organismos. La teoría de Darwin sobre evolución por selección natural no ofrece este consuelo y no presupone nada más que procesos de recambio gradual en poblaciones naturales. El estudio de la ecología, la etología, la neurobiología, la cultura animal, la psicología y la historia humana revela que las interpretaciones lamarckianas de los cambios y procesos de transmisión de caracteres presuponen siempre lo que pretenden explicar, es decir procesos previos de evolución darwiniana que garantizan la naturaleza adaptativa de las respuestas observadas. La búsqueda continua de dirección y de intención en los procesos evolutivos por muchos científicos sugiere la escasa aceptación de explicaciones materialistas como las que ofrece la teoría de

  19. Probabilistic cellular automata.

    Science.gov (United States)

    Agapie, Alexandru; Andreica, Anca; Giuclea, Marius

    2014-09-01

    Cellular automata are binary lattices used for modeling complex dynamical systems. The automaton evolves iteratively from one configuration to another, using some local transition rule based on the number of ones in the neighborhood of each cell. With respect to the number of cells allowed to change per iteration, we speak of either synchronous or asynchronous automata. If randomness is involved to some degree in the transition rule, we speak of probabilistic automata, otherwise they are called deterministic. With either type of cellular automaton we are dealing with, the main theoretical challenge stays the same: starting from an arbitrary initial configuration, predict (with highest accuracy) the end configuration. If the automaton is deterministic, the outcome simplifies to one of two configurations, all zeros or all ones. If the automaton is probabilistic, the whole process is modeled by a finite homogeneous Markov chain, and the outcome is the corresponding stationary distribution. Based on our previous results for the asynchronous case-connecting the probability of a configuration in the stationary distribution to its number of zero-one borders-the article offers both numerical and theoretical insight into the long-term behavior of synchronous cellular automata.

  20. 47 CFR 32.5003 - Cellular mobile revenue.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Cellular mobile revenue. 32.5003 Section 32... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions For Revenue Accounts § 32.5003 Cellular mobile revenue. This account shall include message revenue derived from cellular mobile...

  1. On the Evolution of the Mammalian Brain.

    Science.gov (United States)

    Torday, John S; Miller, William B

    2016-01-01

    Hobson and Friston have hypothesized that the brain must actively dissipate heat in order to process information (Hobson et al., 2014). This physiologic trait is functionally homologous with the first instantation of life formed by lipids suspended in water forming micelles- allowing the reduction in entropy (heat dissipation). This circumvents the Second Law of Thermodynamics permitting the transfer of information between living entities, enabling them to perpetually glean information from the environment, that is felt by many to correspond to evolution per se. The next evolutionary milestone was the advent of cholesterol, embedded in the cell membranes of primordial eukaryotes, facilitating metabolism, oxygenation and locomotion, the triadic basis for vertebrate evolution. Lipids were key to homeostatic regulation of calcium, forming calcium channels. Cell membrane cholesterol also fostered metazoan evolution by forming lipid rafts for receptor-mediated cell-cell signaling, the origin of the endocrine system. The eukaryotic cell membrane exapted to all complex physiologic traits, including the lung and brain, which are molecularly homologous through the function of neuregulin, mediating both lung development and myelinization of neurons. That cooption later exapted as endothermy during the water-land transition (Torday, 2015a), perhaps being the functional homolog for brain heat dissipation and conscious/mindful information processing. The skin and brain similarly share molecular homologies through the "skin-brain" hypothesis, giving insight to the cellular-molecular "arc" of consciousness from its unicellular origins to integrated physiology. This perspective on the evolution of the central nervous system clarifies self-organization, reconciling thermodynamic and informational definitions of the underlying biophysical mechanisms, thereby elucidating relations between the predictive capabilities of the brain and self-organizational processes.

  2. Assessment of General Public Exposure to LTE signals compared to other Cellular Networks Present in Thessaloniki, Greece.

    Science.gov (United States)

    Gkonis, Fotios; Boursianis, Achilles; Samaras, Theodoros

    2017-07-01

    To assess general public exposure to electromagnetic fields from Long Term Evolution (LTE) base stations, measurements at 10 sites in Thessaloniki, Greece were performed. Results are compared with other mobile cellular networks currently in use. All exposure values satisfy the guidelines for general public exposure of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), as well as the reference levels by the Greek legislation at all sites. LTE electric field measurements were recorded up to 0.645 V/m. By applying the ICNIRP guidelines, the exposure ratio for all LTE signals is between 2.9 × 10-5 and 2.8 × 10-2. From the measurements results it is concluded that the average and maximum power density contribution of LTE downlink signals to the overall cellular networks signals are 7.8% and 36.7%, respectively. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. 47 CFR 22.905 - Channels for cellular service.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Channels for cellular service. 22.905 Section... MOBILE SERVICES Cellular Radiotelephone Service § 22.905 Channels for cellular service. The following frequency bands are allocated for assignment to service providers in the Cellular Radiotelephone Service. (a...

  4. 47 CFR 22.901 - Cellular service requirements and limitations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Cellular service requirements and limitations... SERVICES PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.901 Cellular service requirements and limitations. The licensee of each cellular system is responsible for ensuring that its cellular system...

  5. Evolution of circadian organization in vertebrates

    Directory of Open Access Journals (Sweden)

    M. Menaker

    1997-03-01

    Full Text Available Circadian organization means the way in which the entire circadian system above the cellular level is put together physically and the principles and rules that determine the interactions among its component parts which produce overt rhythms of physiology and behavior. Understanding this organization and its evolution is of practical importance as well as of basic interest. The first major problem that we face is the difficulty of making sense of the apparently great diversity that we observe in circadian organization of diverse vertebrates. Some of this diversity falls neatly into place along phylogenetic lines leading to firm generalizations: i in all vertebrates there is a "circadian axis" consisting of the retinas, the pineal gland and the suprachiasmatic nucleus (SCN, ii in many non-mammalian vertebrates of all classes (but not in any mammals the pineal gland is both a photoreceptor and a circadian oscillator, and iii in all non-mammalian vertebrates (but not in any mammals there are extraretinal (and extrapineal circadian photoreceptors. An interesting explanation of some of these facts, especially the differences between mammals and other vertebrates, can be constructed on the assumption that early in their evolution mammals passed through a "nocturnal bottleneck". On the other hand, a good deal of the diversity among the circadian systems of vertebrates does not fall neatly into place along phylogenetic lines. In the present review we will consider how we might better understand such "phylogenetically incoherent" diversity and what sorts of new information may help to further our understanding of the evolution of circadian organization in vertebrates

  6. Exponential growth for self-reproduction in a catalytic reaction network: relevance of a minority molecular species and crowdedness

    Science.gov (United States)

    Kamimura, Atsushi; Kaneko, Kunihiko

    2018-03-01

    Explanation of exponential growth in self-reproduction is an important step toward elucidation of the origins of life because optimization of the growth potential across rounds of selection is necessary for Darwinian evolution. To produce another copy with approximately the same composition, the exponential growth rates for all components have to be equal. How such balanced growth is achieved, however, is not a trivial question, because this kind of growth requires orchestrated replication of the components in stochastic and nonlinear catalytic reactions. By considering a mutually catalyzing reaction in two- and three-dimensional lattices, as represented by a cellular automaton model, we show that self-reproduction with exponential growth is possible only when the replication and degradation of one molecular species is much slower than those of the others, i.e., when there is a minority molecule. Here, the synergetic effect of molecular discreteness and crowding is necessary to produce the exponential growth. Otherwise, the growth curves show superexponential growth because of nonlinearity of the catalytic reactions or subexponential growth due to replication inhibition by overcrowding of molecules. Our study emphasizes that the minority molecular species in a catalytic reaction network is necessary for exponential growth at the primitive stage of life.

  7. Growth kinetics of cellular precipitation in a Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Contreras-Piedras, Edgar [Instituto Politecnico Nacional-ESIQIE-DIMM-ESFM, Apartado Postal 118-430, Admon. GAM, Mexico, D.F. 07051 (Mexico); Esquivel-Gonzalez, Ramon [Universidad del Valle de Mexico, Depto. Ingenierias, Paseo de las Aves 1, Col. San Mateo Nopala, Lomas Verdes, Naucalpan de Juarez, Edo. Mex. 53220 (Mexico); Lopez-Hirata, Victor M.; Saucedo-Munoz, M.L.; Paniagua-Mercado, Ana M. [Instituto Politecnico Nacional-ESIQIE-DIMM-ESFM, Apartado Postal 118-430, Admon. GAM, Mexico, D.F. 07051 (Mexico); Dorantes-Rosales, Hector J., E-mail: hectordorantes@yahoo.com [Instituto Politecnico Nacional-ESIQIE-DIMM-ESFM, Apartado Postal 118-430, Admon. GAM, Mexico, D.F. 07051 (Mexico)

    2010-11-15

    Research highlights: {yields} The growth kinetics of lamellar spacing follows the behavior predicted by Turnbull theory. {yields} The growth kinetics of cellular precipitation is a process controlled by grain boundary diffusion. {yields} The presence of two types of morphology for cellular precipitation depends on the aging temperature. {yields} The highest hardness peak is associated to a fine continuous precipitation at the lowest temperature. {yields} The lowest hardness is attributed to the fast coarsening process of both precipitations. - Abstract: Microstructural evolution and growth kinetics were studied in an isothermally aged Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy by means of X-ray diffraction, scanning electron microscopy, Vickers hardness measurements and transmission electron microscopy. Specimens were solution-treated and then aged at 373, 473 and 573 K for different time period. The characterization results indicated the presence of both continuous and discontinuous precipitations of the Mg{sub 17}Al{sub 12}-{gamma} phase in a Mg-rich matrix. The discontinuous or cellular precipitation was present with a lamellar structure, and the growth kinetics was evaluated using the Johnson-Mehl-Avrami-Kolmogorov equation analysis, which gives a time exponent close to 1. This value confirms that cellular precipitation takes place on the saturation sites corresponding to grain boundaries. In addition, the activation energy for cellular precipitation was determined to be about 64.6 kJ mol{sup -1}. This also indicates a grain boundary diffusion process. The variation of cellular spacing with temperature follows the behavior expected by Turnbull theory. The highest hardness peak corresponded to the lowest aging temperature and it is associated with a fine continuous precipitation; while the lowest hardness peak was detected at the highest aging temperature and it is attributed to the rapid coarsening process of both precipitations.

  8. Growth kinetics of cellular precipitation in a Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy

    International Nuclear Information System (INIS)

    Contreras-Piedras, Edgar; Esquivel-Gonzalez, Ramon; Lopez-Hirata, Victor M.; Saucedo-Munoz, M.L.; Paniagua-Mercado, Ana M.; Dorantes-Rosales, Hector J.

