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Sample records for cellular darwinian evolution

  1. Darwinian Evolution on a Chip

    OpenAIRE

    Paegel, Brian M.; Joyce, Gerald F.

    2008-01-01

    Author Summary The principles of Darwinian evolution are fundamental to understanding biological organization and have been applied to the development of functional molecules in the test tube. Laboratory evolution is greatly accelerated compared with natural evolution, but it usually requires substantial manipulation by the experimenter. Here we describe a system that relies on computer control and microfluidic chip technology to automate the directed evolution of functional molecules, subjec...

  2. Darwinian Evolution and Fractals

    Science.gov (United States)

    Carr, Paul H.

    2009-05-01

    Did nature's beauty emerge by chance or was it intelligently designed? Richard Dawkins asserts that evolution is blind aimless chance. Michael Behe believes, on the contrary, that the first cell was intelligently designed. The scientific evidence is that nature's creativity arises from the interplay between chance AND design (laws). Darwin's ``Origin of the Species,'' published 150 years ago in 1859, characterized evolution as the interplay between variations (symbolized by dice) and the natural selection law (design). This is evident in recent discoveries in DNA, Madelbrot's Fractal Geometry of Nature, and the success of the genetic design algorithm. Algorithms for generating fractals have the same interplay between randomness and law as evolution. Fractal statistics, which are not completely random, characterize such phenomena such as fluctuations in the stock market, the Nile River, rainfall, and tree rings. As chaos theorist Joseph Ford put it: God plays dice, but the dice are loaded. Thus Darwin, in discovering the evolutionary interplay between variations and natural selection, was throwing God's dice!

  3. 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

  4. Darwinian evolution does not rule out the gaia hypothesis.

    Science.gov (United States)

    Sugimoto, Takeshi

    2002-10-21

    This study explores so-called Darwinian Daisyworlds mathematically rigorously in detail. The original Daisyworld was introduced by Watson & Lovelock (1983) to demonstrate how two species of daisies regulate the global temperature of their planet through competition among these species against the rising solar luminosity, i.e. the Gaia hypothesis. Its variants are Darwinian Daisyworlds in which daisies can adapt themselves to the local temperature. Robertson & Robinson (1998) insist their Darwinian daisies lose the ability for temperature regulation on the basis of their spreadsheet simulations. Lenton & Lovelock (2000) point out that the constraints on adaptation recovers Darwinian daisies' ability of temperature regulation on the basis of their Euler-code simulations. The present study shows there exist the exact and closed-form solutions to these two Daisyworlds. The results contradict the former studies: Robertson and Robinson's daisies do regulate the global temperature even longer than non-adaptive daisies; Lenton and Lovelock's daisies are less adaptive than Robertson and Robinson's daisies because of the constraints on adaptation; the introduction of weak adaptability drives species into a dead end of evolution. Thus, the present results confirm that the Gaia hypothesis and Darwinian evolution can coexist. PMID:12384048

  5. Mathematical Demonstration of Darwinian Theory of Evolution

    OpenAIRE

    Williams, Vernon

    2010-01-01

    Darwin's book, Origin of the Species has been a source of public controversy for more than hundred and fifty years. Court cases and mountains of words have not dispelled this controversy. In this paper, a quantitative approach using simple mathematics shows that the concept of evolution by natural selection using only random choice of variables does work. The procedure applied to the optical equations forming the phenotype of a spider eye produces an eye design modeled after the measurements ...

  6. "Synergistic selection": a Darwinian frame for the evolution of complexity.

    Science.gov (United States)

    Corning, Peter A; Szathmáry, Eörs

    2015-04-21

    Non-Darwinian theories about the emergence and evolution of complexity date back at least to Lamarck, and include those of Herbert Spencer and the "emergent evolution" theorists of the later nineteenth and early twentieth centuries. In recent decades, this approach has mostly been espoused by various practitioners in biophysics and complexity theory. However, there is a Darwinian alternative - in essence, an economic theory of complexity - proposing that synergistic effects of various kinds have played an important causal role in the evolution of complexity, especially in the "major transitions". This theory is called the "synergism hypothesis". We posit that otherwise unattainable functional advantages arising from various cooperative phenomena have been favored over time in a dynamic that the late John Maynard Smith characterized and modeled as "synergistic selection". The term highlights the fact that synergistic "wholes" may become interdependent "units" of selection. We provide some historical perspective on this issue, as well as a brief explication of the underlying theory and the concept of synergistic selection, and we describe two relevant models. PMID:25681798

  7. Introduction to the statistical theory of Darwinian evolution

    OpenAIRE

    Peliti, Luca

    1997-01-01

    These lectures contain a brief description of evolutionary models inspired by the statistical mechanics of disordered systems. After an introduction describing the Darwinian paradigm of evolving populations, the deterministic quasispecies equation is described, and the simplest fitness landscapes are discussed. The effect of finite population size is then considered, from the opposing points of view leading to stochastic escape and to adaptive walks. A synthesis is attempted. Finally the effe...

  8. Book review: Darwinian agriculture: How understanding evolution can improve agriculture by R. Ford Dennison

    Science.gov (United States)

    Agricultural research continually seeks to increase productivity while protecting soil, water and genetic resources. The book Darwinian Agriculture: How Understanding Evolution Can Improve Agriculture, by R. Ford Dennison, delivers a thought-provoking view of how principles of ecology and evolution ...

  9. Beyond directed evolution: Darwinian selection as a tool for synthetic biology

    OpenAIRE

    Porcar, Manuel

    2009-01-01

    Synthetic biology is an engineering approach that seeks to design and construct new biological parts, devices and systems, as well as to re-design existing components. However, rationally designed synthetic circuits may not work as expected due to the context-dependence of biological parts. Darwinian selection, the main mechanism through which evolution works, is a major force in creating biodiversity and may be a powerful tool for synthetic biology. This article reviews selection-based techn...

  10. Three-stage Origin of Life as a Result of Directional Darwinian Evolution

    OpenAIRE

    Novikov, Victor P.

    2012-01-01

    The original hypothesis about Three-stage origin of life (TOL) on the Earth is developed and discussed. The role of the temperature factor in life origin is considered. It is supposed, that three stages of abiogenesis (DNA world, RNA world and the Protein world) consistently followed each other during Darwinian evolution. At the same time, the natural directional selection of the most stable macromolecules and effective catalytic reactions took place. The direction of this selection is relate...

  11. Punctuated equilibrium and positive Darwinian evolution in vesicular stomatitis virus.

    OpenAIRE

    Nichol, S.T.; Rowe, J. E.; Fitch, W M

    1993-01-01

    RNA viruses possess the potential for rapid evolution and serve as excellent models to test evolutionary theory. Molecular phylogenetic analysis of the P gene for a larger number of diverse natural isolates of vesicular stomatitis virus reveals no evidence for a molecular clock but instead shows a stepwise evolutionary pattern unlike that ever seen before. Each step out from the tree's ancestral root to terminal branch tips correlates not with time of virus isolation but with a south-to-north...

  12. A Heritable Recombination System for Synthetic Darwinian Evolution in Yeast

    OpenAIRE

    Romanini, Dante W.; Peralta-Yahya, Pamela; Mondol, Vanessa; Cornish, Virginia W.

    2012-01-01

    Genetic recombination is central to the generation of molecular diversity and enhancement of evolutionary fitness in living systems. Methods such as DNA shuffling that recapitulate this diversity mechanism in vitro are powerful tools for engineering biomolecules with useful new functions by directed evolution. Synthetic biology now brings demand for analogous technologies that enable the controlled recombination of beneficial mutations in living cells. Thus, here we create a Heritable Recombi...

  13. Comparative Structural Models of Similarities and Differences between "Vehicle" and "Target" in Order to Teach Darwinian "Evolution"

    Science.gov (United States)

    Marcelos, Maria Fatima; Nagem, Ronaldo L.

    2010-01-01

    Our objective is to contribute to the teaching of Classical Darwinian "Evolution" by means of a study of analogies and metaphors. Throughout the history of knowledge about "Evolution" and in Science teaching, tree structures have been used an analogs to refer to "Evolution," such as by Darwin in the "Tree of Life" passage contained in "On The…

  14. A Heritable Recombination system for synthetic Darwinian evolution in yeast.

    Science.gov (United States)

    Romanini, Dante W; Peralta-Yahya, Pamela; Mondol, Vanessa; Cornish, Virginia W

    2012-12-21

    Genetic recombination is central to the generation of molecular diversity and enhancement of evolutionary fitness in living systems. Methods such as DNA shuffling that recapitulate this diversity mechanism in vitro are powerful tools for engineering biomolecules with useful new functions by directed evolution. Synthetic biology now brings demand for analogous technologies that enable the controlled recombination of beneficial mutations in living cells. Thus, here we create a Heritable Recombination system centered around a library cassette plasmid that enables inducible mutagenesis via homologous recombination and subsequent combination of beneficial mutations through sexual reproduction in Saccharomyces cerevisiae. Using repair of nonsense codons in auxotrophic markers as a model, Heritable Recombination was optimized to give mutagenesis efficiencies of up to 6% and to allow successive repair of different markers through two cycles of sexual reproduction and recombination. Finally, Heritable Recombination was employed to change the substrate specificity of a biosynthetic enzyme, with beneficial mutations in three different active site loops crossed over three continuous rounds of mutation and selection to cover a total sequence diversity of 10(13). Heritable Recombination, while at an early stage of development, breaks the transformation barrier to library size and can be immediately applied to combinatorial crossing of beneficial mutations for cell engineering, adding important features to the growing arsenal of next generation molecular biology tools for synthetic biology. PMID:23412545

  15. A simple mathematical model of gradual Darwinian evolution: Emergence of a Gaussian trait distribution in adaptation along a fitness gradient

    OpenAIRE

    Biktashev, Vadim N.

    2011-01-01

    We consider a simple mathematical model of gradual Darwinian evolution in continuous time and continuous trait space, due to intraspecific competition for common resource in an asexually reproducing population in constant environment, while far from evolutionary stable equilibrium. The model admits exact analytical solution. In particular, Gaussian distribution of the trait emerges from generic initial conditions.

  16. Identifying the minimum-energy atomic configuration on a lattice: Lamarckian twist on Darwinian evolution

    Science.gov (United States)

    D'Avezac, Mayeul; Zunger, Alex

    2008-08-01

    We examine how the two different mechanisms proposed historically for biological evolution compare for the determination of crystal structures from random initial lattice configurations. The Darwinian theory of evolution contends that the genetic makeup inherited at birth is the one passed on during mating to new offspring, in which case evolution is a product of environmental pressure and chance. In addition to this mechanism, Lamarck surmised that individuals can also pass on traits acquired during their lifetime. Here we show that the minimum-energy configurations of a binary A1-xBx alloy in the full 0≤x≤1 concentration range can be found much faster if the conventional Darwinian genetic progression—mating configurations and letting the lowest-energy (fittest) offspring survive—is allowed to experience Lamarckian-style fitness improvements during its lifetime. Such improvements consist of A↔B transmutations of some atomic sites (not just atomic relaxations) guided by “virtual-atom” energy gradients. This hybrid evolution is shown to provide an efficient solution to a generalized Ising Hamiltonian, illustrated here by finding the ground states of face-centered-cubic Au1-xPdx using a cluster-expansion functional fitted to first-principles total energies. The statistical rate of success of the search strategies and their practical applicability are rigorously documented in terms of average number of evaluations required to find the solution out of 400 independent evolutionary runs with different random seeds. We show that all exact ground states of a 12-atom supercell ( 212 configurations) can be found within 330 total-energy evaluations, whereas a 36-atom supercell ( 236 configurations) requires on average 39000 evaluations. Thus, this problem cannot be currently addressed with confidence using costly energy functionals [e.g., density-functional theory (DFT) based] unless it is limited to ≤20 atoms. The computational cost can be reduced at the

  17. The search for minimum-energy atomic configurations on a lattice: Lamarckian twist on Darwinian Evolution

    Science.gov (United States)

    D'Avezac, Mayeul; Zunger, Alex

    2008-03-01

    We examine how two different mechanisms proposed historically for biological evolution compare for the determination of crystal structures from random initial lattice-configurations. The Darwinian theory of evolution contends that the genetic makeup inherited at birth is the one passed on to offsprings. Lamarck surmised additionally that offspring can inherit acquired traits. In the case of lattice-configurations, such improvements consist in AB transmutations of atomic sites as guided by ``Virtual Atom'' energy-gradients(M. d'Avezac and Alex Zunger, J. Phys.: Cond. Matt. 19, 402201 (2007)). This hybrid evolution is shown to provide an efficient solution to a generalized Ising Hamiltonian, illustrated by finding the ground-states of face-centered cubic Au1-xPdx using a cluster-expansion functional fitted to first-principles total-energies. For example, finding all minimum-energy structures of a 32-atom supercell with 95,% confidence requires evaluating 750, 000 configurations using local improvements only, 150, 000 using a reciprocal-space genetic algorithm only, and 14,000 using the hybrid approach. We consider applying the lamarckian search to further functionals.

  18. Detecting positive darwinian selection in brain-expressed genes during human evolution

    Institute of Scientific and Technical Information of China (English)

    QI XueBin; Alice A. LIN; Luca L. CAVALLI-SFORZA; WANG Jun; SU Bing; YANG Su; ZHENG HongKun; WANG YinQiu; LIAO ChengHong; LIU Ying; CHEN XiaoHua; SHI Hong; YU XiaoJing

    2007-01-01

    To understand the genetic basis that underlies the phenotypic divergence between human and nonhuman primates, we screened a total of 7176 protein-coding genes expressed in the human brain and compared them with the chimpanzee orthologs to identify genes that show evidence of rapid evolution in the human lineage. Our results showed that the nonsynonymous/synonymous substitution (Ka/Ks) ratio for genes expressed in the brain of human and chimpanzee is 0.3854, suggesting that the brain-expressed genes are under functional constraint. The X-linked human brain-expressed genes evolved more rapidly than autosomal ones. We further dissected the molecular evolutionary patterns of 34 candidate genes by sequencing representative primate species to identify lineage-specific adaptive evolution. Fifteen out of the 34 candidate genes showed evidence of positive Darwinian selection in human and/or chimpanzee lineages. These genes are predicted to play diverse functional roles in embryonic development, spermatogenesis and male fertility, signal transduction, sensory nociception, and neural function. This study together with others demonstrated the usefulness and power of phylogenetic comparison of multiple closely related species in detecting lineage-specific adaptive evolution, and the identification of the positively selected brain-expressed genes may add new knowledge to the understanding of molecular mechanism of human origin.

  19. Individuals and groups in evolution: Darwinian pluralism and the multilevel selection debate

    Indian Academy of Sciences (India)

    Telmo Pievani

    2014-04-01

    Outlined here is an updated review of the long-standing `kin selection vs group selection’ debate. Group selection is a highly contentious concept, scientifically and philosophically. In 2012, Dawkins’ attack against Wilson’s latest book about eusociality concentrated all the attention on group selection and its mutual exclusivity with respect to inclusive fitness theory. Both opponents seem to be wrong, facing the general consensus in the field, which favours a pluralistic approach. Historically, despite some misunderstandings in current literature, such a perspective is clearly rooted in Darwin’s writings, which suggested a plurality of levels of selection and a general view that we propose to call `imperfect selfishness’. Today, the mathematically updated hypothesis of group selection has little to do with earlier versions of `group selection’. It does not imply ontologically unmanageable notions of `groups’. We propose here population structure as the main criterion of compatibility between kin selection and group selection. The latter is now evidently a pattern among others within a more general `multilevel selection’ theory. Different explanations and patterns are not mutually exclusive. Such a Darwinian pluralism is not a piece of the past, but a path into the future. A challenge in philosophy of biology will be to figure out the logical structure of this emerging pluralistic theory of evolution in such contentious debates.

  20. The pre-Mendelian, pre-Darwinian world: Shifting relations between genetic and epigenetic mechanisms in early multicellular evolution

    Indian Academy of Sciences (India)

    Stuart A Newman

    2005-02-01

    The reliable dependence of many features of contemporary organisms on changes in gene content and activity is tied to the processes of Mendelian inheritance and Darwinian evolution. With regard to morphological characters, however, Mendelian inheritance is the exception rather than the rule, and neo-Darwinian mechanisms in any case do not account for the origination (as opposed to the inherited variation) of such characters. It is proposed, therefore, that multicellular organisms passed through a pre-Mendelian, pre-Darwinian phase, whereby cells, genes and gene products constituted complex systems with context-dependent, self-organizing morphogenetic capabilities. An example is provided of a plausible ‘core’ mechanism for the development of the vertebrate limb that is both inherently pattern forming and morphogenetically plastic. It is suggested that most complex multicellular structures originated from such systems. The notion that genes are privileged determinants of biological characters can only be sustained by neglecting questions of evolutionary origination and the evolution of developmental mechanisms.

  1. Research program for a search of the origin of Darwinian evolution - Research program for a vesicle-based model of the origin of Darwinian evolution on prebiotic early Earth

    Science.gov (United States)

    Tessera, Marc

    2016-03-01

    The search for origin of `life' is made even more complicated by differing definitions of the subject matter, although a general consensus is that an appropriate definition should center on Darwinian evolution (Cleland and Chyba 2002). Within a physical approach which has been defined as a level-4 evolution (Tessera and Hoelzer 2013), one mechanism could be described showing that only three conditions are required to allow natural selection to apply to populations of different system lineages. This approach leads to a vesicle- based model with the necessary properties. Of course such a model has to be tested. Thus, after a brief presentation of the model an experimental program is proposed that implements the different steps able to show whether this new direction of the research in the field is valid and workable.

  2. Modeling evolution and immune system by cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Bezzi, M. [Scuola Internazionale Superiore di Studi Avanzati, Trieste (Italy); Istituto Nazionale di Fisica della Materia, Florence (Italy)

    2001-07-01

    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.

  3. Modeling evolution and immune system by cellular automata

    International Nuclear Information System (INIS)

    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

  4. If we are all cultural Darwinians what’s the fuss about? Clarifying recent disagreements in the field of cultural evolution

    OpenAIRE

    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 cultural transmission should be considered a preservative mechanism allowing selection among different variants, or a transformative process in which individuals recreate variants each time they are t...

  5. A Scoring Rubric for Students' Responses to Simple Evolution Questions: Darwinian Components

    Science.gov (United States)

    Jensen, Murray; Moore, Randy; Hatch, Jay; Hsu, Leon

    2007-01-01

    The call to teach students Darwin's theory of evolution by natural selection has been made by a variety of professional organizations. In addition to these national organizations, almost every state has science education guidelines calling for the teaching of evolution. Many administrators and policymakers believe that evolution is being taught,…

  6. Darwinian selection leads to Gaia.

    Science.gov (United States)

    Staley, Mark

    2002-09-01

    The Gaia hypothesis, in its strongest form, states that the Earth's atmosphere, oceans, and biota form a tightly coupled system that maintains environmental conditions close to optimal for life. According to Gaia theory, optimal conditions are intrinsic, immutable properties of living organisms. It is assumed that the role of Darwinian selection is to favor organisms that act to stabilize environmental conditions at these optimal levels. In this paper, an alternative form of Gaia theory based on more traditional Darwinian principles is proposed. In the new approach, environmental regulation is a consequence of population dynamics, not Darwinian selection. The role of selection is to favor organisms that are best adapted to prevailing environmental conditions. However, the environment is not a static backdrop for evolution, but is heavily influenced by the presence of living organisms. The resulting co-evolving dynamical process eventually leads to the convergence of equilibrium and optimal conditions. A simple Daisyworld model is used to illustrate this convergence phenomenon. Sensitivity analysis of the Daisyworld model suggests that in stable ecosystems, the convergence of equilibrium and optimal conditions is inevitable, provided there are no externally driven shocks to the system. The end result may appear to be the product of a cooperative venture, but is in fact the outcome of Darwinian selection acting upon "selfish" organisms. PMID:12297068

  7. The evolutionary and non-Darwinian economics of Joseph Schumpeter

    OpenAIRE

    Hodgson, Geoffrey M.

    1997-01-01

    In a recent paper, Matthias Kelm (1997) accepts that `Schumpeter's definition of evolution does not contain any Darwinian mechanism such as natural selection or any other biological concept' and that Schumpeter `made no such attempt' to apply `Darwinian theory to economic evolution'. However, Kelm goes on to argue that Schumpeter would have been a Darwinian if circumstances were different. It is argued here that this contention is highly implausible because Schumpeter explicitly rejected biol...

  8. Quantum Darwinism as a Darwinian process

    CERN Document Server

    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 theory of Quantum Darwinism is discussed from the view that Zurek's derivation of the measurement axioms implies that the evolution of a quantum system entangled with environmental entities is determined solely by the nature of the entangled system. There need be no further logical foundation. Quantum Darwinism is found to conform to the Darwinian paradigm in unexpected detail and is thus may be considered a theory within the framework of Universal Darwinism. With the inclusion of Quantum Darwinism within Universal Darwinism a...

  9. Effects of Darwinian Selection and Mutability on Rate of Broadly Neutralizing Antibody Evolution during HIV-1 Infection.

    Science.gov (United States)

    Sheng, Zizhang; Schramm, Chaim A; Connors, Mark; Morris, Lynn; Mascola, John R; Kwong, Peter D; Shapiro, Lawrence

    2016-05-01

    Accumulation of somatic mutations in antibody variable regions is critical for antibody affinity maturation, with HIV-1 broadly neutralizing antibodies (bnAbs) generally requiring years to develop. We recently found that the rate at which mutations accumulate decreases over time, but the mechanism governing this slowing is unclear. In this study, we investigated whether natural selection and/or mutability of the antibody variable region contributed significantly to observed decrease in rate. We used longitudinally sampled sequences of immunoglobulin transcripts of single lineages from each of 3 donors, as determined by next generation sequencing. We estimated the evolutionary rates of the complementarity determining regions (CDRs), which are most significant for functional selection, and found they evolved about 1.5- to 2- fold faster than the framework regions. We also analyzed the presence of AID hotspots and coldspots at different points in lineage development and observed an average decrease in mutability of less than 10 percent over time. Altogether, the correlation between Darwinian selection strength and evolutionary rate trended toward significance, especially for CDRs, but cannot fully explain the observed changes in evolutionary rate. The mutability modulated by AID hotspots and coldspots changes correlated only weakly with evolutionary rates. The combined effects of Darwinian selection and mutability contribute substantially to, but do not fully explain, evolutionary rate change for HIV-1-targeting bnAb lineages. PMID:27191167

  10. Organization of networks with tagged nodes and biased links: a priori distinct communities. The case of Intelligent Design Proponents and Darwinian Evolution Defenders

    CERN Document Server

    Rotundo, G

    2010-01-01

    Among topics of opinion formation it is of interest to observe the characteristics of networks with a priori distinct communities. As an illustration, we report on the citation network(s) unfolded in the recent decades through web available works belonging to selected members of the Neocreationist and Intelligent Design Proponents (IDP) and the Darwinian Evolution Defenders (DED) communities. An adjacency matrix of tagged nodes is first constructed; it is not symmetric. A generalization of considerations pertaining to the case of networks with biased links, directed or undirected, is thus presented. The main characteristic coefficients describing the structure of such partially directed networks with tagged nodes are outlined. The structural features are discussed searching for statistical aspects, equivalence or not of subnetworks through the degree distributions, each network assortativity, the global and local clustering coefficients and the Average Overlap Indices. The various closed and open triangles ma...

  11. The instinctual nation-state: non-Darwinian theories, state science and ultra-nationalism in Oka Asajirō's Evolution and Human Life.

    Science.gov (United States)

    Sullivan, Gregory

    2011-01-01

    In his anthology of socio-political essays, Evolution and Human Life, Oka Asajirō (1868-1944), early twentieth century Japan's foremost advocate of evolutionism, developed a biological vision of the nation-state as super-organism that reflected the concerns and aims of German-inspired Meiji statism and anticipated aspects of radical ultra-nationalism. Drawing on non-Darwinian doctrines, Oka attempted to realize such a fused or organic state by enhancing social instincts that would bind the minzoku (ethnic nation) and state into a single living entity. Though mobilization during the Russo-Japanese War seemed to evince this super-organism, the increasingly contentious and complex society that emerged in the war's aftermath caused Oka to turn first to Lamarckism and eventually to orthogenesis in the hopes of preserving the instincts needed for a viable nation-state. It is especially in the state interventionist measures that Oka finally came to endorse in order to forestall orthogenetically-driven degeneration that the technocratic proclivities of his statist orientation become most apparent. The article concludes by suggesting that Oka's emphasis on degeneration, autarkic expansion, and, most especially, totalitarian submersion of individuals into the statist collectivity indicates a complex relationship between his evolutionism and fascist ideology, what recent scholarship has dubbed radical Shinto ultra-nationalism. PMID:21080039

  12. A darwinian perspective: right premises, questionable conclusion. A commentary on Niall Shanks and Rebecca Pyles' "Evolution and medicine: the long reach of "Dr. Darwin""

    Directory of Open Access Journals (Sweden)

    Melnick Ronald

    2008-02-01

    Full Text Available Abstract As Dobzhansky wrote, nothing in biology makes sense outside the context of the evolutionary theory, and this truth has not been sufficiently explored yet by medicine. We comment on Shanks and Pyles' recently published paper, Evolution and medicine: the long reach of "Dr. Darwin", and discuss some recent advancements in the application of evolutionary theory to carcinogenesis. However, we disagree with Shanks and Pyles about the usefulness of animal experiments in predicting human hazards. Based on the darwinian observation of inter-species and inter-individual variation in all biological functions, Shanks and Pyles suggest that animal experiments cannot be used to identify hazards to human health. We claim that while the activity of enzymes may vary among individuals and among species, this does not indicate that critical events in disease processes occurring after exposure to hazardous agents differ qualitatively between animal models and humans. In addition, the goal is to avoid human disease whenever possible and with the means that are available at a given point in time. Epidemics of cancer could have been prevented if experimental data had been used to reduce human exposures or ban carcinogenic chemicals. We discuss examples.

  13. Usefulness of a Darwinian system in a biotechnological application: evolution of optical window fluorescent protein variants under selective pressure.

    Directory of Open Access Journals (Sweden)

    Ulrike Schoetz

    Full Text Available With rare exceptions, natural evolution is an extremely slow process. One particularly striking exception in the case of protein evolution is in the natural production of antibodies. Developing B cells activate and diversify their immunoglobulin (Ig genes by recombination, gene conversion (GC and somatic hypermutation (SHM. Iterative cycles of hypermutation and selection continue until antibodies of high antigen binding specificity emerge (affinity maturation. The avian B cell line DT40, a cell line which is highly amenable to genetic manipulation and exhibits a high rate of targeted integration, utilizes both GC and SHM. Targeting the DT40's diversification machinery onto transgenes of interest inserted into the Ig loci and coupling selective pressure based on the desired outcome mimics evolution. Here we further demonstrate the usefulness of this platform technology by selectively pressuring a large shift in the spectral properties of the fluorescent protein eqFP615 into the highly stable and advanced optical imaging expediting fluorescent protein Amrose. The method is advantageous as it is time and cost effective and no prior knowledge of the outcome protein's structure is necessary. Amrose was evolved to have high excitation at 633 nm and excitation/emission into the far-red, which is optimal for whole-body and deep tissue imaging as we demonstrate in the zebrafish and mouse model.

  14. EVOLUTION COMPLEXITY OF THEELEMENTARY CELLULAR AUTOMATON OF RULE 22

    Institute of Scientific and Technical Information of China (English)

    WangYi; JiangZhisong

    2002-01-01

    Cellular automata are the discrete dynamical systems of simple construction but with complex and varied behaviors. In this paper, the elementary cellular automaton of rule 22 is studied by the tools of formal language theory and symbolic dynamics. Its temporal evolution orbits are coarse-grained into evolution sequences and the evolution languages are defined. It is proved that for every n≥2 its width n evolution language is not regular.

  15. The Mystery of the Routine. The Darwinian Destiny of An Evolutionary Theory of Economic Change

    OpenAIRE

    Geoffrey M. Hodgson

    2003-01-01

    The three core Darwinian principles of variety, inheritance and selection are found in Nelson and Winter’s Evolutionary Theory of Economic Change (1982). Is the application of these core Darwinian principles purely analogical, or does it also relate to ontological communalities between social and biological evolution? Why do Nelson and Winter describe their theory as “Lamarckian” despite this strong Darwinian content? This “Lamarckian” inclination is related to their imperfect and inconsisten...

  16. 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

  17. Positive Darwinian selection in human population: A review

    Institute of Scientific and Technical Information of China (English)

    WU DongDong; ZHANG YaPing

    2008-01-01

    This paper reviews a large number of genes under positive Darwinian selection in modern human populations, such as brain development genes, immunity genes, reproductive related genes, percep-tion receptors. The research on the evolutionary property of these genes will provide important insight into human evolution and disease mechanisms. With the increase of population genetics and com-parative genomics data, more and more evidences indicate that positive Darwinian selection plays an indispensable role in the origin and evolution of human beings. This paper will also summarize the methods to detect positive selection, analyze the interference factors faced and make suggestions for further research on positive selection.

  18. Darwinian Model Building

    International Nuclear Information System (INIS)

    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.

  19. Darwinian Model Building

    Science.gov (United States)

    Kester, Do; Bontekoe, Romke

    2011-03-01

    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.

  20. 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...

  1. The Origins of Cellular Life

    OpenAIRE

    Schrum, Jason P.; Zhu, Ting F.; SZOSTAK, JACK W.

    2010-01-01

    Understanding the origin of cellular life on Earth requires the discovery of plausible pathways for the transition from complex prebiotic chemistry to simple biology, defined as the emergence of chemical assemblies capable of Darwinian evolution. We have proposed that a simple primitive cell, or protocell, would consist of two key components: a protocell membrane that defines a spatially localized compartment, and an informational polymer that allows for the replication and inheritance of fun...

  2. Numerical investigation on evolution of cylindrical cellular detonation

    Institute of Scientific and Technical Information of China (English)

    WANG Chun; JIANG Zong-lin; HU Zong-min; HAN Gui-lai

    2008-01-01

    Cylindrical cellular detonation is numerically investigated by solving twodimensional reactive Euler equations with a finite volume method on a two-dimensional self-adaptive unstructured mesh.The one-step reversible chemical reaction model is applied to simplify the control parameters of chemical reaction.Numerical results demonstrate the evolution of cellular cell splitting of cylindrical cellular detonation explored in experimentas.Split of cellular structures shows different features in the near-field and far-field from the initiation zone.Variation of the local curvature is a key factor in the behavior of cell split of cylindrical cellular detonation in propagation.Numerical results show that split of cellular structures comes from the self-organization of transverse waves corresponding to the development of small disturbances along the detonation front related to detonation instability.

  3. 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…

  4. The Malthusian-Darwinian dynamic and the trajectory of civilization

    Science.gov (United States)

    Nekola, Jeffrey C.; Allen, Craig D.; Brown, James H.; Burger, Joseph R.; Davidson, Ana D.; Fristoe, Trevor S.; Hamilton, Marcus J.; Hammond, Sean T.; Kodric-Brown, Astrid; Mercado-Silva, Norman; Okie, Jordan G.

    2013-01-01

    Two interacting forces influence all populations: the Malthusian dynamic of exponential growth until resource limits are reached, and the Darwinian dynamic of innovation and adaptation to circumvent these limits through biological and/or cultural evolution. The specific manifestations of these forces in modern human society provide an important context for determining how humans can establish a sustainable relationship with the finite Earth.

  5. Autocatalytic closure and the evolution of cellular information processing networks

    OpenAIRE

    Decraene, James

    2009-01-01

    Cellular Information Processing Networks (CIPNs) are chemical networks of interacting molecules occurring in living cells. Through complex molecular interactions, CIPNs are able to coordinate critical cellular activities in response to internal and external stimuli. We hypothesise that CIPNs may be abstractly regarded as subsets of collectively autocatalytic (i.e., organisationally closed) reaction networks. These closure properties would subsequently interact with the evolution and adaptatio...

  6. The search for purpose in a post-Darwinian universe: George Bernard Shaw, 'creative evolution', and Shavian eugenics: 'The dark side of the force'.

    Science.gov (United States)

    Hale, Piers J

    2006-01-01

    The Irish playwright and socialist George Bernard Shaw has been of marginal concern for historians of biology because his vitalist Lamarckism has been viewed as out of step with contemporary science. However, Julian Huxley and J.B.S. Haldane were certainly of the opinion that Shaw was a man of influence in this regard and took pains to counter his views in their own attempts to engage the public in science. Previously, Shaw's colleague and friend H.G. Wells had also agued with Shaw from his own mechanistic neo-Darwinian perspective. The very public debate between Shaw and Wells, which continued to concern Huxley and Haldane, shows that public concern over the moral implications of Darwinism has a long history. Taking into account the opinions of John Maynard Smith on this matter, I suggest that a consideration of Shaw in this context can give us an understanding of the historical popularity of vitalist teleology as well as of the persistent ambivalence to the non-normative character of Darwinism. PMID:17702503

  7. 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

    OpenAIRE

    GERMÁN MANRÍQUEZ

    2010-01-01

    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 p...

  8. Emergence of Thermodynamics from Darwinian Dynamics

    OpenAIRE

    Ao, P.

    2007-01-01

    Darwinian dynamics is manifestly stochastic and nonconservative, but has a profound connection to conservative dynamics in physics. In the present paper the main ideas and logical steps leading to thermodynamics from Darwinian dynamics are discussed in a quantitative manner. A synthesis between nonequilibrum dynamics and conservative dynamics is outlined.

  9. Millimeter-Wave Evolution for 5G Cellular Networks

    Science.gov (United States)

    Sakaguchi, Kei; Tran, Gia Khanh; Shimodaira, Hidekazu; Nanba, Shinobu; Sakurai, Toshiaki; Takinami, Koji; Siaud, Isabelle; Strinati, Emilio Calvanese; Capone, Antonio; Karls, Ingolf; Arefi, Reza; Haustein, Thomas

    Triggered by the explosion of mobile traffic, 5G (5th Generation) cellular network requires evolution to increase the system rate 1000 times higher than the current systems in 10 years. Motivated by this common problem, there are several studies to integrate mm-wave access into current cellular networks as multi-band heterogeneous networks to exploit the ultra-wideband aspect of the mm-wave band. The authors of this paper have proposed comprehensive architecture of cellular networks with mm-wave access, where mm-wave small cell basestations and a conventional macro basestation are connected to Centralized-RAN (C-RAN) to effectively operate the system by enabling power efficient seamless handover as well as centralized resource control including dynamic cell structuring to match the limited coverage of mm-wave access with high traffic user locations via user-plane/control-plane splitting. In this paper, to prove the effectiveness of the proposed 5G cellular networks with mm-wave access, system level simulation is conducted by introducing an expected future traffic model, a measurement based mm-wave propagation model, and a centralized cell association algorithm by exploiting the C-RAN architecture. The numerical results show the effectiveness of the proposed network to realize 1000 times higher system rate than the current network in 10 years which is not achieved by the small cells using commonly considered 3.5 GHz band. Furthermore, the paper also gives latest status of mm-wave devices and regulations to show the feasibility of using mm-wave in the 5G systems.

  10. Molecular chaperones: The modular evolution of cellular networks

    Indian Academy of Sciences (India)

    Tamás Korcsmáros; István A Kovács; Máté S Szalay; Péter Csermely

    2007-04-01

    Molecular chaperones play a prominent role in signaling and transcriptional regulatory networks of the cell. Recent advances uncovered that chaperones act as genetic buffers stabilizing the phenotype of various cells and organisms and may serve as potential regulators of evolvability. Chaperones have weak links, connect hubs, are in the overlaps of network modules and may uncouple these modules during stress, which gives an additional protection for the cell at the network-level. Moreover, after stress chaperones are essential to re-build inter-modular contacts by their low affinity sampling of the potential interaction partners in different modules. This opens the way to the chaperone-regulated modular evolution of cellular networks, and helps us to design novel therapeutic and anti-aging strategies.

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

    OpenAIRE

    Karafyllidis, Ioannis G.

    2008-01-01

    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 define...

  12. Teaching Darwinian Evolution: Learning from Religious Education

    Science.gov (United States)

    Stolberg, Tonie L.

    2010-01-01

    This article examines what science education might be able to learn from phenomenological religious education's attempts to teach classes where students hold a plurality of religious beliefs. Recent statements as to how best to accomplish the central pedagogical concept of "learning from religion" as a vehicle for human transformation are…

  13. Darwinian Evolution of Prions in Cell Culture*

    OpenAIRE

    Li, Jiali; Browning, Shawn; Mahal, Sukhvir P.; Oelschlegel, Anja M.; Weissmann, Charles

    2009-01-01

    Prions are infectious proteins consisting mainly of PrPSc, a β sheet-rich conformer of the normal host protein PrPC, and occur in different strains. Strain identity is thought to be encoded by PrPSc conformation. We found that biologically cloned prion populations gradually became heterogeneous by accumulating “mutants”, and selective pressures resulted in the emergence of different mutants as major constituents of the evolving population. Thus, when transferred from brain to cultured cells, ...

  14. 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

  15. Eukaryotic protein domains as functional units of cellular evolution

    DEFF Research Database (Denmark)

    Jin, Jing; Xie, Xueying; Chen, Chen;

    2009-01-01

    of different domain types to assess the molecular compartment occupied by each domain. This reveals that specific subsets of domains demarcate particular cellular processes, such as growth factor signaling, chromatin remodeling, apoptotic and inflammatory responses, or vesicular trafficking. We suggest...

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

    Science.gov (United States)

    Russell Hunter, T.

    2012-07-01

    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 selection had not presented any new scientific or theological difficulties for traditional Christian belief. From his personal correspondence with the author of the Origin, Gray well knew that Darwin did not affirm God's "particular" design of nature but conceded to the possibility that evolution proceeded according to "designed laws." From this concession, Gray attempted to develop a post-Darwinian natural theology which encouraged theistic naturalists to view God's design of nature through the evolutionary process in a manner similar to the way in which they viewed God's Providential interaction with human history. Indeed, securing a fair reading of the Origin was not Gray's sole aim as a promoter of Darwinian ideas. In Darwin's theory of natural selection, Gray believed he had discovered the means by which a more robust natural theological conception of the living and evolving natural world could be developed. In this paper I outline Gray's efforts to produce and popularize a theistic interpretation of Darwinian theory in order to correct various misconceptions concerning Gray's natural theological views and their role in the Darwinian Revolution.

  17. Multiple cellular origins and molecular evolution of intrahepatic cholangiocarcinoma.

    Science.gov (United States)

    Wei, Miaoyan; Lü, Lisheng; Lin, Peiyi; Chen, Zhisheng; Quan, Zhiwei; Tang, Zhaohui

    2016-09-01

    Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy associated with unfavorable prognosis and for which no effective treatments are available. Its molecular pathogenesis is poorly understood. Genome-wide sequencing and high-throughput technologies have provided critical insights into the molecular basis of ICC while sparking a heated debate on the cellular origin. Cancer exhibits variabilities in origin, progression and cell biology. Recent evidence suggests that ICC has multiple cellular origins, including differentiated hepatocytes; intrahepatic biliary epithelial cells (IBECs)/cholangiocytes; pluripotent stem cells, such as hepatic stem/progenitor cells (HPCs) and biliary tree stem/progenitor cells (BTSCs); and peribiliary gland (PBG). However, both somatic mutagenesis and epigenomic features are highly cell type-specific. Multiple cellular origins may have profoundly different genomic landscapes and key signaling pathways, driving phenotypic variation and thereby posing significant challenges to personalized medicine in terms of achieving the optimal drug response and patient outcome. Considering this information, we have summarized the latest experimental evidence and relevant literature to provide an up-to-date view of the cellular origin of ICC, which will contribute to establishment of a hierarchical model of carcinogenesis and allow for improvement of the anatomical-based classification of ICC. These new insights have important implications for both the diagnosis and treatment of ICC patients. PMID:26940139

  18. Evolution of Cellular Automata using Lindenmayer Systems and Fourier Transforms

    OpenAIRE

    Berg, Sivert

    2013-01-01

    Cellular automata (CAs) are a class of highly parallel computing systems consisting of many simple computing elements called cells. The cells can only communicate with neighboring cells, meaning there is no global communication in the system. Programming such a system to solve complex problems can be a daunting task, and indirect methods are often applied to make it easier. In this thesis we use evolutionary algorithms (EAs) to evolve CAs. We also look at the possibility of employing L-system...

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

    Directory of Open Access Journals (Sweden)

    Emiko Furusato

    2010-03-01

    Full Text Available 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. Evolution of cellular morpho-phenotypes in cancer metastasis.

    Science.gov (United States)

    Wu, Pei-Hsun; Phillip, Jude M; Khatau, Shyam B; Chen, Wei-Chiang; Stirman, Jeffrey; Rosseel, Sophie; Tschudi, Katherine; Van Patten, Joshua; Wong, Michael; Gupta, Sonal; Baras, Alexander S; Leek, Jeffrey T; Maitra, Anirban; Wirtz, Denis

    2015-01-01

    Intratumoral heterogeneity greatly complicates the study of molecular mechanisms driving cancer progression and our ability to predict patient outcomes. Here we have developed an automated high-throughput cell-imaging platform (htCIP) that allows us to extract high-content information about individual cells, including cell morphology, molecular content and local cell density at single-cell resolution. We further develop a comprehensive visually-aided morpho-phenotyping recognition (VAMPIRE) tool to analyze irregular cellular and nuclear shapes in both 2D and 3D microenvironments. VAMPIRE analysis of ~39,000 cells from 13 previously sequenced patient-derived pancreatic cancer samples indicate that metastasized cells present significantly lower heterogeneity than primary tumor cells. We found the same morphological signature for metastasis for a cohort of 10 breast cancer cell lines. We further decipher the relative contributions to heterogeneity from cell cycle, cell-cell contact, cell stochasticity and heritable morphological variations. PMID:26675084

  1. Sub-classes and evolution stability of Wolfram's classesin the total-rule cellular automata

    Institute of Scientific and Technical Information of China (English)

    YAN Guangwu; TIAN Feng; DONG Yinfeng

    2004-01-01

    In this paper, we propose a concept of sub-classes and its evolution stability for the Wolfram's classes. Firstly, we obtain the sub-classes of the Wolfram's class IV, gene-piece of these sub-classes and their existing circumstance. Secondly, we introduce a new concept, the evolution stability, for the Wolfram's classes and sub-classes of Wolfram's class IV. Lastly, we find that Wolfram's classes I, II, and III have the evolution stability, but sub-classes of the Wolfram's class IV have not the evolution stability for the total rule cellular automata.

