WorldWideScience

Sample records for analysis structural evolution

  1. Analysis of ribosomal protein gene structures: implications for intron evolution.

    Directory of Open Access Journals (Sweden)

    2006-03-01

    Full Text Available Many spliceosomal introns exist in the eukaryotic nuclear genome. Despite much research, the evolution of spliceosomal introns remains poorly understood. In this paper, we tried to gain insights into intron evolution from a novel perspective by comparing the gene structures of cytoplasmic ribosomal proteins (CRPs and mitochondrial ribosomal proteins (MRPs, which are held to be of archaeal and bacterial origin, respectively. We analyzed 25 homologous pairs of CRP and MRP genes that together had a total of 527 intron positions. We found that all 12 of the intron positions shared by CRP and MRP genes resulted from parallel intron gains and none could be considered to be "conserved," i.e., descendants of the same ancestor. This was supported further by the high frequency of proto-splice sites at these shared positions; proto-splice sites are proposed to be sites for intron insertion. Although we could not definitively disprove that spliceosomal introns were already present in the last universal common ancestor, our results lend more support to the idea that introns were gained late. At least, our results show that MRP genes were intronless at the time of endosymbiosis. The parallel intron gains between CRP and MRP genes accounted for 2.3% of total intron positions, which should provide a reliable estimate for future inferences of intron evolution.

  2. Morphotectonic analysis, structural evolution/pattern of a ...

    Indian Academy of Sciences (India)

    The present study focusses on the structural pattern and development of Giouchtas Mountain. Morphotectonic analyses in combination with field mapping and tectonic analysis were performed for this purpose. GIS techniques were used for mapping the spatial distribution of the geological features on the topographic relief ...

  3. An Analysis of the Structure and Evolution of Networks

    Science.gov (United States)

    Hua, Guangying

    2011-01-01

    As network research receives more and more attention from both academic researchers and practitioners, network analysis has become a fast growing field attracting many researchers from diverse fields such as physics, computer science, and sociology. This dissertation provides a review of theory and research on different real data sets from the…

  4. Brain structure evolution in a basal vertebrate clade: evidence from phylogenetic comparative analysis of cichlid fishes.

    Science.gov (United States)

    Gonzalez-Voyer, Alejandro; Winberg, Svante; Kolm, Niclas

    2009-09-21

    The vertebrate brain is composed of several interconnected, functionally distinct structures and much debate has surrounded the basic question of how these structures evolve. On the one hand, according to the 'mosaic evolution hypothesis', because of the elevated metabolic cost of brain tissue, selection is expected to target specific structures mediating the cognitive abilities which are being favored. On the other hand, the 'concerted evolution hypothesis' argues that developmental constraints limit such mosaic evolution and instead the size of the entire brain varies in response to selection on any of its constituent parts. To date, analyses of these hypotheses of brain evolution have been limited to mammals and birds; excluding Actinopterygii, the basal and most diverse class of vertebrates. Using a combination of recently developed phylogenetic multivariate allometry analyses and comparative methods that can identify distinct rates of evolution, even in highly correlated traits, we studied brain structure evolution in a highly variable clade of ray-finned fishes; the Tanganyikan cichlids. Total brain size explained 86% of the variance in brain structure volume in cichlids, a lower proportion than what has previously been reported for mammals. Brain structures showed variation in pair-wise allometry suggesting some degree of independence in evolutionary changes in size. This result is supported by variation among structures on the strength of their loadings on the principal size axis of the allometric analysis. The rate of evolution analyses generally supported the results of the multivariate allometry analyses, showing variation among several structures in their evolutionary patterns. The olfactory bulbs and hypothalamus were found to evolve faster than other structures while the dorsal medulla presented the slowest evolutionary rate. Our results favor a mosaic model of brain evolution, as certain structures are evolving in a modular fashion, with a small but

  5. Brain structure evolution in a basal vertebrate clade: evidence from phylogenetic comparative analysis of cichlid fishes

    Directory of Open Access Journals (Sweden)

    Kolm Niclas

    2009-09-01

    Full Text Available Abstract Background The vertebrate brain is composed of several interconnected, functionally distinct structures and much debate has surrounded the basic question of how these structures evolve. On the one hand, according to the 'mosaic evolution hypothesis', because of the elevated metabolic cost of brain tissue, selection is expected to target specific structures mediating the cognitive abilities which are being favored. On the other hand, the 'concerted evolution hypothesis' argues that developmental constraints limit such mosaic evolution and instead the size of the entire brain varies in response to selection on any of its constituent parts. To date, analyses of these hypotheses of brain evolution have been limited to mammals and birds; excluding Actinopterygii, the basal and most diverse class of vertebrates. Using a combination of recently developed phylogenetic multivariate allometry analyses and comparative methods that can identify distinct rates of evolution, even in highly correlated traits, we studied brain structure evolution in a highly variable clade of ray-finned fishes; the Tanganyikan cichlids. Results Total brain size explained 86% of the variance in brain structure volume in cichlids, a lower proportion than what has previously been reported for mammals. Brain structures showed variation in pair-wise allometry suggesting some degree of independence in evolutionary changes in size. This result is supported by variation among structures on the strength of their loadings on the principal size axis of the allometric analysis. The rate of evolution analyses generally supported the results of the multivariate allometry analyses, showing variation among several structures in their evolutionary patterns. The olfactory bulbs and hypothalamus were found to evolve faster than other structures while the dorsal medulla presented the slowest evolutionary rate. Conclusion Our results favor a mosaic model of brain evolution, as certain

  6. Frequency Analysis of Acoustic Emission Signal to Monitor Damage Evolution in Masonry Structures

    International Nuclear Information System (INIS)

    Masera, D; Bocca, P; Grazzini, A

    2011-01-01

    A crucial aspect in damage evaluation of masonry structures is the analysis of long-term behaviour and for this reason fatigue analysis has a great influence on safety assessment of this structures. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced and unreinforced masonry walls under variable amplitude and static loading has been carried out. During these tests, the AE signals were recorded. The AE signals were analysed using Fast Fourier Transform (FFT) to examine the frequency distribution of the micro and macro cracking. It possible to evaluate the evolution of the wavelength of the AE signal through the two characteristic peak in the AE spectrum signals and the wave speed of the P or S waves. This wavelength evolution can be represent the microcrak and macrocrack evolution in masonry walls. This procedure permits to estimate the fracture dimension characteristic in several loading condition and for several masonry reinforced condition.

  7. Evolution of energy structures

    International Nuclear Information System (INIS)

    Nifenecker, H.

    2005-01-01

    Because of the big inertia and long time constants of energy systems, their long-time behaviour is mainly determined by their present day state and by the trends of their recent evolution. For this reason, it is of prime importance to foresee the evolution of the different energy production sources which may play an important role in the future. A status of the world energy consumption and production is made first using the energy statistics of the IEA. Then, using the trends observed since 1973, the consequences of a simple extrapolation of these trends is examined. Finally, the scenarios of forecasting of energy structures, like those supplied by the International institute for applied systems analysis (IIASA) are discussed. (J.S.)

  8. Structural evolution of Ga-Ge-Te glasses by combined EXAFS and XPS analysis

    Energy Technology Data Exchange (ETDEWEB)

    Golovchak, R. [Department of Physics and Astronomy, Austin Peay State University, Clarksville, Tennessee 37044 (United States); Materials Science and Engineering Department, Lehigh University, 5 East Packer Avenue, Bethlehem, Pennsylvania 18015 (United States); Calvez, L.; Bureau, B. [Laboratoire des Verres et Ceramiques, Institut des Sciences Chimiques de Rennes, UMR-CNRS6226, University of Rennes 1 (France); Jain, H. [Materials Science and Engineering Department, Lehigh University, 5 East Packer Avenue, Bethlehem, Pennsylvania 18015 (United States)

    2013-08-07

    The structural evolution of Ga{sub x}Ge{sub y}Te{sub 100−x−y} glasses in the vicinity of GeTe{sub 4}-GaTe{sub 3} pseudo-binary tie-line is determined with high-resolution X-ray photoelectron (XPS) and extended X-ray absorption fine structure (EXAFS) spectroscopies. The analysis of XPS data is complicated by similar electronegativity values for the constituent chemical elements, but then the interpretation is facilitated by information from complementary EXAFS analysis of the structure around each element independently. The results show 4/4/2 coordination for Ga/Ge/Te atoms and absence of Ga(Ge)-Ge(Ga) bonds or extended Te clusters in significant concentrations within the whole range of studied composition. The observed structural features correlate well with the measured basic physical properties of Ga-containing germanium telluride glasses.

  9. Stellar structure and evolution

    International Nuclear Information System (INIS)

    Kippernhahn, R.; Weigert, A.

    1990-01-01

    This book introduces the theory of the internal structure of stars and their evolution in time. It presents the basic physics of stellar interiors, methods for solving the underlying equations, and the most important results necessary for understanding the wide variety of stellar types and phenomena. The evolution of stars is discussed from their birth through normal evolution to possibly spectacular final stages. Chapters on stellar oscillations and rotation are included

  10. Response and reliability analysis of nonlinear uncertain dynamical structures by the probability density evolution method

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.; Peng, Yongbo; Sichani, Mahdi Teimouri

    2016-01-01

    The paper deals with the response and reliability analysis of hysteretic or geometric nonlinear uncertain dynamical systems of arbitrary dimensionality driven by stochastic processes. The approach is based on the probability density evolution method proposed by Li and Chen (Stochastic dynamics...... of structures, 1st edn. Wiley, London, 2009; Probab Eng Mech 20(1):33–44, 2005), which circumvents the dimensional curse of traditional methods for the determination of non-stationary probability densities based on Markov process assumptions and the numerical solution of the related Fokker–Planck and Kolmogorov......–Feller equations. The main obstacle of the method is that a multi-dimensional convolution integral needs to be carried out over the sample space of a set of basic random variables, for which reason the number of these need to be relatively low. In order to handle this problem an approach is suggested, which...

  11. Structure and evolution of a European Parliament via a network and correlation analysis

    Science.gov (United States)

    Puccio, Elena; Pajala, Antti; Piilo, Jyrki; Tumminello, Michele

    2016-11-01

    We present a study of the network of relationships among elected members of the Finnish parliament, based on a quantitative analysis of initiative co-signatures, and its evolution over 16 years. To understand the structure of the parliament, we constructed a statistically validated network of members, based on the similarity between the patterns of initiatives they signed. We looked for communities within the network and characterized them in terms of members' attributes, such as electoral district and party. To gain insight on the nested structure of communities, we constructed a hierarchical tree of members from the correlation matrix. Afterwards, we studied parliament dynamics yearly, with a focus on correlations within and between parties, by also distinguishing between government and opposition. Finally, we investigated the role played by specific individuals, at a local level. In particular, whether they act as proponents who gather consensus, or as signers. Our results provide a quantitative background to current theories in political science. From a methodological point of view, our network approach has proven able to highlight both local and global features of a complex social system.

  12. Structure and evolution analysis of pollen receptor-like kinase in Zea mays and Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Dongxu; Wang, He; Irfan, Muhammad; Fan, Mingxia; Lin, Feng

    2014-08-01

    Receptor-like kinase (RLKs) is an important member in protein kinase family which is widely involved in plant growth, development and defense responses. It is significant to analyze the kinase structure and evolution of pollen RLKs in order to study their mechanisms. In our study, 64 and 73 putative pollen RLKs were chosen from maize and Arabidopsis. Phylogenetic analysis showed that the pollen RLKs were conservative and might had existed before divergence between monocot and dicot which were mainly concentrated in RLCK-VII and LRR-III two subfamilies. Chromosomal localization and gene duplication analysis showed the expansion of pollen RLKs were mainly caused by segmental duplication. By calculating Ka/Ks value of extracellular domain, intracellular domain and kinase domain in pollen RLKs, we found that the pollen RLKs duplicated genes had mainly experienced the purifying selection, while maize might have experienced weaker purifying selection. Meanwhile, extracellular domain might have experienced stronger diversifying selection than intracellular domain in both species. Estimation of duplication time showed that the duplication events of Arabidopsis have occurred approximately between 18 and 69 million years ago, compared to 0.67-170 million years ago of maize. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Combined Visualization of Structural and Metric Information for Software Evolution Analysis

    NARCIS (Netherlands)

    Gonzalez, Antonio; Theron, Roberto; Telea, Alexandru; Garcia, Francisco J.

    2009-01-01

    This paper discusses a proposal for the visualization of software evolution, with a focus on combining insight on changes that affect software metrics at project and class level, the project structure, the class hierarchy and the viewing of source code correlated to indirect class coupling. The

  14. Genre Analysis: Structural and Linguistic Evolution of the English-Medium Medical Research Article (1985-2004)

    Science.gov (United States)

    Li, Li-Juan; Ge, Guang-Chun

    2009-01-01

    This paper reports a corpus-based genre analysis of the structural and linguistic evolution of medical research articles (RAs) written in English. Towards that end, we analyzed the frequency of occurrence of the 11 moves identified by Nwogu (1997), of the three most frequently used verb tenses (simple past, simple present and present perfect) and…

  15. Structural analysis of the evolution of steroid specificity in the mineralocorticoid and glucocorticoid receptors

    Directory of Open Access Journals (Sweden)

    Ollikainen Noah

    2007-02-01

    Full Text Available Abstract Background The glucocorticoid receptor (GR and mineralocorticoid receptor (MR evolved from a common ancestor. Still not completely understood is how specificity for glucocorticoids (e.g. cortisol and mineralocorticoids (e.g. aldosterone evolved in these receptors. Results Our analysis of several vertebrate GRs and MRs in the context of 3D structures of human GR and MR indicates that with the exception of skate GR, a cartilaginous fish, there is a deletion in all GRs, at the position corresponding to Ser-949 in human MR. This deletion occurs in a loop before helix 12, which contains the activation function 2 (AF2 domain, which binds coactivator proteins and influences transcriptional activity of steroids. Unexpectedly, we find that His-950 in human MR, which is conserved in the MR in chimpanzee, orangutan and macaque, is glutamine in all teleost and land vertebrate MRs, including New World monkeys and prosimians. Conclusion Evolution of differences in the responses of the GR and MR to corticosteroids involved deletion in the GR of a residue corresponding to Ser-949 in human MR. A mutation corresponding to His-950 in human MR may have been important in physiological changes associated with emergence of Old World monkeys from prosimians.

  16. Stellar Structure and Evolution

    CERN Document Server

    Kippenhahn, Rudolf; Weiss, Achim

    2013-01-01

    This long-awaited second edition of the classical textbook on Stellar Structure and Evolution by Kippenhahn and Weigert is a thoroughly revised version of the original text. Taking into account modern observational constraints as well as additional physical effects such as mass loss and diffusion, Achim Weiss and Rudolf Kippenhahn have succeeded in bringing the book up to the state-of-the-art with respect to both the presentation of stellar physics and the presentation and interpretation of current sophisticated stellar models. The well-received and proven pedagogical approach of the first edition has been retained. The book provides a comprehensive treatment of the physics of the stellar interior and the underlying fundamental processes and parameters. The models developed to explain the stability, dynamics and evolution of the stars are presented and great care is taken to detail the various stages in a star’s life. Just as the first edition, which remained a standard work for more than 20 years after its...

  17. Evolution of energy structures; Evolution des structures energetiques

    Energy Technology Data Exchange (ETDEWEB)

    Nifenecker, H. [Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France)

    2005-07-01

    Because of the big inertia and long time constants of energy systems, their long-time behaviour is mainly determined by their present day state and by the trends of their recent evolution. For this reason, it is of prime importance to foresee the evolution of the different energy production sources which may play an important role in the future. A status of the world energy consumption and production is made first using the energy statistics of the IEA. Then, using the trends observed since 1973, the consequences of a simple extrapolation of these trends is examined. Finally, the scenarios of forecasting of energy structures, like those supplied by the International institute for applied systems analysis (IIASA) are discussed. (J.S.)

  18. Physical experiments and analysis on the generation and evolution of tsunami-induced turbulent coherent structures

    Science.gov (United States)

    Kalligeris, Nikos; Lynett, Patrick

    2017-11-01

    Numerous historical accounts describe the formation of ``whirpools'' inside ports and harbors during tsunami events, causing port operation disruptions. Videos from the Japan 2011 tsunami revealed complex nearshore flow patters, resulting from the interaction of tsunami-induced currents with the man-made coastline, and the generation of large eddies (or turbulent coherent structures) in numerous ports and harbors near the earthquake epicenter. The aim of this work is to study the generation and evolution of tsunami-induced turbulent coherent structures (TCS) in a well-controlled environment using realistic scaling. A physical configuration is created in the image of a port entrance at a scale of 1:27 and a small-amplitude, long period wave creates a transient flow through the asymmetric harbor channel. A separated region forms, which coupled with the transient flow, leads to the formation of a stable monopolar TCS. The surface flow is examined through mono- and stereo-PTV techniques to extract surface velocity vectors. Surface velocity maps and vortex flow profiles are used to study the experimental TCS generation and evolution, and characterize the TCS structure. Analytical tools are used to describe the TCS growth rate and kinetic energy decay. This work was funded by the National Science Foundation NEES Research program, with Award Number 1135026.

  19. Emergence, Analysis and Evolution of Structures Concepts and Strategies Across Disciplines

    CERN Document Server

    Lucas, Klaus

    2010-01-01

    The study of structures and structure generating processes is a common concern of all scientific and technical disciplines. The present volume presents an interdisciplinary investigation of the different methods of analysis and modelling which, while differing considerably in detail, usually have evolutionary adaption or development schemes at their core. The book naturally falls into three parts - a first part summarizing the transdisciplinary fundamentals, a second part discussing in detail case studies from various fields (production engineering, medicine, management, molecular biology, energy engineering, civil engineering, logistics, sociology, physics) and a shorter outlook on the transdisciplinary perspective.

  20. Analysis of the secondary structure of ITS transcripts in peritrich ciliates (Ciliophora, Oligohymenophorea): implications for structural evolution and phylogenetic reconstruction.

    Science.gov (United States)

    Sun, Ping; Clamp, John C; Xu, Dapeng

    2010-07-01

    Despite extensive previous morphological work, little agreement has been reached about phylogenetic relationships among peritrich ciliates, making it difficult to study the evolution of the group in a phylogenetic framework. In this study, the nucleotide characteristics and secondary structures of internal transcribed spacers 1 and 2 (ITS1 and ITS2) of 26 peritrich ciliates in 12 genera were analyzed. Information from secondary structures of ITS1 and ITS2 then was used to perform the first systematic study of ITS regions in peritrich ciliates, including one species of Rhabdostyla for which no sequence has been reported previously. Lengths of ITS1 and ITS2 sequences varied relatively little among taxa studied, but their G+C content was highly variable. General secondary structure models of ITS1 and ITS2 were proposed for peritrich ciliates and their reliability was assessed by compensatory base changes. The secondary structure of ITS1 contains three major helices in peritrich ciliates and deviations from this basic structure were found in all taxa examined. The core structure of peritrich ITS2 includes four helices, with helix III as the longest and containing a motif 5'-MAC versus GUK-3' at its apex as well as a YU-UY mismatch in helix II. In addition, the structural motifs of both ITS secondary structures were identified. Phylogenetic analyses using ITS data were performed by means of Bayesian inference, maximum likelihood and neighbor joining methods. Trees had a consistent branching pattern that included the following features: (1) Rhabdostyla always clustered with members of the family Vorticellidae, instead of members of the family Epistylididae, in which it is now classified on the basis of morphology. (2) The systematically questionable genus Ophrydium closely associated with Carchesium, forming a clearly defined, monophyletic group within the Vorticellidae. This supported the hypothesis derived from previous study based on small subunit rRNA gene sequences

  1. Combining protein sequence, structure, and dynamics: A novel approach for functional evolution analysis of PAS domain superfamily.

    Science.gov (United States)

    Dong, Zheng; Zhou, Hongyu; Tao, Peng

    2018-02-01

    PAS domains are widespread in archaea, bacteria, and eukaryota, and play important roles in various functions. In this study, we aim to explore functional evolutionary relationship among proteins in the PAS domain superfamily in view of the sequence-structure-dynamics-function relationship. We collected protein sequences and crystal structure data from RCSB Protein Data Bank of the PAS domain superfamily belonging to three biological functions (nucleotide binding, photoreceptor activity, and transferase activity). Protein sequences were aligned and then used to select sequence-conserved residues and build phylogenetic tree. Three-dimensional structure alignment was also applied to obtain structure-conserved residues. The protein dynamics were analyzed using elastic network model (ENM) and validated by molecular dynamics (MD) simulation. The result showed that the proteins with same function could be grouped by sequence similarity, and proteins in different functional groups displayed statistically significant difference in their vibrational patterns. Interestingly, in all three functional groups, conserved amino acid residues identified by sequence and structure conservation analysis generally have a lower fluctuation than other residues. In addition, the fluctuation of conserved residues in each biological function group was strongly correlated with the corresponding biological function. This research suggested a direct connection in which the protein sequences were related to various functions through structural dynamics. This is a new attempt to delineate functional evolution of proteins using the integrated information of sequence, structure, and dynamics. © 2017 The Protein Society.

  2. Structural Evolution of Carbon During Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Adel F. Sarofim; Angelo Kandas

    1998-10-28

    The examination of the structural evolution of carbon during oxidation has proven to be of scientific interest. Early modeling work of fluidized bed combustion showed that most of the reactions of interest occurs iOn the micropores, and this work has concentrated on these pores. This work has concentrated on evolution of macroporosity and rnicroporosity of carbons during kinetic controlled oxidation using SAXS, C02 and TEM analysis. Simple studies of fluidized bed combustion of coal chars has shown that many of the events considered fragmentation events previously may in fact be "hidden" or nonaccessible porosity. This makes the study of the microporous combustion characteristics of carbon even more important. The generation of a combustion resistant grid, coupled with measurements of the SAXS and C02 surface areas, fractal analysis and TEM studies has confined that soot particles shrink during their oxidation, as previously suspected. However, this shrinkage results in an overall change in structure. This structure becomes, on a radial basis, much more ordered near the edges, while the center itself becomes transparent to the TEM beam, implying a total lack of structure in this region. Although complex, this carbon structure is probably burning as to keep the density of the soot particles nearly the same. The TEM techniques developed for examination of soots has also been applied to Spherocarb. The Spherocarb during oxidation also increases its ordering,. This ordering, by present theories, would imply that the reactivity would go. However, the reactivity goes up, implying that structure of carbon is secondary in importance to catalytic effects.

  3. Topology Optimization of Structure Using Differential Evolution

    Directory of Open Access Journals (Sweden)

    Chun-Yin Wu

    2008-02-01

    Full Text Available The population-based evolutionary algorithms have emerged as powerful mechanism for finding optimum solutions of complex optimization problems. A promising new evolutionary algorithm, differential evolution, has garnered significant attention in the engineering optimization research. Differential evolution has the advantage of incorporating a relatively simple and efficient form of mutation and crossover. This paper aims at introducing differential evolution as an alternative approach for topology optimization of truss and continuous structure with stress and displacement constraints. In comparison the results with other studies, it shows that differential evolution algorithms are very effective and efficient in solving topology optimization problem of structure.

  4. Photometric analysis of the structure evolution on the Pb-19.4%Sn melt surface in the S-L temperature range

    Directory of Open Access Journals (Sweden)

    Lyakhovitskii M.M.

    2011-05-01

    Full Text Available The structure evolution of alloys in solidification range is considered as the first-order phase transformation from the solid state to the liquid one, which occurs by the mechanism of nucleation and growth of more symmetrical phase to less symmetrical crystalline phase. The kinetic regularities of this transformation are studied by the method of the photometric analysis of structure images (PHASI, which makes it possible to establish the temperature dependence of the relationship between the solid and liquid phases and their distribution on the melt surface. The PHASI method is based on the combined analysis of the brightness spectra of the visible light reflections from the sample surface and of the distribution of its scattering centers in different intensity intervals. The data on the structure evolution of the Sn+19.4%Pb alloy upon melting and solidification were considered in parallel with the measured spectra of sound signals. It was revealed that a distinct maximum is observed in the temperature dependence of radiation energy in the temperature range of phase transformation from the liquid into the solid state and hot crack formation occurs near the transition zone in the region of the contact of the ingot with the crucible.

  5. Structural analysis of the bright monomeric yellow-green fluorescent protein mNeonGreen obtained by directed evolution.

    Science.gov (United States)

    Clavel, Damien; Gotthard, Guillaume; von Stetten, David; De Sanctis, Daniele; Pasquier, Hélène; Lambert, Gerard G; Shaner, Nathan C; Royant, Antoine

    2016-12-01

    Until recently, genes coding for homologues of the autofluorescent protein GFP had only been identified in marine organisms from the phyla Cnidaria and Arthropoda. New fluorescent-protein genes have now been found in the phylum Chordata, coding for particularly bright oligomeric fluorescent proteins such as the tetrameric yellow fluorescent protein lanYFP from Branchiostoma lanceolatum. A successful monomerization attempt led to the development of the bright yellow-green fluorescent protein mNeonGreen. The structures of lanYFP and mNeonGreen have been determined and compared in order to rationalize the directed evolution process leading from a bright, tetrameric to a still bright, monomeric fluorescent protein. An unusual discolouration of crystals of mNeonGreen was observed after X-ray data collection, which was investigated using a combination of X-ray crystallography and UV-visible absorption and Raman spectroscopies, revealing the effects of specific radiation damage in the chromophore cavity. It is shown that X-rays rapidly lead to the protonation of the phenolate O atom of the chromophore and to the loss of its planarity at the methylene bridge.

  6. Tectonic evolution of the eastern margin of the Thaumasia Plateau (Mars) as inferred from detailed structural mapping and analysis

    Science.gov (United States)

    Borraccini, F.; Di Achille, G.; Ori, G. G.; Wezel, F. C.

    2007-05-01

    The eastern margin of the Thaumasia Plateau (EMTP) is characterized by a diversity of tectonic features, which recorded its complex, and still controversial, tectonic history. A detailed structural survey and analyses have been carried out in order to assess the kinematics and relative age of the main deformational events. Combining results from statistics of lineament orientations and density of fault length for each geologic unit and taking into account crosscutting relationships among tectonic structures, three main deformational events have been recognized. The early stage of the tectonic evolution of EMTP is recorded by Noachian units at the southern edge of Melas Dorsa and is represented by N-S oriented grabens sutured by Early Hesperian formations. Starting from Late Noachian, the extensional stress field became NE-SW oriented and resulted in the formation of NW-SE striking sets of grabens. At the boundary between Noachian and Hesperian, the most important change in tectonic regime occurred. The Hesperian tectonics are characterized by an E-W shortening possibly related to an eastward motion of the Thaumasia Plateau. This tectonic phase likely produced a N-S-oriented wrinkle ridges as well as regional folds and thrust faults. E-W-oriented preexisting tectonic lineaments could have been reactivated forming regional transfer zones. In this scenario, Coprates Rise, Melas Dorsa, and Thaumasia Ridge could be interpreted as mountain belts resulting from buckling and thrust faulting of the eastern and southern margins of the Thaumasia plateau. The proto-Valles Marineris could have experienced a left-lateral component of displacement and played a role of a transfer shear zone.

  7. MADS-box gene evolution - structure and transcription patterns

    DEFF Research Database (Denmark)

    Johansen, Bo; Pedersen, Louise Buchholt; Skipper, Martin

    2002-01-01

    Mads-box genes, ABC model, Evolution, Phylogeny, Transcription patterns, Gene structure, Conserved motifs......Mads-box genes, ABC model, Evolution, Phylogeny, Transcription patterns, Gene structure, Conserved motifs...

  8. Stellar Structure and Evolution: An Introduction

    Science.gov (United States)

    Jeffery, C. Simon

    The synthesis of new elements takes place inside stars. How do stars evolve and distribute this creation to the universe at large? This article starts with the observables that the theory of stellar evolution aims to reproduce, and gives a quick overview of what that theory predicts (Sects. 2-3). It presents the equations governing stellar structure and evolution (Sects. 4-6) and the physics of stellar interiors (Sects. 7-9). Approximate and numerical methods for their solution are outlined (Sects. 10-11) and the general results of stellar structure and evolution are discussed (Sects. 12-13). The structure and evolution of horizontal-branch stars, hydrogen-deficient stars and other stellar remnants are also considered (Sects. 14-15).

  9. Ductile and brittle structural evolution of the Laxemar-Simpevarp area: an independent analysis based on local and regional constraints

    International Nuclear Information System (INIS)

    Viola, Giulio

    2008-10-01

    This report discusses the main aspects of the ductile and brittle deformational evolution of the Laxemar-Simpevarp area. Based on the interpretation of existing potential field geophysical data, it is suggested that the structural ductile grain of the region is controlled by large, c. EW trending shear zones with an overall sinistral strike-slip kinematics. The Oskarshamn Shear Zone (OSZ) and the Mederhult lineament are two examples of these shear zones and it is proposed that the ductile lineaments mapped in Laxemar-Simpevarp are genetically linked to shearing accommodated by these shear zones. The structural interpretation of the geophysical imagery of the Laxemar-Simpevarp regional model area and the available meso-scale structural information indicate that the Laxemar-Simpevarp study area can be interpreted as the analogue of a large-scale S/C' structural pattern. In detail, the Aespoe shear zone and other similarly oriented ductile shears represent C' shear bands that deform sinistrally the intervening EW lineaments (the S surfaces), which locally are significantly crenulated/folded in response to their asymptotic bending into the C' shears. This geometric and kinematic interpretation implies that, in contrast to existing reconstructions and models, EW- and not NE-trending shear zones become the main structural ductile feature of the region. Shear forces acting parallel to these main zones can successfully explain all the ductile structures described and reported from the area. The greatest compressive stress at the time of ductile shearing would trend NE-SW. The brittle deformation history of the region is complex and results from the multiple reactivation of fracture- and fault sets caused by the many orogenic episodes that affected the area during 1.5 Gyr of geological brittle evolution. Fault-slip data from outcrops and oriented drill cores were used to compute paleo-stress states. In the general absence of time markers that help constrain the relative

  10. Ductile and brittle structural evolution of the Laxemar-Simpevarp area: an independent analysis based on local and regional constraints

    Energy Technology Data Exchange (ETDEWEB)

    Viola, Giulio (Geological Survey of Norway, Trondheim (Norway))

    2008-10-15

    This report discusses the main aspects of the ductile and brittle deformational evolution of the Laxemar-Simpevarp area. Based on the interpretation of existing potential field geophysical data, it is suggested that the structural ductile grain of the region is controlled by large, c. EW trending shear zones with an overall sinistral strike-slip kinematics. The Oskarshamn Shear Zone (OSZ) and the Mederhult lineament are two examples of these shear zones and it is proposed that the ductile lineaments mapped in Laxemar-Simpevarp are genetically linked to shearing accommodated by these shear zones. The structural interpretation of the geophysical imagery of the Laxemar-Simpevarp regional model area and the available meso-scale structural information indicate that the Laxemar-Simpevarp study area can be interpreted as the analogue of a large-scale S/C' structural pattern. In detail, the Aespoe shear zone and other similarly oriented ductile shears represent C' shear bands that deform sinistrally the intervening EW lineaments (the S surfaces), which locally are significantly crenulated/folded in response to their asymptotic bending into the C' shears. This geometric and kinematic interpretation implies that, in contrast to existing reconstructions and models, EW- and not NE-trending shear zones become the main structural ductile feature of the region. Shear forces acting parallel to these main zones can successfully explain all the ductile structures described and reported from the area. The greatest compressive stress at the time of ductile shearing would trend NE-SW. The brittle deformation history of the region is complex and results from the multiple reactivation of fracture- and fault sets caused by the many orogenic episodes that affected the area during 1.5 Gyr of geological brittle evolution. Fault-slip data from outcrops and oriented drill cores were used to compute paleo-stress states. In the general absence of time markers that help constrain

  11. Large scale comparative codon-pair context analysis unveils general rules that fine-tune evolution of mRNA primary structure.

    Directory of Open Access Journals (Sweden)

    Gabriela Moura

    Full Text Available BACKGROUND: Codon usage and codon-pair context are important gene primary structure features that influence mRNA decoding fidelity. In order to identify general rules that shape codon-pair context and minimize mRNA decoding error, we have carried out a large scale comparative codon-pair context analysis of 119 fully sequenced genomes. METHODOLOGIES/PRINCIPAL FINDINGS: We have developed mathematical and software tools for large scale comparative codon-pair context analysis. These methodologies unveiled general and species specific codon-pair context rules that govern evolution of mRNAs in the 3 domains of life. We show that evolution of bacterial and archeal mRNA primary structure is mainly dependent on constraints imposed by the translational machinery, while in eukaryotes DNA methylation and tri-nucleotide repeats impose strong biases on codon-pair context. CONCLUSIONS: The data highlight fundamental differences between prokaryotic and eukaryotic mRNA decoding rules, which are partially independent of codon usage.

  12. Morphological analysis of Nevado de Toluca volcano (Mexico): new insights into the structure and evolution of an andesitic to dacitic stratovolcano

    Science.gov (United States)

    Norini, Gianluca; Groppelli, Gianluca; Capra, Lucia; De Beni, Emanuela

    2004-09-01

    We present a morphological analysis of Nevado de Toluca volcano located 80 km WSW of Mexico City based on digital elevation model study, where slope and aspect maps have been generated and analysed. Aerial photograph and satellite image observations improve the morphological analysis. The synoptic view which is offered by this analysis allowed for recognition and localization of the main volcanic and tectonic features of the area. On the basis of digital elevation model value distribution and surface textures, five morphological domains were defined. The most interesting domain, south of the crater, reflects the occurrence of an ancient complex volcano distinct from the adjacent areas. Interaction between the volcanic and volcano-tectonic evolution and the basement produced the other domains. Single volcanic edifices, like lava domes and scoria cones, and eruptive fractures were recognized. Finally, flank collapse scarps opened to the east and to the north were identified and four relevant morphostructural lineaments and their possible role in the Nevado de Toluca geological and structural evolution are discussed.

  13. Evolution of approaches to definition and structurization of intellectual capital

    OpenAIRE

    Virchenko, V.

    2012-01-01

    Article is devoted to analysis of peculiarities of evolution theoretical approaches to analysis of the nature of intellectual capital. The stages of development of the intellectual capital theory and approaches to it's structurization are investigated. Peculiarities of the intellectual capital are considered.

  14. Evolution of dinosaur epidermal structures.

    Science.gov (United States)

    Barrett, Paul M; Evans, David C; Campione, Nicolás E

    2015-06-01

    Spectacularly preserved non-avian dinosaurs with integumentary filaments/feathers have revolutionized dinosaur studies and fostered the suggestion that the dinosaur common ancestor possessed complex integumentary structures homologous to feathers. This hypothesis has major implications for interpreting dinosaur biology, but has not been tested rigorously. Using a comprehensive database of dinosaur skin traces, we apply maximum-likelihood methods to reconstruct the phylogenetic distribution of epidermal structures and interpret their evolutionary history. Most of these analyses find no compelling evidence for the appearance of protofeathers in the dinosaur common ancestor and scales are usually recovered as the plesiomorphic state, but results are sensitive to the outgroup condition in pterosaurs. Rare occurrences of ornithischian filamentous integument might represent independent acquisitions of novel epidermal structures that are not homologous with theropod feathers. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  15. Geodynamic evolution and mantle structure

    NARCIS (Netherlands)

    Jonge, M.R. de

    1995-01-01

    With the advent of plate tectonic theory a framework has become available in which many observed features of the structure of the Earth can be understood. The theory can explain the geological processes that have resulted in terranes as diverse as oceans, mid-oceanic ridges, mountain belts, and

  16. Evolution of Coextruded Structures in Static Mixers

    Science.gov (United States)

    Sollogoub, C.; Guinault, A.; Pedros, M.

    2007-04-01

    Coextrusion allows to combine two thermoplastics in different ways, creating structures with different cross-sectional geometries (side-by-side structure or concentric ring structure). We use static mixers after the feedblock, in order to homogenise these initial structures and obtain different blend morphologies. The control of these morphologies is of prime importance in order to predict the final properties of the polymer blends. The aim of this paper is to study the evolution of some initial coextruded structures in different static mixers. Different static mixers, with adjustable number of mixing elements, are tested. The experimental observations are confronted with numerical simulation results.

  17. Evolution of Structural DNA Nanotechnology.

    Science.gov (United States)

    Nummelin, Sami; Kommeri, Juhana; Kostiainen, Mauri A; Linko, Veikko

    2018-01-24

    The research field entitled structural DNA nanotechnology emerged in the beginning of the 1980s as the first immobile synthetic nucleic acid junctions were postulated and demonstrated. Since then, the field has taken huge leaps toward advanced applications, especially during the past decade. This Progress Report summarizes how the controllable, custom, and accurate nanostructures have recently evolved together with powerful design and simulation software. Simultaneously they have provided a significant expansion of the shape space of the nanostructures. Today, researchers can select the most suitable fabrication methods, and design paradigms and software from a variety of options when creating unique DNA nanoobjects and shapes for a plethora of implementations in materials science, optics, plasmonics, molecular patterning, and nanomedicine. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Cross-linked structure of network evolution

    International Nuclear Information System (INIS)

    Bassett, Danielle S.; Wymbs, Nicholas F.; Grafton, Scott T.; Porter, Mason A.; Mucha, Peter J.

    2014-01-01

    We study the temporal co-variation of network co-evolution via the cross-link structure of networks, for which we take advantage of the formalism of hypergraphs to map cross-link structures back to network nodes. We investigate two sets of temporal network data in detail. In a network of coupled nonlinear oscillators, hyperedges that consist of network edges with temporally co-varying weights uncover the driving co-evolution patterns of edge weight dynamics both within and between oscillator communities. In the human brain, networks that represent temporal changes in brain activity during learning exhibit early co-evolution that then settles down with practice. Subsequent decreases in hyperedge size are consistent with emergence of an autonomous subgraph whose dynamics no longer depends on other parts of the network. Our results on real and synthetic networks give a poignant demonstration of the ability of cross-link structure to uncover unexpected co-evolution attributes in both real and synthetic dynamical systems. This, in turn, illustrates the utility of analyzing cross-links for investigating the structure of temporal networks

  19. Cross-linked structure of network evolution

    Energy Technology Data Exchange (ETDEWEB)

    Bassett, Danielle S., E-mail: dsb@seas.upenn.edu [Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Department of Physics, University of California, Santa Barbara, California 93106 (United States); Sage Center for the Study of the Mind, University of California, Santa Barbara, California 93106 (United States); Wymbs, Nicholas F.; Grafton, Scott T. [Department of Psychology and UCSB Brain Imaging Center, University of California, Santa Barbara, California 93106 (United States); Porter, Mason A. [Oxford Centre for Industrial and Applied Mathematics, Mathematical Institute, University of Oxford, Oxford OX2 6GG (United Kingdom); CABDyN Complexity Centre, University of Oxford, Oxford, OX1 1HP (United Kingdom); Mucha, Peter J. [Carolina Center for Interdisciplinary Applied Mathematics, Department of Mathematics, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Department of Applied Physical Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 (United States)

    2014-03-15

    We study the temporal co-variation of network co-evolution via the cross-link structure of networks, for which we take advantage of the formalism of hypergraphs to map cross-link structures back to network nodes. We investigate two sets of temporal network data in detail. In a network of coupled nonlinear oscillators, hyperedges that consist of network edges with temporally co-varying weights uncover the driving co-evolution patterns of edge weight dynamics both within and between oscillator communities. In the human brain, networks that represent temporal changes in brain activity during learning exhibit early co-evolution that then settles down with practice. Subsequent decreases in hyperedge size are consistent with emergence of an autonomous subgraph whose dynamics no longer depends on other parts of the network. Our results on real and synthetic networks give a poignant demonstration of the ability of cross-link structure to uncover unexpected co-evolution attributes in both real and synthetic dynamical systems. This, in turn, illustrates the utility of analyzing cross-links for investigating the structure of temporal networks.

  20. Structure and evolution of the Moon

    International Nuclear Information System (INIS)

    Taylor, S.R.

    1979-01-01

    The scientific investigation of the samples returned by the Apollo and Luna missions, together with geophysical and photogeological data, has provided a reasonably complete understanding of the structure, composition and evolution of the Moon, and has placed many constraints on theories of its origin. Data obtained from these investigations are reviewed. 87 references. (author)

  1. Evolution of the Chos Malal and Agrio fold and thrust belts, Andes of Neuquén: Insights from structural analysis and apatite fission track dating

    Science.gov (United States)

    Rojas Vera, E. A.; Mescua, J.; Folguera, A.; Becker, T. P.; Sagripanti, L.; Fennell, L.; Orts, D.; Ramos, V. A.

    2015-12-01

    The Chos Malal and Agrio fold and thrust belts are located in the western part of the Neuquén basin, an Andean retroarc basin of central-western Argentina. Both belts show evidence of tectonic inversion at the western part during Late Cretaceous times. The eastern part is dominated by late Miocene deformation which also partially reactivated the western structures. This work focuses on the study of the regional structure and the deformational event that shaped the relief of this part of the Andes. Based on new field work and structural data and previously published works a detailed map of the central part of the Neuquén basin is presented. Three regional structural cross sections were surveyed and balanced using the 2d Move™ software. In order to define a more accurate uplift history, new apatite fission track analyses were carried on selected structures. These data was used for new thermal history modeling of the inner part of the Agrio and Chos Malal fold and thrust belts. The results of the fission track analyses improve the knowledge of how these fold and thrust belts have grown trough time. Two main deformational events are defined in Late Cretaceous to Paleocene and Late Miocene times. Based on this regional structural analysis and the fission track data the precise location of the orogenic front for the Late Cretaceous-Paleocene times is reconstructed and it is proposed a structural evolution of this segment of the Andes. This new exhumation data show how the Late Cretaceous to Paleocene event was a continuous and uninterrupted deformational event.

  2. A Teaching Module about Stellar Structure and Evolution

    Science.gov (United States)

    Colantonio, Arturo; Galano, Silvia; Leccia, Silvio; Puddu, Emanuella; Testa, Italo

    2017-01-01

    In this paper, we present a teaching module about stellar structure, functioning and evolution. Drawing from literature in astronomy education, we designed the activities around three key ideas: spectral analysis, mechanical and thermal equilibrium, energy and nuclear reactions. The module is divided into four phases, in which the key ideas for…

  3. INVESTMENT STRUCTURE AND EVOLUTION IN THE CONTEXT OF ECONOMIC CRISIS

    Directory of Open Access Journals (Sweden)

    CODAU CIPRIAN-CRACIUN

    2011-12-01

    Full Text Available The scope of this article is the evolution analysis of net investment in Romania between economic growth and international economic crisis. The analysis captures both the evolution of net investment by structure elements (buildings, outfits, other investments and the structure and evolution of investments by sources of financing. Also there is an analysis of the foreign direct investment (FDI share in the total net investment and the impact of the economic crisis on this share. The article aims to identify the main factors for the evolution of investments in Romania before the financial crisis and determine how the financial crisis influenced the structure and volume of investments in the national economy. Most previous studies have focused either on a small part of the investments made in Romania (in most cases the FDI have been analyzed or on the period of economic expansion without capturing the evolution of investment during the economic crisis. Previous research has highlighted especially the FDI influence on macroeconomic indicators of high importance for the economy (unemployment rate, GDP growth rate, etc. with less focus on the factors influencing these investments and the close connection between the economic context (economy status and the volume of these investments. For the analysis of the investment evolution during the mentioned period statistical data was used that captured both the investment evolution trend and the changes occurred by the national economy stepping into recession amid the global financial crisis established. To get an overview of the situation it was considered a time internal that captured both the economic growth and the period after the onset of the economic crisis. Thereby information was obtained on the volume of net investment during 2000-2010, on foreign direct investment in the period 2003-2010 and their share in total net investment and also on the main sources of investment financing during the

  4. Crystallography, evolution, and the structure of viruses.

    Science.gov (United States)

    Rossmann, Michael G

    2012-03-16

    My undergraduate education in mathematics and physics was a good grounding for graduate studies in crystallographic studies of small organic molecules. As a postdoctoral fellow in Minnesota, I learned how to program an early electronic computer for crystallographic calculations. I then joined Max Perutz, excited to use my skills in the determination of the first protein structures. The results were even more fascinating than the development of techniques and provided inspiration for starting my own laboratory at Purdue University. My first studies on dehydrogenases established the conservation of nucleotide-binding structures. Having thus established myself as an independent scientist, I could start on my most cherished ambition of studying the structure of viruses. About a decade later, my laboratory had produced the structure of a small RNA plant virus and then, in another six years, the first structure of a human common cold virus. Many more virus structures followed, but soon it became essential to supplement crystallography with electron microscopy to investigate viral assembly, viral infection of cells, and neutralization of viruses by antibodies. A major guide in all these studies was the discovery of evolution at the molecular level. The conservation of three-dimensional structure has been a recurring theme, from my experiences with Max Perutz in the study of hemoglobin to the recognition of the conserved nucleotide-binding fold and to the recognition of the jelly roll fold in the capsid protein of a large variety of viruses.

  5. Protein structure and neutral theory of evolution.

    Science.gov (United States)

    Ptitsyn, O B; Volkenstein, M V

    1986-08-01

    The neutral theory of evolution is extended to the origin of protein molecules. Arguments are presented which suggest that the amino acid sequences of many globular proteins mainly represent "memorized" random sequences while biological evolution reduces to the "editing" these random sequences. Physical requirements for a functional globular protein are formulated and it is shown that many of these requirement do not involve strategical selection of amino acid sequences during biological evolution but are inherent also for typical random sequences. In particular, it is shown that random sequences of polar and amino acid residues can form alpha-helices and beta-strand with lengths and arrangement along the chain similar to those in real globular proteins. These alpha- and beta-regions in random sequences can form three-dimensional folding patterns also similar to those in proteins. The arguments are presented suggesting that even the tight packing of side groups inside protein core do not require very strong biological selection of amino acid sequences either. Thus many structural features of real proteins can exist also in random sequences and the biological selection is needed mainly for the creation of active site of protein and for their stability under physiological conditions.

  6. The structure and evolution of the Sun

    CERN Document Server

    Severino, Giuseppe

    2017-01-01

    This book equips the reader with a coherent understanding of the structure of the Sun and its evolution and provides all the knowledge required to construct a simplified model of the Sun. The early chapters cover key aspects of basic physics and describe the Sun’s size, mass, luminosity, and temperature. Using a semi-empirical approach, the structure of the present Sun is then modeled in detail, layer by layer, proceeding from the photosphere to the convection zone, radiation zone, and core. Finally, all stages of the Sun’s evolution, from its formation to the end of its life, are carefully explained. The book is primarily intended for university students taking the initial steps in moving from physics to astrophysics. It includes worked exercises and problems to illustrate the concepts discussed, as well as additional problems for independent study. With the aim of helping the reader as much as possible, most of the mathematics required to use the book are provided in the text.

  7. Structural Analysis of Histo-Blood Group Antigen Binding Specificity in a Norovirus GII.4 Epidemic Variant: Implications for Epochal Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Shanker, Sreejesh; Choi, Jae-Mun; Sankaran, Banumathi; Atmar, Robert L.; Estes, Mary K.; Prasad, B.V. Venkataram (Baylor); (LBNL)

    2012-03-23

    Susceptibility to norovirus (NoV), a major pathogen of epidemic gastroenteritis, is associated with histo-blood group antigens (HBGAs), which are also cell attachment factors for this virus. GII.4 NoV strains are predominantly associated with worldwide NoV epidemics with a periodic emergence of new variants. The sequence variations in the surface-exposed P domain of the capsid protein resulting in differential HBGA binding patterns and antigenicity are suggested to drive GII.4 epochal evolution. To understand how temporal sequence variations affect the P domain structure and contribute to epochal evolution, we determined the P domain structure of a 2004 variant with ABH and secretor Lewis HBGAs and compared it with the previously determined structure of a 1996 variant. We show that temporal sequence variations do not affect the binding of monofucosyl ABH HBGAs but that they can modulate the binding strength of difucosyl Lewis HBGAs and thus could contribute to epochal evolution by the potentiated targeting of new variants to Lewis-positive, secretor-positive individuals. The temporal variations also result in significant differences in the electrostatic landscapes, likely reflecting antigenic variations. The proximity of some of these changes to the HBGA binding sites suggests the possibility of a coordinated interplay between antigenicity and HBGA binding in epochal evolution. From the observation that the regions involved in the formation of the HBGA binding sites can be conformationally flexible, we suggest a plausible mechanism for how norovirus disassociates from salivary mucin-linked HBGA before reassociating with HBGAs linked to intestinal epithelial cells during its passage through the gastrointestinal tract.

  8. Evolution of groups with a hierarchical structure

    Science.gov (United States)

    Ohnishi, Teruaki

    2012-12-01

    The universal occurrence of a hierarchical structure and its dynamic behavior in various types of group, living or abstract, are discussed. Here the word “group” refers not only to tangible aggregation but also to invisible aggregation of social psychological and of geopolitical meaning. The evolution of these groups is simulated using a model of agents distributed on the lattices of cellular grids. It is assumed that agents, fearing isolation, interact asymmetrically with each other with regard to exchange of “power”. As an indicator of hierarchy, the Gini coefficient is introduced. Example calculations are made for the aggregation, fusion and fission of animal groups, and for the appearance of a powerful empire and the rise and fall of supremacy. It is shown that such abstract objects evolve with time in accordance with the universal rules of groups common to birds and fish.

  9. Structural evolution in the crystallization of rapid cooling silver melt

    Science.gov (United States)

    Tian, Z. A.; Dong, K. J.; Yu, A. B.

    2015-03-01

    The structural evolution in a rapid cooling process of silver melt has been investigated at different scales by adopting several analysis methods. The results testify Ostwald's rule of stages and Frank conjecture upon icosahedron with many specific details. In particular, the cluster-scale analysis by a recent developed method called LSCA (the Largest Standard Cluster Analysis) clarified the complex structural evolution occurred in crystallization: different kinds of local clusters (such as ico-like (ico is the abbreviation of icosahedron), ico-bcc like (bcc, body-centred cubic), bcc, bcc-like structures) in turn have their maximal numbers as temperature decreases. And in a rather wide temperature range the icosahedral short-range order (ISRO) demonstrates a saturated stage (where the amount of ico-like structures keeps stable) that breeds metastable bcc clusters. As the precursor of crystallization, after reaching the maximal number bcc clusters finally decrease, resulting in the final solid being a mixture mainly composed of fcc/hcp (face-centred cubic and hexagonal-closed packed) clusters and to a less degree, bcc clusters. This detailed geometric picture for crystallization of liquid metal is believed to be useful to improve the fundamental understanding of liquid-solid phase transition.

  10. Mathematical Analysis of Evolution, Information, and Complexity

    CERN Document Server

    Arendt, Wolfgang

    2009-01-01

    Mathematical Analysis of Evolution, Information, and Complexity deals with the analysis of evolution, information and complexity. The time evolution of systems or processes is a central question in science, this text covers a broad range of problems including diffusion processes, neuronal networks, quantum theory and cosmology. Bringing together a wide collection of research in mathematics, information theory, physics and other scientific and technical areas, this new title offers elementary and thus easily accessible introductions to the various fields of research addressed in the book.