    2010-01-01

    Research highlights: → The growth kinetics of lamellar spacing follows the behavior predicted by Turnbull theory. → The growth kinetics of cellular precipitation is a process controlled by grain boundary diffusion. → The presence of two types of morphology for cellular precipitation depends on the aging temperature. → The highest hardness peak is associated to a fine continuous precipitation at the lowest temperature. → The lowest hardness is attributed to the fast coarsening process of both precipitations. - Abstract: Microstructural evolution and growth kinetics were studied in an isothermally aged Mg-8.5Al-0.5Zn-0.2Mn (wt.%) alloy by means of X-ray diffraction, scanning electron microscopy, Vickers hardness measurements and transmission electron microscopy. Specimens were solution-treated and then aged at 373, 473 and 573 K for different time period. The characterization results indicated the presence of both continuous and discontinuous precipitations of the Mg 17 Al 12 -γ phase in a Mg-rich matrix. The discontinuous or cellular precipitation was present with a lamellar structure, and the growth kinetics was evaluated using the Johnson-Mehl-Avrami-Kolmogorov equation analysis, which gives a time exponent close to 1. This value confirms that cellular precipitation takes place on the saturation sites corresponding to grain boundaries. In addition, the activation energy for cellular precipitation was determined to be about 64.6 kJ mol -1 . This also indicates a grain boundary diffusion process. The variation of cellular spacing with temperature follows the behavior expected by Turnbull theory. The highest hardness peak corresponded to the lowest aging temperature and it is associated with a fine continuous precipitation; while the lowest hardness peak was detected at the highest aging temperature and it is attributed to the rapid coarsening process of both precipitations.

  9. Cellular phone use while driving at night.

    Science.gov (United States)

    Vivoda, Jonathon M; Eby, David W; St Louis, Renée M; Kostyniuk, Lidia P

    2008-03-01

    Use of a cellular phone has been shown to negatively affect one's attention to the driving task, leading to an increase in crash risk. At any given daylight hour, about 6% of US drivers are actively talking on a hand-held cell phone. However, previous surveys have focused only on cell phone use during the day. Driving at night has been shown to be a riskier activity than driving during the day. The purpose of the current study was to assess the rate of hand-held cellular phone use while driving at night, using specialized night vision equipment. In 2006, two statewide direct observation survey waves of nighttime cellular phone use were conducted in Indiana utilizing specialized night vision equipment. Combined results of driver hand-held cellular phone use from both waves are presented in this manuscript. The rates of nighttime cell phone use were similar to results found in previous daytime studies. The overall rate of nighttime hand-held cellular phone use was 5.8 +/- 0.6%. Cellular phone use was highest for females and for younger drivers. In fact, the highest rate observed during the study (of 11.9%) was for 16-to 29-year-old females. The high level of cellular phone use found within the young age group, coupled with the increased crash risk associated with cellular phone use, nighttime driving, and for young drivers in general, suggests that this issue may become an important transportation-related concern.

  10. Genome evolution during progression to breast cancer

    KAUST Repository

    Newburger, D. E.; Kashef-Haghighi, D.; Weng, Z.; Salari, R.; Sweeney, R. T.; Brunner, A. L.; Zhu, S. X.; Guo, X.; Varma, S.; Troxell, M. L.; West, R. B.; Batzoglou, S.; Sidow, A.

    2013-01-01

    Cancer evolution involves cycles of genomic damage, epigenetic deregulation, and increased cellular proliferation that eventually culminate in the carcinoma phenotype. Early neoplasias, which are often found concurrently with carcinomas and are histologically distinguishable from normal breast tissue, are less advanced in phenotype than carcinomas and are thought to represent precursor stages. To elucidate their role in cancer evolution we performed comparative whole-genome sequencing of early neoplasias, matched normal tissue, and carcinomas from six patients, for a total of 31 samples. By using somatic mutations as lineage markers we built trees that relate the tissue samples within each patient. On the basis of these lineage trees we inferred the order, timing, and rates of genomic events. In four out of six cases, an early neoplasia and the carcinoma share a mutated common ancestor with recurring aneuploidies, and in all six cases evolution accelerated in the carcinoma lineage. Transition spectra of somatic mutations are stable and consistent across cases, suggesting that accumulation of somatic mutations is a result of increased ancestral cell division rather than specific mutational mechanisms. In contrast to highly advanced tumors that are the focus of much of the current cancer genome sequencing, neither the early neoplasia genomes nor the carcinomas are enriched with potentially functional somatic point mutations. Aneuploidies that occur in common ancestors of neoplastic and tumor cells are the earliest events that affect a large number of genes and may predispose breast tissue to eventual development of invasive carcinoma.

  11. Genome evolution during progression to breast cancer

    KAUST Repository

    Newburger, D. E.

    2013-04-08

    Cancer evolution involves cycles of genomic damage, epigenetic deregulation, and increased cellular proliferation that eventually culminate in the carcinoma phenotype. Early neoplasias, which are often found concurrently with carcinomas and are histologically distinguishable from normal breast tissue, are less advanced in phenotype than carcinomas and are thought to represent precursor stages. To elucidate their role in cancer evolution we performed comparative whole-genome sequencing of early neoplasias, matched normal tissue, and carcinomas from six patients, for a total of 31 samples. By using somatic mutations as lineage markers we built trees that relate the tissue samples within each patient. On the basis of these lineage trees we inferred the order, timing, and rates of genomic events. In four out of six cases, an early neoplasia and the carcinoma share a mutated common ancestor with recurring aneuploidies, and in all six cases evolution accelerated in the carcinoma lineage. Transition spectra of somatic mutations are stable and consistent across cases, suggesting that accumulation of somatic mutations is a result of increased ancestral cell division rather than specific mutational mechanisms. In contrast to highly advanced tumors that are the focus of much of the current cancer genome sequencing, neither the early neoplasia genomes nor the carcinomas are enriched with potentially functional somatic point mutations. Aneuploidies that occur in common ancestors of neoplastic and tumor cells are the earliest events that affect a large number of genes and may predispose breast tissue to eventual development of invasive carcinoma.

  12. Morphological evolution and internal strain mapping of pomelo peel using X-ray computed tomography and digital volume correlation

    KAUST Repository

    Wang, B.

    2017-10-15

    Cellular microstructures within natural materials enlighten and promote the development of novel materials and structures in the industrial and engineering fields. Characterization of the microstructures and mechanical properties of these natural materials can help to understand the morphology-related mechanical properties and guide the structural optimization in industrial design. Among these natural cellular materials, pomelo peels, having a foam-like hierarchical microstructure, represent an ideal model for developing materials with high energy absorption efficiency. In this work, by combining X-ray tomographic imaging technique and digital volume correlation (DVC), in-situ stepwise uniaxial compression tests were performed to quantify the internal morphological evolution and kinematic responses of pomelo peel samples during compression. Via these experiments, the varying microstructure features and thus diverse resistance to compression from endocarp to exocarp are examined, and the evolution of both bundles bending and large strain domain from endocarp to mesocarp are explored. Based on the experimental results, the microstructure-related mechanical properties of pomelo peels in response to compressive loading that demonstrates nearly linear morphology-mechanics relationship were revealed.

  13. An organismic critique of molecular darwinism.

    Science.gov (United States)

    Wicken, J S

    1985-12-21

    The molecular darwinian approach to the emergence of life treats the competition between RNA sequences for nucleotide resources as the primordial selective process in prebiotic evolution, which prescribes possible pathways for the subsequent elaboration of organizational relationships. Since success in this competition is determined by the "phenotypic" properties of RNA strands in the absence of organizational context, the genesis of biotic organization is dependent upon the establishment of co-operative, hypercyclic interactions between competing RNA sequences. The thesis of this paper is that hypercycle theory is based on unwarranted assumptions about the conditions of prebiotic evolution, and that the implications of these assumptions run counter to both empirical evidence and to the rational by which natural selection operates in evolution generally. An organismic alternative to hypercycle theory is suggested, based on the catalytic microsphere and the thermodynamics of selection.

  14. Outer-totalistic cellular automata on graphs

    International Nuclear Information System (INIS)

    Marr, Carsten; Huett, Marc-Thorsten

    2009-01-01

    We present an intuitive formalism for implementing cellular automata on arbitrary topologies. By that means, we identify a symmetry operation in the class of elementary cellular automata. Moreover, we determine the subset of topologically sensitive elementary cellular automata and find that the overall number of complex patterns decreases under increasing neighborhood size in regular graphs. As exemplary applications, we apply the formalism to complex networks and compare the potential of scale-free graphs and metabolic networks to generate complex dynamics

  15. Radiation, nitric oxide and cellular death

    International Nuclear Information System (INIS)

    Dubner, D.; Perez, M.R. Del; Michelin, S.C.; Gisone, P.A.

    1997-01-01

    The mechanisms of radiation induced cellular death constitute an objective of research ever since the first biological effects of radiation were first observed. The explosion of information produced in the last 20 years calls for a careful analysis due to the apparent contradictory data related to the cellular system studied and the range of doses used. This review focuses on the role of the active oxygen species, in particular the nitric oxides, in its relevance as potential mediator of radiation induced cellular death

  16. Predictability in cellular automata.

    Science.gov (United States)

    Agapie, Alexandru; Andreica, Anca; Chira, Camelia; Giuclea, Marius

    2014-01-01

    Modelled as finite homogeneous Markov chains, probabilistic cellular automata with local transition probabilities in (0, 1) always posses a stationary distribution. This result alone is not very helpful when it comes to predicting the final configuration; one needs also a formula connecting the probabilities in the stationary distribution to some intrinsic feature of the lattice configuration. Previous results on the asynchronous cellular automata have showed that such feature really exists. It is the number of zero-one borders within the automaton's binary configuration. An exponential formula in the number of zero-one borders has been proved for the 1-D, 2-D and 3-D asynchronous automata with neighborhood three, five and seven, respectively. We perform computer experiments on a synchronous cellular automaton to check whether the empirical distribution obeys also that theoretical formula. The numerical results indicate a perfect fit for neighbourhood three and five, which opens the way for a rigorous proof of the formula in this new, synchronous case.

  17. Invariant strings and pattern-recognizing properties of one-dimensional cellular automata

    International Nuclear Information System (INIS)

    Jen, E.