  2. How Darwinian models inform therapeutic failure initiated by clonal heterogeneity in cancer medicine

    OpenAIRE

    Gerlinger, M; Swanton, C.

    2010-01-01

    Carcinogenesis is an evolutionary process that establishes the ‘hallmarks of cancer' by natural selection of cell clones that have acquired advantageous heritable characteristics. Evolutionary adaptation has also been proposed as a mechanism that promotes drug resistance during systemic cancer therapy. This review summarises the evidence for the evolution of resistance to cytotoxic and targeted anti-cancer drugs according to Darwinian models and highlights the roles of genomic instability and...

  3. Socio-technical dynamics and political institutions: A multilevel Darwinian framework of sustainability transitions

    OpenAIRE

    G. Marletto

    2014-01-01

    The study of sustainability transitions (SUSTRANs) is an emerging research field that provides useful keys to understand how more sustainable ways to meet societal needs may emerge and develop. As stressed by some scholars, much more work is needed to make political institutions endogenous to SUSTRANs. This paper contributes to such a research endeavour by providing a simple conceptual framework based on multiple levels of Darwinian evolution. The evolutionary environment is defined by a soci...

  4. 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. PMID:21300318

  5. Chemical evolution and life

    OpenAIRE

    Malaterre Christophe

    2015-01-01

    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 na...

  6. Quantum field as a quantum cellular automaton: The Dirac free evolution in one dimension

    International Nuclear Information System (INIS)

    We present a quantum cellular automaton model in one space-dimension which has the Dirac equation as emergent. This model, a discrete-time and causal unitary evolution of a lattice of quantum systems, is derived from the assumptions of homogeneity, parity and time-reversal invariance. The comparison between the automaton and the Dirac evolutions is rigorously set as a discrimination problem between unitary channels. We derive an exact lower bound for the probability of error in the discrimination as an explicit function of the mass, the number and the momentum of the particles, and the duration of the evolution. Computing this bound with experimentally achievable values, we see that in that regime the QCA model cannot be discriminated from the usual Dirac evolution. Finally, we show that the evolution of one-particle states with narrow-band in momentum can be efficiently simulated by a dispersive differential equation for any regime. This analysis allows for a comparison with the dynamics of wave-packets as it is described by the usual Dirac equation. This paper is a first step in exploring the idea that quantum field theory could be grounded on a more fundamental quantum cellular automaton model and that physical dynamics could emerge from quantum information processing. In this framework, the discretization is a central ingredient and not only a tool for performing non-perturbative calculation as in lattice gauge theory. The automaton model, endowed with a precise notion of local observables and a full probabilistic interpretation, could lead to a coherent unification of a hypothetical discrete Planck scale with the usual Fermi scale of high-energy physics. - Highlights: • The free Dirac field in one space dimension as a quantum cellular automaton. • Large scale limit of the automaton and the emergence of the Dirac equation. • Dispersive differential equation for the evolution of smooth states on the automaton. • Optimal discrimination between the

  7. EVOLUTION OF WIRELESS MOBILE COMMUNICATION NETWORKS AND FUTURE OF CELLULAR MARKET IN INDIA

    Directory of Open Access Journals (Sweden)

    Arjun Kondur

    2012-10-01

    Full Text Available In this paper, we discuss the evolution of the mobile communication systems from GSM to LTE (2G to 4G and the trends in the mobile communication industry. The Global System for Mobile Communication (GSM is a well established cellular system targeted here due to its engineering success and the large number of users currently using the services. The flexibility of wireless networks over voice and data transmission makes it one of the most popular modes of communication. Evolution to next generation services depends on an addition of new services and new features to the existing networks or even an integration of different communication technologies. With the invention of the devices such as tablets and smart phones the need to improve the data transmission rates and transmission efficiency has increased to higher than ever before. In this paper, we focus at some of the important issues pertaining to the evolution of mobile communication networks and predict the future of the networks based on the analysis of the cellular market in India. Since GSM networks accounts for more than 75% of the world wide cellular network, only the evolution of GSM network has been discussed in this paper.

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

    International Nuclear Information System (INIS)

    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

  9. Elements for the Development of a Darwinian Scheme Leading to Quantum Mechanics

    Science.gov (United States)

    Baladrón, Carlos

    2015-10-01

    A subquantum theory is examined in which a fundamental system has been characterized as the association of a particle with a continuous trajectory in real space and a classical probabilistic Turing machine defined on an informational space. The particle transfers information to the machine, and this steers the particle by means of self-interaction. In a certain sense, the associated Turing machine might be considered a generalization of the pilot wave function of Bohmian mechanics. The data processing capability entailed by the Turing machine makes the particle a generalized Darwinian system on which natural selection may operate. Darwinian evolution acting on the informational space should then drive the particle from random behaviour purportedly associated to an initial blank state to a possible evolutionarily stable strategy (ESS). Three regulating principles that plausibly encode an ESS are stated. The derivation of the postulates of quantum mechanics is discussed assuming that the behaviour of systems is governed by the three regulating principles. The theory also enables, within the generalized Darwinian framework, a natural characterization of entanglement through the local interaction between the Turing machines of the subsystems. Some possible future experimental and computational tests of the theory are outlined. The central aim of this scheme is to explore the possibility that generalized Darwinian natural selection might induce the emergence of quantum mechanics and its weird features from a real and local underlying description of particles supplemented with a Turing machine on an informational space, since those systems presenting quantum behaviour seem to be the most robust at a microscopic level.

  10. 2D cellular automaton model for the evolution of active region coronal plasmas

    CERN Document Server

    Fuentes, Marcelo López

    2016-01-01

    We study a 2D 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 (EBTEL) model to compute the response of the plasma to the heating events. Using the known response of the XRT 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 t...

  11. Embedding reach-scale fluvial dynamics within the CAESAR cellular automaton landscape evolution model

    Science.gov (United States)

    Van De Wiel, Marco J.; Coulthard, Tom J.; Macklin, Mark G.; Lewin, John

    2007-10-01

    We introduce a new computational model designed to simulate and investigate reach-scale alluvial dynamics within a landscape evolution model. The model is based on the cellular automaton concept, whereby the continued iteration of a series of local process 'rules' governs the behaviour of the entire system. The model is a modified version of the CAESAR landscape evolution model, which applies a suite of physically based rules to simulate the entrainment, transport and deposition of sediments. The CAESAR model has been altered to improve the representation of hydraulic and geomorphic processes in an alluvial environment. In-channel and overbank flow, sediment entrainment and deposition, suspended load and bed load transport, lateral erosion and bank failure have all been represented as local cellular automaton rules. Although these rules are relatively simple and straightforward, their combined and repeatedly iterated effect is such that complex, non-linear geomorphological response can be simulated within the model. Examples of such larger-scale, emergent responses include channel incision and aggradation, terrace formation, channel migration and river meandering, formation of meander cutoffs, and transitions between braided and single-thread channel patterns. In the current study, the model is illustrated on a reach of the River Teifi, near Lampeter, Wales, UK.

  12. The evolution of early cellular systems viewed through the lens of biological interactions

    Directory of Open Access Journals (Sweden)

    Anthony M Poole

    2015-10-01

    Full Text Available The minimal cell concept represents a pragmatic approach to the question of how few genes are required to run a cell. This is a helpful way to build a parts-list, and has been more successful than attempts to deduce a minimal gene set for life by inferring the gene repertoire of the Last Universal Common Ancestor, as few genes trace back to this hypothetical ancestral state. However, the study of minimal cellular systems is the study of biological outliers where, by practical necessity, coevolutionary interactions are minimised or ignored. In this paper, we consider the biological context from which minimal genomes have been removed. For instance, some of the most reduced genomes are from endosymbionts and are the result of coevolutionary interactions with a host; few such organisms are ‘free-living’. As few, if any, biological systems exist in complete isolation, we expect that, as with modern life, early biological systems were part of an ecosystem, replete with organismal interactions. We favour refocusing discussions of the evolution of cellular systems on processes rather than gene counts. We therefore draw a distinction between a pragmatic minimal cell (an interesting engineering problem, a distributed genome (a system resulting from an evolutionary transition involving more than one cell and the looser coevolutionary interactions that are ubiquitous in ecosystems. Finally, we consider the distributed genome and coevolutionary interactions between genomic entities in the context of early evolution.

  13. Gorilla and orangutan brains conform to the primate cellular scaling rules: implications for human evolution.

    Science.gov (United States)

    Herculano-Houzel, Suzana; Kaas, Jon H

    2011-01-01

    Gorillas and orangutans are primates at least as large as humans, but their brains amount to about one third of the size of the human brain. This discrepancy has been used as evidence that the human brain is about 3 times larger than it should be for a primate species of its body size. In contrast to the view that the human brain is special in its size, we have suggested that it is the great apes that might have evolved bodies that are unusually large, on the basis of our recent finding that the cellular composition of the human brain matches that expected for a primate brain of its size, making the human brain a linearly scaled-up primate brain in its number of cells. To investigate whether the brain of great apes also conforms to the primate cellular scaling rules identified previously, we determine the numbers of neuronal and other cells that compose the orangutan and gorilla cerebella, use these numbers to calculate the size of the brain and of the cerebral cortex expected for these species, and show that these match the sizes described in the literature. Our results suggest that the brains of great apes also scale linearly in their numbers of neurons like other primate brains, including humans. The conformity of great apes and humans to the linear cellular scaling rules that apply to other primates that diverged earlier in primate evolution indicates that prehistoric Homo species as well as other hominins must have had brains that conformed to the same scaling rules, irrespective of their body size. We then used those scaling rules and published estimated brain volumes for various hominin species to predict the numbers of neurons that composed their brains. We predict that Homo heidelbergensis and Homo neanderthalensis had brains with approximately 80 billion neurons, within the range of variation found in modern Homo sapiens. We propose that while the cellular scaling rules that apply to the primate brain have remained stable in hominin evolution (since they

  14. 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.

  15. 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

  16. 22号初等元胞自动机的演化复杂性%EVOLUTION COMPLEXITY OF THE ELEMENTARY CELLULAR AUTOMATON OF RULE 22

    Institute of Scientific and Technical Information of China (English)

    王益; 江志松

    2002-01-01

    Cellular automata are the discrete dynamical systems of simple construction but with complex and varied behaviors.In this paper,the elementary cellular automaton of rule 22 is studied by the tools of formal language theory and symbolic dynamics.Its temporal evolution orbits are coarse-grained into evolution sequences and the evolution languages are defined.It is proved that for every n≥2 its width n-evolution language is not regular.

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

    NARCIS (Netherlands)

    Almendro, Vanessa; Cheng, Yu-Kang; Randles, Amanda; Itzkovitz, Shalev; Marusyk, Andriy; Ametller, Elisabet; Gonzalez-Farre, Xavier; Muñoz, Montse; Russnes, Hege G; Helland, Aslaug; 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-

  18. BioJazz: in silico evolution of cellular networks with unbounded complexity using rule-based modeling.

    Science.gov (United States)

    Feng, Song; Ollivier, Julien F; Swain, Peter S; Soyer, Orkun S

    2015-10-30

    Systems biologists aim to decipher the structure and dynamics of signaling and regulatory networks underpinning cellular responses; synthetic biologists can use this insight to alter existing networks or engineer de novo ones. Both tasks will benefit from an understanding of which structural and dynamic features of networks can emerge from evolutionary processes, through which intermediary steps these arise, and whether they embody general design principles. As natural evolution at the level of network dynamics is difficult to study, in silico evolution of network models can provide important insights. However, current tools used for in silico evolution of network dynamics are limited to ad hoc computer simulations and models. Here we introduce BioJazz, an extendable, user-friendly tool for simulating the evolution of dynamic biochemical networks. Unlike previous tools for in silico evolution, BioJazz allows for the evolution of cellular networks with unbounded complexity by combining rule-based modeling with an encoding of networks that is akin to a genome. We show that BioJazz can be used to implement biologically realistic selective pressures and allows exploration of the space of network architectures and dynamics that implement prescribed physiological functions. BioJazz is provided as an open-source tool to facilitate its further development and use. Source code and user manuals are available at: http://oss-lab.github.io/biojazz and http://osslab.lifesci.warwick.ac.uk/BioJazz.aspx. PMID:26101250

  19. 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.

  20. The consuming instinct. What Darwinian consumption reveals about human nature.

    Science.gov (United States)

    Saad, Gad

    2013-01-01

    Editor's note: In this engaging talk given last February on a particularly cold and blustery day at Texas Tech University, Professor Gad Saad of Concordia University discusses his work in the area of evolutionary consumption. In making the case for understanding consumerism from a Darwinian perspective, Saad addresses several key tenets from his books The Consuming Instinct (1) and The Evolutionary Bases of Consumption. (2) In particular, Saad argues that: (1) many consumption acts can be mapped onto four key Darwinian modules (survival, mating, kin selection, and reciprocal altruism); and, (2) cultural products such as song lyrics and movie plotlines are fossils of the human mind that highlight a shared, biologically based human nature. In this wide-ranging inquiry, Saad summarizes several of his other empirical works, including the effects of conspicuous consumption on men's testosterone levels (3) and how the ovulatory cycle in the human female influences consumption. (4) Overall, Professor Saad contends that an infusion of evolutionary and biologically based perspectives into the discipline of consumer behavior and related government regulatory policies yields myriad benefits, notably greater consilience, more effective practices, an ethos of interdisciplinarity, and methodological pluralism. PMID:24047091

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

    International Nuclear Information System (INIS)

    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

  2. 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. PMID:25901860

  3. Evolution of behavioural and cellular defences against parasitoid wasps in the Drosophila melanogaster subgroup.

    Science.gov (United States)

    Lynch, Z R; Schlenke, T A; de Roode, J C

    2016-05-01

    It may be intuitive to predict that host immune systems will evolve to counter a broad range of potential challenges through simultaneous investment in multiple defences. However, this would require diversion of resources from other traits, such as growth, survival and fecundity. Therefore, ecological immunology theory predicts that hosts will specialize in only a subset of possible defences. We tested this hypothesis through a comparative study of a cellular immune response and a putative behavioural defence used by eight fruit fly species against two parasitoid wasp species (one generalist and one specialist). Fly larvae can survive infection by melanotically encapsulating wasp eggs, and female flies can potentially reduce infection rates in their offspring by laying fewer eggs when wasps are present. The strengths of both defences varied significantly but were not negatively correlated across our chosen host species; thus, we found no evidence for a trade-off between behavioural and cellular immunity. Instead, cellular defences were significantly weaker against the generalist wasp, whereas behavioural defences were similar in strength against both wasps and positively correlated between wasps. We investigated the adaptive significance of wasp-induced oviposition reduction behaviour by testing whether wasp-exposed parents produce offspring with stronger cellular defences, but we found no support for this hypothesis. We further investigated the sensory basis of this behaviour by testing mutants deficient in either vision or olfaction, both of which failed to reduce their oviposition rates in the presence of wasps, suggesting that both senses are necessary for detecting and responding to wasps. PMID:26859227

  4. Evolution of secondary cellular circulation flow above submarine bedforms imaged by remote sensing techniques

    OpenAIRE

    Hennings, Ingo; Herbers, Dagmar

    2013-01-01

    Normalized radar cross section (NRCS) modulation and acoustic Doppler current profiler (ADCP) measurements above submarine sand ribbons and sand waves are presented. The two study areas are located in the Southern Bight of the North Sea at the Birkenfels wreck and in the sand wave field of the Lister Tief in the German Bight of the North Sea. These measurements reveal the developments of secondary cellular circulations in tidally induced coastal sea areas. Secondary circulation cells can deve...

  5. Temporal order of evolution of DNA replication systems inferred by comparison of cellular and viral DNA polymerases

    Directory of Open Access Journals (Sweden)

    Koonin Eugene V

    2006-12-01

    Full Text Available Abstract Background The core enzymes of the DNA replication systems show striking diversity among cellular life forms and more so among viruses. In particular, and counter-intuitively, given the central role of DNA in all cells and the mechanistic uniformity of replication, the core enzymes of the replication systems of bacteria and archaea (as well as eukaryotes are unrelated or extremely distantly related. Viruses and plasmids, in addition, possess at least two unique DNA replication systems, namely, the protein-primed and rolling circle modalities of replication. This unexpected diversity makes the origin and evolution of DNA replication systems a particularly challenging and intriguing problem in evolutionary biology. Results I propose a specific succession for the emergence of different DNA replication systems, drawing argument from the differences in their representation among viruses and other selfish replicating elements. In a striking pattern, the DNA replication systems of viruses infecting bacteria and eukaryotes are dominated by the archaeal-type B-family DNA polymerase (PolB whereas the bacterial replicative DNA polymerase (PolC is present only in a handful of bacteriophage genomes. There is no apparent mechanistic impediment to the involvement of the bacterial-type replication machinery in viral DNA replication. Therefore, I hypothesize that the observed, markedly unequal distribution of the replicative DNA polymerases among the known cellular and viral replication systems has a historical explanation. I propose that, among the two types of DNA replication machineries that are found in extant life forms, the archaeal-type, PolB-based system evolved first and had already given rise to a variety of diverse viruses and other selfish elements before the advent of the bacterial, PolC-based machinery. Conceivably, at that stage of evolution, the niches for DNA-viral reproduction have been already filled with viruses replicating with the

  6. Two-dimensional cellular automaton model for simulating structural evolution of binary alloys during solidification

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lin; ZHANG Cai-bei

    2006-01-01

    Two-dimensional cellular automaton(CA) simulations of phase transformations of binary alloys during solidification were reported. The modelling incorporates local concentration and heat changes into a nucleation or growth function, which is utilized by the automaton in a probabilistic fashion. These simulations may provide an efficient method of discovering how the physical processes involved in solidification processes dynamically progress and how they interact with each other during solidification. The simulated results show that the final morphology during solidification is related with the cooling conditions. The established model can be used to evaluate the phase transformation of binary alloys during solidification.

  7. Evolution and regulation of cellular periodic processes: a role for paralogues

    DEFF Research Database (Denmark)

    Trachana, Kalliopi; Jensen, Lars Juhl; Bork, Peer

    2010-01-01

    paralogues. Thus, diverged temporal expression of paralogues seems to facilitate cellular orchestration under different periodic stimuli. Lineage-specific functional repertoires of periodic-associated paralogues imply that this mode of regulation might have evolved independently in several organisms....... performed the first systematic comparison in three organisms (Homo sapiens, Arabidopsis thaliana and Saccharomyces cerevisiae) by using public microarray data. We observed that although diurnal-regulated and ultradian-regulated genes are not generally cell-cycle-regulated, they tend to have cell-cycle-regulated...

  8. Relative rate and location of intra-host HIV evolution to evade cellular immunity are predictable.

    Science.gov (United States)

    Barton, John P; Goonetilleke, Nilu; Butler, Thomas C; Walker, Bruce D; McMichael, Andrew J; Chakraborty, Arup K

    2016-01-01

    Human immunodeficiency virus (HIV) evolves within infected persons to escape being destroyed by the host immune system, thereby preventing effective immune control of infection. Here, we combine methods from evolutionary dynamics and statistical physics to simulate in vivo HIV sequence evolution, predicting the relative rate of escape and the location of escape mutations in response to T-cell-mediated immune pressure in a cohort of 17 persons with acute HIV infection. Predicted and clinically observed times to escape immune responses agree well, and we show that the mutational pathways to escape depend on the viral sequence background due to epistatic interactions. The ability to predict escape pathways and the duration over which control is maintained by specific immune responses open the door to rational design of immunotherapeutic strategies that might enable long-term control of HIV infection. Our approach enables intra-host evolution of a human pathogen to be predicted in a probabilistic framework. PMID:27212475

  9. A Sharing- and Competition-Aware Framework for Cellular Network Evolution Planning

    OpenAIRE

    Di Francesco, Paolo; Malandrino, Francesco; Forde, Tim K.; Dasilva, Luiz A.

    2015-01-01

    Mobile network operators are facing the difficult task of significantly increasing capacity to meet projected demand while keeping CAPEX and OPEX down. We argue that infrastructure sharing is a key consideration in operators' planning of the evolution of their networks, and that such planning can be viewed as a stage in the cognitive cycle. In this paper, we present a framework to model this planning process while taking into account both the ability to share resources and the constraints imp...

  10. 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

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

    Directory of Open Access Journals (Sweden)

    C. Harman

    2013-05-01

    Full Text Available 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

  12. 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

  13. 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

  14. Cellular automaton simulation of microstructure evolution during austenite decomposition under continuous cooling conditions

    Indian Academy of Sciences (India)

    M R Varma; R Sasikumar; S G K Pillai; P K Nair

    2001-06-01

    A two-dimensional diffusion based model is developed to describe transformation of austenite into ferrite and pearlite under continuous cooling conditions. The nucleation of ferrite is assumed to occur over grain boundaries and the nucleation of pearlite is assumed to be taking place all over the grain and at growing ferrite–austenite interfaces, when the composition and temperature conditions are favourable. A cellular automaton algorithm, with transformation rules based on this model is used for the growth of ferrite and pearlite. Model predicted results for continuous cooling transformations are verified by comparing the model predicted microstructure features with the experimental measurements for two sets of plain carbon steels of different composition and austenite grain size. Using the model, it is possible to generate results like undercooling to start ferrite and pearlite transformations, which are difficult to obtain experimentally.

  15. Darwinian drift: Effects of Wake Vortices and Multiple Obstacles

    Science.gov (United States)

    Melkoumian, Sergei; Protas, Bartosz

    2015-11-01

    When a body passes through an unbounded fluid, it induces a net displacement of fluid particles. The difference between the initial and final positions of a fluid particle is defined as the Darwinian drift and plays an important role in the characterization of the stirring occurring in multiphase flows and in the context of biogenic mixing. Traditional studies of drift have mainly focused on single obstacles moving in a potential flow. In the present investigation we consider the effect of wake vorticity, represented by a pair of Föppl point vortices, and the combined effect of multiple obstacles. The drift in various configurations is determined using methods of complex analysis and careful numerical computations. It is demonstrated that, while the total drift increases with the size of the wake for large vortex strengths, it is actually decreased for small circulation values. We also discuss how the interaction of two obstacles affects the drift in comparison to the case of two isolated obstacles. In particular, we identify the lower and upper bound on the drift due to two identical cylinders. In certain cases our results are supported by asymptotic analysis. A physical explanation of the observed affects is offered in terms of the trajectories of individual particles.

  16. Impact of the human egalitarian syndrome on darwinian selection mechanics.

    Science.gov (United States)

    Boehm, C

    1997-07-01

    With nothing more than kin selection and reciprocal altruism theories to work with, the selection basis of human degrees of altruism and cooperation is often difficult to explain. However, during our prehistoric foraging phase, a highly stable egalitarian syndrome arose that had profound effects on Darwinian selection mechanics. The band's insistence on egalitarianism seriously damped male status rivalry and thereby reduced the intensity of selection within the group by reducing phenotypic variation at that level, while powerful social pressure to make decisions consensual at the band level had a similar effect. Consensual decisions also had another effect: they increased variation between groups because entire bands enacted their subsistence strategies collectively and the strategies varied between bands. By reducing the intensity of individual selection and boosting group effects, these behaviors provided a unique opportunity for altruistic genes to be established and maintained. In addition, the egalitarian custom of socially isolating or actively punishing lazy or cheating noncooperators reduced the free-rider problem. In combination, these phenotypic effects facilitated selection of altruistic genes in spite of some limited free riding. This selection scenario remained in place for thousands of generations, and the result was a shift in the balance of power between individual and group selection in favor of group effects. This new balance today is reflected in an ambivalent human nature that exhibits substantial altruism in addition to selfishness and nepotism. PMID:18811308

  17. Endometriosis: A New Cellular and Molecular Genetic Approach for understanding the pathogenesis and evolutivity

    Directory of Open Access Journals (Sweden)

    Jean eBouquet De Joliniere

    2014-05-01

    Full Text Available ABSTRACT. Endometriosis is a benign disease with high prevalence in women of reproductive age estimated between 10 and 15% and is associated with considerable morbidity. Its etiology and pathogenesis are controversial but it is believed to involve multiple genetic, environmental, immunological, angiogenic and endocrine processes. Altered expressions of growth factors, cytokines, adhesion molecules, matrix metalloproteinases, and enzymes for estrogen synthesis and metabolism have been frequently observed in this condition. The possibility of genetic basis of endometriosis is demonstrated in studies of familial disease, in which the incidence of endometriosis is higher for first-degree relatives of probands as compared to controls. This review describes mainly the cellular, cytochemical, cytogenetic and molecular genetic features of endometriotic lesions and cultured endometriotic cells. In attempts to identify candidate gene (s involved in the pathogenesis of endometriosis, a tissue-based approaches including conventional cytogenetics (RHG-banding, loss of heterozygosity (LOH and Comparative Genomic Hybridization (CGH were employed. In addition to the karyotipic anomalies, consistent chromosome instability was confirmed by CGH and Fluorescence in Situ Hybridization (FISH. The nature and significance of the molecular genetic aberrations in relation to the locations and function of oncogenes and tumor supressor genes will be discussed. At last, a possible pathogenic role of embryonic duct remnants was observed in 7 female foetal reproductive tract in endometriosis and may induce a discussion about the begining of ovarian tumors and malignant proliferations

  18. A multimodal Darwinian strategy for alleviating the atherosclerosis pandemic.

    Science.gov (United States)

    Mathew, Geetha; Thambi, Magith; Unnikrishnan, M K

    2014-02-01

    The conflict between our 'primitive' genes and 'modern' lifestyle probably lies at the root of several disorders that afflict modern man. Atherosclerosis, which is relatively unknown among contemporary hunter-gatherer populations, has reached pandemic proportions in recent times. Being an evolutionary problem with several inter-related pathologies, current therapeutic strategy for treating atherosclerosis has inherent limitations. Reviewing evolution-linked risk factors suggests that there are four aspects to the etiology of atherosclerosis namely, decreased intestinal parasitism, oversensitivity of evolutionarily redundant mast cells, chronic underactivation of AMPK (cellular energy sensor) and a deficiency of vitamin D. A combination of these four causes appear to have precipitated the atherosclerosis pandemic in modern times. Man and worms co-existed symbiotically in the past. Massive de-worming campaigns could have disrupted this symbiosis, increasing nutritional availability to man (pro-obesity) at the cost of decreased immunotolerance (pro-atherogenicity). A reduction in helminth-induced chronic TH2 activation could also have enhanced TH1 polarization, eventually disrupting the reciprocal regulation of TH1/TH2 balance and resulting in atherosclerosis. The riddance of helminth infestations may have rendered mast cells immunologically redundant, making them oversensitive to inflammatory stimuli, thereby playing a pro-atherogenic role. AMPK activation exerts pleiotropic anti-atherogenic effects, such as suppression of fatty acid, cholesterol, protein synthesis, reduction of vascular smooth muscle proliferation, etc. As energy deficit is the chief stimulus for AMPK activation, the over-nourished modern man appears to be suffering from chronic underactivation of AMPK, legitimising the unrivalled supremacy of metformin, the oldest prescribed antidiabetic drug. The fact that humans evolved in the sunny tropics suggests that humans are selected for high vitamin D

  19. 146号初等元胞自动机的演化语言的复杂性%COMPLEXITY OF EVOLUTION LANGUAGES OF THE ELEMENTARY CELLULAR AUTOMATON OF RULE 146

    Institute of Scientific and Technical Information of China (English)

    王益; Morita Kenichi

    2006-01-01

    Symbolic dynamics of cellular automata is introduced by coarse-graining the temporal evolution orbits. Evolution languages are defined. By using the theory of formal languages and automata, the complexity of evolution languages of the elementary cellular automaton of rule 146 is studied and it is proved that its width 1-evolution language is regular, but for every n ≥ 2 its width n-evolution language is not context-free but context-sensitive. Also, the same results hold for the equivalent (under conjugation) elementary cellular automaton of rule 182.

  20. 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”.

  1. 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.

  2. Niching in derandomized evolution strategies and its applications in quantum control

    NARCIS (Netherlands)

    Shir, Ofer Michael

    2008-01-01

    Evolutionary Algorithms (EAs), computational problem-solvers, encode complex problems into an artificial biological environment, define its genetic operators and simulate its propagation in time. Motivated by Darwinian Evolution, it is suggested that such simulations would yield an optimal solution

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

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-Feng; P.Ao

    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 ba/ance 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.

  4. The Scandinavian Connection: The Roots of Darwinian Archaeology in 19th-Century Scandinavian Archaeology

    Directory of Open Access Journals (Sweden)

    Felix Riede

    2006-05-01

    Full Text Available ‘Evolution’ is without doubt one of archaeology’s favourite, most used and perhaps most overused words. However, ‘evolution’ comes in many guises and it is only really in the last ten years that an explicitly Darwinian approach to the archaeological record has begun to emerge. Today, the number of papers using Darwinian Theory grows almost exponentially, reflecting perhaps the current popularity of applying Darwinian Theory to human behaviour, including culture, in more general terms (Aunger 2000; Barrett et al. 2002; Laland andamp; Brown 2002; Mesoudi et al. 2004; Ziman 2000. The field has developed its own technical jargon (Hart andamp; Terrell 2002 and enjoys increasing public funding. Here is not the place to list, let alone discuss the entire corpus of works (but see http://cladistics.coas.missouri.edu/pubs.html and http://www.ceacb.ucl.ac.uk/resources. Instead this brief papers attempts to address some historical aspects of Darwinian thinking in archaeology. Although there is considerable diversity within this Darwinian or Evolutionary Archaeology (EA, this paper will focus primarily on its two most vocal American proponents: Michael J. O’Brien and Richard Lee Lyman. In a long series of publications they have not only put forward a “radically empiricist” (Shennan 2002a: 255, yet eminently workable Darwinian approach to artefact analysis, but they have also traced the intellectual ancestry of EA back to a number of key figures in early 20th century Americanist archaeology (Lyman et al. 1997b; Lyman andamp; O’Brien 1997, 1999, 2000a, 2001, 2003, 2004; Lyman et al. 1997a, 1997b; Lyman et al. 1998; O’Brien et al. 2005. Despite the impressive amount of scholarship that has gone into these works and the exemplary publication strategy, which has been instrumental in promoting this particular approach, their version of the history of archaeology can be criticised as the writing of “partial histories” (Murray 2002a: 234. As

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

    OpenAIRE

    Daniel Walter Brown

    2010-01-01

    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 scien...

  6. Asymptotic Income Distribution in the German Socio-Economic Panel (SOEP): Income Inequality and Darwinian Fitness

    OpenAIRE

    Diego Montano

    2011-01-01

    In this paper, the relation between income inequality and population growth is analized from a Darwinian perspective. A Markov chain population growth model is presented and estimated using data from the German Socio-Economic Panel (SOEP). We estimate both population growth rates and steady-state income distribution for males and females. The results are compatible with the traditional age-based population growth models of demography, in so far as these are actually irreducible, positive-recu...

  7. 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.

  8. The Theory of Evolution: An Educational Perspective.

    Science.gov (United States)

    Johnson, William L.; Johnson, Annabel M.

    The article's thesis is that evolution's intellectual foundations have been steadily eroding, and that few new findings in embryology, taxonomy, fossil remains, and molecular biology are bringing us very near to a formal, logical disproof of Darwinian claims. The paper begins by discussing the evidence of a prehistoric world, then they discuss…

  9. 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…

  10. 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. PMID:26933680

  11. Evolution of Envelope Sequences of Human Immunodeficiency Virus Type 1 in Cellular Reservoirs in the Setting of Potent Antiviral Therapy

    OpenAIRE

    Gunthard, HF; Frost, SDW; Leigh Brown, AJ; Ignacio, CC; Kee, K; Perelson, AS; Spina, CA; Havlir, DV; Hezareh, M; Looney, DJ; Richman, DD; Wong, JK

    1999-01-01

    In human immunodeficiency virus (HIV)-infected patients treated with potent antiretroviral therapy, the persistence of latently infected cells may reflect the long decay half-life of this cellular reservoir or ongoing viral replication at low levels with continuous replenishment of the population or both. To address these possibilities, sequences encompassing the C2 and V3 domains of HIV-1 env were analyzed from virus present in baseline plasma and from viral isolates obtained after 2 years o...

  12. Reconstructing the emergence of cellular life through the synthesis of model protocells.

    Science.gov (United States)

    Mansy, S S; Szostak, J W

    2009-01-01

    The complexity of modern biological life has long made it difficult to understand how life could emerge spontaneously from the chemistry of the early earth. The key to resolving this mystery lies in the simplicity of the earliest living cells, together with the ability of the appropriate molecular building blocks to spontaneously self-assemble into larger structures. In our view, the two key components of a primitive cell are not only self-assembling, but also self-replicating, structures: the nucleic acid genome and the cell membrane. Here, we summarize recent experimental progress toward the synthesis of efficient self-replicating nucleic acid and membrane vesicle systems and discuss some of the issues that arise during efforts to integrate these two subsystems into a coherent whole. We have shown that spontaneous nucleic-acid-copying chemistry can take place within membrane vesicles, using externally supplied activated nucleotides as substrates. Thus, membranes need not be a barrier to the uptake of environmentally supplied nutrients. We examine some of the remaining obstacles that must be overcome to enable the synthesis of a complete self-replicating protocell, and we discuss the implications of these experiments for our understanding of the emergence of Darwinian evolution and the origin and early evolution of cellular life. PMID:19734203

  13. THE EVOLUTION OF ISOLATED BILATERAL LUNG CONTUSION FROM BLUNT CHEST TRAUMA IN RATS: CELLULAR AND CYTOKINE RESPONSES

    OpenAIRE

    Raghavendran, Krishnan; Davidson, Bruce A.; Woytash, James A.; Helinski, Jadwiga D.; Marschke, Cristi J.; Manderscheid, Patricia A.; Notter, Robert H.; Paul R. Knight

    2005-01-01

    Lung contusion is the leading cause of death from blunt thoracic trauma in adults, but its mechanistic pathophysiology remains unclear. This study uses a recently developed rat model to investigate the evolution of inflammation and injury in isolated lung contusion. Bilateral lung contusion with minimal cardiac trauma was induced in 54 anesthetized rats by dropping a 0.3-kg hollow cylindrical weight onto a precordial shield (impact energy, 2.45 Joules). Arterial oxygenation, pressure-volume (...

  14. 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.

  15. Simulation of the texture evolution of aluminum alloys during primary static recrystallization using a cellular automaton approach

    Energy Technology Data Exchange (ETDEWEB)

    Marx, V.; Gottstein, G. [RWTH Aachen (Germany). Inst. fuer Metallkunde und Metallphysik

    1998-12-31

    A 3D model has been developed to simulate both primary static recrystallization and recovery of cold worked aluminum alloys. The model is based on a modified cellular automaton approach and incorporates the influence of crystallographic texture and microstructure in respect to both mechanisms mentioned above. The model takes into account oriented nucleation using an approach developed by Nes for aluminum alloys. The subsequent growth of the nuclei depends on the local stored energy of the deformed matrix (i.e. the driving pressure) and the misorientation between a growing nucleus and its surrounding matrix (i.e. the grain boundary mobility). This approach allows to model preferred growth of grains that exhibit maximum growth rate orientation relationship, e.g. for aluminum alloys a 40{degree}<111> relationship with the surrounding matrix. The model simulates kinetics, microstructure and texture development during heat treatment, discrete in time and space.

  16. The evolution of a capacity to build supra-cellular ropes enabled filamentous cyanobacteria to colonize highly erodible substrates.

    Directory of Open Access Journals (Sweden)

    Ferran Garcia-Pichel

    Full Text Available BACKGROUND: Several motile, filamentous cyanobacteria display the ability to self-assemble into tightly woven or twisted groups of filaments that form macroscopic yarns or ropes, and that are often centimeters long and 50-200 microm in diameter. Traditionally, this trait has been the basis for taxonomic definition of several genera, notably Microcoleus and Hydrocoleum, but the trait has not been associated with any plausible function. METHOD AND FINDINGS: Through the use of phylogenetic reconstruction, we demonstrate that pedigreed, rope-building cyanobacteria from various habitats do not form a monophyletic group. This is consistent with the hypothesis that rope-building ability was fixed independently in several discrete clades, likely through processes of convergent evolution or lateral transfer. Because rope-building cyanobacteria share the ability to colonize geologically unstable sedimentary substrates, such as subtidal and intertidal marine sediments and non-vegetated soils, it is also likely that this supracellular differentiation capacity imparts a particular fitness advantage in such habitats. The physics of sediment and soil erosion in fact predict that threads in the 50-200 microm size range will attain optimal characteristics to stabilize such substrates on contact. CONCLUSIONS: Rope building is a supracellular morphological adaptation in filamentous cyanobacteria that allows them to colonize physically unstable sedimentary environments, and to act as successful pioneers in the biostabilization process.

  17. Bioinspired genotype–phenotype linkages: mimicking cellular compartmentalization for the engineering of functional proteins

    OpenAIRE

    Van Vliet, Liisa D.; Colin, Pierre-Yves; Hollfelder, Florian

    2015-01-01

    The idea of compartmentalization of genotype and phenotype in cells is key for enabling Darwinian evolution. This contribution describes bioinspired systems that use in vitro compartments—water-in-oil droplets and gel-shell beads—for the directed evolution of functional proteins. Technologies based on these principles promise to provide easier access to protein-based therapeutics, reagents for processes involving enzyme catalysis, parts for synthetic biology and materials with biological comp...

  18. Reasons Given by UK Churchgoers for Their Stance on Evolution

    Science.gov (United States)

    Village, Andrew; Baker, Sylvia

    2013-01-01

    A sample of 661 churchgoers from a range of Christian denominations in the United Kingdom was asked about Darwinian evolution (defined as the common origin of all species, including humans). Respondents were categorised as those who accepted the idea, those who rejected it, and those who were unsure or neutral. People in each category were given a…

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

    Science.gov (United States)

    Green, Lisa Anne

    2012-01-01

    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…

  20. Constructive neutral evolution: exploring evolutionary theory’s curious disconnect

    OpenAIRE

    Stoltzfus Arlin

    2012-01-01

    Abstract Constructive neutral evolution (CNE) suggests that neutral evolution may follow a stepwise path to extravagance. Whether or not CNE is common, the mere possibility raises provocative questions about causation: in classical neo-Darwinian thinking, selection is the sole source of creativity and direction, the only force that can cause trends or build complex features. However, much of contemporary evolutionary genetics departs from the conception of evolution underlying neo-Darwinism, ...

  1. Evolution in the Multiverse

    CERN Document Server

    Standish, R K

    2000-01-01

    In the {\\em Many Worlds Interpretation} of quantum mechanics, the range of possible worlds (or histories) provides variation, and the Anthropic Principle is a selective principle analogous to natural selection. When looked on in this way, the ``process'' by which the laws and constants of physics is determined not too different from the process that gave rise to our current biodiversity, i.e. Darwinian evolution. This has implications for the fields of SETI and Artificial Life, which are based on a philosophy of the inevitability of life.

  2. 用达尔文医学的观点看待近视眼的发生和治疗%Darwinian Medicine View of the Occurrence and Treatment of Myopia

    Institute of Scientific and Technical Information of China (English)

    赵宏伟; 刘怡

    2013-01-01

    从近视眼的进化史来看,伴随人类生活方式的改变,眼睛对近距离信息摄取的需求膨胀是近视眼形成的终因.在漫长的人类历史中,近视眼获得的每一种益处,都伴随着相应的代价.而达尔文医学关于生物进化的不完美性决定了近视眼的进化适应和代价将长期共存.因此,从治疗模式来看,应该摒弃达尔文医学固有的消极性而考虑生物的整体性和生态性.近视眼的中医和基因治疗正是避免了达尔文医学治疗模式的理论消极性,而且融入了其有关生物进化、遗传与环境统一的部分理念,可能成为近视眼治疗的候选策略.%Accompanied with change of human life-style,a large amount of information intake by eyes from close distance is the end reason of myopia formation from evolution history of myopia.Every benefit from myopia accompany its cost during the human beings history.However,myopia evolutionary benefits and costs have been and will coexist for a long time due to imperfect biological evolution from Darwinian medicine.Therefore,from the mode of treatment,we should give up the inherent negativity and consider the biological integrity and ecological of Darwinian medicine.The traditional Chinese medicine and gene therapy against to myopia may become the candidate strategy,because they avoid negativity of Darwin medical,involved the idea of biological evolution and unitary between gene and environment from Darwinian medicine.Traditional Chinese medicine and gene therapy of myopia.

  3. Punctuated equilibrium in statistical models of generalized coevolutionary resilience: How sudden ecosystem transitions can entrain both phenotype expression and Darwinian selection

    OpenAIRE

    Wallace, Dr. Rodrick; Wallace, Dr. Deborah

    2008-01-01

    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 ...