  11. Topological structure of the solution set for evolution inclusions

    CERN Document Server

    Zhou, Yong; Peng, Li

    2017-01-01

    This book systematically presents the topological structure of solution sets and attractability for nonlinear evolution inclusions, together with its relevant applications in control problems and partial differential equations. It provides readers the background material needed to delve deeper into the subject and explore the rich research literature.  In addition, the book addresses many of the basic techniques and results recently developed in connection with this theory, including the structure of solution sets for evolution inclusions with m-dissipative operators; quasi-autonomous and non-autonomous evolution inclusions and control systems;evolution inclusions with the Hille-Yosida operator; functional evolution inclusions; impulsive evolution inclusions; and stochastic evolution inclusions. Several applications of evolution inclusions and control systems are also discussed in detail.  Based on extensive research work conducted by the authors and other experts over the past four years, the information p...

  12. Fabric Analysis in the Koppal Granitoid (Southern India) using AMS and its significance in understanding the structural evolution of Dharwar Craton

    Science.gov (United States)

    Bhatt, Sandeep; Mamtani, Manish A.; Rana, Virendra

    2016-04-01

    fabric recorded in the gneisses is having an orientation varying from NW-NNW. In some parts of the Koppal Granitoid, a foliation with NE-NNE orientation is recorded; however several parts of this granitoid do not show a clear foliation. Therefore, to analyse the fabric in the granitoid, the authors have carried out AMS analysis, and it is found that the mean orientation of the magnetic foliation is NNE (20° /64° /110°). These initial results indicate that whilst the host rock (gneiss) has NW-SE fabric, the Koppal granitoid is dominated by NE-SW planar fabric. This indicates that the granitoid fabric developed during regional D3 deformation that was on account of NW-SE compression, which is in contrast to the granitoids of WDC (Mulgund Granitoid). It is envisaged that further integration of microstructural studies with the above information will enhance the existing knowledge of the accretionary processes and kinematic evolution of Dharwar craton. References Chadwick et al., 2003 B. Chadwick, V.N. Vasudev, G.V. Hedge The Chitradurga schist belt and its adjacent plutonic rocks NW of Tungabhadra: Karnataka: a duplex in the late Archean convergent setting of the Dharwar craton Journal of the Geological Society of India, v.61, pp. 611-613. Mondal, T.K., Mamtani, M.A. (2013). 3-D Mohr circle construction using vein orientation data from Gadag (southern India) Implications to recognize fluid pressure fluctuation. Journal of Structural Geology, v. 56, pp.45-56. Mondal, T.K. and Mamtani, M.A., 2014. Fabric analysis in rocks of the Gadag region (southern India) - Implications for time relationship between regional deformation and gold mineralization. Tectonophysics, v. 629, pp.238-249. Mondal, T.K. and Mamtani, M.A., 2016. Palaeostress analysis of normal faults in granite-implications for interpreting Riedel shearing related to regional deformation. Journal of the Geological Society, v.173 (1), pp.216-227.

  13. Structural evolution in the crystallization of rapid cooling silver melt

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Z.A., E-mail: ze.tian@gmail.com [School of Physics and Electronics, Hunan University, Changsha 410082 (China); Laboratory for Simulation and Modelling of Particulate Systems School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Dong, K.J.; Yu, A.B. [Laboratory for Simulation and Modelling of Particulate Systems School of Materials Science and Engineering, University of New South Wales, Sydney, NSW 2052 (Australia)

    2015-03-15

    The structural evolution in a rapid cooling process of silver melt has been investigated at different scales by adopting several analysis methods. The results testify Ostwald’s rule of stages and Frank conjecture upon icosahedron with many specific details. In particular, the cluster-scale analysis by a recent developed method called LSCA (the Largest Standard Cluster Analysis) clarified the complex structural evolution occurred in crystallization: different kinds of local clusters (such as ico-like (ico is the abbreviation of icosahedron), ico-bcc like (bcc, body-centred cubic), bcc, bcc-like structures) in turn have their maximal numbers as temperature decreases. And in a rather wide temperature range the icosahedral short-range order (ISRO) demonstrates a saturated stage (where the amount of ico-like structures keeps stable) that breeds metastable bcc clusters. As the precursor of crystallization, after reaching the maximal number bcc clusters finally decrease, resulting in the final solid being a mixture mainly composed of fcc/hcp (face-centred cubic and hexagonal-closed packed) clusters and to a less degree, bcc clusters. This detailed geometric picture for crystallization of liquid metal is believed to be useful to improve the fundamental understanding of liquid–solid phase transition. - Highlights: • A comprehensive structural analysis is conducted focusing on crystallization. • The involved atoms in our analysis are more than 90% for all samples concerned. • A series of distinct intermediate states are found in crystallization of silver melt. • A novelty icosahedron-saturated state breeds the metastable bcc state.

  14. Molluscan hemocyanin: structure, evolution, and physiology.

    Science.gov (United States)

    Kato, Sanae; Matsui, Takashi; Gatsogiannis, Christos; Tanaka, Yoshikazu

    2017-12-12

    Most molluscs have blue blood because their respiratory molecule is hemocyanin, a type-3 copper-binding protein that turns blue upon oxygen binding. Molluscan hemocyanins are huge cylindrical multimeric glycoproteins that are found freely dissolved in the hemolymph. With molecular masses ranging from 3.3 to 13.5 MDa, molluscan hemocyanins are among the largest known proteins. They form decamers or multi-decamers of 330- to 550-kDa subunits comprising more than seven paralogous functional units. Based on the organization of functional domains, they assemble to form decamers, di-decamers, and tri-decamers. Their structure has been investigated using a combination of single particle electron cryo-microsopy of the entire structure and high-resolution X-ray crystallography of the functional unit, although, the one exception is squid hemocyanin for which a crystal structure analysis of the entire molecule has been carried out. In this review, we explain the molecular characteristics of molluscan hemocyanin mainly from the structural viewpoint, in which the structure of the functional unit, architecture of the huge cylindrical multimer, relationship between the composition of the functional unit and entire tertiary structure, and possible functions of the carbohydrates are introduced. We also discuss the evolutionary implications and physiological significance of molluscan hemocyanin.

  15. The early-stage structural evolution of the Barmer Basin rift, Rajasthan, northwest India

    OpenAIRE

    Bladon, Andrew John

    2015-01-01

    The structural evolution of the Barmer Basin and the context of the rift within the northwest Indian region are poorly understood, despite being a prolific hydrocarbon province. In this work an integrated basin analysis is presented covering the outcrop-, seismic-, and lithosphere-scales. The early-stage structural evolution and the origin of poorly understood structural complications in the Barmer Basin subsurface are assessed. Subsequently, the findings are placed within the wider context o...

  16. Structural evolution of carbon during oxidation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sarofim, A.F.

    1998-04-01

    The examination of the structural evolution of carbon during oxidation has proven to be of scientific interest. Early modeling work of fluidized bed combustion showed that most of the reactions of interest occurs in the micropores, and this work has concentrated on these pores. This work has concentrated on evolution of macroporosity and microporosity of carbons during kinetic controlled oxidation using SAXS, CO{sub 2} and TEM analysis. Simple studies of fluidized bed combustion of coal chars has shown that many of the events considered fragmentation events previously may in fact be {open_quotes}hidden{close_quotes} or nonaccessible porosity. This makes the study of the microporous combustion characteristics of carbon even more important. The generation of a combustion resistant grid, coupled with measurements of the SAXS and CO{sub 2} surface areas, fractal analysis and TEM. Studies has confirmed that soot particles shrink during their oxidation, as previously suspected. However, this shrinkage results in an overall change in structure. This structure becomes, on a radial basis, much more ordered near the edges, while the center itself becomes transparent to the TEM beam, implying a total lack of structure in this region. Although complex, this carbon structure is probably burning as to keep the density of the soot particles nearly the same. The TEM techniques developed for examination of soots has also been applied to Spherocarb. The Spherocarb during oxidation also increases its ordering. This ordering, by present theories, would imply that the reactivity would go. However, the reactivity goes up, implying that structure of carbon is secondary in importance to catalytic effects.

  17. Analysis of the geological structure and tectonic evolution of Xingning-Jinghai sag in deep water area, northern South China Sea

    Science.gov (United States)

    Han, Xiaoying; Ren, Jianye; Lin, Zi; Yang, Linlong

    2015-04-01

    Recent years, oil and gas exploration of the Pearl River Mouth Basin in the northern margin of South China Sea continuously achieved historic breakthroughs. The Xingning-Jinghai sag, which is located in southeast of the Pearl River Mouth Basin, is a deep-water sag with a great exploration potential. Its tectonic evolution is extremely complex. It experienced Mesozoic subduction to Cenozoic intra-continental rifting background, and finally evolved into a deep-water sag of the northern continental margin of South China Sea. The geological characteristics and the tectonic evolution of Xingning-Jinghai sag was closely related to the process of formation and evolution of the passive continental margin of the northern South China Sea. It is confirmed by many geophysical data that compared with adjacent Chaoshan depression, the crustal thickness of Xingning-Jinghai sag was rapidly thinning, and it developed detachment faults with later magmatic intrusion. The development of detachment faults have dynamic significance for the spreading of the South China Sea. Based on the seismic geological interpretation of 2D seismic data in the study area, the characteristics of detachment fault and supra-detachment basin have been proposed in this study. The characteristics of the detachment fault are low angle and high ratio between heave and throw. The geometry of the detachment fault is a typical lisric shape, with the dip of fault decreasing generally from the seismic profile. The detachment basin where sediments are not deposited over a tilting hanging-wall block but onto a tectonically exhumed footwall which is different from the typical half graben basin. Seismic profiles indicate two different structural styles in the east and west part of Xingning-Jinghai sag. In the west of the sag, there developed two large detachment faults, which control their detachment basin systems and the typical H block, and the two detachment faults are dipping landward and seaward, respectively. In

  18. Structure and evolution of Jupiter: the fluid contraction stage

    International Nuclear Information System (INIS)

    Graboske, H.C. Jr.; Pollack, J.B.; Grossman, A.S.; Olness, R.J.

    1975-01-01

    An evolutionary study of a 0.00095 M/sub sun/ star, composed of a convective, adiabatic, homogeneous fluid, has been performed using stellar structure methods. A new numerical technique is used to calculate model atmospheres in the form of time-average vertical temperatures structures, including all relevant opacity sources and a solar energy deposition component. Thermodynamic properties for pure hydrogen and a solar mixture (X=0.74, Y=0.24, Z=0.02) are developed for -7less than or equal tolog rho (g cm -3 ) less than or equal to1 and 1.78less than or equal tolog T (K) less than or equal to4.78, utilizing recent high-pressure experimental results and new theoretical methods. The resultant gravitationally contracting evolutionary models exhibit two phases. An early stellar phase, behaving like a typical low-mass pre-main-sequence object, has high luminosities which have left a record in the structure of the Galilean satellites. This phase also has high internal temperature, (T/subc/)) reaching 51,400, which ensures a long subsequent evolution as a fully mixed, convective structure. The second phase is an approach to a degenerate dwarf cooling curve, which gives excellent agreement with the observed radius and luminosity of Jupiter. A short time scale for the standard adiabatic fluid models (2.6times10 9 ) is extended by combinations of several factors influencing the planetar []evolution. An analysis of the sensitivity of evolution to chemical composition, solar energy deposition, equation of state, model atmospheres, and superadiabaticity demonstrates that the equation of state and superadiabaticity have the strongest influence over planetary time scales. (auth)

  19. Evolution of groundwater chemistry along fault structures in sandstone

    Science.gov (United States)

    Dausse, A.; Guiheneuf, N.; Pierce, A. A.; Cherry, J. A.; Parker, B. L.

    2016-12-01

    Fluid-rock interaction across geological structures plays a major role on evolution of groundwater chemistry and physical properties of reservoirs. In particular, groundwater chemistry evolve on different facies according to residence times which can be linked to hydraulic properties of the geological unit. In this study, we analyze groundwater samples collected at an 11 km² site located in southern California (USA) to evaluate the evolution of groundwater chemistry according to different geological structures. Major and minor elements were sampled at the same period of time from 40 wells located along the main structures in the northeast of the site, where major NE-SW trending faults and other oriented ESE-WNW are present in sandstone Chatsworth formation. By analyzing the spatial distribution of ions concentration at the site scale, several hydrochemical compartments (main- and sub-compartments) can be distinguished and are in agreement with structural and hydrological information. In particular, as previously observed from piezometric informations, the shear zone fault serves as a barrier for groundwater flow and separates the site on two mains compartments. In addition, the analysis along major faults oriented orthogonal to this shear zone (ESE-WNW) in the eastern part of the site, shows an increase in mineralization following the hydraulic gradient. This salinization has been confirmed by ionic ratio and Gibbs plots and is attributed to fluid-rock interaction processes. In particular, groundwater chemistry seems to evolve from bicarbonate to sodium facies. Moreover, the gradient of concentrations vary depending on fault locations and can be related to their hydraulic properties and hence to different characteristic times from point to point. To conclude, major faults across the site display different degrees of groundwater chemistry evolution, linked to their physical properties, which may in turn have a large impact on contaminant transport and attenuation.

  20. Effects of Rock Type and Geologic Process on the Structure and Evolution of Nano, Meso and Micro-Scale Porosity: A (U)SANS, SEM/BSE Analysis

    Science.gov (United States)

    Anovitz, L.; Wang, H.; Cole, D. R.; Rother, G.

    2012-12-01

    The microstructure and evolution of porosity in time and space play a critical role in many geologic processes, including the migration and retention of water, gas and hydrocarbons, the evolution of hydrothermal systems, weathering, diagenesis and metamorphism, as well as technological processes such as CO2 sequestration, shale gas and secondary oil recovery. The size, distribution and connectivity of these confined geometries collectively dictate how fluids migrate into and through these micro- and nanoenvironments, wet and react with mineral surfaces. (Ultra)small-angle neutron scattering and autocorrelations derived from SEM/BSE imaging provide a method of quantifying pore structures in a statistically significant manner from the nanometer to the centimeter scale. Data from this approach suggests that there are significant primary and evolutionary differences between the multiscale pore structures of carbonate and clastic rocks. Our work on the St. Peter sandstone shows total porosity correlates with changes in pores structure including pore size ratios, surface fractal dimensions, and lacunarity. There is no evidence of mass-fractal scattering and while previous scattering data from sandstones suggest scattering is dominated by surface fractal behavior over many orders of magnitude, our data show both fractal and pseudo-fractals. Larger pores fill at a faster rate than small pores as overgrowths form, leading to an increase in the small/large pore ratio. Overall, therefore, the relative importance of fluid reactions in confined geometries is likely to increase with increased silcrete formation. The changes observed with overgrowth formation in sandstones contrast with available data for metamorphism of chemical sediments (limestones) in both the Marble Canyon contact aureole, TX (Anovitz et al., 2009), and the Hatrurim Fm. (the Mottled Zone), Israel. The unmetamorphosed limestones both show distinct multifractal scattering patterns at larger scales, and true

  1. Triadic conceptual structure of the maximum entropy approach to evolution.

    Science.gov (United States)

    Herrmann-Pillath, Carsten; Salthe, Stanley N

    2011-03-01

    Many problems in evolutionary theory are cast in dyadic terms, such as the polar oppositions of organism and environment. We argue that a triadic conceptual structure offers an alternative perspective under which the information generating role of evolution as a physical process can be analyzed, and propose a new diagrammatic approach. Peirce's natural philosophy was deeply influenced by his reception of both Darwin's theory and thermodynamics. Thus, we elaborate on a new synthesis which puts together his theory of signs and modern Maximum Entropy approaches to evolution in a process discourse. Following recent contributions to the naturalization of Peircean semiosis, pointing towards 'physiosemiosis' or 'pansemiosis', we show that triadic structures involve the conjunction of three different kinds of causality, efficient, formal and final. In this, we accommodate the state-centered thermodynamic framework to a process approach. We apply this on Ulanowicz's analysis of autocatalytic cycles as primordial patterns of life. This paves the way for a semiotic view of thermodynamics which is built on the idea that Peircean interpretants are systems of physical inference devices evolving under natural selection. In this view, the principles of Maximum Entropy, Maximum Power, and Maximum Entropy Production work together to drive the emergence of information carrying structures, which at the same time maximize information capacity as well as the gradients of energy flows, such that ultimately, contrary to Schrödinger's seminal contribution, the evolutionary process is seen to be a physical expression of the Second Law. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  2. The Pendulum Strikes Back? An Analysis of the Evolution of Hungarian Higher Education Governance and Organisational Structures since the 1980s

    Science.gov (United States)

    Kováts, Gergely; Heidrich, Balázs; Chandler, Nick

    2017-01-01

    Higher education in Central Europe has been scrutinised from many different perspectives during the last 30 years. In our analysis, we focus solely on Hungary and specifically on two key areas: governance and organisational structure. Using an analytical model proposed by Leisyte (2014), we analyse how the governance and organisational structure…

  3. Predicting the structural evolution of networks by applying multivariate time series

    Science.gov (United States)

    Huang, Qiangjuan; Zhao, Chengli; Wang, Xiaojie; Zhang, Xue; Yi, Dongyun

    2015-06-01

    In practice, complex systems often change over time, and the temporal characteristics of a complex network make their behavior difficult to predict. Traditional link prediction methods based on structural similarity are good for mining underlying information from static networks, but do not always capture the temporal relevance of dynamic networks. However, time series analysis is an effective tool for examining dynamic evolution. In this paper, we combine link prediction with multivariate time series analysis to describe the structural evolution of dynamic networks using both temporal information and structure information. An empirical analysis demonstrates the effectiveness of our method in predicting undiscovered linkages in two classic networks.

  4. Evolution and development of mammalian limb integumentary structures.

    Science.gov (United States)

    Hamrick, Mark W

    2003-08-15

    The adaptive radiation of mammalian clades has involved marked changes in limb morphology that have affected not only the skeleton but also the integumentary structures. For example, didelphid marsupials show distinct differences in nail and claw morphology that are functionally related to the evolution of arboreal, terrestrial, and aquatic foraging behaviors. Vespertilionoid bats have evolved different volar pad structures such as adhesive discs, scales, and skin folds, whereas didelphid marsupials have apical pads covered either with scales, ridges, or small cones. Comparative analysis of pad and claw development reveals subtle differences in mesenchymal and ectodermal patterning underlying interspecific variation in morphology. Analysis of gene expression during pad and claw development reveals that signaling molecules such as Msx1 and Hoxc13 play important roles in the morphogenesis of these integumentary structures. These findings suggest that evolutionary change in the expression of these molecules, and in the response of mesenchymal and ectodermal cells to these signaling factors, may underlie interspecific differences in nail, claw, and volar pad morphology. Evidence from comparative morphology, development, and functional genomics therefore sheds new light on both the patterns and mechanisms of evolutionary change in mammalian limb integumentary structures. Copyright 2003 Wiley-Liss, Inc.

  5. Evolution and Structural Analyses of Glossina morsitans (Diptera; Glossinidae) Tetraspanins

    NARCIS (Netherlands)

    Murungi, E.K.; Kariithi, H.M.; Adunga, V.; Obonyo, M.; Christoffels, A.

    2014-01-01

    Tetraspanins are important conserved integral membrane proteins expressed in many organisms. Although there is limited knowledge about the full repertoire, evolution and structural characteristics of individual members in various organisms, data obtained so far show that tetraspanins play major

  6. The Evolution of Sulfide in Shallow Aquatic Ecosystem Sediments: An Analysis of the Roles of Sulfate, Organic Carbon, and Iron and Feedback Constraints Using Structural Equation Modeling

    Science.gov (United States)

    Pollman, C. D.; Swain, E. B.; Bael, D.; Myrbo, A.; Monson, P.; Shore, M. D.

    2017-11-01

    The generation of elevated concentrations of sulfide in sediment pore waters that are toxic to rooted macrophytes is problematic in both marine and freshwaters. In marine waters, biogeochemical conditions that lead to toxic levels of sulfide generally relate to factors that affect oxygen dynamics or the sediment iron concentration. In freshwaters, increases in surface water sulfate have been implicated in decline of Zizania palustris (wild rice), which is important in wetlands across the Great Lakes region of North America. We developed a structural equation (SE) model to elucidate key variables that govern the evolution of sulfide in pore waters in shallow aquatic habitats that are potentially capable of supporting wild rice. The conceptual basis for the model is the hypothesis that dissimilatory sulfate reduction is limited by the availability of both sulfate and total organic carbon (TOC) in the sediment. The conceptual model also assumes that pore water sulfide concentrations are constrained by the availability of pore water iron and that sediment iron supports the supply of dissolved iron to the pore water. A key result from the SE model is that variations in three external variables (sulfate, sediment TOC, and sediment iron) contribute nearly equally to the observed variations in pore water sulfide. As a result, management efforts to mitigate against the toxic effects of pore water sulfide on macrophytes such as wild rice should approach defining a protective sulfate threshold as an exercise tailored to the geochemistry of each site that quantitatively considers the effects of ambient concentrations of sediment Fe and TOC.

  7. Structural evolution of the Kilombero rift basin in central Tanzania ...

    African Journals Online (AJOL)

    Detailed geological and structural investigations at the northwestern scarp of the Cenozoic Kilombero Rift allow the drawing of its structural evolution and establishment of stress conditions that prevailed at the different deformational episodes at this rift zone. The structure, where the northwestern scarp of the Cenozoic ...

  8. Evolution of structural and functional diversification among plant Argonautes.

    Science.gov (United States)

    Singh, Ravi K; Pandey, Shree P

    2015-01-01

    Argonautes (AGOs) are the effector proteins of the RNA-induced silencing (RISC) complex, formed during the phenomena of small-RNA mediated post-transcriptional gene silencing. AGOs are a large family of proteins; their number varies from a few (4 in Chlamydomonas reinhardtii) to many (18 in Oryza sativa) in plants. Genetics-guided analysis have demonstrated the roles of some of the AGOs during growth and development of plants. Biochemical studies have further revealed differences in functional specificities among AGOs. How the AGO family expanded in different plant species during the course of evolution is starting to emerge. We hypothesized that 4 classes of AGOs evolved after divergence of unicellular green algae when an ancestral AGO underwent duplication events. Evolution of multicellularity may have coincided with the diversification of AGOs. A comparative sequence and structure analysis of the plant AGOs, including those from the mosses and the unicellular algae, show not only conformational differences between those from lower and higher plants, but also functional divergence of important sites.

  9. Modeling Temporal Evolution and Multiscale Structure in Networks

    DEFF Research Database (Denmark)

    Herlau, Tue; Mørup, Morten; Schmidt, Mikkel Nørgaard

    2013-01-01

    Many real-world networks exhibit both temporal evolution and multiscale structure. We propose a model for temporally correlated multifurcating hierarchies in complex networks which jointly capture both effects. We use the Gibbs fragmentation tree as prior over multifurcating trees and a change......-point model to account for the temporal evolution of each vertex. We demonstrate that our model is able to infer time-varying multiscale structure in synthetic as well as three real world time-evolving complex networks. Our modeling of the temporal evolution of hierarchies brings new insights...

  10. Social network analysis community detection and evolution

    CERN Document Server

    Missaoui, Rokia

    2015-01-01

    This book is devoted to recent progress in social network analysis with a high focus on community detection and evolution. The eleven chapters cover the identification of cohesive groups, core components and key players either in static or dynamic networks of different kinds and levels of heterogeneity. Other important topics in social network analysis such as influential detection and maximization, information propagation, user behavior analysis, as well as network modeling and visualization are also presented. Many studies are validated through real social networks such as Twitter. This edit

  11. Evolution of camalexin and structurally related indolic compounds.

    Science.gov (United States)

    Rauhut, Thomas; Glawischnig, Erich

    2009-01-01

    Structurally related secondary products are rather rarely shared by organisms from different kingdoms. Consequently, the evolution of biosynthetic pathways of defence metabolites between distantly related organisms has not been broadly investigated. Thiazolylindoles are found in Arabidopsis thaliana, as the phytoalexin camalexin, and in a Streptomyces strain, which synthesizes a tumour-inhibitory derivative, designated BE-10988. Camalexin originates from cysteine and tryptophan, which is converted to indole-3-acetaldoxime and subsequently dehydrated to indole-3-acetonitrile. The metabolic origin of BE-10988 was determined by retrobiosynthetic NMR analysis and incorporation studies with direct precursors. Like camalexin, it is derived from tryptophan and cysteine. However, as BE-10988 is synthesized via indole-3-pyruvic acid, not via indole-3-acetaldoxime, independent mechanisms of tryptophan modification have evolved.

  12. A teaching module about stellar structure and evolution

    Science.gov (United States)

    Colantonio, Arturo; Galano, Silvia; Leccia, Silvio; Puddu, Emanuella; Testa, Italo

    2017-01-01

    In this paper, we present a teaching module about stellar structure, functioning and evolution. Drawing from literature in astronomy education, we designed the activities around three key ideas: spectral analysis, mechanical and thermal equilibrium, energy and nuclear reactions. The module is divided into four phases, in which the key ideas for describing stars' functioning and physical mechanisms are gradually introduced. The activities (20 hours) build on previously learned laws in mechanics, thermodynamics, and electromagnetism and help students combine them meaningfully in order to get a complete picture of processes that happens in stars. The module was piloted with two intact classes of secondary school students (N = 59 students, 17-18 years old), using a ten-question multiple-choice questionnaire as research instrument. Results support the effectiveness of the proposed activities. Implications for the teaching of advanced physics topics using stars as fruitful context are briefly discussed.

  13. Structural evolution of small ruthenium cluster anions

    Energy Technology Data Exchange (ETDEWEB)

    Waldt, Eugen [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Hehn, Anna-Sophia; Ahlrichs, Reinhart [Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany); Kappes, Manfred M.; Schooss, Detlef, E-mail: detlef.schooss@kit.edu [Institut für Nanotechnologie, Karlsruher Institut für Technologie, Postfach 3640, 76021 Karlsruhe (Germany); Institute für Physikalische Chemie, Karlsruher Institut für Technologie, Kaiserstrasse 12, 76128 Karlsruhe (Germany)

    2015-01-14

    The structures of ruthenium cluster anions have been investigated using a combination of trapped ion electron diffraction and density functional theory computations in the size range from eight to twenty atoms. In this size range, three different structural motifs are found: Ru{sub 8}{sup −}–Ru{sub 12}{sup −} have simple cubic structures, Ru{sub 13}{sup −}–Ru{sub 16}{sup −} form double layered hexagonal structures, and larger clusters form close packed motifs. For Ru{sub 17}{sup −}, we find hexagonal close packed stacking, whereas octahedral structures occur for Ru{sub 18}{sup −}–Ru{sub 20}{sup −}. Our calculations also predict simple cubic structures for the smaller clusters Ru{sub 4}{sup −}–Ru{sub 7}{sup −}, which were not accessible to electron diffraction measurements.

  14. Giant Planet Interior Structure and Thermal Evolution

    OpenAIRE

    Fortney, Jonathan J.; Baraffe, Isabelle; Militzer, Burkhard

    2009-01-01

    We discuss the interior structure and composition of giant planets, and how this structure changes as these planets cool and contract over time. Here we define giant planets as those that have an observable hydrogen-helium envelope, which includes Jupiter-like planets, which are predominantly H/He gas, and Neptune-like planets which are predominantly composed of elements heavier than H/He. We describe the equations of state of planetary materials and the construction of static structural mode...

  15. Structural evolution of Ti/TiC multilayers

    International Nuclear Information System (INIS)

    Dahan, I.; Frage, N.; Dariel, M.P.

    2004-01-01

    Hard coatings based on metal/ceramic multilayers with periods in the nanometer range have been shown to possess some potential for improved tribological and mechanical properties. The present work is concerned with the structural evolution of (Ti/TiC) multilayers. Two kinds of multilayers consisting of 30 equithick (40 nm)TiC layers and 20 and 60 nm thick Ti layers, respectively, were sputter deposited on Mo substrates. The structural and the compositional evolution of these multilayers were examined by x-ray diffraction, transition electron microscopy (TEM), high-resolution TEM, Auger electron microscopy spectroscopy and differential thermal analysis (DTA), in the as-deposited state and after various heat treatments up to 500 deg. C. Initially, the Ti layers had a crystalline columnar grain structure displaying a (002) texture. The TiC layers displayed weak crystallinity with a pronounced (111) texture. In the course of the heat treatments, carbon diffused from the carbide layer into the adjacent Ti layers transforming the latter into off-stoichiometric TiC x with x≅0.5 and simultaneously depleting the carbon content of the initial carbide layer. The formed TiC x layers maintained the textural relationship with the neighboring TiC layers, consistent with a transformation that involved only a ABAB to ABC stacking change of the Ti sublattice. Increased mobility of the Ti atoms in carbon-depleted original TiC layers led to their full or partial recrystallization. The thermal effects associated both with the transformation of Ti layers into TiC, due to the influx of carbon atoms, and with the recrystallization of the original TiC layers were clearly revealed by the DTA measurements

  16. Examining the evolution towards turbulence through spatio-temporal analysis of multi-dimensional structures formed by instability growth along a shear layer

    Science.gov (United States)

    Merritt, Elizabeth; Doss, Forrest; Loomis, Eric; Flippo, Kirk; Devolder, Barbara; Welser-Sherrill, Leslie; Fincke, James; Kline, John

    2014-10-01

    The counter-propagating shear campaign is examining instability growth and its transition to turbulence relevant to mix in ICF capsules. Experimental platforms on both OMEGA and NIF use anti-symmetric flows about a shear interface to examine isolated Kelvin-Helmholtz instability growth. Measurements of interface (an Al or Ti tracer layer) dynamics are used to benchmark the LANL RAGE hydrocode with BHR turbulence model. The tracer layer does not expand uniformly, but breaks up into multi-dimensional structures that are initially quasi-2D due to the target geometry. We are developing techniques to analyze the multi-D structure growth along the tracer surface with a focus on characterizing the time-dependent structures' spectrum of scales in order to appraise a transition to turbulence in the system and potentially provide tighter constraints on initialization schemes for the BHR model. To this end, we use a wavelet based analysis to diagnose single-time radiographs of the tracer layer surface (w/low and amplified roughness for random noise seeding) with observed spatially non-repetitive features, in order to identify spatial and temporal trends in radiographs taken at different times across several experimental shots. This work conducted under the auspices of the U.S. Department of Energy by LANL under Contract DE-AC52-06NA25396.

  17. Theoretical investigation on structural evolution, energetic stability ...

    Indian Academy of Sciences (India)

    Abstract. We systematically studied the geometrical structures, relative stabilities, electronic properties and chemical hardness of AunCd (n=1–12) clusters based on the framework of the density functional theory using relativistic all-electron methods. Low-lying energy structures include two-dimensional and three- ...

  18. Trichome structure and evolution in Neotropical lianas.

    Science.gov (United States)

    Nogueira, Anselmo; Ottra, Juliana Hanna Leite El; Guimarães, Elza; Machado, Silvia Rodrigues; Lohmann, Lúcia G

    2013-11-01

    Trichomes are epidermal outgrowths generally associated with protection against herbivores and/or desiccation that are widely distributed from ferns to angiosperms. Patterns of topological variation and morphological evolution of trichomes are still scarce in the literature, preventing valid comparisons across taxa. This study integrates detailed morphoanatomical data and the evolutionary history of the tribe Bignonieae (Bignoniaceae) in order to gain a better understanding of current diversity and evolution of trichome types. Two sampling schemes were used to characterize trichome types: (1) macromorphological characterization of all 105 species currently included in Bignonieae; and (2) micromorphological characterization of 16 selected species. Individual trichome morphotypes were coded as binary in each vegetative plant part, and trichome density and size were coded as multistate. Ancestral character state reconstructions were conducted using maximum likelihood (ML) assumptions. Two main functional trichome categories were found: non-glandular and glandular. In glandular trichomes, three morphotypes were recognized: peltate (Pg), stipitate (Sg) and patelliform/cupular (P/Cg) trichomes. Non-glandular trichomes were uniseriate, uni- or multicellular and simple or branched. Pg and P/Cg trichomes were multicellular and non-vascularized with three clearly distinct cell layers. Sg trichomes were multicellular, uniseriate and long-stalked. ML ancestral character state reconstructions suggested that the most recent common ancestor (MRCA) of Bignonieae probably had non-glandular, Pg and P/Cg trichomes, with each trichome type presenting alternative histories of appearance on the different plant parts. For example, the MRCA of Bignonieae probably had non-glandular trichomes on the stems, prophylls, petiole, petiolule and leaflet veins while P/Cg trichomes were restricted to leaflet blades. Sg trichomes were not present in the MRCA of Bignonieae independently of the

  19. Mixing biases: Structural changes in the as topology evolution

    NARCIS (Netherlands)

    Haddadi, H.; Fay, D.; Uhlig, S.; Moore, A.; Mortier, R.; Jamakovic, A.

    2010-01-01

    In this paper we study the structural evolution of the AS topology as inferred from two different datasets over a period of seven years. We use a variety of topological metrics to analyze the structural differences revealed in the AS topologies inferred from the two different datasets. In

  20. Structural evolution of western Fortuna Tessera, Venus

    Science.gov (United States)

    Pritchard, M. E.; Hansen, V. L.; Willis, J. J.

    1997-09-01

    Western Fortuna Tessera, Ishtar Terra, records polyphase deformation. Structures include: ribbons forming long, narrow, steep-sided troughs that reflect surface layer extension; N-trending folds related to Maxwell Montes deformation; short, wide, NW-trending graben that reflect late local extension; and, within the southwestern map area, gentle, E-trending warps, which postdate ribbon structures. Flood lava flows postdate deformation. Ribbon structures change orientation radially from NNE to WNW. These observations caution against the correlation of Fortuna Tessera with tessera elsewhere on Venus and against the proposal that tessera forms a global stratigraphic layer.

  1. [Blue blood: structure and evolution of hemocyanin].

    Science.gov (United States)

    Linzen, B

    1989-05-01

    Hemocyanins are the oxygen-transporting proteins in arthropods and molluscs, the oxygen is bound by two copper atoms. Spectroscopic studies on the active site show similarities to the active site of a further group of copper-containing proteins, the tyrosinases. Arthropodan and molluscan hemocyanins form high-molecular aggregates which are markedly different in size and quaternary structure. There is only one tertiary structure of an arthropodan hemocyanin available, but from comparison of all amino acid sequences known so far from arthropodan hemocyanins, a common tertiary structure for all arthropodan hemocyanins can be deduced. Again, sequence comparison allows the construction of an evolutionary tree for some oxygen-binding copper proteins.

  2. Structure and Evolution of Thermohaline Staircases in Tropical North Atlantic

    Science.gov (United States)

    2007-12-01

    series of mixed layers separated by sharp interfaces. The discovery of these ‘ thermohaline staircases’ by Tait and Howe (1968) further stimulated...EVOLUTION OF THERMOHALINE STAIRCASES IN TROPICAL NORTH ATLANTIC by Steven Wall December 2007 Thesis Advisor: Timour Radko Second Reader...DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Structure and Evolution of Thermohaline Staircases in Tropical North Atlantic 6. AUTHOR(S

  3. Structural analysis of DAEs

    DEFF Research Database (Denmark)

    Poulsen, Mikael Zebbelin

    2002-01-01

    , by the implementation of the Simpy tool box. This is an object oriented system implemented in the Python language. It can be used for analysis of DAEs, ODEs and non-linear equation and uses e.g. symbolic representations of expressions and equations. The presentations of theory and algorithms for structural index...... analysis of DAE is original in the sense that it is based on a new matrix representation of the structural information of a general DAE system instead of a graph oriented representation. Also the presentation of the theory is found to be more complete compared to other presentations, since it e.g. proves....... The methodology is mainly based on strutural index analysis which is not limited by the index of the DAE as other methodologies. As a result of structural index analysis one can perform index reduction of the DAE and obtain the so-called augmented underlying ODE. It is also described, how to use the augmented...

  4. Phylogeny, evolution and host-parasite relationships of the order Proteocephalidea (Eucestoda) as revealed by combined analysis and secondary structure characters

    Czech Academy of Sciences Publication Activity Database

    Hypša, Václav; Škeříková, Andrea; Scholz, Tomáš

    2005-01-01

    Roč. 130, č. 3 (2005), s. 359-371 ISSN 0031-1820 R&D Projects: GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z60220518 Keywords : phylogeny * co-evolution * Proteocephalidea Subject RIV: EG - Zoology Impact factor: 1.703, year: 2005

  5. Structure and Evolution of Package Dependency Networks

    NARCIS (Netherlands)

    Kikas, Riivo; Gousios, Giorgos; Dumas, Marlon; Pfahl, Dietmar; Bilof, R.

    Software developers often include available open-source software packages into their projects to minimize redundant effort. However, adding a package to a project can also introduce risks, which can propagate through multiple levels of dependencies. Currently, not much is known about the structure

  6. (ajst) structural evolution of bode saadu area

    African Journals Online (AJOL)

    opiyo

    Late brittle structures include transcurrent faults, both dextral and sinistral, which occasionally occurred in conjugate sets under generally N-S trending, maximum conpressive stress. INTRODUCTION. The Bode Saadu area forms part of the southwestern sector of the Nigerian basement complex which comprises. Archean ...

  7. Structural Approaches to Sequence Evolution Molecules, Networks, Populations

    CERN Document Server

    Bastolla, Ugo; Roman, H. Eduardo; Vendruscolo, Michele

    2007-01-01

    Structural requirements constrain the evolution of biological entities at all levels, from macromolecules to their networks, right up to populations of biological organisms. Classical models of molecular evolution, however, are focused at the level of the symbols - the biological sequence - rather than that of their resulting structure. Now recent advances in understanding the thermodynamics of macromolecules, the topological properties of gene networks, the organization and mutation capabilities of genomes, and the structure of populations make it possible to incorporate these key elements into a broader and deeply interdisciplinary view of molecular evolution. This book gives an account of such a new approach, through clear tutorial contributions by leading scientists specializing in the different fields involved.

  8. Structural analysis and Miocene-to-Present tectonic evolution of a lithospheric-scale, transcurrent lineament: The Sciacca Fault (Sicilian Channel, Central Mediterranean Sea)

    Science.gov (United States)

    Fedorik, Jakub; Toscani, Giovanni; Lodolo, Emanuele; Civile, Dario; Bonini, Lorenzo; Seno, Silvio

    2018-01-01

    Seismo-stratigraphic and structural analysis of a large number of multichannel seismic reflection profiles acquired in the northern part of the Sicilian Channel allowed a 3-D reconstruction of a regional NS-trending transfer zone which displays a transcurrent tectonic regime, and that is of broad relevance for its seismotectonic and geodynamic implications. It is constituted of two major transcurrent faults delimiting a 30-km-wide, mostly undeformed basin. The western fault (Capo Granitola) does not show clear evidence of present-day tectonic activity, and toward the south it is connected with the volcanic area of the Graham Bank. The eastern fault (Sciacca) is structurally more complex, showing active deformation at the sea-floor, particularly evident along the Nerita Bank. The Sciacca Fault is constituted of a master and splay faults compatible with a right-lateral kinematics. Sciacca Fault is superimposed on an inherited weakness zone (a Mesozoic carbonate ramp), which borders to the east a 2.5-km-thick Plio-Quaternary basin, and that was reactivated during the Pliocene. A set of scaled claybox analogue models was carried out in order to better understand the tectonic processes that led to the structural setting displayed by seismic data. Tectonic structures and uplift/subsidence patterns generated by the models are compatible with the 3-D model obtained from seismic reflection profiles. The best fit between the tectonic setting deriving from the interpretation of seismic profiles and the analogue models was obtained considering a right-lateral movement for the Sciacca Fault. Nevertheless, the stress field in the study area derived from GPS measurements does not support the present-day modelled right-lateral kinematics along the Sciacca Fault. Moreover, seismic events along this fault show focal mechanisms with a left-lateral component. We ascribe the slip change along the Sciacca Fault, from a right-lateral transcurrent regime to the present-day left

  9. Fermionic covariant prolongation structure theory for supernonlinear evolution equation

    International Nuclear Information System (INIS)

    Cheng Jipeng; Wang Shikun; Wu Ke; Zhao Weizhong

    2010-01-01

    We investigate the superprincipal bundle and its associated superbundle. The super(nonlinear)connection on the superfiber bundle is constructed. Then by means of the connection theory, we establish the fermionic covariant prolongation structure theory of the supernonlinear evolution equation. In this geometry theory, the fermionic covariant fundamental equations determining the prolongation structure are presented. As an example, the supernonlinear Schroedinger equation is analyzed in the framework of this fermionic covariant prolongation structure theory. We obtain its Lax pairs and Baecklund transformation.

  10. Planetary ring systems properties, structures, and evolution

    CERN Document Server

    Murray, Carl D

    2018-01-01

    Planetary rings are among the most intriguing structures of our solar system and have fascinated generations of astronomers. Collating emerging knowledge in the field, this volume reviews our current understanding of ring systems with reference to the rings of Saturn, Uranus, Neptune, and more. Written by leading experts, the history of ring research and the basics of ring–particle orbits is followed by a review of the known planetary ring systems. All aspects of ring system science are described in detail, including specific dynamical processes, types of structures, thermal properties and their origins, and investigations using computer simulations and laboratory experiments. The concluding chapters discuss the prospects of future missions to planetary rings, the ways in which ring science informs and is informed by the study of other astrophysical disks, and a perspective on the field's future. Researchers of all levels will benefit from this thorough and engaging presentation.

  11. Same Precursor, Two Different Products: Comparing the Structural Evolution of In–Ga–O “Gel-Derived” Powders and Solution-Cast Films Using Pair Distribution Function Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Suzannah R. [Department; Woods, Keenan N. [Department; Plassmeyer, Paul N. [Department; Marsh, David A. [Department; Johnson, Darren W. [Department; Page, Catherine J. [Department; Jensen, Kirsten M. Ø. [Department; Johnson, David C. [Department

    2017-04-03

    Amorphous metal oxides are central to a variety of technological applications. In particular, indium gallium oxide has garnered attention as a thin-film transistor channel layer material. In this work we examine the structural evolution of indium gallium oxide gel-derived powders and thin films using infrared vibrational spectroscopy, X-ray diffraction, and pair distribution function (PDF) analysis of X-ray total scattering from standard and normal incidence thin-film geometries (tfPDF). We find that the gel-derived powders and films from the same aqueous precursor evolve differently with temperature, forming mixtures of Ga-substituted In2O3 and In-substituted β-Ga2O3 with different degrees of substitution. X-ray total scattering and PDF analysis indicate that the majority phase for both the powders and films is an amorphous/nanocrystalline β-Ga2O3 phase, with a minor constituent of In2O3 with significantly larger coherence lengths. This amorphous β-Ga2O3 phase could not be identified using the conventional Bragg diffraction techniques traditionally used to study crystalline metal oxide thin films. The combination of Bragg diffraction and tfPDF provides a much more complete description of film composition and structure, which can be used to detail the effect of processing conditions and structure–property relationships. This study also demonstrates how structural features of amorphous materials, traditionally difficult to characterize by standard diffraction, can be elucidated using tfPDF.

  12. Island universes structure and evolution of disk galaxies

    CERN Document Server

    DE JONG, R. S

    2007-01-01

    This book contains an up-to-date review of the structure and evolution of disk galaxies from both the observational and theoretical point of view. The book is the proceedings of the "Island Universes" conference held at the island of Terschelling, The Netherlands in July 2005, which attracted about 130 experts and students in the field. The conference was organized as a tribute to Dr. Piet C. van der Kruit for receiving the honorary Jacobus C. Kapteyn Professorship in Astronomy. The eight topical themes discussed at the meeting are reflected in these proceedings: 1) Properties of Stellar Disks, 2) Kinematics and Dynamics of Disk Galaxies, 3) Bars, Spiral Structure, and Secular Evolution in Disk Galaxies, 4) The Outskirts and Environment of Disk Galaxies, 5) Interstellar Matter, 6) (Evolution of) Star Formation in Galactic Disks, 7) Disk Galaxies through Cosmic Time, and 8) Formation Models of Disk Galaxies. These proceedings are concluded with a conference summary reflecting on the most significant recent pro...

  13. Structure, Function, and Evolution of Rice Centromeres

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Jiming

    2010-02-04

    The centromere is the most characteristic landmark of eukaryotic chromosomes. Centromeres function as the site for kinetochore assembly and spindle attachment, allowing for the faithful pairing and segregation of sister chromatids during cell division. Characterization of centromeric DNA is not only essential to understand the structure and organization of plant genomes, but it is also a critical step in the development of plant artificial chromosomes. The centromeres of most model eukaryotic species, consist predominantly of long arrays of satellite DNA. Determining the precise DNA boundary of a centromere has proven to be a difficult task in multicellular eukaryotes. We have successfully cloned and sequenced the centromere of rice chromosome 8 (Cen8), representing the first fully sequenced centromere from any multicellular eukaryotes. The functional core of Cen8 spans ~800 kb of DNA, which was determined by chromatin immunoprecipitation (ChIP) using an antibody against the rice centromere-specific H3 histone. We discovered 16 actively transcribed genes distributed throughout the Cen8 region. In addition to Cen8, we have characterized eight additional rice centromeres using the next generation sequencing technology. We discovered four subfamilies of the CRR retrotransposon that is highly enriched in rice centromeres. CRR elements are constitutively transcribed and different CRR subfamilies are differentially processed by RNAi. These results suggest that different CRR subfamilies may play different roles in the RNAi-mediated pathway for formation and maintenance of centromeric chromatin.

  14. The evolution of song structure in southern African birds: an ...

    African Journals Online (AJOL)

    Song is critical to territory defence, mate attraction, and both species and individual recognition. According to the Acoustic Adaptation Hypothesis (AAH), habitat structure may exercise a selective force on vocal evolution such that song evolves to minimise the degradation and attenuation of acoustic signals in the particular ...

  15. Plant retroviruses: structure, evolution and future applications | Zaki ...

    African Journals Online (AJOL)

    Until recently, retroviruses were thought to be restricted to vertebrates. Plant sequencing projects revealed that plant genomes contain retroviral-like sequences. This review aims to address the structure and evolution of plant retroviruses. In addition, it proposes future applications for these important key components of plant ...

  16. Structures and morphotectonic evolution of the frontal fold–thrust ...

    Indian Academy of Sciences (India)

    52

    The differential movement of the mountain front on both sides of the ramp is decipherable. 23. This is especially true ..... Further movement along the Frontal Fault deformed Siwalik sediments. Siwalik sediments ..... Poblet J and Lisle R J 2011 Kinematic evolution and structural styles of fold-and-thrust belts;. 391. Geol. Soc.

  17. Nonlocalized clustering and evolution of cluster structure in nuclei

    Science.gov (United States)

    Horiuchi, H.

    2017-06-01

    It is shown that the THSR (Tohsaki-Horiuchi-Schuck-Roepke) wave function describe well not only cluster-gas like structures but also ordinary cluster structures with spatial localization of clusters. Based on this fact, the container model has been proposed as a new model of cluster dynamics. For better description of cluster dynamics, extended version of container model has been introduced. The container model of cluster dynamics teaches us how is the evolution of cluster structure which starts from the ground state having shell-model structure to many kinds of cluster states up to the cluster-gas states.

  18. COI Structural Analysis Presentation

    Science.gov (United States)

    Cline, Todd; Stahl, H. Philip (Technical Monitor)

    2001-01-01

    This report discusses the structural analysis of the Next Generation Space Telescope Mirror System Demonstrator (NMSD) developed by Composite Optics Incorporated (COI) in support of the Next Generation Space Telescope (NGST) project. The mirror was submitted to Marshall Space Flight Center (MSFC) for cryogenic testing and evaluation. Once at MSFC, the mirror was lowered to approximately 40 K and the optical surface distortions were measured. Alongside this experiment, an analytical model was developed and used to compare to the test results. A NASTRAN finite element model was provided by COI and a thermal model was developed from it. Using the thermal model, steady state nodal temperatures were calculated based on the predicted environment of the large cryogenic test chamber at MSFC. This temperature distribution was applied in the structural analysis to solve for the deflections of the optical surface. Finally, these deflections were submitted for optical analysis and comparison to the interferometer test data.

  19. Structural evolution of silica sols modified with formamide

    Directory of Open Access Journals (Sweden)

    Lenza R.F.S.

    2001-01-01

    Full Text Available In this work we investigated the influence of formamide on the acid-catalyzed sol-gel process by Fourier transform infrared spectroscopy (FTIR. Three silica sols were studied: Sol catalyzed with nitric acid without formamide, sol catalyzed with nitric acid containing formamide and sol catalyzed with a mixture of nitric acid and hydrofluoric acid and modified with formamide. Following the time evolution of both the Si-(OH stretching vibration at around 950 cm-1 and the Si-O-(Si vibration between 1040 cm-1 and 1200 cm-1 we were able to describe the structural evolution of each sol. The curve of evolution of Si-(OH stretching vibration corresponding to sol A has a simple asymptotic evolution. In the case of formamide containing sol, we observed a two-step structural evolution indicating that for the system containing formamide the polymerization goes through a temporary stabilization of oligomers, which can explain the non-variation of the Si-O(H bond wavenumber for a certain time. Gelation times were of several days for gels without formamide and few hours for gels containing additive. The presence of additive resulted in a highly interconnected gel.

  20. An analysis of synteny of Arachis with Lotus and Medicago sheds new light on the structure, stability and evolution of legume genomes

    Directory of Open Access Journals (Sweden)

    Nielsen Anna M

    2009-01-01

    Full Text Available Abstract Background Most agriculturally important legumes fall within two sub-clades of the Papilionoid legumes: the Phaseoloids and Galegoids, which diverged about 50 Mya. The Phaseoloids are mostly tropical and include crops such as common bean and soybean. The Galegoids are mostly temperate and include clover, fava bean and the model legumes Lotus and Medicago (both with substantially sequenced genomes. In contrast, peanut (Arachis hypogaea falls in the Dalbergioid clade which is more basal in its divergence within the Papilionoids. The aim of this work was to integrate the genetic map of Arachis with Lotus and Medicago and improve our understanding of the Arachis genome and legume genomes in general. To do this we placed on the Arachis map, comparative anchor markers defined using a previously described bioinformatics pipeline. Also we investigated the possible role of transposons in the patterns of synteny that were observed. Results The Arachis genetic map was substantially aligned with Lotus and Medicago with most synteny blocks presenting a single main affinity to each genome. This indicates that the last common whole genome duplication within the Papilionoid legumes predated the divergence of Arachis from the Galegoids and Phaseoloids sufficiently that the common ancestral genome was substantially diploidized. The Arachis and model legume genomes comparison made here, together with a previously published comparison of Lotus and Medicago allowed all possible Arachis-Lotus-Medicago species by species comparisons to be made and genome syntenies observed. Distinct conserved synteny blocks and non-conserved regions were present in all genome comparisons, implying that certain legume genomic regions are consistently more stable during evolution than others. We found that in Medicago and possibly also in Lotus, retrotransposons tend to be more frequent in the variable regions. Furthermore, while these variable regions generally have lower

  1. [Petrological Analysis of Astrophysical Dust Analog Evolution

    Science.gov (United States)

    Rietmeijer, Frans J. M.

    1997-01-01

    This project "Petrological analysis of astrophysical dust analog evolution" was initiated to try to understand the vapor phase condensation, and the nature of the reaction products, in circumstellar environments, such as the solar nebula 4,500 Myrs ago, and in the interstellar medium. Telescope-based infrared [IR] spectroscopy offers a broad-scale inventory of the various types of dust in these environments but no details on small-scale variations in terms of chemistry and morphology and petrological phase relationships. Vapor phase condensation in these environments is almost certainly a non-equilibrium process. The main challenge to this research was to document the nature of this process that, based on astrophysical observations, seems to yield compositionally consistent materials. This observation may suggest a predictable character during non-equilibrium condensation. These astrophysical environments include two chemically distinct, that is, oxygen-rich and carbon-rich environments. The former is characterized by silicates the latter by carbon-bearing solids. According to cosmological models of stellar evolution circumstellar dust accreted into protoplanets wherein thermal and/or aqueous processes will alter the dust under initially, non-equilibrium conditions.