    1986-01-01

    A cellular automaton is a discrete dynamical system whose evolution is governed by a deterministic rule involving local interactions. It is shown that given an arbitrary string of values and an arbitry neighborhood size (representing the range of interaction), a simple procedure can be used to find the fules of that neighborhood size under which the string is unvarian. The set of nearestneighbor rules for which invariant strings exist is completely specified, as is the set of strings invariant under each such rule. For any automaton rule, an associated ''filtering'' rule is defined for which the only attractors are spatial sequences consisting of concatenations of invariant strings. A result is provided defining the rule of minimum neighborhood size for which an arbitrrily chosen string is the unique invariant string. The applications of filtering rules to pttern recognition problems are discussed

  18. Imaging in cellular and tissue engineering

    CERN Document Server

    Yu, Hanry

    2013-01-01

    Details on specific imaging modalities for different cellular and tissue engineering applications are scattered throughout articles and chapters in the literature. Gathering this information into a single reference, Imaging in Cellular and Tissue Engineering presents both the fundamentals and state of the art in imaging methods, approaches, and applications in regenerative medicine. The book underscores the broadening scope of imaging applications in cellular and tissue engineering. It covers a wide range of optical and biological applications, including the repair or replacement of whole tiss

  19. Mathematical Modeling of Tuberculosis Bacillary Counts and Cellular Populations in the Organs of Infected Mice

    Science.gov (United States)

    Bru, Antonio; Cardona, Pere-Joan

    2010-01-01

    Background Mycobacterium tuberculosis is a particularly aggressive microorganism and the host's defense is based on the induction of cellular immunity, in which the creation of a granulomatous structure has an important role. Methodology We present here a new 2D cellular automata model based on the concept of a multifunctional process that includes key factors such as the chemokine attraction of the cells; the role of innate immunity triggered by natural killers; the presence of neutrophils; apoptosis and necrosis of infected macrophages; the removal of dead cells by macrophages, which induces the production of foamy macrophages (FMs); the life cycle of the bacilli as a determinant for the evolution of infected macrophages; and the immune response. Results The results obtained after the inclusion of two degrees of tolerance to the inflammatory response triggered by the infection shows that the model can cover a wide spectrum, ranging from highly-tolerant (i.e. mice) to poorly-tolerant hosts (i.e. mini-pigs or humans). Conclusions This model suggest that stopping bacillary growth at the onset of the infection might be difficult and the important role played by FMs in bacillary drainage in poorly-tolerant hosts together with apoptosis and innate lymphocytes. It also shows the poor ability of the cellular immunity to control the infection, provides a clear protective character to the granuloma, due its ability to attract a sufficient number of cells, and explains why an already infected host can be constantly reinfected. PMID:20886087

  20. Dynamical patterning modules: physico-genetic determinants of morphological development and evolution

    International Nuclear Information System (INIS)

    Newman, Stuart A; Bhat, Ramray

    2008-01-01

    The shapes and forms of multicellular organisms arise by the generation of new cell states and types and changes in the numbers and rearrangements of the various kinds of cells. While morphogenesis and pattern formation in all animal species are widely recognized to be mediated by the gene products of an evolutionarily conserved 'developmental-genetic toolkit', the link between these molecular players and the physics underlying these processes has been generally ignored. This paper introduces the concept of 'dynamical patterning modules' (DPMs), units consisting of one or more products of the 'toolkit' genes that mobilize physical processes characteristic of chemically and mechanically excitable meso- to macroscopic systems such as cell aggregates: cohesion, viscoelasticity, diffusion, spatiotemporal heterogeneity based on lateral inhibition and multistable and oscillatory dynamics. We suggest that ancient toolkit gene products, most predating the emergence of multicellularity, assumed novel morphogenetic functions due to change in the scale and context inherent to multicellularity. We show that DPMs, acting individually and in concert with each other, constitute a 'pattern language' capable of generating all metazoan body plans and organ forms. The physical dimension of developmental causation implies that multicellular forms during the explosive radiation of animal body plans in the middle Cambrian, approximately 530 million years ago, could have explored an extensive morphospace without concomitant genotypic change or selection for adaptation. The morphologically plastic body plans and organ forms generated by DPMs, and their ontogenetic trajectories, would subsequently have been stabilized and consolidated by natural selection and genetic drift. This perspective also solves the apparent 'molecular homology-analogy paradox', whereby widely divergent modern animal types utilize the same molecular toolkit during development by proposing, in contrast to the Neo-Darwinian

  1. Characterizing heterogeneous cellular responses to perturbations.

    Science.gov (United States)

    Slack, Michael D; Martinez, Elisabeth D; Wu, Lani F; Altschuler, Steven J

    2008-12-09

    Cellular populations have been widely observed to respond heterogeneously to perturbation. However, interpreting the observed heterogeneity is an extremely challenging problem because of the complexity of possible cellular phenotypes, the large dimension of potential perturbations, and the lack of methods for separating meaningful biological information from noise. Here, we develop an image-based approach to characterize cellular phenotypes based on patterns of signaling marker colocalization. Heterogeneous cellular populations are characterized as mixtures of phenotypically distinct subpopulations, and responses to perturbations are summarized succinctly as probabilistic redistributions of these mixtures. We apply our method to characterize the heterogeneous responses of cancer cells to a panel of drugs. We find that cells treated with drugs of (dis-)similar mechanism exhibit (dis-)similar patterns of heterogeneity. Despite the observed phenotypic diversity of cells observed within our data, low-complexity models of heterogeneity were sufficient to distinguish most classes of drug mechanism. Our approach offers a computational framework for assessing the complexity of cellular heterogeneity, investigating the degree to which perturbations induce redistributions of a limited, but nontrivial, repertoire of underlying states and revealing functional significance contained within distinct patterns of heterogeneous responses.

  2. Movies of cellular and sub-cellular motion by digital holographic microscopy

    Directory of Open Access Journals (Sweden)

    Yu Lingfeng

    2006-03-01

    Full Text Available Abstract Background Many biological specimens, such as living cells and their intracellular components, often exhibit very little amplitude contrast, making it difficult for conventional bright field microscopes to distinguish them from their surroundings. To overcome this problem phase contrast techniques such as Zernike, Normarsky and dark-field microscopies have been developed to improve specimen visibility without chemically or physically altering them by the process of staining. These techniques have proven to be invaluable tools for studying living cells and furthering scientific understanding of fundamental cellular processes such as mitosis. However a drawback of these techniques is that direct quantitative phase imaging is not possible. Quantitative phase imaging is important because it enables determination of either the refractive index or optical thickness variations from the measured optical path length with sub-wavelength accuracy. Digital holography is an emergent phase contrast technique that offers an excellent approach in obtaining both qualitative and quantitative phase information from the hologram. A CCD camera is used to record a hologram onto a computer and numerical methods are subsequently applied to reconstruct the hologram to enable direct access to both phase and amplitude information. Another attractive feature of digital holography is the ability to focus on multiple focal planes from a single hologram, emulating the focusing control of a conventional microscope. Methods A modified Mach-Zender off-axis setup in transmission is used to record and reconstruct a number of holographic amplitude and phase images of cellular and sub-cellular features. Results Both cellular and sub-cellular features are imaged with sub-micron, diffraction-limited resolution. Movies of holographic amplitude and phase images of living microbes and cells are created from a series of holograms and reconstructed with numerically adjustable

  3. Probing Cellular Dynamics with Mesoscopic Simulations

    DEFF Research Database (Denmark)

    Shillcock, Julian C.

    2010-01-01

    Cellular processes span a huge range of length and time scales from the molecular to the near-macroscopic. Understanding how effects on one scale influence, and are themselves influenced by, those on lower and higher scales is a critical issue for the construction of models in Systems Biology....... Advances in computing hardware and software now allow explicit simulation of some aspects of cellular dynamics close to the molecular scale. Vesicle fusion is one example of such a process. Experiments, however, typically probe cellular behavior from the molecular scale up to microns. Standard particle...... soon be coupled to Mass Action models allowing the parameters in such models to be continuously tuned according to the finer resolution simulation. This will help realize the goal of a computational cellular simulation that is able to capture the dynamics of membrane-associated processes...

  4. On the evolution of the mammalian brain

    Directory of Open Access Journals (Sweden)

    John Steven Torday

    2016-04-01

    Full Text Available Hobson and Friston have hypothesized that the brain must actively dissipate heat in order to process information (Virtual reality and consciousness inference in dreaming. Front Psychol. 2014 Oct 9;5:1133.. This physiologic trait is functionally homologous with the first instantation of life formed by lipids suspended in water forming micelles- allowing the reduction in entropy (heat dissipation, circumventing the Second Law of Thermodynamics permitting the transfer of information between living entities, enabling them to perpetually glean information from the environment (= evolution. The next evolutionary milestone was the advent of cholesterol, embedded in the cell membranes of primordial eukaryotes, facilitating metabolism, oxygenation and locomotion, the triadic basis for vertebrate evolution. Lipids were key to homeostatic regulation of calcium, forming calcium channels. Cell membrane cholesterol also fostered metazoan evolution by forming lipid rafts for receptor-mediated cell-cell signaling, the origin of the endocrine system. The eukaryotic cell membrane exapted to all complex physiologic traits, including the lung and brain, which are molecularly homologous through the function of neuregulin, mediating both lung development and myelinization of neurons. That cooption later exapted as endothermy during the water-land transition (Torday JS. A Central Theory of Biology. Med Hypotheses. 2015 Jul;85(1:49-57, perhaps being the functional homolog for brain heat dissipation and consciousness/mind. The skin and brain similarly share molecular homologies through the ‘skin-brain’ hypothesis, giving insight to the cellular-molecular ‘arc’ of consciousness from its unicellular origins to integrated physiology. This perspective on the evolution of the central nervous system clarifies self-organization, reconciling thermodynamic and informational definitions of the underlying biophysical mechanisms, thereby elucidating relations between the

  5. Wireless Cellular Mobile Communications

    Directory of Open Access Journals (Sweden)

    V. Zalud

    2002-12-01

    Full Text Available In this article is briefly reviewed the history of wireless cellularmobile communications, examined the progress in current secondgeneration (2G cellular standards and discussed their migration to thethird generation (3G. The European 2G cellular standard GSM and itsevolution phases GPRS and EDGE are described somewhat in detail. Thethird generation standard UMTS taking up on GSM/GPRS core network andequipped with a new advanced access network on the basis of codedivision multiple access (CDMA is investigated too. A sketch of theperspective of mobile communication beyond 3G concludes this article.

  6. Integrated Transceivers for Millimeter Wave and Cellular Communication

    OpenAIRE

    TIRED, TOBIAS

    2016-01-01

    Abstract:This doctoral thesis is addresses two topics in integrated circuit design: multiband direct conversion cellular receivers for cellular frequencies and beam steering transmitters for millimeter wave communication for the cellular backhaul. The trend towards cellular terminals supporting ever more different frequency bands has resulted in complex radio frontends with a large number of RF inputs. Common receivers have, for performance reasons, in the past used differential RF inputs. Ho...