  4. Model of Interaction between Learning and Evolution

    OpenAIRE

    Red'ko, Vladimir G.

    2014-01-01

    The model of interaction between learning and evolutionary optimization is designed and investigated. The evolving population of modeled organisms is considered. The mechanism of the genetic assimilation of the acquired features during a number of generations of Darwinian evolution is studied. It is shown that the genetic assimilation takes place as follows: phenotypes of modeled organisms move towards the optimum at learning; then the selection takes place; genotypes of selected organisms al...

  5. Structural calibration of the rates of amino acid evolution in a search for Darwin in drifting biological systems.

    Science.gov (United States)

    Toft, Christina; Fares, Mario A

    2010-10-01

    In the last two decades, many reports of proteins under positive selection have brought the neutral theory into question. However, the methods used to detect selection have ignored the evolvability of amino acids within proteins, which is fundamental to distinguishing positive selection from the relaxed constraints caused by genetic drift. Disentangling these two counterbalancing forces is essential to test the neutral theory. Here, we calibrate rates of amino acid divergence by using structural information from the full set of crystallized proteins in bacteria. In agreement with previous reports, we show that rates of amino acid evolution correlate negatively with the number of per-amino acid atomic interactions. Calibration of the rates of evolution allows identifying signatures of selection in biological systems that evolve under strong genetic drift, such as endosymbiotic bacteria. Application of this method identifies different rates and dynamics of evolution for highly connected amino acids in the structure compared with sparsely connected ones. We also unearth patterns of Darwinian selection in fundamental cellular proteins in endosymbiotic bacteria including the cochaperonin GroES, ribosomal proteins, proteins involved in cell cycle control, DNA-binding proteins, and proteins involved in DNA replication and repair. This is, to our knowledge, the first attempt to distinguish adaptive evolution from relaxed constraints in biological systems under genetic drift. PMID:20466746

  6. Cultural transmission can inhibit the evolution of altruistic helping.

    OpenAIRE

    Lehmann L.; Feldman M.W.; Foster K.R.

    2008-01-01

    The study of culturally inherited traits has led to the suggestion that the evolution of helping behaviors is more likely with cultural transmission than without. Here we evaluate this idea through a comparative analysis of selection on helping under both genetic and cultural inheritance. We develop two simple models for the evolution of helping through cultural group selection: one in which selection on the trait depends solely on Darwinian fitness effects and one in which selection is drive...

  7. Phylogenomic evidence of adaptive evolution in the ancestry of humans

    OpenAIRE

    Goodman, Morris; Sterner, Kirstin N.

    2010-01-01

    In Charles Darwin’s tree model for life’s evolution, natural selection adaptively modifies newly arisen species as they branch apart from their common ancestor. In accord with this Darwinian concept, the phylogenomic approach to elucidating adaptive evolution in genes and genomes in the ancestry of modern humans requires a well supported and well sampled phylogeny that accurately places humans and other primates and mammals with respect to one another. For more than a century, first from the ...

  8. Recombination dramatically speeds up evolution of finite populations

    OpenAIRE

    Cohen, Elisheva; Kessler, David A.; Levine, Herbert

    2004-01-01

    We study the role of recombination, as practiced by genetically-competent bacteria, in speeding up Darwinian evolution. This is done by adding a new process to a previously-studied Markov model of evolution on a smooth fitness landscape; this new process allows alleles to be exchanged with those in the surrounding medium. Our results, both numerical and analytic, indicate that for a wide range of intermediate population sizes, recombination dramatically speeds up the evolutionary advance.

  9. The Darwinian muddle on the division of labour: an attempt at clarification.

    Science.gov (United States)

    D'Hombres, Emmanuel

    2016-04-01

    It is of philosophical and epistemological interest to examine how Darwin conceived the process of division of labour within Natural History. Darwin observed the advantages brought by division of labour to the human economy, and considered that the principle of divergence within nature, which is, according to him, one of the two 'keystones' of his theory, gave comparable advantages. This led him to re-examine Milne-Edwards' view on the notion of division of physiological labour, and to introduce this with modifications into his naturalist writings. After a short review of the Darwinian historiography dealing with this issue, I first show the conceptual confusion into which Darwin plunges, when using a so-called economic argument to defend his thesis of the maximization of beings in a given territory due to division of labour. Following this I propose several hypotheses to explain these shifts, recurring in Darwin's texts, from one conception and from one application to another, of the division of labour. PMID:26463099

  10. Extending the fractional order Darwinian particle swarm optimization to segmentation of hyperspectral images

    Science.gov (United States)

    Ghamisi, Pedram; Couceiro, Micael S.; Benediktsson, Jon Atli

    2012-11-01

    Hyperspectral sensors generate detailed information about the earth's surface and climate in numerous contiguous narrow spectral bands, being widely used in resource management, agriculture, environmental monitoring, and others. However, due to the high dimensionality of hyperspectral data, it is difficult to design accurate and efficient image segmentation algorithms for hyperspectral imagery. In this paper a new multilevel thresholding method for segmentation of hyperspectral images into different homogenous regions is proposed. The new method is based on the Fractional-Order Darwinian Particle Swarm Optimization (FODPSO) which exploits the many swarms of test solutions that may exist at any time. In addition, the concept of fractional derivative is used to control the convergence rate of particles. The FODPSO is used to solve the so-called Otsu problem for each channel of the hyperspectral data as a grayscale image that indicates the spectral response to a particular frequency in the electromagnetic spectrum. In other words, the problem of n-level thresholding is reduced to an optimization problem in order to search for the thresholds that maximize the between-class variance. Experimental results successfully compare the FODPSO with the traditional PSO for multi-level segmentation of hyperspectral images. The FODPSO acts better than the other method in terms of both CPU time and fitness, thus being able to find the optimal set of thresholds with a larger between-class variance in less computational time.

  11. Cellular automata

    CERN Document Server

    Codd, E F

    1968-01-01

    Cellular Automata presents the fundamental principles of homogeneous cellular systems. This book discusses the possibility of biochemical computers with self-reproducing capability.Organized into eight chapters, this book begins with an overview of some theorems dealing with conditions under which universal computation and construction can be exhibited in cellular spaces. This text then presents a design for a machine embedded in a cellular space or a machine that can compute all computable functions and construct a replica of itself in any accessible and sufficiently large region of t

  12. More genes underwent positive selection in chimpanzee evolution than in human evolution

    OpenAIRE

    Bakewell, Margaret A.; Shi, Peng; Zhang, Jianzhi

    2007-01-01

    Observations of numerous dramatic and presumably adaptive phenotypic modifications during human evolution prompt the common belief that more genes have undergone positive Darwinian selection in the human lineage than in the chimpanzee lineage since their evolutionary divergence 6–7 million years ago. Here, we test this hypothesis by analyzing nearly 14,000 genes of humans and chimps. To ensure an accurate and unbiased comparison, we select a proper outgroup, avoid sequencing errors, and verif...

  13. Genetic variability, individuality and the evolution of the mammalian brain.

    Science.gov (United States)

    Lipp, H P

    1995-12-01

    The neo-Darwinian theory of evolution has difficulty in explaining the rapid evolution of mammalian brain and behavior. I shall argue that the plasticity mechanisms of the brain (i.e., system homeostasis, developmental reorganization, structural adult plasticity, and cognition and learning) have evolved primarily as genetic buffer systems which protect subtle mutations influencing brain structures from natural selection. These buffer systems permit accumulation of genetic variation in the higher system levels of the brain (simply defined as structures with late differentiation), while low-level systems are kept constant by natural selection. The organization of this intrinsic genetic buffering system provides several features facilitating neo-Darwinian evolution: In conclusion, the evolutionary appearance of cognition and intelligence is an ordinary biological mechanism compensating evolutionary drags such as long lifespans and fewer offspring. The concept has heuristic value for identifying gene-brain-behavior relationships and for explaining behavioral consequences of artifical gene deletions. PMID:24896017

  14. 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…

  15. 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…

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

    OpenAIRE

    Takehiro Nishikawa; Takeshi Sunami; Tomoaki Matsuura; Tetsuya Yomo

    2012-01-01

    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 I...

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

    Science.gov (United States)

    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 plankton when water-immersed, negatively pressured suction bladders are triggered. The resetting of traps involves active ion transport, requiring considerable energy expenditure. As judged from the quaternary structure of bovine COX, the most profound adaptive substitutions are two contiguous cysteines absent in ≈99.9% of databased COX I sequences from Eukaryota, Archaea, and Bacteria. This motif lies directly at the docking point of COX I helix 3 and cytochrome c, and modeling of bovine COX I suggests the possibility of an unprecedented helix-terminating disulfide bridge that could alter COX/cytochrome c dissociation kinetics. Thus, the key adaptation in Utricularia likely lies in molecular energetic changes that buttressed the mechanisms responsible for the bladderworts' radical morphological evolution. Along with evidence for COX evolution underlying expansion of the anthropoid neocortex, our findings underscore that important morphological and physiological innovations must often be accompanied by specific adaptations in proteins with basic cellular functions. PMID:15596720

  18. Darwinian Dynamics of Intratumoral Heterogeneity: Not Solely Random Mutations but Also Variable Environmental Selection Forces.

    Science.gov (United States)

    Lloyd, Mark C; Cunningham, Jessica J; Bui, Marilyn M; Gillies, Robert J; Brown, Joel S; Gatenby, Robert A

    2016-06-01

    Spatial heterogeneity in tumors is generally thought to result from branching clonal evolution driven by random mutations that accumulate during tumor development. However, this concept rests on the implicit assumption that cancer cells never evolve to a fitness maximum because they can always acquire mutations that increase proliferative capacity. In this study, we investigated the validity of this assumption. Using evolutionary game theory, we demonstrate that local cancer cell populations will rapidly converge to the fittest phenotype given a stable environment. In such settings, cellular spatial heterogeneity in a tumor will be largely governed by regional variations in environmental conditions, for example, alterations in blood flow. Model simulations specifically predict a common spatial pattern in which cancer cells at the tumor-host interface exhibit invasion-promoting, rapidly proliferating phenotypic properties, whereas cells in the tumor core maximize their population density by promoting supportive tissue infrastructures, for example, to promote angiogenesis. We tested model predictions through detailed quantitative image analysis of phenotypic spatial distribution in histologic sections of 10 patients with stage 2 invasive breast cancers. CAIX, GLUT1, and Ki67 were upregulated in the tumor edge, consistent with an acid-producing invasive, proliferative phenotype. Cells in the tumor core were 20% denser than the edge, exhibiting upregulation of CAXII, HIF-1α, and cleaved caspase-3, consistent with a more static and less proliferative phenotype. Similarly, vascularity was consistently lower in the tumor center compared with the tumor edges. Lymphocytic immune responses to tumor antigens also trended to higher level in the tumor edge, although this effect did not reach statistical significance. Like invasive species in nature, cancer cells at the leading edge of the tumor possess a different phenotype from cells in the tumor core. Our results suggest

  19. 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.

  20. Directed Evolution of Glutathione Transferases with Altered Substrate Selectivity Profiles : A Laboratory Evolution Study Shedding Light on the Multidimensional Nature of Epistasis

    OpenAIRE

    Zhang, Wei

    2011-01-01

    Directed evolution is generally regarded as a useful approach in protein engineering. By subjecting members of a mutant library to the power of Darwinian evolution, desired protein properties are obtained. Numerous reports have appeared in the literature showing the success of tailoring proteins for various applications by this method. Is it a one-way track that protein practitioners can only learn from nature to enable more efficient protein engineering? A structure-and-mechanism-based appro...

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

    OpenAIRE

    Galor, Oded; Michalopoulos, Stelios

    2011-01-01

    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 ...

  2. Cellular Automata

    OpenAIRE

    Bagnoli, Franco

    1998-01-01

    An introduction to cellular automata (both deterministic and probabilistic) with examples. Definition of deterministic automata, dynamical properties, damage spreading and Lyapunov exponents; probabilistic automata and Markov processes, nonequilibrium phase transitions, directed percolation, diffusion; simulation techniques, mean field. Investigation themes: life, epidemics, forest fires, percolation, modeling of ecosystems and speciation. They represent my notes for the school "Dynamical Mod...

  3. Small Open Chemical Systems Theory: Its Implications to Darwinian Evolution Dynamics, Complex Self-Organization and Beyond

    International Nuclear Information System (INIS)

    The study of biological cells in terms of mesoscopic, nonequilibrium, nonlinear, stochastic dynamics of open chemical systems provides a paradigm for other complex, self-organizing systems with ultra-fast stochastic fluctuations, short-time deterministic nonlinear dynamics, and long-time evolutionary behavior with exponentially distributed rare events, discrete jumps among punctuated equilibria, and catastrophe. (general)

  4. Dynamics of Similar Populations: The Link Between Population Dynamics and Evolution

    OpenAIRE

    Meszena, G.; Gyllenberg, M.; F.J.A. Jacobs; J.A.J. Metz

    2005-01-01

    We provide the link between population dynamics and the dynamics of Darwinian evolution via studying the joint population dynamics of "similar" populations. Similarity implies that the "relative" dynamics of the populations is slow compared to, and decoupled from, their "aggregated" dynamics. The relative dynamics is simple, and captured by a Taylor expansion in the difference between the populations. The emerging evolution is directional, except at the "singular" points of the evolutionary s...

  5. A Saltationist Approach for the Evolution of Human Cognition and Language

    OpenAIRE

    Lanyon, Susan J.

    2006-01-01

    The debate over the evolution of an innate language capacity seems to divide into two principle camps. The neo-Darwinian approach generally argues that human psychological modules, including the language faculty, must have arisen gradually and incrementally having been honed by natural selection. Thus Pinker, when theorizing about language evolution, sees ``no reason to doubt that the principle explanation is the same as for any other complex instinct or organ, Darwin's theory of natural sele...

  6. Cellular resilience.

    Science.gov (United States)

    Smirnova, Lena; Harris, Georgina; Leist, Marcel; Hartung, Thomas

    2015-01-01

    Cellular resilience describes the ability of a cell to cope with environmental changes such as toxicant exposure. If cellular metabolism does not collapse directly after the hit or end in programmed cell death, the ensuing stress responses promote a new homeostasis under stress. The processes of reverting "back to normal" and reversal of apoptosis ("anastasis") have been studied little at the cellular level. Cell types show astonishingly similar vulnerability to most toxicants, except for those that require a very specific target, metabolism or mechanism present only in specific cell types. The majority of chemicals triggers "general cytotoxicity" in any cell at similar concentrations. We hypothesize that cells differ less in their vulnerability to a given toxicant than in their resilience (coping with the "hit"). In many cases, cells do not return to the naive state after a toxic insult. The phenomena of "pre-conditioning", "tolerance" and "hormesis" describe this for low-dose exposures to toxicants that render the cell more resistant to subsequent hits. The defense and resilience programs include epigenetic changes that leave a "memory/scar" - an alteration as a consequence of the stress the cell has experienced. These memories might have long-term consequences, both positive (resistance) and negative, that contribute to chronic and delayed manifestations of hazard and, ultimately, disease. This article calls for more systematic analyses of how cells cope with toxic perturbations in the long-term after stressor withdrawal. A technical prerequisite for these are stable (organotypic) cultures and a characterization of stress response molecular networks. PMID:26536287

  7. Widespread adaptive evolution during repeated evolutionary radiations in New World lupins

    Science.gov (United States)

    Nevado, Bruno; Atchison, Guy W.; Hughes, Colin E.; Filatov, Dmitry A.

    2016-01-01

    The evolutionary processes that drive rapid species diversification are poorly understood. In particular, it is unclear whether Darwinian adaptation or non-adaptive processes are the primary drivers of explosive species diversifications. Here we show that repeated rapid radiations within New World lupins (Lupinus, Leguminosae) were underpinned by a major increase in the frequency of adaptation acting on coding and regulatory changes genome-wide. This contrasts with far less frequent adaptation in genomes of slowly diversifying lupins and all other plant genera analysed. Furthermore, widespread shifts in optimal gene expression coincided with shifts to high rates of diversification and evolution of perenniality, a putative key adaptation trait thought to have triggered the evolutionary radiations in New World lupins. Our results reconcile long-standing debate about the relative importance of protein-coding and regulatory evolution, and represent the first unambiguous evidence for the rapid onset of lineage- and genome-wide accelerated Darwinian evolution during rapid species diversification. PMID:27498896

  8. 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

  9. Cancer: evolution within a lifetime.

    Science.gov (United States)

    Gerlinger, Marco; McGranahan, Nicholas; Dewhurst, Sally M; Burrell, Rebecca A; Tomlinson, Ian; Swanton, Charles

    2014-01-01

    Subclonal cancer populations change spatially and temporally during the disease course. Studies are revealing branched evolutionary cancer growth with low-frequency driver events present in subpopulations of cells, providing escape mechanisms for targeted therapeutic approaches. Despite such complexity, evidence is emerging for parallel evolution of subclones, mediated through distinct somatic events converging on the same gene, signal transduction pathway, or protein complex in different subclones within the same tumor. Tumors may follow gradualist paths (microevolution) as well as major shifts in evolutionary trajectories (macroevolution). Although macroevolution has been subject to considerable controversy in post-Darwinian evolutionary theory, we review evidence that such nongradual, saltatory leaps, driven through chromosomal rearrangements or genome doubling, may be particularly relevant to tumor evolution. Adapting cancer care to the challenges imposed by tumor micro- and macroevolution and developing deeper insight into parallel evolutionary events may prove central to improving outcome and reducing drug development costs. PMID:25292359

  10. 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…

  11. Cellular Cell Bifurcation of Cylindrical Detonations

    Institute of Scientific and Technical Information of China (English)

    HAN Gui-Lai; JIANG Zong-Lin; WANG Chun; ZHANG Fan

    2008-01-01

    Cellular cell pattern evolution of cylindrically-diverging detonations is numerically simulated successfully by solving two-dimensional Euler equations implemented with an improved two-step chemical kinetic model. From the simulation, three cell bifurcation modes are observed during the evolution and referred to as concave front focusing, kinked and wrinkled wave front instability, and self-merging of cellular cells. Numerical research demonstrates that the wave front expansion resulted from detonation front diverging plays a major role in the cellular cell bifurcation, which can disturb the nonlinearly self-sustained mechanism of detonations and finally lead to cell bifurcations.

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

    International Nuclear Information System (INIS)

    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

  13. Evolutionary psychology and evolutionary developmental psychology: understanding the evolution of human behavior and development

    OpenAIRE

    Hernández Blasi, Carlos; Causey, Kayla

    2010-01-01

    This is an introduction to this special issue on evolutionary psychology (EP) and evolutionary developmental psychology (EDP). We suggest here that, contrary to some common assumptions, mainstream psychology continues to be essentially non Darwinian and that EP and EDP are new approaches that can potentially help us to change this situation. We then present the organization of the special issue (composed of six papers). We conclude that evolution is certainly not the final cons...

  14. The edge of neutral evolution in social dilemmas

    International Nuclear Information System (INIS)

    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.

  15. The Darwinian tension: Romantic science and the causal laws of nature.

    Science.gov (United States)

    Greif, Hajo

    2015-10-01

    There have been attempts to subsume Charles Darwin's theory of evolution under either one of two distinct intellectual traditions: early Victorian natural science and its descendants in political economy (as exemplified by Herschel, Lyell, or Malthus) and the romantic approach to art and science emanating from Germany (as exemplified by Humboldt and Goethe). In this paper, it will be shown how these traditions may have jointly contributed to the design of Darwin's theory. The hypothesis is that their encounter created a particular tension in the conception of his theory which first opened up its characteristic field and mode of explanation. On the one hand, the domain of the explanandum was conceived of under a holistic and aesthetic view of nature that, in its combination with refined techniques of observation, was deeply indebted to Humboldt in particular. On the other hand, Darwin fashioned explanations for natural phenomena, so conceived, in order to identify their proper causes in a Herschelian spirit. The particular interaction between these two traditions in Darwin, it is concluded, paved the way for a transfer of the idea of causal laws to animate nature while salvaging the romantic idea of a complex, teleological and harmonious order of nature. PMID:26258495

  16. Problems of Cosmological Darwinian Selection and the Origin of Habitable Universes

    Science.gov (United States)

    Vaas, Rüdiger

    For the cosmologist and physicist Lee Smolin, our universe is only one in a much larger cosmos (the Multiverse), a member of a growing community of universes, each one being born in a bounce following the formation of a black hole [1,2]. In the course of this, the values of the free parameters of the physical laws are reprocessed and slightly changed in a random way. This leads to an evolutionary picture of the Multiverse, where universes with more black holes have more descendants. Hence, according to Smolin our universe is a product of mutation and selection analogous to the evolution of species described first by Charles Darwin in his seminal book "On the Origin of Species" in 1859 [3]. Smolin concludes, that due to this kind of Cosmological Natural Selection our own universe is the way it is. This is taken as an explanation for the so-called fine-tuning of physical parameters for the existence of earth-like life: They have the values we observe, because they make the formation of black holes much more likely than most other values. - This paper critically comments on some limits of Smolin's hypothesis. A more extended discussion can be found in [4].

  17. Should the teaching of biological evolution include the origin of life?

    OpenAIRE

    Lazcano, A; Peretó, Juli

    2010-01-01

    The development of mainstream research on the origin of life as an outcome of Darwinian evolution is discussed. It is argued that prebiotic evolution and the origin of life should not be excluded from the syllabus and should be part of classes on biological evolution, and that the transition from non-living to living matter is best understood when seen as part of evolutionary biology. The wide acceptance of evolutionary approaches to the study of the emergence of life in European and Latin Am...

  18. The broken branch: Darwin's evolutionary tree and the progress of Medicine, the evolution of specialism and generalism

    OpenAIRE

    Richard V. Lee

    2013-01-01

    The landscape of medical practice and health care has been transformed by specialization over the past Century. There has been an extraordinary acceleration in the proliferation of specialty practice, coincident with rapid growth in technological devices and their clinical applications during the past fifty years. Medicine and medical care are evolving rapidly, a process that has similarities to biologic evolution. Medical educators, policy makers, and practitioners might find a Darwinian ove...

  19. Directed Evolution of Stereoselective Hybrid Catalysts

    Science.gov (United States)

    Reetz, Manfred T.

    Whereas the directed evolution of stereoselective enzymes provides a useful tool in asymmetric catalysis, generality cannot be claimed because enzymes as catalysts are restricted to a limited set of reaction types. Therefore, a new concept has been proposed, namely directed evolution of hybrid catalysts in which proteins serve as hosts for anchoring ligand/transition metal entities. Accordingly, appropriate genetic mutagenesis methods are applied to the gene of a given protein host, providing after expression a library of mutant proteins. These are purified and a ligand/transition metal anchored site-specifically. Following en masse ee-screening, the best hit is identified, and the corresponding mutant gene is used as a template for another round of mutagenesis, expression, purification, bioconjugation, and screening. This allows for a Darwinian optimization of transition metal catalysts.

  20. On the Behavior Characteristics of Cellular Automata

    Institute of Scientific and Technical Information of China (English)

    CHEN Jin-cai; ZHANG Jiang-ling; FENG Dan

    2005-01-01

    In this paper, the inherent relationships between the running regulations and behavior characteristics of cellular automata are presented; an imprecise taxonomy of such systems is put forward; the three extreme cases of stable systems are discussed; and the illogicalness of evolutional strategies of cellular automata is analyzed. The result is suitable for the emulation and prediction of behavior of discrete dynamics systems; especially it can be taken as an important analysis means of dynamic performance of complex networks.

  1. Cellular Hyperproliferation and Cancer as Evolutionary Variables

    OpenAIRE

    Alvarado, Alejandro Sánchez

    2012-01-01

    Technological advances in biology have begun to dramatically change the way we think about evolution, development, health and disease. The ability to sequence the genomes of many individuals within a population, and across multiple species, has opened the door to the possibility of answering some long-standing and perplexing questions about our own genetic heritage. One such question revolves around the nature of cellular hyperproliferation. This cellular behavior is used to effect wound heal...

  2. 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.

  3. Interworking of Wireless LANs and Cellular Networks

    CERN Document Server

    Song, Wei

    2012-01-01

    The next-generation of wireless communications are envisioned to be supported by heterogeneous networks by using various wireless access technologies. The popular cellular networks and wireless local area networks (WLANs) present perfectly complementary characteristics in terms of service capacity, mobility support, and quality-of-service (QoS) provisioning. The cellular/WLAN interworking is an effective way to promote the evolution of wireless networks. "Interworking of Wireless LANs and Cellular Networks" focuses on three aspects, namely access selection, call admission control and

  4. 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'.

  5. A neo-darwinian foundation of evolutionary economics: With an application to the theory of the firm

    OpenAIRE

    Rahmeyer, Fritz

    2010-01-01

    The focus of evolutionary economics is a process of continuous economic and organizational change. Currently there is no agreement on the explanation of economic evolution. Rather there are competing interpretations. To achieve a common understanding of economic evolution, from the perspective of the history of economic thought, at first the theoretical approaches of Schumpeter and Marshall with regard to economic development or evolution are dealt with. After that, a concept of socio-economi...

  6. 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

  7. Darwinian Adverse Selection

    CERN Document Server

    Kuhle, Wolfgang

    2015-01-01

    We develop a model to study the role of rationality in economics and biology. The model's agents differ continuously in their ability to make rational choices. The agents' objective is to ensure their individual survival over time or, equivalently, to maximize profits. In equilibrium, however, rational agents who maximize their objective survival probability are, individually and collectively, eliminated by the forces of competition. Instead of rationality, there emerges a unique distribution of irrational players who are individually not fit for the struggle of survival. The selection of irrational players over rational ones relies on the fact that all rational players coordinate on the same optimal action, which leaves them collectively undiversified and thus vulnerable to aggregate risks.

  8. 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). PMID:15612191

  9. 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.

  10. Mathematical Physics of Cellular Automata

    CERN Document Server

    Garcia-Morales, Vladimir

    2012-01-01

    A universal map is derived for all deterministic 1D cellular automata (CA) containing no freely adjustable parameters. The map can be extended to an arbitrary number of dimensions and topologies and its invariances allow to classify all CA rules into equivalence classes. Complexity in 1D systems is then shown to emerge from the weak symmetry breaking of the addition modulo an integer number p. The latter symmetry is possessed by certain rules that produce Pascal simplices in their time evolution. These results elucidate Wolfram's classification of CA dynamics.

  11. Contributions of experimental protobiogenesis to the theory of evolution

    Science.gov (United States)

    Fox, S. W.

    1976-01-01

    Inferences from experiments in protobiogenesis are examined as a forward extension of the theory of evolutionary biology. A nondiscontinuous, intraconsistent theory of general evolution embracing both protobiology and biology is outlined. This overview emphasizes Darwinian selection in the later stages of evolution, and stereochemical molecular selection in some of its earlier stages. It incorporates the concept of limitation of the scope of evolution by internal constraints on variation, based on the argument that internally limiting constraints observed in experiments with molecules are operative in organisms, if chemical processes occur within biological processes and biological processes are assumed to be exponentializations of chemical processes. Major evolutionary events might have occurred by rapid self-assembly processes analogous to those observed in the formation of phase-separated microspheres from amorphous powder or supersaturated solutions.

  12. Cellular scaling rules for the brain of afrotherians

    OpenAIRE

    Kleber eNeves; Fernanda eMeireles Ferreira; Fernanda eTovar-Moll; Nadine eGravett; Bennett, Nigel C.; Consolate eKaswera; Emmanuel eGilissen; Paul eManger; Suzana eHerculano-Houzel

    2014-01-01

    Quantitative analysis of the cellular composition of rodent, primate and eulipotyphlan brains has shown that nonneuronal scaling rules are similar across these mammalian orders that diverged about 95 million years ago, and therefore appear to be conserved in evolution, while neuronal scaling rules appear to be free to vary in evolution in a clade-specific manner. Here we analyze the cellular scaling rules that apply to the brain of afrotherians, believed to be the first clade to radiate from ...

  13. Cellular scaling rules for the brain of afrotherians

    OpenAIRE

    Neves, Kleber; Ferreira, Fernanda M.; Tovar-Moll, Fernanda; Gravett, Nadine; Bennett, Nigel C.; Kaswera, Consolate; Gilissen, Emmanuel; Manger, Paul R.; Herculano-Houzel, Suzana

    2014-01-01

    Quantitative analysis of the cellular composition of rodent, primate and eulipotyphlan brains has shown that non-neuronal scaling rules are similar across these mammalian orders that diverged about 95 million years ago, and therefore appear to be conserved in evolution, while neuronal scaling rules appear to be free to vary in evolution in a clade-specific manner. Here we analyze the cellular scaling rules that apply to the brain of afrotherians, believed to be the first clade to radiate from...

  14. Modelling cellular behaviour

    Science.gov (United States)

    Endy, Drew; Brent, Roger

    2001-01-01

    Representations of cellular processes that can be used to compute their future behaviour would be of general scientific and practical value. But past attempts to construct such representations have been disappointing. This is now changing. Increases in biological understanding combined with advances in computational methods and in computer power make it possible to foresee construction of useful and predictive simulations of cellular processes.

  15. Is there a Darwinian Evolution of the Cosmos? - Some Comments on Lee Smolin's Theory of the Origin of Universes by Means of Natural Selection

    CERN Document Server

    Vaas, R

    2002-01-01

    For Lee Smolin, our universe is only one in a much larger cosmos (the Multiverse) - a member of a growing community of universes, each one being born in a bounce following the formation of a black hole. In the course of this, the values of the free parameters of the physical laws are reprocessed and slightly changed. This leads to an evolutionary picture of the Multiverse, where universes with more black holes have more descendants. Smolin concludes, that due to this kind of Cosmological Natural Selection our own universe is the way it is. The hospitality for life of our universe is seen as an offshot of this self-organized process. - This paper outlines Smolin's hypothesis, its strength, weakness and limits, its relationship to the anthropic principle and evolutionary biology, and comments on the hypothesis from different points of view: physics, biology, philosophy of science, philosophy of nature, and metaphysics. Some of the main points are: (1) There is no necessary connection between black holes and lif...

  16. Is there a Darwinian Evolution of the Cosmos? - Some Comments on Lee Smolin's Theory of the Origin of Universes by Means of Natural Selection

    OpenAIRE

    Vaas, Ruediger

    2002-01-01

    For Lee Smolin, our universe is only one in a much larger cosmos (the Multiverse) - a member of a growing community of universes, each one being born in a bounce following the formation of a black hole. In the course of this, the values of the free parameters of the physical laws are reprocessed and slightly changed. This leads to an evolutionary picture of the Multiverse, where universes with more black holes have more descendants. Smolin concludes, that due to this kind of Cosmological Natu...

  17. 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.

  18. 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

  19. 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.

  20. From chemical reactions to evolution: Emergence of species

    Science.gov (United States)

    Carletti, T.; Fanelli, D.

    2007-01-01

    The Chemoton model constitutes a minimalistic description of a protocell unit. The original formulation assumes three coupled chemical networks, representing a proto-metabolism, a template duplication and the membrane growth. An improved version is here proposed that explicitly incorporates the effects of the volume changes, due to the membrane growth. A stochastic mechanism is also introduced that mimics a stochastic source of error in the template duplication process. Numerical simulations are performed to monitor the time evolution of a family of protocells, under the chemoton hypothesis. An open-ended Darwinian evolution under the pressure of the environment is reproduced thus allowing to conclude that differentiation into species is an emergent property of the model.

  1. Cellular Therapy for Heart Failure.

    Science.gov (United States)

    Psaltis, Peter J; Schwarz, Nisha; Toledo-Flores, Deborah; Nicholls, Stephen J

    2016-01-01

    The pathogenesis of cardiomyopathy and heart failure (HF) is underpinned by complex changes at subcellular, cellular and extracellular levels in the ventricular myocardium. For all of the gains that conventional treatments for HF have brought to mortality and morbidity, they do not adequately address the loss of cardiomyocyte numbers in the remodeling ventricle. Originally conceived to address this problem, cellular transplantation for HF has already gone through several stages of evolution over the past two decades. Various cell types and delivery routes have been implemented to positive effect in preclinical models of ischemic and nonischemic cardiomyopathy, with pleiotropic benefits observed in terms of myocardial remodeling, systolic and diastolic performance, perfusion, fibrosis, inflammation, metabolism and electrophysiology. To a large extent, these salubrious effects are now attributed to the indirect, paracrine capacity of transplanted stem cells to facilitate endogenous cardiac repair processes. Promising results have also followed in early phase human studies, although these have been relatively modest and somewhat inconsistent. This review details the preclinical and clinical evidence currently available regarding the use of pluripotent stem cells and adult-derived progenitor cells for cardiomyopathy and HF. It outlines the important lessons that have been learned to this point in time, and balances the promise of this exciting field against the key challenges and questions that still need to be addressed at all levels of research, to ensure that cell therapy realizes its full potential by adding to the armamentarium of HF management. PMID:27280304

  2. Cellular oncogenes in neoplasia.

    OpenAIRE

    Chan, V T; McGee, J O

    1987-01-01

    In recent years cellular homologues of many viral oncogenes have been identified. As these genes are partially homologous to viral oncogenes and are activated in some tumour cell lines they are termed "proto-oncogenes". In tumour cell lines proto-oncogenes are activated by either quantitative or qualitative changes in gene structure: activation of these genes was originally thought to be a necessary primary event in carcinogenesis, but activated cellular oncogenes, unlike viral oncogenes, do ...

  3. Cellular Cardiomyoplasty: Clinical Application

    OpenAIRE

    Chachques, J. (J.); Acar, C; J. Herreros; Trainini, J. (Jorge); Prosper, F.; D’Attellis, N. (N.); Fabiani, J. N.; Carpentier, A

    2004-01-01

    Myocardial regeneration can be induced with the implantation of a variety of myogenic and angiogenic cell types. More than 150 patients have been treated with cellular cardiomyoplasty worldwide, 18 patients have been treated by our group. Cellular cardiomyoplasty seems to reduce the size and fibrosis of infarct scars, limit postischemic remodelling, and restore regional myocardial contractility. Techniques for skeletal myoblasts culture and ex vivo expansion using auto...

  4. Software-Defined Cellular Mobile Network Solutions

    Institute of Scientific and Technical Information of China (English)

    Jiandong Li; Peng Liu; Hongyan Li

    2014-01-01

    The emergency relating to software-defined networking (SDN), especially in terms of the prototype associated with OpenFlow, pro-vides new possibilities for innovating on network design. Researchers have started to extend SDN to cellular networks. Such new programmable architecture is beneficial to the evolution of mobile networks and allows operators to provide better services. The typical cellular network comprises radio access network (RAN) and core network (CN); hence, the technique roadmap diverges in two ways. In this paper, we investigate SoftRAN, the latest SDN solution for RAN, and SoftCell and MobileFlow, the latest solu-tions for CN. We also define a series of control functions for CROWD. Unlike in the other literature, we emphasize only software-defined cellular network solutions and specifications in order to provide possible research directions.

  5. A framework for understanding cellular manufacturing systems

    OpenAIRE

    Silva, Sílvio Carmo; Alves, Anabela Carvalho

    2002-01-01

    Many practical benefits, such as superior quality of products and short manufacturing lead times, are usually associated with Cellular Manufacturing. These and other benefits can lead to important competitive advantages of companies. However, to fully achieve these benefits there is a need for an evolution from the traditional concept of CM to the more comprehensive one, which we call Product Oriented Manufacturing. Here systems are dynamically reconfigured for total manufac...

  6. Cellular Automation of Galactic Habitable Zone

    CERN Document Server

    Vukotic, Branislav

    2010-01-01

    We present a preliminary results of our Galactic Habitable Zone (GHZ) 2D probabilistic cellular automata models. The relevant time-scales (emergence of life, it's diversification and evolution influenced with the global risk function) are modeled as the probability matrix elements and are chosen in accordance with the Copernican principle to be well-represented by the data inferred from the Earth's fossil record. With Fermi's paradox as a main boundary condition the resulting histories of astrobiological landscape are discussed.

  7. 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...

  8. The modern theory of biological evolution: an expanded synthesis.

    Science.gov (United States)

    Kutschera, Ulrich; Niklas, Karl J

    2004-06-01

    In 1858, two naturalists, Charles Darwin and Alfred Russel Wallace, independently proposed natural selection as the basic mechanism responsible for the origin of new phenotypic variants and, ultimately, new species. A large body of evidence for this hypothesis was published in Darwin's Origin of Species one year later, the appearance of which provoked other leading scientists like August Weismann to adopt and amplify Darwin's perspective. Weismann's neo-Darwinian theory of evolution was further elaborated, most notably in a series of books by Theodosius Dobzhansky, Ernst Mayr, Julian Huxley and others. In this article we first summarize the history of life on Earth and provide recent evidence demonstrating that Darwin's dilemma (the apparent missing Precambrian record of life) has been resolved. Next, the historical development and structure of the "modern synthesis" is described within the context of the following topics: paleobiology and rates of evolution, mass extinctions and species selection, macroevolution and punctuated equilibrium, sexual reproduction and recombination, sexual selection and altruism, endosymbiosis and eukaryotic cell evolution, evolutionary developmental biology, phenotypic plasticity, epigenetic inheritance and molecular evolution, experimental bacterial evolution, and computer simulations (in silico evolution of digital organisms). In addition, we discuss the expansion of the modern synthesis, embracing all branches of scientific disciplines. It is concluded that the basic tenets of the synthetic theory have survived, but in modified form. These sub-theories require continued elaboration, particularly in light of molecular biology, to answer open-ended questions concerning the mechanisms of evolution in all five kingdoms of life. PMID:15241603

  9. The modern theory of biological evolution: an expanded synthesis

    Science.gov (United States)

    Kutschera, Ulrich; Niklas, Karl J.

    In 1858, two naturalists, Charles Darwin and Alfred Russel Wallace, independently proposed natural selection as the basic mechanism responsible for the origin of new phenotypic variants and, ultimately, new species. A large body of evidence for this hypothesis was published in Darwin's Origin of Species one year later, the appearance of which provoked other leading scientists like August Weismann to adopt and amplify Darwin's perspective. Weismann's neo-Darwinian theory of evolution was further elaborated, most notably in a series of books by Theodosius Dobzhansky, Ernst Mayr, Julian Huxley and others. In this article we first summarize the history of life on Earth and provide recent evidence demonstrating that Darwin's dilemma (the apparent missing Precambrian record of life) has been resolved. Next, the historical development and structure of the ``modern synthesis'' is described within the context of the following topics: paleobiology and rates of evolution, mass extinctions and species selection, macroevolution and punctuated equilibrium, sexual reproduction and recombination, sexual selection and altruism, endosymbiosis and eukaryotic cell evolution, evolutionary developmental biology, phenotypic plasticity, epigenetic inheritance and molecular evolution, experimental bacterial evolution, and computer simulations (in silico evolution of digital organisms). In addition, we discuss the expansion of the modern synthesis, embracing all branches of scientific disciplines. It is concluded that the basic tenets of the synthetic theory have survived, but in modified form. These sub-theories require continued elaboration, particularly in light of molecular biology, to answer open-ended questions concerning the mechanisms of evolution in all five kingdoms of life.

  10. Irregular Cellular Learning Automata.

    Science.gov (United States)

    Esnaashari, Mehdi; Meybodi, Mohammad Reza

    2015-08-01

    Cellular learning automaton (CLA) is a recently introduced model that combines cellular automaton (CA) and learning automaton (LA). The basic idea of CLA is to use LA to adjust the state transition probability of stochastic CA. This model has been used to solve problems in areas such as channel assignment in cellular networks, call admission control, image processing, and very large scale integration placement. In this paper, an extension of CLA called irregular CLA (ICLA) is introduced. This extension is obtained by removing the structure regularity assumption in CLA. Irregularity in the structure of ICLA is needed in some applications, such as computer networks, web mining, and grid computing. The concept of expediency has been introduced for ICLA and then, conditions under which an ICLA becomes expedient are analytically found. PMID:25291810

  11. Architected Cellular Materials

    Science.gov (United States)

    Schaedler, Tobias A.; Carter, William B.

    2016-07-01

    Additive manufacturing enables fabrication of materials with intricate cellular architecture, whereby progress in 3D printing techniques is increasing the possible configurations of voids and solids ad infinitum. Examples are microlattices with graded porosity and truss structures optimized for specific loading conditions. The cellular architecture determines the mechanical properties and density of these materials and can influence a wide range of other properties, e.g., acoustic, thermal, and biological properties. By combining optimized cellular architectures with high-performance metals and ceramics, several lightweight materials that exhibit strength and stiffness previously unachievable at low densities were recently demonstrated. This review introduces the field of architected materials; summarizes the most common fabrication methods, with an emphasis on additive manufacturing; and discusses recent progress in the development of architected materials. The review also discusses important applications, including lightweight structures, energy absorption, metamaterials, thermal management, and bioscaffolds.

  12. Cellular Homeostasis and Aging.

    Science.gov (United States)

    Hartl, F Ulrich

    2016-06-01

    Aging and longevity are controlled by a multiplicity of molecular and cellular signaling events that interface with environmental factors to maintain cellular homeostasis. Modulation of these pathways to extend life span, including insulin-like signaling and the response to dietary restriction, identified the cellular machineries and networks of protein homeostasis (proteostasis) and stress resistance pathways as critical players in the aging process. A decline of proteostasis capacity during aging leads to dysfunction of specific cell types and tissues, rendering the organism susceptible to a range of chronic diseases. This volume of the Annual Review of Biochemistry contains a set of two reviews addressing our current understanding of the molecular mechanisms underlying aging in model organisms and humans. PMID:27050288

  13. 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.