  2. Parallel Evolution of Chromatin Structure Underlying Metabolic Adaptation.

    Science.gov (United States)

    Cheng, Jian; Guo, Xiaoxian; Cai, Pengli; Cheng, Xiaozhi; Piškur, Jure; Ma, Yanhe; Jiang, Huifeng; Gu, Zhenglong

    2017-11-01

    Parallel evolution occurs when a similar trait emerges in independent evolutionary lineages. Although changes in protein coding and gene transcription have been investigated as underlying mechanisms for parallel evolution, parallel changes in chromatin structure have never been reported. Here, Saccharomyces cerevisiae and a distantly related yeast species, Dekkera bruxellensis, are investigated because both species have independently evolved the capacity of aerobic fermentation. By profiling and comparing genome sequences, transcriptomic landscapes, and chromatin structures, we revealed that parallel changes in nucleosome occupancy in the promoter regions of mitochondria-localized genes led to concerted suppression of mitochondrial functions by glucose, which can explain the metabolic convergence in these two independent yeast species. Further investigation indicated that similar mutational processes in the promoter regions of these genes in the two independent evolutionary lineages underlay the parallel changes in chromatin structure. Our results indicate that, despite several hundred million years of separation, parallel changes in chromatin structure, can be an important adaptation mechanism for different organisms. Due to the important role of chromatin structure changes in regulating gene expression and organism phenotypes, the novel mechanism revealed in this study could be a general phenomenon contributing to parallel adaptation in nature. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. THE STRUCTURE, ORIGIN, AND EVOLUTION OF INTERSTELLAR HYDROCARBON GRAINS

    International Nuclear Information System (INIS)

    Chiar, J. E.; Ricca, A.; Tielens, A. G. G. M.; Adamson, A. J.

    2013-01-01

    Many materials have been considered for the carrier of the hydrocarbon absorption bands observed in the diffuse interstellar medium (ISM). In order to refine the model for ISM hydrocarbon grains, we analyze the observed aromatic (3.28, 6.2 μm) and aliphatic (3.4 μm) hydrocarbon absorption features in the diffuse ISM along the line of sight toward the Galactic center Quintuplet Cluster. Observationally, sp 2 bonds can be measured in astronomical spectra using the 6.2 μm CC aromatic stretch feature, whereas the 3.4 μm aliphatic feature can be used to quantify the fraction of sp 3 bonds. The fractional abundance of these components allows us to place the Galactic diffuse ISM hydrocarbons on a ternary phase diagram. We conclude that the Galactic hydrocarbon dust has, on average, a low H/C ratio and sp 3 content and is highly aromatic. We have placed the results of our analysis within the context of the evolution of carbon dust in the ISM. We argue that interstellar carbon dust consists of a large core of aromatic carbon surrounded by a thin mantle of hydrogenated amorphous carbon (a-C:H), a structure that is a natural consequence of the processing of stardust grains in the ISM.

  4. Structural Evolution of Q-Carbon and Nanodiamonds

    Science.gov (United States)

    Gupta, Siddharth; Bhaumik, Anagh; Sachan, Ritesh; Narayan, Jagdish

    2018-04-01

    This article provides insights pertaining to the first-order phase transformation involved in the growth of densely packed Q-carbon and nanodiamonds by nanosecond laser melting and quenching of diamond-like carbon (DLC) thin films. DLC films with different sp 3 content were melted rapidly in a controlled way in super-undercooled state and quenched, leading to formation of distinct nanostructures, i.e., nanodiamonds, Q-carbon, and Q-carbon nanocomposites. This analysis provides direct evidence of the dependence of the super-undercooling on the structural evolution of Q-carbon. Finite element heat flow calculations showed that the super-undercooling varies monotonically with the sp 3 content. The phenomenon of solid-liquid interfacial instability during directional solidification from the melt state is studied in detail. The resulting lateral segregation leads to formation of cellular filamentary Q-carbon nanostructures. The dependence of the cell size and wavelength at the onset of instability on the sp 3 content of DLC thin films was modeled based on perturbation theory.

  5. Structural evolution of zirconium carbide under ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gosset, D. [CEA Saclay, DEN/DMN/SRMA, F-91191 Gif/Yvette cedex (France)], E-mail: dominique.gosset@cea.fr; Dolle, M. [CEMES-CNRS (UPR 8011), BP 94347, F-31055 Toulouse cedex 4 (France); Simeone, D. [CEA Saclay, DEN/DMN/SRMA, F-91191 Gif/Yvette cedex (France); Baldinozzi, G. [SPMS, Ecole Centrale Paris, F-92295 Chatenay-Malabry cedex (France); Thome, L. [CSNSM, bat. 108, F-91405 Orsay (France)

    2008-02-15

    Zirconium carbide is one of the candidate materials to be used for some fuel components of the high temperature nuclear reactors planned in the frame of the Gen-IV project. Few data exist regarding its behaviour under irradiation. We have irradiated ZrC samples at room temperature with slow heavy ions (4 MeV Au, fluence from 10{sup 11} to 5 x 10{sup 15} cm{sup -2}) in order to simulate neutron irradiations. Grazing incidence X-Ray diffraction (GIXRD) and transmission electron microscopy (TEM) analysis have been performed in order to study the microstructural evolution of the material versus ion fluence. A high sensitivity to oxidation is observed with the formation of zirconia precipitates during the ion irradiations. Three damage stages are observed. At low fluence (<10{sup 12} cm{sup -2}), low modifications are observed. At intermediate fluence, high micro-strains appear together with small faulted dislocation loops. At the highest fluence (>10{sup 14} cm{sup -2}), the micro-strains saturate and the loops coalesce to form a dense dislocation network. No other structural modification is observed. The material shows a moderate cell parameter increase, corresponding to a 0.6 vol.% swelling, which saturates around 10{sup 14} ions/cm{sup 2}, i.e., a few Zr dpa. As a result, in spite of a strong covalent bonding component, ZrC seems to have a behaviour under irradiation close to cubic metals.

  6. Structural Evolution of Q-Carbon and Nanodiamonds

    Science.gov (United States)

    Gupta, Siddharth; Bhaumik, Anagh; Sachan, Ritesh; Narayan, Jagdish

    2018-01-01

    This article provides insights pertaining to the first-order phase transformation involved in the growth of densely packed Q-carbon and nanodiamonds by nanosecond laser melting and quenching of diamond-like carbon (DLC) thin films. DLC films with different sp 3 content were melted rapidly in a controlled way in super-undercooled state and quenched, leading to formation of distinct nanostructures, i.e., nanodiamonds, Q-carbon, and Q-carbon nanocomposites. This analysis provides direct evidence of the dependence of the super-undercooling on the structural evolution of Q-carbon. Finite element heat flow calculations showed that the super-undercooling varies monotonically with the sp 3 content. The phenomenon of solid-liquid interfacial instability during directional solidification from the melt state is studied in detail. The resulting lateral segregation leads to formation of cellular filamentary Q-carbon nanostructures. The dependence of the cell size and wavelength at the onset of instability on the sp 3 content of DLC thin films was modeled based on perturbation theory.

  7. A Technology Investigation Supporting Software Architecture and Analysis for Evolution

    National Research Council Canada - National Science Library

    Garlan, David

    2001-01-01

    In this report we summarize the approaches and result of the project "A Technology Investigation Supporting Software Architecture and Analysis for Evolution," carried out at Carnegie Mellon University...

  8. Evolution of nucleon structure functions in the Q2 range between 20 and 10 000 GeV2 from a new QCD analysis of neutrino data

    International Nuclear Information System (INIS)

    Bergsma, F.; Dorenbosch, J.; Allaby, J.V.; Amaldi, U.; Barbiellini, G.; Flegel, W.; Lanceri, L.; Metcalf, M.; Nieuwenhuis, C.; Panman, J.; Santoni, C.; Winter, K.; Abt, I.; Aspiazu, J.; Buesser, F.W.; Daumann, H.; Gall, P.D.; Hebbeker, T.; Niebergall, F.; Schuett, P.; Staehelin, P.; Barone, L.; Borgia, B.; Capone, A.; Diemoz, M.; Dore, U.; Ferroni, F.; Longo, E.; Luminari, L.; Monacelli, P.; De Notaristefani, F.; Rome Univ.; Valente, V.

    1985-01-01

    From the nucleon structure functions measured by the CHARM Collaboration in inclusive neutrino and antineutrino CC interactions we determined the QCD parameter Λsub(MS) = 310 +- 140 (stat.) +- 70 (syst.) MeV using the Furmanski-Petronzio method. With the same method we extrapolated the behaviour of the quark (q + q) and the gluon x-distributions up to Q 2 = 10000 GeV 2 using perturbative QCD. The extrapolated structure functions are compared with recent results coming from the two-jet differential cross section in proton-antiproton interactions at √s = 540 GeV and Q 2 = 2000 GeV 2 . (orig.)

  9. Subsurface defects structural evolution in nano-cutting of single crystal copper

    International Nuclear Information System (INIS)

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Sun, Yazhou; Guo, Yongbo; Liang, Yingchun

    2015-01-01

    Highlights: • An innovative analysis method is adopted to analyze nano-cutting process accurately. • A characteristic SFT and stair-rod dislocation are found in subsurface defect layer. • The formation mechanism of stair-rod dislocation is investigated. • The local atomic structure of subsurface defects is introduced. - Abstract: In this work, molecular dynamics simulation is performed to study the subsurface defects structural distribution and its evolution during nano-cutting process of single crystal copper. The formation mechanism of chip and machined surface is interviewed by analyzing the dislocation evolution and atomic migration. The centro-symmetry parameter and spherical harmonics method are adopted to characterize the distribution and evolution of the subsurface defect structures and local atomic structures. The results show that stacking faults, dislocation loops, “V-shaped” dislocation loops, and plenty of point defects are formed during the machined surface being formed in shear-slip zone. In subsurface damage layers, stair-rod dislocation, stacking fault tetrahedra, atomic cluster defect, and vacancy defect are formed. And the formation mechanism of stair-rod dislocation is investigated by atomic-scale structure evolution. The local atomic structures of subsurface defects are icosahedrons, hexagonal close packed, body-centered cubic, and defect face center cubic, and the variations of local atomic structures are investigated

  10. Structuring evolution: biochemical networks and metabolic diversification in birds.

    Science.gov (United States)

    Morrison, Erin S; Badyaev, Alexander V

    2016-08-25

    Recurrence and predictability of evolution are thought to reflect the correspondence between genomic and phenotypic dimensions of organisms, and the connectivity in deterministic networks within these dimensions. Direct examination of the correspondence between opportunities for diversification imbedded in such networks and realized diversity is illuminating, but is empirically challenging because both the deterministic networks and phenotypic diversity are modified in the course of evolution. Here we overcome this problem by directly comparing the structure of a "global" carotenoid network - comprising of all known enzymatic reactions among naturally occurring carotenoids - with the patterns of evolutionary diversification in carotenoid-producing metabolic networks utilized by birds. We found that phenotypic diversification in carotenoid networks across 250 species was closely associated with enzymatic connectivity of the underlying biochemical network - compounds with greater connectivity occurred the most frequently across species and were the hotspots of metabolic pathway diversification. In contrast, we found no evidence for diversification along the metabolic pathways, corroborating findings that the utilization of the global carotenoid network was not strongly influenced by history in avian evolution. The finding that the diversification in species-specific carotenoid networks is qualitatively predictable from the connectivity of the underlying enzymatic network points to significant structural determinism in phenotypic evolution.

  11. The Structure and Evolution of the Strategic Management Field: A Content Analysis of Twenty-six Years of Strategic Management Research

    OpenAIRE

    Furrer,Olivier; Thomas, Howard; Goussevskaia, Anna

    2014-01-01

    This paper analyses 26 years of strategic management research published in Academy of Management Journal, Academy of Management Review, Administrative Science Quarterly and Strategic Management Journal. Through a content analysis, it studies the relationships between the subfields of strategic management. A multiple correspondence analysis provides a map of keywords and authors, and a framework to track this literature over the 26-year period. A discussion of future pathways in the strategic ...

  12. Computational Analysis for Morphological Evolution in Pyrolysis for Micro/Nanofabrication

    Directory of Open Access Journals (Sweden)

    Myeongseok Yang

    2015-01-01

    Full Text Available Pyrolysis is recently proposed as an efficient fabrication technique of micro/nanoscale carbon structures. In order to understand the morphological evolution in pyrolysis and design the final shape of carbon structure, this study proposes a comprehensive model that incorporates the essential mechanisms of pyrolysis based on the phase field framework. Computational analysis with the developed model provides information about the effect of interface energy and kinetic rate on the morphological evolution in pyrolysis.

  13. Evolution of single-particle structure of silicon isotopes

    Science.gov (United States)

    Bespalova, O. V.; Fedorov, N. A.; Klimochkina, A. A.; Markova, M. L.; Spasskaya, T. I.; Tretyakova, T. Yu.

    2018-01-01

    New data on proton and neutron single-particle energies E_{nlj} of Si isotopes with neutron number N from 12 to 28 as well as occupation probabilities N_{nlj} of single-particle states of stable isotopes 28, 30Si near the Fermi energy were obtained by the joint evaluation of the stripping and pick-up reaction data and excited state decay schemes of neighboring nuclei. The evaluated data indicate the following features of single-particle structure evolution: persistence of Z = 14 subshell closure with N increase, the new magicity of the number N = 16, and the conservation of the magic properties of the number N = 20 in Si isotopic chain. The features were described by the dispersive optical model. The calculation also predicts the weakening of N = 28 shell closure and demonstrates evolution of a bubble-like structure of the proton density distributions in neutron-rich Si isotopes.

  14. Structure and evolution of barley powdery mildew effector candidates

    Directory of Open Access Journals (Sweden)

    Pedersen Carsten

    2012-12-01

    Full Text Available Abstract Background Protein effectors of pathogenicity are instrumental in modulating host immunity and disease resistance. The powdery mildew pathogen of grasses Blumeria graminis causes one of the most important diseases of cereal crops. B. graminis is an obligate biotrophic pathogen and as such has an absolute requirement to suppress or avoid host immunity if it is to survive and cause disease. Results Here we characterise a superfamily predicted to be the full complement of Candidates for Secreted Effector Proteins (CSEPs in the fungal barley powdery mildew parasite B. graminis f.sp. hordei. The 491 genes encoding these proteins constitute over 7% of this pathogen’s annotated genes and most were grouped into 72 families of up to 59 members. They were predominantly expressed in the intracellular feeding structures called haustoria, and proteins specifically associated with the haustoria were identified by large-scale mass spectrometry-based proteomics. There are two major types of effector families: one comprises shorter proteins (100–150 amino acids, with a high relative expression level in the haustoria and evidence of extensive diversifying selection between paralogs; the second type consists of longer proteins (300–400 amino acids, with lower levels of differential expression and evidence of purifying selection between paralogs. An analysis of the predicted protein structures underscores their overall similarity to known fungal effectors, but also highlights unexpected structural affinities to ribonucleases throughout the entire effector super-family. Candidate effector genes belonging to the same family are loosely clustered in the genome and are associated with repetitive DNA derived from retro-transposons. Conclusions We employed the full complement of genomic, transcriptomic and proteomic analyses as well as structural prediction methods to identify and characterize the members of the CSEPs superfamily in B. graminis f

  15. Structure and evolution of barley powdery mildew effector candidates

    Science.gov (United States)

    2012-01-01

    Background Protein effectors of pathogenicity are instrumental in modulating host immunity and disease resistance. The powdery mildew pathogen of grasses Blumeria graminis causes one of the most important diseases of cereal crops. B. graminis is an obligate biotrophic pathogen and as such has an absolute requirement to suppress or avoid host immunity if it is to survive and cause disease. Results Here we characterise a superfamily predicted to be the full complement of Candidates for Secreted Effector Proteins (CSEPs) in the fungal barley powdery mildew parasite B. graminis f.sp. hordei. The 491 genes encoding these proteins constitute over 7% of this pathogen’s annotated genes and most were grouped into 72 families of up to 59 members. They were predominantly expressed in the intracellular feeding structures called haustoria, and proteins specifically associated with the haustoria were identified by large-scale mass spectrometry-based proteomics. There are two major types of effector families: one comprises shorter proteins (100–150 amino acids), with a high relative expression level in the haustoria and evidence of extensive diversifying selection between paralogs; the second type consists of longer proteins (300–400 amino acids), with lower levels of differential expression and evidence of purifying selection between paralogs. An analysis of the predicted protein structures underscores their overall similarity to known fungal effectors, but also highlights unexpected structural affinities to ribonucleases throughout the entire effector super-family. Candidate effector genes belonging to the same family are loosely clustered in the genome and are associated with repetitive DNA derived from retro-transposons. Conclusions We employed the full complement of genomic, transcriptomic and proteomic analyses as well as structural prediction methods to identify and characterize the members of the CSEPs superfamily in B. graminis f.sp. hordei. Based on relative

  16. Structure and evolution of 3D Rossby Vortices

    Science.gov (United States)

    Richard, S.; Barge, P.

    2013-04-01

    Three dimensional compressible simulations of the Rossby Wave Instability are presented in a non-homentropic model of protoplanetary disk. The instability develops like in the two dimensional case, gradually coming to the formation of a single big vortex. This 3D vortex has a quasi-2D structure which looks like a vorticity column with only tiny vertical motions. The vortex survives hundred of rotations in a quasi-steady evolution and slowly migrates inward toward the star.

  17. Evolution of Analysis of Polyhenols from Grapes, Wines, and Extracts

    Directory of Open Access Journals (Sweden)

    Pierre-Louis Teissedre

    2013-01-01

    Full Text Available Grape and wine phenolics are structurally diverse, from simple molecules to oligomers and polymers usually designated as tannins. They have an important impact on the organoleptic properties of wines, that’s why their analysis and quantification are of primordial importance. The extraction of phenolics from grapes and from wines is the first step involved in the analysis. Then, several analytical methods have been developed for the determination of total content of phenolic, while chromatographic and spectrophotometric analyses are continuously improved in order to achieve adequate separation of phenolic molecules, their subsequent identification and quantification. This review provides a summary of evolution of analysis of polyphenols from grapes, wines and extracts.

  18. Spectral phasor analysis of LAURDAN fluorescence in live A549 lung cells to study the hydration and time evolution of intracellular lamellar body-like structures

    DEFF Research Database (Denmark)

    Malacrida, Leonel; Astrada, Soledad; Briva, Arturo

    2016-01-01

    Using LAURDAN spectral imaging and spectral phasor analysis we concurrently studied the growth and hydration state of subcellular organelles (lamellar body-like, LB-like) from live A549 lung cancer cells at different post-confluence days. Our results reveal a time dependent two-step process...

  19. Analysis of the complete DNA sequence of the temperate bacteriophage TP901-1: Evolution, structure, and genome organization of lactococcal bacteriophages

    DEFF Research Database (Denmark)

    Brøndsted, Lone; Østergaard, Solvej; Pedersen, Margit

    2001-01-01

    A complete analysis of the entire genome of the temperate lactococcal bacteriophage TP901-1 has been performed and the function of 21 of 56 TP901-1-encoded ORFs has been assigned. This knowledge has been used to propose 10 functional modules each responsible for specific functions during bacterio...

  20. PROTOPLANETARY DISK STRUCTURE WITH GRAIN EVOLUTION: THE ANDES MODEL

    International Nuclear Information System (INIS)

    Akimkin, V.; Wiebe, D.; Pavlyuchenkov, Ya.; Zhukovska, S.; Semenov, D.; Henning, Th.; Vasyunin, A.; Birnstiel, T.

    2013-01-01

    We present a self-consistent model of a protoplanetary disk: 'ANDES' ('AccretioN disk with Dust Evolution and Sedimentation'). ANDES is based on a flexible and extendable modular structure that includes (1) a 1+1D frequency-dependent continuum radiative transfer module, (2) a module to calculate the chemical evolution using an extended gas-grain network with UV/X-ray-driven processes and surface reactions, (3) a module to calculate the gas thermal energy balance, and (4) a 1+1D module that simulates dust grain evolution. For the first time, grain evolution and time-dependent molecular chemistry are included in a protoplanetary disk model. We find that grain growth and sedimentation of large grains onto the disk midplane lead to a dust-depleted atmosphere. Consequently, dust and gas temperatures become higher in the inner disk (R ∼ 50 AU), in comparison with the disk model with pristine dust. The response of disk chemical structure to the dust growth and sedimentation is twofold. First, due to higher transparency a partly UV-shielded molecular layer is shifted closer to the dense midplane. Second, the presence of big grains in the disk midplane delays the freeze-out of volatile gas-phase species such as CO there, while in adjacent upper layers the depletion is still effective. Molecular concentrations and thus column densities of many species are enhanced in the disk model with dust evolution, e.g., CO 2 , NH 2 CN, HNO, H 2 O, HCOOH, HCN, and CO. We also show that time-dependent chemistry is important for a proper description of gas thermal balance.

  1. Structured Analysis - IDEF0

    DEFF Research Database (Denmark)

    Larsen, Michael Holm

    1999-01-01

    This note introduces the IDEF0 modelling language (semantics and syntax), and associated rules and techniques, for developing structured graphical representations of a system or enterprise. Use of this standard for IDEF0 permits the construction of models comprising system functions (activities...... that require a modelling technique for the analysis, development, re-engineering, integration, or acquisition of information systems; and incorporate a systems or enterprise modelling technique into a business process analysis or software engineering methodology.This note is a summary of the Standard...... for Integration Definition for Function Modelling (IDEF0). I.e. the Draft Federal Information Processing Standards Publication 183, 1993, December 21, Announcing the Standard for Integration Definition for Function Modelling (IDEF0)....

  2. SAXS observation of structural evolution of heated olefin

    International Nuclear Information System (INIS)

    Sun Minhua; Mou Hongchen; Wang Yuxi; Li Demin; Wang Aiping; Ma Congxiao; Cheng Weidong; Wang Dan; Liu Jia

    2007-01-01

    Structural evolution of olefin during its heating process was observed with SAXS method at Beijing Synchrotron Radiation Facility. The mean square fluctuation of electron density increased from 468.5 nm -2 at 22 degree C to 2416 nm -2 at 100 degree C, while the electronic gyration radius decreased from 11.61 nm at 22 degree C to 11.16 nm at 100 degree C. Therefore, the olefin softens as a result of the increased thermal motion of the molecules, rather than the shrinking size of fundamental structural units of olefin. (authors)

  3. Structure of the scientific community modelling the evolution of resistance.

    Science.gov (United States)

    2007-12-05

    Faced with the recurrent evolution of resistance to pesticides and drugs, the scientific community has developed theoretical models aimed at identifying the main factors of this evolution and predicting the efficiency of resistance management strategies. The evolutionary forces considered by these models are generally similar for viruses, bacteria, fungi, plants or arthropods facing drugs or pesticides, so interaction between scientists working on different biological organisms would be expected. We tested this by analysing co-authorship and co-citation networks using a database of 187 articles published from 1977 to 2006 concerning models of resistance evolution to all major classes of pesticides and drugs. These analyses identified two main groups. One group, led by ecologists or agronomists, is interested in agricultural crop or stock pests and diseases. It mainly uses a population genetics approach to model the evolution of resistance to insecticidal proteins, insecticides, herbicides, antihelminthic drugs and miticides. By contrast, the other group, led by medical scientists, is interested in human parasites and mostly uses epidemiological models to study the evolution of resistance to antibiotic and antiviral drugs. Our analyses suggested that there is also a small scientific group focusing on resistance to antimalaria drugs, and which is only poorly connected with the two larger groups. The analysis of cited references indicates that each of the two large communities publishes its research in a different set of literature and has its own keystone references: citations with a large impact in one group are almost never cited by the other. We fear the lack of exchange between the two communities might slow progress concerning resistance evolution which is currently a major issue for society.

  4. Spatiotemporal Diffusive Evolution and Fractal Structure of Ground Motion

    Science.gov (United States)

    Suwada, Tsuyoshi

    2018-02-01

    The spatiotemporal diffusive evolution and fractal structure of ground motion have been investigated at the in-ground tunnel of the KEK B-Factory (KEKB) injector linear accelerator (linac). The slow dynamic fluctuating displacements of the tunnel floor are measured in real time with a new remote-controllable sensing system based on a laser-based alignment system. Based on spatiotemporal analyses with linear-regression models, which were applied in both the time and frequency domains to time-series data recorded over a period of approximately 8 months, both coherent and stochastic components in the displacements of the tunnel floor were clearly observed along the entire length of the linac. In particular, it was clearly observed that the stochastic components exhibited characteristic spatiotemporal diffusive evolution with the fractal structure and fractional dimension. This report describes in detail the experimental techniques and analyses of the spatiotemporal diffusive evolution of ground motion observed at the in-ground tunnel of the injector linac using a real-time remote-controllable sensing system.

  5. Effect of PE on the structural evolution of iPP : analysis of a series of iPP-PE copolymers

    Science.gov (United States)

    Tenneti, Kishore; Tso, Chung; Li, Christopher

    2005-03-01

    The three different morphological forms of isotactic polypropylene (iPP), namely alpha, beta, and gamma, are well established. Alpha is the most common crystal phase while beta is metastable. The gamma form of iPP often exists as the minor component, intermixed with the alpha phase, during crystallization of copolymers at atmospheric pressures. A series of iPP-Polyethylene (PE) copolymers with varying percentages of PE have been investigated. Thermal and x-ray analysis reveal that as the PE content increases from 0 to 5 percent, gamma became the dominant phase. Single crystal morphology of the iPP-PE copolymers have been studied using TEM, SEM and AFM. The signature of alpha phase, the cross-hatch morphology, was observed in all the samples. Gamma single crystals were clearly observed like a ribbon shape and the center of the ribbon consisted of alpha lath. Fractal-like growth was also observed, presumably due to the thermal degradation of the polymer.

  6. Structural evolution and diversity of the caterpillar trunk

    DEFF Research Database (Denmark)

    Dupont, Steen Thorleif

    identify possible ground plan characteristics of the Lepidoptera and Amphiesmenoptera (MS1), 2) to describe and understand the evolution of the neolepidopteran caterpillar, and in particularly its crochet-bearing prolegs that are closely linked to walking on silken substrates and an external arboreal......The thesis explores some major transformation series in the structure of the lepidopteran larval trunk, focusing partly on the initial events in the evolution of the order, partly on one of the more spectacular cases of subsequent biological diversification within ‘typical’/’higher’ Lepidoptera...... morphology in an attempt to link form and function (MS2-3). 4) to re-evaluate the previously indicated correlation between the cuticle thickness of lycaenid larvae and the degree of myrmecophily in a selection of species in this family, and through a comparative study to better understand the link between...

  7. [Analysis on property of meridian supramolecules by biological evolution path].

    Science.gov (United States)

    Deng, Kaiwen; Tao, Yeqin; Tang, Wenhan; He, Fuyuan; Liu, Wenlong; Shi, Jilian; Yang, Yantao; Zhou, Yiqun; Chang, Xiaorong

    2017-03-12

    With human placed in the whole nature, by following the biologic evolution path, the property of channel structure for "imprinting template" in meridian and zang-fu was explored with supramolecular chemistry. In the history of biologic evolution, each molecule in "molecule society" gradually developed into various highly-ordered supramolecular bodies based on self-identification, self-assembly, self-organization, self-replicating of"imprinting template", and thereby the original biochemical system was established, and finally evolved into human. In the forming process of supramolecular bodies, the channel structure of"imprinting template" in guest supramolecular bodies would be kept by host supramolecular bodies, and communicate with the outside to exchange materials, energy, information, otherwise life phenomenon could not continue, for which it was the chemical nature of biolo-gical supramolecular bodies for body to develop meridian. Therefore, the human was a gigantic and complicated supramolecules body in biological nature, and possessed the supramolecules "imprinting template" at each stage of evolution, for which the meridians were formed. When meridians converged, acupoints appeared; when acupointsconverged, zang-fu appeared. With the promotion of the blood from heart, according to"imprinting template", the guest supramolecular bodies and host meridian produced qi -analysis, which was the qi -phenomenon of guest in meridian. It presented as zang-fu image of physiology and pathology as well as action regularities of medication and acupuncture tolerance, by which current various meridian viewpoints could be explained and propose the hypothesis of meridian supramolecular bodies. The meridian and its phenomenon was decide by its "imprinting template" of supramolecular bodies and self-reaction regularities, which abided through the living nature. This was the substance for meridian biology.

  8. Learning structural bioinformatics and evolution with a snake puzzle

    Directory of Open Access Journals (Sweden)

    Gonzalo S. Nido

    2016-12-01

    Full Text Available We propose here a working unit for teaching basic concepts of structural bioinformatics and evolution through the example of a wooden snake puzzle, strikingly similar to toy models widely used in the literature of protein folding. In our experience, developed at a Master’s course at the Universidad Autónoma de Madrid (Spain, the concreteness of this example helps to overcome difficulties caused by the interdisciplinary nature of this field and its high level of abstraction, in particular for students coming from traditional disciplines. The puzzle will allow us discussing a simple algorithm for finding folded solutions, through which we will introduce the concept of the configuration space and the contact matrix representation. This is a central tool for comparing protein structures, for studying simple models of protein energetics, and even for a qualitative discussion of folding kinetics, through the concept of the Contact Order. It also allows a simple representation of misfolded conformations and their free energy. These concepts will motivate evolutionary questions, which we will address by simulating a structurally constrained model of protein evolution, again modelled on the snake puzzle. In this way, we can discuss the analogy between evolutionary concepts and statistical mechanics that facilitates the understanding of both concepts. The proposed examples and literature are accessible, and we provide supplementary material (see ‘Data Availability’ to reproduce the numerical experiments. We also suggest possible directions to expand the unit. We hope that this work will further stimulate the adoption of games in teaching practice.

  9. Cenozoic structures and the tectonic evolution of the eastern North Sea

    DEFF Research Database (Denmark)

    Clausen, O.R.; Nielsen, S.B.; Egholm, D.L.

    2011-01-01

    Abundant seismic sections and well data from the Cenozoic succession in the eastern North Sea area generally reveal normal faulting, salt tectonics and localized tectonic inversion. However, inferences on the Cenozoic dynamic evolution of the region require thorough analysis of interactions between...... or cover tectonism took place. Our objectives are thus 1) to analyze the interaction between basement and cover structures, and if possible 2) to relate the structures to the regional tectonic evolution. The Zechstein evaporites pinch out onto the Ringkøbing-Fyn High, which in the eastern North Sea...... including decompaction in the Central Graben along the Arne-Elin trend shows that two phases of basement related inversion took place duringthe Paleocene-Eocene and the Oligocene. Halokinetics and differential compaction across the Paleogene inversion structure explain later tectonic signals...

  10. Phase analysis of amplitude binary mask structures

    Science.gov (United States)

    Puthankovilakam, Krishnaparvathy; Scharf, Toralf; Herzig, Hans Peter; Vogler, Uwe; Bramati, Arianna; Voelkel, Reinhard

    2016-03-01

    Shaping of light behind masks using different techniques is the milestone of the printing industry. The aerial image distribution or the intensity distribution at the printing distances defines the resolution of the structure after printing. Contrast and phase are the two parameters that play a major role in shaping of light to get the desired intensity pattern. Here, in contrast to many other contributions that focus on intensity, we discuss the phase evolution for different structures. The amplitude or intensity characteristics of the structures in a binary mask at different proximity gaps have been analyzed extensively for many industrial applications. But the phase evolution from the binary mask having OPC structures is not considered so far. The mask we consider here is the normal amplitude binary mask but having high resolution Optical Proximity Correction (OPC) structures for corners. The corner structures represent a two dimensional problem which is difficult to handle with simple rules of phase masks design and therefore of particular interest. The evolution of light from small amplitude structures might lead to high contrast by creating sharp phase changes or phase singularities which are points of zero intensity. We show the phase modulation at different proximity gaps and can visualize the shaping of light according to the phase changes. The analysis is done with an instrument called High Resolution Interference Microscopy (HRIM), a Mach-Zehnder interferometer that gives access to three-dimensional phase and amplitude images. The current paper emphasizes on the phase measurement of different optical proximity correction structures, and especially on corners of a binary mask.

  11. Origin, Internal Structure and Evolution of 4 Vesta

    Science.gov (United States)

    Zuber, Maria T.; McSween, Harry Y.; Binzel, Richard P.; Elkins-Tanton, Linda T.; Konopliv, Alexander S.; Pieters, Carle M.; Smith, David E.

    2011-12-01

    Asteroid 4 Vesta is the only preserved intact example of a large, differentiated protoplanet like those believed to be the building blocks of terrestrial planet accretion. Vesta accreted rapidly from the solar nebula in the inner asteroid belt and likely melted due to heat released due to the decay of 26Al. Analyses of meteorites from the howardite-eucrite-diogenite (HED) suite, which have been both spectroscopically and dynamically linked to Vesta, lead to a model of the asteroid with a basaltic crust that overlies a depleted peridotitic mantle and an iron core. Vesta’s crust may become more mafic with depth and might have been intruded by plutons arising from mantle melting. Constraints on the asteroid’s moments of inertia from the long-wavelength gravity field, pole position and rotation, informed by bulk composition estimates, allow tradeoffs between mantle density and core size; cores of up to half the planetary radius can be consistent with plausible mantle compositions. The asteroid’s present surface is expected to consist of widespread volcanic terrain, modified extensively by impacts that exposed the underlying crust or possibly the mantle. Hemispheric heterogeneity has been observed by poorly resolved imaging of the surface that suggests the possibility of a physiographic dichotomy as occurs on other terrestrial planets. Vesta might have had an early magma ocean but details of the early thermal structure are far from clear owing to model uncertainties and paradoxical observations from the HEDs. Petrological analysis of the eucrites coupled with thermal evolution modeling recognizes two possible mechanisms of silicate-metal differentiation leading to the formation of the basaltic achondrites: equilibrium partial melting or crystallization of residual liquid from the cooling magma ocean. A firmer understanding the plethora of complex physical and chemical processes that contribute to melting and crystallization will ultimately be required to

  12. Study of grain structure evolution during annealing of a twin-roll-cast Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, A. [IITB-Monash Research Academy, IIT Bombay (India); Department of Metallurgical Engineering and Materials Science, IIT Bombay (India); Department of Materials Engineering, Monash University (Australia); Samajdar, I. [Department of Metallurgical Engineering and Materials Science, IIT Bombay (India); Nie, J.F. [Department of Materials Engineering, Monash University (Australia); Tewari, A., E-mail: asim.tewari@iitb.ac.in [Department of Mechanical Engineering, IIT Bombay (India)

    2016-04-15

    The evolution of microstructure under static annealing was studied for mid-thickness section of a twin-roll-cast (TRC) magnesium alloy. Annealing was performed at 300 °C and 500 °C for different times. Microstructural evolution was quantitatively analyzed, from optical micrographs, using grain path envelope analysis. Additional information from electron backscatter diffraction (EBSD) was used for addressing the possible mechanism(s). It was found that the TRC structure had a bimodal grain size, which was preserved even after annealing at 300 °C. However, the annealing at 500 °C led to a unimodal grain size. This difference in the grain size distribution created a contrasting behavior in the normalized standard deviations. This was primarily attributed to a competition between recovery and recrystallization, and their respective dominance at 300° and 500 °C. A deformation induced recrystallization recovery (DIRR) model was proposed. The proposed model could successfully address the experimental microstructural evolution. - Highlights: • Annealing of twin roll cast (TRC) magnesium alloy was done at temperatures of 300 °C and 500 °C. • TRC had bimodal structure. Bimodality preserved for annealing at 300 °C. Annealing at 500 °C led to unimodal structure. • Grain evolution was described based on the competition between recovery and recrystallization. • Deformation induced recrystallization recovery (DIRR) mechanistic model was developed.

  13. Study of grain structure evolution during annealing of a twin-roll-cast Mg alloy

    International Nuclear Information System (INIS)

    Tripathi, A.; Samajdar, I.; Nie, J.F.; Tewari, A.

    2016-01-01

    The evolution of microstructure under static annealing was studied for mid-thickness section of a twin-roll-cast (TRC) magnesium alloy. Annealing was performed at 300 °C and 500 °C for different times. Microstructural evolution was quantitatively analyzed, from optical micrographs, using grain path envelope analysis. Additional information from electron backscatter diffraction (EBSD) was used for addressing the possible mechanism(s). It was found that the TRC structure had a bimodal grain size, which was preserved even after annealing at 300 °C. However, the annealing at 500 °C led to a unimodal grain size. This difference in the grain size distribution created a contrasting behavior in the normalized standard deviations. This was primarily attributed to a competition between recovery and recrystallization, and their respective dominance at 300° and 500 °C. A deformation induced recrystallization recovery (DIRR) model was proposed. The proposed model could successfully address the experimental microstructural evolution. - Highlights: • Annealing of twin roll cast (TRC) magnesium alloy was done at temperatures of 300 °C and 500 °C. • TRC had bimodal structure. Bimodality preserved for annealing at 300 °C. Annealing at 500 °C led to unimodal structure. • Grain evolution was described based on the competition between recovery and recrystallization. • Deformation induced recrystallization recovery (DIRR) mechanistic model was developed.

  14. Population Thinking, Price’s Equation and the Analysis of Economic Evolution

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    2004-01-01

    applicable to economic evolution due to the development of what may be called a general evometrics. Central to this evometrics is a method for partitioning evolutionary change developed by George Price into the selection effect and what may be called the innovation effect. This method serves surprisingly...... well as a means of accounting for evolution and as a starting point for the explanation of evolution. The applications of Price’s equation cover the partitioning and analysis of relatively short-term evolutionary change within individual industries as well as the study of more complexly structured...

  15. Nonlinear Structural Analysis

    Indian Academy of Sciences (India)

    This special issue of Sadhana is a collection of five papers selected from those presented at the Eighth National Seminar on Aerospace Structures (8th NASAS) organised by and held at the Indian Institute of Technology Madras, Chennai, on 9±10 October 1998. The Structures Panel of the Aeronautics Research and ...

  16. Structural Evolution of Three-Component Nanoparticles in Polymer Nanoreactors.

    Science.gov (United States)

    Chen, Peng-Cheng; Du, Jingshan S; Meckes, Brian; Huang, Liliang; Xie, Zhuang; Hedrick, James L; Dravid, Vinayak P; Mirkin, Chad A

    2017-07-26

    Recent developments in scanning probe block copolymer lithography (SPBCL) enable the confinement of multiple metal precursors in a polymer nanoreactor and their subsequent transformation into a single multimetallic heterostructured nanoparticle through thermal annealing. However, the process by which multimetallic nanoparticles form in SPBCL-patterned nanoreactors remains unclear. Here, we utilize the combination of PEO-b-P2VP and Au, Ag, and Cu salts as a model three-component system to investigate this process. The data suggest that the formation of single-component Au, Ag, or Cu nanoparticles within polymer nanoreactors consists of two stages: (I) nucleation, growth, and coarsening of the particles to yield a single particle in each reactor; (II) continued particle growth by depletion of the remaining precursor in the reactor until the particle reaches a stable size. Also, different aggregation rates are observed for single-component particle formation (Au > Ag > Cu). This behavior is also observed for two-component systems, where nucleation sites have greater Au content than the other metals. This information can be used to trap nanoparticles with kinetic structures. High-temperature treatment ultimately facilitates the structural evolution of the kinetic particle into a particle with a fixed structure. Therefore, with multicomponent systems, a third stage that involves elemental redistribution within the particle must be part of the description of the synthetic process. This work not only provides a glimpse at the mechanism underlying multicomponent nanoparticle formation in SPBCL-generated nanoreactors but also illustrates, for the first time, the utility of SPBCL as a platform for controlling the architectural evolution of multimetallic nanoparticles in general.

  17. Evolution of amino acid metabolism inferred through cladistic analysis.

    Science.gov (United States)

    Cunchillos, Chomin; Lecointre, Guillaume

    2003-11-28

    Because free amino acids were most probably available in primitive abiotic environments, their metabolism is likely to have provided some of the very first metabolic pathways of life. What were the first enzymatic reactions to emerge? A cladistic analysis of metabolic pathways of the 16 aliphatic amino acids and 2 portions of the Krebs cycle was performed using four criteria of homology. The analysis is not based on sequence comparisons but, rather, on coding similarities in enzyme properties. The properties used are shared specific enzymatic activity, shared enzymatic function without substrate specificity, shared coenzymes, and shared functional family. The tree shows that the earliest pathways to emerge are not portions of the Krebs cycle but metabolisms of aspartate, asparagine, glutamate, and glutamine. The views of Horowitz (Horowitz, N. H. (1945) Proc. Natl. Acad. Sci. U. S. A. 31, 153-157) and Cordón (Cordón, F. (1990) Tratado Evolucionista de Biologia, Aguilar, Madrid, Spain), according to which the upstream reactions in the catabolic pathways and the downstream reactions in the anabolic pathways are the earliest in evolution, are globally corroborated; however, with some exceptions. These are due to later opportunistic connections of pathways (actually already suggested by these authors). Earliest enzymatic functions are mostly catabolic; they were deaminations, transaminations, and decarboxylations. From the consensus tree we extracted four time spans for amino acid metabolism development. For some amino acids catabolism and biosynthesis occurred at the same time (Asp, Glu, Lys, Leu, Ala, Val, Ile, Pro, Arg). For others ultimate reactions that use amino acids as a substrate or as a product are distinct in time, with catabolism preceding anabolism for Asn, Gln, and Cys and anabolism preceding catabolism for Ser, Met, and Thr. Cladistic analysis of the structure of biochemical pathways makes hypotheses in biochemical evolution explicit and parsimonious.

  18. Rheological structure in Mars and its time evolution

    Science.gov (United States)

    Azuma, S.; Katayama, I.

    2014-12-01

    Mars is one of the terrestrial planets which are composed of rock and metal such as the Earth. There is no water, no life, and no plate tectonics on Mars, suggesting that Mars and Earth followed different evolutionary paths. Rheological structure, which indicates the deformation behavior and the strength of planetary interior, plays an important role in the evolution of planets. The rheological behavior of planetary interiors is strongly sensitive to temperature, which may produce strong rheological layering. Rheological structure of Mars in past must be different from the current rheological structure. First, the evolutions of temperature profiles in Mars are inferred from the surface heat flow and the heat conduction equation. The surface heat flow of Mars every 1 billion years was calculated from present abundances of the radioactive isotopes (235U, 235U, 232Th, and 40K) and their half-lives (Hahn et al 2011). Based on the temperature profile, we calculate the rheological structure of Mars every 1 billion years using flow-law of plagioclase and olivine. Calculated rheological structure shows that the brittle-ductile transition of present Mars, which is transition of deformation behavior from brittle failure to viscous flow, is deeper as compared with that of past Mars, suggesting that current elastic thickness also becomes thicker than that of past Mars. Under water-saturated conditions, the rheological structure which simulates the northern lowlands shows the strength contrast between the crust and mantle, indicating that the decoupling might occur at the Moho from 4 Ga to present day. Under dry conditions, lithosphere of northern lowlands has no strength contrast at the Moho, implying that crust and mantle might be coupled from 3 Ga to present day. Viscosity contrast between the surface and planetary interior is key for the mantle convection style (Moresi and Solomatov 1995), and the calculated viscosity contrast at present Mars is ~10-5 (Pa), suggesting that

  19. Convergent evolution of modularity in metabolic networks through different community structures

    Directory of Open Access Journals (Sweden)

    Zhou Wanding

    2012-09-01

    Full Text Available Abstract Background It has been reported that the modularity of metabolic networks of bacteria is closely related to the variability of their living habitats. However, given the dependency of the modularity score on the community structure, it remains unknown whether organisms achieve certain modularity via similar or different community structures. Results In this work, we studied the relationship between similarities in modularity scores and similarities in community structures of the metabolic networks of 1021 species. Both similarities are then compared against the genetic distances. We revisited the association between modularity and variability of the microbial living environments and extended the analysis to other aspects of their life style such as temperature and oxygen requirements. We also tested both topological and biological intuition of the community structures identified and investigated the extent of their conservation with respect to the taxomony. Conclusions We find that similar modularities are realized by different community structures. We find that such convergent evolution of modularity is closely associated with the number of (distinct enzymes in the organism’s metabolome, a consequence of different life styles of the species. We find that the order of modularity is the same as the order of the number of the enzymes under the classification based on the temperature preference but not on the oxygen requirement. Besides, inspection of modularity-based communities reveals that these communities are graph-theoretically meaningful yet not reflective of specific biological functions. From an evolutionary perspective, we find that the community structures are conserved only at the level of kingdoms. Our results call for more investigation into the interplay between evolution and modularity: how evolution shapes modularity, and how modularity affects evolution (mainly in terms of fitness and evolvability. Further, our results

  20. Non-Dissipative Structural Evolutions in Granular Materials

    Directory of Open Access Journals (Sweden)

    Pouragha Mehdi

    2017-01-01

    Full Text Available The structure of the contact network in granular assemblies can evolve due to either dissipative mechanisms such as sliding at contact points, or non-dissipative mechanisms through the phenomenon of contact gain and loss. Being associated with negligible deformations, non-dissipative mechanisms is actually active even in the small strain range of ~ 10−3, especially in the case of densely packed assemblies. Hence, from a constitutive modelling point of view, it is crucial to be able to estimate such non-dissipative evolutions since both elastic and plastic properties of granular assemblies highly depend on contact network characteristics. The current study proposes an analytical scheme that allows us to estimate the non-dissipative contact gain/loss regime in terms of directional changes in the average contact force. The probability distribution of contact forces is used to compute the number of lost contact for each direction. Similarly, the number of newly formed contacts is estimated by considering the probability distribution of the gap between neighbouring particles. Based on the directional contact gain/loss computed, the changes in coordination number and fabric anisotropy can be found which, together with statistical treatments of Love-Weber stress expression, form a complete system of equations describing the evolution of other controlling microvariables. Finally, the results of the calculations have been compared with DEM simulations which verify the accuracy of the proposed scheme.

  1. Structural evolution of a granular medium during simultaneous penetration

    Science.gov (United States)

    González-Gutiérrez, Jorge; Carreón, Yojana J. P.; Moctezuma, R. E.

    2018-01-01

    Typically, fluidized beds are granular systems composed of solid particles through which a fluid flows. They are relevant to a wide variety of disciplines such as physics, chemistry, engineering, among others. Generally, the fluidized beds are characterized by different flow regimes such as particulate, bubbling, slugging, turbulent, fast fluidization, and pneumatic conveying. Here, we report the experimental study of the structural evolution of a granular system due to simultaneous penetration of intruders in the presence of an upward airflow. We found that the granular medium evolves from the static state to the turbulent regime showing the coexistence of three regions in different flow regimes. Interestingly, the cooperative dynamic of intruders correlate with the formation of such regions. As a non-invasive method, we use lacunarity and fractal dimension to quantitatively describe the patterns arising within the system during the different stages of the penetration process. Finally, we found that our results would allow us to relate the evolution of the visual patterns appearing in the process with different physical properties of the system.

  2. Non-Dissipative Structural Evolutions in Granular Materials

    Science.gov (United States)

    Pouragha, Mehdi; Wan, Richard

    2017-06-01

    The structure of the contact network in granular assemblies can evolve due to either dissipative mechanisms such as sliding at contact points, or non-dissipative mechanisms through the phenomenon of contact gain and loss. Being associated with negligible deformations, non-dissipative mechanisms is actually active even in the small strain range of 10-3, especially in the case of densely packed assemblies. Hence, from a constitutive modelling point of view, it is crucial to be able to estimate such non-dissipative evolutions since both elastic and plastic properties of granular assemblies highly depend on contact network characteristics. The current study proposes an analytical scheme that allows us to estimate the non-dissipative contact gain/loss regime in terms of directional changes in the average contact force. The probability distribution of contact forces is used to compute the number of lost contact for each direction. Similarly, the number of newly formed contacts is estimated by considering the probability distribution of the gap between neighbouring particles. Based on the directional contact gain/loss computed, the changes in coordination number and fabric anisotropy can be found which, together with statistical treatments of Love-Weber stress expression, form a complete system of equations describing the evolution of other controlling microvariables. Finally, the results of the calculations have been compared with DEM simulations which verify the accuracy of the proposed scheme.

  3. Structures and their analysis

    CERN Document Server

    Fuchs, Maurice Bernard

    2016-01-01

    Addressing structures, this book presents a classic discipline in a modern setting by combining illustrated examples with insights into the solutions. It is the fruit of the author’s many years of teaching the subject and of just as many years of research into the design of optimal structures. Although intended for an advanced level of instruction it has an undergraduate course at its core. Further, the book was written with the advantage of having massive computer power in the background, an aspect which changes the entire approach to many engineering disciplines and in particular to structures. This paradigm shift has dislodged the force (flexibility) method from its former prominence and paved the way for the displacement (stiffness) method, despite the multitude of linear equations it spawns. In this book, however, both methods are taught: the force method offers a perfect vehicle for understanding structural behavior, bearing in mind that it is the displacement method which does the heavy number crunch...

  4. Media as the mechanism behind structural coupling and the evolution of the mind

    DEFF Research Database (Denmark)

    Tække, Jesper

    of the becoming of the psychic self. After this becoming other media of communication, as mechanisms behind the structural coupling, through the history of evolution has made a continuous increase of complexity, on both sides of the distinction between the psychic and the social, possible. This would be too much...... to elaborate for this paper, why it in its second part focuses on the psychic system. It tries to elaborate how, not only language, but also later media, through the history of evolution, generate the contemporary self. In doing that the paper describes five media revolutions (speech, writing, printing......, electronic media and digital media) and claims that each and one added medium extents the structural coupling, providing higher psychic reflexivity through the extended social complexity and vice versa. In this part the article also put forward an analysis of the different levels of self...

  5. Understanding the Global Structure and Evolution of Coronal Mass Ejections in the Solar Wind

    Science.gov (United States)

    Riley, Pete

    2004-01-01

    This report summarizes the technical progress made during the first six months of the second year of the NASA Living with a Star program contract Understanding the global structure and evolution of coronal mass ejections in the solar wind, between NASA and Science Applications International Corporation, and covers the period November 18, 2003 - May 17,2004. Under this contract SAIC has conducted numerical and data analysis related to fundamental issues concerning the origin, intrinsic properties, global structure, and evolution of coronal mass ejections in the solar wind. During this working period we have focused on a quantitative assessment of 5 flux rope fitting techniques. In the following sections we summarize the main aspects of this work and our proposed investigation plan for the next reporting period. Thus far, our investigation has resulted in 6 refereed scientific publications and we have presented the results at a number of scientific meetings and workshops.

  6. Transverse zones controlling the structural evolution of the Zipaquira Anticline (Eastern Cordillera, Colombia): Regional implications

    Science.gov (United States)

    García, Helbert; Jiménez, Giovanny

    2016-08-01

    We report paleomagnetic, magnetic fabric and structural results from 21 sites collected in Cretaceous marine mudstones and Paleogene continental sandstones from the limbs, hinge and transverse zones of the Zipaquira Anticline (ZA). The ZA is an asymmetrical fold with one limb completely overturned by processes like gravity and salt tectonics, and marked by several axis curvatures. The ZA is controlled by at least two (2) transverse zones known as the Neusa and Zipaquira Transverse Zones (NTZ and ZTZ, respectively). Magnetic mineralogy methods were applied at different sites and the main carriers of the magnetic properties are paramagnetic components with some sites being controlled by hematite and magnetite. Magnetic fabric analysis shows rigid-body rotation for the back-limb in the ZA, while the forelimb is subjected to internal deformation. Structural and paleomagnetic data shows the influence of the NTZ and ZTZ in the evolution of the different structures like the ZA and the Zipaquira, Carupa, Rio Guandoque, Las Margaritas and Neusa faults, controlling several factors as vergence, extension, fold axis curvature and stratigraphic detatchment. Clockwise rotations unraveled a block segmentation following a discontinuos model caused by transverse zones and one site reported a counter clockwise rotation associated with a left-lateral strike slip component for transverse faults (e.g. the Neusa Fault). We propose that diverse transverse zones have been active since Paleogene times, playing an important role in the tectonic evolution of the Cundinamarca sub-basin and controlling the structural evolution of folds and faults with block segmentation and rotations.