  7. Evo-SETI SCALE to measure Life on Exoplanets

    Science.gov (United States)

    Maccone, Claudio

    2016-04-01

    Darwinian Evolution over the last 3.5 billion years was an increase in the number of living species from 1 (RNA?) to the current 50 million. This increasing trend in time looks like being exponential, but one may not assume an exactly exponential curve since many species went extinct in the past, even in mass extinctions. Thus, the simple exponential curve must be replaced by a stochastic process having an exponential mean value. Borrowing from financial mathematics (;Black-Scholes models;), this ;exponential; stochastic process is called Geometric Brownian Motion (GBM), and its probability density function (pdf) is a lognormal (not a Gaussian) (Proof: see ref. Maccone [3], Chapter 30, and ref. Maccone [4]). Lognormal also is the pdf of the statistical number of communicating ExtraTerrestrial (ET) civilizations in the Galaxy at a certain fixed time, like a snapshot: this result was found in 2008 by this author as his solution to the Statistical Drake Equation of SETI (Proof: see ref. Maccone [1]). Thus, the GBM of Darwinian Evolution may also be regarded as the extension in time of the Statistical Drake equation (Proof: see ref. Maccone [4]). But the key step ahead made by this author in his Evo-SETI (Evolution and SETI) mathematical model was to realize that LIFE also is just a b-lognormal in time: every living organism (a cell, a human, a civilization, even an ET civilization) is born at a certain time b (;birth;), grows up to a peak p (with an ascending inflexion point in between, a for adolescence), then declines from p to s (senility, i.e. descending inflexion point) and finally declines linearly and dies at a final instant d (death). In other words, the infinite tail of the b-lognormal was cut away and replaced by just a straight line between s and d, leading to simple mathematical formulae (;History Formulae;) allowing one to find this ;finite b-lognormal; when the three instants b, s, and d are assigned. Next the crucial Peak-Locus Theorem comes. It means

  8. A man of his time: thorstein veblen and the university of chicago darwinists.

    Science.gov (United States)

    Raymer, Emilie J

    2013-01-01

    The Darwinian economic theory that Thorstein Veblen proposed and refined while he served as a professor of Political Economy at the University of Chicago from 1891 to 1906 should be assessed in the context of the community of Darwinian scientists and social scientists with whom Veblen worked and lived at Chicago. It is important to identify Veblen as a member of this broad community of Darwinian-inclined philosophers, physiologists, geologists, astronomers, and biologists at Chicago because Veblen's involvement with this circle suggests that the possible sources of his engagement with Darwinism extend beyond the pragmatists and Continental socialists to whom scholars have typically ascribed Veblen's Darwinian roots. Additionally, that an extensive community continued to use Darwinian evolutionary theory to construct new models of scientific and social scientific analysis at the turn of the twentieth century, a period during which Darwinism was purportedly in decline, suggests that the "eclipse of Darwinism" narrative has been overstated in literature about Darwinism's intellectual arc.

  9. The Brazilian Theory of Habeas Corpus for Great Apes

    Directory of Open Access Journals (Sweden)

    Heron José de Santana Gordilho

    2016-06-01

    Full Text Available This essay presents a comparison between human evolution and legal developments, trying to demonstrate how darwinian theory of evolution by natural selection has caused changes in the legal world, the bridge of today some lawyers using the recent discoveries about how similar genetic between man and great primates to claim extension of human rights for chimpanzees, bonobos, gorillas and orangs. It also that many activists for animal`s rights have considered the dispute an important strategy, whether to set new means for legal institutes such as the Habeas Corpus, hitherto used only to ensure human freedom, whether to increase the movement and increase the conscietization of the general population about the importance of the recognition of animals as holders of basic rights.

  10. Biodiversity

    International Nuclear Information System (INIS)

    Gomez Giraldo; Luis Jair

    2011-01-01

    Biodiversity is a really surprising ecological event, as long as there is an extraordinary chemical and biochemical homogeneity at the very foundation of all living beings. It is believed that there are at least three phenomena that may explain it: Darwinian evolution, that is a kind of ramifying evolution; structural coupling, as defined by H. Maturana; and, finally, thermodynamical phenomena, as presented by S. Kauffman leaning on the concepts of organization and a propagating organization that diversifies, and they are all interpreted by E. D. Schneider and J. J. Kay from the idea of Earth as a thermodynamical system. The explanatory importance of this idea in the current environmental crisis, evident in other events such as global warming, is of great relevance.

  11. Toxicity of pyrolysis gases from some cellular polymers

    Science.gov (United States)

    Hilado, C. J.; Machado, A. M.

    1978-01-01

    Various samples of cellular polymers were evaluated for toxicity of pyrolysis gases, using the screening test method developed at the University of San Francisco. The cellular polymer samples included polyimide, polymethacrylimide, polybismaleimide, polyurethane, polyisocyanurate, polyethylene, polychloroprene, polyvinyl chloride, polystyrene, polysiloxane, and polyphosphazene. The cellular polymers exhibited varying levels of toxicity under these test conditions. Among the rigid cellular polymers, times to death were shortest with the imide type foams and longest with polyvinyl chloride and polystyrene. Among the flexible cellular polymers, times to death were shortest with polyimide and polyester, and longest with polychloroprene and polysiloxane. Increased char yield was not necessarily associated with reduced toxicity.

  12. Cellular telephone use and cancer risk

    DEFF Research Database (Denmark)

    Schüz, Joachim; Jacobsen, Rune; Olsen, Jørgen H.

    2006-01-01

    BACKGROUND: The widespread use of cellular telephones has heightened concerns about possible adverse health effects. The objective of this study was to investigate cancer risk among Danish cellular telephone users who were followed for up to 21 years. METHODS: This study is an extended follow......-up of a large nationwide cohort of 420,095 persons whose first cellular telephone subscription was between 1982 and 1995 and who were followed through 2002 for cancer incidence. Standardized incidence ratios (SIRs) were calculated by dividing the number of observed cancer cases in the cohort by the number...... expected in the Danish population. RESULTS: A total of 14,249 cancers were observed (SIR = 0.95; 95% confidence interval [CI] = 0.93 to 0.97) for men and women combined. Cellular telephone use was not associated with increased risk for brain tumors (SIR = 0.97), acoustic neuromas (SIR = 0.73), salivary...

  13. Wavefront cellular learning automata.

    Science.gov (United States)

    Moradabadi, Behnaz; Meybodi, Mohammad Reza

    2018-02-01

    This paper proposes a new cellular learning automaton, called a wavefront cellular learning automaton (WCLA). The proposed WCLA has a set of learning automata mapped to a connected structure and uses this structure to propagate the state changes of the learning automata over the structure using waves. In the WCLA, after one learning automaton chooses its action, if this chosen action is different from the previous action, it can send a wave to its neighbors and activate them. Each neighbor receiving the wave is activated and must choose a new action. This structure for the WCLA is necessary in many dynamic areas such as social networks, computer networks, grid computing, and web mining. In this paper, we introduce the WCLA framework as an optimization tool with diffusion capability, study its behavior over time using ordinary differential equation solutions, and present its accuracy using expediency analysis. To show the superiority of the proposed WCLA, we compare the proposed method with some other types of cellular learning automata using two benchmark problems.

  14. Wavefront cellular learning automata

    Science.gov (United States)

    Moradabadi, Behnaz; Meybodi, Mohammad Reza

    2018-02-01

    This paper proposes a new cellular learning automaton, called a wavefront cellular learning automaton (WCLA). The proposed WCLA has a set of learning automata mapped to a connected structure and uses this structure to propagate the state changes of the learning automata over the structure using waves. In the WCLA, after one learning automaton chooses its action, if this chosen action is different from the previous action, it can send a wave to its neighbors and activate them. Each neighbor receiving the wave is activated and must choose a new action. This structure for the WCLA is necessary in many dynamic areas such as social networks, computer networks, grid computing, and web mining. In this paper, we introduce the WCLA framework as an optimization tool with diffusion capability, study its behavior over time using ordinary differential equation solutions, and present its accuracy using expediency analysis. To show the superiority of the proposed WCLA, we compare the proposed method with some other types of cellular learning automata using two benchmark problems.

  15. Spanish Darwinian iconography: Darwin and evolutionism portrayed in Spanish press cartoons.

    Science.gov (United States)

    Domínguez, Martí; Mateu, Anna

    2013-11-01

    The theory of evolution has played a major role in the press since it was put forward by Charles Darwin in 1859. Its key role in biology and human philosophy is reflected by its presence in press cartoons, sections where the image of social reality is depicted in a more direct and satirical light. Through cartoons, artists have used their ingenuity or wit to portray one of the most controversial scientific figures of the past two centuries. This study examines the views portrayed by Spanish cartoonists about Charles Darwin and evolutionary theory in 2009, the bicentenary of the naturalist's birth and the celebration of 150 years since the publication of On the Origin of Species. These cartoons show how the controversy between Darwinism and religion remain latent in the heart of Spanish society, and how the figure of Darwin has become one of the main icons of science.

  16. Novel Materials for Cellular Nanosensors

    DEFF Research Database (Denmark)

    Sasso, Luigi

    The monitoring of cellular behavior is useful for the advancement of biomedical diagnostics, drug development and the understanding of a cell as the main unit of the human body. Micro- and nanotechnology allow for the creation of functional devices that enhance the study of cellular dynamics...... modifications for electrochemical nanosensors for the detection of analytes released from cells. Two type of materials were investigated, each pertaining to the two different aspects of such devices: peptide nanostructures were studied for the creation of cellular sensing substrates that mimic in vivo surfaces...... and that offer advantages of functionalization, and conducting polymers were used as electrochemical sensor surface modifications for increasing the sensitivity towards relevant analytes, with focus on the detection of dopamine released from cells via exocytosis. Vertical peptide nanowires were synthesized from...

  17. Molecular evolution of the hyperthermophilic archaea of the Pyrococcus genus: analysis of adaptation to different environmental conditions

    Directory of Open Access Journals (Sweden)

    Afonnikov Dmitry A

    2009-12-01

    Full Text Available Abstract Background Prokaryotic microorganisms are able to survive and proliferate in severe environmental conditions. The increasing number of complete sequences of prokaryotic genomes has provided the basis for studying the molecular mechanisms of their adaptation at the genomic level. We apply here a computer-based approach to compare the genomes and proteomes from P. furiosus, P. horikoshii, and P. abyssi to identify features of their molecular evolution related to adaptation strategy to diverse environmental conditions. Results Phylogenetic analysis of rRNA genes from 26 Pyrococcus strains suggested that the divergence of P. furiosus, P. horikoshii and P. abyssi might have occurred from ancestral deep-sea organisms. It was demonstrated that the function of genes that have been subject to positive Darwinian selection is closely related to abiotic and biotic conditions to which archaea managed to become adapted. Divergence of the P. furiosus archaea might have been due to loss of some genes involved in cell motility or signal transduction, and/or to evolution under positive selection of the genes for translation machinery. In the course of P. horikoshii divergence, positive selection was found to operate mainly on the transcription machinery; divergence of P. abyssi was related with positive selection for the genes mainly involved in inorganic ion transport. Analysis of radical amino acid replacement rate in evolving P. furiosus, P. horikoshii and P. abyssi showed that the fixation rate was higher for radical substitutions relative to the volume of amino acid side-chain. Conclusions The current results give due credit to the important role of hydrostatic pressure as a cause of variability in the P. furiosus, P. horikoshii and P. abyssi genomes evolving in different habitats. Nevertheless, adaptation to pressure does not appear to be the sole factor ensuring adaptation to environment. For example, at the stage of the divergence of P

  18. The evolutionary sequence: origin and emergences

    Science.gov (United States)

    Fox, S. W.