  14. Translating partitioned cellular automata into classical type cellular automata

    OpenAIRE

    Poupet, Victor

    2008-01-01

    Partitioned cellular automata are a variant of cellular automata that was defined in order to make it very simple to create complex automata having strong properties such as number conservation and reversibility (which are often difficult to obtain on cellular automata). In this article we show how a partitioned cellular automaton can be translated into a regular cellular automaton in such a way that these properties are conserved.

  15. Stochastic properties of disturbed Elementary Cellular Automata

    International Nuclear Information System (INIS)

    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)

  16. Genetic Dominance & Cellular Processes

    Science.gov (United States)

    Seager, Robert D.

    2014-01-01

    In learning genetics, many students misunderstand and misinterpret what "dominance" means. Understanding is easier if students realize that dominance is not a mechanism, but rather a consequence of underlying cellular processes. For example, metabolic pathways are often little affected by changes in enzyme concentration. This means that…

  17. Radioactivity of cellular concrete

    International Nuclear Information System (INIS)

    The natural radioactivity of cellular concrete is discussed. Some data on the concentrations of 40K, 226Ra and 232Th in building materials in Poland are given. The results of dose rates measurements in living quarters as well as outside are presented. (A.S.)

  18. The New Cellular Immunology

    Science.gov (United States)

    Claman, Henry N.

    1973-01-01

    Discusses the nature of the immune response and traces many of the discoveries that have led to the present state of knowledge in immunology. The new cellular immunology is directing its efforts toward improving health by proper manipulation of the immune mechanisms of the body. (JR)

  19. Evolution and disease.

    Science.gov (United States)

    Williams, Nigel

    2003-01-01

    A recent meeting highlighted how much Darwinian thinking on natural selection illuminates the background to some major current human diseases and may offer insight into many more. Nigel Williams reports on a field seeking a place in mainstream medical education. PMID:12526752

  20. Constructive neutral evolution: exploring evolutionary theory’s curious disconnect

    Directory of Open Access Journals (Sweden)

    Stoltzfus Arlin

    2012-10-01

    Full Text Available Abstract Constructive neutral evolution (CNE suggests that neutral evolution may follow a stepwise path to extravagance. Whether or not CNE is common, the mere possibility raises provocative questions about causation: in classical neo-Darwinian thinking, selection is the sole source of creativity and direction, the only force that can cause trends or build complex features. However, much of contemporary evolutionary genetics departs from the conception of evolution underlying neo-Darwinism, resulting in a widening gap between what formal models allow, and what the prevailing view of the causes of evolution suggests. In particular, a mutationist conception of evolution as a 2-step origin-fixation process has been a source of theoretical innovation for 40 years, appearing not only in the Neutral Theory, but also in recent breakthroughs in modeling adaptation (the “mutational landscape” model, and in practical software for sequence analysis. In this conception, mutation is not a source of raw materials, but an agent that introduces novelty, while selection is not an agent that shapes features, but a stochastic sieve. This view, which now lays claim to important theoretical, experimental, and practical results, demands our attention. CNE provides a way to explore its most significant implications about the role of variation in evolution. Reviewers Alex Kondrashov, Eugene Koonin and Johann Peter Gogarten reviewed this article.

  1. Cellular bridges: Routes for intercellular communication and cell migration

    OpenAIRE

    Zani, Brett G.; Edelman, Elazer R.

    2010-01-01

    Cell-to-cell communication is the basis of all biology in multicellular organisms, allowing evolution of complex forms and viability in dynamic environments. Though biochemical interactions occur over distances, physical continuity remains the most direct means of cellular interactions. Cellular bridging through thin cytoplasmic channels—plasmodesmata in plants and tunneling nanotubes in animals—creates direct routes for transfer of signals and components, even pathogens, between cells. Recen...

  2. Accelerated evolution of the pituitary adenylate cyclase-activating polypeptide precursor gene during human origin

    DEFF Research Database (Denmark)

    Wang, Yin-Qiu; Qian, Ya-Ping; Yang, Su;

    2005-01-01

    strong functional constraint during the course of evolution. However, through comparative sequence analysis, we demonstrated that the PACAP precursor gene underwent an accelerated evolution in the human lineage since the divergence from chimpanzees, and the amino acid substitution rate in humans is at...... neuropeptide might have originated during human evolution and functioned in the human brain. Our data suggested that the PACAP precursor gene underwent adaptive changes during human origin and may have contributed to the formation of human cognition. Udgivelsesdato: 2005-Jun...... least seven times faster than that in other mammal species resulting from strong Darwinian positive selection. Eleven human-specific amino acid changes were identified in the PACAP precursors, which are conserved from murine to African apes. Protein structural analysis suggested that a putative novel...

  3. Molecular and Cellular Signaling

    CERN Document Server

    Beckerman, Martin

    2005-01-01

    A small number of signaling pathways, no more than a dozen or so, form a control layer that is responsible for all signaling in and between cells of the human body. The signaling proteins belonging to the control layer determine what kinds of cells are made during development and how they function during adult life. Malfunctions in the proteins belonging to the control layer are responsible for a host of human diseases ranging from neurological disorders to cancers. Most drugs target components in the control layer, and difficulties in drug design are intimately related to the architecture of the control layer. Molecular and Cellular Signaling provides an introduction to molecular and cellular signaling in biological systems with an emphasis on the underlying physical principles. The text is aimed at upper-level undergraduates, graduate students and individuals in medicine and pharmacology interested in broadening their understanding of how cells regulate and coordinate their core activities and how diseases ...

  4. Electromagnetic cellular interactions

    Czech Academy of Sciences Publication Activity Database

    Cifra, Michal; Fields, J. S.; Farhadi, A.

    2011-01-01

    Roč. 105, č. 3 (2011), 223-246. ISSN 0079-6107. [36th International Congress of Physiological Sciences (IUPS2009). Kyoto, 27.07.2009-01.08.2009] R&D Projects: GA ČR(CZ) GPP102/10/P454 Institutional research plan: CEZ:AV0Z20670512 Keywords : bioelectric phenomena * cellular biophysics Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.203, year: 2011

  5. Magnetic Cellular Switches

    OpenAIRE

    Overby, Darryl R.; Alenghat, Francis J.; Montoya-Zavala, Martín; Bei, HuCheng; Oh, Philmo; Karavitis, John; Ingber, Donald E.

    2004-01-01

    This paper focuses on the development of magnetic cellular switches to enable magnetic control of intracellular functions in living mammalian cells, including receptor signal transduction and gene transcription. Our approach takes advantage of the mechanosensitivity of adenosine 3′,5′-monophosphate (cAMP) induction and downstream transcription controlled by the cAMP regulatory element (CRE) to engineer gene constructs that optically report gene expression in living cells. We activate transcri...

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

    Directory of Open Access Journals (Sweden)

    Dimitris Iliopoulos

    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.

  7. 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. PMID:24329934

  8. Cellular therapy in Tuberculosis

    Directory of Open Access Journals (Sweden)

    Shreemanta K. Parida

    2015-03-01

    Full Text Available Cellular therapy now offer promise of potential adjunct therapeutic options for treatment of drug-resistant tuberculosis (TB. We review here the role of Mesenchymal stromal cells, (MSCs, as well as other immune effector cells in the therapy of infectious diseases with a focus on TB. MSCs represent a population of tissue-resident non-hematopoietic adult progenitor cells which home into injured tissues increase the proliferative potential of broncho-alveolar stem cells and restore lung epithelium. MSCs have been shown to be immune-modulatory and anti-inflammatory mediated via cell-cell contacts as well as soluble factors. We discuss the functional profile of MSCs and their potential use for adjunct cellular therapy of multi-drug resistant TB, with the aim of limiting tissue damage, and to convert unproductive inflammatory responses into effective anti-pathogen directed immune responses. Adjunct cellular therapy could potentially offer salvage therapy options for patients with drug-resistant TB, increase clinically relevant anti-M.tuberculosis directed immune responses and possibly shorten the duration of anti-TB therapy.

  9. Cellular therapy in tuberculosis.

    Science.gov (United States)

    Parida, Shreemanta K; Madansein, Rajhmun; Singh, Nalini; Padayatchi, Nesri; Master, Iqbal; Naidu, Kantharuben; Zumla, Alimuddin; Maeurer, Markus

    2015-03-01

    Cellular therapy now offer promise of potential adjunct therapeutic options for treatment of drug-resistant tuberculosis (TB). We review here the role of Mesenchymal stromal cells, (MSCs), as well as other immune effector cells in the therapy of infectious diseases with a focus on TB. MSCs represent a population of tissue-resident non-hematopoietic adult progenitor cells which home into injured tissues increase the proliferative potential of broncho-alveolar stem cells and restore lung epithelium. MSCs have been shown to be immune-modulatory and anti-inflammatory mediated via cell-cell contacts as well as soluble factors. We discuss the functional profile of MSCs and their potential use for adjunct cellular therapy of multi-drug resistant TB, with the aim of limiting tissue damage, and to convert unproductive inflammatory responses into effective anti-pathogen directed immune responses. Adjunct cellular therapy could potentially offer salvage therapy options for patients with drug-resistant TB, increase clinically relevant anti-M.tuberculosis directed immune responses and possibly shorten the duration of anti-TB therapy. PMID:25809753

  10. Quantum cellular automata

    Science.gov (United States)

    Porod, Wolfgang; Lent, Craig S.; Bernstein, Gary H.

    1994-06-01

    The Notre Dame group has developed a new paradigm for ultra-dense and ultra-fast information processing in nanoelectronic systems. These Quantum Cellular Automata (QCA's) are the first concrete proposal for a technology based on arrays of coupled quantum dots. The basic building block of these cellular arrays is the Notre Dame Logic Cell, as it has been called in the literature. The phenomenon of Coulomb exclusion, which is a synergistic interplay of quantum confinement and Coulomb interaction, leads to a bistable behavior of each cell which makes possible their use in large-scale cellular arrays. The physical interaction between neighboring cells has been exploited to implement logic functions. New functionality may be achieved in this fashion, and the Notre Dame group invented a versatile majority logic gate. In a series of papers, the feasibility of QCA wires, wire crossing, inverters, and Boolean logic gates was demonstrated. A major finding is that all logic functions may be integrated in a hierarchial fashion which allows the design of complicated QCA structures. The most complicated system which was simulated to date is a one-bit full adder consisting of some 200 cells. In addition to exploring these new concepts, efforts are under way to physically realize such structures both in semiconductor and metal systems. Extensive modeling work of semiconductor quantum dot structures has helped identify optimum design parameters for QCA experimental implementations.

  11. Evolution of differentiated expression patterns in digital organisms

    CERN Document Server

    Ofria, C A; Collier, T C; Hsu, G K; Ofria, Charles; Adami, Christoph; Collier, Travis C.; Hsu, Grace K.

    2000-01-01

    We investigate the evolutionary processes behind the development andoptimization of multiple threads of execution in digital organisms using theavida platform, a software package that implements Darwinian evolution onpopulations of self-replicating computer programs. The system is seeded with alinearly executed ancestor capable only of reproducing its own genome, whereasits underlying language has the capacity for multiple threads of execution(i.e., simultaneous expression of sections of the genome.) We witness theevolution to multi-threaded organisms and track the development of distinctexpression patterns. Additionally, we examine both the evolvability ofmulti-threaded organisms and the level of thread differentiation as a functionof environmental complexity, and find that differentiation is more pronouncedin complex environments.

  12. Extremal Optimization: Methods Derived from Co-Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Boettcher, S.; Percus, A.G.

    1999-07-13

    We describe a general-purpose method for finding high-quality solutions to hard optimization problems, inspired by self-organized critical models of co-evolution such as the Bak-Sneppen model. The method, called Extremal Optimization, successively eliminates extremely undesirable components of sub-optimal solutions, rather than ''breeding'' better components. In contrast to Genetic Algorithms which operate on an entire ''gene-pool'' of possible solutions, Extremal Optimization improves on a single candidate solution by treating each of its components as species co-evolving according to Darwinian principles. Unlike Simulated Annealing, its non-equilibrium approach effects an algorithm requiring few parameters to tune. With only one adjustable parameter, its performance proves competitive with, and often superior to, more elaborate stochastic optimization procedures. We demonstrate it here on two classic hard optimization problems: graph partitioning and the traveling salesman problem.

  13. 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

  14. Cellular and molecular introduction to brain development.

    Science.gov (United States)

    Jiang, Xiangning; Nardelli, Jeannette

    2016-08-01

    Advances in the study of brain development over the last decades, especially recent findings regarding the evolutionary expansion of the human neocortex, and large-scale analyses of the proteome/transcriptome in the human brain, have offered novel insights into the molecular mechanisms guiding neural maturation, and the pathophysiology of multiple forms of neurological disorders. As a preamble to reviews of this issue, we provide an overview of the cellular, molecular and genetic bases of brain development with an emphasis on the major mechanisms associated with landmarks of normal neural development in the embryonic stage and early postnatal life, including neural stem/progenitor cell proliferation, cortical neuronal migration, evolution and folding of the cerebral cortex, synaptogenesis and neural circuit development, gliogenesis and myelination. We will only briefly depict developmental disorders that result from perturbations of these cellular or molecular mechanisms, and the most common perinatal brain injuries that could disturb normal brain development. PMID:26184894

  15. Quantum features of natural cellular automata

    Science.gov (United States)

    Elze, Hans-Thomas

    2016-03-01

    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.

  16. SELF-ORGANIZED CRITICALITY AND CELLULAR AUTOMATA

    Energy Technology Data Exchange (ETDEWEB)

    CREUTZ,M.

    2007-01-01

    Cellular automata provide a fascinating class of dynamical systems based on very simple rules of evolution yet capable of displaying highly complex behavior. These include simplified models for many phenomena seen in nature. Among other things, they provide insight into self-organized criticality, wherein dissipative systems naturally drive themselves to a critical state with important phenomena occurring over a wide range of length and the scales. This article begins with an overview of self-organized criticality. This is followed by a discussion of a few examples of simple cellular automaton systems, some of which may exhibit critical behavior. Finally, some of the fascinating exact mathematical properties of the Bak-Tang-Wiesenfeld sand-pile model [1] are discussed.

  17. Quantum features of natural cellular automata

    CERN Document Server

    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 Schroedinger 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 $l\\rightarrow 0$ 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...

  18. Is Lamarckian evolution relevant to medicine?

    Directory of Open Access Journals (Sweden)

    Handel Adam E

    2010-05-01

    Full Text Available Abstract Background 200 years have now passed since Darwin was born and scientists around the world are celebrating this important anniversary of the birth of an evolutionary visionary. However, the theories of his colleague Lamarck are treated with considerably less acclaim. These theories centre on the tendency for complexity to increase in organisms over time and the direct transmission of phenotypic traits from parents to offspring. Discussion Lamarckian concepts, long thought of no relevance to modern evolutionary theory, are enjoying a quiet resurgence with the increasing complexity of epigenetic theories of inheritance. There is evidence that epigenetic alterations, including DNA methylation and histone modifications, are transmitted transgenerationally, thus providing a potential mechanism for environmental influences to be passed from parents to offspring: Lamarckian evolution. Furthermore, evidence is accumulating that epigenetics plays an important role in many common medical conditions. Summary Epigenetics allows the peaceful co-existence of Darwinian and Lamarckian evolution. Further efforts should be exerted on studying the mechanisms by which this occurs so that public health measures can be undertaken to reverse or prevent epigenetic changes important in disease susceptibility. Perhaps in 2059 we will be celebrating the anniversary of both Darwin and Lamarck.

  19. Failover in cellular automata

    CERN Document Server

    Kumar, Shailesh

    2010-01-01

    A cellular automata (CA) configuration is constructed that exhibits emergent failover. The configuration is based on standard Game of Life rules. Gliders and glider-guns form the core messaging structure in the configuration. The blinker is represented as the basic computational unit, and it is shown how it can be recreated in case of a failure. Stateless failover using primary-backup mechanism is demonstrated. The details of the CA components used in the configuration and its working are described, and a simulation of the complete configuration is also presented.

  20. Cellular-scale hydrodynamics

    DEFF Research Database (Denmark)

    Abkarian, Manouk; Faivre, Magalie; Horton, Renita; Smistrup, Kristian; Best-Popescu, Catherine A; Stone, Howard A.

    2008-01-01

    Microfluidic tools are providing many new insights into the chemical, physical and physicochemical responses of cells. Both suspension-level and single-cell measurements have been studied. We review our studies of these kinds of problems for red blood cells with particular focus on the shapes of ...... mechanical effects on suspended cells can be studied systematically in small devices, and how these features can be exploited to develop methods for characterizing physicochemical responses and possibly for the diagnosis of cellular-scale changes to environmental factors....

  1. Cellular mechanics and motility

    Science.gov (United States)

    Hénon, Sylvie; Sykes, Cécile

    2015-10-01

    The term motility defines the movement of a living organism. One widely known example is the motility of sperm cells, or the one of flagellar bacteria. The propulsive element of such organisms is a cilium(or flagellum) that beats. Although cells in our tissues do not have a flagellum in general, they are still able to move, as we will discover in this chapter. In fact, in both cases of movement, with or without a flagellum, cell motility is due to a dynamic re-arrangement of polymers inside the cell. Let us first have a closer look at the propulsion mechanism in the case of a flagellum or a cilium, which is the best known, but also the simplest, and which will help us to define the hydrodynamic general conditions of cell movement. A flagellum is sustained by cellular polymers arranged in semi-flexible bundles and flagellar beating generates cell displacement. These polymers or filaments are part of the cellular skeleton, or "cytoskeleton", which is, in this case, external to the cellular main body of the organism. In fact, bacteria move in a hydrodynamic regime in which viscosity dominates over inertia. The system is thus in a hydrodynamic regime of low Reynolds number (Box 5.1), which is nearly exclusively the case in all cell movements. Bacteria and their propulsion mode by flagella beating are our unicellular ancestors 3.5 billion years ago. Since then, we have evolved to form pluricellular organisms. However, to keep the ability of displacement, to heal our wounds for example, our cells lost their flagellum, since it was not optimal in a dense cell environment: cells are too close to each other to leave enough space for the flagella to accomplish propulsion. The cytoskeleton thus developed inside the cell body to ensure cell shape changes and movement, and also mechanical strength within a tissue. The cytoskeleton of our cells, like the polymers or filaments that sustain the flagellum, is also composed of semi-flexible filaments arranged in bundles, and also in

  2. Radiolabelled Cellular Blood Elements

    International Nuclear Information System (INIS)

    This volume contains the abstracts of the 5th International Symposion on Radiolabelling of Cellular Blood Elements to be held in Vienna, Austria, September 10-14, 1989. The Meeting is the fifth in a series of meetings designed to discuss the basics and clinical application of radiolabelling techniques. In these days, beside the search for new labelling agents and extending the knowledge in clinical use, the use of monoclonal antibodies is a big new challenge. All reviewed contributions that have been accepted for presentation are contained in this volume. (authors) 58 of them are of INIS scope

  3. Propagation Mechanism of Cylindrical Cellular Detonation

    Science.gov (United States)

    Han, Wen-Hu; Wang, Cheng; Ning, Jian-Guo

    2012-10-01

    We investigate the evolution of cylindrical cellular detonation with different instabilities. The numerical results show that with decreasing initial temperature, detonation becomes more unstable and the cells of the cylindrical detonation tend to be irregular. For stable detonation, a divergence of cylindrical detonation cells is formed eventually due to detonation instability resulting from a curved detonation front. For mildly unstable detonation, local overdriven detonation occurs. The detonation cell diverges and its size decreases. For highly unstable detonation, locally driven detonation is more obvious and the front is highly wrinkled. As a result, the diverging cylindrical detonation cell becomes highly irregular.

  4. Quantumness of discrete Hamiltonian cellular automata

    Directory of Open Access Journals (Sweden)

    Elze Hans-Thomas

    2014-01-01

    Full Text Available We summarize a recent study of discrete (integer-valued Hamiltonian cellular automata (CA showing that their dynamics can only be consistently defined, if it is linear in the same sense as unitary evolution described by the Schrödinger equation. This allows to construct an invertible map between such CA and continuous quantum mechanical models, which incorporate a fundamental scale. Presently, we emphasize general aspects of these findings, the construction of admissible CA observables, and the existence of solutions of the modified dispersion relation for stationary states.

  5. The Evolution of Multicellular Plants and Animals.

    Science.gov (United States)

    Valentine, James W.

    1978-01-01

    Traces the evolution of unicellular organisms to the multi-cellular plants and animals in existence today. Major events are depicted in a geologic timetable. Organisms, extinct and recent, are classified by taxonomic group. (MA)

  6. Modeling the topological organization of cellular processes.

    Science.gov (United States)

    Giavitto, Jean-Louis; Michel, Olivier

    2003-07-01

    The cell as a dynamical system presents the characteristics of having a dynamical structure. That is, the exact phase space of the system cannot be fixed before the evolution and integrative cell models must state the evolution of the structure jointly with the evolution of the cell state. This kind of dynamical systems is very challenging to model and simulate. New programming concepts must be developed to ease their modeling and simulation. In this context, the goal of the MGS project is to develop an experimental programming language dedicated to the simulation of this kind of systems. MGS proposes a unified view on several computational mechanisms (CHAM, Lindenmayer systems, Paun systems, cellular automata) enabling the specification of spatially localized computations on heterogeneous entities. The evolution of a dynamical structure is handled through the concept of transformation which relies on the topological organization of the system components. An example based on the modeling of spatially distributed biochemical networks is used to illustrate how these notions can be used to model the spatial and temporal organization of intracellular processes. PMID:12915272

  7. Simulation of Dynamic Recrystallization Using Cellular Automaton Method

    Institute of Scientific and Technical Information of China (English)

    XIAO Hong; XIE Hong-biao; YAN Yan-hong; Jun YANAGIMOTO

    2004-01-01

    A new modeling approach that couples fundamental metallurgical principles of dynamical recrystallization with the cellular automaton method was developed to simulate the microstructural evolution linking with the plastic flow behavior during thermomechanical processing. The driving force for the nucleation and growth of dynamically recrystallized grain is the volume free energy due to the stored dislocation density of a deformation matrix. The growth terminates the impingement. The model is capable of simulating kinetics, microstructure and texture evolution during recrystallization. The predictions of microstructural evolution agree with the experimental results.

  8. Integrated cellular systems

    Science.gov (United States)

    Harper, Jason C.

    The generation of new three-dimensional (3D) matrices that enable integration of biomolecular components and whole cells into device architectures, without adversely altering their morphology or activity, continues to be an expanding and challenging field of research. This research is driven by the promise that encapsulated biomolecules and cells can significantly impact areas as diverse as biocatalysis, controlled delivery of therapeutics, environmental and industrial process monitoring, early warning of warfare agents, bioelectronics, photonics, smart prosthetics, advanced physiological sensors, portable medical diagnostic devices, and tissue/organ replacement. This work focuses on the development of a fundamental understanding of the biochemical and nanomaterial mechanisms that govern the cell directed assembly and integration process. It was shown that this integration process relies on the ability of cells to actively develop a pH gradient in response to evaporation induced osmotic stress, which catalyzes silica condensation within a thin 3D volume surrounding the cells, creating a functional bio/nano interface. The mechanism responsible for introducing functional foreign membrane-bound proteins via proteoliposome addition to the silica-lipid-cell matrix was also determined. Utilizing this new understanding, 3D cellular immobilization capabilities were extended using sol-gel matrices endowed with glycerol, trehalose, and media components. The effects of these additives, and the metabolic phase of encapsulated S. cerivisiase cells, on long-term viability and the rate of inducible gene expression was studied. This enabled the entrapment of cells within a novel microfluidic platform capable of simultaneous colorimetric, fluorescent, and electrochemical detection of a single analyte, significantly improving confidence in the biosensor output. As a complementary approach, multiphoton protein lithography was utilized to engineer 3D protein matrices in which to

  9. Multiuser Cellular Network

    CERN Document Server

    Bao, Yi; Chen, Ming

    2011-01-01

    Modern radio communication is faced with a problem about how to distribute restricted frequency to users in a certain space. Since our task is to minimize the number of repeaters, a natural idea is enlarging coverage area. However, coverage has restrictions. First, service area has to be divided economically as repeater's coverage is limited. In this paper, our fundamental method is to adopt seamless cellular network division. Second, underlying physics content in frequency distribution problem is interference between two close frequencies. Consequently, we choose a proper frequency width of 0.1MHz and a relevantly reliable setting to apply one frequency several times. We make a few general assumptions to simplify real situation. For instance, immobile users yield to homogenous distribution; repeaters can receive and transmit information in any given frequency in duplex operation; coverage is mainly decided by antenna height. Two models are built up to solve 1000 users and 10000 users situations respectively....

  10. Modeling and cellular studies

    International Nuclear Information System (INIS)

    Testing the applicability of mathematical models with carefully designed experiments is a powerful tool in the investigations of the effects of ionizing radiation on cells. The modeling and cellular studies complement each other, for modeling provides guidance for designing critical experiments which must provide definitive results, while the experiments themselves provide new input to the model. Based on previous experimental results the model for the accumulation of damage in Chlamydomonas reinhardi has been extended to include various multiple two-event combinations. Split dose survival experiments have shown that models tested to date predict most but not all the observed behavior. Stationary-phase mammalian cells, required for tests of other aspects of the model, have been shown to be at different points in the cell cycle depending on how they were forced to stop proliferating. These cultures also demonstrate different capacities for repair of sublethal radiation damage

  11. Engineering Cellular Metabolism

    DEFF Research Database (Denmark)

    Nielsen, Jens; Keasling, Jay

    2016-01-01

    Metabolic engineering is the science of rewiring the metabolism of cells to enhance production of native metabolites or to endow cells with the ability to produce new products. The potential applications of such efforts are wide ranging, including the generation of fuels, chemicals, foods, feeds......, and pharmaceuticals. However, making cells into efficient factories is challenging because cells have evolved robust metabolic networks with hard-wired, tightly regulated lines of communication between molecular pathways that resist efforts to divert resources. Here, we will review the current status and challenges...... of metabolic engineering and will discuss how new technologies can enable metabolic engineering to be scaled up to the industrial level, either by cutting off the lines of control for endogenous metabolism or by infiltrating the system with disruptive, heterologous pathways that overcome cellular regulation....

  12. LA SELECCIÓN NATURAL Y LOS CULTIVOS TRANSGÉNICOS: ¿UN HIATO DARWINISTA? Natural Selection and Transgenic Crops: A Darwinian Hiatus?

    Directory of Open Access Journals (Sweden)

    ALEJANDRO CHAPARRO-GIRALDO

    . En el contexto de la evidencia analizada, parecería que los cultivos transgénicos no escapan a la selección natural darwinista, sin embargo es muy temprano en términos evolutivos para llegar a una conclusión sobre este asunto.In December 2008, 125 million hectares of transgenic varieties of soybean, corn, cotton and canola, were reported planted in 23 countries on five continents. These varieties were transformed with genes of prokaryote origin, rendering them resistant to lepidopteran insects attack or toleratant to commercial herbicides. Since the beginning of genetic engineering, the question whether mass release of these crops in agroecosystems, can cause either negative environmental effects in the medium term or evolutionary effects in the long term, has been raised. One way of analyzing this problem is to consider whether they can escape Darwinian natural selection, because foreign genes have been introduced through human manipulation. To this end, I study the available literature on gene flow from modified crops to their wild closely related relatives. There is empirical evidence of hybridization between improved materials, by both conventional methods (hybridization, backcross, selections and biotechnological (transfer of foreign genes, and closely related wild relatives. In any case, the effects of these hybrids depend on the interaction between the transferred gene and the wild relative, the particular ecosystem in which it occurs. The biggest environmental and evolutionary impact is the result of introgression of a transgene in the wild relative, a process that involves stabilization of the transgene in the host genome, as a result of successive generations of hybridization and backcrossing. The introgression depends more upon the nature of the gene and its localization in the donnor s genome, than on the mechanism of introduction. No negative effects on the genetic diversity of species genetically modified, have been reported, neither on the

  13. Darwinian psychology, old and new.

    Science.gov (United States)

    Hampton, Simon

    2005-01-01

    Many senior American and British psychologists between c1890 and c1925 were engaged in an attempt to settle on a unified definition of the term "instinct" as a psychological construct. Whilst this enterprise failed, some of its basic concepts underpin today's project of evolutionary psychology. This claim is substantiated by an analysis of the similarities between William McDougall's "Social Psychology" (1908), in which he articulated his theory of instincts, and John Tooby's and Leda Cosmides' "The Psychological Foundations of Culture" (1992). It is argued that Tooby's and Cosmides' approach faces similar problems as were faced by McDougall's theory of instincts. PMID:19244679

  14. Forced Evolution in Silico by Artificial Transposons and their Genetic Operators: The John Muir Ant Problem

    CERN Document Server

    Spirov, Alexander V; Zamdborg, Leonid; Merelo, Juan J; Levchenko, Vladimir F

    2009-01-01

    Modern evolutionary computation utilizes heuristic optimizations based upon concepts borrowed from the Darwinian theory of natural selection. We believe that a vital direction in this field must be algorithms that model the activity of genomic parasites, such as transposons, in biological evolution. This publication is our first step in the direction of developing a minimal assortment of algorithms that simulate the role of genomic parasites. Specifically, we started in the domain of genetic algorithms (GA) and selected the Artificial Ant Problem as a test case. We define these artificial transposons as a fragment of an ant's code that possesses properties that cause it to stand apart from the rest. We concluded that artificial transposons, analogous to real transposons, are truly capable of acting as intelligent mutators that adapt in response to an evolutionary problem in the course of co-evolution with their hosts.

  15. The rule of declining adaptability in microbial evolution experiments

    Directory of Open Access Journals (Sweden)

    Alejandro eCouce

    2015-03-01

    Full Text Available 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 this possibilities in the light of the various theories of adaptation that have been proposed and delineate future directions of research.

  16. The State of Cellular Probes

    OpenAIRE

    Yim, Youngbin

    2003-01-01

    Cellular probe technology is one of several potentially promising technologies for obtaining accurate travel time information. In 1996, the Federal Communications Commission (FCC) mandated E911 requirements that cellular location be provided when 911 emergency calls come in to emergency management authorities. The E911 requirements allow 50 -300 meters from the emergency call location, depending on the type of cellular phone technology used and whether handset-based or network-based solutions...

  17. Never-ageing cellular senescence

    OpenAIRE

    Ogrunc, Müge; d’Adda di Fagagna, Fabrizio

    2011-01-01

    Cellular senescence was historically discovered as a form of cellular ageing of in vitro cultured cells. It has been under the spotlight following the evidence of oncogene-induced senescence in vivo and its role as a potent tumour suppressor mechanism. Presently, a PubMed search using keywords ‘cellular senescence and cancer’ reveals 8398 number of references (by April 2011) showing that while our knowledge of senescence keeps expanding, the complexity of the phenomenon keeps us – researchers...

  18. A general theory of evolution based on energy efficiency: its implications for diseases.

    Science.gov (United States)

    Yun, Anthony J; Lee, Patrick Y; Doux, John D; Conley, Buford R

    2006-01-01

    We propose a general theory of evolution based on energy efficiency. Life represents an emergent property of energy. The earth receives energy from cosmic sources such as the sun. Biologic life can be characterized by the conversion of available energy into complex systems. Direct energy converters such as photosynthetic microorganisms and plants transform light energy into high-energy phosphate bonds that fuel biochemical work. Indirect converters such as herbivores and carnivores predominantly feed off the food chain supplied by these direct converters. Improving energy efficiency confers competitive advantage in the contest among organisms for energy. We introduce a term, return on energy (ROE), as a measure of energy efficiency. We define ROE as a ratio of the amount of energy acquired by a system to the amount of energy consumed to generate that gain. Life-death cycling represents a tactic to sample the environment for innovations that allow increases in ROE to develop over generations rather than an individual lifespan. However, the variation-selection strategem of Darwinian evolution may define a particular tactic rather than an overarching biological paradigm. A theory of evolution based on competition for energy and driven by improvements in ROE both encompasses prior notions of evolution and portends post-Darwinian mechanisms. Such processes may involve the exchange of non-genetic traits that improve ROE, as exemplified by cognitive adaptations or memes. Under these circumstances, indefinite persistence may become favored over life-death cycling, as increases in ROE may then occur more efficiently within a single lifespan rather than over multiple generations. The key to this transition may involve novel methods to address the promotion of health and cognitive plasticity. We describe the implications of this theory for human diseases. PMID:16122878

  19. Active Cellular Nematics

    Science.gov (United States)

    Duclos, Guillaume; Erlenkaemper, Christoph; Garcia, Simon; Yevick, Hannah; Joanny, Jean-François; Silberzan, Pascal; Biology inspired physics at mesoscales Team; Physical approach of biological problems Team

    We study the emergence of a nematic order in a two-dimensional tissue of apolar elongated fibroblast cells. Initially, these cells are very motile and the monolayer is characterized by giant density fluctuations, a signature of far-from-equilibrium systems. As the cell density increases because of proliferation, the cells align with each other forming large perfectly oriented domains while the cellular movements slow down and eventually freeze. Therefore topological defects characteristic of nematic phases remain trapped at long times, preventing the development of infinite domains. By analogy with classical non-active nematics, we have investigated the role of boundaries and we have shown that cells confined in stripes of width smaller than typically 500 µm are perfectly aligned in the stripe direction. Experiments performed in cross-shaped patterns show that both the number of cells and the degree of alignment impact the final orientation. Reference: Duclos G., Garcia S., Yevick H.G. and Silberzan P., ''Perfect nematic order in confined monolayers of spindle-shaped cells'', Soft Matter, 10, 14, 2014

  20. 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...

  1. Speculations on the early course of evolution

    OpenAIRE

    Darnell, J E; Doolittle, W F

    1986-01-01

    The proposal that RNA preceded DNA in evolution is more than 15 years old. In light of recent studies on RNA processing (including protein-free reactions), present knowledge about eukaryotic gene structure, and studies comparing ribosomal RNA sequences, we propose a train of events for precellular and early cellular evolution.

  2. Models of protocellular structures, functions and evolution

    Science.gov (United States)

    Pohorille, Andrew; New, Michael H.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The central step in the origin of life was the emergence of organized structures from organic molecules available on the early earth. These predecessors to modern cells, called 'proto-cells,' were simple, membrane bounded structures able to maintain themselves, grow, divide, and evolve. Since there is no fossil record of these earliest of life forms, it is a scientific challenge to discover plausible mechanisms for how these entities formed and functioned. To meet this challenge, it is essential to create laboratory models of protocells that capture the main attributes associated with living systems, while remaining consistent with known, or inferred, protobiological conditions. This report provides an overview of a project which has focused on protocellular metabolism and the coupling of metabolism to energy transduction. We have assumed that the emergence of systems endowed with genomes and capable of Darwinian evolution was preceded by a pre-genomic phase, in which protocells functioned and evolved using mostly proteins, without self-replicating nucleic acids such as RNA.

  3. Evolution of evolvability in gene regulatory networks.

    Directory of Open Access Journals (Sweden)

    Anton Crombach

    Full Text Available Gene regulatory networks are perhaps the most important organizational level in the cell where signals from the cell state and the outside environment are integrated in terms of activation and inhibition of genes. For the last decade, the study of such networks has been fueled by large-scale experiments and renewed attention from the theoretical field. Different models have been proposed to, for instance, investigate expression dynamics, explain the network topology we observe in bacteria and yeast, and for the analysis of evolvability and robustness of such networks. Yet how these gene regulatory networks evolve and become evolvable remains an open question. An individual-oriented evolutionary model is used to shed light on this matter. Each individual has a genome from which its gene regulatory network is derived. Mutations, such as gene duplications and deletions, alter the genome, while the resulting network determines the gene expression pattern and hence fitness. With this protocol we let a population of individuals evolve under Darwinian selection in an environment that changes through time. Our work demonstrates that long-term evolution of complex gene regulatory networks in a changing environment can lead to a striking increase in the efficiency of generating beneficial mutations. We show that the population evolves towards genotype-phenotype mappings that allow for an orchestrated network-wide change in the gene expression pattern, requiring only a few specific gene indels. The genes involved are hubs of the networks, or directly influencing the hubs. Moreover, throughout the evolutionary trajectory the networks maintain their mutational robustness. In other words, evolution in an alternating environment leads to a network that is sensitive to a small class of beneficial mutations, while the majority of mutations remain neutral: an example of evolution of evolvability.

  4. The ancient Virus World and evolution of cells

    OpenAIRE

    Dolja Valerian V; Senkevich Tatiana G; Koonin Eugene V

    2006-01-01

    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 ind...

  5. Evolution of cooperation in Axelrod tournament using cellular automata

    Science.gov (United States)

    Schimit, P. H. T.; Santos, B. O.; Soares, C. A.

    2015-11-01

    Results of the Axelrod Tournament were published in 1981, and since then, evolutionary game theory emerged as an idea for understanding relations, like conflict and cooperation, between rational decision-makers. Robert Axelrod organized it as a round-robin tournament where strategies for iterated Prisoner's Dilemma were faced in a sequence of two players game. Here, we attempt to simulate the strategies submitted to the tournament in a multi-agent context, where individuals play a two-player game with their neighbors. Each individual has one of the strategies, and it plays the Prisoner's Dilemma with its neighbors. According to actions chosen (cooperate or defect), points of life are subtracted from their profiles. When an individual dies, some fitness functions are defined to choose the most successful strategy which the new individual will copy. Although tit-for-tat was the best strategy, on average, in the tournament, in our evolutionary multi-agent context, it has not been successful.

  6. Evolution of Cellular Inclusions in Bietti’s Crystalline Dystrophy

    OpenAIRE

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

    2010-01-01

    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 ultrastruct...

  7. 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

  8. 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,...

  9. Protein evolution on a human signaling network

    OpenAIRE

    Purisima Enrico O; Cui Qinghua; Wang Edwin

    2009-01-01

    Abstract Background The architectural structure of cellular networks provides a framework for innovations as well as constraints for protein evolution. This issue has previously been studied extensively by analyzing protein interaction networks. However, it is unclear how signaling networks influence and constrain protein evolution and conversely, how protein evolution modifies and shapes the functional consequences of signaling networks. In this study, we constructed a human signaling networ...

  10. Cellular Automaton Model for Immunology of Tumor Growth

    CERN Document Server

    Voitikova, M

    1998-01-01

    The stochastic discrete space-time model of an immune response on tumor spreading in a two-dimensional square lattice has been developed. The immunity-tumor interactions are described at the cellular level and then transferred into the setting of cellular automata (CA). The multistate CA model for system, in which all statesoflattice sites, composing of both immune and tumor cells populations, are the functions of the states of the 12 nearest neighbors. The CA model incorporates the essential featuresof the immunity-tumor system. Three regimes of neoplastic evolution including metastatic tumor growth and screen effect by inactive immune cells surrounding a tumor have been predicted.

  11. From cellular to tissue scales by asymptotic limits of thermostatted kinetic models

    Science.gov (United States)

    Bianca, Carlo; Dogbe, Christian; Lemarchand, Annie

    2016-02-01

    Tumor growth strictly depends on the interactions occurring at the cellular scale. In order to obtain the linking between the dynamics described at tissue and cellular scales, asymptotic methods have been employed, consisting in deriving tissue equations by suitable limits of mesoscopic models. In this paper, the evolution at the cellular scale is described by thermostatted kinetic theory that include conservative, nonconservative (proliferation, destruction and mutations), stochastic terms, and the role of external agents. The dynamics at the tissue scale (cell-density evolution) is obtained by performing a low-field scaling and considering the related convergence of the rescaled framework when the scaling parameter goes to zero.

  12. Evolution and History in a new "Mathematical SETI" model

    Science.gov (United States)

    Maccone, Claudio

    2014-01-01

    In a recent paper (Maccone, 2011 [15]) and in a recent book (Maccone, 2012 [17]), this author proposed a new mathematical model capable of merging SETI and Darwinian Evolution into a single mathematical scheme. This model is based on exponentials and lognormal probability distributions, called "b-lognormals" if they start at any positive time b ("birth") larger than zero. Indeed: Darwinian evolution theory may be regarded as a part of SETI theory in that the factor fl in the Drake equation represents the fraction of planets suitable for life on which life actually arose, as it happened on Earth. In 2008 (Maccone, 2008 [9]) this author firstly provided a statistical generalization of the Drake equation where the number N of communicating ET civilizations in the Galaxy was shown to follow the lognormal probability distribution. This fact is a consequence of the Central Limit Theorem (CLT) of Statistics, stating that the product of a number of independent random variables whose probability densities are unknown and independent of each other approached the lognormal distribution if the number of factors is increased at will, i.e. it approaches infinity. Also, in Maccone (2011 [15]), it was shown that the exponential growth of the number of species typical of Darwinian Evolution may be regarded as the geometric locus of the peaks of a one-parameter family of b-lognormal distributions constrained between the time axis and the exponential growth curve. This was a brand-new result. And one more new and far-reaching idea was to define Darwinian Evolution as a particular realization of a stochastic process called Geometric Brownian Motion (GBM) having the above exponential as its own mean value curve. The b-lognormals may be also be interpreted as the lifespan of any living being, let it be a cell, or an animal, a plant, a human, or even the historic lifetime of any civilization. In Maccone, (2012 [17, Chapters 6, 7, 8 and 11]), as well as in the present paper, we give

  13. Actual problems of cellular cardiomyoplasty

    Directory of Open Access Journals (Sweden)

    Bulat Kaupov

    2010-04-01

    Full Text Available The paper provides review of cellular technologies used incardiology, describes types of cellular preparations depending onsources of cells and types of compounding cells. The generalmechanisms of therapies with stem cells applications are described.Use of cellular preparations for treatment of cardiovascular diseasesand is improvement of the forecast at patients with heartinsufficiency of various genesis is considered as alternative topractice with organ transplantations. Efforts of biotechnologicallaboratories are directed on search of optimum population of cellsfor application in cardiology and studying of mechanisms andfactors regulating function of cardiac stem cells.