  7. Recapitulating the Structural Evolution of Redox Regulation in Adenosine 5'-Phosphosulfate Kinase from Cyanobacteria to Plants.

    Science.gov (United States)

    Herrmann, Jonathan; Nathin, David; Lee, Soon Goo; Sun, Tony; Jez, Joseph M

    2015-10-09

    In plants, adenosine 5'-phosphosulfate (APS) kinase (APSK) is required for reproductive viability and the production of 3'-phosphoadenosine 5'-phosphosulfate (PAPS) as a sulfur donor in specialized metabolism. Previous studies of the APSK from Arabidopsis thaliana (AtAPSK) identified a regulatory disulfide bond formed between the N-terminal domain (NTD) and a cysteine on the core scaffold. This thiol switch is unique to mosses, gymnosperms, and angiosperms. To understand the structural evolution of redox control of APSK, we investigated the redox-insensitive APSK from the cyanobacterium Synechocystis sp. PCC 6803 (SynAPSK). Crystallographic analysis of SynAPSK in complex with either APS and a non-hydrolyzable ATP analog or APS and sulfate revealed the overall structure of the enzyme, which lacks the NTD found in homologs from mosses and plants. A series of engineered SynAPSK variants reconstructed the structural evolution of the plant APSK. Biochemical analyses of SynAPSK, SynAPSK H23C mutant, SynAPSK fused to the AtAPSK NTD, and the fusion protein with the H23C mutation showed that the addition of the NTD and cysteines recapitulated thiol-based regulation. These results reveal the molecular basis for structural changes leading to the evolution of redox control of APSK in the green lineage from cyanobacteria to plants. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Biophysical and structural considerations for protein sequence evolution

    Directory of Open Access Journals (Sweden)

    Grahnen Johan A

    2011-12-01

    Full Text Available Abstract Background Protein sequence evolution is constrained by the biophysics of folding and function, causing interdependence between interacting sites in the sequence. However, current site-independent models of sequence evolutions do not take this into account. Recent attempts to integrate the influence of structure and biophysics into phylogenetic models via statistical/informational approaches have not resulted in expected improvements in model performance. This suggests that further innovations are needed for progress in this field. Results Here we develop a coarse-grained physics-based model of protein folding and binding function, and compare it to a popular informational model. We find that both models violate the assumption of the native sequence being close to a thermodynamic optimum, causing directional selection away from the native state. Sampling and simulation show that the physics-based model is more specific for fold-defining interactions that vary less among residue type. The informational model diffuses further in sequence space with fewer barriers and tends to provide less support for an invariant sites model, although amino acid substitutions are generally conservative. Both approaches produce sequences with natural features like dN/dS Conclusions Simple coarse-grained models of protein folding can describe some natural features of evolving proteins but are currently not accurate enough to use in evolutionary inference. This is partly due to improper packing of the hydrophobic core. We suggest possible improvements on the representation of structure, folding energy, and binding function, as regards both native and non-native conformations, and describe a large number of possible applications for such a model.

  9. The Structure and Evolution of Cold Dark Matter Halos

    Science.gov (United States)

    Diemand, Jürg; Moore, Ben

    2011-02-01

    In the standard cosmological model a mysterious cold dark matter (CDM) component dominates the formation of structures. Numerical studies of the f ormation of CDM halos have produced several robust results that allow unique tests of the hierarchical clustering paradigm. Universal properties of halos, including their mass profiles and substructure properties are roughly consistent with observational data from the scales of dwarf galaxies to galaxy clusters. Resolving the fine grained structure of halos has enabled us to make predictions for ongoing and planned direct and indirect dark matter detection experiments. While simulations of pure CDM halos are now very accurate and in good agreement (recently claimed discrepancies are addressed in detail in this review), we are still unable to make robust, quantitative predictions about galaxy formation and about how the dark matter distribution changes in the process. Whilst discrepancies between observations and simulations have been the subject of much debate in the literature, galaxy formation and evolution needs to be understood in more detail in order to fully test the CDM paradigm. Whatever the true nature of the dark matter particle is, its clustering properties must not be too different from a cold neutralino like particle to maintain all the successes of the model in matching large scale structure data and the global properties of halos which are mostly in good agreement with observations.

  10. Structural evolution, growth and stability of metal titanium clusters

    Science.gov (United States)

    Chauke, Hasani; Phaahla, Tshegofatso; Ngoepe, Phuti; Catlow, Richard

    The transition metals clusters such as titanium have received a significant attention due to their excellent physical and chemical properties and great technological application in many fields. A survey of small Ti clusters was performed using interatomic potentials and computational methods based on density functional theory; and the knowledge led master code with a genetic algorithm to generate the lowest energy geometries of Tin (n = 2-32) clusters. The all electron spin-unpolarized generalized gradient approximation is used to determine the ground state structures, binding energy and electronic properties. The structural evolution of titanium clusters, which favors the icosahedron structure growth pattern is observed. The energy for the ground state configurations is found to increase monotonically with the clusters size. Their relative stability results predict clusters with 5 and 7 as more stable. The energy difference for clusters n >=24 is very small, suggesting that the larger clusters could be stable at moderate temperatures. In addition to the magic numbers that are often reported i.e. Ti7 and Ti13; clusters 5, 9, 14, 17 and 26 have extra stability.

  11. Coherent structures and turbulence evolution in magnetized non-neutral plasmas

    Science.gov (United States)

    Romé, M.; Chen, S.; Maero, G.

    2018-01-01

    The evolution of turbulence of a magnetized pure electron plasma confined in a Penning-Malmberg trap is investigated by means of a two-dimensional particle-in-cell numerical code. The transverse plasma dynamics is studied both in the case of free evolution and under the influence of non-axisymmetric, multipolar radio-frequency drives applied on the circular conducting boundary. In the latter case the radio-frequency fields are chosen in the frequency range of the low-order azimuthal (diocotron) modes of the plasma in order to investigate their effect on the insurgence of azimuthal instabilities and the formation and evolution of coherent structures, possibly preventing the relaxation to a fully-developed turbulent state. Different initial density distributions (rings and spirals) are considered, so that evolutions characterized by different levels of turbulence and intermittency are obtained. The time evolution of integral and spectral quantities of interest are computed using a multiresolution analysis based on a wavelet decomposition of density maps. Qualitative features of turbulent relaxation are found to be similar in conditions of both free and forced evolution, but the analysis allows one to highlight fine details of the flow beyond the self-similarity turbulence properties, so that the influence of the initial conditions and the effect of the external forcing can be distinguished. In particular, the presence of small inhomogeneities in the initial density configuration turns out to lead to quite different final states, especially in the presence of competing unstable diocotron modes characterized by similar growth rates.

  12. Collapse Analysis of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2008-01-01

    to criteria a) and b) the timber frame structure has one column with a reliability index a bit lower than an assumed target level. By removal three columns one by one no significant extensive failure of the entire structure or significant parts of it are obtained. Therefore the structure can be considered......A probabilistic based collapse analysis has been performed for a glulam frame structure supporting the roof over the main court in a Norwegian sports centre. The robustness analysis is based on the framework for robustness analysis introduced in the Danish Code of Practice for the Safety...... of Structures and a probabilistic modelling of the timber material proposed in the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS). Due to the framework in the Danish Code the timber structure has to be evaluated with respect to the following criteria where at least one shall...

  13. Nonlinear Structural Analysis

    Indian Academy of Sciences (India)

    at the Indian Institute of Technology Madras, Chennai, on 9±10 October 1998. The Structures Panel of the ... have pushed frontiers of technology to such extents that linear theories no longer suffice. This is the case in ... In the second paper, Krishnam Raju and Nagabhushanam extend the Integrated Force. Method (IFM) of ...

  14. Structural systems reliability analysis

    International Nuclear Information System (INIS)

    Frangopol, D.

    1975-01-01

    For an exact evaluation of the reliability of a structure it appears necessary to determine the distribution densities of the loads and resistances and to calculate the correlation coefficients between loads and between resistances. These statistical characteristics can be obtained only on the basis of a long activity period. In case that such studies are missing the statistical properties formulated here give upper and lower bounds of the reliability. (orig./HP) [de

  15. Structure and Evolution of Kuiper Belt Objects and Dwarf Planets

    Science.gov (United States)

    McKinnon, W. B.; Prialnik, D.; Stern, S. A.; Coradini, A.

    Kuiper belt objects (KBOs) accreted from a mélange of volatile ices, carbonaceous matter, and rock of mixed interstellar and solar nebular provenance. The transneptunian region, where this accretion took place, was likely more radially compact than today. This and the influence of gas drag during the solar nebula epoch argue for more rapid KBO accretion than usually considered. Early evolution of KBOs was largely the result of heating due to radioactive decay, the most important potential source being 26Al, whereas long-term evolution of large bodies is controlled by the decay of U, Th, and 40K. Several studies are reviewed dealing with the evolution of KBO models, calculated by means of one-dimensional numerical codes that solve the heat and mass balance equations. It is shown that, depending on parameters (principally rock content and porous conductivity), KBO interiors may have reached relatively high temperatures. The models suggest that KBOs likely lost ices of very volatile species during early evolution, whereas ices of less-volatile species should be retained in cold, less-altered subsurface layers. Initially amorphous ice may have crystallized in KBO interiors, releasing volatiles trapped in the amorphous ice, and some objects may have lost part of these volatiles as well. Generally, the outer layers are far less affected by internal evolution than the inner part, which in the absence of other effects (such as collisions) predicts a stratified composition and altered porosity distribution. Kuiper belt objects are thus unlikely to be "the most pristine objects in the solar system," but they do contain key information as to how the early solar system accreted and dynamically evolved. For large (dwarf planet) KBOs, long-term radiogenic heating alone may lead to differentiated structures -- rock cores, ice mantles, volatile-ice-rich "crusts," and even oceans. Persistence of oceans and (potential) volcanism to the present day depends strongly on body size and

  16. Social structure, opportunistic punishment and the evolution of honest signaling

    Science.gov (United States)

    2017-01-01

    Honest signaling is generally taken to be a necessary pre-condition for a stable signaling system, because deceptive signaling at a high enough rate should cause receivers to ignore the signal, which in turn undermines the utility of sending signals. Deception is normally thought to occur because of benefits it has to the deceiver. This raises the question of why signaling systems should exist and persist over time, especially in cases in which the interests of the senders and receivers are not well aligned. Punishment has been seen as a way of imposing costs on deceptive signalers. We investigate the effects of opportunistic—that is, non-altruistic punishment—on the evolution of an honest signaling system. Our model is based on research done on social insects. We model a society of agents, divided into three castes differing in aggressiveness. Under severe punishment deception is indeed asymptotically eliminated. Under somewhat less severe punishment, deception persists and the rates of deception correlate with social structure. We find that social structure robustly mediates the level of deception under regimes of punishment and that this is evident except in the most stringent of punishment regimes. PMID:29220400

  17. Structures in the Universe by Exact Methods: Formation, Evolution, Interactions

    Science.gov (United States)

    Bolejko, Krzysztof; Krasiński, Andrzej; Hellaby, Charles; Célérier, Marie-Noëlle

    2009-10-01

    As the structures in our Universe are mapped out on ever larger scales, and with increasing detail, the use of inhomogeneous models is becoming an essential tool for analyzing and understanding them. This book reviews a number of important developments in the application of inhomogeneous solutions of Einstein's field equations to cosmology. It shows how inhomogeneous models can be employed to study the evolution of structures such as galaxy clusters and galaxies with central black holes, and to account for cosmological observations like supernovae dimming, the cosmic microwave background, baryon acoustic oscillations or the dependence of the Hubble parameter on redshift within classical general relativity. Whatever 'dark matter' and 'dark energy' turn out to be, inhomogeneities exist on many scales and need to be investigated with all appropriate methods. This book is of great value to all astrophysicists and researchers working in cosmology, from graduate students to academic researchers. - Presents inhomogeneous cosmological models, allowing readers to familiarise themselves with basic properties of these models - Shows how inhomogeneous models can be used to analyse cosmological observations such as supernovae, cosmic microwave background, and baryon acoustic oscillations - Reviews important developments in the application of inhomogeneous solutions of Einstein's field equations to cosmology

  18. Orchestrated structure evolution: modeling growth-regulated nanomanufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi, Shaghayegh; Boehringer, Karl F [Department of Electrical Engineering, University of Washington, Seattle, WA 98195-2500 (United States); Kitayaporn, Sathana; Schwartz, Daniel T, E-mail: karlb@washington.edu [Department of Chemical Engineering, University of Washington, Seattle, WA 98195-2500 (United States)

    2011-04-22

    Orchestrated structure evolution (OSE) is a scalable manufacturing method that combines the advantages of top-down (tool-directed) and bottom-up (self-propagating) approaches. The method consists of a seed patterning step that defines where material nucleates, followed by a growth step that merges seeded islands into the final patterned thin film. We develop a model to predict the completed pattern based on a computationally efficient approximate Green's function solution of the diffusion equation plus a Voronoi diagram based approach that defines the final grain boundary structure. Experimental results rely on electron beam lithography to pattern the seeds, followed by the mass transfer limited growth of copper via electrodeposition. The seed growth model is compared with experimental results to quantify nearest neighbor seed-to-seed interactions as well as how seeds interact with the pattern boundary to impact the local growth rate. Seed-to-seed and seed-to-pattern interactions are shown to result in overgrowth of seeds on edges and corners of the shape, where seeds have fewer neighbors. We explore how local changes to the seed location can be used to improve the patterning quality without increasing the manufacturing cost. OSE is shown to enable a unique set of trade-offs between the cost, time, and quality of thin film patterning.

  19. Evolution and Structural Analyses of Glossina morsitans (Diptera; Glossinidae Tetraspanins

    Directory of Open Access Journals (Sweden)

    Edwin K. Murungi

    2014-11-01

    Full Text Available Tetraspanins are important conserved integral membrane proteins expressed in many organisms. Although there is limited knowledge about the full repertoire, evolution and structural characteristics of individual members in various organisms, data obtained so far show that tetraspanins play major roles in membrane biology, visual processing, memory, olfactory signal processing, and mechanosensory antennal inputs. Thus, these proteins are potential targets for control of insect pests. Here, we report that the genome of the tsetse fly, Glossina morsitans (Diptera: Glossinidae encodes at least seventeen tetraspanins (GmTsps, all containing the signature features found in the tetraspanin superfamily members. Whereas six of the GmTsps have been previously reported, eleven could be classified as novel because their amino acid sequences do not map to characterized tetraspanins in the available protein data bases. We present a model of the GmTsps by using GmTsp42Ed, whose presence and expression has been recently detected by transcriptomics and proteomics analyses of G. morsitans. Phylogenetically, the identified GmTsps segregate into three major clusters. Structurally, the GmTsps are largely similar to vertebrate tetraspanins. In view of the exploitation of tetraspanins by organisms for survival, these proteins could be targeted using specific antibodies, recombinant large extracellular loop (LEL domains, small-molecule mimetics and siRNAs as potential novel and efficacious putative targets to combat African trypanosomiasis by killing the tsetse fly vector.

  20. Collapse Analysis of Timber Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2008-01-01

    A probabilistic based collapse analysis has been performed for a glulam frame structure supporting the roof over the main court in a Norwegian sports centre. The robustness analysis is based on the framework for robustness analysis introduced in the Danish Code of Practice for the Safety...... be fulfilled: a) demonstrating that those parts of the structure essential for the safety only have little sensitivity with respect to unintentional loads and defects, or b) demonstrating a load case with „removal of a limited part of the structure‟ in order to document that an extensive failure...... of the structure will not occur if a limited part of the structure fails, or c) demonstrating sufficient safety of key elements, such that the entire structure with one or more key elements has the same reliability as a structure where robustness is documented by b). Based on investigations with respect...

  1. Lithosphere structure and subsidence evolution of the conjugate S-African and Argentine margins

    Science.gov (United States)

    Dressel, Ingo; Scheck-Wenderoth, Magdalena; Cacace, Mauro; Götze, Hans-Jürgen; Franke, Dieter

    2016-04-01

    The bathymetric evolution of the South Atlantic passive continental margins is a matter of debate. Though it is commonly accepted that passive margins experience thermal subsidence as a result of lithospheric cooling as well as load induced subsidence in response to sediment deposition it is disputed if the South Atlantic passive margins were affected by additional processes affecting the subsidence history after continental breakup. We present a subsidence analysis along the SW African margin and offshore Argentina and restore paleobathymetries to assess the subsidence evolution of the margin. These results are discussed with respect to mechanisms behind margin evolution. Therefore, we use available information about the lithosphere-scale present-day structural configuration of these margins as a starting point for the subsidence analysis. A multi 1D backward modelling method is applied to separate individual subsidence components such as the thermal- as well as the load induced subsidence and to restore paleobathymetries for the conjugate margins. The comparison of the restored paleobathymetries shows that the conjugate margins evolve differently: Continuous subsidence is obtained offshore Argentina whereas the subsidence history of the SW African margin is interrupted by phases of uplift. This differing results for both margins correlate also with different structural configurations of the subcrustal mantle. In the light of these results we discuss possible implications for uplift mechanisms.

  2. Markov chains or the game of structure and chance. From complex networks, to language evolution, to musical compositions

    Science.gov (United States)

    Blanchard, Ph.; Dawin, J. R.; Volchenkov, D.

    2010-06-01

    Markov chains provide us with a powerful tool for studying the structure of graphs and databases in details. We review the method of generalized inverses for Markov chains and apply it for the analysis of urban structures, evolution of languages, and musical compositions. We also discuss a generalization of Lévy flights over large complex networks and study the interplay between the nonlinearity of diffusion process and the topological structure of the network.

  3. Structural motifs of syringyl peroxidases are conserved during angiosperm evolution.

    Science.gov (United States)

    Gómez Ros, Laura V; Aznar-Asensio, Ginés J; Hernandez, Jose A; Bernal, Maria A; Núñez-Flores, María J L; Cuello, Juan; Ros Barceló, Alfonso

    2007-05-16

    The most distinctive variation in the monomer composition of lignins in vascular land plants is that between the two main groups of seed plants. Thus, whereas gymnosperm (softwood) lignins are typically composed of guaiacyl (G) units, angiosperm (hardwood) lignins are largely composed of similar levels of G and syringyl (S) units. However, there are some studies that suggest that certain angiosperm peroxidases are unable to oxidize sinapyl alcohol, and a coniferyl alcohol shuttle has been proposed for oxidizing S units during the biosynthesis of lignins. With this in mind, a screening of the presence of S peroxidases in angiosperms (including woody species and forages) was performed. Contrarily to what might be expected, the intercellular washing fluids from lignifying tissues of 25 woody, herbaceous, and shrub species, belonging to both monocots and dicotyledons, all showed both S peroxidase activities and basic peroxidase isoenzymes analogous, with regard the isoelectric point, to the Zinnia elegans basic peroxidase isoenzyme, the only S peroxidase that has been fully characterized. These results led to the protein database in the search for homologies between angiosperm peroxidases and a true eudicot S peroxidase, the Z. elegans peroxidase. The findings showed that certain structural motifs of S peroxidases are conserved within the first 15 million years of angiosperm history, because they are found in peroxidases from the two major lineages of flowering plants, eumagnoliids and eudicotyledons, of note being the presence of these peroxidases in Amborella and Nymphaeales, which represent the first stages of angiosperm evolution. These phylogenetic studies also suggest that guaiacyl peroxidases apparently constitute the most "evolved state" of the plant peroxidase family evolution.

  4. Studies of the structure and evolution of the intracluster medium

    Science.gov (United States)

    O'Hara, Timothy Brian

    The intracluster medium (ICM) in galaxy clusters is influenced by multiple processes, such as mergers and radiative cooling. In this dissertation we examine how these processes affect the structure and formation history of the ICM via both detailed individual cluster study and by study of bulk properties in large cluster data sets. This work provides important constraints on the evolution of the ICM, and in particular on the effects of mergers and cool core formation on ICM structure. We use high-resolution X-ray data to identify merger features in the cluster A2319, and propose a dynamical model for the merger. Remarkably, the bulk properties of this merging cluster are not significantly perturbed relative to the values predicted by scaling relations. This question of merger effects on bulk properties is pursued further in a study of 45 nearby clusters. We show that cool core-related phenomena, and not mergers, are the primary source of scatter in scaling relations among bulk properties. This surprising result, with greater scatter in the cool core population than in non-cool core clusters, may support cluster formation scenarios in which the presence of a cool core is primarily determined by factors beyond simply the time since the last major merger. We show that the central X-ray surface brightness can be used to significantly decrease the scatter in sealing relations by acting as a proxy for cool core "strength", a finding beneficial for duster cosmology surveys that use X-ray luminosity as a proxy for mass. Finally, we examine how scaling relations evolve with redshift using a 70 cluster sample over the redshift range 0.18 cluster formation. Effects of core structure are again apparent in this work, as scaling relations constructed from core subtracted quantities evolve differently from those using non-core subtracted quantities, and the scatter in scaling relations and in central surface brightness increases at low redshift.

  5. Modeling of creep for structural analysis

    Energy Technology Data Exchange (ETDEWEB)

    Naumenko, K.; Altenbach, H. [Halle-Wittenberg Univ., Halle (Germany). Lehrstuhl fuer Technische Mechanik

    2007-07-01

    ''Creep Modeling for Structural Analysis'' develops methods to simulate and analyze the time-dependent changes of stress and strain states in engineering structures up to the critical stage of creep rupture. The principal subjects of creep mechanics are the formulation of constitutive equations for creep in structural materials under multi-axial stress states; the application of structural mechanics models of beams, plates, shells and three-dimensional solids and the utilization of procedures for the solution of non-linear initial-boundary value problems. The objective of this book is to review some of the classical and recently proposed approaches to the modeling of creep for structural analysis applications as well as to extend the collection of available solutions of creep problems by new, more sophisticated examples. In Chapter 1, the book discusses basic features of the creep behavior in materials and structures and presents an overview of various approaches to the modeling of creep. Chapter 2 collects constitutive models that describe creep and damage processes under multi-axial stress states. Chapter 3 deals with the application of constitutive models to the description of creep for several structural materials. Constitutive and evolution equations, response functions and material constants are presented according to recently published experimental data. In Chapter 4 the authors discuss structural mechanics problems. Governing equations of creep in three-dimensional solids, direct variational methods and time step algorithms are reviewed. Examples are presented to illustrate the application of advanced numerical methods to the structural analysis. An emphasis is placed on the development and verification of creep-damage material subroutines inside the general purpose finite element codes. (orig.)

  6. Dislocation structure evolution and characterization in the compression deformed Mn-Cu alloy

    International Nuclear Information System (INIS)

    Zhong, Y.; Yin, F.; Sakaguchi, T.; Nagai, K.; Yang, K.

    2007-01-01

    Dislocation densities and dislocation structure arrangements in cold compressed polycrystalline commercial M2052 (Mn-20Cu-5Ni-2Fe) high damping alloy with various strains were determined in scanning mode by X-ray peak profile analysis and electron backscatter diffraction (EBSD). The results indicate that the Mn-Cu-Ni-Fe alloy has an evolution behavior quite similar to the dislocation structure in copper. The dislocation arrangement parameter shows a local minimum in the transition range between stages III and IV that can be related to the transformation of the dislocation arrangement in the cell walls from a polarized dipole wall (PDW) into a polarized tile wall (PTW) structure. This evolution is further confirmed by the results of local misorientation determined by EBSD. In addition, during deformation, the multiplication of dislocation densities in the MnCu alloy is significantly slower than that in copper, and the transition of the dislocation structure is strongly retarded in the MnCu alloy compared with copper. These results can be explained by the mechanism of elastic anisotropy on the dislocation dynamics, as the elastic anisotropy in the MnCu alloy is larger than that in copper, which can strongly retard the multiplication of the dislocation population and the transformation of the dislocation structure. These results are important for research into the plastic working behavior of Mn-Cu-Ni-Fe high damping alloy

  7. Computational Analysis for Morphological Evolution in Pyrolysis for Micro/Nanofabrication

    OpenAIRE

    Yang, Myeongseok; Lee, Wooju; Shin, Heungjoo; Kim, Dongchoul

    2015-01-01

    Pyrolysis is recently proposed as an efficient fabrication technique of micro/nanoscale carbon structures. In order to understand the morphological evolution in pyrolysis and design the final shape of carbon structure, this study proposes a comprehensive model that incorporates the essential mechanisms of pyrolysis based on the phase field framework. Computational analysis with the developed model provides information about the effect of interface energy and kinetic rate on the morphological ...

  8. Coda Wave Interferometry Method Applied in Structural Monitoring to Assess Damage Evolution in Masonry and Concrete Structures

    International Nuclear Information System (INIS)

    Masera, D; Bocca, P; Grazzini, A

    2011-01-01

    In this experimental program the main goal is to monitor the damage evolution in masonry and concrete structures by Acoustic Emission (AE) signal analysis applying a well-know seismic method. For this reason the concept of the coda wave interferometry is applied to AE signal recorded during the tests. Acoustic Emission (AE) are very effective non-destructive techniques applied to identify micro and macro-defects and their temporal evolution in several materials. This technique permits to estimate the velocity of ultrasound waves propagation and the amount of energy released during fracture propagation to obtain information on the criticality of the ongoing process. By means of AE monitoring, an experimental analysis on a set of reinforced masonry walls under variable amplitude loading and strengthening reinforced concrete (RC) beams under monotonic static load has been carried out. In the reinforced masonry wall, cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of masonry under static long-time loading. During the tests, the evaluation of fracture growth is monitored by coda wave interferometry which represents a novel approach in structural monitoring based on AE relative change velocity of coda signal. In general, the sensitivity of coda waves has been used to estimate velocity changes in fault zones, in volcanoes, in a mining environment, and in ultrasound experiments. This method uses multiple scattered waves, which travelled through the material along numerous paths, to infer tiny temporal changes in the wave velocity. The applied method has the potential to be used as a 'damage-gauge' for monitoring velocity changes as a sign of damage evolution into masonry and concrete structures.

  9. Evolution of vortex structures in an electromagnetically excited separated flow

    Energy Technology Data Exchange (ETDEWEB)

    Cierpka, Christian; Weier, Tom; Gerbeth, Gunter [Forschungszentrum Dresden-Rossendorf, Dresden (Germany)

    2008-11-15

    Time periodic wall parallel Lorentz forces have been used to excite the separated flow on the suction side of an inclined flat plate. Experiments for a Reynolds number of 10{sup 4} and an angle of attack of {alpha}=13 are reported. The controlled flow is characterised by a small number of relatively large scale vortices, which are related to the control mechanism. The influence of the main parameters, i.e. the excitation frequency, amplitude and wave form on the suction side flow structures was investigated by analysing time resolved particle image velocimetry (TR-PIV) measurements using continuous wavelet analysis for vortex detection and characterisation. Statistical analysis of the coherent structures of the flow was performed on a large amount of data samples. (orig.)

  10. Evolution of the macromolecular structure of sporopollenin during thermal degradation.

    Science.gov (United States)

    Bernard, S; Benzerara, K; Beyssac, O; Balan, E; Brown, G E

    2015-10-01

    Reconstructing the original biogeochemistry of organic microfossils requires quantifying the extent of the chemical transformations they experienced during burial and maturation processes. In the present study, fossilization experiments have been performed using modern sporopollenin chosen as an analogue for the resistant biocompounds possibly constituting the wall of many organic microfossils. Sporopollenin powder has been processed thermally under argon atmosphere at different temperatures (up to 1000 °C) for varying durations (up to 900 min). Solid residues of each experiment have been characterized using infrared, Raman and synchrotron-based XANES spectroscopies. Results indicate that significant defunctionalisation and aromatization affect the molecular structure of sporopollenin with increasing temperature. Two distinct stages of evolution with temperature are observed: in a first stage, sporopollenin experiences dehydrogenation and deoxygenation simultaneously (below 500 °C); in a second stage (above 500 °C) an increasing concentration in aromatic groups and a lateral growth of aromatic layers are observed. With increasing heating duration (up to 900 min) at a constant temperature (360 °C), oxygen is progressively lost and conjugated carbon-carbon chains or domains grow progressively, following a log-linear kinetic behavior. Based on the comparison with natural spores fossilized within metasediments which experienced intense metamorphism, we show that the present experimental simulations may not perfectly mimic natural diagenesis and metamorphism. Yet, performing such laboratory experiments provides key insights on the processes transforming biogenic molecules into molecular fossils.

  11. Evolution of the macromolecular structure of sporopollenin during thermal degradation

    Directory of Open Access Journals (Sweden)

    S. Bernard

    2015-10-01

    Full Text Available Reconstructing the original biogeochemistry of organic microfossils requires quantifying the extent of the chemical transformations they experienced during burial and maturation processes. In the present study, fossilization experiments have been performed using modern sporopollenin chosen as an analogue for the resistant biocompounds possibly constituting the wall of many organic microfossils. Sporopollenin powder has been processed thermally under argon atmosphere at different temperatures (up to 1000 °C for varying durations (up to 900 min. Solid residues of each experiment have been characterized using infrared, Raman and synchrotron-based XANES spectroscopies. Results indicate that significant defunctionalisation and aromatization affect the molecular structure of sporopollenin with increasing temperature. Two distinct stages of evolution with temperature are observed: in a first stage, sporopollenin experiences dehydrogenation and deoxygenation simultaneously (below 500 °C; in a second stage (above 500 °C an increasing concentration in aromatic groups and a lateral growth of aromatic layers are observed. With increasing heating duration (up to 900 min at a constant temperature (360 °C, oxygen is progressively lost and conjugated carbon–carbon chains or domains grow progressively, following a log-linear kinetic behavior. Based on the comparison with natural spores fossilized within metasediments which experienced intense metamorphism, we show that the present experimental simulations may not perfectly mimic natural diagenesis and metamorphism. Yet, performing such laboratory experiments provides key insights on the processes transforming biogenic molecules into molecular fossils.

  12. The structure and evolution of buyer-supplier networks.

    Science.gov (United States)

    Mizuno, Takayuki; Souma, Wataru; Watanabe, Tsutomu

    2014-01-01

    In this paper, we investigate the structure and evolution of customer-supplier networks in Japan using a unique dataset that contains information on customer and supplier linkages for more than 500,000 incorporated non-financial firms for the five years from 2008 to 2012. We find, first, that the number of customer links is unequal across firms; the customer link distribution has a power-law tail with an exponent of unity (i.e., it follows Zipf's law). We interpret this as implying that competition among firms to acquire new customers yields winners with a large number of customers, as well as losers with fewer customers. We also show that the shortest path length for any pair of firms is, on average, 4.3 links. Second, we find that link switching is relatively rare. Our estimates indicate that the survival rate per year for customer links is 92 percent and for supplier links 93 percent. Third and finally, we find that firm growth rates tend to be more highly correlated the closer two firms are to each other in a customer-supplier network (i.e., the smaller is the shortest path length for the two firms). This suggests that a non-negligible portion of fluctuations in firm growth stems from the propagation of microeconomic shocks - shocks affecting only a particular firm - through customer-supplier chains.

  13. Structural evolution and mechanisms of fatigue in polycrystalline brass

    International Nuclear Information System (INIS)

    Vejloe Carstensen, J.

    1998-03-01

    The plastic strain controlled fatigue behaviour of polycrystalline Cu-15%Zn and Cu-30%Zn has been investigated with the aim of studying the effect of slip mode modification by the addition of zinc to copper. It has been clearly demonstrated, that true cyclic saturation does not occur in the plastic strain controlled fatigue of brass. This complicates the contstruction of a cyclic stress-strain (CSS) curve and thus the comparison with copper. A method to overcome this complication has been suggested. Surface observations on fatigued brass specimens show that individual grains tend to deform by Sachs type single slip. This behaviour has been described by the self-consistent Sachs-Eshelby model, which provides estimates of the CSS curve for brass polycrystals. Successive stages of primary hardening, softening and secondary hardening has been observed in the plastic strain controlled fatigue of brass. It has been found that the primary hardening is attributed to an increase of intergranular stresses whereas the secondary hardening apparently is attributed to an increase of friction stresses. Investigations of the structural evolution show that the softening behaviour can be explained by the presence of short-range order (SRO). SRO promote the formation of extended dipole arrays which hardens the material. The formation of intense shear bands destroy the dipole arrays, which explains the cyclic softening. The present results reveal that Cu-30%Zn in a pure planar slip alloy, while Cu-15%Zn displays both planar and wavy slip. The mechanical and structural behaviour observed in brass resembles recent observations in 316L austenitic stainless steels, and the present results reveal that Cu-30%Zn and 316L have approximately the same fatigue life curve. This emphasizes brass as being a convenient model system for the industrially important austenitic steels. (au)

  14. Structural evolution and mechanisms of fatigue in polycrystalline brass

    Energy Technology Data Exchange (ETDEWEB)

    Vejloe Carstensen, J

    1998-03-01

    The plastic strain controlled fatigue behaviour of polycrystalline Cu-15%Zn and Cu-30%Zn has been investigated with the aim of studying the effect of slip mode modification by the addition of zinc to copper. It has been clearly demonstrated, that true cyclic saturation does not occur in the plastic strain controlled fatigue of brass. This complicates the contstruction of a cyclic stress-strain (CSS) curve and thus the comparison with copper. A method to overcome this complication has been suggested. Surface observations on fatigued brass specimens show that individual grains tend to deform by Sachs type single slip. This behaviour has been described by the self-consistent Sachs-Eshelby model, which provides estimates of the CSS curve for brass polycrystals. Successive stages of primary hardening, softening and secondary hardening has been observed in the plastic strain controlled fatigue of brass. It has been found that the primary hardening is attributed to an increase of intergranular stresses whereas the secondary hardening apparently is attributed to an increase of friction stresses. Investigations of the structural evolution show that the softening behaviour can be explained by the presence of short-range order (SRO). SRO promote the formation of extended dipole arrays which hardens the material. The formation of intense shear bands destroy the dipole arrays, which explains the cyclic softening. The present results reveal that Cu-30%Zn in a pure planar slip alloy, while Cu-15%Zn displays both planar and wavy slip. The mechanical and structural behaviour observed in brass resembles recent observations in 316L austenitic stainless steels, and the present results reveal that Cu-30%Zn and 316L have approximately the same fatigue life curve. This emphasizes brass as being a convenient model system for the industrially important austenitic steels. (au) 9 tabs., 94 ills., 177 refs.; The thesis is also available as DCAMM-R-S80 and as an electronic document on http://www.risoe.dk/rispubl

  15. Structure, functions, and evolution of the third complement component and viral molecular mimicry.

    Science.gov (United States)

    Sahu, A; Sunyer, J O; Moore, W T; Sarrias, M R; Soulika, A M; Lambris, J D

    1998-01-01

    The third component of the complement system, C3, is a common denominator in the activation of the classical, alternative, and lectin pathways. The ability of C3 molecule to interact with at least 20 different proteins makes it the most versatile component of this system. Since these interactions are important for phagocytic, immunoregulatory, and immune evasion mechanisms, the analysis of its structure and functions has been a subject of intense research. Here we review our current work on the C3-ligand interactions, C3-related viral molecular mimicry, evolution of the complement system, and identification of C3-based complement inhibitors.

  16. Symbiosis Enables the Evolution of Rare Complexes in Structured Environments

    OpenAIRE

    Mills, Rob; Watson, Richard A.

    2009-01-01

    We present a model that considers evolvable symbiotic associations between species, such that one species can have an influence over the likelihood of other species being present in its environment. We show that this process of 'symbiotic evolution' leads to rare and adaptively significant complexes that are unavailable via non-associative evolution.

  17. Structural evolution of Ni-20Cr alloy during ball milling of elemental powders

    International Nuclear Information System (INIS)

    Lopez B, I.; Trapaga M, L. G.; Martinez F, E.; Zoz, H.

    2011-01-01

    The ball milling (B M) of blended Ni and Cr elemental powders was carried out in a Simoloyer performing on high-energy scale mode at maximum production to obtain a nano structured Ni-20Cr alloy. The phase transformations and structural changes occurring during mechanical alloying were investigated by X-ray diffraction (XRD) and optical microscopy (Om). A gradual solid solubility of Cr and the subsequent formation of crystalline metastable solid solutions described in terms of the Avrami-Ero fe ev kinetics model were calculated. The XRD analysis of the structure indicates that cumulative lattice strain contributes to the driving force for solid solution between Ni and Cr during B M. Microstructure evolution has shown, additionally to the lamellar length refinement commonly observed, the folding of lamellae in the final processing stage. Om observations revealed that the lamellar spacing of Ni rich zones reaches a steady value near 500 nm and almost disappears after 30 h of milling. (Author)

  18. Evolution of Fungal U3 snoRNAs: Structural Variation and Introns

    Directory of Open Access Journals (Sweden)

    Sebastian Canzler

    2017-01-01

    Full Text Available The U3 small nucleolar RNA (snoRNA is an essential player in the initial steps of ribosomal RNA biogenesis which is ubiquitously present in Eukarya. It is exceptional among the small nucleolar RNAs in its size, the presence of multiple conserved sequence boxes, a highly conserved secondary structure core, its biogenesis as an independent gene transcribed by polymerase III, and its involvement in pre-rRNA cleavage rather than chemical modification. Fungal U3 snoRNAs share many features with their sisters from other eukaryotic kingdoms but differ from them in particular in their 5’ regions, which in fungi has a distinctive consensus structure and often harbours introns. Here we report on a comprehensive homology search and detailed analysis of the evolution of sequence and secondary structure features covering the entire kingdom Fungi.

  19. Structural evolution of Ni-20Cr alloy during ball milling of elemental powders

    Energy Technology Data Exchange (ETDEWEB)

    Lopez B, I.; Trapaga M, L. G. [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Juriquilla, 76230 Queretaro (Mexico); Martinez F, E. [Centro de Investigacion e Innovacion Tecnologica, Cerrada de Cecati s/n, Col. Santa Catarina Azcapotzalco, 02250 Mexico D. F. (Mexico); Zoz, H., E-mail: israelbaez@gmail.co [Zoz GmbH, D-57482, Wenden (Germany)

    2011-07-01

    The ball milling (B M) of blended Ni and Cr elemental powders was carried out in a Simoloyer performing on high-energy scale mode at maximum production to obtain a nano structured Ni-20Cr alloy. The phase transformations and structural changes occurring during mechanical alloying were investigated by X-ray diffraction (XRD) and optical microscopy (Om). A gradual solid solubility of Cr and the subsequent formation of crystalline metastable solid solutions described in terms of the Avrami-Ero fe ev kinetics model were calculated. The XRD analysis of the structure indicates that cumulative lattice strain contributes to the driving force for solid solution between Ni and Cr during B M. Microstructure evolution has shown, additionally to the lamellar length refinement commonly observed, the folding of lamellae in the final processing stage. Om observations revealed that the lamellar spacing of Ni rich zones reaches a steady value near 500 nm and almost disappears after 30 h of milling. (Author)

  20. Influence of Bulk Carbonaceous Matter on Pluto's Structure and Evolution

    Science.gov (United States)

    McKinnon, W. B.; Stern, S. A.; Weaver, H. A., Jr.; Spencer, J. R.; Moore, J. M.; Young, L. A.; Olkin, C.

    2017-12-01

    The rock/ice mass ratio of the Pluto system is about 2/1 (McKinnon et al., Icarus 287, 2017) [1], though this neglects the potential role of bulk carbonaceous matter ("CHON"), an important cometary component and one likely important in the ancestral Kuiper belt. The wealth of measurements at comet 67P/Churyumov-Gerasimenko (a Jupiter-family comet and thus one formed in the same region of the outer Solar System as Pluto) by Rosetta are particularly instructive. E.g., Davidsson et al. (A&A 592, 2016) [2] propose in their "composition A" that 67P/Ch-G is 25% metal/sulfides, 42% rock/organics, and 32% ice by mass. For their assumed component densities, the overall grain density is 1820 kg/m3. Fulle et al. (MNRAS 462, 2016) [3] posit 5 ± 2 volume % Fe-sulfides of density 4600 kg/m3, 28 ± 5% Mg,Fe-olivines and -pyroxenes of density 3200 kg/m3, 52 ± 12% hydrocarbons of density 1200 kg/m3, and 15 ± 6% ices of 917 kg/m3. This composition yields a primordial grain density (dust + ice) of 1885 ± 240 kg/m3. Both of these cometary density estimates [2,3] are consistent with Pluto-Charon, especially as Pluto's uncompressed (STP) density is close to 1820 kg/m3 and that of the system as a whole is close to 1800 kg/m3 [1]. We consider the potential compositional and structural implications of these proposed 67P/Ch-G compositions when applied to Pluto and Charon. The amount of ice in model A of [2] is a good match to Pluto structural models. Their rock/organics component, however, is taken to be half graphite (2000 kg/m3) by volume. The composition in [3] is more divergent: very ice poor, and on the order of 50% light hydrocarbons by volume. Regardless of the differences between [2] and [3], the possibility of massive internal graphite or carbonaceous layers within Pluto is real. We discuss the possible consequences for Pluto's structure, rock/ice ratio, thermal and chemical evolution, and even interpretation of its gravity field from tectonics. For example, radiogenic heat

  1. Evolution and expression analysis of the soybean glutamate ...

    Indian Academy of Sciences (India)

    Evolution and expression analysis of the soybean glutamate decarboxylase gene family. TAE KYUNG HYUN, SEUNG HEE EOM, XIAO HAN and JU-SUNG KIM http://www.ias.ac.in/jbiosci. J. Biosci. 39(5), December 2014, 899–907, © Indian Academy of Sciences. Supplementary material. Supplementary figure 1.

  2. Xe-135 and Sm-149 isotopic evolution analysis. Xesamo code

    International Nuclear Information System (INIS)

    Caro, R.; Gallego, J.; Martinez Fanegas, R.

    1977-01-01

    The time evolution analysis of the nucleides concentration Xe-135 and Sm-149 as a function of the neutron flux is carried out. The neutron flux may be any function of time. It is analyzed as well the reactivity changes associated with the xenon and samarium concentration variations. (auth) [es

  3. Evolution and expression analysis of the soybean glutamate ...

    Indian Academy of Sciences (India)

    2014-10-20

    Oct 20, 2014 ... regulates pollen germination and polarized tube growth by affecting actin filament pattern, vesicle trafficking, ... results will facilitate our understanding of the evolution of dynamic functions for GmGADs, which ... (4°C) and maintained in a cold room at the same tempera- ture. Samples for RNA analysis were ...

  4. Analysis of the temporal evolution of total column nitrogen dioxide ...

    African Journals Online (AJOL)

    Concurrent measurement and analysis of Nitrogen dioxide (NO2)and Ozone (O3) are essential for improved understanding of ozone distribution. This study sought to analyse the temporal evolution of total column NO2 and O3 over Nairobi using satellite-derived daily data between 2009 and 2013. Seasonality is observed ...

  5. Xe-135 and Sm-149 Isotopic Evolution Analysis Xesamo code

    International Nuclear Information System (INIS)

    Caro, R.; Gallego, J.; Martinez Fanegas, R.

    1977-01-01

    In this report the time evolution analysis of the nuclides concentration Xe-135 and Sm-149 as a function of the neutron flux is carried out. The neutron flux may be any function of time. It is analyzed as well the reactivity changes associated with the xenon and samarium concentration variations. (Author) 5 refs

  6. Evolution of the sedimentation technique for particle size distribution analysis

    International Nuclear Information System (INIS)

    Maley, R.

    1998-01-01

    After an introduction on the significance of particle size measurements, sedimentation methods are described, with emphasis on the evolution of the gravitational approach. The gravitational technique based on mass determination by X-ray adsorption allows fast analysis by automation and easy data handling, in addition to providing the accuracy required by quality control and research applications [it

  7. Contribution for the assessment and simplified calculation of structures taking into account hysteresis evolution

    International Nuclear Information System (INIS)

    Dorka, U.E.

    1988-01-01

    By defining a scalar function of comparison in general and isolating one-dimensional cyclic hysteresis curves for field elements, the foundation is laid for a unified way of judging systems with chain-type structure taking into account hysteresis evolution. A general description of this evolution leads to certain evolutionary properties, with the 'linear' and 'uniform' evolution covering the usual methods for low-cycle fatigue (Miner's rule, Manson-Coffin, Rainflow, etc.). For the more realistic case of an 'exponential' and 'consistent' evolution, experimentally verifiable typ-functions are given which enable with fair accuracy an approximate time-domain computation of a system regarding hysteresis evolution. (orig.) [de

  8. Food web structure and the evolution of ecological communities

    Science.gov (United States)

    Quince, Christopher; Higgs, Paul G.; McKane, Alan J.

    Simulations of the coevolution of many interacting species are performed using the Webworld model. The model has a realistic set of predator-prey equations that describe the population dynamics of the species for any structure of the food web. The equations account for competition between species for the same resources, and for the diet choice of predators between alternative prey according to an evolutionarily stable strategy. The set of species present undergoes long-term evolution d ue to speciation and extinction events. We summarize results obtained on the macro-evolutionary dynamics of speciations and extinctions, and on the statistical properties of the food webs that are generated by the model. Simulations begin from small numbers of species and build up to larger webs with relatively constant species number on average. The rate of origination and extinction of species are relatively high, but remain roughly balanced throughout the simulations. When a 'parent' species undergoes sp eciation, the 'child' species usually adds to the same trophic level as the parent. The chance of the child species surviving is significantly higher if the parent is on the second or third trophic level than if it is on the first level, most likely due to a wider choice of possible prey for species on higher levels. Addition of a new species sometimes causes extinction of existing species. The parent species has a high probability of extinction because it has strong competition with the new species. Non-pa rental competitors of the new species also have a significantly higher extinction probability than average, as do prey of the new species. Predators of the new species are less likely than average to become extinct.

  9. Protein structure and evolution: are they constrained globally by a principle derived from information theory?

    Directory of Open Access Journals (Sweden)

    Leslie Hatton

    Full Text Available That the physicochemical properties of amino acids constrain the structure, function and evolution of proteins is not in doubt. However, principles derived from information theory may also set bounds on the structure (and thus also the evolution of proteins. Here we analyze the global properties of the full set of proteins in release 13-11 of the SwissProt database, showing by experimental test of predictions from information theory that their collective structure exhibits properties that are consistent with their being guided by a conservation principle. This principle (Conservation of Information defines the global properties of systems composed of discrete components each of which is in turn assembled from discrete smaller pieces. In the system of proteins, each protein is a component, and each protein is assembled from amino acids. Central to this principle is the inter-relationship of the unique amino acid count and total length of a protein and its implications for both average protein length and occurrence of proteins with specific unique amino acid counts. The unique amino acid count is simply the number of distinct amino acids (including those that are post-translationally modified that occur in a protein, and is independent of the number of times that the particular amino acid occurs in the sequence. Conservation of Information does not operate at the local level (it is independent of the physicochemical properties of the amino acids where the influences of natural selection are manifest in the variety of protein structure and function that is well understood. Rather, this analysis implies that Conservation of Information would define the global bounds within which the whole system of proteins is constrained; thus it appears to be acting to constrain evolution at a level different from natural selection, a conclusion that appears counter-intuitive but is supported by the studies described herein.

  10. Protein structure and evolution: are they constrained globally by a principle derived from information theory?

    Science.gov (United States)

    Hatton, Leslie; Warr, Gregory

    2015-01-01

    That the physicochemical properties of amino acids constrain the structure, function and evolution of proteins is not in doubt. However, principles derived from information theory may also set bounds on the structure (and thus also the evolution) of proteins. Here we analyze the global properties of the full set of proteins in release 13-11 of the SwissProt database, showing by experimental test of predictions from information theory that their collective structure exhibits properties that are consistent with their being guided by a conservation principle. This principle (Conservation of Information) defines the global properties of systems composed of discrete components each of which is in turn assembled from discrete smaller pieces. In the system of proteins, each protein is a component, and each protein is assembled from amino acids. Central to this principle is the inter-relationship of the unique amino acid count and total length of a protein and its implications for both average protein length and occurrence of proteins with specific unique amino acid counts. The unique amino acid count is simply the number of distinct amino acids (including those that are post-translationally modified) that occur in a protein, and is independent of the number of times that the particular amino acid occurs in the sequence. Conservation of Information does not operate at the local level (it is independent of the physicochemical properties of the amino acids) where the influences of natural selection are manifest in the variety of protein structure and function that is well understood. Rather, this analysis implies that Conservation of Information would define the global bounds within which the whole system of proteins is constrained; thus it appears to be acting to constrain evolution at a level different from natural selection, a conclusion that appears counter-intuitive but is supported by the studies described herein.

  11. Population genomics of dengue virus serotype 4: insights into genetic structure and evolution.

    Science.gov (United States)

    Waman, Vaishali P; Kasibhatla, Sunitha Manjari; Kale, Mohan M; Kulkarni-Kale, Urmila

    2016-08-01

    The spread of dengue disease has become a global public health concern. Dengue is caused by dengue virus, which is a mosquito-borne arbovirus of the genus Flavivirus, family Flaviviridae. There are four dengue virus serotypes (1-4), each of which is known to trigger mild to severe disease. Dengue virus serotype 4 (DENV-4) has four genotypes and is increasingly being reported to be re-emerging in various parts of the world. Therefore, the population structure and factors shaping the evolution of DENV-4 strains across the world were studied using genome-based population genetic, phylogenetic and selection pressure analysis methods. The population genomics study helped to reveal the spatiotemporal structure of the DENV-4 population and its primary division into two spatially distinct clusters: American and Asian. These spatial clusters show further time-dependent subdivisions within genotypes I and II. Thus, the DENV-4 population is observed to be stratified into eight genetically distinct lineages, two of which are formed by American strains and six of which are formed by Asian strains. Episodic positive selection was observed in the structural (E) and non-structural (NS2A and NS3) genes, which appears to be responsible for diversification of Asian lineages in general and that of modern lineages of genotype I and II in particular. In summary, the global DENV-4 population is stratified into eight genetically distinct lineages, in a spatiotemporal manner with limited recombination. The significant role of adaptive evolution in causing diversification of DENV-4 lineages is discussed. The evolution of DENV-4 appears to be governed by interplay between spatiotemporal distribution, episodic positive selection and intra/inter-genotype recombination.

  12. Structure of the Scientific Community Modelling the Evolution of Resistance

    OpenAIRE

    2007-01-01

    Faced with the recurrent evolution of resistance to pesticides and drugs, the scientific community has developed theoretical models aimed at identifying the main factors of this evolution and predicting the efficiency of resistance management strategies. The evolutionary forces considered by these models are generally similar for viruses, bacteria, fungi, plants or arthropods facing drugs or pesticides, so interaction between scientists working on different biological organisms would be expec...