    1986-01-01

    The evolutionary sequence is being reexamined experimentally from a "Big Bang"origin to the protocell and from the emergence of protocell and variety of species to Darwin's mental power (mind) and society (The Descent of Man). A most fundamentally revisionary consequence of experiments is an emphasis on endogenous ordering. This principle, seen vividly in ordered copolymerization of amino acids, has had new impact on the theory of Darwinian evolution and has been found to apply to the entire sequence. Herein, I will discuss some problems of dealing with teaching controversial subjects.

  19. Lloyd Morgan's theory of instinct: from Darwinism to neo-Darwinism.

    Science.gov (United States)

    Richards, R J

    1977-01-01

    Darwin's proposal of two sources of instinct--natural selection and inherited habit--fostered among late nineteenth century evolutionists a variety of conflicting notions concerning the mechanisms of evolution. The British comparative psychologist C. Lloyd Morgan was a cardinal figure in restructuring the orthodox Darwinian conception to relieve the confusion besetting it and to meet the demands of the new biology of Weismann. This paper traces the development of Morgan's ideas about instinct against the background of his philosophic assumptions and the views of instinct theorists from Darwin and Romanes to McDougall and Lorenz.

  20. The evolutionary sequence: origin and emergences.

    Science.gov (United States)

    Fox, S W

    1986-03-01

    The evolutionary sequence is being reexamined experimentally from a "Big Bang"origin to the protocell and from the emergence of protocell and variety of species to Darwin's mental power (mind) and society (The Descent of Man). A most fundamentally revisionary consequence of experiments is an emphasis on endogenous ordering. This principle, seen vividly in ordered copolymerization of amino acids, has had new impact on the theory of Darwinian evolution and has been found to apply to the entire sequence. Herein, I will discuss some problems of dealing with teaching controversial subjects.

  1. Agent-Based Modeling of Mitochondria Links Sub-Cellular Dynamics to Cellular Homeostasis and Heterogeneity.

    Directory of Open Access Journals (Sweden)

    Giovanni Dalmasso

    Full Text Available Mitochondria are semi-autonomous organelles that supply energy for cellular biochemistry through oxidative phosphorylation. Within a cell, hundreds of mobile mitochondria undergo fusion and fission events to form a dynamic network. These morphological and mobility dynamics are essential for maintaining mitochondrial functional homeostasis, and alterations both impact and reflect cellular stress states. Mitochondrial homeostasis is further dependent on production (biogenesis and the removal of damaged mitochondria by selective autophagy (mitophagy. While mitochondrial function, dynamics, biogenesis and mitophagy are highly-integrated processes, it is not fully understood how systemic control in the cell is established to maintain homeostasis, or respond to bioenergetic demands. Here we used agent-based modeling (ABM to integrate molecular and imaging knowledge sets, and simulate population dynamics of mitochondria and their response to environmental energy demand. Using high-dimensional parameter searches we integrated experimentally-measured rates of mitochondrial biogenesis and mitophagy, and using sensitivity analysis we identified parameter influences on population homeostasis. By studying the dynamics of cellular subpopulations with distinct mitochondrial masses, our approach uncovered system properties of mitochondrial populations: (1 mitochondrial fusion and fission activities rapidly establish mitochondrial sub-population homeostasis, and total cellular levels of mitochondria alter fusion and fission activities and subpopulation distributions; (2 restricting the directionality of mitochondrial mobility does not alter morphology subpopulation distributions, but increases network transmission dynamics; and (3 maintaining mitochondrial mass homeostasis and responding to bioenergetic stress requires the integration of mitochondrial dynamics with the cellular bioenergetic state. Finally, (4 our model suggests sources of, and stress conditions

  2. Cellularity of certain quantum endomorphism algebras

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Lehrer, G. I.; Zhang, R.

    Let $\\tA=\\Z[q^{\\pm \\frac{1}{2}}][([d]!)\\inv]$ and let $\\Delta_{\\tA}(d)$ be an integral form of the Weyl module of highest weight $d \\in \\N$ of the quantised enveloping algebra $\\U_{\\tA}$ of $\\fsl_2$. We exhibit for all positive integers $r$ an explicit cellular structure for $\\End...... of endomorphism algebras, and another which relates the multiplicities of indecomposable summands to the dimensions of simple modules for an endomorphism algebra. Our cellularity result then allows us to prove that knowledge of the dimensions of the simple modules of the specialised cellular algebra above...

  3. Selection Finder (SelFi: A computational metabolic engineering tool to enable directed evolution of enzymes

    Directory of Open Access Journals (Sweden)

    Neda Hassanpour

    2017-06-01

    Full Text Available Directed evolution of enzymes consists of an iterative process of creating mutant libraries and choosing desired phenotypes through screening or selection until the enzymatic activity reaches a desired goal. The biggest challenge in directed enzyme evolution is identifying high-throughput screens or selections to isolate the variant(s with the desired property. We present in this paper a computational metabolic engineering framework, Selection Finder (SelFi, to construct a selection pathway from a desired enzymatic product to a cellular host and to couple the pathway with cell survival. We applied SelFi to construct selection pathways for four enzymes and their desired enzymatic products xylitol, D-ribulose-1,5-bisphosphate, methanol, and aniline. Two of the selection pathways identified by SelFi were previously experimentally validated for engineering Xylose Reductase and RuBisCO. Importantly, SelFi advances directed evolution of enzymes as there is currently no known generalized strategies or computational techniques for identifying high-throughput selections for engineering enzymes.

  4. Influence of extra-cellular and intra-cellular acting thiol oxidants on the 45calcium uptake by the islets of Langerhans of the rat

    International Nuclear Information System (INIS)

    Haegele, R.G.

    1981-01-01

    The glucose-stimulated calcium uptake by the islets of Langerhans is dependent on the intra-cellular GSH/GSSG ratios. The inhibition of calcium uptake is not the consequence of a direct oxidation of membrane-fixed thiol groups. In contrast, direct oxidation of extra cellular thiols leads to an increase in calcium uptake when intra-cellular oxidation is simultaneously prevented. Since this effect only occurs at high intra-cellular GSH/GSSG ratios it can be assumed that the redox state of extra-cellular thiols is dependent on the redox state of the intra-cellular GSH/GSSG ratios. These findings support the theory that the oxidation of extra-cellular thiols by thiol oxidants leads to an increase in calcium uptake and that the extent of uptake is higher, the more the redox state of the extra-cellular thiols tends towards the reduced state prior to oxidation. (orig./MG) [de

  5. Modems for emerging digital cellular-mobile radio system

    Science.gov (United States)

    Feher, Kamilo

    1991-01-01

    Digital modem techniques for emerging digital cellular telecommunications-mobile radio system applications are described and analyzed. In particular, theoretical performance, experimental results, principles of operation, and various architectures of pi/4-QPSK (pi/4-shifted coherent or differential QPSK) modems for second-generation US digital cellular radio system applications are presented. The spectral/power efficiency and performance of the pi/4-QPSK modems (American and Japanese digital cellular emerging standards) are studied and briefly compared to GMSK (Gaussian minimum-shift keying) modems (proposed for European DECT and GSM cellular standards). Improved filtering strategies and digital pilot-aided (digital channel sounding) techniques are also considered for pi/4-QPSK and other digital modems. These techniques could significantly improve the performance of digital cellular and other digital land mobile and satellite mobile radio systems. More spectrally efficient modem trends for future cellular/mobile (land mobile) and satellite communication systems applications are also highlighted.

  6. Cellular-automata supercomputers for fluid-dynamics modeling

    International Nuclear Information System (INIS)

    Margolus, N.; Toffoli, T.; Vichniac, G.

    1986-01-01

    We report recent developments in the modeling of fluid dynamics, and give experimental results (including dynamical exponents) obtained using cellular automata machines. Because of their locality and uniformity, cellular automata lend themselves to an extremely efficient physical realization; with a suitable architecture, an amount of hardware resources comparable to that of a home computer can achieve (in the simulation of cellular automata) the performance of a conventional supercomputer

  7. Iron Oxide Nanoparticles Stimulates Extra-Cellular Matrix Production in Cellular Spheroids

    Directory of Open Access Journals (Sweden)

    Megan Casco

    2017-01-01

    Full Text Available Nanotechnologies have been integrated into drug delivery, and non-invasive imaging applications, into nanostructured scaffolds for the manipulation of cells. The objective of this work was to determine how the physico-chemical properties of magnetic nanoparticles (MNPs and their spatial distribution into cellular spheroids stimulated cells to produce an extracellular matrix (ECM. The MNP concentration (0.03 mg/mL, 0.1 mg/mL and 0.3 mg/mL, type (magnetoferritin, shape (nanorod—85 nm × 425 nm and incorporation method were studied to determine each of their effects on the specific stimulation of four ECM proteins (collagen I, collagen IV, elastin and fibronectin in primary rat aortic smooth muscle cell. Results demonstrated that as MNP concentration increased there was up to a 6.32-fold increase in collagen production over no MNP samples. Semi-quantitative Immunohistochemistry (IHC results demonstrated that MNP type had the greatest influence on elastin production with a 56.28% positive area stain compared to controls and MNP shape favored elastin stimulation with a 50.19% positive area stain. Finally, there are no adverse effects of MNPs on cellular contractile ability. This study provides insight on the stimulation of ECM production in cells and tissues, which is important because it plays a critical role in regulating cellular functions.

  8. Energetic evolution of cellular Transportomes

    DEFF Research Database (Denmark)

    Darbani, Behrooz; Kell, Douglas B.; Borodina, Irina

    2018-01-01

    of the transition from prokaryotes to eukaryotes. The transportome analysis also indicated seven bacterial species, including Neorickettsia risticii and Neorickettsia sennetsu, as likely origins of the mitochondrion in eukaryotes, based on the phylogenetically restricted presence therein of clear homologues......) than in primitive eukaryotes (13%), algae and plants (10%) and in fungi and animals (5–6%). This decrease is compensated by an increased occurrence of secondary transporters and ion channels. The share of ion channels is particularly high in animals (ca. 30% of the transportome) and algae and plants...... of modern mitochondrial solute carriers. Conclusions: The results indicate that the transportomes of eukaryotes evolved strongly towards a higher energetic efficiency, as ATP-dependent transporters diminished and secondary transporters and ion channels proliferated. These changes have likely been important...

  9. Analysis of Human Mobility Based on Cellular Data

    Science.gov (United States)

    Arifiansyah, F.; Saptawati, G. A. P.