  14. 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.

  15. Particles and Patterns in Cellular Automata

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    Afiqah, K. N.; Mahayuddin, Z. R.

    2016-02-01

    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.

  17. Origami interleaved tube cellular materials

    International Nuclear Information System (INIS)

    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)

  18. Engineering Cellular Photocomposite Materials Using Convective Assembly

    Directory of Open Access Journals (Sweden)

    Orlin D. Velev

    2013-05-01

    Full Text Available Fabricating industrial-scale photoreactive composite materials containing living cells, requires a deposition strategy that unifies colloid science and cell biology. Convective assembly can rapidly deposit suspended particles, including whole cells and waterborne latex polymer particles into thin (<10 µm thick, organized films with engineered adhesion, composition, thickness, and particle packing. These highly ordered composites can stabilize the diverse functions of photosynthetic cells for use as biophotoabsorbers, as artificial leaves for hydrogen or oxygen evolution, carbon dioxide assimilation, and add self-cleaning capabilities for releasing or digesting surface contaminants. This paper reviews the non-biological convective assembly literature, with an emphasis on how the method can be modified to deposit living cells starting from a batch process to its current state as a continuous process capable of fabricating larger multi-layer biocomposite coatings from diverse particle suspensions. Further development of this method will help solve the challenges of engineering multi-layered cellular photocomposite materials with high reactivity, stability, and robustness by clarifying how process, substrate, and particle parameters affect coating microstructure. We also describe how these methods can be used to selectively immobilize photosynthetic cells to create biomimetic leaves and compare these biocomposite coatings to other cellular encapsulation systems.

  19. Cellular mechanisms during vascular development

    OpenAIRE

    Blum, Yannick

    2012-01-01

    The vascular system is an essential organ in vertebrate animals and provides the organism with enough oxygen and nutrients. It is composed of an interconnected network of blood vessels, which form using a number of different morphogenetic mechanisms. Angiogenesis describes the formation of new blood vessels from preexisting vessels. A number of molecular pathways have been shown to be essential during angiogenesis. However, cellular architecture of blood vessels as well as cellular mechanisms...

  20. Predictive Modelling of Cellular Load

    OpenAIRE

    Carolan, Emmett; McLoone, Seamus; Farrell, Ronan

    2015-01-01

    This work examines the temporal dynamics of cellular load in four Irish regions. Large scale underutilisation of network resources is identified both at the regional level and at the level of individual cells. Cellular load is modeled and prediction intervals are generated. These prediction intervals are used to put an upper bound on usage in a particular cell at a particular time. Opportunities for improvements in network utilization by incorporating these upper bounds on usage are identifie...

  1. Cellular automaton for chimera states

    OpenAIRE

    García-Morales, Vladimir

    2016-01-01

    A minimalistic model for chimera states is presented. The model is a cellular automaton (CA) which depends on only one adjustable parameter, the range of the nonlocal coupling, and is built from elementary cellular automata and the majority (voting) rule. This suggests the universality of chimera-like behavior from a new point of view: Already simple CA rules based on the majority rule exhibit this behavior. After a short transient, we find chimera states for arbitrary initial conditions, the...

  2. Nothing in the History of Spanish Anís Makes Sense, Except in the Light of Evolution

    Science.gov (United States)

    Delgado, Juan Antonio; Palma, Ricardo Luis

    2011-02-01

    We describe, discuss and illustrate a metaphoric parallel between the history of the most famous Spanish liqueur, " Anís del Mono" ( Anís 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 caricature of a simian Darwin with a positive connotation, perhaps the only one ever produced. We conclude that, like some species in the natural world, Anís of the Monkey has evolved, adapted, survived and become the fittest and most successful anís in the Spanish market and possibly the world. We hope this paper will contribute a new useful metaphor for the teaching of biological evolution.

  3. 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

  4. Mathematical models and multiscale simulations of cellular secretion processes

    OpenAIRE

    González-Vélez, Virginia

    2011-01-01

    Exocytosis is the cellular process whereby a product such as a hormone or a neurotransmitter is released as a response to stimulation. There are a lot of exocytotic cells in mammals, and each cell type has their specific subcellular mechanisms, needed to achieve the final substance release. Therefore, unveiling the role of subcellular mechanisms in secretion processes is highly relevant to understand disease evolution and possible therapies. The efficiency of the coupling between stimulus...

  5. Hierarchical Cellular Structures in High-Capacity Cellular Communication Systems

    CERN Document Server

    Jain, R K; Agrawal, N K

    2011-01-01

    In the prevailing cellular environment, it is important to provide the resources for the fluctuating traffic demand exactly in the place and at the time where and when they are needed. In this paper, we explored the ability of hierarchical cellular structures with inter layer reuse to increase the capacity of mobile communication network by applying total frequency hopping (T-FH) and adaptive frequency allocation (AFA) as a strategy to reuse the macro and micro cell resources without frequency planning in indoor pico cells [11]. The practical aspects for designing macro- micro cellular overlays in the existing big urban areas are also explained [4]. Femto cells are inducted in macro / micro / pico cells hierarchical structure to achieve the required QoS cost effectively.

  6. CELLULAR INTERACTIONS MEDIATED BY GLYCONECTIDS

    Directory of Open Access Journals (Sweden)

    O.Popescu

    1999-01-01

    Full Text Available Cellular interactions involve many types of cell surface molecules and operate via homophilic and/or heterophilic protein-protein and protein-carbohydrate binding. Our investigations in different model-systems (marine invertebrates and mammals have provided direct evidence that a novel class of primordial proteoglycans, named by us gliconectins, can mediate cell adhesion via a new alternative molecular mechanism of polyvalent carbohydrate-carbohydrate binding. Biochemical characterization of isolated and purified glyconectins revealed the presence of specific carbohydrate structures, acidic glycans, different from classical glycosaminoglycans. Such acidic glycans of high molecular weight containing fucose, glucuronic or galacturonic acids, and sulfate groups, originally found in sponges and sea urchin embryos, may represent a new class of carbohydrate carcino-embryonal antigens in mice and humans. Such interactions between biological macromolecules are usually investigated by kinetic binding studies, calorimetric methods, X-ray diffraction, nuclear magnetic resonance, and other spectroscopic analyses. However, these methods do not supply a direct estimation of the intermolecular binding forces that are fundamental for the function of the ligand-receptor association. Recently, we have introduced atomic force microscopy to quantify the binding strength between cell adhesion proteoglycans. Measurement of binding forces intrinsic to cell adhesion proteoglycans is necessary to assess their contribution to the maintenance of the anatomical integrity of multicellular organisms. As a model, we selected the glyconectin 1, a cell adhesion proteoglycan isolated from the marine sponge Microciona prolifera. This glyconectin mediates in vivo cell recognition and aggregation via homophilic, species-specific, polyvalent, and calcium ion-dependent carbohydrate-carbohydrate interactions. Under physiological conditions, an adhesive force of up to 400 piconewtons

  7. Continuum representations of cellular solids

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, M.K.

    1993-09-01

    Cellular materials consist of interconnected struts or plates which form cells. The struts or plates are constructed from a variety of metals, polymers, ceramics and wood products. Cellular materials are often used in impact limiters for shipping containers to protect the contents from accidental impact events. These materials exhibit a variety of complex behavior when subjected to crushing loads. This research focuses on the development of continuum representations of cellular solids that can be used in the finite element analysis of shipping container accidents. A significant portion of this work is the development of a new methodology to relate localized deformations to appropriate constitutive descriptions. This methodology provides the insight needed to select constitutive descriptions for cellular solids that capture the localized deformations that are observed experimentally. Constitutive relations are developed for two different cellular materials, aluminum honeycomb and polyurethane foam. These constitutive relations are based on plasticity and continuum damage theories. Plasticity is used to describe the permanent deformation exhibited by both aluminum honeycomb and polyurethane foam. Continuum damage is needed to capture the change in elastic parameters due to cracking of the polyurethane cell wall materials. The new constitutive description of polyurethane foam is implemented in both static and dynamic finite element codes, and analytical and numerical predictions are compared with available experimental data.

  8. Prognosis of Different Cellular Generations

    Directory of Open Access Journals (Sweden)

    Preetish Ranjan

    2013-04-01

    Full Text Available Technological advancement in mobile telephony from 1G to 3G, 4G and 5G has a very axiomatic fact that made an entire world a global village. The cellular system employs a different design approach and technology that most commercial radio and television system use. In the cellular system, the service area is divided into cells and a transmitter is designed to serve an individual cell. The system seeks to make efficient use of available channels by using low-power transmitters to allow frequency reuse at a smaller distance. Maximizing the number of times each channel can be reused in a given geographical area is the key to an efficient cellular system design. During the past three decades, the world has seen significant changes in telecommunications industry. There have been some remarkable aspects to the rapid growth in wireless communications, as seen by the large expansion in mobile systems. This paper focuses on “Past, Present & Future of Cellular Telephony” and some light has been thrown upon the technologies of the cellular systems, namely 1G, 2G, 2.5G, 3G and future generations like 4G and 5G systems as well.

  9. Evolution and Creation

    Directory of Open Access Journals (Sweden)

    Fiorenzo Facchini

    2013-05-01

    Full Text Available STATISTICA re-proposes a note of Fiorenzo Facchini — a distinguished anthropologist of the University of Bologna — published on the Osservatore Romano (17/01/2006 and cited by New York Times (18/01/2006. As the reader can easily observe, the strength of the Darwinian thought has provoked a deep reflection also inside the catholic tradition, witnessed here by a scientist that is at a same time a man of the church. After Darwin, such tradition has been forced to modify deeply its philosophical view about the real world.

  10. The Evolution of Biological Complexity in Digital Organisms

    Science.gov (United States)

    Ofria, Charles

    2013-03-01

    When Darwin first proposed his theory of evolution by natural selection, he realized that it had a problem explaining the origins of traits of ``extreme perfection and complication'' such as the vertebrate eye. Critics of Darwin's theory have latched onto this perceived flaw as a proof that Darwinian evolution is impossible. In anticipation of this issue, Darwin described the perfect data needed to understand this process, but lamented that such data are ``scarcely ever possible'' to obtain. In this talk, I will discuss research where we use populations of digital organisms (self-replicating and evolving computer programs) to elucidate the genetic and evolutionary processes by which new, highly-complex traits arise, drawing inspiration directly from Darwin's wistful thinking and hypotheses. During the process of evolution in these fully-transparent computational environments we can measure the incorporation of new information into the genome, a process akin to a natural Maxwell's Demon, and identify the original source of any such information. We show that, as Darwin predicted, much of the information used to encode a complex trait was already in the genome as part of simpler evolved traits, and that many routes must be possible for a new complex trait to have a high probability of successfully evolving. In even more extreme examples of the evolution of complexity, we are now using these same principles to examine the evolutionary dynamics the drive major transitions in evolution; that is transitions to higher-levels of organization, which are some of the most complex evolutionary events to occur in nature. Finally, I will explore some of the implications of this research to other aspects of evolutionary biology and as well as ways that these evolutionary principles can be applied toward solving computational and engineering problems.

  11. Evolution in health and disease: work in progress.

    Science.gov (United States)

    Stearns, S C; Ebert, D

    2001-12-01

    This article surveys progress in Darwinian medicine since 1991. Evolutionary thinking has been providing an increasing flow of fresh ideas into medical science, ideas that would not be suggested by other perspectives. Recent contributions have shed new light on the evolution of virulence, of antibiotic resistance, of oocytic atresia, of menopause, of the timing of the expression of genetic disease, of links between mate choice and disease resistance, and of genomic conflict between mother and fetus over resource provisioning. An important consequence of changes from the environment of evolutionary adaptedness concerns reproductive cancers; the incidence of reproductive cancers may be linked to changes in the frequency of menstruation in postindustrial societies. Other intriguing developments include some unanticipated and undesirable consequences of good hygiene, hope from an unexpected quarter for progress on nerve and muscle regeneration, evolutionary interpretations of mental disease, and insights from functional genomics into the nature of tradeoffs. The application of evolutionary thinking to problems in medical research and practice has thus yielded an abundant and growing harvest of insights. Some are well founded, others remain speculative. The field is moving from an initial phase dominated by speculation and hypothesis formation into a more rigorous phase of experimental testing of explicit alternatives. Currently the most promising areas, those in which experimental rigor can be applied efficiently, include experimental evolution and functional genomics. The pioneers can be proud of what they have set in motion. PMID:11783396

  12. 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.

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

    Science.gov (United States)

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

    2012-02-01

    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 paradigm. Recently, Cubo proposed a method to test whether morphological data in extant ratites are more compatible with a gradual or with a speciational model (close to the punctuated equilibrium model). As shown by our simulations, a new method to test the mode of evolution of characters (involving regression of standardized contrasts on their expected standard deviation) is easier to implement and more powerful than the previously proposed method, but the Mesquite module comet (aimed at investigating evolutionary models using comparative data) performs better still. Uncertainties in branch length estimates are probably the largest source of potential error. Cubo hypothesized that heterochronic mechanisms may underlie morphological changes in bone shape during the evolution of ratites. He predicted that the outcome of these changes may be consistent with a speciational model of character evolution because heterochronic changes can be instantaneous in terms of geological time. Analysis of a more extensive data set confirms his prediction despite branch length uncertainties: evolution in ratites has been mostly speciational for shape-related characters. However, it has been mostly gradual for size-related ones. PMID:22107024

  14. 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.

  15. Aging, cellular senescence, and cancer.

    Science.gov (United States)

    Campisi, Judith

    2013-01-01

    For most species, aging promotes a host of degenerative pathologies that are characterized by debilitating losses of tissue or cellular function. However, especially among vertebrates, aging also promotes hyperplastic pathologies, the most deadly of which is cancer. In contrast to the loss of function that characterizes degenerating cells and tissues, malignant (cancerous) cells must acquire new (albeit aberrant) functions that allow them to develop into a lethal tumor. This review discusses the idea that, despite seemingly opposite characteristics, the degenerative and hyperplastic pathologies of aging are at least partly linked by a common biological phenomenon: a cellular stress response known as cellular senescence. The senescence response is widely recognized as a potent tumor suppressive mechanism. However, recent evidence strengthens the idea that it also drives both degenerative and hyperplastic pathologies, most likely by promoting chronic inflammation. Thus, the senescence response may be the result of antagonistically pleiotropic gene action. PMID:23140366

  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 by...... 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...

  17. 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.

  18. Adaptive stochastic cellular automata: Applications

    Science.gov (United States)

    Qian, S.; Lee, Y. C.; Jones, R. D.; Barnes, C. W.; Flake, G. W.; O'Rourke, M. K.; Lee, K.; Chen, H. H.; Sun, G. Z.; Zhang, Y. Q.; Chen, D.; Giles, C. L.

    1990-09-01

    The stochastic learning cellular automata model has been applied to the problem of controlling unstable systems. Two example unstable systems studied are controlled by an adaptive stochastic cellular automata algorithm with an adaptive critic. The reinforcement learning algorithm and the architecture of the stochastic CA controller are presented. Learning to balance a single pole is discussed in detail. Balancing an inverted double pendulum highlights the power of the stochastic CA approach. The stochastic CA model is compared to conventional adaptive control and artificial neural network approaches.

  19. Cellular senescence in aging primates.

    Science.gov (United States)

    Herbig, Utz; Ferreira, Mark; Condel, Laura; Carey, Dee; Sedivy, John M

    2006-03-01

    The aging of organisms is characterized by a gradual functional decline of all organ systems. Mammalian somatic cells in culture display a limited proliferative life span, at the end of which they undergo an irreversible cell cycle arrest known as replicative senescence. Whether cellular senescence contributes to organismal aging has been controversial. We investigated telomere dysfunction, a recently discovered biomarker of cellular senescence, and found that the number of senescent fibroblasts increases exponentially in the skin of aging baboons, reaching >15% of all cells in very old individuals. In addition, the same cells contain activated ataxia-telangiectasia mutated kinase and heterochromatinized nuclei, confirming their senescent status. PMID:16456035

  20. Cellular automaton for chimera states

    Science.gov (United States)

    García-Morales, Vladimir

    2016-04-01

    A minimalistic model for chimera states is presented. The model is a cellular automaton (CA) which depends on only one adjustable parameter, the range of the nonlocal coupling, and is built from elementary cellular automata and the majority (voting) rule. This suggests the universality of chimera-like behavior from a new point of view: Already simple CA rules based on the majority rule exhibit this behavior. After a short transient, we find chimera states for arbitrary initial conditions, the system spontaneously splitting into stable domains separated by static boundaries, some synchronously oscillating and the others incoherent. When the coupling range is local, nontrivial coherent structures with different periodicities are formed.

  1. Prognosis of Different Cellular Generations

    OpenAIRE

    Preetish Ranjan; Prabhat Kumar

    2013-01-01

    Technological advancement in mobile telephony from 1G to 3G, 4G and 5G has a very axiomatic fact that made an entire world a global village. The cellular system employs a different design approach and technology that most commercial radio and television system use. In the cellular system, the service area is divided into cells and a transmitter is designed to serve an individual cell. The system seeks to make efficient use of available channels by using low-power transmitters to allow frequen...

  2. How cancer shapes evolution, and how evolution shapes cancer

    OpenAIRE

    Casás-Selves, Matias; DeGregori, James

    2011-01-01

    Evolutionary theories are critical for understanding cancer development at the level of species as well as at the level of cells and tissues, and for developing effective therapies. Animals have evolved potent tumor suppressive mechanisms to prevent cancer development. These mechanisms were initially necessary for the evolution of multi-cellular organisms, and became even more important as animals evolved large bodies and long lives. Indeed, the development and architecture of our tissues wer...

  3. 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

  4. Repaglinide at a cellular level

    DEFF Research Database (Denmark)

    Krogsgaard Thomsen, M; Bokvist, K; Høy, M;

    2002-01-01

    To investigate the hormonal and cellular selectivity of the prandial glucose regulators, we have undertaken a series of experiments, in which we characterised the effects of repaglinide and nateglinide on ATP-sensitive potassium ion (KATP) channel activity, membrane potential and exocytosis in ra...

  5. Cellular signalling properties in microcircuits

    DEFF Research Database (Denmark)

    Toledo-Rodriguez, Maria; El Manira, Abdeljabbar; Wallén, Peter; Svirskis, Gytis; Hounsgaard, Jørn

    2005-01-01

    Molecules and cells are the signalling elements in microcircuits. Recent studies have uncovered bewildering diversity in postsynaptic signalling properties in all areas of the vertebrate nervous system. Major effort is now being invested in establishing the specialized signalling properties at th...... cellular and molecular levels in microcircuits in specific brain regions. This review is part of the TINS Microcircuits Special Feature....

  6. Quantum Cloning by Cellular Automata

    OpenAIRE

    D'Ariano, G. M.; Macchiavello, C.; M. Rossi

    2012-01-01

    We introduce a quantum cellular automaton that achieves approximate phase-covariant cloning of qubits. The automaton is optimized for 1-to-2N economical cloning. The use of the automaton for cloning allows us to exploit different foliations for improving the performance with given resources.

  7. Analysis of cellular manufacturing systems

    NARCIS (Netherlands)

    Heragu, Sunderesh; Meng, Gang; Zijm, Henk; Ommeren, van Jan-Kees

    2001-01-01

    In this paper, we present an open queuing network modeling approach to estimate performance measures of a cellular manufacturing layout. It is assumed a layout and production data for a planning period of specified length are available. The production data takes into account, processing and handli

  8. Cellular scaling rules for the brain of Artiodactyla include a highly folded cortex with few neurons

    OpenAIRE

    Rodrigo eSiqueira Kazu; Jose eMaldonado; Bruno eMota; Paul eManger; Suzana eHerculano-Houzel

    2014-01-01

    Quantitative analysis of the cellular composition of rodent, primate, insectivore, and afrotherian brains has shown that non-neuronal scaling rules are similar across these mammalian orders that diverged about 95 million years ago, and therefore appear to be conserved in evolution, while neuronal scaling rules appear to be free to vary in a clade-specific manner. Here we analyze the cellular scaling rules that apply to the brain of artiodactyls, a group within the order Cetartiodactyla, belie...

  9. Stellar evolution

    CERN Document Server

    Meadows, A J

    2013-01-01

    Stellar Evolution, Second Edition covers the significant advances in the understanding of birth, life, and death of stars.This book is divided into nine chapters and begins with a description of the characteristics of stars according to their brightness, distance, size, mass, age, and chemical composition. The next chapters deal with the families, structure, and birth of stars. These topics are followed by discussions of the chemical composition and the evolution of main-sequence stars. A chapter focuses on the unique features of the sun as a star, including its evolution, magnetic fields, act

  10. 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.

  11. Non-local quantum evolution of entangled ensemble states in neural nets and its significance for brain function and a theory of consciousness

    CERN Document Server

    Bieberich, E

    1999-01-01

    Current quantum theories of consciousness suggest a configuration space of an entangled ensemble state as global work space for conscious experience. This study will describe a procedure for adjustment of the singlet evolution of a quantum computation to a classical signal input by action potentials. The computational output of an entangled state in a single neuron will be selected in a network environment by "survival of the fittest" coupling with other neurons. Darwinian evolution of this coupling will result in a binding of action potentials to a convoluted orbit of phase-locked oscillations with harmonic, m-adic, or fractal periodicity. Progressive integration of signal inputs will evolve a present memory space independent from the history of construction. Implications for mental processes, e.g., associative memory, creativity, and consciousness will be discussed. A model for the generation of quantum coherence in a single neuron will be suggested.

  12. Schumpeter's Evolution

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    This draft of a book on Schumpeter is distributed for commenting. It is a stylised intellectual biography that focus on the emergence and extension of the Schumpeterian vision and analysis of economic and social evolution. The draft provides novel interpretations of Schumpeter's six major books. He...... reworking of his basic theory of economic evolution in Development from 1934, and this reworking was continued in Cycles from 1939. Here Schumpeter also tried to handle the statistical and historical evidence on the waveform evolution of the capitalist economy. Capitalism from 1942 modified the model of...... economic evolution and added evolutionary contributions to other social sciences. History, which was published by his widow, was based on his evolutionary theory of the history of economic analysis. This sequential analysis of Schumpeter's six books demonstrates the progress he within his research...

  13. Cellular solidification of transparent monotectics

    Science.gov (United States)

    Kaulker, W. F.

    1986-01-01

    Understanding how liquid phase particles are engulfed or pushed during freezing of a monotectic is addressed. The additional complication is that the solid-liquid interface is nonplanar due to constitutional undercooling. Some evidence of particle pushing where the particles are the liquid phase of the montectic was already observed. Cellular freezing of the succinonitrile-glycerol system also occurred. Only a few compositions were tested at that time. The starting materials were not especially pure so that cellular interface observed was likely due to the presence of unkown impurities, the major portion of which was water. Topics addressed include: the effort of modeling the particle pushing process using the computer, establishing an apparatus for the determination of phase diagrams, and the measurement of the temperature gradients with a specimen which will solidify on the temperature gradient microscope stage.

  14. Cellular ceramics in combustion environments

    Energy Technology Data Exchange (ETDEWEB)

    Fuessel, Alexander; Boettge, Daniela; Adler, Joerg; Marschallek, Felix; Michaelis, Alexander [Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Dresden (Germany)

    2011-11-15

    Cellular materials have become increasingly interesting for applications in combustion environments. Improvements like high power efficiency and low emissions are the main targets of technological development in combustion processes. However, despite scientific and technical success in developing new or improved burner concepts over recent years, a lot of problems remain to be solved in the field of materials science: due to the high power density of the burners the materials are subjected to high loads in terms of thermal shock, temperature and corrosion, especially in so-called porous burner technology. This article shows some examples of research and development strategies and results in developing improved cellular ceramics. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Designing Underwater Cellular Networks Parameters

    Directory of Open Access Journals (Sweden)

    Pejman Khadivi

    2008-09-01

    Full Text Available Oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, assisted navigation and tactical surveillance are some of the applications of underwater networks. Underwater networks should send the gathered information to other users or an offshore station via a base station in the sea. Since the available bandwidth in underwater is severely limited, frequency reuse and cellular networks concepts are very important. In this paper, after driving the ratio of signal to interference for underwater acoustic channels, the constraints for the cell radius are determined. One of the important results of this work is that, for special parameters like bandwidth, it may be impossible to provide the required signal to interference ratio and bandwidth for the network users. Furthermore, in this paper, number of supportable users, per-user bandwidth, and the user capacity for a cellular underwater network are determined.

  16. Stochastic Nature in Cellular Processes

    Institute of Scientific and Technical Information of China (English)

    刘波; 刘圣君; 王祺; 晏世伟; 耿轶钊; SAKATA Fumihiko; GAO Xing-Fa

    2011-01-01

    The importance of stochasticity in cellular processes is increasingly recognized in both theoretical and experimental studies. General features of stochasticity in gene regulation and expression are briefly reviewed in this article, which include the main experimental phenomena, classification, quantization and regulation of noises. The correlation and transmission of noise in cascade networks are analyzed further and the stochastic simulation methods that can capture effects of intrinsic and extrinsic noise are described.

  17. Xtoys cellular automata on xwindows

    CERN Document Server

    Creutz, M

    1995-01-01

    Xtoys is a collection of xwindow programs for demonstrating simulations of various statistical models. Included are xising, for the two dimensional Ising model, xpotts, for the q-state Potts model, xautomalab, for a fairly general class of totalistic cellular automata, xsand, for the Bak-Tang-Wiesenfield model of self organized criticality, and xfires, a simple forest fire simulation. The programs should compile on any machine supporting xwindows.

  18. Cellular reactions to patterned biointerfaces

    OpenAIRE

    Schulte, Vera Antonie

    2012-01-01

    The subject of this thesis is to study cellular reactions to topographically, mechanically and biochemically tunable polymeric biomaterials. Different aspects of in vitro cell-biomaterial interactions were systematically studied with the murine fibroblast cell line NIH L929 and primary human dermal fibroblasts (HDFs). Besides a general cytocompatibility assessment of the applied materials and the quantification of cell adhesion per se, cell morphological changes (e.g. cell spreading) and intr...

  19. Signal processing in cellular clocks

    OpenAIRE

    Forger, Daniel B.

    2011-01-01

    Many biochemical events within a cell need to be timed properly to occur at specific times of day, after other events have happened within the cell or in response to environmental signals. The cellular biochemical feedback loops that time these events have already received much recent attention in the experimental and modeling communities. Here, we show how ideas from signal processing can be applied to understand the function of these clocks. Consider two signals from the network s(t) and r(...

  20. Analysis of cellular manufacturing systems

    OpenAIRE

    Heragu, Sunderesh; Meng, Gang; Zijm, Henk; Ommeren, van, J.C.

    2001-01-01

    In this paper, we present an open queuing network modeling approach to estimate performance measures of a cellular manufacturing layout. It is assumed a layout and production data for a planning period of specified length are available. The production data takes into account, processing and handling set-up times as well as transfer and process batch size information of multiple products that flow through the system. It is assumed that two sets of discrete material handling devices are used fo...

  1. Cellular Dynamics of RNA Modification

    OpenAIRE

    Yi, Chengqi; Pan, Tao

    2011-01-01

    Decades of research have identified over 100 types of ribonucleosides that are post-transcriptionally modified. Many modified nucleosides are conserved in bacteria, archeae and eukaryotes, while some modified nucleosides are unique to each branch of life. However, the cellular and functional dynamics of RNA modifications remains largely unexplored, mostly due to the lack of functional hypotheses and experimental methods for quantification and large scale analysis. Just as many well characteri...

  2. Cellular Dynamics of RNA Modification

    Science.gov (United States)

    Yi, Chengqi; Pan, Tao

    2011-01-01

    Conspectus Decades of research have identified over 100 types of ribonucleosides that are post-transcriptionally modified. Many modified nucleosides are conserved in bacteria, archeae and eukaryotes, while some modified nucleosides are unique to each branch of life. However, the cellular and functional dynamics of RNA modifications remains largely unexplored, mostly due to the lack of functional hypotheses and experimental methods for quantification and large scale analysis. Just as many well characterized protein and DNA modifications, many RNA modifications are not essential for life. Instead, increasingly more evidence indicates that RNA modifications can play regulatory roles in cells, especially in response to stress conditions. In this Account, we review some known examples of RNA modifications that are dynamically controlled in cells and introduce some contemporary technologies and methods that enhance the studies of cellular dynamics of RNA modifications. Examples of RNA modifications discussed in this Account include (Figure 1): (1) 4-thio uridine (s4U) which can act as a cellular sensor of near UV-light; (2) queuosine (Q) which is a potential biomarker for malignancy; (3) N6-methyl adenine (m6A) which is the prevalent modification in eukaryotic mRNAs; and (4) pseudouridine (ψ) which are inducible by nutrient deprivation. Two recent technical advances that stimulated the studies of cellular dynamics of modified ribonucleosides are also described. First, a genome-wide method combines primer extension and microarray to study N1-methyl adenine (m1A) hypomodification in human tRNA. Second, a quantitative mass spectrometric method investigates dynamic changes of a wide range of tRNA modifications under stress conditions in yeast. In addition, we discuss potential mechanisms that control dynamic regulation of RNA modifications, and hypotheses for discovering potential RNA de-modification enzymes. We conclude the Account by highlighting the need to develop new

  3. CELLULAR FETAL MICROCHIMERISM IN PREECLAMPSIA

    OpenAIRE

    Gammill, Hilary S; Aydelotte, Tessa M.; Guthrie, Katherine A.; Nkwopara, Evangelyn C.; Nelson, J. Lee

    2013-01-01

    Previous studies have shown elevated concentrations of free fetal deoxyribonucleic acid and erythroblasts in maternal circulation in preeclampsia compared with normal pregnancy. Pluripotent and immunocompetent fetal cells also transfer to the maternal circulation during pregnancy, but whether concentrations of fetal mononuclear cells also differed in preeclampsia was unknown. We sought to quantify cellular fetal microchimerism in maternal circulation in women with preeclampsia and healthy con...

  4. Progress of cellular dedifferentiation research

    Institute of Scientific and Technical Information of China (English)

    LIU Hu-xian; HU Da-hai; JIA Chi-yu; FU Xiao-bing

    2006-01-01

    Differentiation, the stepwise specialization of cells, and transdifferentiation, the apparent switching of one cell type into another, capture much of the stem cell spotlight. But dedifferentiation, the developmental reversal of a cell before it reinvents itself, is an important process too. In multicellular organisms, cellular dedifferentiation is the major process underlying totipotency, regeneration and formation of new stem cell lineages. In humans,dedifferentiation is often associated with carcinogenesis.The study of cellular dedifferentiation in animals,particularly early events related to cell fate-switch and determination, is limited by the lack of a suitable,convenient experimental system. The classic example of dedifferentiation is limb and tail regeneration in urodele amphibians, such as salamanders. Recently, several investigators have shown that certain mammalian cell types can be induced to dedifferentiate to progenitor cells when stimulated with the appropriate signals or materials. These discoveries open the possibility that researchers might enhance the endogenous regenerative capacity of mammals by inducing cellular dedifferentiation in vivo.

  5. Dynamic properties of cellular neural networks

    Directory of Open Access Journals (Sweden)

    Angela Slavova

    1993-01-01

    Full Text Available Dynamic behavior of a new class of information-processing systems called Cellular Neural Networks is investigated. In this paper we introduce a small parameter in the state equation of a cellular neural network and we seek for periodic phenomena. New approach is used for proving stability of a cellular neural network by constructing Lyapunov's majorizing equations. This algorithm is helpful for finding a map from initial continuous state space of a cellular neural network into discrete output. A comparison between cellular neural networks and cellular automata is made.

  6. 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

  7. Kinetic Monte Carlo and Cellular Particle Dynamics Simulations of Multicellular Systems

    CERN Document Server

    Flenner, Elijah; Barz, Bogdan; Neagu, Adrian; Forgacs, Gabor; Kosztin, Ioan

    2011-01-01

    Computer modeling of multicellular systems has been a valuable tool for interpreting and guiding in vitro experiments relevant to embryonic morphogenesis, tumor growth, angiogenesis and, lately, structure formation following the printing of cell aggregates as bioink particles. Computer simulations based on Metropolis Monte Carlo (MMC) algorithms were successful in explaining and predicting the resulting stationary structures (corresponding to the lowest adhesion energy state). Here we introduce two alternatives to the MMC approach for modeling cellular motion and self-assembly: (1) a kinetic Monte Carlo (KMC), and (2) a cellular particle dynamics (CPD) method. Unlike MMC, both KMC and CPD methods are capable of simulating the dynamics of the cellular system in real time. In the KMC approach a transition rate is associated with possible rearrangements of the cellular system, and the corresponding time evolution is expressed in terms of these rates. In the CPD approach cells are modeled as interacting cellular ...

  8. 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

  9. Return of the Quantum Cellular Automata: Episode VI

    Science.gov (United States)

    Carr, Lincoln D.; Hillberry, Logan E.; Rall, Patrick; Halpern, Nicole Yunger; Bao, Ning; Montangero, Simone

    2016-05-01

    There are now over 150 quantum simulators or analog quantum computers worldwide. Although exploring quantum phase transitions, many-body localization, and the generalized Gibbs ensemble are exciting and worthwhile endeavors, there are totally untapped directions we have not yet pursued. One of these is quantum cellular automata. In the past a principal goal of quantum cellular automata was to reproduce continuum single particle quantum physics such as the Schrodinger or Dirac equation from simple rule sets. Now that we begin to really understand entanglement and many-body quantum physics at a deeper level, quantum cellular automata present new possibilities. We explore several time evolution schemes on simple spin chains leading to high degrees of quantum complexity and nontrivial quantum dynamics. We explain how the 256 known classical elementary cellular automata reduce to just a few exciting quantum cases. Our analysis tools include mutual information based complex networks as well as more familiar quantifiers like sound speed and diffusion rate. Funded by NSF and AFOSR.

  10. Detecting lineage-specific adaptive evolution of brain-expressed genes in human using rhesus macaque as outgroup

    DEFF Research Database (Denmark)

    Yu, Xiao-Jing; Zheng, Hong-Kun; Wang, Jun;

    2006-01-01

    Comparative genetic analysis between human and chimpanzee may detect genetic divergences responsible for human-specific characteristics. Previous studies have identified a series of genes that potentially underwent Darwinian positive selection during human evolution. However, without a closely...... related species as outgroup, it is difficult to identify human-lineage-specific changes, which is critical in delineating the biological uniqueness of humans. In this study, we conducted phylogeny-based analyses of 2633 human brain-expressed genes using rhesus macaque as the outgroup. We identified 47...... candidate genes showing strong evidence of positive selection in the human lineage. Genes with maximal expression in the brain showed a higher evolutionary rate in human than in chimpanzee. We observed that many immune-defense-related genes were under strong positive selection, and this trend was more...

  11. Urban DNA for cities evolutions. Cities as physical expression of dynamic equilibriums between competitive and cooperative forces

    CERN Document Server

    D'Acci, Luca

    2014-01-01

    Cities are physical manifestations of our competitive and cooperative behaviours. The tension between these two forces generates dynamic equilibriums whose material expressions are cities and their evolutions. In a Darwinian cooperative view, as Darwinism does not involve only competition, the public benefit obtained by cooperation, return in terms of private benefit too. An urban genetic code is proposed, according to which cities emerge connecting nature and urbanity, and as sum of multiuse, independent micro-areas, each one with its centrality, job locations, parks and daily shops-services and amenities. This mechanism, called Isobenefit Urbanism, is not static and pre-designed, but allows infinitely dynamic changes and expansions. Rather than describing The ideal city, which doesn't exist outside our own minds, Isobenefit Urbanism describes what a city should avoid to be in order to not become an unideal city. Its six principles are the urban DNA which does not give predetermined forms but indications to ...

  12. lincRNAs: Genomics, Evolution, and Mechanisms

    OpenAIRE

    Ulitsky, Igor; Bartel, David P.

    2013-01-01

    Long intervening noncoding RNAs (lincRNAs) are transcribed from thousands of loci in mammalian genomes and might play widespread roles in gene regulation and other cellular processes. This Review outlines the emerging understanding of lincRNAs in vertebrate animals, with emphases on how they are being identified and current conclusions and questions regarding their genomics, evolution and mechanisms of action.

  13. Stochastic resonance and the evolution of Daphnia foraging strategy

    International Nuclear Information System (INIS)

    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)

  14. Cellular host responses to gliomas.

    Directory of Open Access Journals (Sweden)

    Joseph Najbauer

    Full Text Available BACKGROUND: Glioblastoma multiforme (GBM is the most aggressive type of malignant primary brain tumors in adults. Molecular and genetic analysis has advanced our understanding of glioma biology, however mapping the cellular composition of the tumor microenvironment is crucial for understanding the pathology of this dreaded brain cancer. In this study we identified major cell populations attracted by glioma using orthotopic rodent models of human glioma xenografts. Marker-specific, anatomical and morphological analyses revealed a robust influx of host cells into the main tumor bed and tumor satellites. METHODOLOGY/PRINCIPAL FINDINGS: Human glioma cell lines and glioma spheroid orthotopic implants were used in rodents. In both models, the xenografts recruited large numbers of host nestin-expressing cells, which formed a 'network' with glioma. The host nestin-expressing cells appeared to originate in the subventricular zone ipsilateral to the tumor, and were clearly distinguishable from pericytes that expressed smooth muscle actin. These distinct cell populations established close physical contact in a 'pair-wise' manner and migrated together to the deeper layers of tumor satellites and gave rise to tumor vasculature. The GBM biopsy xenografts displayed two different phenotypes: (a low-generation tumors (first in vivo passage in rats were highly invasive and non-angiogenic, and host nestin-positive cells that infiltrated into these tumors displayed astrocytic or elongated bipolar morphology; (b high-generation xenografts (fifth passage had pronounced cellularity, were angiogenic with 'glomerulus-like' microvascular proliferations that contained host nestin-positive cells. Stromal cell-derived factor-1 and its receptor CXCR4 were highly expressed in and around glioma xenografts, suggesting their role in glioma progression and invasion. CONCLUSIONS/SIGNIFICANCE: Our data demonstrate a robust migration of nestin-expressing host cells to glioma, which

  15. Game of Life Cellular Automata

    CERN Document Server

    Adamatzky, Andrew

    2010-01-01

    In the late 1960s, British mathematician John Conway invented a virtual mathematical machine that operates on a two-dimensional array of square cell. Each cell takes two states, live and dead. The cells' states are updated simultaneously and in discrete time. A dead cell comes to life if it has exactly three live neighbours. A live cell remains alive if two or three of its neighbours are alive, otherwise the cell dies. Conway's Game of Life became the most programmed solitary game and the most known cellular automaton. The book brings together results of forty years of study into computational

  16. Cellular automata a parallel model

    CERN Document Server

    Mazoyer, J

    1999-01-01

    Cellular automata can be viewed both as computational models and modelling systems of real processes. This volume emphasises the first aspect. In articles written by leading researchers, sophisticated massive parallel algorithms (firing squad, life, Fischer's primes recognition) are treated. Their computational power and the specific complexity classes they determine are surveyed, while some recent results in relation to chaos from a new dynamic systems point of view are also presented. Audience: This book will be of interest to specialists of theoretical computer science and the parallelism challenge.

  17. Estimation in Cellular Radio Systems

    OpenAIRE

    Blom, Jonas; Gunnarsson, Fredrik; Gustafsson, Fredrik

    1999-01-01

    The problem to track time-varying parameters in cellular radio systems is studied, and the focus is on estimation based only on the signals that are readily available. Previous work have demonstrated very good performance, but were relying on analog measurement that are not available. Most of the information is lost due to quantization and sampling at a rate that might be as low as 2 Hz (GSM case). For that matter a maximum likelihood estimator have been designed and exemplified in the case o...

  18. 'Biomoleculas': cellular metabolism didactic software

    International Nuclear Information System (INIS)

    'Biomoleculas' is a software that deals with topics such as the digestion, cellular metabolism and excretion of nutrients. It is a pleasant, simple and didactic guide, made by and for students. In this program, each biomolecule (carbohydrates, lipids and proteins) is accompanied until its degradation and assimilation by crossing and interrelating the different metabolic channels to finally show the destination of the different metabolites formed and the way in which these are excreted. It is used at present as a teaching-learning process tool by the chair of Physiology and Biophysics at the Facultad de Ingenieria - Universidad Nacional de Entre Rios

  19. Protein accounting in the cellular economy

    Science.gov (United States)

    Vázquez-Laslop, Nora; Mankin, Alexander S.

    2014-01-01

    Knowing the copy number of cellular proteins is critical for understanding cell physiology. By being able to measure the absolute synthesis rates of the majority of cellular proteins, Li et al. (2014) gain insights into key aspects of translation regulation and fundamental principles of cellular strategies to adjust protein synthesis according to the needs. PMID:24766801

  20. Cellular Functions of Transient Receptor Potential channels

    OpenAIRE

    Dadon, Daniela; Minke, Baruch

    2010-01-01

    Transient Receptor Potential channels are polymodal cellular sensors involved in a wide variety of cellular processes, mainly by increasing cellular Ca2+. In this review we focus on the roles of these channels in: i) cell death ii) proliferation and differentiation and iii) synaptic vesicle release.

  1. 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.