  13. Chromatin structure and evolution in the human genome

    Directory of Open Access Journals (Sweden)

    Dunlop Malcolm G

    2007-05-01

    Full Text Available Abstract Background Evolutionary rates are not constant across the human genome but genes in close proximity have been shown to experience similar levels of divergence and selection. The higher-order organisation of chromosomes has often been invoked to explain such phenomena but previously there has been insufficient data on chromosome structure to investigate this rigorously. Using the results of a recent genome-wide analysis of open and closed human chromatin structures we have investigated the global association between divergence, selection and chromatin structure for the first time. Results In this study we have shown that, paradoxically, synonymous site divergence (dS at non-CpG sites is highest in regions of open chromatin, primarily as a result of an increased number of transitions, while the rates of other traditional measures of mutation (intergenic, intronic and ancient repeat divergence as well as SNP density are highest in closed regions of the genome. Analysis of human-chimpanzee divergence across intron-exon boundaries indicates that although genes in relatively open chromatin generally display little selection at their synonymous sites, those in closed regions show markedly lower divergence at their fourfold degenerate sites than in neighbouring introns and intergenic regions. Exclusion of known Exonic Splice Enhancer hexamers has little affect on the divergence observed at fourfold degenerate sites across chromatin categories; however, we show that closed chromatin is enriched with certain classes of ncRNA genes whose RNA secondary structure may be particularly important. Conclusion We conclude that, overall, non-CpG mutation rates are lowest in open regions of the genome and that regions of the genome with a closed chromatin structure have the highest background mutation rate. This might reflect lower rates of DNA damage or enhanced DNA repair processes in regions of open chromatin. Our results also indicate that dS is a poor

  14. Structural Analysis of Plate Based Tensegrity Structures

    DEFF Research Database (Denmark)

    Hald, Frederik; Kirkegaard, Poul Henning; Damkilde, Lars

    2013-01-01

    Plate tensegrity structures combine tension cables with a cross laminated timber plate and can then form e.g. a roof structure. The topology of plate tensegrity structures is investigated through a parametric investigation. Plate tensegrity structures are investigated, and a method...

  15. Structure and evolution of Apetala3, a sex-linked gene in Silene latifolia

    Directory of Open Access Journals (Sweden)

    Cegan Radim

    2010-08-01

    Full Text Available Abstract Background The evolution of sex chromosomes is often accompanied by gene or chromosome rearrangements. Recently, the gene AP3 was characterized in the dioecious plant species Silene latifolia. It was suggested that this gene had been transferred from an autosome to the Y chromosome. Results In the present study we provide evidence for the existence of an X linked copy of the AP3 gene. We further show that the Y copy is probably located in a chromosomal region where recombination restriction occurred during the first steps of sex chromosome evolution. A comparison of X and Y copies did not reveal any clear signs of degenerative processes in exon regions. Instead, both X and Y copies show evidence for relaxed selection compared to the autosomal orthologues in S. vulgaris and S. conica. We further found that promoter sequences differ significantly. Comparison of the genic region of AP3 between the X and Y alleles and the corresponding autosomal copies in the gynodioecious species S. vulgaris revealed a massive accumulation of retrotransposons within one intron of the Y copy of AP3. Analysis of the genomic distribution of these repetitive elements does not indicate that these elements played an important role in the size increase characteristic of the Y chromosome. However, in silico expression analysis shows biased expression of individual domains of the identified retroelements in male plants. Conclusions We characterized the structure and evolution of AP3, a sex linked gene with copies on the X and Y chromosomes in the dioecious plant S. latifolia. These copies showed complementary expression patterns and relaxed evolution at protein level compared to autosomal orthologues, which suggests subfunctionalization. One intron of the Y-linked allele was invaded by retrotransposons that display sex-specific expression patterns that are similar to the expression pattern of the corresponding allele, which suggests that these transposable elements

  16. Social dilemmas in an online social network: The structure and evolution of cooperation

    International Nuclear Information System (INIS)

    Fu Feng; Chen Xiaojie; Liu Lianghuan; Wang Long

    2007-01-01

    We investigate two paradigms for studying the evolution of cooperation-Prisoner's Dilemma and Snowdrift game in an online friendship network, obtained from a social networking site. By structural analysis, it is revealed that the empirical social network has small-world and scale-free properties. Besides, it exhibits assortative mixing pattern. Then, we study the evolutionary version of the two types of games on it. It is found that cooperation is substantially promoted with small values of game matrix parameters in both games. Whereas the competent cooperators induced by the underlying network of contacts will be dramatically inhibited with increasing values of the game parameters. Further, we explore the role of assortativity in evolution of cooperation by random edge rewiring. We find that increasing amount of assortativity will to a certain extent diminish the cooperation level. We also show that connected large hubs are capable of maintaining cooperation. The evolution of cooperation on empirical networks is influenced by various network effects in a combined manner, compared with that on model networks. Our results can help understand the cooperative behaviors in human groups and society

  17. Earth's structure and evolution inferred from topography, gravity, and seismicity.

    Science.gov (United States)

    Watkinson, A. J.; Menard, J.; Patton, R. L.

    2016-12-01

    Earth's wavelength-dependent response to loading, reflected in observed topography, gravity, and seismicity, can be interpreted in terms of a stack of layers under the assumption of transverse isotropy. The theory of plate tectonics holds that the outermost layers of this stack are mobile, produced at oceanic ridges, and consumed at subduction zones. Their toroidal motions are generally consistent with those of several rigid bodies, except in the world's active mountain belts where strains are partitioned and preserved in tectonite fabrics. Even portions of the oceanic lithosphere exhibit non-rigid behavior. Earth's gravity-topography cross-spectrum exhibits notable variations in signal amplitude and character at spherical harmonic degrees l=13, 116, 416, and 1389. Corresponding Cartesian wavelengths are approximately equal to the respective thicknesses of Earth's mantle, continental mantle lithosphere, oceanic thermal lithosphere, and continental crust, all known from seismology. Regional variations in seismic moment release with depth, derived from the global Centroid Moment Tensor catalog, are also evident in the crust and mantle lithosphere. Combined, these observations provide powerful constraints for the structure and evolution of the crust, mantle lithosphere, and mantle as a whole. All that is required is a dynamically consistent mechanism relating wavelength to layer thickness and shear-strain localization. A statistically-invariant 'diharmonic' relation exhibiting these properties appears as the leading order approximation to toroidal motions on a self-gravitating body of differential grade-2 material. We use this relation, specifically its predictions of weakness and rigidity, and of folding and shear banding response as a function of wavelength-to-thickness ratio, to interpret Earth's gravity, topography, and seismicity in four-dimensions. We find the mantle lithosphere to be about 255-km thick beneath the Himalaya and the Andes, and the long

  18. Structural Analysis of Communication Development.

    Science.gov (United States)

    Conville, Richard L.

    This paper discusses the question of the legitimacy of applying structural analysis to actual human behavior and illustrates its legitimacy by using the reasoning in an essay by Paul Ricoeur. It then asks if the principles of communication development (obliqueness, exchange, and dying) derived from Helen Keller's experience of communication…

  19. Focused Evolution of HIV-1 Neutralizing Antibodies Revealed by Structures and Deep Sequencing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xueling; Zhou, Tongqing; Zhu, Jiang; Zhang, Baoshan; Georgiev, Ivelin; Wang, Charlene; Chen, Xuejun; Longo, Nancy S.; Louder, Mark; McKee, Krisha; O’Dell, Sijy; Perfetto, Stephen; Schmidt, Stephen D.; Shi, Wei; Wu, Lan; Yang, Yongping; Yang, Zhi-Yong; Yang, Zhongjia; Zhang, Zhenhai; Bonsignori, Mattia; Crump, John A.; Kapiga, Saidi H.; Sam, Noel E.; Haynes, Barton F.; Simek, Melissa; Burton, Dennis R.; Koff, Wayne C.; Doria-Rose, Nicole A.; Connors, Mark; Mullikin, James C.; Nabel, Gary J.; Roederer, Mario; Shapiro, Lawrence; Kwong, Peter D.; Mascola, John R. (Tumaini); (NIH); (Duke); (Kilimanjaro Repro.); (IAVI)

    2013-03-04

    Antibody VRC01 is a human immunoglobulin that neutralizes about 90% of HIV-1 isolates. To understand how such broadly neutralizing antibodies develop, we used x-ray crystallography and 454 pyrosequencing to characterize additional VRC01-like antibodies from HIV-1-infected individuals. Crystal structures revealed a convergent mode of binding for diverse antibodies to the same CD4-binding-site epitope. A functional genomics analysis of expressed heavy and light chains revealed common pathways of antibody-heavy chain maturation, confined to the IGHV1-2*02 lineage, involving dozens of somatic changes, and capable of pairing with different light chains. Broadly neutralizing HIV-1 immunity associated with VRC01-like antibodies thus involves the evolution of antibodies to a highly affinity-matured state required to recognize an invariant viral structure, with lineages defined from thousands of sequences providing a genetic roadmap of their development.

  20. Piece2.0: an update for the pant gene structure comparison and evolution database

    Science.gov (United States)

    PIECE (Plant Intron Exon Comparison and Evolution) is a web-accessible database that houses intron and exon information of plant genes. PIECE serves as a resource for biologists interested in comparing intron–exon organization and provides valuable insights into the evolution of gene structure in pl...

  1. Phosphotyrosine phosphatase R3 receptors: Origin, evolution and structural diversification.

    Directory of Open Access Journals (Sweden)

    Javier U Chicote

    Full Text Available Subtype R3 phosphotyrosine phosphatase receptors (R3 RPTPs are single-spanning membrane proteins characterized by a unique modular composition of extracellular fibronectin repeats and a single cytoplasmatic protein tyrosine phosphatase (PTP domain. Vertebrate R3 RPTPs consist of five members: PTPRB, PTPRJ, PTPRH and PTPRO, which dephosphorylate tyrosine residues, and PTPRQ, which dephosphorylates phophoinositides. R3 RPTPs are considered novel therapeutic targets in several pathologies such as ear diseases, nephrotic syndromes and cancer. R3 RPTP vertebrate receptors, as well as their known invertebrate counterparts from animal models: PTP52F, PTP10D and PTP4e from the fruitfly Drosophila melanogaster and F44G4.8/DEP-1 from the nematode Caenorhabditis elegans, participate in the regulation of cellular activities including cell growth and differentiation. Despite sharing structural and functional properties, the evolutionary relationships between vertebrate and invertebrate R3 RPTPs are not fully understood. Here we gathered R3 RPTPs from organisms covering a broad evolutionary distance, annotated their structure and analyzed their phylogenetic relationships. We show that R3 RPTPs (i have probably originated in the common ancestor of animals (metazoans, (ii are variants of a single ancestral gene in protostomes (arthropods, annelids and nematodes; (iii a likely duplication of this ancestral gene in invertebrate deuterostomes (echinodermes, hemichordates and tunicates generated the precursors of PTPRQ and PTPRB genes, and (iv R3 RPTP groups are monophyletic in vertebrates and have specific conserved structural characteristics. These findings could have implications for the interpretation of past studies and provide a framework for future studies and functional analysis of this important family of proteins.

  2. A Critical Analysis of Chromotherapy and Its Scientific Evolution

    OpenAIRE

    Azeemi, Samina T. Yousuf; Raza, Mohsin

    2005-01-01

    Chromotherapy is a method of treatment that uses the visible spectrum (colors) of electromagnetic radiation to cure diseases. It is a centuries-old concept used successfully over the years to cure various diseases. We have undertaken a critical analysis of chromotherapy and documented its scientific evolution to date. A few researchers have tried to discover the underlying scientific principles, but without quantitative study. Sufficient published material can be found about the subject t...

  3. Functional Analysis and Evolution Equations Dedicated to Gunter Lumer

    CERN Document Server

    Amann, Herbert; Hieber, Matthias

    2008-01-01

    GA1/4nter Lumer was an outstanding mathematician whose work has great influence on the research community in mathematical analysis and evolution equations. He was at the origin of the breath-taking development the theory of semigroups saw after the pioneering book of Hille and Phillips of 1957. This volume contains invited contributions presenting the state of the art of these topics and reflecting the broad interests of GA1/4nter Lumer.

  4. The Evolution of Altruism in Spatially Structured Populations

    NARCIS (Netherlands)

    Németh, András; Takács, Károly

    2007-01-01

    The evolution of altruism in humans is still an unresolved puzzle. Helping other individuals is often kinship-based or reciprocal. Several examples show, however, that altruism goes beyond kinship and reciprocity and people are willing to support unrelated others even when this is at a cost and they

  5. Code Flows : Visualizing Structural Evolution of Source Code

    NARCIS (Netherlands)

    Telea, Alexandru; Auber, David

    2008-01-01

    Understanding detailed changes done to source code is of great importance in software maintenance. We present Code Flows, a method to visualize the evolution of source code geared to the understanding of fine and mid-level scale changes across several file versions. We enhance an existing visual

  6. Structural Analysis of Complex Networks

    CERN Document Server

    Dehmer, Matthias

    2011-01-01

    Filling a gap in literature, this self-contained book presents theoretical and application-oriented results that allow for a structural exploration of complex networks. The work focuses not only on classical graph-theoretic methods, but also demonstrates the usefulness of structural graph theory as a tool for solving interdisciplinary problems. Applications to biology, chemistry, linguistics, and data analysis are emphasized. The book is suitable for a broad, interdisciplinary readership of researchers, practitioners, and graduate students in discrete mathematics, statistics, computer science,

  7. Efficient Analysis of Complex Structures

    Science.gov (United States)

    Kapania, Rakesh K.

    2000-01-01

    Last various accomplishments achieved during this project are : (1) A Survey of Neural Network (NN) applications using MATLAB NN Toolbox on structural engineering especially on equivalent continuum models (Appendix A). (2) Application of NN and GAs to simulate and synthesize substructures: 1-D and 2-D beam problems (Appendix B). (3) Development of an equivalent plate-model analysis method (EPA) for static and vibration analysis of general trapezoidal built-up wing structures composed of skins, spars and ribs. Calculation of all sorts of test cases and comparison with measurements or FEA results. (Appendix C). (4) Basic work on using second order sensitivities on simulating wing modal response, discussion of sensitivity evaluation approaches, and some results (Appendix D). (5) Establishing a general methodology of simulating the modal responses by direct application of NN and by sensitivity techniques, in a design space composed of a number of design points. Comparison is made through examples using these two methods (Appendix E). (6) Establishing a general methodology of efficient analysis of complex wing structures by indirect application of NN: the NN-aided Equivalent Plate Analysis. Training of the Neural Networks for this purpose in several cases of design spaces, which can be applicable for actual design of complex wings (Appendix F).

  8. AfricaArray seismological studies of the structure and evolution of the African continent

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2013-10-01

    Full Text Available The AfricaArray programme seeks to build geoscience capacity and conduct research that supports development in Africa. This paper reports on investigations of the structure and evolution of the African continent that have been concluded since...

  9. Analysis of the Science and Technology Preservice Teachers' Opinions on Teaching Evolution and Theory of Evolution

    Science.gov (United States)

    Töman, Ufuk; Karatas, Faik Özgür; Çimer, Sabiha Odabasi

    2014-01-01

    In this study, we investigate of science and technology teachers' opinions about the theory of evolution and the evolution teaching. The aim of this study, we investigate of science and technology teachers' opinions about the theory of evolution and the evolution teaching. This study is a descriptive study. Open-ended questions were used to…

  10. Stereological analysis of spatial structures

    DEFF Research Database (Denmark)

    Hansen, Linda Vadgård

    The thesis deals with stereological analysis of spatial structures. One area of focus has been to improve the precision of well-known stereological estimators by including information that is available via automatic image analysis. Furthermore, the thesis presents a stochastic model for star......-shaped three-dimensional objects using the radial function. It appears that the model is highly fleksiblel in the sense that it can be used to describe an object with arbitrary irregular surface. Results on the distribution of well-known local stereological volume estimators are provided....

  11. Artificial selection for structural color on butterfly wings and comparison with natural evolution

    OpenAIRE

    Wasik, Bethany R.; Liew, Seng Fatt; Lilien, David A.; Dinwiddie, April J.; Noh, Heeso; Cao, Hui; Monteiro, Antónia

    2014-01-01

    Despite significant efforts to study structural colors in nature, little is known about how such colors and structures evolved in the first place. To address this key question, we performed the first artificial selection (to our knowledge) on a structural color using butterflies. We demonstrated rapid evolution of violet structural color from ultra-violet brown scales in Bicyclus anynana butterflies with only six generations of selection. Furthermore, we identified the structural changes resp...

  12. Molecular evolution, intracellular organization, and the quinary structure of proteins.

    OpenAIRE

    McConkey, E H

    1982-01-01

    High-resolution two-dimensional polyacrylamide gel electrophoresis shows that at least half of 370 denatured polypeptides from hamster cells and human cells are indistinguishable in terms of isoelectric points and molecular weights. Molecular evolution may have been more conservative for this set of proteins than sequence studies on soluble proteins have implied. This may be a consequence of complexities of intracellular organization and the numerous macromolecular interactions in which most ...

  13. Analysis on evolution and research focus in psychiatry field.

    Science.gov (United States)

    Wu, Ying; Duan, Zhiguang

    2015-05-07

    With the dramatic rise in mental disorders and mental illnesses, psychiatry has become one of the fastest growing clinical medical disciplines. This has led to a rise in the number of scientific research papers being published in this field. We selected research papers in ten psychiatric journals that were published during 1983 to 2012. These ten journals were those with the top Impact Factor (IF) as indicated by the Science Citation Index Expanded (SCI-Expanded). We utilized information visualization software (CiteSpace) to conduct co-citation and Hierarchal clustering analysis to map knowledge domains to determine the evolution and the foci of research in this field. In the evolution of the field of psychiatry, there were four stages identified. The result of hierarchal clustering analysis revealed that the research foci in the psychiatric field were primarily studies of child and adolescent psychiatry, diagnostic and classification criteria, brain imaging and molecular genetics. The results provide information about the evolution and the foci of the research in the field of psychiatry. This information can help researchers determine the direction of the research in the field of psychiatry; Moreover, this research provides reasonable suggestions to guide research in psychiatry field and provide scientific evidence to aid in the effective prevention and treatment of mental disorders.

  14. Structure, evolution and expression of collagen XXVIII: Lessons from the zebrafish.

    Science.gov (United States)

    Gebauer, Jan M; Kobbe, Birgit; Paulsson, Mats; Wagener, Raimund

    2016-01-01

    Collagen XXVIII is the last discovered member of the collagen superfamily and thus has been only sparsely investigated. We studied collagen XXVIII in zebrafish to gain insight into its structure, evolution and expression. In contrast to human and mouse, the zebrafish genome contains four collagen XXVIII genes, col28a1a and -b, and col28a2a and -b. Genomic context and phylogenetic analysis revealed that the a2 branch was lost during evolution of mammals, whereas the duplication of the a1 and a2 branches results from the whole genome duplication in the teleost lineage. Sequence analysis revealed conservation of domain structure and the unique imperfections in the triple helical domain. Two major forms of collagen XXVIII were identified, Col28a1b in adult and Col28a2a in 3-5dpf zebrafish. Composite agarose/polyacrylamide gel electrophoresis revealed that both these chains mainly form dimers of trimers, although Col28a1b appears to be more polydisperse. Homodimers are abundant, although it is possible that complexes consisting of Col28a2a and Col28a1a or -a2b occur. Peptide mass fingerprint analysis revealed that the C-terminal Kunitz domain is often proteolytically processed. In contrast to murine collagen XXVIII, the zebrafish orthologs are widely expressed and not only present in the nervous system. They are differentially expressed in the liver, thymus, muscle, intestine and skin. Altogether our results point to a unique nature of collagen XXVIII within the collagen family. Copyright © 2015 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

  15. Structural Evolution and Stability of Sol-Gel Biocatalysts

    International Nuclear Information System (INIS)

    Rodgers, L.E.; Foster, L.J.R.; Holden, P.J.; Knott, R.B.; Bartlett, J.B.

    2005-01-01

    Full text: Immobilisation strategies for catalytic enzymes are important as they allow reuse of the biocatalysts. Sol-gel materials have been used to immobilise Candida antarctica lipase B (CALB), a commonly used industrial enzyme with a known crystal structure. The sol-gel bioencapsulate is produced through the condensation of suitable metal alkoxides in the presence of CALB, yielding materials with controlled pore sizes, volume and surface chemistry. Sol-gel matrices have been shown to prolong the catalytic life and enhance the activity of CALB, although the molecular basis for this effect has yet to be elucidated due to the limitations of analysis techniques applied to date. Small angle neutron scattering (SANS) allows such multicomponent systems to be characterised through contrast matching. In the sol-gel bioencapsulate system, at the contrast match point for silica, residual scattering intensity is due to the CALB and density fluctuations in the matrix. A SANS contrast variation series found the match point for the silica matrix, both with and without enzyme present, to be around 35 percent. The model presented here proposes a mechanism for the interaction between CALB and the surrounding sol-gel matrix, and the observed improvement in enzyme activity and matrix strength. The SANS protocol developed here may be applied more generally to bioencapsulates. (authors)

  16. [Genomic structure of the autotetraploid oat species Avena macrostachya inferred from comparative analysis of the ITS1 and ITS2 sequences: on the oat karyotype evolution during the early stages of the Avena species divergence].

    Science.gov (United States)

    Rodionov, A V; Tiupa, N B; Kim, E S; Machs, E M; Loskutov, I G

    2005-05-01

    To examine the genomic structure of Avena macrostachya, internal transcribed spacers, ITS1 and ITS2, as well as nuclear 5.8S tRNA genes from three oat species with AsAs karyotype (A. wiestii, A. hirtula, and A. atlantica), and those from A. longiglumis (AlAl), A. canariensis (AcAc), A. ventricosa (CvCv), A. pilosa, and A. clauda (CpCp) were sequenced. All species of the genus Avena examined represented a monophyletic group (bootstrap index = 98), within which two branches, i.e., species with A- and C-genomes, were distinguished (bootstrap indices = 100). The subject of our study, A. macrostachya, albeit belonging to the phylogenetic branch of C-genome oat species (karyotype with submetacentic and subacrocentric chromosomes), has preserved an isobrachyal karyotype, (i.e., that containing metacentric chromosomes), probably typical of the common Avena ancestor. It was suggested to classify the A. macrostachya genome as a specific form of C-genome, Cm-genome. Among the species from other genera studied, Arrhenatherum elatius was found to be the closest to Avena in ITS1 and ITS structure. Phylogenetic relationships between Avena and Helictotrichon remain intriguingly uncertain. The HPR389153 sequence from H. pratense genome was closest to the ITS1 sequences specific to the Avena A-genomes (p-distance = 0.0237), while the differences of this sequence from the ITS1 of A. macrostachya reached 0.1221. On the other hand, HAD389117 from H. adsurgens was close to the ITS1 specific to Avena C-genomes (p-distance = 0.0189), while its differences from the A-genome specific ITS1 sequences reached 0.1221. It seems likely that the appearance of highly polyploid (2n = 12-21x) species of H. pratense and H. adsurgens could be associated with interspecific hybridization involving Mediterranean oat species carrying A- and C-genomes. A hypothesis on the pathways of Avena chromosomes evolution during the early stages the oat species divergence is proposed.

  17. Detection of structural damage in multiwire cables by monitoring the entropy evolution of wavelet coefficients

    Science.gov (United States)

    Ibáñez, Flor; Baltazar, Arturo; Mijarez, Rito; Aranda, Jorge

    2015-03-01

    Multiwire cables are widely used in important civil structures. Since they are exposed to several dynamic and static loads, their structural health can be compromised. The cables can also be submitted to mechanical contact, tension and energy propagation in addition to changes in size and material within their wires. Due to the critical role played by multiwire cables, it is necessary to develop a non-destructive health monitoring method to maintain their structure and proper performance. Ultrasonic inspection using guided waves is a promising non-destructive damage monitoring technique for rods, single wires and multiwire cables. The propagated guided waves are composed by an infinite number of vibrational modes making their analysis difficult. In this work, an entropy-based method to identify small changes in non-stationary signals is proposed. A system to capture and post-process acoustic signals is implemented. The Discrete Wavelet Transform (DWT) is computed in order to obtain the reconstructed wavelet coefficients of the signals and to analyze the energy at different scales. The feasibility of using the concept of entropy evolution of non-stationary signals to detect damage in multiwire cables is evaluated. The results show that there is a high correlation between the entropy value and damage level of the cable. The proposed method has low sensitivity to noise and reduces the computational complexity found in a typical time-frequency analysis.

  18. Structural Evolution of the Eastern Sierra Madre Oriental: The Role of Basement Structures in Fold-Thrust Development

    Science.gov (United States)

    Hamade, A.; Murphy, M. A.; Hall, S.

    2006-12-01

    Investigations worldwide show that basement plays an important role in the evolution of fold-thrust belts and recognizing their structural development leads to better understanding of zones of intercontinental deformation. Two explanations have been proposed to explain uplift of basement rocks in the Sierra Madre Oriental (SMO) fold-thrust belt, 1) basement rocks are uplifted along high-angle reverse faults (Laramide-style) which postdate a thin-skinned phase of deformation; and 2) basement rocks are carried in deeper-rooted thrust sheets during the thin-skinned phase of deformation. A structural study in the SMO fold-thrust belt that integrates field mapping, structural analysis, and gravity modeling was conducted to distinguish between the two explanations. The study area lies in the southern section of the state of Nuevo Leon near the town of Aramberri. In this area the fold-thrust belt involves upper Cretaceous shale, Mesozoic carbonate rocks and crystalline basement. Thrusting is directed approximately due east. The structural style is characterized by fault bend folds. Mapping shows that evaporite rocks, at least locally, are not exploited as a regional slip surface and the thrust fault roots into the basement. Cross-sections across the study area indicate approximately 6.5 km east-west shortening (19%). Three forward 2-D structural models aid in constraining the fault geometry at depth and show the reactivation of half graben faults as a means for the main thrust to step up to shallower levels. These data are consistent with a single phase of deformation which involves movement along a thrust system that creates the structure in the study area implying magnitude of depth to detachment to be greater for this area of the SMO.

  19. Enhanced dewaterability of sludge during anaerobic digestion with thermal hydrolysis pretreatment: New insights through structure evolution.

    Science.gov (United States)

    Zhang, Jingsi; Li, Ning; Dai, Xiaohu; Tao, Wenquan; Jenkinson, Ian R; Li, Zhuo

    2017-12-19

    Comprehensive insights into the sludge digestate dewaterability were gained through porous network structure of sludge. We measured the evolution of digestate dewaterability, represented by the solid content of centrifugally dewatered cake, in high-solids sequencing batch digesters with and without thermal hydrolysis pretreatment (THP). The results show that the dewaterability of the sludge after digestion was improved by 3.5% (±0.5%) for unpretreated sludge and 5.1% (±0.4%) for thermally hydrolyzed sludge. Compared to the unpretreated sludge digestate, thermal hydrolysis pretreatment eventually resulted in an improvement of dewaterability by 4.6% (±0.5%). Smaller particle size and larger surface area of sludge were induced by thermal hydrolysis and anaerobic digestion treatments. The structure strength and compactness of sludge, represented by elastic modulus and fractal dimension respectively, decreased with increase of digestion time. The porous network structure was broken up by thermal hydrolysis pretreatment and was further weakened during anaerobic digestion, which correspondingly improved the dewaterability of digestates. The logarithm of elastic modulus increased linearly with fractal dimension regardless of the pretreatment. Both fractal dimension and elastic modulus showed linear relationship with dewaterability. The rheological characterization combined with the analysis of fractal dimension of sewage sludge porous network structure was found applicable in quantitative evaluation of sludge dewaterability, which depended positively on both thermal hydrolysis and anaerobic digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Structural evolution of three geopressured-geothermal areas in the Texas Gulf Coast

    Energy Technology Data Exchange (ETDEWEB)

    Winker, C.D.; Morton, R.A.; Garcia, D.D.

    1981-01-01

    Detailed analysis of geological and seismic data from several geopressured geothermal areas (Cuero, Blessing, Pleasant Bayou) reveals similarities in structural-stratigraphic relationships that form geopressured aquifers as well as differences in structural complexity and evolution that characterize the different areas. In these examples, geopressured sandstones are isolated on the updip side by downfaulting against shelf-slope shales, and on the downdip side by upfaulting against transgressive marine shales. Moreover, they are isolated above and below by thick sequences of transgressive shale or interbedded sandstone and shale. Prospective reservoirs are found where delatic and associated sandstones (distributary channel, delta front, barrie-strandplain) were deposited seaward of major growth faults and near the shelf margin. Structural development in these areas began with rapid movement of relatively straight to sinuous down-to-the basin growth faults with narrow to wide spacings and varying amounts of rollover. Later structural movement was characterized by continued but slower movement of most growth faults. In the Pleasant Bayou area, late salt diapirism superimposed a dome-and-withdrawal-basin pattern on the earlier growth-fault style.

  1. Structural Analysis of Fungal Cerebrosides

    Directory of Open Access Journals (Sweden)

    Eliana eBarreto-Bergter

    2011-12-01

    Full Text Available Of the ceramide monohexosides (CMHs, gluco- and galactosylceramides are the main neutral glycosphingolipids expressed in fungal cells. Their structural determination is greatly dependent on the use of mass spectrometric techniques, including fast atom bombardment-mass spectrometry (FAB-MS, electrospray ionization (ESI-MS, and energy collision-induced dissociation mass spectrometry (ESI-MS/CID-MS. Nuclear magnetic resonance (NMR has also been used successfully. Such a combination of techniques, combined with classical analytical separation, such as HPTLC and column chromatography, has led to the structural elucidation of a great number of fungal CMHs. The structure of fungal CMH is conserved among fungal species and consists of a glucose or galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to hydroxylated fatty acids, most commonly having 16 or 18 carbon atoms and unsaturation between C-3 and C-4. Along with their unique structural characteristics, fungal CMHs have a peculiar subcellular distribution and striking biological properties. Fungal cerebrosides were also characterized as antigenic molecules directly or indirectly involved in cell growth or differentiation in Schizophyllum commune, Cryptococcus neoformans, Pseudallescheria boydii, Candida albicans, Aspergillus nidulans, A.fumigatus and Colletotrichum gloeosporioides. Besides classical techniques for cerebroside (CMH analysis, we now describe new approaches, combining conventional TLC and mass spectrometry, as well as emerging technologies for subcellular localization and distribution of glycosphingolipids by SIMS and imaging MALDI TOF .

  2. Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications.

    Science.gov (United States)

    Barthlott, W; Mail, M; Neinhuis, C

    2016-08-06

    A comprehensive survey of the construction principles and occurrences of superhydrophobic surfaces in plants, animals and other organisms is provided and is based on our own scanning electron microscopic examinations of almost 20 000 different species and the existing literature. Properties such as self-cleaning (lotus effect), fluid drag reduction (Salvinia effect) and the introduction of new functions (air layers as sensory systems) are described and biomimetic applications are discussed: self-cleaning is established, drag reduction becomes increasingly important, and novel air-retaining grid technology is introduced. Surprisingly, no evidence for lasting superhydrophobicity in non-biological surfaces exists (except technical materials). Phylogenetic trees indicate that superhydrophobicity evolved as a consequence of the conquest of land about 450 million years ago and may be a key innovation in the evolution of terrestrial life. The approximate 10 million extant species exhibit a stunning diversity of materials and structures, many of which are formed by self-assembly, and are solely based on a limited number of molecules. A short historical survey shows that bionics (today often called biomimetics) dates back more than 100 years. Statistical data illustrate that the interest in biomimetic surfaces is much younger still. Superhydrophobicity caught the attention of scientists only after the extreme superhydrophobicity of lotus leaves was published in 1997. Regrettably, parabionic products play an increasing role in marketing.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. © 2016 The Author(s).

  3. Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications

    Science.gov (United States)

    Mail, M.; Neinhuis, C.

    2016-01-01

    A comprehensive survey of the construction principles and occurrences of superhydrophobic surfaces in plants, animals and other organisms is provided and is based on our own scanning electron microscopic examinations of almost 20 000 different species and the existing literature. Properties such as self-cleaning (lotus effect), fluid drag reduction (Salvinia effect) and the introduction of new functions (air layers as sensory systems) are described and biomimetic applications are discussed: self-cleaning is established, drag reduction becomes increasingly important, and novel air-retaining grid technology is introduced. Surprisingly, no evidence for lasting superhydrophobicity in non-biological surfaces exists (except technical materials). Phylogenetic trees indicate that superhydrophobicity evolved as a consequence of the conquest of land about 450 million years ago and may be a key innovation in the evolution of terrestrial life. The approximate 10 million extant species exhibit a stunning diversity of materials and structures, many of which are formed by self-assembly, and are solely based on a limited number of molecules. A short historical survey shows that bionics (today often called biomimetics) dates back more than 100 years. Statistical data illustrate that the interest in biomimetic surfaces is much younger still. Superhydrophobicity caught the attention of scientists only after the extreme superhydrophobicity of lotus leaves was published in 1997. Regrettably, parabionic products play an increasing role in marketing. This article is part of the themed issue ‘Bioinspired hierarchically structured surfaces for green science’. PMID:27354736

  4. Tridimensional model structure and patterns of molecular evolution of Pepino mosaic virus TGBp3 protein.

    Science.gov (United States)

    Hasiów-Jaroszewska, Beata; Czerwoniec, Anna; Pospieszny, Henryk; Elena, Santiago F

    2011-06-24

    Pepino mosaic virus (PepMV) is considered one of the most dangerous pathogens infecting tomatoes worldwide. The virus is highly diverse and four distinct genotypes, as well as inter-strain recombinants, have already been described. The isolates display a wide range on symptoms on infected plant species, ranging from mild mosaic to severe necrosis. However, little is known about the mechanisms and pattern of PepMV molecular evolution and about the role of individual proteins in host-pathogen interactions. The nucleotide sequences of the triple gene block 3 (TGB3) from PepMV isolates varying in symptomatology and geographic origin have been analyzed. The modes and patterns of molecular evolution of the TGBp3 protein were investigated by evaluating the selective constraints to which particular amino acid residues have been subjected during the course of diversification. The tridimensional structure of TGBp3 protein has been modeled de novo using the Rosetta algorithm. The correlation between symptoms development and location of specific amino acids residues was analyzed. The results have shown that TGBp3 has been evolving mainly under the action of purifying selection operating on several amino acid sites, thus highlighting its functional role during PepMV infection. Interestingly, amino acid 67, which has been previously shown to be a necrosis determinant, was found to be under positive selection. Identification of diverse selection events in TGB3p3 will help unraveling its biological functions and is essential to an understanding of the evolutionary constraints exerted on the Potexvirus genome. The estimated tridimensional structure of TGBp3 will serve as a platform for further sequence, structural and function analysis and will stimulate new experimental advances.

  5. Effects of Melt Processing on Evolution of Structure in PEEK

    Science.gov (United States)

    Georgiev, Georgi; Dai, Patrick Shuanghua; Oyebode, Elizabeth; Cebe, Peggy; Capel, Malcolm

    1999-01-01

    We report on the effects of melt processing temperature on structure formation in Poly(ether-ether-ketone), PEEK. Real time Small Angle X-ray Scattering, SAXS, and thermal analysis are used to follow the melting behavior after various stages of processing. Assignment of peaks to structural entities within the material, the relative perfection of the crystals, and the possibility of their reorganization, are all influenced by the melt processing history. With the advent of high intensity synchrotron sources of X-radiation, polymer scientists gain a research tool which, when used along with thermal analysis, provides additional structural information about the crystals during growth and subsequent melting. PEEK is an engineering thermoplastic polymer with a very high glass transition temperature (145 C) and crystal melting point (337 C). PEEK has been the subject of recent studies by X-ray scattering in which melt and cold crystallization were followed in real-time. X-ray scattering and thermal studies have been used to address the formation of dual endothermic response which has been variously ascribed to lamellar insertion, dual crystal populations, or melting followed by re-crystallization. Another important issue is whether all of the amorphous phase is located in interlamellar regions, or alternatively whether some is located in "pockets" away from the crystalline lamellar stacks. The interpretation of scattering from lamellar stacks varies depending upon whether such amorphous pockets are formed. Some groups believe all of the amorphous phase is interlamellar. This leads to selection of a smaller thickness for the crystals. Other groups suggest that most amorphous phase is not interlamellar, and this leads to the suggestion that the crystal thickness is larger than the amorphous layer within the stacks. To investigate these ideas, we used SAXS and Differential Scanning Calorimetry to compare results of single and dual stage melt crystallization of PEEK using a

  6. Evolution and Structure of Neuromuscular Systems in Spiralian Meiofauna

    DEFF Research Database (Denmark)

    Bekkouche, Nicolas Tarik

    difficult to resolve and understand. The present thesis focuses on spiralian meiofauna to i) reconstruct the phylogeny of this clade using transcriptomics and place enigmatic meiofaunal taxa and ii) resolve the morphology of three important taxa, mainly employing confocal laser scanning microscopy...... representatives, that Gnathifera is the sister group of remaining Spiralia, that Gastrotricha+Platyhelminthes branches off next and that Lobatocerebrum is an Annelida. The morphological surveys of the musculature, nervous system, glands, and ciliation on three phylogenetically distinct taxa yield more insight...... such as the ciliary pattern or a system of pharyngeal canals of possible importance for future comparative approaches. These different studies show that information on rare and phylogenetically isolated animals with their unique combination of neural and muscular characters are necessary to understand the evolution...

  7. Origin, evolution, and structure of the giant planets

    International Nuclear Information System (INIS)

    Stevenson, D.J.

    1986-01-01

    Jupiter and Saturn are adiabatic spheres of hydrogen and helium, with central concentrations of heavier elements of the order of 10 earth masses. Uranus and Neptune are ice-rich by comparison and have masses comparable to the cores of Jupiter and Saturn. It is argued that these planets started out substantially hotter than at present and have since been gradually cooling. It is also argued that the high-density cores of Jupiter and Saturn are primordial and might be the nuclei that promoted gaseous accretion and led to the current large masses of these planets. In this review, emphasis is placed on the basic ideas needed to construct static and evolving models, and an assessment is made of the relationship between these models and current ideas for the formation and evolution of the solar system. 28 references

  8. Magnetic structure evolution in mechanically milled nanostructured ZnFe2O4 particles

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Wynn, P.; Mørup, Steen

    1999-01-01

    Nanostructured partially-inverted ZnFe2O4 particles have been prepared from bulk ZnFe2O4 by high-energy ball milling in an open container. The grain size reduction, cation site distributions, and the evolution of magnetic structures have been studied by x-ray diffraction with Rietveld structure...

  9. Structural Evolution of Human Recombinant alfaB-Crystallin under UV Irradiation

    DEFF Research Database (Denmark)

    Sugiyama, Masaaki; Fujii, Noriko; Morimoto, Yukio

    2008-01-01

    External stresses cause certain proteins to lose their regular structure and aggregate. In order to clarify this abnormal aggregation process, a structural evolution of human recombinant aB-crystallin under UV irradiation was observed with in situ small-angle neutron scattering. The abnormal...

  10. On modeling micro-structural evolution using a higher order strain gradient continuum theory

    DEFF Research Database (Denmark)

    El-Naaman, S. A.; Nielsen, K. L.; Niordson, C. F.

    2016-01-01

    the experimentally observed micro-structural behavior, within a framework based on continuous field quantities, poses obvious challenges, since the evolution of dislocation structures is inherently a discrete and discontinuous process. This challenge, in particular, motivates the present study, and the aim...

  11. Dynamic analysis of embedded structures

    International Nuclear Information System (INIS)

    Kausel, E.; Whitman, R.V.; Morray, J.P.

    1977-01-01

    The paper presents simplified rules to account for embeddment and soil layering in the soil-structure interaction problem, to be used in dynamic analysis. The relationship between the spring method, and a direct solution (in which both soil and structure are modeled with finite elements and linear members) is first presented. It is shown that for consistency of the results with the two solution methods the spring method should be performed in the following three steps: 1. Determination of the motion of the massless foundation (having the same shape as the actual one) when subjected to the same input motion as the direct solution. 2. Determination of the frequency dependent subgrade stiffness for the relevant degrees of freedom. 3. Computations of the response of the real structure supported on frequency dependent soil springs and subjected at the base of these springs to the motion computed in step 1. The first two steps require, in general, finite element methods, which would make the procedure not attractive. It is shown in the paper, however, that excellent approximations can be obtained, on the basis of 1-dimensional wave propagation theory for the solution of step 1, and correction factors modifying for embeddment the corresponding springs of a surface footing on a layered stratum, for the solution of step 2. (Auth.)

  12. Gene finding with a hidden Markov model of genome structure and evolution

    DEFF Research Database (Denmark)

    Pedersen, Jakob Skou; Hein, Jotun

    2003-01-01

    the model are linear in alignment length and genome number. The model is applied to the problem of gene finding. The benefit of modelling sequence evolution is demonstrated both in a range of simulations and on a set of orthologous human/mouse gene pairs. AVAILABILITY: Free availability over the Internet...... annotation. The modelling of evolution by the existing comparative gene finders leaves room for improvement. Results: A probabilistic model of both genome structure and evolution is designed. This type of model is called an Evolutionary Hidden Markov Model (EHMM), being composed of an HMM and a set of region...

  13. Astronomical constraints on the cosmic evolution of the fine structure constant and possible quantum dimensions.

    Science.gov (United States)

    Carilli, C L; Menten, K M; Stocke, J T; Perlman, E; Vermeulen, R; Briggs, F; de Bruyn , A G; Conway, J; Moore, C P

    2000-12-25

    We present measurements of absorption by the 21 cm hyperfine transition of neutral hydrogen toward radio sources at substantial look-back times. These data are used in combination with observations of rotational transitions of common interstellar molecules to set limits on the evolution of the fine structure constant: alpha/ alphatheory, the limit on the secular evolution of the scale factor of the compact dimensions, R, is &Rdot/ Rbig bang, of DeltaR /R<10(-5).

  14. Oxide glass structure evolution under swift heavy ion irradiation

    International Nuclear Information System (INIS)

    Mendoza, C.; Peuget, S.; Charpentier, T.; Moskura, M.; Caraballo, R.; Bouty, O.; Mir, A.H.; Monnet, I.; Grygiel, C.; Jegou, C.

    2014-01-01

    Highlights: • Structure of SHI irradiated glass is similar to the one of a hyper quenched glass. • D2 Raman band associated to 3 members ring is only observed in irradiated glass. • Irradiated state seems slightly different to an equilibrated liquid quenched rapidly. - Abstract: The effects of ion tracks on the structure of oxide glasses were examined by irradiating a silica glass and two borosilicate glass specimens containing 3 and 6 oxides with krypton ions (74 MeV) and xenon ions (92 MeV). Structural changes in the glass were observed by Raman and nuclear magnetic resonance spectroscopy using a multinuclear approach ( 11 B, 23 Na, 27 Al and 29 Si). The structure of irradiated silica glass resembles a structure quenched at very high temperature. Both borosilicate glass specimens exhibited depolymerization of the borosilicate network, a lower boron coordination number, and a change in the role of a fraction of the sodium atoms after irradiation, suggesting that the final borosilicate glass structures were quenched from a high temperature state. In addition, a sharp increase in the concentration of three membered silica rings and the presence of large amounts of penta- and hexacoordinate aluminum in the irradiated 6-oxide glass suggest that the irradiated glass is different from a liquid quenched at equilibrium, but it is rather obtained from a nonequilibrium liquid that is partially relaxed by very rapid quenching within the ion tracks

  15. The importance of inherited structures in slope evolution: the Ridnaun Valley case, Italy

    Science.gov (United States)

    Zorzi, L.; Flaim, L.; Massironi, M.; Genevois, R.; Stead, D.

    2013-12-01

    The south facing slope of the Ridnaun Valley (South Tyrol, Italy) comprises the crystalline units belonging to the Austoalpine Nappe of the Alpine orogenic wedge and shows evidence of quaternary gravitational evolution which is highly dependent on the interaction between the slope trend and the brittle/ductile structural setting. The slope valley is incised within the paragneiss rocks of the Oetztal - Stubei Unit and the micaschists of the Schneeberg Unit. These two units are separated by a NNW gentle dipping tectonic contact, which obliquely intersects the E-W slope, and is characterized by multiple ultracataclasitic layers that follow the regional low angle north-dipping schistosity. Folds with sub-horizontal E-trending axes induce a change in the dip direction of the regional schistosity from N dipping (unfavorable to the slip) to SE dipping (favorable to the slip). NNE-SSW and N-S trending faults, having a mean thickness of incoherent fault breccias of 1 m, affect the entire slope. These along with the folds and the ultracataclastic layers, have significant influence on rock mass mechanical properties and on mechanisms and timing of the observed gravitational phenomena. Field work and ALS-HRDEM analysis has revealed different gravitational movements along the slope. A fully evolved gravitational collapse, having the features of a Rock Avalanche (RA), characterizes the central part covering an area of about 2.4 km2; whereas to the east and west of the RA, deep seated gravitational slope deformations (DSGSDs) still affect the slope. An ongoing gravitational deformation is apparent in the uphill sections of the slope, next to the crown area of the RA. PS and DS - SAR interferometry data (provided by the Geological Survey of the Autonomous Province of Bolzano, Italy), testify an ongoing movement on both the DSGSDs bordering the RA, highlighting a most unstable area at the western sector. The heterogeneous behavior of the slope is most likely controlled by the

  16. Microeconomic co-evolution model for financial technical analysis signals

    Science.gov (United States)

    Rotundo, G.; Ausloos, M.

    2007-01-01

    Technical analysis (TA) has been used for a long time before the availability of more sophisticated instruments for financial forecasting in order to suggest decisions on the basis of the occurrence of data patterns. Many mathematical and statistical tools for quantitative analysis of financial markets have experienced a fast and wide growth and have the power for overcoming classical TA methods. This paper aims to give a measure of the reliability of some information used in TA by exploring the probability of their occurrence within a particular microeconomic agent-based model of markets, i.e., the co-evolution Bak-Sneppen model originally invented for describing species population evolutions. After having proved the practical interest of such a model in describing financial index so-called avalanches, in the prebursting bubble time rise, the attention focuses on the occurrence of trend line detection crossing of meaningful barriers, those that give rise to some usual TA strategies. The case of the NASDAQ crash of April 2000 serves as an illustration.

  17. Phylogeny, structure, function, biosynthesis and evolution of sulfated galactose-containing glycans.

    Science.gov (United States)

    Pomin, Vitor H

    2016-03-01

    Glycans are ubiquitous components of all organisms. The specificity of glycan structures works in molecular recognition in multiple biological processes especially cell-cell and cell-matrix signaling events. These events are mostly driven by functional proteins whose activities are ultimately regulated by interactions with carbohydrate moieties of cell surface glycoconjugates. Galactose is a common composing monosaccharide in glycoconjugates. Sulfation at certain positions of the galactose residues does not only increase affinity for some binding proteins but also makes the structures of the controlling glycans more specific to molecular interactions. Here the phylogenetic distribution of glycans containing the sulfated galactose unit is examined across numerous multicellular organisms. Analysis includes autotrophs and heterotrophs from both terrestrial and marine environments. Information exists more regarding the marine species. Although future investigations in molecular biology must be still performed in order to assure certain hypotheses, empirical evidences based on structural biology of the sulfated galactose-containing glycans among different species particularly their backbone and sulfation patterns clearly indicate great specificity in terms of glycosyltransferase and sulfotransferase activity. This set of information suggests that evolution has shaped the biosynthetic machinery of these glycans somewhat related to their potential functions in the organisms. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Soil Retaining Structures : Development of models for structural analysis

    NARCIS (Netherlands)

    Bakker, K.J.

    2000-01-01

    The topic of this thesis is the development of models for the structural analysis of soil retaining structures. The soil retaining structures being looked at are; block revetments, flexible retaining walls and bored tunnels in soft soil. Within this context typical structural behavior of these

  19. Sensitivity Analysis of Viscoelastic Structures

    Directory of Open Access Journals (Sweden)

    A.M.G. de Lima

    2006-01-01

    Full Text Available In the context of control of sound and vibration of mechanical systems, the use of viscoelastic materials has been regarded as a convenient strategy in many types of industrial applications. Numerical models based on finite element discretization have been frequently used in the analysis and design of complex structural systems incorporating viscoelastic materials. Such models must account for the typical dependence of the viscoelastic characteristics on operational and environmental parameters, such as frequency and temperature. In many applications, including optimal design and model updating, sensitivity analysis based on numerical models is a very usefull tool. In this paper, the formulation of first-order sensitivity analysis of complex frequency response functions is developed for plates treated with passive constraining damping layers, considering geometrical characteristics, such as the thicknesses of the multi-layer components, as design variables. Also, the sensitivity of the frequency response functions with respect to temperature is introduced. As an example, response derivatives are calculated for a three-layer sandwich plate and the results obtained are compared with first-order finite-difference approximations.

  20. Structural evolution during fragile-to-strong transition in CuZr(Al) glass-forming liquids

    DEFF Research Database (Denmark)

    Zhou, C.; Hu, L.N.; Sun, Q.J.

    2015-01-01

    In the present work, we show experimental evidence for the dynamic fragile-to-strong (F-S) transition in a series of CuZr(Al) glass-forming liquids (GFLs). A detailed analysis of the dynamics of 98 glass-forming liquids indicates that the F-S transition occurs around Tf-s ≈ 1.36 Tg. Using...... the hyperquenching-annealing-x-ray scattering approach, we have observed a three-stage evolution pattern of medium-range ordering (MRO) structures during the F-S transition, indicating a dramatic change of the MRO clusters around Tf-s upon cooling. The F-S transition in CuZr(Al) GFLs is attributed to the competition...... among the MRO clusters composed of different locally ordering configurations. A phenomenological scenario has been proposed to explain the structural evolution from the fragile to the strong phase in the CuZr(Al) GFLs....

  1. Animal evolution

    DEFF Research Database (Denmark)

    Nielsen, Claus

    This book provides a comprehensive analysis of evolution in the animal kingdom. It reviews the classical, morphological information from structure and embryology, as well as the new data gained from studies using immune stainings of nerves and muscles and blastomere markings, which makes it possi......This book provides a comprehensive analysis of evolution in the animal kingdom. It reviews the classical, morphological information from structure and embryology, as well as the new data gained from studies using immune stainings of nerves and muscles and blastomere markings, which makes...

  2. The ITER thermal shields for the magnet system: Design evolution and analysis

    International Nuclear Information System (INIS)

    Bykov, V.; Krasikov, Yu.; Grigoriev, S.; Komarov, V.; Krylov, V.; Labusov, A.; Pyrjaev, V.; Chiocchio, S.; Smirnov, V.; Sorin, V.; Tanchuk, V.

    2005-01-01

    The thermal shield (TS) system provides the required reduction of thermal loads to the cold structures operating at 4.5 K. This paper presents the rationale for the TS design evolution, details of the recent modifications that affect the TS cooling panels, the central TS ports and support system, interface labyrinths and TS structural joints. The modern results of thermal-hydraulic, thermal, seismic, static and dynamic structural analyses, that involve sub-modeling and sub-structuring finite element analysis techniques, are also reported. The modifications result in considerable reduction of TS mass, surface area and heat loads to/from the TS, simplification of TS assembly procedure and in-cryostat maintenance

  3. Evolution of turbulence structures in a confined square coaxial jet

    International Nuclear Information System (INIS)

    McIlwain, S.; Xu, H.; Khalid, M.