    2017-01-01

    Nowadays not only adult but even teenager and children have then own mobile phones. This phenomena indicates that the mobile phone becomes an important part of everyday’s life. Based on these indication, the amount of cellular data also increased rapidly. Cellular data defined as the data that records communication among mobile phone users. Cellular data is easy to obtain because the telecommunications company had made a record of the data for the billing system of the company. Billing data keeps a log of the users cellular data usage each time. We can obtained information from the data about communication between users. Through data visualization process, an interesting pattern can be seen in the raw cellular data, so that users can obtain prior knowledge to perform data analysis. Cellular data processing can be done using data mining to find out human mobility patterns and on the existing data. In this paper, we use frequent pattern mining and finding association rules to observe the relation between attributes in cellular data and then visualize them. We used weka tools for finding the rules in stage of data mining. Generally, the utilization of cellular data can provide supporting information for the decision making process and become a data support to provide solutions and information needed by the decision makers.

  10. Cellular modeling of fault-tolerant multicomputers

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, G

    1987-01-01

    Work described was concerned with a novel method for investigation of fault tolerance in large regular networks of computers. Motivation was to provide a technique useful in rapid evaluation of highly reliable systems that exploit the low cost and ease of volume production of simple microcomputer components. First, a system model and simulator based upon cellular automata are developed. This model is characterized by its simplicity and ease of modification when adapting to new types of network. Second, in order to test and verify the predictive capabilities of the cellular system, a more-detailed simulation is performed based upon an existing computational model, that of the Transputer. An example application is used to exercise various systems designed using the cellular model. Using this simulator, experimental results are obtained both for existing well-understood configurations and for more novel types also developed here. In all cases it was found that the cellular model and simulator successfully predicted the ranking in reliability improvement of the systems studied.

  11. An Urban Cellular Automata Model for Simulating Dynamic States on a Local Scale

    Directory of Open Access Journals (Sweden)

    Jenni Partanen

    2016-12-01

    Full Text Available In complex systems, flexibility and adaptability to changes are crucial to the systems’ dynamic stability and evolution. Such resilience requires that the system is able to respond to disturbances by self-organizing, which implies a certain level of entropy within the system. Dynamic states (static, cyclical/periodic, complex, and chaotic reflect this generative capacity, and correlate with the level of entropy. For planning complex cities, we need to develop methods to guide such autonomous progress in an optimal manner. A classical apparatus, cellular automaton (CA, provides such a tool. Applications of CA help us to study temporal dynamics in self-organizing urban systems. By exploring the dynamic states of the model’s dynamics resulting from different border conditions it is possible to discover favorable set(s of rules conductive to the self-organizing dynamics and enable the system’s recovery at the time of crises. Level of entropy is a relevant measurement for evaluation of these dynamic states. The 2-D urban cellular automaton model studied here is based on the microeconomic principle that similar urban activities are attracted to each other, especially in certain self-organizing areas, and that the local dynamics of these enclaves affect the dynamics of the urban region by channeling flows of information, goods and people. The results of the modeling experiment indicate that the border conditions have a major impact on the model’s dynamics generating various dynamic states of the system. Most importantly, it seemed that the model could simulate a favorable, complex dynamic state with medium entropy level which may refer to the continuous self-organization of the system. The model provides a tool for exploring and understanding the effects of boundary conditions in the planning process as various scenarios are tested: resulting dynamics of the system can be explored with such “planning rules” prior to decisions, helping to

  12. The sexual cascade and the rise of pre-ejaculatory (Darwinian) sexual selection, sex roles, and sexual conflict.

    Science.gov (United States)

    Parker, Geoff A

    2014-08-21

    After brief historic overviews of sexual selection and sexual conflict, I argue that pre-ejaculatory sexual selection (the form of sexual selection discussed by Darwin) arose at a late stage in an inevitable succession of transitions flowing from the early evolution of syngamy to the evolution of copulation and sex roles. If certain conditions were met, this "sexual cascade" progressed inevitably, if not, sexual strategy remained fixed at a given stage. Prolonged evolutionary history of intense sperm competition/selection under external fertilization preceded the rise of advanced mobility, which generated pre-ejaculatory sexual selection, followed on land by internal fertilization and reduced sperm competition in the form of postcopulatory sexual selection. I develop a prospective model of the early evolution of mobility, which, as Darwin realized, was the catalyst for pre-ejaculatory sexual selection. Stages in the cascade should be regarded as consequential rather than separate phenomena and, as such, invalidate much current opposition to Darwin-Bateman sex roles. Potential for sexual conflict occurs throughout, greatly increasing later in the cascade, reaching its peak under precopulatory sexual selection when sex roles become highly differentiated. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

  13. A radiation measurement study on cellular phone

    International Nuclear Information System (INIS)

    Mohd Yusof Mohd Ali; Rozaimah Abd Rahim; Roha Tukimin; Khairol Nizam Mohamed; Mohd Amirul Nizam Mohamad Thari; Ahmad Fadzli Ahmad Sanusi

    2007-01-01

    This paper will explain the radiation level produced by various selected cellular phone from various models and brands available in the market. The result obtained from this study will also recommend whether a cellular phone is safe for public usage or it might cause any effect on public health. Finally, a database of radiation measurement level produced by selected various cellular phone will also be developed and exhibited in this paper. (Author)

  14. Hippocampus minor and man's place in nature: a case study in the social construction of neuroanatomy.

    Science.gov (United States)

    Gross, C G

    1993-10-01

    In mid-19th century Britain the possibility of evolution and particularly the evolution of man from apes was vigorously contested. Among the leading antievolutionists was the celebrated anatomist and paleontologist Richard Owen and among the leading defenders of evolution was Thomas Henry Huxley. The central dispute between them on human evolution was whether or not man's brain was fundamentally unique in having a hippocampus minor (known today as the calcar avis), a posterior horn in the lateral ventricle, and a posterior lobe. The author considers the background of this controversy, the origin and fate of the term hippocampus minor, why this structure became central to the question of human evolution, and how Huxley used it to support both Darwinism and the political ascendancy of Darwinians. The use of ventricular structures to distinguish humans from other animals appears to reflect an importance given to the ventricles that stretches back to ancient Greek medicine. This account illustrates both the extraordinary persistence of ideas in biology and the role of the political and social matrix in the study of the brain.

  15. Interplay between chaperones and protein disorder promotes the evolution of protein networks.

    Directory of Open Access Journals (Sweden)

    Sebastian Pechmann

    2014-06-01

    importance of the cellular context and integrated approaches for understanding proteome evolution. We feel that the development of λ may be a valuable addition to the toolbox applied to understand the molecular basis of evolution.

  16. 1,4-Naphthoquinones: From Oxidative Damage to Cellular and Inter-Cellular Signaling

    Directory of Open Access Journals (Sweden)

    Lars-Oliver Klotz

    2014-09-01

    Full Text Available Naphthoquinones may cause oxidative stress in exposed cells and, therefore, affect redox signaling. Here, contributions of redox cycling and alkylating properties of quinones (both natural and synthetic, such as plumbagin, juglone, lawsone, menadione, methoxy-naphthoquinones, and others to cellular and inter-cellular signaling processes are discussed: (i naphthoquinone-induced Nrf2-dependent modulation of gene expression and its potentially beneficial outcome; (ii the modulation of receptor tyrosine kinases, such as the epidermal growth factor receptor by naphthoquinones, resulting in altered gap junctional intercellular communication. Generation of reactive oxygen species and modulation of redox signaling are properties of naphthoquinones that render them interesting leads for the development of novel compounds of potential use in various therapeutic settings.

  17. Cellular-automata method for phase unwrapping

    International Nuclear Information System (INIS)

    Ghiglia, D.C.; Mastin, G.A.; Romero, L.A.

    1987-01-01

    Research into two-dimensional phase unwrapping has uncovered interesting and troublesome inconsistencies that cause path-dependent results. Cellular automata, which are simple, discrete mathematical systems, offered promise of computation in nondirectional, parallel manner. A cellular automaton was discovered that can unwrap consistent phase data in n dimensions in a path-independent manner and can automatically accommodate noise-induced (pointlike) inconsistencies and arbitrary boundary conditions (region partitioning). For data with regional (nonpointlike) inconsistencies, no phase-unwrapping algorithm will converge, including the cellular-automata approach. However, the automata method permits more simple visualization of the regional inconsistencies. Examples of its behavior on one- and two-dimensional data are presented

  18. A cryptosystem based on elementary cellular automata

    Science.gov (United States)

    Abdo, A. A.; Lian, Shiguo; Ismail, I. A.; Amin, M.; Diab, H.

    2013-01-01

    Based on elementary cellular automata, a new image encryption algorithm is proposed in this paper. In this algorithm, a special kind of periodic boundary cellular automata with unity attractors is used. From the viewpoint of security, the number of cellular automata attractor states are changed with respect to the encrypted image, and different key streams are used to encrypt different plain images. The cellular neural network with chaotic properties is used as the generator of a pseudo-random key stream. Theoretical analysis and experimental results have both confirmed that the proposed algorithm possesses high security level and good performances against differential and statistical attacks. The comparison with other existing schemes is given, which shows the superiority of the proposal scheme.

  19. Nested cellular automata

    International Nuclear Information System (INIS)

    Quasthoff, U.

    1985-07-01

    Cellular automata by definition consist of a finite or infinite number of cells, say of unit length, with each cell having the same transition function. These cells are usually considered as the smallest elements and so the space filled with these cells becomes discrete. Nevertheless, large pictures created by such cellular automata look very fractal. So we try to replace each cell by a couple of smaller cells, which have the same transition functions as the large ones. There are automata where this replacement does not destroy the macroscopic structure. In these cases this nesting process can be iterated. The paper contains large classes of automata with the above properties. In the case of one dimensional automata with two states and next neighbour interaction and a nesting function of the same type a complete classification is given. (author)

  20. Environment Aware Cellular Networks

    KAUST Repository

    Ghazzai, Hakim

    2015-02-01

    The unprecedented rise of mobile user demand over the years have led to an enormous growth of the energy consumption of wireless networks as well as the greenhouse gas emissions which are estimated currently to be around 70 million tons per year. This significant growth of energy consumption impels network companies to pay huge bills which represent around half of their operating expenditures. Therefore, many service providers, including mobile operators, are looking for new and modern green solutions to help reduce their expenses as well as the level of their CO2 emissions. Base stations are the most power greedy element in cellular networks: they drain around 80% of the total network energy consumption even during low traffic periods. Thus, there is a growing need to develop more energy-efficient techniques to enhance the green performance of future 4G/5G cellular networks. Due to the problem of traffic load fluctuations in cellular networks during different periods of the day and between different areas (shopping or business districts and residential areas), the base station sleeping strategy has been one of the main popular research topics in green communications. In this presentation, we present several practical green techniques that provide significant gains for mobile operators. Indeed, combined with the base station sleeping strategy, these techniques achieve not only a minimization of the fossil fuel consumption but also an enhancement of mobile operator profits. We start with an optimized cell planning method that considers varying spatial and temporal user densities. We then use the optimal transport theory in order to define the cell boundaries such that the network total transmit power is reduced. Afterwards, we exploit the features of the modern electrical grid, the smart grid, as a new tool of power management for cellular networks and we optimize the energy procurement from multiple energy retailers characterized by different prices and pollutant

  1. Theoretical aspects of cellular decision-making and information-processing.

    Science.gov (United States)

    Kobayashi, Tetsuya J; Kamimura, Atsushi

    2012-01-01

    Microscopic biological processes have extraordinary complexity and variety at the sub-cellular, intra-cellular, and multi-cellular levels. In dealing with such complex phenomena, conceptual and theoretical frameworks are crucial, which enable us to understand seemingly different intra- and inter-cellular phenomena from unified viewpoints. Decision-making is one such concept that has attracted much attention recently. Since a number of cellular behavior can be regarded as processes to make specific actions in response to external stimuli, decision-making can cover and has been used to explain a broad range of different cellular phenomena [Balázsi et al. (Cell 144(6):910, 2011), Zeng et al. (Cell 141(4):682, 2010)]. Decision-making is also closely related to cellular information-processing because appropriate decisions cannot be made without exploiting the information that the external stimuli contain. Efficiency of information transduction and processing by intra-cellular networks determines the amount of information obtained, which in turn limits the efficiency of subsequent decision-making. Furthermore, information-processing itself can serve as another concept that is crucial for understanding of other biological processes than decision-making. In this work, we review recent theoretical developments on cellular decision-making and information-processing by focusing on the relation between these two concepts.