  2. Cellular automata modelling of phase-change memories

    Institute of Scientific and Technical Information of China (English)

    Wanhua Yu; David Wright

    2008-01-01

    A novel approach to modelling phase-transition processes in phase change materials used for optical and electrical data storage applications is presented. The model is based on a cellular automaton (CA) approach to predict crystallization behaviour that is linked to thermal and electrical simulations to enable the study of the data writing and erasing processes. The CA approach is shown to be able to predict the evolution of the microstructure during the rapid heating and cooling cycles pertinent to data storage technology, and maps crystallization behaviour on the nanoscale. A simple example based on possible future nonvolatile phase-change random access solid-state memory is presented.

  3. The loss of the hemoglobin H2S-binding function in annelids from sulfide-free habitats reveals molecular adaptation driven by Darwinian positive selection.

    Science.gov (United States)

    Bailly, Xavier; Leroy, Riwanon; Carney, Susan; Collin, Olivier; Zal, Franck; Toulmond, Andre; Jollivet, Didier

    2003-05-13

    The hemoglobin of the deep-sea hydrothermal vent vestimentiferan Riftia pachyptila (annelid) is able to bind toxic hydrogen sulfide (H(2)S) to free cysteine residues and to transport it to fuel endosymbiotic sulfide-oxidising bacteria. The cysteine residues are conserved key amino acids in annelid globins living in sulfide-rich environments, but are absent in annelid globins from sulfide-free environments. Synonymous and nonsynonymous substitution analysis from two different sets of orthologous annelid globin genes from sulfide rich and sulfide free environments have been performed to understand how the sulfide-binding function of hemoglobin appeared and has been maintained during the course of evolution. This study reveals that the sites occupied by free-cysteine residues in annelids living in sulfide-rich environments and occupied by other amino acids in annelids from sulfide-free environments, have undergone positive selection in annelids from sulfide-free environments. We assumed that the high reactivity of cysteine residues became a disadvantage when H(2)S disappeared because free cysteines without their natural ligand had the capacity to interact with other blood components, disturb homeostasis, reduce fitness and thus could have been counterselected. To our knowledge, we pointed out for the first time a case of function loss driven by molecular adaptation rather than genetic drift. If constraint relaxation (H(2)S disappearance) led to the loss of the sulfide-binding function in modern annelids from sulfide-free environments, our work suggests that adaptation to sulfide-rich environments is a plesiomorphic feature, and thus that the annelid ancestor could have emerged in a sulfide-rich environment. PMID:12721359

  4. [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

  5. Quantum state transfer through noisy quantum cellular automata

    International Nuclear Information System (INIS)

    We model the transport of an unknown quantum state on one dimensional qubit lattices by means of a quantum cellular automata (QCA) evolution. We do this by first introducing a class of discrete noisy dynamics, in the first excitation sector, in which a wide group of classical stochastic dynamics is embedded within the more general formalism of quantum operations. We then extend the Hilbert space of the system to accommodate a global vacuum state, thus allowing for the transport of initial on-site coherences besides excitations, and determine the dynamical constraints that define the class of noisy QCA in this subspace. We then study the transport performance through numerical simulations, showing that for some instances of the dynamics perfect quantum state transfer is attainable. Our approach provides one with a natural description of both unitary and open quantum evolutions, where the homogeneity and locality of interactions allow one to take into account several forms of quantum noise in a plausible scenario. (paper)

  6. Cellular computation using classifier systems

    OpenAIRE

    Kelly, Ciaran; Decraene, James, Lobo, Victor; Mitchell, George G.; McMullin, Barry; O'Brien, Darragh

    2006-01-01

    The EU FP6 Integrated Project PACE ('Programmable Artificial Cell Evolution') is investigating the creation, de novo, of chemical 'protocells'. These will be minimal 'wetware' chemical systems integrating molecular information carriers, primitive energy conversion (metabolism) and containment (membrane). Ultimately they should be capable of autonomous reproduction, and be 'programmable' to realise specific desired function. A key objective of PACE is to explore the application of such pro...

  7. Nanomechanics of Hierarchical Cellular Solids

    OpenAIRE

    Chen, Qiang

    2012-01-01

    Materials Science and Engineering, a young and vibrant discipline with its inception in the 1950s, has expanded into three directions: metals, polymers, and ceramics (and their mixtures, composites). Beyond the traditional scope, biological materials have drawn much attention since 1990s due to their optimal structures, which rise from hundreds of million years of evolution. Generally, biological materials are complex composites and possess varieties of hierarchical structures, multifunctiona...

  8. Universal map for cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    García-Morales, V., E-mail: vmorales@ph.tum.de [Institute for Advanced Study – Technische Universität München, Lichtenbergstr. 2a, D-85748 Garching (Germany)

    2012-08-20

    A universal map is derived for all deterministic 1D cellular automata (CAs) containing no freely adjustable parameters and valid for any alphabet size and any neighborhood range (including non-symmetrical neighborhoods). The map can be extended to an arbitrary number of dimensions and topologies and to arbitrary order in time. Specific CA maps for the famous Conway's Game of Life and Wolfram's 256 elementary CAs are given. An induction method for CAs, based in the universal map, allows mathematical expressions for the orbits of a wide variety of elementary CAs to be systematically derived. -- Highlights: ► A universal map is derived for all deterministic 1D cellular automata (CA). ► The map is generalized to 2D for Von Neumann, Moore and hexagonal neighborhoods. ► A map for all Wolfram's 256 elementary CAs is derived. ► A map for Conway's “Game of Life” is obtained.

  9. Representing Evolution

    DEFF Research Database (Denmark)

    Hedin, Gry

    2012-01-01

    article discusses Willumsen's etching in the context of evolutionary theory, arguing that Willumsen is a rare example of an artist who not only let the theory of evolution fuel his artistic imagination, but also concerned himself with a core issue of the theory, namely to what extent it could be applied...

  10. Cepheid evolution

    International Nuclear Information System (INIS)

    A review of the phases of stellar evolution relevant to Cepheid variables of both Types I and II is presented. Type I Cepheids arise as a result of normal post-main sequence evolutionary behavior of many stars in the intermediate to massive range of stellar masses. In contrast, Type II Cepheids generally originate from low-mass stars of low metalicity which are undergoing post core helium-burning evolution. Despite great progress in the past two decades, uncertainties still remain in such areas as how to best model convective overshoot, semiconvection, stellar atmospheres, rotation, and binary evolution as well as uncertainties in important physical parameters such as the nuclear reaction rates, opacity, and mass loss rates. The potential effect of these uncertainties on stellar evolution models is discussed. Finally, comparisons between theoretical predictions and observations of Cepheid variables are presented for a number of cases. The results of these comparisons show both areas of agreement and disagreement with the latter result providing incentive for further research

  11. Cellular structure of space near time singularity in the Einstein equations

    International Nuclear Information System (INIS)

    Taking one of the general cosmological solutions as an example it is shown, that under the metric evolution to singularity in stochastic oscillation regime areas with small-scale cellular structure of 3-geometry are formed near it. Statistics of indices and time dependence of lengths in such areas are investigated

  12. A study of a main-road cellular automata traffic flow model

    Institute of Scientific and Technical Information of China (English)

    黄乒花; 孔令江; 刘慕仁

    2002-01-01

    A main-road cellular automata traffic flow model on two dimensions is presented based on the Biham-Middleton-Levine traffic model. Its evolution equations are given and the self-organization and organization cooperation phenomenain this model are also studied by using computer simulation.

  13. 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 ...

  14. Phenotypic Evolution With and Beyond Genome Evolution.

    Science.gov (United States)

    Félix, M-A

    2016-01-01

    DNA does not make phenotypes on its own. In this volume entitled "Genes and Phenotypic Evolution," the present review draws the attention on the process of phenotype construction-including development of multicellular organisms-and the multiple interactions and feedbacks between DNA, organism, and environment at various levels and timescales in the evolutionary process. First, during the construction of an individual's phenotype, DNA is recruited as a template for building blocks within the cellular context and may in addition be involved in dynamical feedback loops that depend on the environmental and organismal context. Second, in the production of phenotypic variation among individuals, stochastic, environmental, genetic, and parental sources of variation act jointly. While in controlled laboratory settings, various genetic and environmental factors can be tested one at a time or in various combinations, they cannot be separated in natural populations because the environment is not controlled and the genotype can rarely be replicated. Third, along generations, genotype and environment each have specific properties concerning the origin of their variation, the hereditary transmission of this variation, and the evolutionary feedbacks. Natural selection acts as a feedback from phenotype and environment to genotype. This review integrates recent results and concrete examples that illustrate these three points. Although some themes are shared with recent calls and claims to a new conceptual framework in evolutionary biology, the viewpoint presented here only means to add flesh to the standard evolutionary synthesis. PMID:27282029

  15. A paradigm for viewing biologic systems as scale-free networks based on energy efficiency: implications for present therapies and the future of evolution.

    Science.gov (United States)

    Yun, Anthony J; Lee, Patrick Y; Doux, John D

    2006-01-01

    A network constitutes an abstract description of the relationships among entities, respectively termed links and nodes. If a power law describes the probability distribution of the number of links per node, the network is said to be scale-free. Scale-free networks feature link clustering around certain hubs based on preferential attachments that emerge due either to merit or legacy. Biologic systems ranging from sub-atomic to ecosystems represent scale-free networks in which energy efficiency forms the basis of preferential attachments. This paradigm engenders a novel scale-free network theory of evolution based on energy efficiency. As environmental flux induces fitness dislocations and compels a new meritocracy, new merit-based hubs emerge, previously merit-based hubs become legacy hubs, and network recalibration occurs to achieve system optimization. To date, Darwinian evolution, characterized by innovation sampling, variation, and selection through filtered termination, has enabled biologic progress through optimization of energy efficiency. However, as humans remodel their environment, increasing the level of unanticipated fitness dislocations and inducing evolutionary stress, the tendency of networks to exhibit inertia and retain legacy hubs engender maladaptations. Many modern diseases may fundamentally derive from these evolutionary displacements. Death itself may constitute a programmed adaptation, terminating individuals who represent legacy hubs and recalibrating the network. As memes replace genes as the basis of innovation, death itself has become a legacy hub. Post-Darwinian evolution may favor indefinite persistence to optimize energy efficiency. We describe strategies to reprogram or decommission legacy hubs that participate in human disease and death. PMID:16580786

  16. Thermomechanical characterisation of cellular rubber

    Science.gov (United States)

    Seibert, H.; Scheffer, T.; Diebels, S.

    2016-01-01

    This contribution discusses an experimental possibility to characterise a cellular rubber in terms of the influence of multiaxiality, rate dependency under environmental temperature and its behaviour under hydrostatic pressure. In this context, a mixed open and closed cell rubber based on an ethylene propylene diene monomer is investigated exemplarily. The present article intends to give a general idea of the characterisation method and the considerable effects of this special type of material. The main focus lies on the experimental procedure and the used testing devices in combination with the analysis methods such as true three-dimensional digital image correlation. The structural compressibility is taken into account by an approach for a material model using the Theory of Porous Media with additional temperature dependence.

  17. Discrete geodesics and cellular automata

    CERN Document Server

    Arrighi, Pablo

    2015-01-01

    This paper proposes a dynamical notion of discrete geodesics, understood as straightest trajectories in discretized curved spacetime. The notion is generic, as it is formulated in terms of a general deviation function, but readily specializes to metric spaces such as discretized pseudo-riemannian manifolds. It is effective: an algorithm for computing these geodesics naturally follows, which allows numerical validation---as shown by computing the perihelion shift of a Mercury-like planet. It is consistent, in the continuum limit, with the standard notion of timelike geodesics in a pseudo-riemannian manifold. Whether the algorithm fits within the framework of cellular automata is discussed at length. KEYWORDS: Discrete connection, parallel transport, general relativity, Regge calculus.

  18. Cellular compartmentalization of secondary metabolism

    Directory of Open Access Journals (Sweden)

    H. Corby eKistler

    2015-02-01

    Full Text Available Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g. amino acids, acetyl CoA, NADPH, enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

  19. Cellular tolerance to pulsed heating

    Science.gov (United States)

    Simanovski, Dimitrii; Sarkar, M.; Irani, A.; O'Connell-Rodwell, C.; Contag, C.; Schwettman, H. Alan; Palanker, D.

    2005-04-01

    Many laser therapies involve significant heating of tissue with pulses varying from picoseconds to minutes in duration. In some of the applications heating is a primary goal, while in others it is an undesirable side effect. In both cases, if a hyperthermia is involved, the knowledge about the threshold temperature leading to irreversible cellular damage is critically important. We study the dependence of the threshold temperature on duration of the heat exposure in the range of 0.3 ms to 5 seconds. Thin layer of cells cultured in a Petri dish was exposed to a pulsed CO2 laser radiation. Laser beam was focused onto sample providing Gaussian intensity distribution in the focal plane with a beam diameter (2w) 2-10 mm. Surface temperature in the central part of the focal spot (1mm in diameter) was measured by thermal infrared (IR) emission from the sample, recorded with a fast IR detector. For pulses shorter than 1 s the temperature profile across the focal spot was found to closely correspond to the radial distribution of the laser beam intensity, thus allowing for accurate determination of temperature at any given distance from the center of the spot. Immediate cellular damage was assessed using vital staining with the live/dead fluorescent assay. Threshold temperatures were found to vary from 65 °C at 5 s of heating to 160 °C at pulses of 0.3 ms in duration. The shorter end of this range was limited by vaporization, which occurs during the laser pulse and results in mechanical damage to cells. Dependence of the maximal temperature on pulse duration could be approximated by Arrhenius law with activation energy being about 1 eV.

  20. Membrane-Based Functions in the Origin of Cellular Life

    Science.gov (United States)

    Chipot, Christophe; New, Michael H.; Schweighofer, Karl; Pohorille, Andrew; Wilson, Michael A.

    1999-01-01

    Our objective is to help explain how the earliest ancestors of contemporary cells (protocells) performed their essential functions employing only the molecules available in the protobiological milieu. Our hypothesis is that vesicles, built of amphiphilic, membrane-forming materials, emerged early in protobiological evolution and served as precursors to protocells. We further assume that the cellular functions associated with contemporary membranes, such as capturing and, transducing of energy, signaling, or sequestering organic molecules and ions, evolved in these membrane environments. An alternative hypothesis is that these functions evolved in different environments and were incorporated into membrane-bound structures at some later stage of evolution. We focus on the application of the fundamental principles of physics and chemistry to determine how they apply to the formation of a primitive, functional cell. Rather than attempting to develop specific models for cellular functions and to identify the origin of the molecules which perform these functions, our goal is to define the structural and energetic conditions that any successful model must fulfill, therefore providing physico-chemical boundaries for these models. We do this by carrying out large-scale, molecular level computer simulations on systems of interest.

  1. Mitochondrial Evolution

    OpenAIRE

    Gray, Michael W

    2012-01-01

    Viewed through the lens of the genome it contains, the mitochondrion is of unquestioned bacterial ancestry, originating from within the bacterial phylum α-Proteobacteria (Alphaproteobacteria). Accordingly, the endosymbiont hypothesis—the idea that the mitochondrion evolved from a bacterial progenitor via symbiosis within an essentially eukaryotic host cell—has assumed the status of a theory. Yet mitochondrial genome evolution has taken radically different pathways in diverse eukaryotic lineag...

  2. The Research of Image Encryption Algorithm Based on Chaos Cellular Automata

    Directory of Open Access Journals (Sweden)

    Shuiping Zhang

    2012-02-01

    Full Text Available The Research presents an image encryption algorithm which bases on chaotic cellular automata. This algorithm makes use of features that extreme sensitivity of chaotic system to initial conditions, the cellular automaton with a high degree of parallel processing. The encryption algorithm uses two-dimensional chaotic system to Encrypt image, Then establish a cellular automaton model on the initial encrypted image. Encryption key of this algorithm is made up of the initial value by the two-dimensional chaotic systems, parameters, two-dimensional cellular automata local evolution rules f and iterations n. Experimental results shows that the algorithm has features that high efficiency, better security, sensitivity to the key and so on.

  3. Cellular phones: are they detrimental?

    Science.gov (United States)

    Salama, Osama E; Abou El Naga, Randa M

    2004-01-01

    The issue of possible health effects of cellular phones is very much alive in the public's mind where the rapid increase in the number of the users of cell phones in the last decade has increased the exposure of people to the electromagnetic fields (EMFs). Health consequences of long term use of mobile phones are not known in detail but available data indicates the development of non specific annoying symptoms on acute exposure to mobile phone radiations. In an attempt to determine the prevalence of such cell phones associated health manifestations and the factors affecting their occurrence, a cross sectional study was conducted in five randomly selected faculties of Alexandria University. Where, 300 individuals including teaching staff, students and literate employee were equally allocated and randomly selected among the five faculties. Data about mobile phone's users and their medical history, their pattern of mobile usage and the possible deleterious health manifestations associated with cellular phone use was collected. The results revealed 68% prevalence of mobile phone usage, nearly three quarters of them (72.5%) were complainers of the health manifestations. They suffered from headache (43%), earache (38.3%), sense of fatigue (31.6%), sleep disturbance (29.5%), concentration difficulty (28.5%) and face burning sensation (19.2%). Both univariate and multivariate analysis were consistent in their findings. Symptomatic users were found to have significantly higher frequency of calls/day, longer call duration and longer total duration of mobile phone usage/day than non symptomatic users. For headache both call duration and frequency of calls/day were the significant predicting factors for its occurrence (chi2 = 18.208, p = 0.0001). For earache, in addition to call duration, the longer period of owning the mobile phone were significant predictors (chi2 = 16.996, p = 0.0002). Sense of fatigue was significantly affected by both call duration and age of the user

  4. The mammary cellular hierarchy and breast cancer

    OpenAIRE

    Oakes, Samantha R.; Gallego-Ortega, David; Ormandy, Christopher J.

    2014-01-01

    Advances in the study of hematopoietic cell maturation have paved the way to a deeper understanding the stem and progenitor cellular hierarchy in the mammary gland. The mammary epithelium, unlike the hematopoietic cellular hierarchy, sits in a complex niche where communication between epithelial cells and signals from the systemic hormonal milieu, as well as from extra-cellular matrix, influence cell fate decisions and contribute to tissue homeostasis. We review the discovery, definition and ...

  5. A radiation measurement study on cellular phone

    International Nuclear Information System (INIS)

    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)

  6. Predicting Cellular Growth from Gene Expression Signatures

    OpenAIRE

    Dunham, Maitreya J.; Troyanskaya, Olga G.; Airoldi, Edoardo; Broach, James R.; Caudy, Amy A.; Gresham, David; Botstein, David; Huttenhower, Curtis; Lu, Charles

    2009-01-01

    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 metazo...

  7. Cellular structure in system of interacting particles

    OpenAIRE

    Lev, Bohdan

    2008-01-01

    The general description of formation the cellular structure in the system of interacting particles is proposed. Interactions between particles are presumably well-understood and the phase transition in which can be studied in the scale of particle resolution. We presented analytical results of possible cellular structures for suspension of colloidal particles, in system particles immersed in liquid crystal and gravitational system. We have shown that cellular structure formation can occur in ...

  8. Radiation, nitric oxide and cellular death

    International Nuclear Information System (INIS)

    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

  9. Autophagy and mitophagy in cellular damage control

    Directory of Open Access Journals (Sweden)

    Jianhua Zhang

    2013-01-01

    Full Text Available Autophagy and mitophagy are important cellular processes that are responsible for breaking down cellular contents, preserving energy and safeguarding against accumulation of damaged and aggregated biomolecules. This graphic review gives a broad summary of autophagy and discusses examples where autophagy is important in controlling protein degradation. In addition we highlight how autophagy and mitophagy are involved in the cellular responses to reactive species and mitochondrial dysfunction. The key signaling pathways for mitophagy are described in the context of bioenergetic dysfunction.

  10. Endosymbiosis and Eukaryotic Cell Evolution.

    Science.gov (United States)

    Archibald, John M

    2015-10-01

    Understanding the evolution of eukaryotic cellular complexity is one of the grand challenges of modern biology. It has now been firmly established that mitochondria and plastids, the classical membrane-bound organelles of eukaryotic cells, evolved from bacteria by endosymbiosis. In the case of mitochondria, evidence points very clearly to an endosymbiont of α-proteobacterial ancestry. The precise nature of the host cell that partnered with this endosymbiont is, however, very much an open question. And while the host for the cyanobacterial progenitor of the plastid was undoubtedly a fully-fledged eukaryote, how - and how often - plastids moved from one eukaryote to another during algal diversification is vigorously debated. In this article I frame modern views on endosymbiotic theory in a historical context, highlighting the transformative role DNA sequencing played in solving early problems in eukaryotic cell evolution, and posing key unanswered questions emerging from the age of comparative genomics. PMID:26439354

  11. The cellular particle swarm optimization algorithm

    International Nuclear Information System (INIS)

    This work presents a variant of the Particle Swarm Optimization (PSO) original algorithm, the Cellular-PSO. Inspired by the cellular Genetic Algorithm (GA), particles in Cellular-PSO are arranged into a matrix of cells interconnected according to a given topology. Such topology defines particle's neighborhood, inside which social adaptation may occur. As a consequence, population diversity is increased and the optimization process becomes more efficient and robust. The proposed Cellular-PSO has been applied to the nuclear reactor core design optimization problem and comparative experiments demonstrated that it is superior to the standard PSO. (author)

  12. Optimized Cellular Core for Rotorcraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Patz Materials and Technologies proposes to develop a unique structural cellular core material to improve mechanical performance, reduce platform weight and lower...

  13. Cellular Auxin Transport in Algae

    Science.gov (United States)

    Zhang, Suyun; van Duijn, Bert

    2014-01-01

    The phytohormone auxin is one of the main directors of plant growth and development. In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. Algae are a group of relatively simple, autotrophic, photosynthetic organisms that share many features with land plants. In particular, Charophyceae (a taxon of green algae) are closest ancestors of land plants. In the study of auxin function, transport and its evolution, the algae form an interesting research target. Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies.

  14. Illuminating cellular physiology: recent developments.

    Science.gov (United States)

    Brovko, Lubov Y; Griffiths, Mansel W

    2007-01-01

    Bioluminescent methods are gaining more and more attention among scientists due to their sensitivity, selectivity and simplicity; coupled with the fact that the bioluminescence can be monitored both in vitro and in vivo. Since the discovery of bioluminescence in the 19th century, enzymes involved in the bioluminescent process have been isolated and cloned. The bioluminescent reactions in several different organisms have also been fully characterized and used as reporters in a wide variety of biochemical assays. From the 1990s it became clear that bioluminescence can be detected and quantified directly from inside a living cell. This gave rise to numerous possibilities for the in vivo monitoring of intracellular processes non-invasively using bioluminescent molecules as reporters. This review describes recent developments in the area of bioluminescent imaging for cell biology. Newly developed imaging methods allow transcriptional/translational regulation, signal transduction, protein-protein interaction, oncogenic transformation, cell and protein trafficking, and target drug action to be monitored in vivo in real-time with high temporal and spatial resolution; thus providing researchers with priceless information on cellular functions. Advantages and limitations of these novel bioluminescent methods are discussed and possible future developments identified. PMID:17725230

  15. Efficiency of cellular information processing

    CERN Document Server

    Barato, Andre C; Seifert, Udo

    2014-01-01

    We show that a rate of conditional Shannon entropy reduction, characterizing the learning of an internal process about an external process, is bounded by the thermodynamic entropy production. This approach allows for the definition of an informational efficiency that can be used to study cellular information processing. We analyze three models of increasing complexity inspired by the E. coli sensory network, where the external process is an external ligand concentration jumping between two values. We start with a simple model for which ATP must be consumed so that a protein inside the cell can learn about the external concentration. With a second model for a single receptor we show that the rate at which the receptor learns about the external environment can be nonzero even without any dissipation inside the cell since chemical work done by the external process compensates for this learning rate. The third model is more complete, also containing adaptation. For this model we show inter alia that a bacterium i...

  16. Cellular scaling rules for the brain of afrotherians

    Science.gov (United States)

    Neves, Kleber; Ferreira, Fernanda M.; Tovar-Moll, Fernanda; Gravett, Nadine; Bennett, Nigel C.; Kaswera, Consolate; Gilissen, Emmanuel; Manger, Paul R.; Herculano-Houzel, Suzana

    2014-01-01

    Quantitative analysis of the cellular composition of rodent, primate and eulipotyphlan brains has shown that non-neuronal scaling rules are similar across these mammalian orders that diverged about 95 million years ago, and therefore appear to be conserved in evolution, while neuronal scaling rules appear to be free to vary in evolution in a clade-specific manner. Here we analyze the cellular scaling rules that apply to the brain of afrotherians, believed to be the first clade to radiate from the common eutherian ancestor. We find that afrotherians share non-neuronal scaling rules with rodents, primates and eulipotyphlans, as well as the coordinated scaling of numbers of neurons in the cerebral cortex and cerebellum. Afrotherians share with rodents and eulipotyphlans, but not with primates, the scaling of number of neurons in the cortex and in the cerebellum as a function of the number of neurons in the rest of the brain. Afrotheria also share with rodents and eulipotyphlans the neuronal scaling rules that apply to the cerebral cortex. Afrotherians share with rodents, but not with eulipotyphlans nor primates, the neuronal scaling rules that apply to the cerebellum. Importantly, the scaling of the folding index of the cerebral cortex with the number of neurons in the cerebral cortex is not shared by either afrotherians, rodents, or primates. The sharing of some neuronal scaling rules between afrotherians and rodents, and of some additional features with eulipotyphlans and primates, raise the interesting possibility that these shared characteristics applied to the common eutherian ancestor. In turn, the clade-specific characteristics that relate to the distribution of neurons along the surface of the cerebral cortex and to its degree of gyrification suggest that these characteristics compose an evolutionarily plastic suite of features that may have defined and distinguished mammalian groups in evolution. PMID:24596544

  17. 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.

  18. CHEMICAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Melvin

    1965-06-01

    How did life come to be on the surface of the earth? Darwin himself recognized that his basic idea of evolution by variation and natural selection must be a continuous process extending backward in time through that period in which the first living things arose and into the period of 'Chemical Evolution' which preceded it. We are approaching the examination of these events by two routes. One is to seek for evidence in the ancient rocks of the earth which were laid down prior to that time in which organisms capable of leaving their skeletons in the rocks to be fossilized were in existence. This period is sometime prior to approximately 600 million years ago. The earth is believed to have taken its present form approximately 4700 million years ago. We have found in rocks whose age is about 1000 million years certain organic molecules which are closely related to the green pigment of plants, chlorophyll. This seems to establish that green plants were already fluorishing prior to that time. We have now found in rocks of still greater age, namely, 2500 million years, the same kinds of molecules mentioned above which can be attributed to the presence of living organisms. If these molecules are as old as the rocks, we have thus shortened the time available for the generation of the complex biosynthetic sequences which give rise to these specific hydrocarbons (polyisoprenoids) to less than 2000 million years.

  19. Pulsed feedback defers cellular differentiation.

    Directory of Open Access Journals (Sweden)

    Joe H Levine

    2012-01-01

    Full Text Available Environmental signals induce diverse cellular differentiation programs. In certain systems, cells defer differentiation for extended time periods after the signal appears, proliferating through multiple rounds of cell division before committing to a new fate. How can cells set a deferral time much longer than the cell cycle? Here we study Bacillus subtilis cells that respond to sudden nutrient limitation with multiple rounds of growth and division before differentiating into spores. A well-characterized genetic circuit controls the concentration and phosphorylation of the master regulator Spo0A, which rises to a critical concentration to initiate sporulation. However, it remains unclear how this circuit enables cells to defer sporulation for multiple cell cycles. Using quantitative time-lapse fluorescence microscopy of Spo0A dynamics in individual cells, we observed pulses of Spo0A phosphorylation at a characteristic cell cycle phase. Pulse amplitudes grew systematically and cell-autonomously over multiple cell cycles leading up to sporulation. This pulse growth required a key positive feedback loop involving the sporulation kinases, without which the deferral of sporulation became ultrasensitive to kinase expression. Thus, deferral is controlled by a pulsed positive feedback loop in which kinase expression is activated by pulses of Spo0A phosphorylation. This pulsed positive feedback architecture provides a more robust mechanism for setting deferral times than constitutive kinase expression. Finally, using mathematical modeling, we show how pulsing and time delays together enable "polyphasic" positive feedback, in which different parts of a feedback loop are active at different times. Polyphasic feedback can enable more accurate tuning of long deferral times. Together, these results suggest that Bacillus subtilis uses a pulsed positive feedback loop to implement a "timer" that operates over timescales much longer than a cell cycle.

  20. Immune cellular response to HPV: current concepts

    Directory of Open Access Journals (Sweden)

    Maria Alice Guimarães Gonçalves

    2004-02-01

    Full Text Available Although cellular immunity is essential for the elimination of human papillomavirus (HPV, the mechanisms involved are still poorly understood. We summarize the main mechanisms involved in cellular immune response to infections caused by HPV. Immunotherapies for HPV-related cancers require the disruption of T-cell response control mechanisms, associated with the stimulation of the Th1 cytokine response.

  1. Mechanisms of cellular transformation by carcinogenic agents

    International Nuclear Information System (INIS)

    This book contains 14 chapters. Some of the chapter titles are: DNA Modification by Chemical Carcinogens; Role of DNA Lesions and Repair in the Transformation of Human Cells; The Induction and Regulation of Radiogenic Transformation In Vitro: Cellular and Molecular Mechanisms; Cellular Transformation by Adenoviruses; and The fos Gene

  2. Recent development of cellular manufacturing systems

    Indian Academy of Sciences (India)

    P K Arora; A Haleem; M K Singh

    2013-06-01

    Cellular manufacturing system has been proved a vital approach for batch and job shop production systems. Group technology has been an essential tool for developing a cellular manufacturing system. The paper aims to discuss various cell formation techniques and highlights the significant research work done in past over the years and attempts to points out the gap in research.

  3. Mechanisms of cellular transformation by carcinogenic agents

    Energy Technology Data Exchange (ETDEWEB)

    Grunberger, D.; Goff, S.P.

    1987-01-01

    This book contains 14 chapters. Some of the chapter titles are: DNA Modification by Chemical Carcinogens; Role of DNA Lesions and Repair in the Transformation of Human Cells; The Induction and Regulation of Radiogenic Transformation In Vitro: Cellular and Molecular Mechanisms; Cellular Transformation by Adenoviruses; and The fos Gene.

  4. LMS filters for cellular CDMA overlay

    OpenAIRE

    Wang, J.

    1996-01-01

    This paper extends and complements previous research we have performed on the performance of nonadaptive narrowband suppression filters when used in cellular CDMA overlay situations. In this paper, an adaptive LMS filter is applied to cellular CDMA overlay situations in order to reject narrowband interference.

  5. From Cnn Dynamics to Cellular Wave Computers

    Science.gov (United States)

    Roska, Tamas

    2013-01-01

    Embedded in a historical overview, the development of the Cellular Wave Computing paradigm is presented, starting from the standard CNN dynamics. The theoretical aspects, the physical implementation, the innovation process, as well as the biological relevance are discussed in details. Finally, the latest developments, the physical versus virtual cellular machines, as well as some open questions are presented.

  6. Four Dimensional (4-D BioChemInfoPhysics Models of Cardiac Cellular and Sub-Cellular Vibrations (Oscillations

    Directory of Open Access Journals (Sweden)

    Chang-Hua Zou

    2009-01-01

    Full Text Available Problem statement: Cardiovascular Diseases (CVD continued to be the leading cause of death. Failure or abnormal cardiac cellular or sub-cellular vibrations (oscillations could lead failure or abnormal heart beats that could cause CVD. Understanding the mechanisms of the vibrations (oscillations could help to prevent or to treat the diseases. Scientists have studied the mechanisms for more than 100 years. To our knowledge, the mechanisms are still unclear today. In this investigation, based on published data or results, conservation laws of the momentum as well as the energy, in views of biology, biochemistry, informatics and physics (BioChemInfoPhysics, we proposed our models of cardiac cellular and sub-cellular vibrations (oscillations of biological components, such as free ions in Biological Fluids (BF, Biological Membranes (BM, Ca++H+ (Ca++ and Na+K+ ATPases, Na+Ca++ exchangers (NCX, Ca++ carriers and myosin heads. Approach: Our models were described with 4-D (x, y, z, t or r, ?, z, t momentum transfer equations in mathematical physics. Results: The momentum transfer equations were solved with free and forced, damped, un-damped and over-damped, vibrations (oscillations. The biological components could be modeled as resonators or vibrators (oscillators, such as liquid plasmas, membranes, active springs, passive springs and active swings. Conclusion: We systematically provided new insights of automation (ignition and maintain, transportation, propagation and orientation of the cardiac cellular and sub-cellular vibrations (oscillations and resonances, with our BioChemInfoPhysics models of 4-D momentum transfer equations. Our modeling results implied: Auto-rhythmic cells (Sinoatrial Node Cells (SANC, Atrioventricular Node Cells (AVNC, Purkinje fibers, non-Auto-rhythmic ventricular myocytes and their Sarcoplasmic Reticulums (SR work as Biological Liquid Plasma Resonators (BLPR. The resonators were

  7. Molecular evolution of scorpion a-toxins--Accelerated substitutions and functional divergence

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Scorpion α-toxins are a family of toxic proteins with similar scaffold, but possess divergent pharmacological properties.Analysis of cDNA sequences reveals that the numbers of nucleotide substitutions per site (K) for 5' and 3' UTRs are smaller than those per synonymous site (Ks) for the mature peptide-coding sequences, whereas the numbers of nucleotide substitutions per nonsynonymous site (Ka) are close to or larger than Ks values for relevant pairs of cDNAs. These results, together with phylogenetic analysis, indicate that scorpion a-toxins have evolved by accelerated substitutions in the mature toxin regions. In addition, the 15 amino acids, absolutely conserved in all the scorpion α-toxins described so far, are mostly located in molecular interior, which may be involved in structural constraints for stabilizing the CSαβ fold in evolution of these molecules. Four hot spot mutation sites in the molecular surface are found to dis tribute in the putative functional regions of α-toxins, suggesting that positive Darwinian selection drives the accelerated evolution of scorpion α-toxins. These findings reasonably explain the relationship between three-dimensional structure conservation and functional divergence of scorpion α-toxins and are of important value in guiding us in our engineering experiments to obtain higher affinity ligands to Na+ channels.

  8. Evolution of a microbial nitrilase gene family: a comparative and environmental genomics study

    Directory of Open Access Journals (Sweden)

    Eads Jonathan R

    2005-08-01

    Full Text Available Abstract Background Completed genomes and environmental genomic sequences are bringing a significant contribution to understanding the evolution of gene families, microbial metabolism and community eco-physiology. Here, we used comparative genomics and phylogenetic analyses in conjunction with enzymatic data to probe the evolution and functions of a microbial nitrilase gene family. Nitrilases are relatively rare in bacterial genomes, their biological function being unclear. Results We examined the genetic neighborhood of the different subfamily genes and discovered conserved gene clusters or operons associated with specific nitrilase clades. The inferred evolutionary transitions that separate nitrilases which belong to different gene clusters correlated with changes in their enzymatic properties. We present evidence that Darwinian adaptation acted during one of those transitions and identified sites in the enzyme that may have been under positive selection. Conclusion Changes in the observed biochemical properties of the nitrilases associated with the different gene clusters are consistent with a hypothesis that those enzymes have been recruited to a novel metabolic pathway following gene duplication and neofunctionalization. These results demonstrate the benefits of combining environmental genomic sampling and completed genomes data with evolutionary and biochemical analyses in the study of gene families. They also open new directions for studying the functions of nitrilases and the genes they are associated with.

  9. The Universe as a Cellular System

    CERN Document Server

    Aragón-Calvo, Miguel A

    2014-01-01

    Cellular systems are observed everywhere in nature, from crystal domains in metals, soap froth and cucumber cells to the network of cosmological voids. Surprisingly, despite their disparate scale and origin all cellular systems follow certain scaling laws relating their geometry, topology and dynamics. Using a cosmological N-body simulation we found that the Cosmic Web, the largest known cellular system, follows the same scaling relations seen elsewhere in nature. Our results extend the validity of scaling relations in cellular systems by over 30 orders of magnitude in scale with respect to previous studies. The dynamics of cellular systems can be used to interpret local observations such as the local velocity anomaly as the result of a collapsing void in our cosmic backyard. Moreover, scaling relations depend on the curvature of space, providing an independent measure of geometry.

  10. Modelling for Forest Fire Evolution Based on the Energy Accumulation and Release

    OpenAIRE

    Fan Yang; Qing Yang; Xingxing Liu; Pan Wang

    2015-01-01

    Forest fire evolution plays an important role in the decision-making of controlling the forest fire. This paper aims to simulate the dynamics of the forest fire spread using a cellular automaton approach. Having analyzed the characteristics and evolution of forest fires, a simulation model for the forest fire evolution based on the energy accumulation and release is proposed. And, taking Australia's catastrophic forest fire in 2009 as an example, the fire’s evolution closely to the reality is...

  11. An analogy between the evolution of drug resistance in bacterial communities and malignant tissues

    OpenAIRE

    Lambert, Guillaume; Estévez-Salmeron, Luis; Oh, Steve; Liao, David; Emerson, Beverly M.; Tlsty, Thea D.; Austin, Robert H.

    2011-01-01

    Cancer cells rapidly evolve drug resistance through somatic evolution and, in order to continue growth in the metastatic phase, violate the organism-wide consensus of regulated growth and beneficial communal interactions. We suggest that there is a fundamental mechanistic connection between the rapid evolution of resistance to chemotherapy in cellular communities within malignant tissues and the rapid evolution of antibiotic resistance in bacterial communities. We propose that this evolution ...

  12. Community Evolution

    CERN Document Server

    Bródka, Piotr; Kazienko, Przemysław

    2016-01-01

    The continuous interest in the social network area contributes to the fast development of this field. The new possibilities of obtaining and storing data facilitate deeper analysis of the entire social network, extracted social groups and single individuals as well. One of the most interesting research topic is the network dynamics and dynamics of social groups in particular, it means analysis of group evolution over time. It is the natural step forward after social community extraction. Having communities extracted, appropriate knowledge and methods for dynamic analysis may be applied in order to identify changes as well as to predict the future of all or some selected groups. Furthermore, knowing the most probably change of a given group some additional steps may be performed in order to change this predicted future according to specific needs. Such ability would be a powerful tool in the hands of human resource managers, personnel recruitment, marketing, telecommunication companies, etc.

  13. PROBLEMAS ALTRUISTAS DARWINIANOS Darwinian Altruistic Issues

    Directory of Open Access Journals (Sweden)

    JORGE MARTÍNEZ-CONTRERAS

    Full Text Available Darwin propuso en 1871 que preferiría descender de un mono que de los -salvajes-. El mono es un babuino Papio hamadryas que, en un relato de Brehm, salva a un infante de una jauría. Los -salvajes- son los fueguinos a los que visitó en el año 1833. ¿Por qué Darwin, a pesar de haber sido tan buen observador del comportamiento animal, no pudo discernir en qué consistía la sociedad de cazadores-recolectores de los cuatro grupos humanos de Tierra del Fuego? Esto es lo que tratamos de dilucidar en este trabajo.In 1871 Darwin mentioned that he would rather descent from a monkey than from -savages-. The monkey in question was a Papio hamadryas baboon that, in Brehm's account, saves an infant from a pack of dogs. The -savages- were the now disappeared Fuegians, whom he visited in the Beagle's voyage, in 1833. Why Darwin through he was a very good observer of animal behavior could not discern the social characteristics of the four hunter-gatherer human societies he knew in Tierra del Fuego? Our aim in this work is to try to elucidate this dilemma.

  14. Towards a Darwinian approach to Mathematics

    OpenAIRE

    De Cruz, Helen

    2006-01-01

    In the past decades, recent paradigm shifts in ethology, psychology, and the social sciences have given rise to various new disciplines like cognitive ethology and evolutionary psychology. These disciplines use concepts and theories of evolutionary biology to understand and explain the design, function and origin of the brain. I shall argue that there are several good reasons why this approach could also apply to human mathematical abilities. I will review evidence from various disciplines (c...

  15. Markers of cellular senescence. Telomere shortening as a marker of cellular senescence.

    Science.gov (United States)

    Bernadotte, Alexandra; Mikhelson, Victor M; Spivak, Irina M

    2016-01-01

    The cellular senescence definition comes to the fact of cells irreversible proliferation disability. Besides the cell cycle arrest, senescent cells go through some morphological, biochemical, and functional changes which are the signs of cellular senescence. The senescent cells (including replicative senescence and stress-induced premature senescence) of all the tissues look alike. They are metabolically active and possess the set of characteristics in vitro and in vivo, which are known as biomarkers of aging and cellular senescence. Among biomarkers of cellular senescence telomere shortening is a rather elegant frequently used biomarker. Validity of telomere shortening as a marker for cellular senescence is based on theoretical and experimental data. PMID:26805432

  16. Estimating cellular network performance during hurricanes

    International Nuclear Information System (INIS)

    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.

  17. Om religion og evolution

    DEFF Research Database (Denmark)

    Geertz, Armin W.

    kulturens kausale virkning på den menneskelige kognition og ikke mindst den hominine evolution. Ud fra, hvad vi ved om den menneskelige evolution, ses det, at den hominine evolution har en dybde, som sjældent medtænkes i teorier og hypoteser om den menneskelige evolution. Den menneskelige evolution er...