    2003-01-01

    Three turbulence structure identification techniques were used to analyze the flow patterns contained in a large eddy simulation database of a confined square coaxial jet flow. The results obtained using each technique were compared to each other. The traditional method of using contours of vorticity produced the clearest plots that were easy to interpret using physical arguments. No large-scale structures of turbulence were visible in the database. The small-scale structures that did form near the flow inlet along the interface between the inner and annular flows dissipated a short distance downstream; this dissipation was enhanced by the friction between neighbouring pockets of vorticity rotating about different principal coordinates. Once the vorticity was dissipated, the flow behaved in a manner similar to a square duct flow without an inner annular flow. (author)

  4. The Evolution and Structure of Extreme Optical Lightning Flashes.

    Science.gov (United States)

    Peterson, Michael; Rudlosky, Scott; Deierling, Wiebke

    2017-12-27

    This study documents the composition, morphology, and motion of extreme optical lightning flashes observed by the Lightning Imaging Sensor (LIS). The furthest separation of LIS events (groups) in any flash is 135 km (89 km), the flash with the largest footprint had an illuminated area of 10,604 km 2 , and the most dendritic flash has 234 visible branches. The longest-duration convective LIS flash lasted 28 s and is overgrouped and not physical. The longest-duration convective-to-stratiform propagating flash lasted 7.4 s, while the longest-duration entirely stratiform flash lasted 4.3 s. The longest series of nearly consecutive groups in time lasted 242 ms. The most radiant recorded LIS group (i.e., "superbolt") is 735 times more radiant than the average group. Factors that impact these optical measures of flash morphology and evolution are discussed. While it is apparent that LIS can record the horizontal development of the lightning channel in some cases, radiative transfer within the cloud limits the flash extent and level of detail measured from orbit. These analyses nonetheless suggest that lightning imagers such as LIS and Geostationary Lightning Mapper can complement ground-based lightning locating systems for studying physical lightning phenomena across large geospatial domains.

  5. The Evolution and Structure of Extreme Optical Lightning Flashes

    Science.gov (United States)

    Peterson, Michael; Rudlosky, Scott; Deierling, Wiebke

    2017-12-01

    This study documents the composition, morphology, and motion of extreme optical lightning flashes observed by the Lightning Imaging Sensor (LIS). The furthest separation of LIS events (groups) in any flash is 135 km (89 km), the flash with the largest footprint had an illuminated area of 10,604 km2, and the most dendritic flash has 234 visible branches. The longest-duration convective LIS flash lasted 28 s and is overgrouped and not physical. The longest-duration convective-to-stratiform propagating flash lasted 7.4 s, while the longest-duration entirely stratiform flash lasted 4.3 s. The longest series of nearly consecutive groups in time lasted 242 ms. The most radiant recorded LIS group (i.e., "superbolt") is 735 times more radiant than the average group. Factors that impact these optical measures of flash morphology and evolution are discussed. While it is apparent that LIS can record the horizontal development of the lightning channel in some cases, radiative transfer within the cloud limits the flash extent and level of detail measured from orbit. These analyses nonetheless suggest that lightning imagers such as LIS and Geostationary Lightning Mapper can complement ground-based lightning locating systems for studying physical lightning phenomena across large geospatial domains.

  6. Recapitulating the Structural Evolution of Redox Regulation in Adenosine 5′-Phosphosulfate Kinase from Cyanobacteria to Plants*

    Science.gov (United States)

    Herrmann, Jonathan; Nathin, David; Lee, Soon Goo; Sun, Tony; Jez, Joseph M.

    2015-01-01

    In plants, adenosine 5′-phosphosulfate (APS) kinase (APSK) is required for reproductive viability and the production of 3′-phosphoadenosine 5′-phosphosulfate (PAPS) as a sulfur donor in specialized metabolism. Previous studies of the APSK from Arabidopsis thaliana (AtAPSK) identified a regulatory disulfide bond formed between the N-terminal domain (NTD) and a cysteine on the core scaffold. This thiol switch is unique to mosses, gymnosperms, and angiosperms. To understand the structural evolution of redox control of APSK, we investigated the redox-insensitive APSK from the cyanobacterium Synechocystis sp. PCC 6803 (SynAPSK). Crystallographic analysis of SynAPSK in complex with either APS and a non-hydrolyzable ATP analog or APS and sulfate revealed the overall structure of the enzyme, which lacks the NTD found in homologs from mosses and plants. A series of engineered SynAPSK variants reconstructed the structural evolution of the plant APSK. Biochemical analyses of SynAPSK, SynAPSK H23C mutant, SynAPSK fused to the AtAPSK NTD, and the fusion protein with the H23C mutation showed that the addition of the NTD and cysteines recapitulated thiol-based regulation. These results reveal the molecular basis for structural changes leading to the evolution of redox control of APSK in the green lineage from cyanobacteria to plants. PMID:26294763

  7. Large coil test structural analysis

    International Nuclear Information System (INIS)

    Clinard, J.A.; Hammonds, C.J.

    1986-01-01

    The International Fusion Superconducting Magnet Test Facility (IFSMTF) at Oak Ridge National Laboratory (ORNL) is being utilized for testing of 2.5 x 3.5-m bore superconducting 8-T magnets produced by four international agencies (U.S., Euratom, Japan, and Switzerland). The definitive tests in the design configuration, six coils arranged in a compact torus, will begin in late 1985. Partial-array tests involving one US coil and the Japanese coil were completed in the fall of 1984. This presentation describes structural analysis using NASTRAN, with symmetry and superelement techniques, to predict the IFSMTF test stand and coil responses to various combinations of in-plane and out-of-plane loading conditions for both the partial-array and six-coil test configurations. Comparison to partial-array displacement and strain measurements are presented and discussed. Six-coil results and their utilization for determining safe levels of operation of the system are likewise discussed

  8. Microstructural evolution of the LENS manufactured TiAl structure

    CSIR Research Space (South Africa)

    Lengopeng, T

    2016-11-01

    Full Text Available The advent of additive manufacturing presented the new-era where complex structures can be prototype and rapidly manufactured from a computer aided device file. Robust industries such as the aerospace and medicinal require 3 D printed complex...

  9. Structural evolution of ZTA composites during synthesis and processing

    Czech Academy of Sciences Publication Activity Database

    Exare, C.; Kiat, J. M.; Guiblin, N.; Porcher, F.; Petříček, Václav

    2015-01-01

    Roč. 35, č. 4 (2015), s. 1273-1283 ISSN 0955-2219 R&D Projects: GA ČR(CZ) GA14-03276S Institutional support: RVO:68378271 Keywords : ceramic s * alumina–zirconia composites * structural properties * strain effect * size effect Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.933, year: 2015

  10. The evolution of the Russian oil governance structure: A neo-institutionalist interpretation

    International Nuclear Information System (INIS)

    Rossiaud, Sylvain

    2012-01-01

    This PhD dissertation deals with the evolution of the institutional and organizational framework of the Russian oil industry during the period 1992-2012. Its main objective is to characterize and reinterpret the increasing involvement of the national oil companies (NOCs), Rosneft and Gazpromneft, in the upstream activities observed since the middle of the 2000's. Until then, their levels of production had remained very low after the privatization program implemented at the beginning of the transition process. For achieving this objective, we rely on the New Institutional Economics (NIE) theoretical framework. This allows us to lead a comparative analysis of the different oil governance structures, i.e. the alternative modes of organizing the upstream activities. More it enables us to understand the way these different modes interact with the institutional environment of the countries in which they are implemented. We argue that the increasing involvement of the Russian NOCs can be characterized as a change from a liberal oil governance structure to a hybrid oil governance structure. We show that this organizational evolution must be interpreted as the feasible reform that can be implemented by the federal authorities for dealing with the incoherence between the liberal governance structure defined at the beginning of the transition process and the Russian institutional environment. From the beginning of the 1990's until the middle of the 2000's, this institutional incoherence relates to the fact that the Russian institutional environment prevents the effectiveness of oil contracts (licenses, production sharing agreements, tax) governing the transaction between the Russian state and the private oil companies. From the point of view of the federal authorities, two problems appear crucial: their difficulties for capturing the oil rent and the exploration crisis. After the implementation of the hybrid oil governance structure, Rosneft plays a role of

  11. Red Giants as Probes of the Structure and Evolution of the Milky Way

    CERN Document Server

    Montalbán, Josefina; Noels, Arlette

    2012-01-01

    Exciting results are blooming, thanks to a convergence between unprecedented asteroseismic data obtained by the satellites CoRoT and KEPLER, and state-of-the-art models of the internal structure of red giants and of galactic evolution. The pulsation properties now available for thousands of red giants promise to add valuable and independent constraints to current models of structure and evolution of our galaxy. Such a close connection between these domains opens a new very promising gate in our understanding of stars and galaxies. In this book international leaders in the field offer a wide perspective of the recent advancements in: Asteroseismology of red giants Models of the atmosphere, internal structure, and evolution of red giants Stellar population synthesis and models of the Milky Way

  12. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural syst...... systems, it is of interest to investigate how robust the structures are, or what happens if a structural element is added to or removed from the original structure. The present paper discusses this issue for kinetic structures in architecture.......The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural...

  13. The pig X and Y Chromosomes: structure, sequence, and evolution.

    Science.gov (United States)

    Skinner, Benjamin M; Sargent, Carole A; Churcher, Carol; Hunt, Toby; Herrero, Javier; Loveland, Jane E; Dunn, Matt; Louzada, Sandra; Fu, Beiyuan; Chow, William; Gilbert, James; Austin-Guest, Siobhan; Beal, Kathryn; Carvalho-Silva, Denise; Cheng, William; Gordon, Daria; Grafham, Darren; Hardy, Matt; Harley, Jo; Hauser, Heidi; Howden, Philip; Howe, Kerstin; Lachani, Kim; Ellis, Peter J I; Kelly, Daniel; Kerry, Giselle; Kerwin, James; Ng, Bee Ling; Threadgold, Glen; Wileman, Thomas; Wood, Jonathan M D; Yang, Fengtang; Harrow, Jen; Affara, Nabeel A; Tyler-Smith, Chris

    2016-01-01

    We have generated an improved assembly and gene annotation of the pig X Chromosome, and a first draft assembly of the pig Y Chromosome, by sequencing BAC and fosmid clones from Duroc animals and incorporating information from optical mapping and fiber-FISH. The X Chromosome carries 1033 annotated genes, 690 of which are protein coding. Gene order closely matches that found in primates (including humans) and carnivores (including cats and dogs), which is inferred to be ancestral. Nevertheless, several protein-coding genes present on the human X Chromosome were absent from the pig, and 38 pig-specific X-chromosomal genes were annotated, 22 of which were olfactory receptors. The pig Y-specific Chromosome sequence generated here comprises 30 megabases (Mb). A 15-Mb subset of this sequence was assembled, revealing two clusters of male-specific low copy number genes, separated by an ampliconic region including the HSFY gene family, which together make up most of the short arm. Both clusters contain palindromes with high sequence identity, presumably maintained by gene conversion. Many of the ancestral X-related genes previously reported in at least one mammalian Y Chromosome are represented either as active genes or partial sequences. This sequencing project has allowed us to identify genes--both single copy and amplified--on the pig Y Chromosome, to compare the pig X and Y Chromosomes for homologous sequences, and thereby to reveal mechanisms underlying pig X and Y Chromosome evolution. © 2016 Skinner et al.; Published by Cold Spring Harbor Laboratory Press.

  14. Phylogenomic Analysis and Dynamic Evolution of Chloroplast Genomes in Salicaceae

    Directory of Open Access Journals (Sweden)

    Yuan Huang

    2017-06-01

    Full Text Available Chloroplast genomes of plants are highly conserved in both gene order and gene content. Analysis of the whole chloroplast genome is known to provide much more informative DNA sites and thus generates high resolution for plant phylogenies. Here, we report the complete chloroplast genomes of three Salix species in family Salicaceae. Phylogeny of Salicaceae inferred from complete chloroplast genomes is generally consistent with previous studies but resolved with higher statistical support. Incongruences of phylogeny, however, are observed in genus Populus, which most likely results from homoplasy. By comparing three Salix chloroplast genomes with the published chloroplast genomes of other Salicaceae species, we demonstrate that the synteny and length of chloroplast genomes in Salicaceae are highly conserved but experienced dynamic evolution among species. We identify seven positively selected chloroplast genes in Salicaceae, which might be related to the adaptive evolution of Salicaceae species. Comparative chloroplast genome analysis within the family also indicates that some chloroplast genes are lost or became pseudogenes, infer that the chloroplast genes horizontally transferred to the nucleus genome. Based on the complete nucleus genome sequences from two Salicaceae species, we remarkably identify that the entire chloroplast genome is indeed transferred and integrated to the nucleus genome in the individual of the reference genome of P. trichocarpa at least once. This observation, along with presence of the large nuclear plastid DNA (NUPTs and NUPTs-containing multiple chloroplast genes in their original order in the chloroplast genome, favors the DNA-mediated hypothesis of organelle to nucleus DNA transfer. Overall, the phylogenomic analysis using chloroplast complete genomes clearly elucidates the phylogeny of Salicaceae. The identification of positively selected chloroplast genes and dynamic chloroplast-to-nucleus gene transfers in

  15. Floral glands in asclepiads: structure, diversity and evolution

    Directory of Open Access Journals (Sweden)

    Diego Demarco

    Full Text Available ABSTRACT Species of Apocynaceae stand out among angiosperms in having very complex flowers, especially those of asclepiads, which belong to the most derived subfamily (Asclepiadoideae. These flowers are known to represent the highest degree of floral synorganization of the eudicots, and are comparable only to orchids. This morphological complexity may also be understood by observing their glands. Asclepiads have several protective and nuptial secretory structures. Their highly specific and specialized pollination systems are associated with the great diversity of glands found in their flowers. This review gathers data regarding all types of floral glands described for asclepiads and adds three new types (glandular trichome, secretory idioblast and obturator, for a total of 13 types of glands. Some of the species reported here may have dozens of glands of up to 11 types on a single flower, corresponding to the largest diversity of glands recorded to date for a single structure.

  16. Evolution of Tertiary Structure of Viral RNA Dependent Polymerases

    Czech Academy of Sciences Publication Activity Database

    Černý, Jiří; Černá, B.; Valdés, James J.; Grubhoffer, Libor; Růžek, Daniel

    2014-01-01

    Roč. 9, č. 5 (2014), e96070 E-ISSN 1932-6203 R&D Projects: GA ČR GAP502/11/2116; GA ČR GAP302/12/2490; GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 Keywords : Q-BETA replicase * C virus RNA * crystal structure Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2014

  17. The monitoring of air pollution in France. History, evolution, structures

    International Nuclear Information System (INIS)

    Delandre, J.R.

    1991-01-01

    After a broad description of APPA's (Association for Prevention of Atmospheric Pollution) activities in France since it was created in 1958, the structures of the various types of measuring systems (at July 1, 1991) are presented: urban centers networks, industrial areas networks, including forest acid rain monitoring. A list of the main continuously measured pollutants is given (high acidity, settling dust, sulfur dioxide, black smoke, suspended dust, fluorine, etc.)

  18. Regional scale analysis of the altimetric stream network evolution

    Directory of Open Access Journals (Sweden)

    T. Ghizzoni

    2006-01-01

    Full Text Available Floods result from the limited carrying capacity of stream channels when compared to the discharge peak value. The transit of flood waves - with the associated erosion and sedimentation processes - often modifies local stream geometry. In some cases this results in a reduction of the stream carrying capacity, and consequently in an enhancement of the flooding risk. A mathematical model for the prediction of potential altimetric stream network evolution due to erosion and sedimentation processes is here formalized. It works at the regional scale, identifying the tendency of river segments to sedimentation, stability, or erosion. The model builds on geomorphologic concepts, and derives its parameters from extensive surveys. As a case study, tendencies of rivers pertaining to the Valle d'Aosta region are analyzed. Some validation is provided both at regional and local scales of analysis. Local validation is performed both through a mathematical model able to simulate the temporal evolution of the stream profile, and through comparison of the prediction with ante and post-event river surveys, where available. Overall results are strongly encouraging. Possible use of the information derived from the model in the context of flood and landslide hazard mitigation is briefly discussed.

  19. Geodynamic evolution and morphostructural analysis of the Western sector of the Russian Arctic shelf

    Directory of Open Access Journals (Sweden)

    Sorokhtin N. O.

    2016-03-01

    Full Text Available The paper considers issues of the Barents Sea shelf geodynamic evolution and influence of basement geologic structural processes on seabed morphology in their interaction. The obtained data have made possible to assume that the Norwegian-Mezenskaya rift system, Voronin graben, St. Anne and Victoria grabens were formed at the expense of the lithosphere stretching processes, but the Vostochno-Barentsevomorskaya basin and Medvezinsko-Edzinskaya area of depressions developed on the initial stage of lithosphere plate evolution due to collision of several island arcs and now all of them are outliers of the ancient oceanic crust. The technique of morphostructural analysis developed by the authors has allowed solve the inverse problem, and under morphological approach split all largest depressions on two main genetic types that confirm received geodynamic conclusion

  20. Structural evolution of deep-water submarine intraplate volcanoes / Azores

    Science.gov (United States)

    Stakemann, Josefine; Huebscher, Christian; Beier, Christoph; Hildenbrand, Anthony; Nomikou, Paraskevi; Terrinha, Pedro; Weiß, Benedikt

    2017-04-01

    -Atlantic?. EOS, American Geophysical Union. Bibcode: 2009AGUFM.P43B1435D. ISSN 0096-394. Hübscher, C., Ruhnau, M., Nomikou, P., 2015. Volcano-tectonic evolution of the polygenetic Kolumbo submarine volcano / Santorini (Aegean Sea). J. Volcanol. Geotherm. Res. 291, 101-111. Weiß, B., Hübscher, C., Wolf, D., Lüdmann, T., 2015. Submarine explosive volcanism in the southeastern Terceira Rift / São Miguel Region (Azores). J. Volcanol. Geotherm. Res. 303, 79-91.

  1. Thermally induced structural evolution and performance of mesoporous block copolymer-directed alumina perovskite solar cells.

    KAUST Repository

    Tan, Kwan Wee

    2014-04-11

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI(3-x)Cl(x)) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI(3-x)Cl(x) material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance.

  2. Thermally Induced Structural Evolution and Performance of Mesoporous Block Copolymer-Directed Alumina Perovskite Solar Cells

    Science.gov (United States)

    2015-01-01

    Structure control in solution-processed hybrid perovskites is crucial to design and fabricate highly efficient solar cells. Here, we utilize in situ grazing incidence wide-angle X-ray scattering and scanning electron microscopy to investigate the structural evolution and film morphologies of methylammonium lead tri-iodide/chloride (CH3NH3PbI3–xClx) in mesoporous block copolymer derived alumina superstructures during thermal annealing. We show the CH3NH3PbI3–xClx material evolution to be characterized by three distinct structures: a crystalline precursor structure not described previously, a 3D perovskite structure, and a mixture of compounds resulting from degradation. Finally, we demonstrate how understanding the processing parameters provides the foundation needed for optimal perovskite film morphology and coverage, leading to enhanced block copolymer-directed perovskite solar cell performance. PMID:24684494

  3. Structural evolution of Lake Superior I: Western basin

    Energy Technology Data Exchange (ETDEWEB)

    Coakley, B.J.; Wang, H.F. (Univ. of Wisconsin, Madison, WI (United States)); Reynolds, D.J. (Lamont Doherty Geological Observatory, Palisades, NY (United States))

    1992-01-01

    The authors have utilized reflector terminations, reflection character and truncation to interpret a grid of multi-channel seismic reflection profiles collected in the American waters of Lake Superior by Grant-Norpac in 1985. The authors have defined 13 separate reflectors that can be mapped across most of the basin, representing Keweenawan volcanics and sediments of the Jacobsville-Bayfield and Oronto Groups and possibly the early to mid Proterozoic Animikie Group. Structure and isopach maps reveal that the basin is segmented into a series of sub-basins divided by basement highs oblique to the trend of the Lake Superior basin. Unusual is the apparent rarity of extensional structures, which are confined entirely to the extreme western portion of the lake. Reactivation of basin bounding faults as thrusts has been invoked to explain uplift on the Isle Royale and Keweenaw faults. Gravity anomaly data has been interpreted to suggest that the Isle Royal fault is continuous with the Douglas fault in northeastern Wisconsin. The Isle Royale fault terminates west of Isle Royale on the flank of a large basement high. To the west of the termination, deformation is taken up on a blind or intra-stratal thrust which wraps around the basement high. The high is coincident with a distinctive gravity low. It is covered by the sag phase sediments of the Oronto and Jacobsville-Bayfield Groups. The intra-stratal thrust may root below the Keweenawan basalts, suggesting that the basalt section acted as a load bearing member, analogous to carbonate sequences in thrust slices, during the compressional reactivation of the rift structures.

  4. Structural evolution of Lake Superior II: Eastern basin

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, D.J. (Lamont Doherty Geological Observatory, Palisades, NY (United States)); Coakley, B.J.; Wang, H.F. (Univ. of Wisconsin, Madison, WI (United States). Dept. of Geology and Geophysics)

    1992-01-01

    The authors have interpreted 1,400 km of industry and government multichannel seismic reflection data from eastern Lake Superior. Seismic sequences have been identified by using reflection character and reflector terminations and truncations. This framework, coupled with outcrop information, has allowed them to assign lithologic units to some of these reflectors and reconstruct the timing and geometry of structures within the basin. The authors have mapped the Base Jacobsville-Bayfield Group/Top oronto Group, Base oronto Group/Top Keweenawan volcanics, and Basement as well as several reflectors internal to these groups. Integration of gravity and magnetic data with the seismic grid permits regional mapping of faults and folds between seismic lines. In the eastern part of the basin, high-angle basement-involved reverse faults, such as the southeastern combination of the Keweenaw fault, trend NNW-SSE, while broad folds trend E-W. The Keweenaw fault is a complex structural zone and, in the Manitou Island region, steeply-dipping reflectors with abrupt dip reversals indicate a transpressive flower structure. Reactivation of the Keweenaw fault along the southern margin of the basin has rotated and uplifted the basin fill. This region is where the unconformity on top of the Oronto Group is best developed and shows that much of the compressive motion on this fault system occurred post-Oronto and syn-Jacobsville as the top of Jacobsville Group reflector is only slightly deformed. The stratal relationships seen in the seismic data suggest that compressive deformation was synchronous with Oronto and early Jacobsville deposition.

  5. Review: Evolution of GnIH structure and function

    Directory of Open Access Journals (Sweden)

    Tomohiro eOsugi

    2014-08-01

    Full Text Available Discovery of gonadotropin-inhibitory hormone (GnIH in the Japanese quail in 2000 was the first to demonstrate the existence of a hypothalamic neuropeptide inhibiting gonadotropin release. We now know that GnIH regulates reproduction by inhibiting gonadotropin synthesis and release via action on the gonadotropin-releasing hormone (GnRH system and the gonadotrope in various vertebrates. GnIH peptides identified in birds and mammals have a common LPXRF-amide (X = L or Q motif at the C-terminus and inhibits pituitary gonadotropin secretion. However, the function and structure of GnIH peptides were diverse in fish. Goldfish GnIHs possessing a C-terminal LPXRF-amide motif had both stimulatory and inhibitory effects on gonadotropin synthesis or release. The C-terminal sequence of grass puffer and medaka GnIHs were MPQRF-amide. To investigate the evolutionary origin of GnIH and its ancestral structure and function, we searched for GnIH in agnathans, the most ancient lineage of vertebrates. We identified GnIH precursor gene and mature GnIH peptides with C-terminal QPQRF-amide or RPQRF-amide from the brain of sea lamprey. Lamprey GnIH fibers were in close proximity to GnRH-III neurons. Further, one of lamprey GnIHs stimulated the expression of lamprey GnRH-III peptide in the hypothalamus and gonadotropic hormone β mRNA expression in the pituitary. We further identified the ancestral form of GnIH, which had a C-terminal RPQRF-amide, and its receptors in amphioxus, the most basal chordate species. The amphioxus GnIH inhibited cAMP signaling in vitro. In sum, the original forms of GnIH may date back to the time of the emergence of early chordates. GnIH peptides may have had various C-terminal structures slightly different from LPXRF-amide in basal chordates, which had stimulatory and/or inhibitory functions on reproduction. The C-terminal LPXRF-amide structure and its inhibitory function on reproduction may be selected in later-evolved vertebrates, such as

  6. Structural Evolution and Mechanisms of Fatigue in Polycrystalline Brass

    DEFF Research Database (Denmark)

    Carstensen, Jesper Vejlø

    system for the industrially important austenitic steels. A quantitative fatigue damage characterization has been carried out using a classification of sur-face cracks based on their length and growth behaviour. This has provided the basis for using a numerical Monte Carlo type model, which has been...... planar and wavy slip. The mechanical and structural behaviour observed in brass resembles recent observations in 316L austenitic stainless steels, and the present results reveal that Cu-30%Zn and 316L have approximately the same fatigue life curve. This empha-sizes brass as being a convenient model...

  7. Structural evolution and diversity of the caterpillar trunk

    DEFF Research Database (Denmark)

    Dupont, Steen Thorleif

    feeding and climbing behavior (MS1), 3) describe the micropterigid and agathiphagid trunk morphology, including secondary locomotory structures, chaetotaxy, trunk musculature, and in the case of the former also the unique cuticle. The purpose of these descriptions is to focus on the seemingly aberrant...... cuticle thickness, the degree of myrmecopily and the underlying mechanism of lycaenid-ant associations (MS4). In two major manuscripts (MS1-2), comparative descriptions are provided of the larval trunk in, respectively the Micropterigidae and the lowest-grade leaf-mining caterpillars. Available knowledge...

  8. Urban slum structure: integrating socioeconomic and land cover data to model slum evolution in Salvador, Brazil.

    Science.gov (United States)

    Hacker, Kathryn P; Seto, Karen C; Costa, Federico; Corburn, Jason; Reis, Mitermayer G; Ko, Albert I; Diuk-Wasser, Maria A

    2013-10-20

    The expansion of urban slums is a key challenge for public and social policy in the 21st century. The heterogeneous and dynamic nature of slum communities limits the use of rigid slum definitions. A systematic and flexible approach to characterize, delineate and model urban slum structure at an operational resolution is essential to plan, deploy, and monitor interventions at the local and national level. We modeled the multi-dimensional structure of urban slums in the city of Salvador, a city of 3 million inhabitants in Brazil, by integrating census-derived socioeconomic variables and remotely-sensed land cover variables. We assessed the correlation between the two sets of variables using canonical correlation analysis, identified land cover proxies for the socioeconomic variables, and produced an integrated map of deprivation in Salvador at 30 m × 30 m resolution. The canonical analysis identified three significant ordination axes that described the structure of Salvador census tracts according to land cover and socioeconomic features. The first canonical axis captured a gradient from crowded, low-income communities with corrugated roof housing to higher-income communities. The second canonical axis discriminated among socioeconomic variables characterizing the most marginalized census tracts, those without access to sanitation or piped water. The third canonical axis accounted for the least amount of variation, but discriminated between high-income areas with white-painted or tiled roofs from lower-income areas. Our approach captures the socioeconomic and land cover heterogeneity within and between slum settlements and identifies the most marginalized communities in a large, complex urban setting. These findings indicate that changes in the canonical scores for slum areas can be used to track their evolution and to monitor the impact of development programs such as slum upgrading.

  9. Structure and evolution of protein interaction networks: a statistical model for link dynamics and gene duplications

    Directory of Open Access Journals (Sweden)

    Wagner Andreas

    2004-11-01

    Full Text Available Abstract Background The structure of molecular networks derives from dynamical processes on evolutionary time scales. For protein interaction networks, global statistical features of their structure can now be inferred consistently from several large-throughput datasets. Understanding the underlying evolutionary dynamics is crucial for discerning random parts of the network from biologically important properties shaped by natural selection. Results We present a detailed statistical analysis of the protein interactions in Saccharomyces cerevisiae based on several large-throughput datasets. Protein pairs resulting from gene duplications are used as tracers into the evolutionary past of the network. From this analysis, we infer rate estimates for two key evolutionary processes shaping the network: (i gene duplications and (ii gain and loss of interactions through mutations in existing proteins, which are referred to as link dynamics. Importantly, the link dynamics is asymmetric, i.e., the evolutionary steps are mutations in just one of the binding parters. The link turnover is shown to be much faster than gene duplications. Both processes are assembled into an empirically grounded, quantitative model for the evolution of protein interaction networks. Conclusions According to this model, the link dynamics is the dominant evolutionary force shaping the statistical structure of the network, while the slower gene duplication dynamics mainly affects its size. Specifically, the model predicts (i a broad distribution of the connectivities (i.e., the number of binding partners of a protein and (ii correlations between the connectivities of interacting proteins, a specific consequence of the asymmetry of the link dynamics. Both features have been observed in the protein interaction network of S. cerevisiae.

  10. Risk Analysis of Marine Structures

    DEFF Research Database (Denmark)

    Hansen, Peter Friis

    1998-01-01

    Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated.......Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated....

  11. Evolution Dynamics of Relief and Sediment Structures During the Initial Phase of Ecosystem Evolution Within an Experimentally Constructed Catchment Landscape and Their Influence on the Shallow Subsurface

    Science.gov (United States)

    Huerkamp, K.; Voelkel, J.; Leopold, M.; Roeder, J.; Winkelbauer, J.

    2008-12-01

    The studies are integrated in a project of the Collaborative Research Center of the German Research Foundation (DFG SFB-TRR 38) 'Structures and processes of the initial ecosystem development phase in an artificial water catchment'. The experimental catchment 'Hühnerwasser' is built up by mechanically deposited sediments reconstructing an initially emerged landscape. In order to monitor its geomorphological as well as ecofunctional evolution with time it is essential to incorporate comprehensive geophysical applications dealing with geomorphology and sedimentology of both surface as well as shallow subsurface. Digital terrain modelling on meso- to microscale is employed to reflect and analyze superficial processes and evolution trends as well as their influence on the abiotic and biotic structures and processes of the succeeding ecosystem. Especially in the case of the portrayal and analysis of subsurface characteristics, strategy needs to adapt to the special requirements of the SFB-project as the catchment system should only underlie 'natural' conditions and therefore not be altered by any implementations in the course of field investigation. Consequently, intrusive methods such as drillings or profiles are to be omitted. Methods of geophysical prospection hence constitute an indispensable tool in investigation of subsurface composition. Ground penetrating radar (GPR) and electric resistivity tomography (ERT) are applied with adequate resolution to detect the primary deposition structures within the technogenically bedded sediment. By means of this evaluation subsurface structures can be interpreted with regards to their relevance in controlling soil water movement, slope hydrology, redox interactions, root distribution etc. Furthermore, alterations of these primary structures resulting from bio- and pedoturbation processes can be monitored.

  12. Structure and function evolution of thiolate monolayers on gold

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Grant Alvin [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    The use of n-alkanethiolate self-assembled monolayers on gold has blossomed in the past few years. These systems have functioned as models for common interfaces. Thiolate monolayers are ideal because they are easily modified before or after deposition. The works contained within this dissertation include interfacial characterization (infrared reflection absorption spectroscopy, ellipsometry, contact angle, scanning probe microscopy, and heterogeneous electron-transfer kinetics) and various modeling scenarios. The results of these characterizations present ground-breaking insights into the structure, function, and reproducible preparation of these monolayers. Surprisingly, three interfacial properties (electron-transfer, contact angle, and ellipsometry) were discovered to depend directly on the odd-even character of the monolayer components. Molecular modeling was utilized to investigate adlayer orientation, and suggests that these effects are adlayer structure specific. Finally, the electric force microscopy and theoretical modeling investigations of monolayer samples are presented, which show that the film dielectric constant, thickness, and dipole moment directly affect image contrast. In addition, the prospects for utilization of this emerging technique are outlined.

  13. Structure and Function Evolution of Thiolate Monolayers on Gold

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Grant Alvin [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    The use of n-alkanethiolate self-assembled monolayers on gold has blossomed in the past few years. These systems have functioned as models for common interfaces. Thiolate monolayers are ideal because they are easily modified before or after deposition. The works contained within this dissertation include interfacial characterization (inbred reflection absorption spectroscopy, ellipsometry, contact angle, scanning probe microscopy, and heterogeneous electron-transfer kinetics) and various modeling scenarios. The results of these characterizations present ground-breaking insights into the structure, function, and reproducible preparation of these monolayers. Surprisingly, three interfacial properties (electron-transfer, contact angle, and ellipsometry) were discovered to depend directly on the odd-even character of the monolayer components. Molecular modeling was utilized to investigate adlayer orientation, and suggests that these effects are adlayer structure specific. Finally, the electric force microscopy and theoretical modeling investigations of monolayer samples are presented, which show that the film dielectric constant, thickness, and dipole moment directly affect image contrast. In addition, the prospects for utilization of this emerging technique are outlined.

  14. Nanoscale structural oscillations in perovskite oxides induced by oxygen evolution

    Science.gov (United States)

    Han, Binghong; Stoerzinger, Kelsey A.; Tileli, Vasiliki; Gamalski, Andrew D.; Stach, Eric A.; Shao-Horn, Yang

    2017-01-01

    Understanding the interaction between water and oxides is critical for many technological applications, including energy storage, surface wetting/self-cleaning, photocatalysis and sensors. Here, we report observations of strong structural oscillations of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) in the presence of both H2O vapour and electron irradiation using environmental transmission electron microscopy. These oscillations are related to the formation and collapse of gaseous bubbles. Electron energy-loss spectroscopy provides direct evidence of O2 formation in these bubbles due to the incorporation of H2O into BSCF. SrCoO3-δ was found to exhibit small oscillations, while none were observed for La0.5Sr0.5CoO3-δ and LaCoO3. The structural oscillations of BSCF can be attributed to the fact that its oxygen 2p-band centre is close to the Fermi level, which leads to a low energy penalty for oxygen vacancy formation, high ion mobility, and high water uptake. This work provides surprising insights into the interaction between water and oxides under electron-beam irradiation.

  15. Influence of electron irradiation on internal friction and structure evolution of polymer composites

    International Nuclear Information System (INIS)

    Ismailova, G.A.

    2007-01-01

    Full text: Important qualitative information on structural evolution and radiation alterations in polymer materials under the action of ionizing radiation can be obtained from the analysis of the temperature dependences of internal friction. Changing of internal friction parameters of relax maxima during irradiation is qualitative degree parameter of radiation scission-cross linking of the polymer molecules. In this work, the general phenomenological approach is realized by introduction of the effective 'observed' parameters into the simple kinetic equations. The applicability of such approach is justified by the fact that kinetics of both internal friction and scission-cross linking processes can be characterized by the same effective parameters. Temperature dependences of internal friction are experimentally studied in epoxy irradiated by 2.5 MeV pulse electron beam to different doses (D=3 MGy, 6 MGy and 9 MGy). Time dependences of internal friction characteristics associated with radiation-induced processes of polymer scission and cross-linking are analyzed and discussed. Experimental data on kinetics of structural transformations in epoxy are interpreted on the base of analytical solutions of differential equations for free radical accumulation during and after irradiation subject to the arbitrary effective order of radical recombination. It is shown that in the range of doses and dose rates under study radiation-induced scission predominates during polymer irradiation but in a certain period of time after irradiation scission changes to cross-linking. Characteristics of the kinetic curves obtained essentially depend on the dose

  16. Evolution in the enunciative structure of the political discourse

    Directory of Open Access Journals (Sweden)

    Joanna Jereczek-Lipińska

    2012-01-01

    Full Text Available This study is based upon discursive and logometric analysis of the political speeches delivered by the candidates during the campaign and pre-campaign phases of the 2012 presidential elections in France, taking into account the results of previous studies related to the 2007 presidential elections. The present paper aims at tracing the different representations of the speaker within his own speeches and at analyzing the way he verbalizes himself in his campaign by observing the use, the distribution, the role and the possible impact of “I” and of the other personal pronouns within the frame of political communication. The analysis of statistical data tends to emphasize syntactic as well as morphological, stylistic, lexical, and gramatical distinctive features of the speeches delivered by the candidates to the presidential elections, especially in relation with the new possibilities conveyed by internet.

  17. Economic Evolution and Structural Adjustment: Proceedings, Berkeley, California, USA, 1985

    OpenAIRE

    Batten, D.F.; Casti, J.L.; Johansson, B.

    1987-01-01

    Since the beginning of the fifties, the ruling paradigm in the discipline of economics has been that of a competitive general equilibrium. Associated dynamic analyses have therefore been preoccupied with the stability of this equilibrium state, corresponding simply to studies of comparative statics. The need to permeate the boundaries of this paradigm in order to open up new pathways for genuine dynamic analysis is now pressing. The contributions contained in this volume spring from this...

  18. Comparative empirical analysis of flow-weighted transit route networks in R-space and evolution modeling

    Science.gov (United States)

    Huang, Ailing; Zang, Guangzhi; He, Zhengbing; Guan, Wei

    2017-05-01

    Urban public transit system is a typical mixed complex network with dynamic flow, and its evolution should be a process coupling topological structure with flow dynamics, which has received little attention. This paper presents the R-space to make a comparative empirical analysis on Beijing’s flow-weighted transit route network (TRN) and we found that both the Beijing’s TRNs in the year of 2011 and 2015 exhibit the scale-free properties. As such, we propose an evolution model driven by flow to simulate the development of TRNs with consideration of the passengers’ dynamical behaviors triggered by topological change. The model simulates that the evolution of TRN is an iterative process. At each time step, a certain number of new routes are generated driven by travel demands, which leads to dynamical evolution of new routes’ flow and triggers perturbation in nearby routes that will further impact the next round of opening new routes. We present the theoretical analysis based on the mean-field theory, as well as the numerical simulation for this model. The results obtained agree well with our empirical analysis results, which indicate that our model can simulate the TRN evolution with scale-free properties for distributions of node’s strength and degree. The purpose of this paper is to illustrate the global evolutional mechanism of transit network that will be used to exploit planning and design strategies for real TRNs.

  19. Evolution and structural organization of the C proteins of paramyxovirinae.

    Directory of Open Access Journals (Sweden)

    Michael K Lo

    Full Text Available The phosphoprotein (P gene of most Paramyxovirinae encodes several proteins in overlapping frames: P and V, which share a common N-terminus (PNT, and C, which overlaps PNT. Overlapping genes are of particular interest because they encode proteins originated de novo, some of which have unknown structural folds, challenging the notion that nature utilizes only a limited, well-mapped area of fold space. The C proteins cluster in three groups, comprising measles, Nipah, and Sendai virus. We predicted that all C proteins have a similar organization: a variable, disordered N-terminus and a conserved, α-helical C-terminus. We confirmed this predicted organization by biophysically characterizing recombinant C proteins from Tupaia paramyxovirus (measles group and human parainfluenza virus 1 (Sendai group. We also found that the C of the measles and Nipah groups have statistically significant sequence similarity, indicating a common origin. Although the C of the Sendai group lack sequence similarity with them, we speculate that they also have a common origin, given their similar genomic location and structural organization. Since C is dispensable for viral replication, unlike PNT, we hypothesize that C may have originated de novo by overprinting PNT in the ancestor of Paramyxovirinae. Intriguingly, in measles virus and Nipah virus, PNT encodes STAT1-binding sites that overlap different regions of the C-terminus of C, indicating they have probably originated independently. This arrangement, in which the same genetic region encodes simultaneously a crucial functional motif (a STAT1-binding site and a highly constrained region (the C-terminus of C, seems paradoxical, since it should severely reduce the ability of the virus to adapt. The fact that it originated twice suggests that it must be balanced by an evolutionary advantage, perhaps from reducing the size of the genetic region vulnerable to mutations.

  20. MUFOLD-DB: a processed protein structure database for protein structure prediction and analysis.

    Science.gov (United States)

    He, Zhiquan; Zhang, Chao; Xu, Yang; Zeng, Shuai; Zhang, Jingfen; Xu, Dong

    2014-01-01

    Protein structure data in Protein Data Bank (PDB) are widely used in studies of protein function and evolution and in protein structure prediction. However, there are two main barriers in large-scale usage of PDB data: 1) PDB data are highly redundant in terms of sequence and structure similarity; and 2) many PDB files have issues due to inconsistency of data and standards as well as missing residues, so that automated retrieval and analysis are often difficult. To address these issues, we have created MUFOLD-DB http://mufold.org/mufolddb.php, a web-based database, to collect and process the weekly PDB files thereby providing users with non-redundant, cleaned and partially-predicted structure data. For each of the non-redundant sequences, we annotate the SCOP domain classification and predict structures of missing regions by loop modelling. In addition, evolutional information, secondary structure, disorder region, and processed three-dimensional structure are computed and visualized to help users better understand the protein. MUFOLD-DB integrates processed PDB sequence and structure data and multiple computational results, provides a friendly interface for users to retrieve, browse and download these data, and offers several useful functionalities to facilitate users' data operation.

  1. Modeling high temperature materials behavior for structural analysis

    CERN Document Server

    Naumenko, Konstantin

    2016-01-01

    This monograph presents approaches to characterize inelastic behavior of materials and structures at high temperature. Starting from experimental observations, it discusses basic features of inelastic phenomena including creep, plasticity, relaxation, low cycle and thermal fatigue. The authors formulate constitutive equations to describe the inelastic response for the given states of stress and microstructure. They introduce evolution equations to capture hardening, recovery, softening, ageing and damage processes. Principles of continuum mechanics and thermodynamics are presented to provide a framework for the modeling materials behavior with the aim of structural analysis of high-temperature engineering components.

  2. Shallow nitrogen ion implantation: Evolution of chemical state and defect structure in titanium

    Energy Technology Data Exchange (ETDEWEB)

    Manojkumar, P.A., E-mail: manoj@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Chirayath, V.A.; Balamurugan, A.K.; Krishna, Nanda Gopala; Ilango, S.; Kamruddin, M.; Amarendra, G.; Tyagi, A.K. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Raj, Baldev [National Institute of Advanced Studies, Bangalore 560 012 (India)

    2016-09-15

    Highlights: • Low energy nitrogen ion implantation in titanium was studied. • Chemical and defect states were analyzed using SIMS, XPS and PAS. • SIMS and depth resolved XPS data showed good agreement. • Depth resolved defect and chemical states information were revealed. • Formation of 3 layers of defect states proposed to fit PAS results. - Abstract: Evolution of chemical states and defect structure in titanium during low energy nitrogen ion implantation by Plasma Immersion Ion Implantation (PIII) process is studied. The underlying process of chemical state evolution is investigated using secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The implantation induced defect structure evolution as a function of dose is elucidated using variable energy positron annihilation Doppler broadening spectroscopy (PAS) and the results were corroborated with chemical state. Formation of 3 layers of defect state was modeled to fit PAS results.

  3. Small RNA-regulated networks and the evolution of novel structures in plants.

    Science.gov (United States)

    Plavskin, Y; Timmermans, M C P

    2012-01-01

    The evolution of plants on land has produced a great diversity of organs, tissues, and cell types. Many of the genes identified as having a role in the development of such structures in flowering plants are conserved across all land plants, including in clades that diverged before the evolution of the structure in question. This suggests that novel organs commonly evolve via the cooption of existing developmental gene regulatory networks (GRNs). Although numerous examples of such cooptions have been identified, little is known about why those specific GRNs have been coopted. In this review, we discuss the properties of GRNs that may favor their cooption, as well as the mechanisms by which this can occur, in the context of plant developmental evolution. We especially focus on small RNA (sRNA)-regulated and auxin-signaling GRNs as intriguing models of regulatory network recruitment.

  4. Evolution of climatic niche specialization: a phylogenetic analysis in amphibians.

    Science.gov (United States)

    Bonetti, Maria Fernanda; Wiens, John J

    2014-11-22

    The evolution of climatic niche specialization has important implications for many topics in ecology, evolution and conservation. The climatic niche reflects the set of temperature and precipitation conditions where a species can occur. Thus, specialization to a limited set of climatic conditions can be important for understanding patterns of biogeography, species richness, community structure, allopatric speciation, spread of invasive species and responses to climate change. Nevertheless, the factors that determine climatic niche width (level of specialization) remain poorly explored. Here, we test whether species that occur in more extreme climates are more highly specialized for those conditions, and whether there are trade-offs between niche widths on different climatic niche axes (e.g. do species that tolerate a broad range of temperatures tolerate only a limited range of precipitation regimes?). We test these hypotheses in amphibians, using phylogenetic comparative methods and global-scale datasets, including 2712 species with both climatic and phylogenetic data. Our results do not support either hypothesis. Rather than finding narrower niches in more extreme environments, niches tend to be narrower on one end of a climatic gradient but wider on the other. We also find that temperature and precipitation niche breadths are positively related, rather than showing trade-offs. Finally, our results suggest that most amphibian species occur in relatively warm and dry environments and have relatively narrow climatic niche widths on both of these axes. Thus, they may be especially imperilled by anthropogenic climate change. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  5. Rifting to India-Asia Reactivation: Multi-phase Structural Evolution of the Barmer Basin, Rajasthan, northwest India

    Science.gov (United States)

    Kelly, M. J.; Bladon, A.; Clarke, S.; Najman, Y.; Copley, A.; Kloppenburg, A.

    2015-12-01

    The Barmer Basin, situated within the West Indian Rift System, is an intra-cratonic rift basin produced during Gondwana break-up. Despite being a prominent oil and gas province, the structural evolution and context of the rift within northwest India remains poorly understood. Substantial subsurface datasets acquired during hydrocarbon exploration provide an unrivalled tool to investigate the tectonic evolution of the Barmer Basin rift and northwest India during India-Asia collision. Here we present a structural analysis using seismic datasets to investigate Barmer Basin evolution and place findings within the context of northwest India development. Present day rift structural architectures result from superposition of two non-coaxial extensional events; an early mid-Cretaceous rift-oblique event (NW-SE), followed by a main Paleocene rifting phase (NE-SW). Three phases of fault reactivation follow rifting: A transpressive, Late Paleocene inversion along localised E-W and NNE-SSW-trending faults; a widespread Late Paleocene-Early Eocene inversion and Late Miocene-Present Day transpressive strike-slip faulting along NW-SE-trending faults and isolated inversion structures. A major Late Eocene-Miocene unconformity in the basin is also identified, approximately coeval with those identified within the Himalayan foreland basin, suggesting a common cause related to India-Asia collision, and calling into question previous explanations that are not compatible with spatial extension of the unconformity beyond the foreland basin. Although, relatively poorly age constrained, extensional and compressional events within the Barmer Basin can be correlated with regional tectonic processes including the fragmentation of Gondwana, the rapid migration of the Greater Indian continent, to subsequent collision with Asia. New insights into the Barmer Basin development have important implications not only for ongoing hydrocarbon exploration but the temporal evolution of northwest India.

  6. Experimental study on evolution of bed structures of natural mountain rivers

    Directory of Open Access Journals (Sweden)

    Huai-xiang Liu

    2011-06-01

    Full Text Available Bed structures in many mountain rivers provide additional resistance to the flow. A field experiment was conducted on debris flow deposits in the valley of the Jiangjiagou Ravine, a tributary of the Yangtze River in southwestern China, to study the evolution and distribution of bed structures and their relationship with environmental conditions. Water and sediment from the Jiangjiagou main stream were diverted into the experimental channel. Several hydrological schemes were adopted to scour the channel until equilibrium was reached. During this process the evolutions of bed structures and channel configuration were investigated. The results indicate that stronger bed structures mean greater stream power consumption, greater resistance, and greater slope in a certain section when rivers are in dynamic equilibrium. Thus, to some extent the longitudinal profiles of channels can be determined by the distribution of bed structures. In natural cases, the strength and evolution of bed structures are under the influence of environmental conditions such as discharge and bed-load transportation rate. That is, given the same conditions, the same bed structure distribution and longitudinal profile can be predicted.

  7. Structure and Evolution of the Central Andes of Peru

    Science.gov (United States)

    Gonzalez, L.; Pfiffner, O. A.

    2009-04-01

    part of the Western Cordillera, near Huaraz, a vertical fault puts a Late Miocene to Early Pliocene batholith (Cordillera Blanca) in direct contact to Miocene volcanics (Calipuy group, Cordillera Negra). The structure of the Central Highlands is characterized by relatively open folds in the Paleozoic to Mesozoic strata. Overlying Quaternary deposits are tilted and locally even folded. Eocene to Miocene undeformed granitoids intrude these structures. A swarm of NNW-SSE striking and steeply dipping faults separate the Eastern Cordillera from the Highlands. Some of these faults suggest block faulting. However, near Huancayo a clear indication of strike-slip motion could be found. The Neoproterozoic basement rocks and the Early Paleozoic sediments are unconformably overlain by Late Paleozoic sediments which in turn are folded. Within the Subandine zone, the structural style is characterized by east directed imbricate thrusting. The thrust faults cut down into the crystalline basement going west, suggesting a detachment within upper crustal crystalline basement rocks. In the Central Peruvian Andes, compressional deformation events progressed from west to east. Early Cretaceous plutons of the coast batholith intruded folded Jurassic to Early Cretaceous volcaniclastic rocks of the Casma group and suggest an Early Cretaceous phase of shortening in the Pacific coastal area of the Western Cordillera (referred to as Mochica phase in the literature). Within the Western Cordillera, a major phase of pre-Eocene erosion removed a substantial amount of the tight upright folds. The youngest strata folded are of Late Cretaceous to Early Paleocene age (Red Beds). The overlying volcanics are slightly younger (middle Eocene) and bracket the tight folding, referred to as Inca phase, to Late Paleocene to Early Eocene times. This is corroborated by Eocene to Miocene granitic intrusions in the adjacent fold-and-thrust belt. Still younger deformations, referred to as Quechua Phase, produced

  8. Stable isotope analysis of precipitation samples obtained via crowdsourcing reveals the spatiotemporal evolution of Superstorm Sandy.

    Directory of Open Access Journals (Sweden)

    Stephen P Good

    Full Text Available Extra-tropical cyclones, such as 2012 Superstorm Sandy, pose a significant climatic threat to the northeastern United Sates, yet prediction of hydrologic and thermodynamic processes within such systems is complicated by their interaction with mid-latitude water patterns as they move poleward. Fortunately, the evolution of these systems is also recorded in the stable isotope ratios of storm-associated precipitation and water vapor, and isotopic analysis provides constraints on difficult-to-observe cyclone dynamics. During Superstorm Sandy, a unique crowdsourced approach enabled 685 precipitation samples to be obtained for oxygen and hydrogen isotopic analysis, constituting the largest isotopic sampling of a synoptic-scale system to date. Isotopically, these waters span an enormous range of values (> 21‰ for δ(18O, > 160‰ for δ(2H and exhibit strong spatiotemporal structure. Low isotope ratios occurred predominantly in the west and south quadrants of the storm, indicating robust isotopic distillation that tracked the intensity of the storm's warm core. Elevated values of deuterium-excess (> 25‰ were found primarily in the New England region after Sandy made landfall. Isotope mass balance calculations and Lagrangian back-trajectory analysis suggest that these samples reflect the moistening of dry continental air entrained from a mid-latitude trough. These results demonstrate the power of rapid-response isotope monitoring to elucidate the structure and dynamics of water cycling within synoptic-scale systems and improve our understanding of storm evolution, hydroclimatological impacts, and paleo-storm proxies.

  9. Stable isotope analysis of precipitation samples obtained via crowdsourcing reveals the spatiotemporal evolution of Superstorm Sandy.