  2. The cellular approach to band structure calculations

    International Nuclear Information System (INIS)

    Verwoerd, W.S.

    1982-01-01

    A short introduction to the cellular approach in band structure calculations is given. The linear cellular approach and its potantial applicability in surface structure calculations is given some consideration in particular

  3. Insights from amphioxus into the evolution of vertebrate cartilage.

    Directory of Open Access Journals (Sweden)

    Daniel Meulemans

    2007-08-01

    Full Text Available Central to the story of vertebrate evolution is the origin of the vertebrate head, a problem difficult to approach using paleontology and comparative morphology due to a lack of unambiguous intermediate forms. Embryologically, much of the vertebrate head is derived from two ectodermal tissues, the neural crest and cranial placodes. Recent work in protochordates suggests the first chordates possessed migratory neural tube cells with some features of neural crest cells. However, it is unclear how and when these cells acquired the ability to form cellular cartilage, a cell type unique to vertebrates. It has been variously proposed that the neural crest acquired chondrogenic ability by recruiting proto-chondrogenic gene programs deployed in the neural tube, pharynx, and notochord. To test these hypotheses we examined the expression of 11 amphioxus orthologs of genes involved in neural crest chondrogenesis. Consistent with cellular cartilage as a vertebrate novelty, we find that no single amphioxus tissue co-expresses all or most of these genes. However, most are variously co-expressed in mesodermal derivatives. Our results suggest that neural crest-derived cartilage evolved by serial cooption of genes which functioned primitively in mesoderm.

  4. Some Properties of topological pressure on cellular automata

    Directory of Open Access Journals (Sweden)

    Chih-Hung Chang

    2014-09-01

    Full Text Available This paper investigates the ergodicity and the power rule of the topological pressure of a cellular automaton. If a cellular automaton is either leftmost or rightmost premutive (due to the terminology given by Hedlund [Math.~Syst.~Theor.~3, 320-375, 1969], then it is ergodic with respect to the uniform Bernoulli measure. More than that, the relation of topological pressure between the original cellular automaton and its power rule is expressed in a closed form. As an application, the topological pressure of a linear cellular automaton can be computed explicitly.

  5. SINEs as driving forces in genome evolution.

    Science.gov (United States)

    Schmitz, J

    2012-01-01

    SINEs are short interspersed elements derived from cellular RNAs that repetitively retropose via RNA intermediates and integrate more or less randomly back into the genome. SINEs propagate almost entirely vertically within their host cells and, once established in the germline, are passed on from generation to generation. As non-autonomous elements, their reverse transcription (from RNA to cDNA) and genomic integration depends on the activity of the enzymatic machinery of autonomous retrotransposons, such as long interspersed elements (LINEs). SINEs are widely distributed in eukaryotes, but are especially effectively propagated in mammalian species. For example, more than a million Alu-SINE copies populate the human genome (approximately 13% of genomic space), and few master copies of them are still active. In the organisms where they occur, SINEs are a challenge to genomic integrity, but in the long term also can serve as beneficial building blocks for evolution, contributing to phenotypic heterogeneity and modifying gene regulatory networks. They substantially expand the genomic space and introduce structural variation to the genome. SINEs have the potential to mutate genes, to alter gene expression, and to generate new parts of genes. A balanced distribution and controlled activity of such properties is crucial to maintaining the organism's dynamic and thriving evolution. Copyright © 2012 S. Karger AG, Basel.

  6. Advanced 3D Printers for Cellular Solids

    Science.gov (United States)

    2016-06-30

    06-2016 1-Aug-2014 31-Dec-2015 Final Report: Advanced 3D printers for Cellular Solids The views, opinions and/or findings contained in this report are...2211 3d printing, cellular solids REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 10. SPONSOR/MONITOR’S ACRONYM(S) ARO 8...Papers published in non peer-reviewed journals: Final Report: Advanced 3D printers for Cellular Solids Report Title Final Report for DURIP grant W911NF

  7. On Elementary and Algebraic Cellular Automata

    Science.gov (United States)

    Gulak, Yuriy

    In this paper we study elementary cellular automata from an algebraic viewpoint. The goal is to relate the emergent complex behavior observed in such systems with the properties of corresponding algebraic structures. We introduce algebraic cellular automata as a natural generalization of elementary ones and discuss their applications as generic models of complex systems.

  8. Johannsen's criticism of the chromosome theory.

    Science.gov (United States)

    Roll-Hansen, Nils

    2014-01-01

    The genotype theory of Wilhelm Johannsen (1857-1927) was an important contribution to the founding of classical genetics. This theory built on Johannsen's experimental demonstration that hereditary change is discontinuous, not continuous as had been widely assumed. Johannsen is also known for his criticism of traditional Darwinian evolution by natural selection, as well as his criticism of the classical Mendelian chromosome theory of heredity. He has often been seen as one of the anti-Darwinians that caused the "eclipse of Darwinism" in the early 20th century, before it was saved by the Modern Synthesis. This article focuses on Johannsen's criticism of the chromosome theory. He was indeed skeptical of the notion of the chromosomes as the sole carriers of heredity, but he praised the mapping of Mendelian genes on the chromosomes as a major step forward. Johannsen objected that these genes could not account for the whole of heredity, and that the stability of the genotype depended on much more than the stability of Mendelian genes. For Johannsen, the genotype, as a property of the whole organism, was the fundamental and empirically well-established entity.

  9. Adaptive Antenna System for Both 4G LTE and 5G Cellular Systems

    Science.gov (United States)

    Henderson, Kendrick Q. T.

    Given the steep increase in the use of mobile communication systems, the current 4G/LTE (Long Term Evolution), cellular system will not be able to handle the increase in data. It is estimated that by 2020 the bandwidth requirements will be 10 times greater than what LTE can sustain. A new 5th generation (5G) communication system has been proposed to meet this demand. The physical layer or the antenna is the most critical part of any wireless communication systems as it is the interface between the free space medium and an electrical circuit. It sets the margin for almost all design parameters in the system such as the system noise and bandwidth. Several interactions of antennas have been proposed over the years for cellular services. These antennas are of various geometries, bandwidths, and radiation patterns with almost all having linear polarization. This thesis attempts to solve the multiple LTE antenna problem by creating a simple antenna that covers most of the LTE bands (850-2700 MHz) as well as introducing an antenna system at the 28 GHz 5G band. This allows for a greater educated hypothesis into what 5G can offer at the physical layer. The proposed concept will provide a solution to the co-existence problem of upcoming 5G wireless systems to be interoperable with existing 4G/LTE system.

  10. Cellularized Cellular Solids via Freeze-Casting.

    Science.gov (United States)

    Christoph, Sarah; Kwiatoszynski, Julien; Coradin, Thibaud; Fernandes, Francisco M

    2016-02-01

    The elaboration of metabolically active cell-containing materials is a decisive step toward the successful application of cell based technologies. The present work unveils a new process allowing to simultaneously encapsulate living cells and shaping cell-containing materials into solid-state macroporous foams with precisely controlled morphology. Our strategy is based on freeze casting, an ice templating materials processing technique that has recently emerged for the structuration of colloids into macroporous materials. Our results indicate that it is possible to combine the precise structuration of the materials with cellular metabolic activity for the model organism Saccharomyces cerevisiae. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Emergent 1d Ising Behavior in AN Elementary Cellular Automaton Model

    Science.gov (United States)

    Kassebaum, Paul G.; Iannacchione, Germano S.

    The fundamental nature of an evolving one-dimensional (1D) Ising model is investigated with an elementary cellular automaton (CA) simulation. The emergent CA simulation employs an ensemble of cells in one spatial dimension, each cell capable of two microstates interacting with simple nearest-neighbor rules and incorporating an external field. The behavior of the CA model provides insight into the dynamics of coupled two-state systems not expressible by exact analytical solutions. For instance, state progression graphs show the causal dynamics of a system through time in relation to the system's entropy. Unique graphical analysis techniques are introduced through difference patterns, diffusion patterns, and state progression graphs of the 1D ensemble visualizing the evolution. All analyses are consistent with the known behavior of the 1D Ising system. The CA simulation and new pattern recognition techniques are scalable (in both dimension, complexity, and size) and have many potential applications such as complex design of materials, control of agent systems, and evolutionary mechanism design.