  18. Macromolecular lesions and cellular radiation chemistry

    International Nuclear Information System (INIS)

    Our studies of the interaction of densely ionizing particles with macromolecules in the living cell may be divided into four parts: characterization of lesions to cellular DNA in the unmodified Bragg ionization curve; characterization of lesions to cellular DNA in the spread Bragg curve as used in radiation therapy; elucidation of the cellular radiation chemistry characteristic of high vs. low LET radiation qualities; and the introduction of novel techniques designed to give a better understanding of the fundamental properties of induction of lesions and their repair potentials in high LET radiation

  19. Integrating mitochondrial translation into the cellular context.

    Science.gov (United States)

    Richter-Dennerlein, Ricarda; Dennerlein, Sven; Rehling, Peter

    2015-10-01

    Mitochondrial-encoded subunits of the oxidative phosphorylation system assemble with nuclear-encoded subunits into enzymatic complexes. Recent findings showed that mitochondrial translation is linked to other mitochondrial functions, as well as to cellular processes. The supply of mitochondrial-encoded proteins is coordinated by the coupling of mitochondrial protein synthesis with assembly of respiratory chain complexes. MicroRNAs imported from the cytoplasm into mitochondria were, surprisingly, found to act as regulators of mitochondrial translation. In turn, translation in mitochondria controls cellular proliferation, and mitochondrial ribosomal subunits contribute to the cytoplasmic stress response. Thus, translation in mitochondria is apparently integrated into cellular processes. PMID:26535422

  20. Cellular and molecular mechanisms in kidney fibrosis

    Science.gov (United States)

    Duffield, Jeremy S.

    2014-01-01

    Fibrosis is a characteristic feature of all forms of chronic kidney disease. Deposition of pathological matrix in the interstitial space and within the walls of glomerular capillaries as well as the cellular processes resulting in this deposition are increasingly recognized as important factors amplifying kidney injury and accelerating nephron demise. Recent insights into the cellular and molecular mechanisms of fibrogenesis herald the promise of new therapies to slow kidney disease progression. This review focuses on new findings that enhance understanding of cellular and molecular mechanisms of fibrosis, the characteristics of myofibroblasts, their progenitors, and molecular pathways regulating both fibrogenesis and its resolution. PMID:24892703

  1. Nanomechanics of magnetically driven cellular endocytosis

    Science.gov (United States)

    Zablotskii, V.; Lunov, O.; Dejneka, A.; Jastrabík, L.; Polyakova, T.; Syrovets, T.; Simmet, Th.

    2011-10-01

    Being essential for many pharmacodynamic and pharmacokinetic processes and playing a crucial role in regulating substrate detachment that enables cellular locomotion, endocytotic mechanisms in many aspects still remain a mystery and therefore can hardly be controlled. Here, we report on experimental and modeling studies of the magnetically assisted endocytosis of functionalized superparamagnetic iron oxide nanoparticles by prostate cancer cells (PC-3) and characterize the time and force scales of the cellular uptake machinery. The results indicate how the cellular uptake rate could be controlled by applied magnetic field, membrane elasticity, and nanoparticle magnetic moment.

  2. Cellular Signaling Pathways and Their Clinical Reflections

    Directory of Open Access Journals (Sweden)

    N. Ceren Sumer-Turanligil

    2010-06-01

    Full Text Available Cellular signaling pathways have important roles in cellular growth, differentiation, inflammatory response and apoptosis and in regulation of cellular responses under various chemical stimulators. Different proteins which belong to these pathways may be exposed to loss-of-function or gain-of-function mutations; this may lead to many clinical phenotypes including primarily cancer. In this review information about basic working principles of these pathways and diseases related to them are included. [Archives Medical Review Journal 2010; 19(3.000: 180-191

  3. 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

  4. Cellular chain formation in Escherichia coli biofilms

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Klemm, Per

    2009-01-01

    In this study we report on a novel structural phenotype in Escherichia coli biofilms: cellular chain formation. Biofilm chaining in E. coli K-12 was found to occur primarily by clonal expansion, but was not due to filamentous growth. Rather, chain formation was the result of intercellular......; type I fimbriae expression significantly reduced cellular chain formation, presumably by steric hindrance. Cellular chain formation did not appear to be specific to E coli K-12. Although many urinary tract infection (UTI) isolates were found to form rather homogeneous, flat biofilms, three isolates...

  5. 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.

  6. Radiatively-Driven Cosmology in the Cellular Automaton Universe

    CERN Document Server

    Kurucz, R L

    2006-01-01

    This is an updated version of my paper "An outline of radiatively-driven cosmology" (Kurucz 2000). Here the Big Bang universe is replaced by a finite cellular automaton universe with no expansion (Kurucz 2006). The Big Bang is replaced by many little bangs spread throughout the universe that interact to produce the initial perturbations that form Population III stars, globular clusters, and galaxies, but no large-scale structure. These perturbations evolve into the universe as we now observe it. Evolution during the first billion years is controlled by radiation. Globular clusters are formed by radiatively-driven implosions, galaxies are formed by radiatively-triggered gravitational collapse of systems of globular clusters, and voids and the microwave background are formed by radiatively-driven expansion. After this period most of the strong radiation sources are exhausted and the universe relaxes into gravitational old age as we know it. To relieve the boredom we present the results of gedanken experiments (...

  7. Insect evolution.

    Science.gov (United States)

    Engel, Michael S

    2015-10-01

    It goes without saying that insects epitomize diversity, and with over a million documented species they stand out as one of the most remarkable lineages in the 3.5-billion-year history of life on earth (Figure 1). This reality is passé to even the layperson and is taken for granted in the same way none of us think much of our breathing as we go about our day, and yet insects are just as vital to our existence. Insects are simultaneously familiar and foreign to us, and while a small fraction are beloved or reviled, most are simply ignored. These inexorable evolutionary overachievers outnumber us all, their segmented body plan is remarkably labile, they combine a capacity for high rates of speciation with low levels of natural extinction, and their history of successes eclipses those of the more familiar ages of dinosaurs and mammals alike. It is their evolution - persisting over vast expanses of geological time and inextricably implicated in the diversification of other lineages - that stands as one of the most expansive subjects in biology. PMID:26439349

  8. Groupware requirements evolution patterns

    NARCIS (Netherlands)

    Pumareja, Dulce Trinidad

    2013-01-01

    Requirements evolution is a generally known problem in software development. Requirements are known to change all throughout a system's lifecycle. Nevertheless, requirements evolution is a poorly understood phenomenon. Most studies on requirements evolution focus on changes to written specifications

  9. A cellular automata-based mathematical model for thymocyte development.

    Directory of Open Access Journals (Sweden)

    Hallan Souza-e-Silva

    Full Text Available Intrathymic T cell development is an important process necessary for the normal formation of cell-mediated immune responses. Importantly, such a process depends on interactions of developing thymocytes with cellular and extracellular elements of the thymic microenvironment. Additionally, it includes a series of oriented and tunely regulated migration events, ultimately allowing mature cells to cross endothelial barriers and leave the organ. Herein we built a cellular automata-based mathematical model for thymocyte migration and development. The rules comprised in this model take into account the main stages of thymocyte development, two-dimensional sections of the normal thymic microenvironmental network, as well as the chemokines involved in intrathymic cell migration. Parameters of our computer simulations with further adjusted to results derived from previous experimental data using sub-lethally irradiated mice, in which thymus recovery can be evaluated. The model fitted with the increasing numbers of each CD4/CD8-defined thymocyte subset. It was further validated since it fitted with the times of permanence experimentally ascertained in each CD4/CD8-defined differentiation stage. Importantly, correlations using the whole mean volume of young normal adult mice revealed that the numbers of cells generated in silico with the mathematical model fall within the range of total thymocyte numbers seen in these animals. Furthermore, simulations made with a human thymic epithelial network using the same mathematical model generated similar profiles for temporal evolution of thymocyte developmental stages. Lastly, we provided in silico evidence that the thymus architecture is important in the thymocyte development, since changes in the epithelial network result in different theoretical profiles for T cell development/migration. This model likely can be used to predict thymocyte evolution following therapeutic strategies designed for recovery of the

  10. Intrinsic fluorescence of selenium nanoparticles for cellular imaging applications

    Science.gov (United States)

    Khalid, A.; Tran, Phong A.; Norello, Romina; Simpson, David A.; O'Connor, Andrea J.; Tomljenovic-Hanic, Snjezana

    2016-02-01

    Nanoparticles hold great potential in contributing to high-resolution bioimaging as well as for biomedical applications. Although, selenium (Se) nanoparticles (NPs) have been investigated owing to their potential roles in therapeutics, the imaging capability of these NPs has never been explored. This manuscript identifies the intrinsic fluorescence of Se NPs, which is highly beneficial for nanoscale imaging of biological structures. The emission of individual NPs and its evolution with time is explored. The photoluminescence spectra has revealed visible to near infrared emission for Se NPs. The work finally reflects on the role of this intrinsic fluorescence for in vitro imaging and tracking in fibroblast cells, without the need of any additional tags. This technique would overcome the limitations of the conventionally used methods of imaging with tagged fluorescent proteins and dyes, preventing possible adverse cellular effects or phototoxicity caused by the added fluorescent moieties.Nanoparticles hold great potential in contributing to high-resolution bioimaging as well as for biomedical applications. Although, selenium (Se) nanoparticles (NPs) have been investigated owing to their potential roles in therapeutics, the imaging capability of these NPs has never been explored. This manuscript identifies the intrinsic fluorescence of Se NPs, which is highly beneficial for nanoscale imaging of biological structures. The emission of individual NPs and its evolution with time is explored. The photoluminescence spectra has revealed visible to near infrared emission for Se NPs. The work finally reflects on the role of this intrinsic fluorescence for in vitro imaging and tracking in fibroblast cells, without the need of any additional tags. This technique would overcome the limitations of the conventionally used methods of imaging with tagged fluorescent proteins and dyes, preventing possible adverse cellular effects or phototoxicity caused by the added fluorescent

  11. The role of sirtuins in cellular homeostasis.

    Science.gov (United States)

    Kupis, Wioleta; Pałyga, Jan; Tomal, Ewa; Niewiadomska, Ewa

    2016-09-01

    Sirtuins are evolutionarily conserved nicotinamide adenine dinucleotide (NAD(+))-dependent lysine deacylases or ADP-ribosyltransferases. These cellular enzymes are metabolic sensors sensitive to NAD(+) levels that maintain physiological homeostasis in the animal and plant cells. PMID:27154583

  12. Optimized Cellular Core for Rotorcraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Patz Materials and Technologies has developed, produced and tested, as part of the Phase-I SBIR, a new form of composite cellular core material, named Interply...

  13. MILLIMETER-WAVE EMISSIVITY OF CELLULAR SYSTEMS

    Science.gov (United States)

    A general analysis has been presented of the millimeter-wave and farinfrared spectroscopic properties of in vivo cellular systems, and of the boson radiative equilibrium with steady-state nonequilibrium molecular systems. The frequency threshhold of spectroscopic properties assoc...

  14. A Matrix Construction of Cellular Algebras

    Institute of Scientific and Technical Information of China (English)

    Dajing Xiang

    2005-01-01

    In this paper, we give a concrete method to construct cellular algebras from matrix algebras by specifying certain fixed matrices for the data of inflations. In particular,orthogonal matrices can be chosen for such data.

  15. 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 such as...

  16. Vectorized multisite coding for hydrodynamic cellular automata

    International Nuclear Information System (INIS)

    Simulating eight lattices for Pomeau's cellular automata simultaneously through bit-per-bit operations, a vectorized Fortran program reached 30 million updates per second and per Cray YMP processor. They authors give the full innermost loops

  17. 47 CFR 22.911 - Cellular geographic service area.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Cellular geographic service area. 22.911... PUBLIC MOBILE SERVICES Cellular Radiotelephone Service § 22.911 Cellular geographic service area. The Cellular Geographic Service Area (CGSA) of a cellular system is the geographic area considered by the...

  18. Long-term dynamics of adaptive evolution in a globally important phytoplankton species to ocean acidification.

    Science.gov (United States)

    Schlüter, Lothar; Lohbeck, Kai T; Gröger, Joachim P; Riebesell, Ulf; Reusch, Thorsten B H

    2016-07-01

    Marine phytoplankton may adapt to ocean change, such as acidification or warming, because of their large population sizes and short generation times. Long-term adaptation to novel environments is a dynamic process, and phenotypic change can take place thousands of generations after exposure to novel conditions. We conducted a long-term evolution experiment (4 years = 2100 generations), starting with a single clone of the abundant and widespread coccolithophore Emiliania huxleyi exposed to three different CO2 levels simulating ocean acidification (OA). Growth rates as a proxy for Darwinian fitness increased only moderately under both levels of OA [+3.4% and +4.8%, respectively, at 1100 and 2200 μatm partial pressure of CO2 (Pco2)] relative to control treatments (ambient CO2, 400 μatm). Long-term adaptation to OA was complex, and initial phenotypic responses of ecologically important traits were later reverted. The biogeochemically important trait of calcification, in particular, that had initially been restored within the first year of evolution was later reduced to levels lower than the performance of nonadapted populations under OA. Calcification was not constitutively lost but returned to control treatment levels when high CO2-adapted isolates were transferred back to present-day control CO2 conditions. Selection under elevated CO2 exacerbated a general decrease of cell sizes under long-term laboratory evolution. Our results show that phytoplankton may evolve complex phenotypic plasticity that can affect biogeochemically important traits, such as calcification. Adaptive evolution may play out over longer time scales (>1 year) in an unforeseen way under future ocean conditions that cannot be predicted from initial adaptation responses. PMID:27419227

  19. A new mechanistic scenario for the origin and evolution of vertebrate cartilage.

    Directory of Open Access Journals (Sweden)

    Maria Cattell

    Full Text Available The appearance of cellular cartilage was a defining event in vertebrate evolution because it made possible the physical expansion of the vertebrate "new head". Despite its central role in vertebrate evolution, the origin of cellular cartilage has been difficult to understand. This is largely due to a lack of informative evolutionary intermediates linking vertebrate cellular cartilage to the acellular cartilage of invertebrate chordates. The basal jawless vertebrate, lamprey, has long been considered key to understanding the evolution of vertebrate cartilage. However, histological analyses of the lamprey head skeleton suggest it is composed of modern cellular cartilage and a putatively unrelated connective tissue called mucocartilage, with no obvious transitional tissue. Here we take a molecular approach to better understand the evolutionary relationships between lamprey cellular cartilage, gnathostome cellular cartilage, and lamprey mucocartilage. We find that despite overt histological similarity, lamprey and gnathostome cellular cartilage utilize divergent gene regulatory networks (GRNs. While the gnathostome cellular cartilage GRN broadly incorporates Runx, Barx, and Alx transcription factors, lamprey cellular cartilage does not express Runx or Barx, and only deploys Alx genes in certain regions. Furthermore, we find that lamprey mucocartilage, despite its distinctive mesenchymal morphology, deploys every component of the gnathostome cartilage GRN, albeit in different domains. Based on these findings, and previous work, we propose a stepwise model for the evolution of vertebrate cellular cartilage in which the appearance of a generic neural crest-derived skeletal tissue was followed by a phase of skeletal tissue diversification in early agnathans. In the gnathostome lineage, a single type of rigid cellular cartilage became dominant, replacing other skeletal tissues and evolving via gene cooption to become the definitive cellular cartilage of

  20. Has Human Evolution Stopped?

    OpenAIRE

    Templeton, Alan R.

    2010-01-01

    It has been argued that human evolution has stopped because humans now adapt to their environment via cultural evolution and not biological evolution. However, all organisms adapt to their environment, and humans are no exception. Culture defines much of the human environment, so cultural evolution has actually led to adaptive evolution in humans. Examples are given to illustrate the rapid pace of adaptive evolution in response to cultural innovations. These adaptive responses have important ...

  1. Dirac Cellular Automaton from Split-step Quantum Walk

    Science.gov (United States)

    Mallick, Arindam; Chandrashekar, C. M.

    2016-05-01

    Simulations of one quantum system by an other has an implication in realization of quantum machine that can imitate any quantum system and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using set of conditions which are not unique and are not always in implementable configuration on any other system. Dirac Cellular Automata (DCA) is one such model constructed for Dirac Hamiltonian (DH) in free quantum field theory. Here, starting from a split-step discrete-time quantum walk (QW) which is uniquely defined for experimental implementation, we recover the DCA along with all the fine oscillations in position space and bridge the missing connection between DH-DCA-QW. We will present the contribution of the parameters resulting in the fine oscillations on the Zitterbewegung frequency and entanglement. The tuneability of the evolution parameters demonstrated in experimental implementation of QW will establish it as an efficient tool to design quantum simulator and approach quantum field theory from principles of quantum information theory.

  2. Dirac Cellular Automaton from Split-step Quantum Walk.

    Science.gov (United States)

    Mallick, Arindam; Chandrashekar, C M

    2016-01-01

    Simulations of one quantum system by an other has an implication in realization of quantum machine that can imitate any quantum system and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using set of conditions which are not unique and are not always in implementable configuration on any other system. Dirac Cellular Automata (DCA) is one such model constructed for Dirac Hamiltonian (DH) in free quantum field theory. Here, starting from a split-step discrete-time quantum walk (QW) which is uniquely defined for experimental implementation, we recover the DCA along with all the fine oscillations in position space and bridge the missing connection between DH-DCA-QW. We will present the contribution of the parameters resulting in the fine oscillations on the Zitterbewegung frequency and entanglement. The tuneability of the evolution parameters demonstrated in experimental implementation of QW will establish it as an efficient tool to design quantum simulator and approach quantum field theory from principles of quantum information theory. PMID:27184159

  3. Dirac Cellular Automaton from Split-step Quantum Walk

    Science.gov (United States)

    Mallick, Arindam; Chandrashekar, C. M.

    2016-01-01

    Simulations of one quantum system by an other has an implication in realization of quantum machine that can imitate any quantum system and solve problems that are not accessible to classical computers. One of the approach to engineer quantum simulations is to discretize the space-time degree of freedom in quantum dynamics and define the quantum cellular automata (QCA), a local unitary update rule on a lattice. Different models of QCA are constructed using set of conditions which are not unique and are not always in implementable configuration on any other system. Dirac Cellular Automata (DCA) is one such model constructed for Dirac Hamiltonian (DH) in free quantum field theory. Here, starting from a split-step discrete-time quantum walk (QW) which is uniquely defined for experimental implementation, we recover the DCA along with all the fine oscillations in position space and bridge the missing connection between DH-DCA-QW. We will present the contribution of the parameters resulting in the fine oscillations on the Zitterbewegung frequency and entanglement. The tuneability of the evolution parameters demonstrated in experimental implementation of QW will establish it as an efficient tool to design quantum simulator and approach quantum field theory from principles of quantum information theory. PMID:27184159

  4. Line Complexity Asymptotics of Polynomial Cellular Automata

    OpenAIRE

    Stone, Bertrand

    2016-01-01

    Cellular automata are discrete dynamical systems that consist of patterns of symbols on a grid, which change according to a locally determined transition rule. In this paper, we will consider cellular automata that arise from polynomial transition rules, where the symbols in the automaton are integers modulo some prime $p$. We are principally concerned with the asymptotic behavior of the line complexity sequence $a_T(k)$, which counts, for each $k$, the number of coefficient strings of length...

  5. Cellular Restriction Factors of Feline Immunodeficiency Virus

    OpenAIRE

    Carsten Münk; Jörg Zielonka

    2011-01-01

    Lentiviruses are known for their narrow cell- and species-tropisms, which are determined by cellular proteins whose absence or presence either support viral replication (dependency factors, cofactors) or inhibit viral replication (restriction factors). Similar to Human immunodeficiency virus type 1 (HIV-1), the cat lentivirus Feline immunodeficiency virus (FIV) is sensitive to recently discovered cellular restriction factors from non-host species that are able to stop viruses from replicating...

  6. Cellular and molecular mechanisms in kidney fibrosis

    OpenAIRE

    Duffield, Jeremy S.

    2014-01-01

    Fibrosis is a characteristic feature of all forms of chronic kidney disease. Deposition of pathological matrix in the interstitial space and within the walls of glomerular capillaries as well as the cellular processes resulting in this deposition are increasingly recognized as important factors amplifying kidney injury and accelerating nephron demise. Recent insights into the cellular and molecular mechanisms of fibrogenesis herald the promise of new therapies to slow kidney disease progressi...

  7. Building mathematics cellular phone learning communities

    OpenAIRE

    Wajeeh M. Daher

    2011-01-01

    Researchers emphasize the importance of maintaining learning communities and environments. This article describes the building and nourishment of a learning community, one comprised of middle school students who learned mathematics out-of-class using the cellular phone. The building of the learning community was led by three third year pre-service teachers majoring in mathematics and computers. The pre-service teachers selected thirty 8th grade students to learn mathematics with the cellular ...

  8. Directed Percolation arising in Stochastic Cellular Automata

    OpenAIRE

    Regnault, Damien

    2008-01-01

    Cellular automata are both seen as a model of computation and as tools to model real life systems. Historically they were studied under synchronous dynamics where all the cells of the system are updated at each time step. Meanwhile the question of probabilistic dynamics emerges: on the one hand, to develop cellular automata which are capable of reliable computation even when some random errors occur; on the other hand, because synchronous dynamics is not a reasonable assumption to simulate re...

  9. Apoptotic regulation of epithelial cellular extrusion

    OpenAIRE

    De Andrade, Daniel,; Rosenblatt, Jody

    2011-01-01

    Cellular extrusion is a mechanism that removes dying cells from epithelial tissues to prevent compromising their barrier function. Extrusion occurs in all observed epithelia in vivo and can be modeled in vitro by inducing apoptosis in cultured epithelial monolayers. We established that actin and myosin form a ring that contracts in the surrounding cells that drives cellular extrusion. It is not clear, however, if all apoptotic pathways lead to extrusion and how apoptosis and extrusion are mol...

  10. Understanding cisplatin resistance using cellular models.

    OpenAIRE

    STORDAL, BRITTA KRISTINA

    2007-01-01

    PUBLISHED Many mechanisms of cisplatin resistance have been proposed from studies of cellular models of resistance including changes in cellular drug accumulation, detoxification of the drug, inhibition of apoptosis and repair of the DNA adducts. A series of resistant models were developed from CCRF-CEM leukaemia cells with increasing doses of cisplatin from 100 ng/ml. This produced increasing resistance up to 7-fold with a treatment dose of 1.6 ?g/ml. Cisplatin resistance i...

  11. Understanding cisplatin resistance using cellular models

    OpenAIRE

    Stordal, Britta; Davey, Mary

    2007-01-01

    Many mechanisms of cisplatin resistance have been proposed from studies of cellular models of resistance including changes in cellular drug accumulation, detoxification of the drug, inhibition of apoptosis and repair of the DNA adducts. A series of resistant models were developed from CCRF-CEM leukaemia cells with increasing doses of cisplatin from 100 ng/ml. This produced increasing resistance up to 7-fold with a treatment dose of 1.6 microg/ml. Cisplatin resistance in these cells correlated...

  12. Cellular Scaling Rules of Insectivore Brains

    OpenAIRE

    Sarko, Diana K.; Catania, Kenneth C.; Leitch, Duncan B.; Kaas, Jon H.; Herculano-Houzel, Suzana

    2009-01-01

    Insectivores represent extremes in mammalian body size and brain size, retaining various “primitive” morphological characteristics, and some species of Insectivora are thought to share similarities with small-bodied ancestral eutherians. This raises the possibility that insectivore brains differ from other taxa, including rodents and primates, in cellular scaling properties. Here we examine the cellular scaling rules for insectivore brains and demonstrate that insectivore scaling rules overla...

  13. Cellular scaling rules of insectivore brains

    OpenAIRE

    Sarko, Diana K.; Catania, Kenneth C.; Leitch, Duncan B.; Kaas, Jon H.; Suzana Herculano-Houzel

    2009-01-01

    Insectivores represent extremes in mammalian body size and brain size, retaining various “primitive” morphological characteristics, and some species of Insectivora are thought to share similarities with small-bodied ancestral eutherians. This raises the possibility that insectivore brains differ from other taxa, including rodents and primates, in cellular scaling properties. Here we examine the cellular scaling rules for insectivore brains and demonstrate that insectivore scaling ...

  14. Cellular scaling rules for primate brains

    OpenAIRE

    Herculano-Houzel, Suzana; Collins, Christine E.; Wong, Peiyan; Kaas, Jon H.

    2007-01-01

    Primates are usually found to have richer behavioral repertoires and better cognitive abilities than rodents of similar brain size. This finding raises the possibility that primate brains differ from rodent brains in their cellular composition. Here we examine the cellular scaling rules for primate brains and show that brain size increases approximately isometrically as a function of cell numbers, such that an 11× larger brain is built with 10× more neurons and ≈12× more nonneuronal cells of ...

  15. Stochastic Simulations on the Cellular Wave Computers

    OpenAIRE

    Ercsey-Ravasz, M.; Roska, T.; Néda, Z.

    2006-01-01

    The computational paradigm represented by Cellular Neural/nonlinear Networks (CNN) and the CNN Universal Machine (CNN-UM) as a Cellular Wave Computer, gives new perspectives for computational physics. Many numerical problems and simulations can be elegantly addressed on this fully parallelized and analogic architecture. Here we study the possibility of performing stochastic simulations on this chip. First a realistic random number generator is implemented on the CNN-UM, and then as an example...

  16. 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.

  17. Combining cellular automata and Monte Carlo algorithm to simulate three-dimensional grain growth

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; CHEN Ju-hua; GUO Pei-quan; ZHAO Ping

    2006-01-01

    A 3-D simulation of grain growth was conducted by utilizing cellular automata (CA) and Monte Carlo (MC) algorithm. In the simulating procedure, the three-dimensional space is divided into a large number of 2-D isometric planes. Then, each of the planes is divided into identical square cells. Finally, the cellular automata and Monte Carlo algorithm are combined together to simulate the grain growth. Through an evolutionary simulation, the recrystallized microstructure, the grain growth rate and the grain size distribution are acceptably predicted. The simulation routine can be used to simulate the real physical-metallurgy processes and to predict quantitative dynamic information of the evolution of microstructure. Further more, the method is also useful for optimization of materials properties by controlling the microstructure evolution.

  18. Self-organized Critical Model Of Biological Evolution

    OpenAIRE

    Chau, H. F.; Mak, L; Kwok, P. K.

    1994-01-01

    A punctuated equilibrium model of biological evolution with relative fitness between different species being the fundamental driving force of evolution is introduced. Mutation is modeled as a fitness updating cellular automaton process where the change in fitness after mutation follows a Gaussian distribution with mean $x>0$ and standard deviation $\\sigma$. Scaling behaviors are observed in our numerical simulation, indicating that the model is self-organized critical. Besides, the numerical ...

  19. Weighted Centroid Correction Localization in Cellular Systems

    Directory of Open Access Journals (Sweden)

    Rong-Zheng Li

    2011-01-01

    Full Text Available Problem statement: There is a large demand for wireless Location-Based Service (LBS and it is provided by many wireless cellular systems. In process of positioning a Mobile Station (MS, the computing speed is as important as the positioning accuracy and the algorithm should also be resistant to environmental influences. Approach: A new positioning method based on Weighted Centroid Correction Localization (WCCL for wireless cellular systems is introduced in this article. Firstly, referring to the receiving-state of an MS in cellular systems, it computes a weighted centroid of surrounding Base Stations (BSs as a rough approximate position of the MS. Then, according to the distances between the MS and the BSs being less or bigger than the computed distances between the BSs and the weighted centroid, it corrects the coordinate of the weighted centroid towards the directions of the BSs by moving it closer or farther in turn. Results: According to our experiments, WCCL improves the positioning accuracy, as well as to provide a better resistance to environmental influences. Conclusion: As a modified centroid-based localization algorithm, WCCL obtains weighting factors from the receiving-state of MS in multi-cells structured cellular systems and obtains a better positioning result in cellular systems without updating the network equipment. Therefore, for the cellular positioning problem, WCCL algorithm can be an alternate solution.

  20. Nudging Evolution?

    Directory of Open Access Journals (Sweden)

    Katharine N. Farrell

    2013-12-01

    Full Text Available This Special Feature, "Nudging Evolution? Critical Exploration of the Potential and Limitations of the Concept of Institutional Fit for the Study and Adaptive Management of Social-Ecological Systems," aims to contribute toward the development of social theory and social research methods for the study of social-ecological system dynamics. Our objective is to help strengthen the academic discourse concerning if, and if so, how, to what extent, and in what concrete ways the concept of institutional "fit" might play a role in helping to develop better understanding of the social components of interlinkages between the socioeconomic-cultural and ecological dynamics of social-ecological systems. Two clearly discernible patterns provide a map of this Special Feature: (1 One pattern is the authors' positions regarding the place and role of normativity within their studies and assessment of institutional fit. Some place this at the center of their studies, exploring phenomena endogenous to the process of defining what constitutes institutional fit, whereas others take the formation of norms as a phenomenon exogenous to their study. (2 Another pattern is the type of studies presented: critiques and elaborations of the theory, methods for judging qualities of fit, and/or applied case studies using the concept. As a body of work, these contributions highlight that self-understanding of social-ecological place, whether explicit or implicit, constitutes an important part of the study object, i.e., the role of institutions in social-ecological systems, and that this is, at the same time, a crucial point of reference for the scholar wishing to evaluate what constitutes institutional fit and how it might be brought into being.

  1. 'Biogeneric' developmental processes: drivers of major transitions in animal evolution.

    Science.gov (United States)

    Newman, Stuart A

    2016-08-19

    Using three examples drawn from animal systems, I advance the hypothesis that major transitions in multicellular evolution often involved the constitution of new cell-based materials with unprecedented morphogenetic capabilities. I term the materials and formative processes that arise when highly evolved cells are incorporated into mesoscale matter 'biogeneric', to reflect their commonality with, and distinctiveness from, the organizational properties of non-living materials. The first transition arose by the innovation of classical cell-adhesive cadherins with transmembrane linkage to the cytoskeleton and the appearance of the morphogen Wnt, transforming some ancestral unicellular holozoans into 'liquid tissues', and thereby originating the metazoans. The second transition involved the new capabilities, within a basal metazoan population, of producing a mechanically stable basal lamina, and of planar cell polarization. This gave rise to the eumetazoans, initially diploblastic (two-layered) forms, and then with the addition of extracellular matrices promoting epithelial-mesenchymal transformation, three-layered triploblasts. The last example is the fin-to-limb transition. Here, the components of a molecular network that promoted the development of species-idiosyncratic endoskeletal elements in gnathostome ancestors are proposed to have evolved to a dynamical regime in which they constituted a Turing-type reaction-diffusion system capable of organizing the stereotypical arrays of elements of lobe-finned fish and tetrapods. The contrasting implications of the biogeneric materials-based and neo-Darwinian perspectives for understanding major evolutionary transitions are discussed.This article is part of the themed issue 'The major synthetic evolutionary transitions'. PMID:27431521

  2. On the Influence of Selection Operators on Performances in Cellular Genetic Algorithms

    CERN Document Server

    Simoncini, David; Verel, Sébastien; Clergue, Manuel

    2008-01-01

    In this paper, we study the influence of the selective pressure on the performance of cellular genetic algorithms. Cellular genetic algorithms are genetic algorithms where the population is embedded on a toroidal grid. This structure makes the propagation of the best so far individual slow down, and allows to keep in the population potentially good solutions. We present two selective pressure reducing strategies in order to slow down even more the best solution propagation. We experiment these strategies on a hard optimization problem, the quadratic assignment problem, and we show that there is a value for of the control parameter for both which gives the best performance. This optimal value does not find explanation on only the selective pressure, measured either by take over time and diversity evolution. This study makes us conclude that we need other tools than the sole selective pressure measures to explain the performances of cellular genetic algorithms.

  3. 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.

  4. 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

  5. 47 CFR 22.970 - Unacceptable interference to part 90 non-cellular 800 MHz licensees from cellular radiotelephone...

    Science.gov (United States)

    2010-10-01

    .... Except as provided in 47 CFR 90.617(k), unacceptable interference to non-cellular part 90 licensees in...-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...

  6. Neighborhood Selection and Rules Identification for Cellular Automata: A Rough Sets Approach

    OpenAIRE

    Placzek, Bartlomiej

    2014-01-01

    In this paper a method is proposed which uses data mining techniques based on rough sets theory to select neighborhood and determine update rule for cellular automata (CA). According to the proposed approach, neighborhood is detected by reducts calculations and a rule-learning algorithm is applied to induce a set of decision rules that define the evolution of CA. Experiments were performed with use of synthetic as well as real-world data sets. The results show that the introduced method allow...

  7. Transfer-matrix DMRG for stochastic models: The Domany-Kinzel cellular automaton

    OpenAIRE

    Kemper, A.; Schadschneider, A.; Zittartz, J.

    2001-01-01

    We apply the transfer-matrix DMRG (TMRG) to a stochastic model, the Domany-Kinzel cellular automaton, which exhibits a non-equilibrium phase transition in the directed percolation universality class. Estimates for the stochastic time evolution, phase boundaries and critical exponents can be obtained with high precision. This is possible using only modest numerical effort since the thermodynamic limit can be taken analytically in our approach. We also point out further advantages of the TMRG o...

  8. 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

  9. Optimization of Inter Cellular Movement of Parts in Cellular Manufacturing System Using Genetic Algorithm

    OpenAIRE

    Siva Prasad Darla; C.D. Naiju; Polu Vidya Sagar; B. Venkat Likhit

    2014-01-01

    In the modern manufacturing environment, Cellular Manufacturing Systems (CMS) have gained greater importance in job shop or batch-type production to gain economic advantage similar to those of mass production. Successful implementation of CMS highly depends on the determination of part families; machine cells and minimizing inter cellular movement. This study considers machine component grouping problems namely inter-cellular movement and cell load variation by developing a mathematical model...

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

    Energy Technology Data Exchange (ETDEWEB)

    Han, Wenhu [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Gao, Yang, E-mail: gaoyang-00@mails.tsinghua.edu.cn [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Wang, Cheng [Beijing Institute of Technology, Beijing 100081 (China); Law, Chung K. [Center for Combustion Energy, Tsinghua University, Beijing 100084 (China); Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2015-10-15

    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.

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

    Science.gov (United States)

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

    2015-10-01

    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.

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

    International Nuclear Information System (INIS)

    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

  13. Optimization of Inter Cellular Movement of Parts in Cellular Manufacturing System Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Siva Prasad Darla

    2014-01-01

    Full Text Available In the modern manufacturing environment, Cellular Manufacturing Systems (CMS have gained greater importance in job shop or batch-type production to gain economic advantage similar to those of mass production. Successful implementation of CMS highly depends on the determination of part families; machine cells and minimizing inter cellular movement. This study considers machine component grouping problems namely inter-cellular movement and cell load variation by developing a mathematical model and optimizing the solution using Genetic Algorithm to arrive at a cell formation to minimize the inter-cellular movement and cell load variation. The results are presented with a numerical example.

  14. Directed Evolution of Enzymes for Industrial Biocatalysis.

    Science.gov (United States)

    Porter, Joanne L; Rusli, Rukhairul A; Ollis, David L

    2016-02-01

    Enzymes have the potential to catalyse a wide variety of chemical reactions. They are increasingly being sought as environmentally friendly and cost-effective alternatives to conventional catalysts used in industries ranging from bioremediation to applications in medicine and pharmaceutics. Despite the benefits, they are not without their limitations. Many naturally occurring enzymes are not suitable for use outside of their native cellular environments. However, protein engineering can be used to generate enzymes tailored for specific industrial applications. Directed evolution is particularly useful and can be employed even when lack of structural information impedes the use of rational design. The aim of this review is to provide an overview of current industrial applications of enzyme technology and to show how directed evolution can be used to modify and to enhance enzyme properties. This includes a brief discussion on library generation and a more detailed focus on library screening methods, which are critical to any directed evolution experiment. PMID:26661585

  15. Shape Memory Alloy-Based Periodic Cellular Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort will develop and demonstrate an innovative shape memory alloy (SMA) periodic cellular structural technology. Periodic cellular structures...

  16. On Technology and Evolution

    OpenAIRE

    Radovan, Mario

    2007-01-01

    Evolution creates structures of increasing order and power; in this process the stronger prevail over the weaker and carry the evolution further. Technology is an artificial creation that often threatens life and evolution conceived of as natural phenomena; but technology also supports life and it works together with evolution. However, there are claims that technology will do much more than that, and bring about an entirely new epoch of evolution. Technology will replace the fragile biologic...

  17. Protein Evolution in Cell and Tissue Development: Going Beyond Sequence and Transcriptional Analysis

    OpenAIRE

    Dickinson, Daniel J.; Weis, William I.; Nelson, W. James

    2011-01-01

    Studies of animal evolution often focus on sequence and transcriptional analysis, based on an assumption that the evolution of development is driven by changes in gene expression. We argue that biochemical and cell biological approaches are also required, because sequence-conserved proteins can have different biochemical, cellular and developmental properties.

  18. Spin Echo Studies on Cellular Water

    CERN Document Server

    Chang, D C; Nichols, B L; Rorschach, H E

    2014-01-01

    Previous studies indicated that the physical state of cellular water could be significantly different from pure liquid water. To experimentally investigate this possibility, we conducted a series of spin-echo NMR measurements on water protons in rat skeletal muscle. Our result indicated that the spin-lattice relaxation time and the spin-spin relaxation time of cellular water protons are both significantly shorter than that of pure water (by 4.3-fold and 34-fold, respectively). Furthermore, the spin diffusion coefficient of water proton is almost 1/2 of that of pure water. These data suggest that cellular water is in a more ordered state in comparison to pure water.

  19. Cellular Signaling in Health and Disease

    CERN Document Server

    Beckerman, Martin

    2009-01-01

    In today’s world, three great classes of non-infectious diseases – the metabolic syndromes (such as type 2 diabetes and atherosclerosis), the cancers, and the neurodegenerative disorders – have risen to the fore. These diseases, all associated with increasing age of an individual, have proven to be remarkably complex and difficult to treat. This is because, in large measure, when the cellular signaling pathways responsible for maintaining homeostasis and health of the body become dysregulated, they generate equally stable disease states. As a result the body may respond positively to a drug, but only for a while and then revert back to the disease state. Cellular Signaling in Health and Disease summarizes our current understanding of these regulatory networks in the healthy and diseased states, showing which molecular components might be prime targets for drug interventions. This is accomplished by presenting models that explain in mechanistic, molecular detail how a particular part of the cellular sign...

  20. Cellular automatons applied to gas dynamic problems

    Science.gov (United States)

    Long, Lyle N.; Coopersmith, Robert M.; McLachlan, B. G.

    1987-06-01

    This paper compares the results of a relatively new computational fluid dynamics method, cellular automatons, with experimental data and analytical results. This technique has been shown to qualitatively predict fluidlike behavior; however, there have been few published comparisons with experiment or other theories. Comparisons are made for a one-dimensional supersonic piston problem, Stokes first problem, and the flow past a normal flat plate. These comparisons are used to assess the ability of the method to accurately model fluid dynamic behavior and to point out its limitations. Reasonable results were obtained for all three test cases, but the fundamental limitations of cellular automatons are numerous. It may be misleading, at this time, to say that cellular automatons are a computationally efficient technique. Other methods, based on continuum or kinetic theory, would also be very efficient if as little of the physics were included.

  1. Infrared image enhancement using Cellular Automata

    Science.gov (United States)

    Qi, Wei; Han, Jing; Zhang, Yi; Bai, Lian-fa

    2016-05-01

    Image enhancement is a crucial technique for infrared images. The clear image details are important for improving the quality of infrared images in computer vision. In this paper, we propose a new enhancement method based on two priors via Cellular Automata. First, we directly learn the gradient distribution prior from the images via Cellular Automata. Second, considering the importance of image details, we propose a new gradient distribution error to encode the structure information via Cellular Automata. Finally, an iterative method is applied to remap the original image based on two priors, further improving the quality of enhanced image. Our method is simple in implementation, easy to understand, extensible to accommodate other vision tasks, and produces more accurate results. Experiments show that the proposed method performs better than other methods using qualitative and quantitative measures.

  2. Cellular automatons applied to gas dynamic problems

    Science.gov (United States)

    Long, Lyle N.; Coopersmith, Robert M.; Mclachlan, B. G.

    1987-01-01

    This paper compares the results of a relatively new computational fluid dynamics method, cellular automatons, with experimental data and analytical results. This technique has been shown to qualitatively predict fluidlike behavior; however, there have been few published comparisons with experiment or other theories. Comparisons are made for a one-dimensional supersonic piston problem, Stokes first problem, and the flow past a normal flat plate. These comparisons are used to assess the ability of the method to accurately model fluid dynamic behavior and to point out its limitations. Reasonable results were obtained for all three test cases, but the fundamental limitations of cellular automatons are numerous. It may be misleading, at this time, to say that cellular automatons are a computationally efficient technique. Other methods, based on continuum or kinetic theory, would also be very efficient if as little of the physics were included.

  3. Parametric study of double cellular detonation structure

    Science.gov (United States)

    Khasainov, B.; Virot, F.; Presles, H.-N.; Desbordes, D.

    2013-05-01

    A parametric numerical study is performed of a detonation cellular structure in a model gaseous explosive mixture whose decomposition occurs in two successive exothermic reaction steps with markedly different characteristic times. Kinetic and energetic parameters of both reactions are varied in a wide range in the case of one-dimensional steady and two-dimensional (2D) quasi-steady self-supported detonations. The range of governing parameters of both exothermic steps is defined where a "marked" double cellular structure exists. It is shown that the two-level cellular structure is completely governed by the kinetic parameters and the local overdrive ratio of the detonation front propagating inside large cells. Furthermore, since it is quite cumbersome to use detailed chemical kinetics in unsteady 2D case, the proposed work should help to identify the mixtures and the domain of their equivalence ratio where double detonation structure could be observed.