    Science.gov (United States)

    Good, Stephen P; Mallia, Derek V; Lin, John C; Bowen, Gabriel J

    2014-01-01

    Extra-tropical cyclones, such as 2012 Superstorm Sandy, pose a significant climatic threat to the northeastern United Sates, yet prediction of hydrologic and thermodynamic processes within such systems is complicated by their interaction with mid-latitude water patterns as they move poleward. Fortunately, the evolution of these systems is also recorded in the stable isotope ratios of storm-associated precipitation and water vapor, and isotopic analysis provides constraints on difficult-to-observe cyclone dynamics. During Superstorm Sandy, a unique crowdsourced approach enabled 685 precipitation samples to be obtained for oxygen and hydrogen isotopic analysis, constituting the largest isotopic sampling of a synoptic-scale system to date. Isotopically, these waters span an enormous range of values (> 21‰ for δ(18)O, > 160‰ for δ(2)H) and exhibit strong spatiotemporal structure. Low isotope ratios occurred predominantly in the west and south quadrants of the storm, indicating robust isotopic distillation that tracked the intensity of the storm's warm core. Elevated values of deuterium-excess (> 25‰) were found primarily in the New England region after Sandy made landfall. Isotope mass balance calculations and Lagrangian back-trajectory analysis suggest that these samples reflect the moistening of dry continental air entrained from a mid-latitude trough. These results demonstrate the power of rapid-response isotope monitoring to elucidate the structure and dynamics of water cycling within synoptic-scale systems and improve our understanding of storm evolution, hydroclimatological impacts, and paleo-storm proxies.

  10. The evolution of the human mind and logic--mathematics structures.

    Science.gov (United States)

    Yunes, Rosendo A

    2005-09-07

    The evolution of the human mind is discussed based on: (i) the fact that living beings interchange matter, energy and information with their environment, (ii) an ontological interpretation of the "reality" of the quantum world, of which logic-mathematics structures are considered constitutive parts, (iii) recent theories according to which living beings are considered as dynamic complex systems organized by information, and (iv) the fact that the evolution of living beings is guided by information about the environment and by intrinsic information on living systems (auto-organization). Assuming the evolution of vision as a model we observe that the driving forces that directed the evolution of the eyes, as dynamic complex systems, are the information about the environment supplied by sunlight and the intrinsic information-gaining mechanism of living organisms. Thus, there exists a convergence toward a visual system with the greatest ability to obtain light information, like the human eye, and also a divergence that leads to the development of specific qualities in some species. As in the case of vision the evolution of the human mind-brain cannot be a consequence of factors unrelated to the object of its own functioning. The human mind was structured for the acquisition from reality of the logic-mathematics structures that underlie the whole universe and consequently of an internal representation of the external world and of its own self. Thus, these structures are, together with the intrinsic capacity for auto-organization of the human brain, the predominant driving force of the human mind evolution. Both factors are complementary.

  11. Safety analysis of an ancient iron structure

    International Nuclear Information System (INIS)

    Kweon, Young Gak; Yoon, Byeng Hyun; Lim, Jae Kyun; Lee, Sung Bum

    2002-01-01

    Safety analysis of an ancient iron structure, Danggan, constructed over than a thousand years ago was performed. The structure is consisted of 24 iron cylinders of which the total height is about 15.4 m. The analysis was done by the ultrasonic test to measure thickness of each cylinder, the radiographic test to investigate the inside of cylinders, the measurement of inclination of the structure and the structural analysis to estimate the stress level applied by the wind. Results showed that Danggan structure was on state being well safe at present, but it could be dangerous when the inclination of the structure becomes severely progressive.

  12. RNA structural constraints in the evolution of the influenza A virus genome NP segment

    NARCIS (Netherlands)

    A.P. Gultyaev (Alexander); A. Tsyganov-Bodounov (Anton); M.I. Spronken (Monique); S. Van Der Kooij (Sander); R.A.M. Fouchier (Ron); R.C.L. Olsthoorn (René)

    2014-01-01

    textabstractConserved RNA secondary structures were predicted in the nucleoprotein (NP) segment of the influenza A virus genome using comparative sequence and structure analysis. A number of structural elements exhibiting nucleotide covariations were identified over the whole segment length,

  13. Surnames and dialects in France: population structure and cultural evolution.

    Science.gov (United States)

    Scapoli, C; Goebl, H; Sobota, S; Mamolini, E; Rodriguez-Larralde, A; Barrai, I

    2005-11-07

    To study the isonymy structure of France as related to local language variations, the surname distributions of 6.03 million telephone users registered for the year 2002 were analysed in the 21 conterminous regions, their 94 departments and in 809 towns of the Country. For regions and departments the differences among local dialects were quantified according to the dialecto-metrization of the Atlas Linguistique Français. We found that Lasker's distance between regions was correlated with geographic distance with r=0.692+/-0.040, while Euclidean (r=0.546+/-0.058) and Nei's (r=0.610+/-0.048) distances were less correlated. Slightly lower correlations were observed for departments. Also, dialectometric distance was correlated with geography (r=0.582+/-0.069 for regions and r=0.617+/-0.015 for departments). The correlations between Lasker and dialectometric matrix distances for regions and departments are r=0.625+/-0.046 and 0.544+/-0.014, respectively, indicating that the common cause generating surname and language diversity accounts for about 35% of the differentiation. Both Lasker and dialectometric distances identify very similar boundaries between Poitou, Centre, Bourgogne and Franche Comptée at the North, and Aquitaine, Limousin, Auvergne, Rhône-Alpes in the South. Average Fisher's alpha for France was 7877 the highest value observed for the European countries studied to date. The size of alpha in most French towns indicates considerable recent immigration.

  14. Nonlinear structural analysis using integrated force method

    Indian Academy of Sciences (India)

    Force method in the pre-computer era was the popular analysis tool for civil, mechanical and aerospace engineering structures. This popularity can be attributed to its ability to determine accurate estimates of forces in the structure. During the formulative period of structural analysis by matrix methods, earnest research was ...

  15. Temperature dependent structural evolution in liquid Ag50Ga50 alloy

    Science.gov (United States)

    Su, Y.; Wang, X. D.; Yu, Q.; Cao, Q. P.; Ruett, U.; Zhang, D. X.; Jiang, J. Z.

    2018-01-01

    The temperature dependence of atomic structural evolution in liquid Ag50Ga50 alloy has been studied using an in situ high energy x-ray diffraction (XRD) experiment combined with first-principles molecular dynamics (FPMD) simulations. The experimental data show a reversible structural crossover at the temperature of about 1050 K. Changes in both electrical resistivity and absolute thermoelectric power at about 1100 K strongly support the XRD results. Additionally, FPMD simulations reveal the abnormal temperature dependent behavior of partial coordination number and atomic diffusivity at about 1200 K, elucidating that the partition experimentally observed changes in structure and properties could be linked with the repartition between Ag and Ga atoms in the liquid at around 1050–1200 K. This finding will trigger more studies on the structural evolution of noble-polyvalent metals in particular and metallic liquids in general.

  16. Time-evolution operators for (coupled) time-dependent oscillators and Lie algebraic structure theory

    Science.gov (United States)

    Wolf, F.; Korsch, H. J.

    1988-03-01

    This paper deals with the application of Lie algebraic structure theory to time-dependent quantum systems making use of the Levi-Malcev decomposition of the Lie algebra generated by the Hamiltonian and the Wei-Norman representation of the time-evolution operator. In particular, (coupled) harmonic-oscillator systems are studied. Explicit formulas for expectation values and transition probabilities are derived.

  17. Structure evolution of .alpha.- and .beta.-polypropylenes upon UV irradiation: A multiscale comparison

    Czech Academy of Sciences Publication Activity Database

    Obadal, M.; Čermák, R.; Raab, Miroslav; Verney, V.; Commereuc, S.; Fraisse, F.

    2005-01-01

    Roč. 88, č. 3 (2005), s. 532-539 ISSN 0141-3910 R&D Projects: GA ČR(CZ) GA106/02/1249 Keywords : .beta.-polypropylene * photo-oxidation * structure evolution Subject RIV: JJ - Other Materials Impact factor: 1.749, year: 2005

  18. From fast to slow processes in the evolution of urban and regional settlement structures

    Directory of Open Access Journals (Sweden)

    Wolfgang Weidlich

    1999-01-01

    Full Text Available Complex systems consist of many intertwined organizational levels starting from micro-structures and ending with macrostructures. Their evolution takes place on different time scales: Micropatterns exhibit a fast dynamics whereas macropatterns develop slowly. Urban and regional science can make use of this fact by constructing a hierarchy of models on different spatio-temporal scales.

  19. Kinematic morphology of large-scale structure: evolution from potential to rotational flow

    International Nuclear Information System (INIS)

    Wang, Xin; Szalay, Alex; Aragón-Calvo, Miguel A.; Neyrinck, Mark C.; Eyink, Gregory L.

    2014-01-01

    As an alternative way to describe the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these invariants, defined as coefficients of the characteristic equation of the velocity gradient tensor, enable a complete classification of all possible flow patterns in the dark-matter comoving frame, including both potential and vortical flows. We show that this tool, first introduced in turbulence two decades ago, is very useful for understanding the evolution of the cosmic web structure, and in classifying its morphology. Before shell crossing, different categories of potential flow are highly associated with the cosmic web structure because of the coherent evolution of density and velocity. This correspondence is even preserved at some level when vorticity is generated after shell crossing. The evolution from the potential to vortical flow can be traced continuously by these invariants. With the help of this tool, we show that the vorticity is generated in a particular way that is highly correlated with the large-scale structure. This includes a distinct spatial distribution and different types of alignment between the cosmic web and vorticity direction for various vortical flows. Incorporating shell crossing into closed dynamical systems is highly non-trivial, but we propose a possible statistical explanation for some of the phenomena relating to the internal structure of the three-dimensional invariant space.

  20. Regge-like initial input and evolution of non-singlet structure ...

    Indian Academy of Sciences (India)

    The non-singlet structure functions, evolved in accordance with DGLAP evolution equations up to next-next-to-leading order are studied phenomenologically in comparison with the available experimental and parametrization results taken from NMC, CCFR, NuTeV, CORUS, CDHSW, NNPDF and MSTW Collaborations and ...

  1. Oxygen Evolution at Hematite Surfaces: The Impact of Structure and Oxygen Vacancies on Lowering the Overpotential

    NARCIS (Netherlands)

    Zhang, X.; Klaver, P.; van Santen, R.; van de Sanden, M. C. M.; Bieberle, A.

    2016-01-01

    Simulations of the oxygen evolution reaction (OER) are essential for understanding the limitations of water splitting. Most research has focused so far on the OER at flat metal oxide surfaces. The structure sensitivity of the OER has, however, recently been highlighted as a promising research

  2. Structural Evolution in Photoactive Yellow Protein Studied by Femtosecond Stimulated Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    Yoshizawa M.

    2013-03-01

    Full Text Available Ultrafast structural evolution in photoactive yellow protein (PYP is studied by femtosecond stimulated Raman spectroscopy. A comparison between wild-type PYP and E46Q mutant reveals that the hydrogen-bonding network surrounding the chromophore of PYP is immediately rearranged in the electronic excited state.

  3. Structure and Evolution of Mediterranean Forest Research: A Science Mapping Approach.

    Science.gov (United States)

    Nardi, Pierfrancesco; Di Matteo, Giovanni; Palahi, Marc; Scarascia Mugnozza, Giuseppe

    2016-01-01

    This study aims at conducting the first science mapping analysis of the Mediterranean forest research in order to elucidate its research structure and evolution. We applied a science mapping approach based on co-term and citation analyses to a set of scientific publications retrieved from the Elsevier's Scopus database over the period 1980-2014. The Scopus search retrieved 2,698 research papers and reviews published by 159 peer-reviewed journals. The total number of publications was around 1% (N = 17) during the period 1980-1989 and they reached 3% (N = 69) in the time slice 1990-1994. Since 1995, the number of publications increased exponentially, thus reaching 55% (N = 1,476) during the period 2010-2014. Within the thirty-four years considered, the retrieved publications were published by 88 countries. Among them, Spain was the most productive country, publishing 44% (N = 1,178) of total publications followed by Italy (18%, N = 482) and France (12%, N = 336). These countries also host the ten most productive scientific institutions in terms of number of publications in Mediterranean forest subjects. Forest Ecology and Management and Annals of Forest Science were the most active journals in publishing research in Mediterranean forest. During the period 1980-1994, the research topics were poorly characterized, but they become better defined during the time slice 1995-1999. Since 2000s, the clusters become well defined by research topics. Current status of Mediterranean forest research (20092014) was represented by four clusters, in which different research topics such as biodiversity and conservation, land-use and degradation, climate change effects on ecophysiological responses and soil were identified. Basic research in Mediterranean forest ecosystems is mainly conducted by ecophysiological research. Applied research was mainly represented by land-use and degradation, biodiversity and conservation and fire research topics. The citation analyses revealed highly

  4. Structure and Evolution of Mediterranean Forest Research: A Science Mapping Approach.

    Directory of Open Access Journals (Sweden)

    Pierfrancesco Nardi

    Full Text Available This study aims at conducting the first science mapping analysis of the Mediterranean forest research in order to elucidate its research structure and evolution. We applied a science mapping approach based on co-term and citation analyses to a set of scientific publications retrieved from the Elsevier's Scopus database over the period 1980-2014. The Scopus search retrieved 2,698 research papers and reviews published by 159 peer-reviewed journals. The total number of publications was around 1% (N = 17 during the period 1980-1989 and they reached 3% (N = 69 in the time slice 1990-1994. Since 1995, the number of publications increased exponentially, thus reaching 55% (N = 1,476 during the period 2010-2014. Within the thirty-four years considered, the retrieved publications were published by 88 countries. Among them, Spain was the most productive country, publishing 44% (N = 1,178 of total publications followed by Italy (18%, N = 482 and France (12%, N = 336. These countries also host the ten most productive scientific institutions in terms of number of publications in Mediterranean forest subjects. Forest Ecology and Management and Annals of Forest Science were the most active journals in publishing research in Mediterranean forest. During the period 1980-1994, the research topics were poorly characterized, but they become better defined during the time slice 1995-1999. Since 2000s, the clusters become well defined by research topics. Current status of Mediterranean forest research (20092014 was represented by four clusters, in which different research topics such as biodiversity and conservation, land-use and degradation, climate change effects on ecophysiological responses and soil were identified. Basic research in Mediterranean forest ecosystems is mainly conducted by ecophysiological research. Applied research was mainly represented by land-use and degradation, biodiversity and conservation and fire research topics. The citation analyses

  5. Gene structure and evolution of transthyretin in the order Chiroptera.

    Science.gov (United States)

    Khwanmunee, Jiraporn; Leelawatwattana, Ladda; Prapunpoj, Porntip

    2016-02-01

    Bats are mammals in the order Chiroptera. Although many extensive morphologic and molecular genetics analyses have been attempted, phylogenetic relationships of bats has not been completely resolved. The paraphyly of microbats is of particular controversy that needs to be confirmed. In this study, we attempted to use the nucleotide sequence of transthyretin (TTR) intron 1 to resolve the relationship among bats. To explore its utility, the complete sequences of TTR gene and intron 1 region of bats in Vespertilionidae: genus Eptesicus (Eptesicus fuscus) and genus Myotis (Myotis brandtii, Myotis davidii, and Myotis lucifugus), and Pteropodidae (Pteropus alecto and Pteropus vampyrus) were extracted from the retrieved sequences, whereas those of Rhinoluphus affinis and Scotophilus kuhlii were amplified and sequenced. The derived overall amino sequences of bat TTRs were found to be very similar to those in other eutherians but differed from those in other classes of vertebrates. However, missing of amino acids from N-terminal or C-terminal region was observed. The phylogenetic analysis of amino acid sequences suggested bat and other eutherian TTRs lineal descent from a single most recent common ancestor which differed from those of non-placental mammals and the other classes of vertebrates. The splicing of bat TTR precursor mRNAs was similar to those of other eutherian but different from those of marsupial, bird, reptile and amphibian. Based on TTR intron 1 sequence, the inferred evolutionary relationship within Chiroptera revealed more closely relatedness of R. affinis to megabats than to microbats. Accordingly, the paraphyly of microbats was suggested.

  6. Decision analysis for deteriorating structures

    International Nuclear Information System (INIS)

    Val, Dimitri V.; Stewart, Mark G.

    2005-01-01

    Measures that improve durability of a structure usually increase its initial cost. Thus, in order to make a decision about a cost-effective solution the life-cycle cost of a structure including cost of structural failure needs to be considered. Due to uncertainties associated with structural properties, loads and environmental conditions the cost of structural failure is a random variable. The paper derives probability distributions of the cost of failure of a single structure and a group of identical structures when single or multiple failures are possible during the service life of a structure. The probability distributions are based on cumulative probabilities of failure of a single structure over its service life. It is assumed that failures occur at discrete points in time, the cost of failure set at the time of decision making remains constant for a particular design solution and the discount rate is a deterministic parameter not changing with time. The probability distributions can be employed to evaluate the expected life-cycle cost or the expected utility, which is then used in decision making. An example, which considers the selection of durability specifications for a reinforced concrete structure built on the coast, illustrates the use of the derived probability distributions

  7. Friction-induced nano-structural evolution of graphene as a lubrication additive

    Science.gov (United States)

    Zhao, Jun; Mao, Junyuan; Li, Yingru; He, Yongyong; Luo, Jianbin

    2018-03-01

    Graphene has attracted enormous attention in the field of lubrication based on its excellent physical and chemical properties. Although many studies have obtained thermally or chemically- exfoliated graphene and investigated their wide and important application, few studies have reported their physical nano-structural evolution under friction. In this study, we investigated the lubrication properties of graphene additives with different layer numbers and interlayer spacing by exfoliating. The additives with a higher degrees of exfoliation changed to ordering under friction, and had better lubrication properties, while that with a lower degrees exhibited obvious structural defects and high friction. Therefore, the original degrees of exfoliation plays a key role in the structural evolution of graphene and superior lubrication can be achieved through the physical nano-structure changing to ordering, even graphitization. Furthermore, the ordered tribofilm on the frictional interfaces was parallel to the sliding direction, meaning the highly exfoliated graphene indeed reaching slippage between its layers, which wasn't experimentally discovered in previous studies. This work provides a new understanding of the relationship between friction-induced nano-structural evolution and lubrication properties of graphene as a lubrication additive, and has great potential for the structural design of graphene as a lubrication additive.

  8. A Bayesian Network Based Adaptability Design of Product Structures for Function Evolution

    Directory of Open Access Journals (Sweden)

    Shaobo Li

    2018-03-01

    Full Text Available Structure adaptability design is critical for function evolution in product families, in which many structural and functional design factors are intertwined together with manufacturing cost, customer satisfaction, and final market sales. How to achieve a delicate balance among all of these factors to maximize the market performance of the product is too complicated to address based on traditional domain experts’ knowledge or some ad hoc heuristics. Here, we propose a quantitative product evolution design model that is based on Bayesian networks to model the dynamic relationship between customer needs and product structure design. In our model, all of the structural or functional features along with customer satisfaction, manufacturing cost, sale price, market sales, and indirect factors are modeled as random variables denoted as nodes in the Bayesian networks. The structure of the Bayesian model is then determined based on the historical data, which captures the dynamic sophisticated relationship of customer demands of a product, structural design, and market performance. Application of our approach to an electric toothbrush product family evolution design problem shows that our model allows for designers to interrogate with the model and obtain theoretical and decision support for dynamic product feature design process.

  9. Evolution of the Exon-Intron Structure in Ciliate Genomes.

    Directory of Open Access Journals (Sweden)

    Vladyslav S Bondarenko

    Full Text Available A typical eukaryotic gene is comprised of alternating stretches of regions, exons and introns, retained in and spliced out a mature mRNA, respectively. Although the length of introns may vary substantially among organisms, a large fraction of genes contains short introns in many species. Notably, some Ciliates (Paramecium and Nyctotherus possess only ultra-short introns, around 25 bp long. In Paramecium, ultra-short introns with length divisible by three (3n are under strong evolutionary pressure and have a high frequency of in-frame stop codons, which, in the case of intron retention, cause premature termination of mRNA translation and consequent degradation of the mis-spliced mRNA by the nonsense-mediated decay mechanism. Here, we analyzed introns in five genera of Ciliates, Paramecium, Tetrahymena, Ichthyophthirius, Oxytricha, and Stylonychia. Introns can be classified into two length classes in Tetrahymena and Ichthyophthirius (with means 48 bp, 69 bp, and 55 bp, 64 bp, respectively, but, surprisingly, comprise three distinct length classes in Oxytricha and Stylonychia (with means 33-35 bp, 47-51 bp, and 78-80 bp. In most ranges of the intron lengths, 3n introns are underrepresented and have a high frequency of in-frame stop codons in all studied species. Introns of Paramecium, Tetrahymena, and Ichthyophthirius are preferentially located at the 5' and 3' ends of genes, whereas introns of Oxytricha and Stylonychia are strongly skewed towards the 5' end. Analysis of evolutionary conservation shows that, in each studied genome, a significant fraction of intron positions is conserved between the orthologs, but intron lengths are not correlated between the species. In summary, our study provides a detailed characterization of introns in several genera of Ciliates and highlights some of their distinctive properties, which, together, indicate that splicing spellchecking is a universal and evolutionarily conserved process in the biogenesis of short

  10. High Resolution Structure of Deinococcus Bacteriophytochrome Yields New Insights into Phytochrome Architecture and Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Jeremiah R.; Zhang, Junrui; Brunzelle, Joseph S.; Vierstra, Richard D.; Forest, Katrina T. (NWU); (UW)

    2010-03-08

    Phytochromes are red/far red light photochromic photoreceptors that direct many photosensory behaviors in the bacterial, fungal, and plant kingdoms. They consist of an N-terminal domain that covalently binds a bilin chromophore and a C-terminal region that transmits the light signal, often through a histidine kinase relay. Using x-ray crystallography, we recently solved the first three-dimensional structure of a phytochrome, using the chromophore-binding domain of Deinococcus radiodurans bacterial phytochrome assembled with its chromophore, biliverdin IX{alpha}. Now, by engineering the crystallization interface, we have achieved a significantly higher resolution model. This 1.45 {angstrom} resolution structure helps identify an extensive buried surface between crystal symmetry mates that may promote dimerization in vivo. It also reveals that upon ligation of the C3{sup 2} carbon of biliverdin to Cys{sup 24}, the chromophore A-ring assumes a chiral center at C2, thus becoming 2(R),3(E)-phytochromobilin, a chemistry more similar to that proposed for the attached chromophores of cyanobacterial and plant phytochromes than previously appreciated. The evolution of bacterial phytochromes to those found in cyanobacteria and higher plants must have involved greater fitness using more reduced bilins, such as phycocyanobilin, combined with a switch of the attachment site from a cysteine near the N terminus to one conserved within the cGMP phosphodiesterase/adenyl cyclase/FhlA domain. From analysis of site-directed mutants in the D. radiodurans phytochrome, we show that this bilin preference was partially driven by the change in binding site, which ultimately may have helped photosynthetic organisms optimize shade detection. Collectively, these three-dimensional structural results better clarify bilin/protein interactions and help explain how higher plant phytochromes evolved from prokaryotic progenitors.

  11. Structure, expression differentiation and evolution of duplicated fiber developmental genes in Gossypium barbadense and G. hirsutum.

    Science.gov (United States)

    Zhu, Huayu; Han, Xiaoyong; Lv, Junhong; Zhao, Liang; Xu, Xiaoyang; Zhang, Tianzhen; Guo, Wangzhen

    2011-02-25

    Both Gossypium hirsutum and G. barbadense probably originated from a common ancestor, but they have very different agronomic and fiber quality characters. Here we selected 17 fiber development-related genes to study their structures, tree topologies, chromosomal location and expression patterns to better understand the interspecific divergence of fiber development genes in the two cultivated tetraploid species. The sequence and structure of 70.59% genes were conserved with the same exon length and numbers in different species, while 29.41% genes showed diversity. There were 15 genes showing independent evolution between the A- and D-subgenomes after polyploid formation, while two evolved via different degrees of colonization. Chromosomal location showed that 22 duplicate genes were located in which at least one fiber quality QTL was detected. The molecular evolutionary rates suggested that the D-subgenome of the allotetraploid underwent rapid evolutionary differentiation, and selection had acted at the tetraploid level. Expression profiles at fiber initiation and early elongation showed that the transcripts levels of most genes were higher in Hai7124 than in TM-1. During the primary-secondary transition period, expression of most genes peaked earlier in TM-1 than in Hai7124. Homeolog expression profile showed that A-subgenome, or the combination of A- and D-subgenomes, played critical roles in fiber quality divergence of G. hirsutum and G. barbadense. However, the expression of D-subgenome alone also played an important role. Integrating analysis of the structure and expression to fiber development genes, suggests selective breeding for certain desirable fiber qualities played an important role in divergence of G. hirsutum and G. barbadense.

  12. Development of a Prognostic Marker for Lung Cancer Using Analysis of Tumor Evolution

    Science.gov (United States)

    2017-08-01

    AWARD NUMBER: W81XWH-15-1-0243 TITLE: Development of a Prognostic Marker for Lung Cancer Using Analysis of Tumor Evolution PRINCIPAL...SUBTITLE 5a. CONTRACT NUMBER Development of a Prognostic Marker for Lung Cancer Using Analysis of Tumor Evolution 5b. GRANT NUMBER 5c. PROGRAM...derive a prognostic classifier. 15. SUBJECT TERMS NSCLC; tumor evolution ; whole exome sequencing 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  13. PLASTIC ANALYSIS OF STEEL FRAME STRUCTURE

    Directory of Open Access Journals (Sweden)

    M. Rogac

    2013-05-01

    Full Text Available This paper presents the plastic analysis of steel frame structure loaded by gravity loads. By applying the cinematic theorem of ultimate analysis, the ultimate load for the case of elastic - ideally plastic material is calculated. The identical structure was treated in the computer program SAP2000 where the zone of material reinforcement in the plastic area was covered. Keywords: Steel frame structure, plastic analysis, ultimate gravity load, material reinforcement.

  14. Structure and evolution of irradiated accretion disks. I - Static thermal equilibrium structure. II - Dynamical evolution of a thermally unstable torus

    Science.gov (United States)

    Tuchman, Y.; Mineshige, S.; Wheeler, J. C.

    1990-01-01

    The thermal equilibrum structure and dynamical behavior of externally irradiated accretion disks are investigated. For radiative disks only the surface layer is heated, while for convective disks the heat penetrates deeply into the disk. For sufficiently strong radiation and given irradiation flux F(irr), the disk is completely stabilized against thermal instabilities of the sort invoked to explain dwarf novae. For moderately strong irradiation there is still an unstable branch in the thermal equilibrium curve. In typical soft X-ray transients, the disk is unstable against the dwarf-nova type instability. Fixed F(irr) on accretion disk annuli reduces the amplitude and the quiescent times and increases the outburst duration of the resultant light curves. Varying F(irr) in proportion to the mass accretion rate at the disks's inner edge results in light curves with a plateau in the decay from outbursts. In the case when irradiation is suddenly switched on, a temperature inversion results which leads to the formation of an accretion corona.

  15. Robustness Analysis of Kinetic Structures

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

    2009-01-01

    Kinetic structures in architecture follows a new trend which is emerging in responsive architecture coined by Nicholas Negroponte when he proposed that architecture may benefit from the integration of computing power into built spaces and structures, and that better performing, more rational...

  16. Structural setting and evolution of the Mensa and Thunder Horse intraslope basins, northern deep-water Gulf of Mexico: A case study

    NARCIS (Netherlands)

    Weimer, P.; Bouroullec, R.; Berg, A.A. van den; Lapinski, T.G.; Roesink, J.G.; Adson, J.

    2017-01-01

    The Mensa and Thunder Horse intraslope minibasins in southcentralMississippi Canyon, northern deep-water Gulf ofMexico, had a linked structural evolution from the Early Cretaceous through the late Miocene. Analysis of the two minibasins illustrates the complexities of deep-water sedimentation and

  17. Edge-exposed MoS2 nano-assembled structures as efficient electrocatalysts for hydrogen evolution reaction.

    Science.gov (United States)

    Chung, Dong Young; Park, Seung-Keun; Chung, Young-Hoon; Yu, Seung-Ho; Lim, Dong-Hee; Jung, Namgee; Ham, Hyung Chul; Park, Hee-Young; Piao, Yuanzhe; Yoo, Sung Jong; Sung, Yung-Eun

    2014-02-21

    Edge-exposed MoS2 nano-assembled structures are designed for high hydrogen evolution reaction activity and long term stability. The number of sulfur edge sites of nano-assembled spheres and sheets is confirmed by Raman spectroscopy and EXAFS analysis. By controlling the MoS2 morphology with the formation of nano-assembled spheres with the assembly of small-size fragments of MoS2, the resulting assembled spheres have high electrocatalytic HER activity and high thermodynamic stability.

  18. Chemical structure influence on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux

    Science.gov (United States)

    Padgett, Mark C.; Tick, Geoffrey R.; Carroll, Kenneth C.; Burke, William R.

    2017-03-01

    The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions > 0.05 to nonideality as mole fractions decreased. In particular, the TCE generally exhibited more ideal dissolution behavior except at lower mole fractions, and may indicate greater structural/polarity similarity between the two compounds. Raoult's Law and UNIFAC generally under-predicted the batch experiment results for TOL:HEXDEC mixtures especially for mole fractions ≤ 0.05. The dissolution rate coefficients were similar for both TOL and TCE over all mole fractions tested. Mass flux reduction (MFR) analysis showed that more efficient removal behavior occurred for TOL and TCE with larger mole fractions compared to the lower initial mole fraction mixtures (i.e. < 0.2). However, compared to TOL, TCE generally exhibited more efficient removal behavior over all mole fractions tested and may have been the result of structural and molecular property differences between the compounds. Activity coefficient variability as a function of mole fraction was quantified through regression analysis and incorporated into dissolution modeling analyses for the dynamic flushing experiments. TOL elution concentrations were modeled (predicted) reasonable well using ideal and equilibrium assumptions, but the TCE elution concentrations could not be predicted using the ideal model. Rather, the dissolution modeling demonstrated that TCE elution was better described by the nonideal model whereby NAPL-phase activity coefficient varied as a function of COC mole

  19. The IQD gene family in soybean: structure, phylogeny, evolution and expression.

    Directory of Open Access Journals (Sweden)

    Lin Feng

    Full Text Available Members of the plant-specific IQ67-domain (IQD protein family are involved in plant development and the basal defense response. Although systematic characterization of this family has been carried out in Arabidopsis, tomato (Solanum lycopersicum, Brachypodium distachyon and rice (Oryza sativa, systematic analysis and expression profiling of this gene family in soybean (Glycine max have not previously been reported. In this study, we identified and structurally characterized IQD genes in the soybean genome. A complete set of 67 soybean IQD genes (GmIQD1-67 was identified using Blast search tools, and the genes were clustered into four subfamilies (IQD I-IV based on phylogeny. These soybean IQD genes are distributed unevenly across all 20 chromosomes, with 30 segmental duplication events, suggesting that segmental duplication has played a major role in the expansion of the soybean IQD gene family. Analysis of the Ka/Ks ratios showed that the duplicated genes of the GmIQD family primarily underwent purifying selection. Microsynteny was detected in most pairs: genes in clade 1-3 might be present in genome regions that were inverted, expanded or contracted after the divergence; most gene pairs in clade 4 showed high conservation with little rearrangement among these gene-residing regions. Of the soybean IQD genes examined, six were most highly expressed in young leaves, six in flowers, one in roots and two in nodules. Our qRT-PCR analysis of 24 soybean IQD III genes confirmed that these genes are regulated by MeJA stress. Our findings present a comprehensive overview of the soybean IQD gene family and provide insights into the evolution of this family. In addition, this work lays a solid foundation for further experiments aimed at determining the biological functions of soybean IQD genes in growth and development.

  20. Direct visualization of pH-dependent evolution of structure and dynamics in microgel suspensions

    International Nuclear Information System (INIS)

    Muluneh, M; Sprakel, J; Weitz, D A; Wyss, H M; Mattsson, J

    2011-01-01

    We use 3D confocal microscopy combined with image analysis and particle tracking techniques to study the structure and dynamics of aqueous suspensions of fluorescently labelled p(NIPAm-co-AAc) microgel particles. By adjusting the pH we can tune the interactions between the microgel particles from purely repulsive near neutral pH, to weakly attractive at low pH. This change in the interaction potential has a pronounced effect on the manner in which the suspensions solidify. We directly follow the evolution of the system after a quench from the liquid state to obtain detailed information on the route to kinetic arrest. At low pH and low concentration, dynamic arrest results mainly from crystallization driven by the attraction between particles; crystal nucleation occurs homogeneously throughout the sample and does not appear to be localized to geometric boundaries. Moreover, the growth of crystals is characterized by nucleation-limited kinetics where a rapid growth of crystal domains takes place after a long concentration-dependent lag time. At low pH and high concentration, relaxation of the suspension is constrained and it evolves only slightly, resulting in a disordered solid. At neutral pH, the dynamics are a function of the particle number concentration only; a high concentration leads to the formation of a disordered soft glassy solid. (paper)

  1. Clustering in community structure across replicate ecosystems following a long-term bacterial evolution experiment.

    Science.gov (United States)

    Celiker, Hasan; Gore, Jeff

    2014-08-08

    Experiments to date probing adaptive evolution have predominantly focused on studying a single species or a pair of species in isolation. In nature, on the other hand, species evolve within complex communities, interacting and competing with many other species. It is unclear how reproducible or predictable adaptive evolution is within the context of a multispecies ecosystem. To explore this problem, we let 96 replicates of a multispecies laboratory bacterial ecosystem evolve in parallel for hundreds of generations. Here we find that relative abundances of individual species vary greatly across the evolved ecosystems and that the final profile of species frequencies within replicates clusters into several distinct types, as opposed to being randomly dispersed across the frequency space or converging fully. Our results suggest that community structure evolution has a tendency to follow one of only a few distinct paths.

  2. A computational model for domain structure evolution of nematic liquid crystal elastomers

    Science.gov (United States)

    Wang, Hongbo; Oates, William S.

    2009-03-01

    Liquid crystal elastomers combine both liquid crystals and polymers, which gives rise to many fascinating properties, such as unparalleled elastic anisotropy, photo-mechanics and flexoelectric behavior. The potential applications for these materials widely range from wings for micro-air vehicles to reversible adhesion skins for mobile climbing robots. However, significant challenges remain to understand the rich range of microstructure evolution exibited by these materials. This paper presents a model for domain structure evolution within the Ginzburg-Landau framework. The free energy consists of two parts: the distortion energy introduced by Ericksen [1] and a Landau energy. The finite element method has been implemented to solve the governing equations developed. Numerical examples are given to demonstrate the microstructure evolution.

  3. Understanding the process of social network evolution: Online-offline integrated analysis of social tie formation.

    Science.gov (United States)

    Kwak, Doyeon; Kim, Wonjoon

    2017-01-01

    It is important to consider the interweaving nature of online and offline social networks when we examine social network evolution. However, it is difficult to find any research that examines the process of social tie formation from an integrated perspective. In our study, we quantitatively measure offline interactions and examine the corresponding evolution of online social network in order to understand the significance of interrelationship between online and offline social factors in generating social ties. We analyze the radio signal strength indicator sensor data from a series of social events to understand offline interactions among the participants and measure the structural attributes of their existing online Facebook social networks. By monitoring the changes in their online social networks before and after offline interactions in a series of social events, we verify that the ability to develop an offline interaction into an online friendship is tied to the number of social connections that participants previously had, while the presence of shared mutual friends between a pair of participants disrupts potential new connections within the pre-designed offline social events. Thus, while our integrative approach enables us to confirm the theory of preferential attachment in the process of network formation, the common neighbor theory is not supported. Our dual-dimensional network analysis allows us to observe the actual process of social network evolution rather than to make predictions based on the assumption of self-organizing networks.

  4. COMPARATIVE ANALYSIS OF STEEL AND ALUMINUM STRUCTURES

    Directory of Open Access Journals (Sweden)

    Josip Peko

    2016-12-01

    Full Text Available This study examined steel and aluminum variants of modern exhibition structures in which the main design requirements include low weight (increased span/depth ratio, transportation, and construction and durability (resistance to corrosion. This included a design situation in which the structural application of aluminum alloys provided an extremely convenient and practical solution. Viability of an aluminum structure depends on several factors and requires a detailed analysis. The overall conclusion of the study indicated that aluminum can be used as a structural material and as a viable alternative to steel for Croatian snow and wind load values and evidently in cases in which positive properties of aluminum are required for structural design. Furthermore, a structural fire analysis was conducted for an aluminum variant structure by using a zone model for realistic fire analysis. The results suggested that passive fire protection for the main structural members was not required in the event of areal fire with duration of 60 min.

  5. NASA Structural Analysis System (NASTRAN)

    Science.gov (United States)

    Purves, L.

    1991-01-01

    Program aids in structural design of wide range of objects, from high-impact printer parts to turbine engine blades, and fully validated. Since source code included, NASTRAN modified or enhanced for new applications.

  6. Evolution of granule structure and drug content during fluidized bed granulation by X-ray microtomography and confocal Raman spectroscopy.

    Science.gov (United States)

    Poutiainen, Sami; Pajander, Jari; Savolainen, Armi; Ketolainen, Jarkko; Järvinen, Kristiina

    2011-12-01

    The distribution of the drug in the granular end product is a critical quality attribute in fluidized bed spray granulation of pharmaceuticals. The evolution of drug content inhomogeneity in a case study was examined as a function of granulation time. Intragranular structure was also investigated using confocal Raman spectroscopy and computerized X-ray microtomography. A principal component analysis was conducted on the results to investigate granule structure-drug content relationships. Inhomogeneity increased at the beginning of the process but later it was found to decrease. Changes in the homogeneity were accompanied by significant changes in the intragranular structure. It was concluded that segregation of the primary components explained the observed inhomogeneity at low saturation levels when the granules grow by layering, but at elevated moisture levels, granule growth is mediated by the coalescence of agglomerates, which promotes homogeneous distribution of the drug particles. Copyright © 2011 Wiley-Liss, Inc.

  7. Mathematical and computational analyses of cracking formation fracture morphology and its evolution in engineering materials and structures

    CERN Document Server

    Sumi, Yoichi

    2014-01-01

    This book is about the pattern formation and the evolution of crack propagation in engineering materials and structures, bridging mathematical analyses of cracks based on singular integral equations, to computational simulation of engineering design. The first two parts of this book focus on elasticity and fracture and provide the basis for discussions on fracture morphology and its numerical simulation, which may lead to a simulation-based fracture control in engineering structures. Several design concepts are discussed for the prevention of fatigue and fracture in engineering structures, including safe-life design, fail-safe design, damage tolerant design. After starting with basic elasticity and fracture theories in parts one and two, this book focuses on the fracture morphology that develops due to the propagation of brittle cracks or fatigue cracks.   In part three, the mathematical analysis of a curved crack is precisely described, based on the perturbation method. The stability theory of interactive ...

  8. COMPARATIVE ANALYSIS OF THE RECENT EVOLUTIONS OF ROMANIAN AND EUROPEAN UNION'S COMPETITIVENESS

    Directory of Open Access Journals (Sweden)

    Felea Adrian Ioan

    2011-07-01

    Full Text Available The main subject of this paper refers to an analysis of the recent trends and evolution of Romanian competitiveness compared to the European Union competitiveness and it is structured in four main parts. The first section of the paper regards an introduction of the competitiveness evolution process, recalling the three actual evaluation models of the competitiveness level. In the second part of the paper there can be found the competitiveness indexes practiced and published by the World Economic Forum, indicators that are structured on three main levels as following: the Global Competitiveness Index and its aggregate indicators that are developed on three categories of factors that are essential for the competitiveness process (Basic requirements, Efficienty Enhancers, Innovation and sophistication factors and the indexes associated to the twelve pillars of competitiveness: Institutions, Infrastructure, Macroeconomic stability, Health and primary education, Higer education and training, Goods market efficiency, Labor market efficiency, Financial market sophistication Technological readiness, Market size, Business sophistication, Innovation. Based on the values obtained after consulting the World Economic Forum Reports and regarding the competitiveness from a global perspective, the third part of the paper presents a comparative analyisis of the evolution of the Romanian competitiveness process and the one of the EU25. In the last part of the paper there can be found the conclusions of this analysis, with respect to the values found This paper is part of the doctoral thesis entitled "Increased Competitiveness in the Romanian economy, in the context of Sustainable Development, coordinated by Professor Michael Berinde University of Oradea, Faculty of Economics. Doctoral research is supported by Human Resources Development Operational Programme 2007-2013, Contract POSDRU/CPP107/DMI1.5/S/80272 , "Doctoral programs to train researchers performing

  9. Autodesk robot structural analysis professional 2016 essentials

    CERN Document Server

    Marsh, Ken

    2016-01-01

    Autodesk Robot Structural Analysis Professional 2016 - Essentials is an excellent introduction to the essential features, functions, and workflows of Autodesk Robot Structural Analysis Professional. Master the tools you will need to make Robot work for you: Go from zero to proficiency with this thorough and detailed introduction to the essential concepts and workflows of Robot Structural Analysis Professional 2016. - Demystify the interface - Manipulate and manage Robot tables like a pro - Learn how to use Robot's modeling tools - Master loading techniques - Harness Robot automated load combinations - Decipher simplified seismic loading - Discover workflows for steel and concrete design - Gain insights to help troubleshoot issues Guided exercises are provided to help cement fundamental concepts in Robot Structural Analysis and drive home key functions. Get up to speed quickly with this essential text and add Robot Structural Analysis Professional 2016 to your analysis and design toolbox. New in 2016: AWC-NDS ...

  10. Autodesk Robot Structural Analysis Professional 2016 essentials

    CERN Document Server

    Marsh, Ken

    2016-01-01

    Autodesk Robot Structural Analysis Professional 2016 - Essentials is an excellent introduction to the essential features, functions, and workflows of Autodesk Robot Structural Analysis Professional. Master the tools you will need to make Robot work for you: Go from zero to proficiency with this thorough and detailed introduction to the essential concepts and workflows of Robot Structural Analysis Professional 2016. - Demystify the interface - Manipulate and manage Robot tables like a pro - Learn how to use Robot's modeling tools - Master loading techniques - Harness Robot automated load combinations - Decipher simplified seismic loading - Discover workflows for steel and concrete design - Gain insights to help troubleshoot issues Guided exercises are provided to help cement fundamental concepts in Robot Structural Analysis and drive home key functions. Get up to speed quickly with this essential text and add Robot Structural Analysis Professional 2016 to your analysis and design toolbox. New in 2016: AWC-NDS ...

  11. An x-space analysis of evolution equations: Soffer's inequality and the non-forward evolution

    International Nuclear Information System (INIS)

    Cafarella, Alessandro; Coriano, Claudio; Guzzi, Marco

    2003-01-01

    We analyze the use of algorithms based in x-space for the solution of renormalization group equations of DGLAP-type and test their consistency by studying bounds among partons distributions - in our specific case Soffer's inequality and the perturbative behaviour of the nucleon tensor charge - to next-to-leading order in QCD. A discussion of the perturbative resummation implicit in these expansions using Mellin moments is included. We also comment on the (kinetic) proof of positivity of the evolution of h1, using a kinetic analogy and illustrate the extension of the algorithm to the evolution of generalized parton distributions. We prove positivity of the non-forward evolution in a special case and illustrate a Fokker-Planck approximation to it. (author)

  12. Automated analysis and design of complex structures

    International Nuclear Information System (INIS)

    Wilson, E.L.

    1977-01-01

    The present application of optimum design appears to be restricted to components of the structure rather than to the total structural system. Since design normally involved many analysis of the system any improvement in the efficiency of the basic methods of analysis will allow more complicated systems to be designed by optimum methods. The evaluation of the risk and reliability of a structural system can be extremely important. Reliability studies have been made of many non-structural systems for which the individual components have been extensively tested and the service environment is known. For such systems the reliability studies are valid. For most structural systems, however, the properties of the components can only be estimated and statistical data associated with the potential loads is often minimum. Also, a potentially critical loading condition may be completely neglected in the study. For these reasons and the previous problems associated with the reliability of both linear and nonlinear analysis computer programs it appears to be premature to place a significant value on such studies for complex structures. With these comments as background the purpose of this paper is to discuss the following: the relationship of analysis to design; new methods of analysis; new of improved finite elements; effect of minicomputer on structural analysis methods; the use of system of microprocessors for nonlinear structural analysis; the role of interacting graphics systems in future analysis and design. This discussion will focus on the impact of new, inexpensive computer hardware on design and analysis methods

  13. A Critical Analysis of Chromotherapy and Its Scientific Evolution

    Directory of Open Access Journals (Sweden)

    Samina T. Yousuf Azeemi

    2005-01-01

    Full Text Available Chromotherapy is a method of treatment that uses the visible spectrum (colors of electromagnetic radiation to cure diseases. It is a centuries-old concept used successfully over the years to cure various diseases. We have undertaken a critical analysis of chromotherapy and documented its scientific evolution to date. A few researchers have tried to discover the underlying scientific principles, but without quantitative study. Sufficient published material can be found about the subject that provides a complete system of treatment focused on the treatment methodologies and healing characteristics of colors. A number of studies have elaborated the relationship between the human body and colors. We also show the possibility of carrying out diverse research into chromotherapy that is pertinent to deciphering the quantum mechanical dipole moment of water molecules. The quantum mechanical dipole moment as a result of the absorption of different colors, we conjecture, produces charge quantization phenomena. This review illustrates that the development of science in the field of electromagnetic radiation/energy can be very helpful in discovering new dimensions of this old theory.

  14. A critical analysis of chromotherapy and its scientific evolution.

    Science.gov (United States)

    Azeemi, Samina T Yousuf; Raza, S Mohsin

    2005-12-01

    Chromotherapy is a method of treatment that uses the visible spectrum (colors) of electromagnetic radiation to cure diseases. It is a centuries-old concept used successfully over the years to cure various diseases. We have undertaken a critical analysis of chromotherapy and documented its scientific evolution to date. A few researchers have tried to discover the underlying scientific principles, but without quantitative study. Sufficient published material can be found about the subject that provides a complete system of treatment focused on the treatment methodologies and healing characteristics of colors. A number of studies have elaborated the relationship between the human body and colors. We also show the possibility of carrying out diverse research into chromotherapy that is pertinent to deciphering the quantum mechanical dipole moment of water molecules. The quantum mechanical dipole moment as a result of the absorption of different colors, we conjecture, produces charge quantization phenomena. This review illustrates that the development of science in the field of electromagnetic radiation/energy can be very helpful in discovering new dimensions of this old theory.

  15. Genome-Wide Analysis of Human Metapneumovirus Evolution.

    Directory of Open Access Journals (Sweden)

    Jin Il Kim

    Full Text Available Human metapneumovirus (HMPV has been described as an important etiologic agent of upper and lower respiratory tract infections, especially in young children and the elderly. Most of school-aged children might be introduced to HMPVs, and exacerbation with other viral or bacterial super-infection is common. However, our understanding of the molecular evolution of HMPVs remains limited. To address the comprehensive evolutionary dynamics of HMPVs, we report a genome-wide analysis of the eight genes (N, P, M, F, M2, SH, G, and L using 103 complete genome sequences. Phylogenetic reconstruction revealed that the eight genes from one HMPV strain grouped into the same genetic group among the five distinct lineages (A1, A2a, A2b, B1, and B2. A few exceptions of phylogenetic incongruence might suggest past recombination events, and we detected possible recombination breakpoints in the F, SH, and G coding regions. The five genetic lineages of HMPVs shared quite remote common ancestors ranging more than 220 to 470 years of age with the most recent origins for the A2b sublineage. Purifying selection was common, but most protein genes except the F and M2-2 coding regions also appeared to experience episodic diversifying selection. Taken together, these suggest that the five lineages of HMPVs maintain their individual evolutionary dynamics and that recombination and selection forces might work on shaping the genetic diversity of HMPVs.

  16. Cultural Transmission and Evolution of Melodic Structures in Multi-generational Signaling Games.

    Science.gov (United States)

    Lumaca, Massimo; Baggio, Giosuè

    2017-01-01

    It has been proposed that languages evolve by adapting to the perceptual and cognitive constraints of the human brain, developing, in the course of cultural transmission, structural regularities that maximize or optimize learnability and ease of processing. To what extent would perceptual and cognitive constraints similarly affect the evolution of musical systems? We conducted an experiment on the cultural evolution of artificial melodic systems, using multi-generational signaling games as a laboratory model of cultural transmission. Signaling systems, using five-tone sequences as signals, and basic and compound emotions as meanings, were transmitted from senders to receivers along diffusion chains in which the receiver in each game became the sender in the next game. During transmission, structural regularities accumulated in the signaling systems, following principles of proximity, symmetry, and good continuation. Although the compositionality of signaling systems did not increase significantly across generations, we did observe a significant increase in similarity among signals from the same set. We suggest that our experiment tapped into the cognitive and perceptual constraints operative in the cultural evolution of musical systems, which may differ from the mechanisms at play in language evolution and change.

  17. A Synthesis of Paleo-Present Stress and Structural Evolution in the Western Anadarko Basin

    Science.gov (United States)

    Gragg, E.; van Wijk, J.

    2017-12-01

    This research uses a compilation of geological and geophysical data from literature and public databases paired with new seismic, petrophysical and core analyses to deduce the stress and structural histories of the western Anadarko Basin from 1.3 Ga to present day. Paleo-stress fields are vital to understand fold-faulting styles, fracture networks, and the evolution of stratigraphic mechanics through time. These are features that can drastically influence paleo-present fluid migration and accumulations in the subsurface. This work is conducted in an effort to characterize risks to commercial-scale geologic carbon storage via CO2 Enhanced Oil Recovery. We conducted palinspastic restorations on a field-scale fault system using a 3D seismic survey, and also used a fault database produced by the Oklahoma Geological Survey in the analysis. Preliminary results indicate that stress field reorganization occurred multiple times, and is related to a variety of orogenic and epeirogenic events. Sparse age data allow us to constrain at least four of these stress field phases: 1) Mid-Proterozoic crustal grain development; 2) Cambrian Southern Oklahoma Aulacogen; 3) Late Mississippian orogeny, and Pennsylvanian epeirogeny; and 4) Cenozoic Laramide convergence. Stress states influence faulting style and fracture development that can impact CO2 storage and production performance. Future work will explore anthropogenic effects of prior and future production on the stress states and structures at the field scale via the construction of a 3D mechanical earth model coupled to flow simulators. Funding for this project is provided by the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) through the Southwest Partnership on Carbon Sequestration (SWP) under Award No. DE-FC26-05NT42591.

  18. A phylogenetic analysis of normal modes evolution in enzymes and its relationship to enzyme function.

    Science.gov (United States)

    Lai, Jason; Jin, Jing; Kubelka, Jan; Liberles, David A

    2012-09-21

    Since the dynamic nature of protein structures is essential for enzymatic function, it is expected that functional evolution can be inferred from the changes in protein dynamics. However, dynamics can also diverge neutrally with sequence substitution between enzymes without changes of function. In this study, a phylogenetic approach is implemented to explore the relationship between enzyme dynamics and function through evolutionary history. Protein dynamics are described by normal mode analysis based on a simplified harmonic potential force field applied to the reduced C(α) representation of the protein structure while enzymatic function is described by Enzyme Commission numbers. Similarity of the binding pocket dynamics at each branch of the protein family's phylogeny was analyzed in two ways: (1) explicitly by quantifying the normal mode overlap calculated for the reconstructed ancestral proteins at each end and (2) implicitly using a diffusion model to obtain the reconstructed lineage-specific changes in the normal modes. Both explicit and implicit ancestral reconstruction identified generally faster rates of change in dynamics compared with the expected change from neutral evolution at the branches of potential functional divergences for the α-amylase, D-isomer-specific 2-hydroxyacid dehydrogenase, and copper-containing amine oxidase protein families. Normal mode analysis added additional information over just comparing the RMSD of static structures. However, the branch-specific changes were not statistically significant compared to background function-independent neutral rates of change of dynamic properties and blind application of the analysis would not enable prediction of changes in enzyme specificity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Analysis and design of SSC underground structures

    International Nuclear Information System (INIS)

    Clark, G.T.