  12. Reversible one-dimensional cellular automata with one of the two Welch indices equal to 1 and full shifts

    International Nuclear Information System (INIS)

    Mora, Juan Carlos Seck Tuoh; Hernandez, Manuel Gonzalez; Vergara, Sergio V Chapa

    2003-01-01

    Reversible cellular automata are invertible discrete dynamical systems which have been widely studied both for analysing interesting theoretical questions and for obtaining relevant practical applications, for instance, simulating invertible natural systems or implementing data coding devices. An important problem in the theory of reversible automata is to know how the local behaviour which is not invertible is able to yield a reversible global one. In this sense, symbolic dynamics plays an important role for obtaining an adequate representation of a reversible cellular automaton. In this paper we prove the equivalence between a reversible automaton where the ancestors only differ at one side (technically with one of the two Welch indices equal to 1) and a full shift. We represent any reversible automaton by a de Bruijn diagram, and we characterize the way in which the diagram produces an evolution formed by undefined repetitions of two states. By means of amalgamations, we prove that there is always a way of transforming a de Bruijn diagram into the full shift. Finally, we provide an example illustrating the previous results

  13. Reversible one-dimensional cellular automata with one of the two Welch indices equal to 1 and full shifts

    Energy Technology Data Exchange (ETDEWEB)

    Mora, Juan Carlos Seck Tuoh [Centro de Investigacion Avanzada en Ingenieria Industrial, Universidad Autonoma del Estado de Hidalgo, Carr Pachuca-Tulancingo Km 4.5, 42020 Pachuca (Mexico); Hernandez, Manuel Gonzalez [Centro de Investigacion Avanzada en Ingenieria Industrial, Universidad Autonoma del Estado de Hidalgo, Carr Pachuca-Tulancingo Km 4.5, 42020 Pachuca (Mexico); Vergara, Sergio V Chapa [Depto de Ingenieria Electrica, Seccion Computacion, Centro de Investigacion y de Estudios Avanzados, Instituto Politecnico Nacional, Av IPN 2508, Col San Pedro Zacatenco, 07300 DF (Mexico)

    2003-07-25

    Reversible cellular automata are invertible discrete dynamical systems which have been widely studied both for analysing interesting theoretical questions and for obtaining relevant practical applications, for instance, simulating invertible natural systems or implementing data coding devices. An important problem in the theory of reversible automata is to know how the local behaviour which is not invertible is able to yield a reversible global one. In this sense, symbolic dynamics plays an important role for obtaining an adequate representation of a reversible cellular automaton. In this paper we prove the equivalence between a reversible automaton where the ancestors only differ at one side (technically with one of the two Welch indices equal to 1) and a full shift. We represent any reversible automaton by a de Bruijn diagram, and we characterize the way in which the diagram produces an evolution formed by undefined repetitions of two states. By means of amalgamations, we prove that there is always a way of transforming a de Bruijn diagram into the full shift. Finally, we provide an example illustrating the previous results.

  14. Language and other artifacts: socio-cultural dynamics of niche construction

    Science.gov (United States)

    Sinha, Chris

    2015-01-01

    Niche construction theory is a relatively new approach in evolutionary biology that seeks to integrate an ecological dimension into the Darwinian theory of evolution by natural selection. It is regarded by many evolutionary biologists as providing a significant revision of the Neo-Darwinian modern synthesis that unified Darwin’s theory of natural and sexual selection with 20th century population genetics. Niche construction theory has been invoked as a processual mediator of social cognitive evolution and of the emergence and evolution of language. I argue that language itself can be considered as a biocultural niche and evolutionary artifact. I provide both a general analysis of the cognitive and semiotic status of artifacts, and a formal analysis of language as a social and semiotic institution, based upon a distinction between the fundamental semiotic relations of “counting as” and “standing for.” I explore the consequences for theories of language and language learning of viewing language as a biocultural niche. I suggest that not only do niches mediate organism-organism interactions, but also that organisms mediate niche-niche interactions in ways that affect evolutionary processes, with the evolution of human infancy and childhood as a key example. I argue that language as a social and semiotic system is not only grounded in embodied engagements with the material and social-interactional world, but also grounds a sub-class of artifacts of particular significance in the cultural history of human cognition. Symbolic cognitive artifacts materially and semiotically mediate human cognition, and are not merely informational repositories, but co-agentively constitutive of culturally and historically emergent cognitive domains. I provide examples of the constitutive cognitive role of symbolic cognitive artifacts drawn from my research with my colleagues on cultural and linguistic conceptualizations of time, and their cultural variability. I conclude by

  15. Constrained pattern of viral evolution in acute and early HCV infection limits viral plasticity.

    Directory of Open Access Journals (Sweden)

    Katja Pfafferott

    2011-02-01

    Full Text Available Cellular immune responses during acute Hepatitis C virus (HCV and HIV infection are a known correlate of infection outcome. Viral adaptation to these responses via mutation(s within CD8+ T-cell epitopes allows these viruses to subvert host immune control. This study examined HCV evolution in 21 HCV genotype 1-infected subjects to characterise the level of viral adaptation during acute and early HCV infection. Of the total mutations observed 25% were within described CD8+ T-cell epitopes or at viral adaptation sites. Most mutations were maintained into the chronic phase of HCV infection (75%. The lack of reversion of adaptations and high proportion of silent substitutions suggests that HCV has structural and functional limitations that constrain evolution. These results were compared to the pattern of viral evolution observed in 98 subjects during a similar phase in HIV infection from a previous study. In contrast to HCV, evolution during acute HIV infection is marked by high levels of amino acid change relative to silent substitutions, including a higher proportion of adaptations, likely reflecting strong and continued CD8+ T-cell pressure combined with greater plasticity of the virus. Understanding viral escape dynamics for these two viruses is important for effective T cell vaccine design.

  16. Quantifying the global cellular thiol-disulfide status

    DEFF Research Database (Denmark)

    Hansen, Rosa E; Roth, Doris; Winther, Jakob R

    2009-01-01

    It is widely accepted that the redox status of protein thiols is of central importance to protein structure and folding and that glutathione is an important low-molecular-mass redox regulator. However, the total cellular pools of thiols and disulfides and their relative abundance have never been...... determined. In this study, we have assembled a global picture of the cellular thiol-disulfide status in cultured mammalian cells. We have quantified the absolute levels of protein thiols, protein disulfides, and glutathionylated protein (PSSG) in all cellular protein, including membrane proteins. These data...... cell types. However, when cells are exposed to a sublethal dose of the thiol-specific oxidant diamide, PSSG levels increase to >15% of all protein cysteine. Glutathione is typically characterized as the "cellular redox buffer"; nevertheless, our data show that protein thiols represent a larger active...

  17. A three-dimensional cellular automata model coupled with finite element method and thermodynamic database for alloy solidification

    Science.gov (United States)

    Zhao, Y.; Qin, R. S.; Chen, D. F.

    2013-08-01

    A three-dimensional (3D) cellular automata (CA) model has been developed for the simulation of microstructure evolution in alloy solidification. The governing rule for the CA model is associated with the phase transition driving force which is obtained via a thermodynamic database. This determines the migration rate of the non-equilibrium solid-liquid (SL) interface and is calculated according to the local temperature and chemical composition. The curvature of the interface and the anisotropic property of the surface energy are taken into consideration. A 3D finite element (FE) method is applied for the calculation of transient heat and mass transfer. Numerical calculations for the solidification of Fe-1.5 wt% C alloy have been performed. The morphological evolution of dendrites, carbon segregation and temperature distribution in both isothermal and non-isothermal conditions are studied. The parameters affecting the growth of equiaxed and columnar dendrites are discussed. The calculated results are verified using the analytical model and previous experiments. The method provides a sophisticated approach to the solidification of multi-phase and multi-component systems.

  18. Cellular energy allocation in zebra mussels exposed along a pollution gradient: linking cellular effects to higher levels of biological organization

    International Nuclear Information System (INIS)

    Smolders, R.; Bervoets, L.; Coen, W. de; Blust, R.

    2004-01-01

    Organisms exposed to suboptimal environments incur a cost of dealing with stress in terms of metabolic resources. The total amount of energy available for maintenance, growth and reproduction, based on the biochemical analysis of the energy budget, may provide a sensitive measure of stress in an organism. While the concept is clear, linking cellular or biochemical responses to the individual and population or community level remains difficult. The aim of this study was to validate, under field conditions, using cellular energy budgets [i.e. changes in glycogen-, lipid- and protein-content and mitochondrial electron transport system (ETS)] as an ecologically relevant measurement of stress by comparing these responses to physiological and organismal endpoints. Therefore, a 28-day in situ bioassay with zebra mussels (Dreissena polymorpha) was performed in an effluent-dominated stream. Five locations were selected along the pollution gradient and compared with a nearby (reference) site. Cellular Energy Allocation (CEA) served as a biomarker of cellular energetics, while Scope for Growth (SFG) indicated effects on a physiological level and Tissue Condition Index and wet tissue weight/dry tissue weight ratio were used as endpoints of organismal effects. Results indicated that energy budgets at a cellular level of biological organization provided the fastest and most sensitive response and energy budgets are a relevant currency to extrapolate cellular effects to higher levels of biological organization within the exposed mussels. - Exposure of zebra mussels along a pollution gradient has adverse effects on the cellular energy allocation, and results can be linked with higher levels of biological organization

  19. Cellular energy allocation in zebra mussels exposed along a pollution gradient: linking cellular effects to higher levels of biological organization

    Energy Technology Data Exchange (ETDEWEB)

    Smolders, R.; Bervoets, L.; Coen, W. de; Blust, R

    2004-05-01

    Organisms exposed to suboptimal environments incur a cost of dealing with stress in terms of metabolic resources. The total amount of energy available for maintenance, growth and reproduction, based on the biochemical analysis of the energy budget, may provide a sensitive measure of stress in an organism. While the concept is clear, linking cellular or biochemical responses to the individual and population or community level remains difficult. The aim of this study was to validate, under field conditions, using cellular energy budgets [i.e. changes in glycogen-, lipid- and protein-content and mitochondrial electron transport system (ETS)] as an ecologically relevant measurement of stress by comparing these responses to physiological and organismal endpoints. Therefore, a 28-day in situ bioassay with zebra mussels (Dreissena polymorpha) was performed in an effluent-dominated stream. Five locations were selected along the pollution gradient and compared with a nearby (reference) site. Cellular Energy Allocation (CEA) served as a biomarker of cellular energetics, while Scope for Growth (SFG) indicated effects on a physiological level and Tissue Condition Index and wet tissue weight/dry tissue weight ratio were used as endpoints of organismal effects. Results indicated that energy budgets at a cellular level of biological organization provided the fastest and most sensitive response and energy budgets are a relevant currency to extrapolate cellular effects to higher levels of biological organization within the exposed mussels. - Exposure of zebra mussels along a pollution gradient has adverse effects on the cellular energy allocation, and results can be linked with higher levels of biological organization.

  20. Optimizing Cellular Networks Enabled with Renewal Energy via Strategic Learning.

    Science.gov (United States)

    Sohn, Insoo; Liu, Huaping; Ansari, Nirwan

    2015-01-01

    An important issue in the cellular industry is the rising energy cost and carbon footprint due to the rapid expansion of the cellular infrastructure. Greening cellular networks has thus attracted attention. Among the promising green cellular network techniques, the renewable energy-powered cellular network has drawn increasing attention as a critical element towards reducing carbon emissions due to massive energy consumption in the base stations deployed in cellular networks. Game theory is a branch of mathematics that is used to evaluate and optimize systems with multiple players with conflicting objectives and has been successfully used to solve various problems in cellular networks. In this paper, we model the green energy utilization and power consumption optimization problem of a green cellular network as a pilot power selection strategic game and propose a novel distributed algorithm based on a strategic learning method. The simulation results indicate that the proposed algorithm achieves correlated equilibrium of the pilot power selection game, resulting in optimum green energy utilization and power consumption reduction.