  4. Online isolation of defects in cellular nanocomputers

    Institute of Scientific and Technical Information of China (English)

    Teijiro Isokawa; Shin'ya Kowada; Ferdinand Peper; Naotake Kamiura; Nobuyuki Matsui

    2007-01-01

    Unreliability will be a major issue for computers built from components at nanometer scales.Thus,it's to be expected that such computers will need a high degree of defect-tolerance to overcome components' defects which have arisen during the process of manufacturing.This paper presents a novel approach to defect-tolerance that is especially geared towards nanocomputers based on asynchronous cellular automata.According to this approach,defective cells are detected and isolated by small configurations that move around randomly in cellular space.These configurations,called random flies,will attach to configurations that are static,which is typical for configurations that contain defective cells.On the other hand,dynamic configurations,like those that conduct computations,will not be isolated from the rest of the cellular space by the random flies,and will be able to continue their operations unaffectedly.

  5. Phagocytosis, a cellular immune response in insects

    Directory of Open Access Journals (Sweden)

    C Rosales

    2011-06-01

    Full Text Available Insects like many other organisms are exposed to a wide range of infectious agents. Defense against these agents is provided by innate immune systems, which include physical barriers, humoral responses, and cellular responses. The humoral responses are characterized by the production of antimicrobial peptides, while the cellular defense responses include nodulation, encapsulation, melanization and phagocytosis. The phagocytic process, whereby cells ingest large particles, is of fundamental importance for insects’ development and survival. Phagocytic cells recognize foreign particles through a series of receptors on their cell membrane for pathogen-associated molecules. These receptors in turn initiate a series of signaling pathways that instruct the cell to ingest and eventually destroy the foreign particle. This review describes insect innate humoral and cellular immune functions with emphasis on phagocytosis. Recent advances in our understanding of the phagocytic cell types in various insect species; the receptors involved and the signaling pathways activated during phagocytosis are discussed.

  6. Alleviate Cellular Congestion Through Opportunistic Trough Filling

    Directory of Open Access Journals (Sweden)

    Yichuan Wang

    2014-04-01

    Full Text Available The demand for cellular data service has been skyrocketing since the debut of data-intensive smart phones and touchpads. However, not all data are created equal. Many popular applications on mobile devices, such as email synchronization and social network updates, are delay tolerant. In addition, cellular load varies significantly in both large and small time scales. To alleviate network congestion and improve network performance, we present a set of opportunistic trough filling schemes that leverage the time-variation of network congestion and delay-tolerance of certain traffic in this paper. We consider average delay, deadline, and clearance time as the performance metrics. Simulation results show promising performance improvement over the standard schemes. The work shed lights on addressing the pressing issue of cellular overload.

  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. About the embedding of one dimensional cellular automata into hyperbolic cellular automata

    OpenAIRE

    Margenstern, Maurice

    2010-01-01

    In this paper, we look at two ways to implement determinisitic one dimensional cellular automata into hyperbolic cellular automata in three contexts: the pentagrid, the heptagrid and the dodecagrid, these tilings being classically denoted by $\\{5,4\\}$, $\\{7,3\\}$ and $\\{5,3,4\\}$ respectively.

  9. Dynamics of the multiplicity of cellular infection in a plant virus.

    Directory of Open Access Journals (Sweden)

    Serafín Gutiérrez

    Full Text Available Recombination, complementation and competition profoundly influence virus evolution and epidemiology. Since viruses are intracellular parasites, the basic parameter determining the potential for such interactions is the multiplicity of cellular infection (cellular MOI, i.e. the number of viral genome units that effectively infect a cell. The cellular MOI values that prevail in host organisms have rarely been investigated, and whether they remain constant or change widely during host invasion is totally unknown. Here, we fill this experimental gap by presenting the first detailed analysis of the dynamics of the cellular MOI during colonization of a host plant by a virus. Our results reveal ample variations between different leaf levels during the course of infection, with values starting close to 2 and increasing up to 13 before decreasing to initial levels in the latest infection stages. By revealing wide dynamic changes throughout a single infection, we here illustrate the existence of complex scenarios where the opportunity for recombination, complementation and competition among viral genomes changes greatly at different infection phases and at different locations within a multi-cellular host.

  10. Physicochemical evolution and positive selection of the gymnosperm matK proteins

    Indian Academy of Sciences (India)

    Da Cheng Hao; Jun Mu; Shi Lin Chen; Pei Gen Xiao

    2010-04-01

    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 from 27 Taxaceae and 12 Cephalotaxaceae species. matK sequences of 19 Pinaceae species were retrieved from GenBank. The phylogenetic tree was generated using conceptual-translated amino acid sequences. Selective influences were investigated using standard $d_{\\text{N}}/d_{\\text{S}}$ ratio methods and more sensitive techniques investigating the amino acid property changes resulting from nonsynonymous replacements in a phylogenetic context. Analyses revealed the presence of positive selection in matKs (N-terminal region, RT domain and domain X) of Taxaceae and Pinaceae, and found positive destabilizing selection in N-terminal region and RT domain of Cephalotaxaceae matK. Moreover, various amino acid properties were found to be influenced by destabilizing positive selection. Amino acid sites relating to these properties and to different secondary structures were found and have the potential to affect group II intron maturase function. Despite the evolutionary constraint on the rapidly evolving matK, this protein evolves under positive selection in gymnosperm. Several regions of matK have experienced molecular adaptation which fine-tunes maturase performance.

  11. Impact of genomics on the understanding of microbial evolution and classification: the importance of Darwin's views on classification.

    Science.gov (United States)

    Gupta, Radhey S

    2016-07-01

    Analyses of genome sequences, by some approaches, suggest that the widespread occurrence of horizontal gene transfers (HGTs) in prokaryotes disguises their evolutionary relationships and have led to questioning of the Darwinian model of evolution for prokaryotes. These inferences are critically examined in the light of comparative genome analysis, characteristic synapomorphies, phylogenetic trees and Darwin's views on examining evolutionary relationships. Genome sequences are enabling discovery of numerous molecular markers (synapomorphies) such as conserved signature indels (CSIs) and conserved signature proteins (CSPs), which are distinctive characteristics of different prokaryotic taxa. Based on these molecular markers, exhibiting high degree of specificity and predictive ability, numerous prokaryotic taxa of different ranks, currently identified based on the 16S rRNA gene trees, can now be reliably demarcated in molecular terms. Within all studied groups, multiple CSIs and CSPs have been identified for successive nested clades providing reliable information regarding their hierarchical relationships and these inferences are not affected by HGTs. These results strongly support Darwin's views on evolution and classification and supplement the current phylogenetic framework based on 16S rRNA in important respects. The identified molecular markers provide important means for developing novel diagnostics, therapeutics and for functional studies providing important insights regarding prokaryotic taxa. PMID:27279642

  12. 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'.

  13. Cellularity of certain quantum endomorphism algebras

    DEFF Research Database (Denmark)

    Andersen, Henning Haahr; Lehrer, Gus; Zhang, Ruibin

    2015-01-01

    For any ring A˜ such that Z[q±1∕2]⊆A˜⊆Q(q1∕2), let ΔA˜(d) be an A˜-form of the Weyl module of highest weight d∈N of the quantised enveloping algebra UA˜ of sl2. For suitable A˜, we exhibit for all positive integers r an explicit cellular structure for EndUA˜(ΔA˜(d)⊗r). This algebra and its cellul...... we independently recover the weight multiplicities of indecomposable tilting modules for Uζ(sl2) from the decomposition numbers of the endomorphism algebras, which are known through cellular theory....

  14. Rapid Cellular Turnover in Adipose Tissue

    OpenAIRE

    Alessandra Rigamonti; Kristen Brennand; Frank Lau; Cowan, Chad A.

    2011-01-01

    It was recently shown that cellular turnover occurs within the human adipocyte population. Through three independent experimental approaches — dilution of an inducible histone 2B-green fluorescent protein (H2BGFP), labeling with the cell cycle marker Ki67 and incorporation of BrdU — we characterized the degree of cellular turnover in murine adipose tissue. We observed rapid turnover of the adipocyte population, finding that 4.8% of preadipocytes are replicating at any time and that between 1–...

  15. Cellular effects of LRRK2 mutations

    OpenAIRE

    Cookson, Mark R.

    2012-01-01

    Mutations in leucine-rich repeat kinase 2 (LRRK2) are a relatively common cause of inherited Parkinson's disease (PD) but the mechanism(s) by which mutations lead to disease are poorly understood. Here, I will discuss what is known about LRRK2 in cellular models, focusing on specifically on assays that have been used to tease apart the effects of LRRK2 mutations on cellular phenotypes. LRRK2 expression has been suggested to cause loss of neuronal viability, although because it also has a stro...

  16. Toxicology and cellular effect of manufactured nanomaterials

    Science.gov (United States)

    Chen, Fanqing

    2014-07-22

    The increasing use of nanotechnology in consumer products and medical applications underlies the importance of understanding its potential toxic effects to people and the environment. Herein are described methods and assays to predict and evaluate the cellular effects of nanomaterial exposure. Exposing cells to nanomaterials at cytotoxic doses induces cell cycle arrest and increases apoptosis/necrosis, activates genes involved in cellular transport, metabolism, cell cycle regulation, and stress response. Certain nanomaterials induce genes indicative of a strong immune and inflammatory response within skin fibroblasts. Furthermore, the described multiwall carbon nanoonions (MWCNOs) can be used as a therapeutic in the treatment of cancer due to its cytotoxicity.

  17. Cellular basis of radiation-induced fibrosis

    International Nuclear Information System (INIS)

    Fibrosis is a common sequela of both cancer treatment by radiotherapy and accidental irradiation and has been described in many tissues including skin, lung, heart and liver. The underlying mechanisms of the radiation-induced fibrosis still remain to be resolved. In the present review we tried to illustrate the basic cellular mechanisms of radiation-induced fibrosis based on the newest findings arising from molecular radiobiology and cell biology. Based on these findings the cellular mechanism of radiation-induced fibrosis can be seen as a multicellular process involving various interacting cell systems in the target organ resulting in the fibrotic phenotype of the fibroblast/fibrocyte cell system

  18. The cellular decision between apoptosis and autophagy

    Directory of Open Access Journals (Sweden)

    Yong-Jun Fan

    2013-03-01

    Full Text Available Apoptosis and autophagy are important molecular processes that maintain organismal and cellular homeostasis, respectively. While apoptosis fulfills its role through dismantling damaged or unwanted cells, autophagy maintains cellular homeostasis through recycling selective intracellular organelles and molecules. Yet in some conditions, autophagy can lead to cell death. Apoptosis and autophagy can be stimulated by the same stresses. Emerging evidence indicates an interplay between the core proteins in both pathways, which underlies the molecular mechanism of the crosstalk between apoptosis and autophagy. This review summarizes recent literature on molecules that regulate both the apoptotic and autophagic processes.

  19. Chaotic behavior in the disorder cellular automata

    International Nuclear Information System (INIS)

    Disordered cellular automata (DCA) represent an intermediate class between elementary cellular automata and the Kauffman network. Recently, Rule 126 of DCA has been explicated: the system can be accurately described by a discrete probability function. However, a means of extending to other rules has not been developed. In this investigation, a density map of the dynamical behavior of DCA is formulated based on Rule 22 and other totalistic rules. The numerical results reveal excellent agreement between the model and original automata. Furthermore, the inhomogeneous situation is also discussed

  20. External insulation with cellular plastic materials

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt; Nielsen, Anker

    2014-01-01

    External thermal insulation composite systems (ETICS) can be used as extra insulation of existing buildings. The system can be made of cellular plastic materials or mineral wool. There is a European Technical guideline, ETAG 004, that describe the tests that shall be conducted on such systems....... This paper gives a comparison of systems with mineral wool and cellular plastic, based on experience from practice and literature. It is important to look at the details in the system and at long time stability of the properties such as thermal insulation, moisture and fire. Investigation of fire properties...

  1. On reversibility of cellular automata with periodic boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nobe, Atsushi [Graduate School of Engineering Science, Osaka University, Machikaneyama-cho 1-3, Toyonaka, Osaka 560-8531 (Japan); Yura, Fumitaka [Imai Quantum Computing and Information Project, ERATO, JST, Daini Hongo White Bldg 201, 5-28-3 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

    2004-06-04

    Reversibility of one-dimensional cellular automata with periodic boundary conditions is discussed. It is shown that there exist exactly 16 reversible elementary cellular automaton rules for infinitely many cell sizes by means of a correspondence between elementary cellular automaton and the de Bruijn graph. In addition, a sufficient condition for reversibility of three-valued and two-neighbour cellular automaton is given.

  2. 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....

  3. 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...

  4. Neutral evolution of Protein-protein interactions: a computational study using simple models

    OpenAIRE

    Simonson Thomas; Noirel Josselin

    2007-01-01

    Abstract Background Protein-protein interactions are central to cellular organization, and must have appeared at an early stage of evolution. To understand better their role, we consider a simple model of protein evolution and determine the effect of an explicit selection for Protein-protein interactions. Results In the model, viable sequences all have the same fitness, following the neutral evolution theory. A very simple, two-dimensional lattice representation of the protein structures is u...

  5. Cellular automata and self-organized criticality

    OpenAIRE

    Creutz, Michael

    1996-01-01

    Cellular automata provide a fascinating class of dynamical systems capable of diverse complex behavior. These include simplified models for many phenomena seen in nature. Among other things, they provide insight into self-organized criticality, wherein dissipative systems naturally drive themselves to a critical state with important phenomena occurring over a wide range of length and time scales.

  6. Cellular Automata Rules and Linear Numbers

    OpenAIRE

    Nayak, Birendra Kumar; Sahoo, Sudhakar; Biswal, Sagarika

    2012-01-01

    In this paper, linear Cellular Automta (CA) rules are recursively generated using a binary tree rooted at "0". Some mathematical results on linear as well as non-linear CA rules are derived. Integers associated with linear CA rules are defined as linear numbers and the properties of these linear numbers are studied.

  7. Building mathematics cellular phone learning communities

    Directory of Open Access Journals (Sweden)

    Wajeeh M. Daher

    2011-04-01

    Full Text Available Researchers emphasize the importance of maintaining learning communities and environments. This article describes the building and nourishment of a learning community, one comprised of middle school students who learned mathematics out-of-class using the cellular phone. The building of the learning community was led by three third year pre-service teachers majoring in mathematics and computers. The pre-service teachers selected thirty 8th grade students to learn mathematics with the cellular phone and be part of a learning community experimenting with this learning. To analyze the building and development stages of the cellular phone learning community, two models of community building stages were used; first the team development model developed by Tuckman (1965, second the life cycle model of a virtual learning community developed by Garber (2004. The research findings indicate that a learning community which is centered on a new technology has five 'life' phases of development: Pre-birth, birth, formation, performing, and maturity. Further, the research finding indicate that the norms that were encouraged by the preservice teachers who initiated the cellular phone learning community resulted in a community which developed, nourished and matured to be similar to a community of experienced applied mathematicians who use mathematical formulae to study everyday phenomena.

  8. Phosphoproteomics: new insights into cellular signaling

    OpenAIRE

    Mumby, Marc; Brekken, Deirdre

    2005-01-01

    Developments in the field of phosphoproteomics have been fueled by the need simultaneously to monitor many different phosphoproteins within the signaling networks that coordinate responses to changes in the cellular environment. This article presents a brief review of phosphoproteomics with an emphasis on the biological insights that have been derived so far.

  9. Cellular grafts in management of leucoderma

    Directory of Open Access Journals (Sweden)

    Mysore Venkataram

    2009-01-01

    Full Text Available Cellular grafting methods constitute important advances in the surgical management of leucoderma. Different methods such as noncultured epidermal suspensions, melanocyte cultures, and melanocyte-keratinocyte cultures have all been shown to be effective. This article reviews these methods.

  10. Cellular basis of memory for addiction.

    Science.gov (United States)

    Nestler, Eric J

    2013-12-01

    DESPITE THE IMPORTANCE OF NUMEROUS PSYCHOSOCIAL FACTORS, AT ITS CORE, DRUG ADDICTION INVOLVES A BIOLOGICAL PROCESS: the ability of repeated exposure to a drug of abuse to induce changes in a vulnerable brain that drive the compulsive seeking and taking of drugs, and loss of control over drug use, that define a state of addiction. Here, we review the types of molecular and cellular adaptations that occur in specific brain regions to mediate addiction-associated behavioral abnormalities. These include alterations in gene expression achieved in part via epigenetic mechanisms, plasticity in the neurophysiological functioning of neurons and synapses, and associated plasticity in neuronal and synaptic morphology mediated in part by altered neurotrophic factor signaling. Each of these types of drug-induced modifications can be viewed as a form of "cellular or molecular memory." Moreover, it is striking that most addiction-related forms of plasticity are very similar to the types of plasticity that have been associated with more classic forms of "behavioral memory," perhaps reflecting the finite repertoire of adaptive mechanisms available to neurons when faced with environmental challenges. Finally, addiction-related molecular and cellular adaptations involve most of the same brain regions that mediate more classic forms of memory, consistent with the view that abnormal memories are important drivers of addiction syndromes. The goal of these studies which aim to explicate the molecular and cellular basis of drug addiction is to eventually develop biologically based diagnostic tests, as well as more effective treatments for addiction disorders. PMID:24459410

  11. Functional continuity: did field-induced oriented aperiodic constraints at Life's origin aid its sequence-based evolution?

    Science.gov (United States)

    Mitra-Delmotte, G.; Mitra, A. N.

    2014-04-01

    A non-biological analog undergoing Darwinian-like evolution could have enhanced the probability of many crucial independent bottom-up emergent steps, engendered within its premises, and smoothen the inanimate-animate transition. Now, the higher-level environment-mutable DNA sequences influence the lower-level pattern of oriented templates (enzymes, lipid membranes, RNA) in the organized cell matrix and hence their associated substrate-dynamics; note how templates are akin to local fields, kinetically constraining reactant orientations. Since the lowerlevel is likely the more primitive of the two (rather than Cairns-Smith's "readily available" rigid clay crystal sequence-based replicators as a memory-like basis for slowly mutating predecessor-patterns enroute to complex RNA-based Darwinian evolution), a gradual thermodynamic-to-kinetic transition in an isotropic medium, is proposed as driven by some order-parameter --via "available" field-responsive dipolar colloid networks, as apart from bio-organics, mineral colloids also can display liquid crystal (LC) phases (see [1]). An access to solid-like orientational order in a fluid matrix suggests how aperiodic patterns can be influenced and sustained (a la homeostasis) via external inhomogeneous fields (e.g. magnetic rocks); this renders these cooperative networks with potential as confining host-media, whose environment-sensitivity can not only influence their sterically-coupled guest-substrates but also their network properties (the latter can enable 'functions' like spontaneous transport under non-equilibrium suggesting a natural basis for their selection by the environment). In turn LC systems could have been preceded by even simpler anisotropic fluid hosts, viz., external field-induced mineral magnetic nanoparticle (MNP) aggregates. Indeed, the capacity of an MNP to couple its magnetic and rotational d.o.f.s suggests how an environment-sensitive field-influenced network of interacting dipolar colloids close to

  12. Cellular dosimetry in nuclear medicine imaging: training

    International Nuclear Information System (INIS)

    The radionuclides used in nuclear medicine imaging emit not only diagnostically useful photons, but also energy electron emissions, responsible for dose heterogeneity at the cellular level. The mean dose delivered to the cell nucleus by electron emissions of 99mTc, 123I, 111In, 67Ga, and 201Tl, has been calculated, for the cell nucleus, a cytoplasmic and a cell membrane distribution of radioactivity. This model takes into account both the self-dose which results from the radionuclide located in the target cell, and the cross-dose, which comes from the surrounding cells. The results obtained by cellular dosimetry (Dcel) have been compared with those obtained with conventional dosimetry (Dconv), by assuming the same amount of radioactivity per cell. Cellular dosimetry shows, for a cytoplasmic and a cell membrane distributions of radioactivity, that the main contribution to the dose to the cell nucleus, comes from the surrounding cells. On the other hand, for a cell nucleus distribution of radioactivity, the self-dose is not negligible and may be the main contribution. The comparison between cellular and conventional dosimetry shows that Dcel/Dconv ratio ranges from 0.61 and O.89, in case of a cytoplasmic and a cell membrane distributions of radioactivity, depending on the radionuclide and cell dimensions. Thus, conventional dosimetry slightly overestimates the mean dose to the cell nucleus. On the other hand, Dcel/Dconv ranges from 1.1 to 75, in case of a cell nucleus distribution of radioactivity. Conventional dosimetry may strongly underestimates the absorbed dose to the nucleus, when radioactivity is located in the nucleus. The study indicates that in nuclear medicine imaging, cellular dosimetry may lead to a better understanding of biological effects of radiopharmaceuticals. (authors)

  13. Klotho-Dependent Cellular Transport Regulation.

    Science.gov (United States)

    Sopjani, M; Dërmaku-Sopjani, M

    2016-01-01

    Klotho is a transmembrane protein that in humans is encoded by the hKL gene. This protein is known to have aging suppressor effects and is predominantly expressed in the distal convoluted tubule of the kidney, parathyroid glands, and choroid plexus of the brain. The Klotho protein exists in both full-length membrane form and a soluble secreted form, which exerts numerous distinct functions. The extracellular domain of Klotho can be enzymatically cleaved off and released into the systemic circulation where it functions as β-glucuronidase and a hormone. Soluble Klotho is a multifunction protein present in the biological fluids including blood, urine, and cerebrospinal fluid of mammals. Klotho deficiency leads to multiple organ failure accompanied by early appearance of multiple age-related disorders and early death, whereas overexpression of Klotho results in the opposite effects. Klotho, an enzyme and hormone, has been reported to participate in the regulation of cellular transport processes across the plasma membrane either indirectly through inhibiting calcitriol (1,25(OH)2D3) formation or other mechanism, or by directly affecting transporter proteins, including ion channels, cellular carriers, and Na(+)/K(+)-ATPase. Accordingly, Klotho protein serves as a powerful regulator of cellular transport across the plasma membrane. Importantly, Klotho-dependent cellular transport regulation implies stimulatory or inhibitory effects. Klotho has been shown to play a key role in the regulation of multiple calcium and potassium ion channels, and various cellular carriers including the Na(+)-coupled cotransporters such as NaPi-IIa, NaPi-IIb, EAAT3, and EAAT4, CreaT1 as well as Na(+)/K(+)-ATPase. These regulations are parts of the antiaging function of Klotho, which will be discussing throughout this chapter. Clearly, further experimental efforts are required to investigate the effect of Klotho on other transport proteins and underlying molecular mechanisms by which Klotho

  14. Cellular glutathione prevents cytolethality of monomethylarsonic acid

    International Nuclear Information System (INIS)

    Inorganic arsenicals are clearly toxicants and carcinogens in humans. In mammals, including humans, inorganic arsenic often undergoes methylation, forming compounds such as monomethylarsonic acid (MMAsV) and dimethylarsinic acid (DMAsV). However, much less information is available on the in vitro toxic potential or mechanisms of these methylated arsenicals, especially MMAsV. We studied the molecular mechanisms of in vitro cytolethality of MMAsV using a rat liver epithelial cell line (TRL 1215). MMAsV was not cytotoxic in TRL 1215 cells even at concentrations exceeding 10 mM, but it became weakly cytotoxic and induced both necrotic and apoptotic cell death when cellular reduced glutathione (GSH) was depleted with the glutathione synthase inhibitor, L-buthionine-[S,R]-sulfoximine (BSO), or the glutathione reductase inhibitor, carmustine. Similar results were observed in the other mammalian cells, such as human skin TIG-112 cells, chimpanzee skin CRT-1609 cells, and mouse metallothionein (MT) positive and MT negative embryonic cells. Ethacrynic acid (EA), an inhibitor of glutathione S-transferase (GST) that catalyses GSH-substrate conjugation, also enhanced the cytolethality of MMAsV, but aminooxyacetic acid (AOAA), an inhibitor of β-lyase that catalyses the final breakdown of GSH-substrate conjugates, had no effect. Both the cellular GSH levels and the cellular GST activity were increased by the exposure to MMAsV in TRL 1215 cells. On the other hand, the addition of exogenous extracellular GSH enhanced the cytolethality of MMAsV, although cellular GSH levels actually prevented the cytolethality of combined MMAsV and exogenous GSH. These findings indicate that human arsenic metabolite MMAsV is not a highly toxic compound in mammalian cells, and the level of cellular GSH is critical to its eventual toxic effects

  15. Evolution, atmospheric oxygen, and complex disease.

    Science.gov (United States)

    Koch, Lauren Gerard; Britton, Steven L

    2007-08-20

    If evolution is an accurate statement of our biology, then disease must be tightly associated with its patterns. We considered selection for more optimal capacity for energy transfer as the most general pattern of evolution. From this, we propose that the etiology of complex disease is linked tightly to the evolutionary transition to cellular complexity that was afforded by the steep thermodynamic gradient of an oxygen atmosphere. In accord with this thesis, clinical studies reveal a strong statistical link between low aerobic capacity and all-cause mortality. In addition, large-scale unbiased network analyses demonstrate the pivotal role of oxygen metabolism in cellular function. The demonstration that multiple disease risks segregated during two-way artificial selection for low and high aerobic capacity in rats provides a remote test of these possible connections between evolution, oxygen metabolism, and complex disease. Even more broadly, an atmosphere with oxygen may be uniquely essential for development of complex life anywhere because oxygen is stable as a diatomic gas, is easily transported, and has a high electronegativity for participation in energy transfer via redox reactions. PMID:17473218

  16. Why cellular stress suppresses adipogenesis in skeletal tissue, but is ineffective in adipose tissue: Control of mesenchymal cell differentiation via integrin binding sites in extracellular matrices

    OpenAIRE

    Volloch, Vladimir; Olsen, Bjorn R.

    2013-01-01

    This Perspective addresses one of the major puzzles of adipogenesis in adipose tissue, namely its resistance to cellular stress. It introduces a concept of “density” of integrin binding sites in extracellular matrix, proposes a cellular signaling explanation for the observed effects of matrix elasticity and of cell shape on mesenchymal stem cell differentiation, and discusses how specialized integrin binding sites in collagen IV - containing matrices guard two pivotal physiological and evolut...

  17. Evolution of Bioreactors for Extracorporeal Liver Support

    Directory of Open Access Journals (Sweden)

    Vilkova Е.V.

    2014-03-01

    Full Text Available The development of effective extracorporeal liver support systems in acute and chronic hepatic failure for transplantology purposes and in toxic injuries is a promising direction in modern biomedical studies. Widely used techniques are based on physicochemical interactions of biological molecules, and able to perform a detoxification function only (hemodialysis, hemofiltration, hemodiafiltration, sorption, albumin dialysis, plasmapheresis. However, support systems combining both blood/plasma perfusion and cellular technologies to maintain metabolic, synthetic and regulatory hepatic functions — “artificial liver” systems — are being extensively developed in recent decades. The review describes the main types of cell lines cultured to occupy bioreactors, various technological concepts for bioreactor design (dynamic, static, scaffold-carriers as part of bioreactors (structure, biochemical composition. The study gives metabolic characteristics of a cellular component of “bioartificial liver”: nourishment, oxygen saturation. Various types of existing extracorporeal support systems, their evolution, and preclinical and clinical test results are presented.

  18. Models of Chemical Evolution

    OpenAIRE

    Matteucci, Francesca

    2003-01-01

    The basic principles underlying galactic chemical evolution and the most important results of chemical evolution models are discussed. In particular, the chemical evolution of the Milky Way galaxy, for which we possess the majority of observational constraints, is described. Then, it is shown how different star formation histories influence the chemical evolution of galaxies of different morphological type. Finally, the role of abundances and abundance ratios as cosmic clocks is emphasized an...

  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 toxicity (High-Throughput Cellular Assays for Modeling Toxicity in the Fish Reproductive System)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The purpose of this project is to adapt cellular in vitro assay systems of the rainbow trout pituitary, liver and ovary for high-throughput screening (HTS) of...

  1. Evolution & Diversity in Plants.

    Science.gov (United States)

    Pearson, Lorentz C.

    1988-01-01

    Summarizes recent findings that help in understanding how evolution has brought about the diversity of plant life that presently exists. Discusses basic concepts of evolution, diversity and classification, the three-line hypothesis of plant evolution, the origin of fungi, and the geologic time table. Included are 31 references. (CW)

  2. Cellular Dynamic Simulator: An Event Driven Molecular Simulation Environment for Cellular Physiology

    OpenAIRE

    Byrne, Michael J.; Waxham, M. Neal; Kubota, Yoshihisa

    2010-01-01

    In this paper, we present the Cellular Dynamic Simulator (CDS) for simulating diffusion and chemical reactions within crowded molecular environments. CDS is based on a novel event driven algorithm specifically designed for precise calculation of the timing of collisions, reactions and other events for each individual molecule in the environment. Generic mesh based compartments allow the creation / importation of very simple or detailed cellular structures that exist in a 3D environment. Multi...

  3. Synthesis of New Styrylquinoline Cellular Dyes, Fluorescent Properties, Cellular Localization and Cytotoxic Behavior

    OpenAIRE

    Rams-Baron, Marzena; Dulski, Mateusz; Mrozek-Wilczkiewicz, Anna; Korzec, Mateusz; Cieslik, Wioleta; Spaczyńska, Ewelina; Bartczak, Piotr; Ratuszna, Alicja; Polanski, Jaroslaw; Musiol, Robert

    2016-01-01

    New styrylquinoline derivatives with their photophysical constants are described. The synthesis was achieved via Sonogashira coupling using the newly developed heterogeneous nano-Pd/Cu catalyst system, which provides an efficient synthesis of high purity products. The compounds were tested in preliminary fluorescent microscopy studies to in order to identify their preferable cellular localization, which appeared to be in the lipid cellular organelles. The spectroscopic properties of the compo...

  4. Cellular and molecular basis of cerebellar development

    Science.gov (United States)

    Martinez, Salvador; Andreu, Abraham; Mecklenburg, Nora; Echevarria, Diego

    2013-01-01

    Historically, the molecular and cellular mechanisms of cerebellar development were investigated through structural descriptions and studying spontaneous mutations in animal models and humans. Advances in experimental embryology, genetic engineering, and neuroimaging techniques render today the possibility to approach the analysis of molecular mechanisms underlying histogenesis and morphogenesis of the cerebellum by experimental designs. Several genes and molecules were identified to be involved in the cerebellar plate regionalization, specification, and differentiation of cerebellar neurons, as well as the establishment of cellular migratory routes and the subsequent neuronal connectivity. Indeed, pattern formation of the cerebellum requires the adequate orchestration of both key morphogenetic signals, arising from distinct brain regions, and local expression of specific transcription factors. Thus, the present review wants to revisit and discuss these morphogenetic and molecular mechanisms taking place during cerebellar development in order to understand causal processes regulating cerebellar cytoarchitecture, its highly topographically ordered circuitry and its role in brain function. PMID:23805080

  5. Designing beauty the art of cellular automata

    CERN Document Server

    Martínez, Genaro

    2016-01-01

    This fascinating, colourful book offers in-depth insights and first-hand working experiences in the production of art works, using simple computational models with rich morphological behaviour, at the edge of mathematics, computer science, physics and biology. It organically combines ground breaking scientific discoveries in the theory of computation and complex systems with artistic representations of the research results. In this appealing book mathematicians, computer scientists, physicists, and engineers brought together marvelous and esoteric patterns generated by cellular automata, which are arrays of simple machines with complex behavior. Configurations produced by cellular automata uncover mechanics of dynamic patterns formation, their propagation and interaction in natural systems: heart pacemaker, bacterial membrane proteins, chemical rectors, water permeation in soil, compressed gas, cell division, population dynamics, reaction-diffusion media and self-organisation. The book inspires artists to tak...

  6. A Modified Sensitive Driving Cellular Automaton Model

    Institute of Scientific and Technical Information of China (English)

    GE Hong-Xia; DAI Shi-Qiang; DONG Li-Yun; LEI Li

    2005-01-01

    A modified cellular automaton model for traffic flow on highway is proposed with a novel concept about the variable security gap. The concept is first introduced into the original Nagel-Schreckenberg model, which is called the non-sensitive driving cellular automaton model. And then it is incorporated with a sensitive driving NaSch model,in which the randomization brake is arranged before the deterministic deceleration. A parameter related to the variable security gap is determined through simulation. Comparison of the simulation results indicates that the variable security gap has different influence on the two models. The fundamental diagram obtained by simulation with the modified sensitive driving NaSch model shows that the maximumflow are in good agreement with the observed data, indicating that the presented model is more reasonable and realistic.

  7. Mobile Node Localization in Cellular Networks

    Directory of Open Access Journals (Sweden)

    Yasir Malik

    2012-01-01

    Full Text Available Location information is the major component in location based applications. This information is used in different safety and service oriented applications to provide users with services according to their Geolocation. There are many approaches to locate mobile nodes in indoor and outdoor environments. In thispaper, we are interested in outdoor localization particularly in cellular networks of mobile nodes andpresented a localization method based on cell and user location information. Our localization method is based on hello message delay (sending and receiving time and coordinate information of Base Transceiver Station (BTSs. To validate our method across cellular network, we implemented and simulated our method in two scenarios i.e. maintaining database of base stations in centralize and distributed system. Simulation results show the effectiveness of our approach and its implementation applicability in telecommunication systems.

  8. Cellular automata in image processing and geometry

    CERN Document Server

    Adamatzky, Andrew; Sun, Xianfang

    2014-01-01

    The book presents findings, views and ideas on what exact problems of image processing, pattern recognition and generation can be efficiently solved by cellular automata architectures. This volume provides a convenient collection in this area, in which publications are otherwise widely scattered throughout the literature. The topics covered include image compression and resizing; skeletonization, erosion and dilation; convex hull computation, edge detection and segmentation; forgery detection and content based retrieval; and pattern generation. The book advances the theory of image processing, pattern recognition and generation as well as the design of efficient algorithms and hardware for parallel image processing and analysis. It is aimed at computer scientists, software programmers, electronic engineers, mathematicians and physicists, and at everyone who studies or develops cellular automaton algorithms and tools for image processing and analysis, or develops novel architectures and implementations of mass...

  9. Molecular features of cellular reprogramming and development.

    Science.gov (United States)

    Smith, Zachary D; Sindhu, Camille; Meissner, Alexander

    2016-03-01

    Differentiating somatic cells are progressively restricted to specialized functions during ontogeny, but they can be experimentally directed to form other cell types, including those with complete embryonic potential. Early nuclear reprogramming methods, such as somatic cell nuclear transfer (SCNT) and cell fusion, posed significant technical hurdles to precise dissection of the regulatory programmes governing cell identity. However, the discovery of reprogramming by ectopic expression of a defined set of transcription factors, known as direct reprogramming, provided a tractable platform to uncover molecular characteristics of cellular specification and differentiation, cell type stability and pluripotency. We discuss the control and maintenance of cellular identity during developmental transitions as they have been studied using direct reprogramming, with an emphasis on transcriptional and epigenetic regulation. PMID:26883001

  10. Stochastic Simulations on the Cellular Wave Computers

    CERN Document Server

    Ercsey-Ravasz, M; Neda, Z

    2006-01-01

    The computational paradigm represented by Cellular Neural/nonlinear Networks (CNN) and the CNN Universal Machine (CNN-UM) as a Cellular Wave Computer, gives new perspectives for computational physics. Many numerical problems and simulations can be elegantly addressed on this fully parallelized and analogic architecture. Here we study the possibility of performing stochastic simulations on this chip. First a realistic random number generator is implemented on the CNN-UM, and then as an example the two-dimensional Ising model is studied by Monte Carlo type simulations. The results obtained on an experimental version of the CNN-UM with 128 * 128 cells are in good agreement with the results obtained on digital computers. Computational time measurements suggests that the developing trend of the CNN-UM chips - increasing the lattice size and the number of local logic memories - will assure an important advantage for the CNN-UM in the near future.

  11. Cellular and Molecular Basis of Cerebellar Development

    Directory of Open Access Journals (Sweden)

    Salvador eMartinez

    2013-06-01

    Full Text Available Historically, the molecular and cellular mechanisms of cerebellar development were investigated through structural descriptions and studying spontaneous mutations in animal models and humans. Advances in experimental embryology, genetic engineering and neuroimaging techniques render today the possibility to approach the analysis of molecular mechanisms underlying histogenesis and morphogenesis of the cerebellum by experimental designs. Several genes and molecules were identified to be involved in the cerebellar plate regionalization, specification and differentiation of cerebellar neurons, as well as the establishment of cellular migratory routes and the subsequent neuronal connectivity. Indeed, pattern formation of the cerebellum requires the adequate orchestration of both key morphogenetic signals, arising from distinct brain regions, and local expression of specific transcription factors. Thus, the present review wants to revisit and discuss these morphogenetic and molecular mechanisms taking place during cerebellar development in order to understand causal processes regulating cerebellar cytoarchitecture, its highly topographically ordered circuitry and its role in brain function.

  12. Exponential Stability for Delayed Cellular Neural Networks

    Institute of Scientific and Technical Information of China (English)

    YANG Jin-xiang; ZHONG Shou-ming; YAN Ke-yu

    2005-01-01

    The exponential stability of the delayed cellular neural networks (DCNN's) is investigated. By dividing the network state variables into some parts according to the characters of the neural networks, some new sufficient conditions of exponential stability are derived via constructing a Liapunov function. It is shown that the conditions differ from previous ones. The new conditions, which are associated with some initial value, are represented by some blocks of the interconnection matrix.

  13. Spectrum sharing for future mobile cellular systems

    OpenAIRE

    Bennis, M

    2009-01-01

    Abstract Spectrum sharing has become a high priority research area over the past few years. The motivation behind this lies in the fact that the limited spectrum is currently inefficiently utilized. As recognized by the World radio communication conference (WRC)-07, the amount of identified spectrum is not large enough to support large bandwidths for a substantial number of operators. Therefore, it is paramount for future mobile cellular systems to share the frequency spectrum and coexist ...

  14. Clinical applications of cellular therapy products

    OpenAIRE

    Serpil Yanbakan

    2015-01-01

    Adult stem cells have the potential to differentiate into multiple cell types and have usage about lots of regenerative medicine research fields. Especially bone marrow-derived mesenchymal stem cells have a wide range of case presentation. New discoveries about stem cell biology will progress new options about cellular therapy products and isolation of different stem cell types will increase hope for treatment of important illness such as Parkinson’s disease, diabetes, malign brain tumors. It...

  15. Cellular Automata Studies of Vertical Silicon Devices

    OpenAIRE

    M. Saraniti; G. Zandler; G. Formicone; S. Goodnick

    1998-01-01

    We present systematic theoretical Cellular Automata (CA) studies of a novel nanometer scale Si device, namely vertically grown Metal Oxide Field Effect Transistors (MOSFET) with channel lengths between 65 and 120 nm. The CA simulations predict drain characteristics and output conductance as a function of gate length. The excellent agreement with available experimental data indicates a high quality oxide/semiconductor interface. Impact ionization is shown to be of minor importance. For inhomog...

  16. Mapping functional connectivity in cellular networks

    OpenAIRE

    Buibas, Marius

    2011-01-01

    My thesis is a collection of theoretical and practical techniques for mapping functional or effective connectivity in cellular neuronal networks, at the cell scale. This is a challenging scale to work with, primarily because of the difficulty in labeling and measuring the activities of networks of cells. It is also important as it underlies behavior, function, and complex diseases. I present methods to measure and quantify the dynamic activities of cells using the optical flow technique, whic...

  17. Integrating mitochondrial translation into the cellular context.

    OpenAIRE

    Richter-Dennerlein, R.; Dennerlein Sven, S.; Rehling, P

    2015-01-01

    Mitochondrial-encoded subunits of the oxidative phosphorylation system assemble with nuclear-encoded subunits into enzymatic complexes. Recent findings showed that mitochondrial translation is linked to other mitochondrial functions, as well as to cellular processes. The supply of mitochondrial- encoded proteins is coordinated by the coupling of mitochondrial protein synthesis with assembly of respiratory chain complexes. MicroRNAs imported from the cytoplasm into mitochondria were, surprisin...

  18. Stability of Stochastic Neutral Cellular Neural Networks

    Science.gov (United States)

    Chen, Ling; Zhao, Hongyong

    In this paper, we study a class of stochastic neutral cellular neural networks. By constructing a suitable Lyapunov functional and employing the nonnegative semi-martingale convergence theorem we give some sufficient conditions ensuring the almost sure exponential stability of the networks. The results obtained are helpful to design stability of networks when stochastic noise is taken into consideration. Finally, two examples are provided to show the correctness of our analysis.

  19. Cognitive resource management for heterogeneous cellular networks

    CERN Document Server

    Liu, Yongkang

    2014-01-01

    This Springer Brief focuses on cognitive resource management in heterogeneous cellular networks (Het Net) with small cell deployment for the LTE-Advanced system. It introduces the Het Net features, presents practical approaches using cognitive radio technology in accommodating small cell data relay and optimizing resource allocation and examines the effectiveness of resource management among small cells given limited coordination bandwidth and wireless channel uncertainty. The authors introduce different network characteristics of small cell, investigate the mesh of small cell access points in

  20. Cellular responses to environmental DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    This volume contains the proceedings of the conference entitled Cellular Responses to Environmental DNA Damage held in Banff,Alberta December 1--6, 1991. The conference addresses various aspects of DNA repair in sessions titled DNA repair; Basic Mechanisms; Lesions; Systems; Inducible Responses; Mutagenesis; Human Population Response Heterogeneity; Intragenomic DNA Repair Heterogeneity; DNA Repair Gene Cloning; Aging; Human Genetic Disease; and Carcinogenesis. Individual papers are represented as abstracts of about one page in length.