    1993-01-01

    This paper describes the analysis and design of underground structures for the Superconducting Super Collider (SSC) Project. A brief overview of the SSC Project and the types of underground structures are presented. Engineering properties and non-linear behavior of the geologic materials are reviewed. The three-dimensional sequential finite element rock-structure interaction analysis techniques developed by the author are presented and discussed. Several examples of how the method works, specific advantages, and constraints are presented. Finally, the structural designs that resulted from the sequential interaction analysis are presented

  20. FINITE ELEMENT ANALYSIS OF STRUCTURES

    Directory of Open Access Journals (Sweden)

    PECINGINA OLIMPIA-MIOARA

    2015-05-01

    Full Text Available The application of finite element method is analytical when solutions can not be applied for deeper study analyzes static, dynamic or other types of requirements in different points of the structures .In practice it is necessary to know the behavior of the structure or certain parts components of the machine under the influence of certain factors static and dynamic . The application of finite element in the optimization of components leads to economic growth , to increase reliability and durability organs studied, thus the machine itself.

  1. Comparable contributions of structural-functional constraints and expression level to the rate of protein sequence evolution

    Directory of Open Access Journals (Sweden)

    Koonin Eugene V

    2008-10-01

    Full Text Available Abstract Background Proteins show a broad range of evolutionary rates. Understanding the factors that are responsible for the characteristic rate of evolution of a given protein arguably is one of the major goals of evolutionary biology. A long-standing general assumption used to be that the evolution rate is, primarily, determined by the specific functional constraints that affect the given protein. These constrains were traditionally thought to depend both on the specific features of the protein's structure and its biological role. The advent of systems biology brought about new types of data, such as expression level and protein-protein interactions, and unexpectedly, a variety of correlations between protein evolution rate and these variables have been observed. The strongest connections by far were repeatedly seen between protein sequence evolution rate and the expression level of the respective gene. It has been hypothesized that this link is due to the selection for the robustness of the protein structure to mistranslation-induced misfolding that is particularly important for highly expressed proteins and is the dominant determinant of the sequence evolution rate. Results This work is an attempt to assess the relative contributions of protein domain structure and function, on the one hand, and expression level on the other hand, to the rate of sequence evolution. To this end, we performed a genome-wide analysis of the effect of the fusion of a pair of domains in multidomain proteins on the difference in the domain-specific evolutionary rates. The mistranslation-induced misfolding hypothesis would predict that, within multidomain proteins, fused domains, on average, should evolve at substantially closer rates than the same domains in different proteins because, within a mutlidomain protein, all domains are translated at the same rate. We performed a comprehensive comparison of the evolutionary rates of mammalian and plant protein domains

  2. Fourier Analysis and Structure Determination--Part III: X-ray Crystal Structure Analysis.

    Science.gov (United States)

    Chesick, John P.

    1989-01-01

    Discussed is single crystal X-ray crystal structure analysis. A common link between the NMR imaging and the traditional X-ray crystal structure analysis is reported. Claims that comparisons aid in the understanding of both techniques. (MVL)

  3. Dynamic Self-Stiffening and Structural Evolutions of Polyacrylonitrile/Carbon Nanotube Nanocomposites.

    Science.gov (United States)

    Li, Yinhui; Zhou, Pucha; An, Feng; Liu, Yaodong; Lu, Chunxiang

    2017-02-15

    The self-stiffening under external dynamic strain has been observed for some artificial materials, especially for nanocomposites. However, few systematic studies have been carried out on their structural evolutions, and the effect of the types of nanofillers was unclear. In this study, we used a semicrystalline polymer, polyacrylonitrile (PAN), and various types of carbon nanomaterials including C 60 , carbon nanotube (CNT), and graphene oxide (GO). An external uniaxial dynamic strain at small amplitude of 0.2% was applied on the prepared nanocomposite films. It was observed that PAN/CNT exhibited significant self-stiffening behavior, whereas PAN/GO showed no response. Systematic characterizations were performed to determine the structural evolutions of PAN/CNT film during dynamic strain testing, and it was found that the external dynamic strain not only induced the crystallization of PAN chains but also aligned CNT along the strain direction.

  4. SANS study of the structural evolution in NIPA/SA gel on dehydration

    CERN Document Server

    Sugiyama, M; Maeda, Y; Hara, K

    2002-01-01

    Mesoscopic structures of N-isopropylacryl-amide/sodium acrylate (NIPA/SA) gels with several water contents were investigated with a small-angle neutron scattering (SANS) method in order to make clear their structural evolution on dehydration. The evolution of the SANS profile with a decrease in the water content in the gel could be classified into three stages. In the beginning, there was no peak in the SANS profile except for the central part, which steadily intensified. With the further water dissipation, a side peak appeared at around 0.02 A sup - sup 1 , the intensity of which increased up to a certain water content and then decreased. These results indicate that the water dissipation in the NIPA/SA gel occurs inhomogeneously. (orig.)

  5. [Plant potyvirus evolution: the survey of the genetic structure of populations].

    Science.gov (United States)

    Ohshima, Kazusato

    2012-01-01

    The Potyvirus is the largest genus of the largest family of plant RNA viruses, the Potyviridae. The potyviruses infect not only dicotyledonous but also monocotyledonous plants. The potyvirus phylogeny shows that the genus probably originated from a virus of monocotyledonous plants and that it first diverged approximately 7250 years ago in Southwest Eurasia or North Africa. Turnip mosaic virus (TuMV) belongs to the genus Potyvirus and infects a wide range of plant species, most from the family Brassicaceae. TuMV is most studied a potyvirus species for molecular evolution and the genetic structure of populations. The use of computer programs for better understanding of the evolution and the genetic structures of populations of potyviruses and TuMV are illustrated.

  6. Granular flows on erodible layers: type and evolution of flow and deposit structures

    Science.gov (United States)

    Crosta, G.; De Blasio, F.; De Caro, M.; Volpi, G.; Frattini, P.

    2012-04-01

    The interaction of a fast moving landslide mass with the basal layer over which movement takes place has been discussed in previous contributions. Nevertheless, the evolution of the structures within the moving mass and the erodible layer are still to be described in detail (Hungr and Evans, 2004; Crosta et al., 1992, 2006, 2009, 2011; Dufresne et al., 2010; Mangeney et al., 2010) and modeling results (Crosta et al., 2006, 2009, 2011; Mangeney et al., 2010). We present some of the results from a campaign of laboratory experiments aimed at studying the evolution of a granular flow at the impact with and during the successive spreading over a cohesionless erodible layer. We performed these test to study the processes and to collect data and evidences to compare them with the results of numerical simulations and to verify capabilities of numerical codes. The laboratory setup consists of an inclined slope and an horizontal sector where release and transport, and deposition take place, respectively. Materials used for the tests are: a uniform rounded siliceous sand (Hostun sand; 0.125-0.5 mm) commonly adopted in lab tests because free of scale effects, and a gravel made of angular elements (12 mm in ave. size). Both the materials have been tested in dry conditions. Different slope angles have been tested (40, 45, 50, 55, 50, 66°) as well as different thicknesses of the erodible layer (0, 0.5, 1, 2 cm) and volumes of the released material (1.5, 3, 5, 9.6 liters). Tests have been monitored by means of a high speed camera and the pre- and post-failure geometries have been surveyed by means of a laser scanner. Deposit description allowed also the computation of volumes and the characterization of the different structures developed and frozen into the deposit. Experiments allowed us to observe the extreme processes occurring during the movement and the mise en place of the deposits. In particular, we observe the formation of a clear wave-like feature developing during the

  7. From Microactions to Macrostructure and Back : A Structurational Approach to the Evolution of Organizational Networks

    NARCIS (Netherlands)

    Whitbred, Robert; Fonti, Fabio; Steglich, Christian; Contractor, Noshir

    Structuration theory (ST) and network analysis are promising approaches for studying the emergence of communication networks. We offer a model that integrates the conceptual richness of structuration with the precision of relevant concepts and mechanisms offered from communication network research.

  8. Measurement of reaction rates of interest in stellar structure and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Terrasi, F.; D`Onofrio, A. [Dipt. di Scienze Ambientali, Seconda Univ. di Napoli, Caserta (Italy)]|[INFN, Napoli (Italy); Campajola, L.; Imbriani, G. [INFN, Napoli (Italy)]|[Dipt. di Scienze Fisiche, Univ. Federico II, Napoli (Italy); Gialanella, L. [INFN, Napoli (Italy)]|[Dipt. di Scienze Fisiche, Univ. Federico II, Napoli (Italy)]|[Inst. fuer Experimentalphysik III, Ruhr-Univ. Bochum, Bochum (Germany); Greife, U.; Rolfs, C.; Strieder, F.; Trautvetter, H.P. [Inst. fuer Experimentalphysik III, Ruhr-Univ. Bochum, Bochum (Germany); Roca, V.; Romano, M. [INFN, Napoli (Italy)]|[Dipt. di Scienze Fisiche, Univ. Federico II, Napoli (Italy); Straniero, O. [Osservatorio Astronomico di Collurania, Teramo (Italy)

    1998-06-01

    Accurate determinations of reaction rates at astrophysical energies are very important in stellar structure and evolution studies. The cases of two key reactions, namely {sup 7}Be(p,{gamma}){sup 8}B and {sup 12}C({alpha},{gamma}){sup 16}O are discussed, both from the point of view of their astrophysical interest and of the experimental difficulties in the measurement of their cross section. (orig.)

  9. Directed evolution of the periodic table: probing the electronic structure of late actinides.

    Science.gov (United States)

    Marsh, M L; Albrecht-Schmitt, T E

    2017-07-25

    Recent investigations of the coordination chemistry and physical properties of berkelium (Z = 97) and californium (Z = 98) have revealed fundamental differences between post-curium elements and lighter members of the actinide series. This review highlights these developments and chronicles key findings and concepts from the last half-century that have helped usher in a new understanding of the evolution of electronic structure in the periodic table.

  10. Structural evolution of epitaxial SrCoOx films near topotactic phase transition

    OpenAIRE

    Hyoungjeen Jeen; Ho Nyung Lee

    2015-01-01

    Control of oxygen stoichiometry in complex oxides via topotactic phase transition is an interesting avenue to not only modifying the physical properties, but utilizing in many energy technologies, such as energy storage and catalysts. However, detailed structural evolution in the close proximity of the topotactic phase transition in multivalent oxides has not been much studied. In this work, we used strontium cobaltites (SrCoOx) epitaxially grown by pulsed laser epitaxy (PLE) as a model syste...

  11. Cultural evolution in more than two dimensions: distinguishing social learning biases and identifying payoff structures.

    Science.gov (United States)

    Mesoudi, Alex

    2014-02-01

    Bentley et al.'s two-dimensional conceptual map is complementary to cultural evolution research that has sought to explain population-level cultural dynamics in terms of individual-level behavioral processes. Here, I qualify their scheme by arguing that different social learning biases should be treated distinctly, and that the transparency of decisions is sometimes conflated with the actual underlying payoff structure of those decisions.

  12. Morphometric analysis of El Salvador Fault Zone. Implications to the tectonic evolution. Central America.

    Science.gov (United States)

    Alonso-Henar, Jorge; Jesús Martínez-Díaz, José; Álvarez-Gómez, José Antonio

    2013-04-01

    It is considered that the study of the recent topography development, and the use of geomorphological indexes are good tools for the quantification of the active tectonics. We have used quantitative geomorphology in order to improve our understanding of the recent activity and tectonic evolution of the El Salvador Fault Zone (ESFZ); an E-W oriented strike-slip fault zone that extends 150 km through El Salvador (Martínez-Díaz et al. 2004). Previous studies propose a transtensive tectonic regime at the Central America Volcanic Arc in El Salvador, which induces relative vertical motions on the faults within El Salvador Fault Zone (i.e. Álvarez-Gómez et al., 2008, Cáceres et al. 2005,). This relative vertical displacement can be quantified with the use of hypsometry as a geomorphological character. The morphometric analysis done contributes to a better understanding of the ESFZ. We have defined km scale tectonic block relative displacements that may be useful to constrain the strain distribution along the ESFZ, length of segments with homogeneous vertical movements and lateral relay of active structures. This study supports the hypothesis of a recent migration in the maximum shortening direction, and the accomodation of the current deformation through the reactivation of pre-existing structures inherited from a previous tectonic frame. A similar tectonic evolution as described Weinberg (1992) in Nicaragua, is interpreted from the results of this study.

  13. Monitoring Data-Structure Evolution in Distributed Message-Passing Programs

    Science.gov (United States)

    Sarukkai, Sekhar R.; Beers, Andrew; Woodrow, Thomas S. (Technical Monitor)

    1996-01-01

    Monitoring the evolution of data structures in parallel and distributed programs, is critical for debugging its semantics and performance. However, the current state-of-art in tracking and presenting data-structure information on parallel and distributed environments is cumbersome and does not scale. In this paper we present a methodology that automatically tracks memory bindings (not the actual contents) of static and dynamic data-structures of message-passing C programs, using PVM. With the help of a number of examples we show that in addition to determining the impact of memory allocation overheads on program performance, graphical views can help in debugging the semantics of program execution. Scalable animations of virtual address bindings of source-level data-structures are used for debugging the semantics of parallel programs across all processors. In conjunction with light-weight core-files, this technique can be used to complement traditional debuggers on single processors. Detailed information (such as data-structure contents), on specific nodes, can be determined using traditional debuggers after the data structure evolution leading to the semantic error is observed graphically.

  14. Structural analysis in medical imaging

    International Nuclear Information System (INIS)

    Dellepiane, S.; Serpico, S.B.; Venzano, L.; Vernazza, G.

    1987-01-01

    The conventional techniques in Pattern Recognition (PR) have been greatly improved by the introduction of Artificial Intelligence (AI) approaches, in particular for knowledge representation, inference mechanism and control structure. The purpose of this paper is to describe an image understanding system, based on the integrated approach (AI - PR), developed in the author's Department to interpret Nuclear Magnetic Resonance (NMR) images. The system is characterized by a heterarchical control structure and a blackboard model for the global data-base. The major aspects of the system are pointed out, with particular reference to segmentation, knowledge representation and error recovery (backtracking). The eye slices obtained in the case of two patients have been analyzed and the related results are discussed

  15. Structural Analysis of Natural Products

    Czech Academy of Sciences Publication Activity Database

    Přichystal, Jakub; Schug, K. A.; Lemr, Karel; Novák, Jiří; Havlíček, Vladimír

    2016-01-01

    Roč. 88, č. 21 (2016), s. 10338-10346 ISSN 0003-2700 R&D Projects: GA MŠk(CZ) LO1509; GA MŠk(CZ) LH14064; GA ČR(CZ) GA16-20229S Institutional support: RVO:61388971 Keywords : IONIZATION-MASS-SPECTROMETRY * BIOSYNTHETIC GENE CLUSTERS * STRUCTURE ELUCIDATION Subject RIV: EE - Microbiology, Virology Impact factor: 6.320, year: 2016

  16. Reliability analysis and assessment of structural systems

    International Nuclear Information System (INIS)

    Yao, J.T.P.; Anderson, C.A.

    1977-01-01

    The study of structural reliability deals with the probability of having satisfactory performance of the structure under consideration within any specific time period. To pursue this study, it is necessary to apply available knowledge and methodology in structural analysis (including dynamics) and design, behavior of materials and structures, experimental mechanics, and the theory of probability and statistics. In addition, various severe loading phenomena such as strong motion earthquakes and wind storms are important considerations. For three decades now, much work has been done on reliability analysis of structures, and during this past decade, certain so-called 'Level I' reliability-based design codes have been proposed and are in various stages of implementation. These contributions will be critically reviewed and summarized in this paper. Because of the undesirable consequences resulting from the failure of nuclear structures, it is important and desirable to consider the structural reliability in the analysis and design of these structures. Moreover, after these nuclear structures are constructed, it is desirable for engineers to be able to assess the structural reliability periodically as well as immediately following the occurrence of severe loading conditions such as a strong-motion earthquake. During this past decade, increasing use has been made of techniques of system identification in structural engineering. On the basis of non-destructive test results, various methods have been developed to obtain an adequate mathematical model (such as the equations of motion with more realistic parameters) to represent the structural system

  17. Quantifying Selective Pressures Driving Bacterial Evolution Using Lineage Analysis

    Science.gov (United States)

    Lambert, Guillaume; Kussell, Edo

    2015-01-01

    Organisms use a variety of strategies to adapt to their environments and maximize long-term growth potential, but quantitative characterization of the benefits conferred by the use of such strategies, as well as their impact on the whole population's rate of growth, remains challenging. Here, we use a path-integral framework that describes how selection acts on lineages—i.e., the life histories of individuals and their ancestors—to demonstrate that lineage-based measurements can be used to quantify the selective pressures acting on a population. We apply this analysis to Escherichia coli bacteria exposed to cyclical treatments of carbenicillin, an antibiotic that interferes with cell-wall synthesis and affects cells in an age-dependent manner. While the extensive characterization of the life history of thousands of cells is necessary to accurately extract the age-dependent selective pressures caused by carbenicillin, the same measurement can be recapitulated using lineage-based statistics of a single surviving cell. Population-wide evolutionary pressures can be extracted from the properties of the surviving lineages within a population, providing an alternative and efficient procedure to quantify the evolutionary forces acting on a population. Importantly, this approach is not limited to age-dependent selection, and the framework can be generalized to detect signatures of other trait-specific selection using lineage-based measurements. Our results establish a powerful way to study the evolutionary dynamics of life under selection and may be broadly useful in elucidating selective pressures driving the emergence of antibiotic resistance and the evolution of survival strategies in biological systems.

  18. An empirical formulation to describe the evolution of the high burnup structure

    Science.gov (United States)

    Lemes, Martín; Soba, Alejandro; Denis, Alicia

    2015-01-01

    In the present work the behavior of fuel pellets for LWR power reactors in the high burnup range (average burnup higher than about 45 MWd/kgU) is analyzed. For extended irradiation periods, a considerable Pu concentration is reached in the pellet periphery (rim zone), that contributes to local burnup. Gradually, a new microstructure develops in that ring, characterized by small grains and large pores as compared with those of the original material. In this region Xe is absent from the solid lattice (although it continues to be dissolved in the rest of the pellet). The porous microstructure in the pellet edge causes local changes in the mechanical and thermal properties, thus affecting the overall fuel behavior. It is generally accepted that the evolution of porosity in the high burnup structure (HBS) is determinant of the retention capacity of the fission gases rejected from the fuel matrix. This is the reason why, during the latest years a considerable effort has been devoted to characterizing the parameters that influence porosity. Although the mechanisms governing the microstructural transformation have not been completely elucidated yet, some empirical expressions can be given, and this is the intention of the present work, for representing the main physical parameters. Starting from several works published in the open literature, some mathematical expressions were developed to describe the behavior and progress of porosity at local burnup values ranging from 60 to 300 MWd/kgU. The analysis includes the interactions of different orders between pores, the growth of the pore radius by capturing vacancies, the evolution of porosity, pore number density and overpressure within the closed pores, the inventory of fission gas dissolved in the matrix and retained in the pores. The model is mathematically expressed by a system of non-linear differential equations. In the present work, results of this calculation scheme are compared with experimental data available in

  19. Climate-dependent evolution of Antarctic ectotherms: An integrative analysis

    Science.gov (United States)

    Pörtner, Hans O.

    2006-04-01

    The paper explores the climate-dependent evolution of marine Antarctic fauna and tries to identify key mechanisms involved as well as the driving forces that have caused the physiological and life history characteristics observed today. In an integrative approach it uses the recent concept of oxygen and capacity limited thermal tolerance to identify potential links between molecular, cellular, whole-organism, and ecological characteristics of marine animal life in the Antarctic. As a generalized pattern, minimization of baseline energy costs, for the sake of maximized growth in the cold, appears as one over-arching principle shaping the evolution and functioning of Antarctic marine ectotherms. This conclusion is supported by recent comparisons with (sub-) Arctic ectotherms, where elevated levels of energy turnover result at unstable, including cold temperatures, and are related to wide windows of thermal tolerance and associated metabolic features. At biochemical levels, metabolic regulation at low temperatures in general, is supported by the cold compensation of enzyme kinetic parameters like substrate affinities and turnover numbers, through minute structural modifications of the enzyme molecule. These involve a shift in protein folding, sometimes supported by the replacement of individual amino acids. The hypothesis is developed that efficient metabolic regulation at low rates in Antarctic marine stenotherms occurs through high mitochondrial densities at low capacities and possibly enhanced levels of Arrhenius activation energies or activation enthalpies. This contrasts the more costly patterns of metabolic regulation at elevated rates in cold-adapted eurytherms. Energy savings in Antarctic ectotherms, largely exemplified in fish, typically involve low-cost, diffusive oxygen distribution due to high density of lipid membranes, loss of haemoglobin, myoglobin and the heat shock response, reduced anaerobic capacity, large myocytes with low ion exchange activities

  20. Structure analysis - chiromancy of the rock

    International Nuclear Information System (INIS)

    Huber, A.; Huber, M.

    1989-01-01

    The reader may initially be surprised by a comparison between structure analysis and palmistry which is, in effect, a comparison between a scientific research method on the one hand and art which is equated with magical powers on the other. In the figurative sense, however, these two fields have some points in common which should help us to obtain a first impression of the nature of geological structure analysis. Chiromancy uses the lines and the form of the hand to predict the character and the future of the person in question. In the same way, geologists use rocks and rock forms to obtain information on structure and behaviour of different formations. Structure analysis is a specialised field of geological investigation in which traces of deformation are interpreted as expressions of rockforming forces. This article discusses how and why the character of a rock formation as well as its past, present and even future behaviour can be determined using structure analysis. (author) 11 figs

  1. Regional evolution of geological structure in south China and U mineralization

    International Nuclear Information System (INIS)

    Chen Guoda; Kang Zili; Shen Jinrui; Jin Yushu

    1992-01-01

    This paper states the development laws of regional geological structure of South China and its controlling effect on uranium deposit evolution, and the characteristics of rich uranium formation in different periods of geo-history are analysed. It also discusses the relationship between the distribution of time and space and tectonic structure and environmental vicissitudes. The rock-magma activities-the strong formation of the Diwa Era is of great significance to the formation of uranium deposits within the region, especially to the formation of a series of multi-genesis polygene uranium deposits which are a potential direction in which to look for minerals within the region

  2. Structural analysis consultation using artificial intelligence

    Science.gov (United States)

    Melosh, R. J.; Marcal, P. V.; Berke, L.

    1978-01-01

    The primary goal of consultation is definition of the best strategy to deal with a structural engineering analysis objective. The knowledge base to meet the need is designed to identify the type of numerical analysis, the needed modeling detail, and specific analysis data required. Decisions are constructed on the basis of the data in the knowledge base - material behavior, relations between geometry and structural behavior, measures of the importance of time and temperature changes - and user supplied specifics characteristics of the spectrum of analysis types, the relation between accuracy and model detail on the structure, its mechanical loadings, and its temperature states. Existing software demonstrated the feasibility of the approach, encompassing the 36 analysis classes spanning nonlinear, temperature affected, incremental analyses which track the behavior of structural systems.

  3. Analysis of the Evolution of Financial Indicators for the Period 2004-2014 Transgaz SA

    OpenAIRE

    Andreea-Gabriela Baltac

    2015-01-01

    This article highlights the financial analysis of the evolution of a company through the key indicators involved. For this we watched a firm financial evolution of Romania and its main financial over 11 years. The study investigated virtually throughout the entity was based on an analysis of the financial indicators in the period 2004-2014 in Transgaz S.A. The objectives of this analysis are to determine the main financial indicators that lead to obtaining high economic performance. I used th...

  4. Robustness Analysis of Timber Truss Structure

    DEFF Research Database (Denmark)

    Rajčić, Vlatka; Čizmar, Dean; Kirkegaard, Poul Henning

    2010-01-01

    The present paper discusses robustness of structures in general and the robustness requirements given in the codes. Robustness of timber structures is also an issues as this is closely related to Working group 3 (Robustness of systems) of the COST E55 project. Finally, an example of a robustness...... evaluation of a widespan timber truss structure is presented. This structure was built few years ago near Zagreb and has a span of 45m. Reliability analysis of the main members and the system is conducted and based on this a robustness analysis is preformed....

  5. 3D Evolution of Turbulent Flow Structures in Taylor-Couette

    Science.gov (United States)

    Tokgoz, Sedat; Elsinga, Gerrit E.; Westerweel, Jerry

    2013-11-01

    In this study, we use high-speed tomographic PIV to investigate the evolution of turbulent flow structures in Taylor-Couette flow. High-speed tomographic PIV enables fully volumetric time-resolved measurements and is well-suited for this purpose. Presently, the turbulent flow is created by exact counter-rotation of the cylinders (Rei = - Reo , RΩ = 0 . 0), where the wall velocities are the same with opposite sign. Under these circumstances, the mean flow is zero in the bulk. Results indicate that the structures still advance in one direction despite the zero mean. However, the observation time for the flow structures is still at least one order magnitude longer than in the boundary layer flows, which were considered before. Results also revealed the presence of azimuthal velocity streaks. It is found that the intense vortical structures are mostly located in the shear layer between these streaks. Different events regarding the evolution of the vortical structures, such as stretching and break-up of vortices, are observed.

  6. Structural evolutions of supported Co clusters with different configurations on the Cu(010) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guojian; Sui, Xudong; Wu, Chun; Wang, Qiang, E-mail: wangq@mail.neu.edu.cn; Wang, Kai; He, Jicheng

    2015-12-04

    Structural evolutions of Co{sub 561} clusters supported on the Cu(010) substrate were studied by molecular dynamics simulation using an embedded atom method. Energy, snapshot, pair distribution function and epitaxial factor were used to analyze the effects of supported position, configuration and temperature on the structural evolutions. It is found that the energy of the cluster changes significantly with varying the supported position and the original configuration. The most stable supported position is (111) facet. As a function of configuration the stability decreases in the order: icosahedron > truncated octahedron > decahedron > cuboctahedron > sphere. Supported (111) facet changes to stack along the (100) of substrate. Epitaxial growth on the substrate occurs for all configurations. The epitaxial temperature and the amount of epitaxial atoms are related to the configuration. The epitaxial growth is adverse to the stability of the cluster, while the epitaxy has no effect on the crystal structure of the supported cluster. The energy of the cluster is reduced by the epitaxial growth and atomic penetration into the substrate but is enhanced by the distortion of the cluster on the substrate. - Highlights: • Stability of supported cluster is adverse to the epitaxial growth. • Stable supported position and structure are respectively (111) facet and icosahedron. • Supported (111) facet changes to stack along the (100) of the substrate. • Epitaxial temperature and the magnitude are related to the cluster structure.

  7. Late Cretaceous - recent lithosphere scale evolution of Turkey: linking the crustal surface evolution to the structure of the mantle

    Science.gov (United States)

    Bartol, J.; Govers, R. M. A.; Wortel, M. J. R.

    2015-12-01

    Central Anatolia (Central Turkey) possesses all the characteristics of a plateau. It experienced a period of rapid and substantial uplift (late Miocene, ˜8 Ma) while significant crustal shortening did not occur. Similar to other plateaus, the presence of volcanic ash and tuff within the sediments suggest that uplift was preceded by widespread volcanism (˜14-9Ma). The lithospheric context of these events is, however, unknown. For the Eastern Anatolian plateau, similar events have been attributed to southward retread followed by slab break-off of the northern Neotethys slab. Recent tomographic results indicate that this northern Neotethys slab extended beneath both the Eastern and Central Anatolian plateau prior to late Miocene delamination and possibly even beneath western Anatolia prior to the Eocene (?). We propose a new lithospheric scenario for the regional evolution for the Aegean-Anatolia-Near East region that combines a recent compilation of surface geology data with the structure of the upper mantle imaged with tomography. In our new scenario for the evolution of the Aegean-Anatolia-Near East region, a single continuous subduction zone south of the Pontides (Izmir - Ankara - Erzincan crustal suture zone) accommodated the Africa - Eurasia convergence until the end of the late Cretaceous. In the Late Cretaceous - Eocene the northern Neotethys Ocean closed followed by Anatolide - Taurides (south) and Pontides (north) continental collision along the Izmir - Ankara - Erzincan crustal suture zone. While the trench jumped to the south of Anatolide - Taurides terrane, subduction continued beneath the Izmir-Ankara-Erzincan suture where the northern Neotethys slab continued to sink into the deeper mantle. In the early Miocene (˜20-15Ma), the northern Neotethys slab started to retreat southward towards the trench, resulting in delamination of the lithospheric mantle. The last part of (early Miocene - recent) our scenario is testable. We use a coupled thermal

  8. Structural Analysis Algorithms for Nanomaterials

    DEFF Research Database (Denmark)

    Larsen, Peter Mahler

    -strain interfaces. The stable, low-energy interfaces which are found as a result are intended for use in the design and construction of topological superconductors, which have important applications in quantum computing. Cluster expansion models are used to nd ground-state structures in gold-silver nanoparticles......, which are used in a variety of catalysis processes. In addition to this concrete application, theoretical methods are developed for the optimal construction of cluster expansion models, the exact determination of ground states in a large model, and the exhaustive determination of all possible ground...... states in a small model. Lastly, a method for nearly-optimal sampling of orientations is presented. Whilst this has many applications in science and engineering, the use-case described here is the indexing of diffraction patterns for experimental materials characterization. Signicantly improved sampling...

  9. Computer-aided structure analysis

    International Nuclear Information System (INIS)

    Szalontai, G.; Simon, Z.; Csapo, Z.; Farkas, M.; Pfeifer, Gy.

    1980-01-01

    The results obtained from the computer-aided interpretation of 13 C NMR and IR spectra using the artificial intelligence approach are presented. In its present state the output of the system is a list of functional groups which are resonable candidates for the final structural isomers. The input requires empirical formula, 13 C NMR data (off resonance data also) and IR spectral data. The confirmation of the presence of a functional group is based on comparison of the experimental data with the spectral properties of functional groups stored in a property matrix. If the molecular weight of the compounds studied is less or equal 500, the output contains usually 1.5-2.5 times more groups than really present, in most cases without the loss of the real ones. (author)

  10. Structural analysis of fuel handling systems

    International Nuclear Information System (INIS)

    Lee, L.S.S.

    1996-01-01

    The purpose of this paper has three aspects: (i) to review 'why' and 'what' types of structural analysis, testing and report are required for the fuel handling systems according to the codes, or needed for design of a product, (ii) to review the input requirements for analysis and the analysis procedures, and (iii) to improve the communication between the analysis and other elements of the product cycle. The required or needed types of analysis and report may be categorized into three major groups: (i) Certified Stress Reports for design by analysis, (ii) Design Reports not required for certification and registration, but are still required by codes, and (iii) Design Calculations required by codes or needed for design. Input requirements for structural analysis include: design, code classification, loadings, and jurisdictionary boundary. Examples of structural analysis for the fueling machine head and support structure are given. For improving communication between the structural analysis and the other elements of the product cycle, some areas in the specification of design requirements and load rating are discussed. (author). 6 refs., 1 tab., 4 figs

  11. Evolution of local atomic structure during solidification of Al2Au liquid: An ab initio study

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, L H; Lou, H B; Wang, X D; Debela, T T; Cao, Q P; Zhang, D X; Wang, S Y; Wang, C Z; Jiang, J Z

    2014-04-01

    The local atomic structure evolution in Al2Au alloy during solidification from 2000 K to 400 K was studied by ab initio molecular dynamics simulations and analyzed using the structure factor, pair correlation functions, bond angle distributions, the Honeycutt-Anderson (HA) index and Voronoi tessellation methods. It was found that the icosahedral-like clusters are negligible in the Al2Au stable liquid and supercooled liquid states, and the most abundant clusters are those having HA indices of 131 and 120 or Voronoi indices of < 0,4,4,0 >, < 0,3, 6,0 > and < 0,4,4,2 > with coordination numbers of 8, 9 and 10, respectively. These clusters are similar to the local atomic structures in the CaF2-type Al2Au crystal, revealing the existence of structure heredity between liquid and crystalline phase in Al2Au alloy. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. The evolution of plant secretory structures and emergence of terpenoid chemical diversity.

    Science.gov (United States)

    Lange, Bernd Markus

    2015-01-01

    Secretory structures in terrestrial plants appear to have first emerged as intracellular oil bodies in liverworts. In vascular plants, internal secretory structures, such as resin ducts and laticifers, are usually found in conjunction with vascular bundles, whereas subepidermal secretory cavities and epidermal glandular trichomes generally have more complex tissue distribution patterns. The primary function of plant secretory structures is related to defense responses, both constitutive and induced, against herbivores and pathogens. The ability to sequester secondary (or specialized) metabolites and defense proteins in secretory structures was a critical adaptation that shaped plant-herbivore and plant-pathogen interactions. Although this review places particular emphasis on describing the evolution of pathways leading to terpenoids, it also assesses the emergence of other metabolite classes to outline the metabolic capabilities of different plant lineages.

  13. NAPS: Network Analysis of Protein Structures

    Science.gov (United States)

    Chakrabarty, Broto; Parekh, Nita

    2016-01-01

    Traditionally, protein structures have been analysed by the secondary structure architecture and fold arrangement. An alternative approach that has shown promise is modelling proteins as a network of non-covalent interactions between amino acid residues. The network representation of proteins provide a systems approach to topological analysis of complex three-dimensional structures irrespective of secondary structure and fold type and provide insights into structure-function relationship. We have developed a web server for network based analysis of protein structures, NAPS, that facilitates quantitative and qualitative (visual) analysis of residue–residue interactions in: single chains, protein complex, modelled protein structures and trajectories (e.g. from molecular dynamics simulations). The user can specify atom type for network construction, distance range (in Å) and minimal amino acid separation along the sequence. NAPS provides users selection of node(s) and its neighbourhood based on centrality measures, physicochemical properties of amino acids or cluster of well-connected residues (k-cliques) for further analysis. Visual analysis of interacting domains and protein chains, and shortest path lengths between pair of residues are additional features that aid in functional analysis. NAPS support various analyses and visualization views for identifying functional residues, provide insight into mechanisms of protein folding, domain-domain and protein–protein interactions for understanding communication within and between proteins. URL:http://bioinf.iiit.ac.in/NAPS/. PMID:27151201

  14. Structural Dynamics and Data Analysis

    Science.gov (United States)

    Luthman, Briana L.

    2013-01-01

    This project consists of two parts, the first will be the post-flight analysis of data from a Delta IV launch vehicle, and the second will be a Finite Element Analysis of a CubeSat. Shock and vibration data was collected on WGS-5 (Wideband Global SATCOM- 5) which was launched on a Delta IV launch vehicle. Using CAM (CAlculation with Matrices) software, the data is to be plotted into Time History, Shock Response Spectrum, and SPL (Sound Pressure Level) curves. In this format the data is to be reviewed and compared to flight instrumentation data from previous flights of the same launch vehicle. This is done to ensure the current mission environments, such as shock, random vibration, and acoustics, are not out of family with existing flight experience. In family means the peaks on the SRS curve for WGS-5 are similar to the peaks from the previous flights and there are no major outliers. The curves from the data will then be compiled into a useful format so that is can be peer reviewed then presented before an engineering review board if required. Also, the reviewed data will be uploaded to the Engineering Review Board Information System (ERBIS) to archive. The second part of this project is conducting Finite Element Analysis of a CubeSat. In 2010, Merritt Island High School partnered with NASA to design, build and launch a CubeSat. The team is now called StangSat in honor of their mascot, the mustang. Over the past few years, the StangSat team has built a satellite and has now been manifested for flight on a SpaceX Falcon 9 launch in 2014. To prepare for the final launch, a test flight was conducted in Mojave, California. StangSat was launched on a Prospector 18D, a high altitude rocket made by Garvey Spacecraft Corporation, along with their sister satellite CP9 built by California Polytechnic University. However, StangSat was damaged during an off nominal landing and this project will give beneficial insights into what loads the CubeSat experienced during the crash

  15. Binder-induced surface structure evolution effects on Li-ion battery performance

    Science.gov (United States)

    Rezvani, S. J.; Pasqualini, M.; Witkowska, A.; Gunnella, R.; Birrozzi, A.; Minicucci, M.; Rajantie, H.; Copley, M.; Nobili, F.; Di Cicco, A.

    2018-03-01

    A comparative investigation on binder induced chemical and morphological evolution of Li4Ti5O12 electrodes was performed via X-ray photoemission spectroscopy, scanning electron microscopy, and electrochemical measurements. Composite electrodes were obtained using three different binders (PAA, PVdF, and CMC) with 80:10:10 ratio of active material:carbon:binder. The electrochemical performances of the electrodes, were found to be intimately correlated with the evolution of the microstructure of the electrodes, probed by XPS and SEM analysis. Our analysis shows that the surface chemistry, thickness of the passivation layers and the morphology of the electrodes are strongly dependent on the type of binders that significantly influence the electrochemical properties of the electrodes. These results point to a key role played by binders in optimization of the battery performance and improve our understanding of the previously observed and unexplained electrochemical properties of these electrodes.

  16. Evolution of kinetically controlled In-induced surface structure on Si(5 5 7) surface

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Amit Kumar Singh [Physics of Energy Harvesting, (CSIR-NPL), Dr. K.S. Krishnan Road, New Delhi 110012 (India); Department of Physics, JMI, New Delhi 110025 (India); Eldose, Nirosh M.; Mishra, Monu [Physics of Energy Harvesting, (CSIR-NPL), Dr. K.S. Krishnan Road, New Delhi 110012 (India); Niazi, Asad; Nair, Lekha [Department of Physics, JMI, New Delhi 110025 (India); Gupta, Govind, E-mail: govind@nplindia.org [Physics of Energy Harvesting, (CSIR-NPL), Dr. K.S. Krishnan Road, New Delhi 110012 (India)

    2014-09-30

    Highlights: • Evolution of In induced superstructures on Si(5 5 7) surface during RT and HT adsorption/desorption process. • Kinetics is governed by substrate temperature which exhibits various growth modes (FM, SK, VB) under different conditions. • Strain relaxation play significant role in the commencement of desorption/rearrangement of atoms. • A consolidated phase diagram of In/Si(5 5 7) interface has been reported with new √3 × √3-R30° and 4 × 1 phases. - Abstract: This paper introduces issue of kinetically controlled and temperature driven superstructural phase transition of Indium (In) on atomically clean high index Si(5 5 7)-7 × 1 surface. Auger electron spectroscopy analysis reveals that at room-temperature (RT) with a controlled incident flux of 0.002 ML/s; In overlayers evolve through the Frank-van der Merwe growth mode and yield a (1 × 1) diffraction pattern for coverage ≥1 ML. For substrate temperature <500°C, growth of In follows Stranski–Krastanov growth mode while for temperature >500°C island growth is observed. On annealing the In/Si(5 5 7) interface in the temperature range 250–340°C, clusters to two dimensional (2D) layer transformation on top of a stable monolayer is predominated. In-situ RT and HT adsorption and thermal desorption phenomena revealed the formation of coverage and temperature dependent thermally stable In induced superstructural phases such as (4 × 1) at 0.5 ML (520°C), (√3 × √3-R30°) at 0.3 ML (560°C) and (7 × 7) at 0.1 ML (580°C). These indium induced superstructures could be utilized as potential substrate for the growth of various exotic 1D/2D structures.

  17. Structure and Evolution of the Smith-Magenis Syndrome Repeat Gene Clusters, SMS-REPs

    Science.gov (United States)

    Park, Sung-Sup; Stankiewicz, Paweł; Bi, Weimin; Shaw, Christine; Lehoczky, Jessica; Dewar, Ken; Birren, Bruce; Lupski, James R.

    2002-01-01

    An ∼4-Mb genomic segment on chromosome 17p11.2, commonly deleted in patients with the Smith-Magenis syndrome (SMS) and duplicated in patients with dup(17)(p11.2p11.2) syndrome, is flanked by large, complex low-copy repeats (LCRs), termed proximal and distal SMS-REP. A third copy, the middle SMS-REP, is located between them. SMS-REPs are believed to mediate nonallelic homologous recombination, resulting in both SMS deletions and reciprocal duplications. To delineate the genomic structure and evolutionary origin of SMS-REPs, we constructed a bacterial artificial chromosome/P1 artifical chromosome contig spanning the entire SMS region, including the SMS-REPs, determined its genomic sequence, and used fluorescence in situ hybridization to study the evolution of SMS-REP in several primate species. Our analysis shows that both the proximal SMS-REP (∼256 kb) and the distal copy (∼176 kb) are located in the same orientation and derived from a progenitor copy, whereas the middle SMS-REP (∼241 kb) is inverted and appears to have been derived from the proximal copy. The SMS-REP LCRs are highly homologous (>98%) and contain at least 14 genes/pseudogenes each. SMS-REPs are not present in mice and were duplicated after the divergence of New World monkeys from pre-monkeys ∼40–65 million years ago. Our findings potentially explain why the vast majority of SMS deletions and dup(17)(p11.2p11.2) occur at proximal and distal SMS-REPs and further support previous observations that higher-order genomic architecture involving LCRs arose recently during primate speciation and may predispose the human genome to both meiotic and mitotic rearrangements. PMID:11997339

  18. Dynamic analysis and design of offshore structures

    CERN Document Server

    Chandrasekaran, Srinivasan

    2015-01-01

    This book  attempts to provide readers with an overall idea of various types of offshore platform geometries. It covers the various environmental loads encountered by these structures, a detailed description of the fundamentals of structural dynamics in a class-room style, estimate of damping in offshore structures and their applications in the preliminary analysis and design. Basic concepts of structural dynamics are emphasized through simple illustrative examples and exercises. Design methodologies and guidelines, which are FORM based concepts are explained through a few applied example structures. Each chapter also has tutorials and exercises for self-learning. A dedicated chapter on stochastic dynamics will help the students to extend the basic concepts of structural dynamics to this advanced domain of research. Hydrodynamic response of offshore structures with perforated members is one of the recent research applications, which is found to be one of the effective manner of retrofitting offshore structur...

  19. Pedestal structure and inter-ELM evolution for different main ion species in ASDEX Upgrade

    Science.gov (United States)

    Laggner, F. M.; Wolfrum, E.; Cavedon, M.; Mink, F.; Bernert, M.; Dunne, M. G.; Schneider, P. A.; Kappatou, A.; Birkenmeier, G.; Fischer, R.; Willensdorfer, M.; Aumayr, F.

    2017-05-01

    In tokamak plasmas with different main ion species, a change in confinement occurs, known as the isotope effect. Experiments comparing hydrogen (H), deuterium (D), and helium (4He) plasmas have been performed to identify processes that define the pedestal structure and evolution in between the crashes of edge localized modes (ELMs). The pedestal top electron densities and temperatures have been matched to compare the pedestal shape and stability. In the D and H discharges, the pedestal electron temperature profiles do not differ, whereas the density profile in H has shallower gradients. Furthermore, the heat flux across the pedestal in H is roughly a factor of two higher than in D. In 4He plasmas at similar stored energy, the pedestal top electron density is roughly a factor of 1.5 larger than in the references owing to the larger effective charge. The peeling-ballooning theory, which is independent of the main ion species mass, can sufficiently describe the pedestal stability in the hydrogenic plasmas. The inter-ELM pedestal evolution has the same sequence of recovery phases for all investigated species, giving evidence that similar mechanisms are acting in the pedestals. This is further supported by a similar evolution of the inter-ELM magnetic signature and the corresponding toroidal structure.

  20. Semantic Antinomies and Deep Structure Analysis

    Science.gov (United States)

    Zuber, Ryszard

    1975-01-01

    This article discusses constructions known as semantic antinomies, that is, the paradoxical results of false presuppositions, and how they can be dealt with by means of deep structure analysis. See FL 508 186 for availability. (CLK)

  1. Comprehensive risk analysis for structure type selection.

    Science.gov (United States)

    2010-04-01

    Optimization of bridge selection and design traditionally has been sought in terms of the finished structure. This study presents a : more comprehensive risk-based analysis that includes user costs and accidents during the construction phase. Costs f...

  2. First steps in eukaryogenesis: Physical phenomena in the origin and evolution of chromosome structure

    International Nuclear Information System (INIS)

    Chela Flores, J.

    1995-01-01

    Our present understanding of the origin and evolution of chromosomes differs considerably from current understanding of the origin and evolution of the cell itself. Chromosome origins have been less prominent in research, as the emphasis has not shifted so far appreciably from the phenomenon of primeval nucleic acid encapsulation to that of the origin of gene organization, expression, and regulation. In this work we discuss some reasons why preliminary steps in this direction are being taken. We have been led to examine properties that have contributed to raise the ancestral prokaryotic programmes to a level where we can appreciate in eukaryotes a clear departure from earlier themes in the evolution of the cell from the last common ancestor. We shift our point of view from evolution of cell morphology to the point of view of the genes. In particular, we focus attention on possible physical bases for the way transmission of information has evolved in eukaryotes, namely, the inactivation of whole chromosomes. The special case of inactivation of the X chromosome in mammals is discussed, paying particular attention to the physical process of the spread of X inactivation in monotremes (platypus and echidna.) When experimental data is unavailable some theoretical analysis is possible based on the idea that in certain cases collective phenomena in genetics, rather than chemical detail, are better correlates of complex chemical processes. (author). Abstract only

  3. First steps in eukaryogenesis: Physical phenomena in the origin and evolution of chromosome structure

    International Nuclear Information System (INIS)

    Chela Flores, J.

    1995-08-01

    Our present understanding of the origin and evolution of chromosomes differs considerably from current understanding of the origin and evolution of the cell itself. Chromosome origins have been less prominent in research, as the emphasis has not shifted so far appreciably from the phenomenon of primeval nucleic acid encapsulation to that of the origin of gene organization, expression, and regulation. In this work we discuss some reasons why preliminary steps in this direction are being taken. We have been led to examine properties that have contributed to raise the ancestral prokaryotic programmes to a level where we can appreciate in eukaryotes a clear departure from earlier themes in the evolution of cell from the last common ancestor. We shift our point of view from evolution of cell morphology to the point of view of the genes. In particular we focus attention on possible physical bases for the way transmission of information has evolved in eukaryotes, namely, the inactivation of whole chromosomes. The special case of the inactivation of the X chromosome in mammals is discussed, paying particular attention to the physical process of the spread of X inactivation in monotremes (platypus and echidna). When experimental data is unavailable some theoretical analysis is possible based on the idea that in certain cases collective phenomena in genetics, rather than chemical detail, are better correlates of complex chemical processes. (author). 65 refs

  4. Convergent evolution of a complex fruit structure in the tribe Brassiceae (Brassicaceae).

    Science.gov (United States)

    Hall, Jocelyn C; Tisdale, Tracy E; Donohue, Kathleen; Wheeler, Andrew; Al-Yahya, Mohammed A; Kramer, Elena M

    2011-12-01

    Many angiosperms have fruit morphologies that result in seeds from the same plant having different dispersal capabilities. A prime example is found in the Brassiceae (Brassicaceae), which has many members with segmented or heteroarthrocarpic fruits. Since only 40% of the genera are heteroarthrocarpic, this tribe provides an opportunity to study the evolution of an ecologically significant novelty and its variants. We analyzed nuclear (PHYA) and plastid (matK) sequences from 66 accessions using maximum parsimony, maximum likelihood, and Bayesian inference approaches. The evolution of heteroarthrocarpy and its variants was evaluated using maximum parsimony and maximum likelihood ancestral state reconstructions. Although nuclear and plastid phylogenies are incongruent with each other, the following findings are consistent: (1) Cakile, Crambe, Vella, and Zilla lineages are monophyletic; (2) the Nigra lineage is not monophyletic; and (3) within the Cakile clade, Cakile, Didesmus, and Erucaria are paraphyletic. Despite differences in the matK and PHYA topologies at both deep and shallow nodes, similar patterns of morphological evolution emerge. Heteroarthrocarpy, a complex morphological trait, has evolved multiple times across the tribe. Moreover, there are convergent transitions in dehiscence capabilities and fruit disarticulation across the tribe. We present the first explicit analysis of fruit evolution within the Brassiceae, which exemplifies evolutionary lability. The repeated loss and gain of segment dehiscence and disarticulation suggests conservation in the genetic pathway controlling abscission with differential expression across taxa. This study provides a strong foundation for future studies of mechanisms underlying variation in dispersal capabilities of Brassiceae.

  5. Phase field modeling of grain structure evolution during directional solidification of multi-crystalline silicon sheet

    Science.gov (United States)

    Lin, H. K.; Lan, C. W.

    2017-10-01

    Evolution of grain structures and grain boundaries (GBs), especially the coincident site lattice GBs, during directional solidification of multi-crystalline silicon sheet are simulated by using a phase field model for the first time. Since the coincident site lattice GBs having lower mobility, tend to follow their own crystallographic directions despite thermal gradients, the anisotropic energy and mobility of GBs are considered in the model. Three basic interactions of GBs during solidification are examined and they are consistent with experiments. The twinning process for new grain formation is further added in the simulation by considering twin nucleation. The effect of initial distribution of GB types and grain orientations is also investigated for the twinning frequency and the evolution of grain size and GB types.

  6. Decoupling of the Leading Order DGLAP Evolution Equation with Spin Dependent Structure Functions

    Science.gov (United States)

    Azadbakht, F. Teimoury; Boroun, G. R.

    2018-02-01

    We propose an analytical solution for DGLAP evolution equations with polarized splitting functions at the Leading Order (LO) approximation based on the Laplace transform method. It is shown that the DGLAP evolution equations can be decoupled completely into two second order differential equations which then are solved analytically by using the initial conditions δ FS(x,Q2)=F[partial δ FS0(x), δ FS0(x)] and {δ G}(x,Q2)=G[partial δ G0(x), δ G0(x)]. We used this method to obtain the polarized structure function of the proton as well as the polarized gluon distribution function inside the proton and compared the numerical results with experimental data of COMPASS, HERMES, and AAC'08 Collaborations. It was found that there is a good agreement between our predictions and the experiments.

  7. The impact of nonlinear functional responses on the long-term evolution of food web structure.

    Science.gov (United States)

    Drossel, Barbara; McKane, Alan J; Quince, Christopher

    2004-08-21

    We investigate the long-term web structure emerging in evolutionary food web models when different types of functional responses are used. We find that large and complex webs with several trophic layers arise only if the population dynamics is such that it allows predators to focus on their best prey species. This can be achieved using modified Lotka-Volterra or Holling/Beddington functional responses with effective couplings that depend on the predator's efficiency at exploiting the prey, or a ratio-dependent functional response with adaptive foraging. In contrast, if standard Lotka-Volterra or Holling/Beddington functional responses are used, long-term evolution generates webs with almost all species being basal, and with additionally many links between these species. Interestingly, in all cases studied, a large proportion of weak links result naturally from the evolution of the food webs.

  8. Pollen sensitivity to ultraviolet-B (UV-B) suggests floral structure evolution in alpine plants.

    Science.gov (United States)

    Zhang, Chan; Yang, Yong-Ping; Duan, Yuan-Wen

    2014-03-31

    Various biotic and abiotic factors are known to exert selection pressures on floral traits, but the influence of ultraviolet-B (UV-B) light on the evolution of flower structure remains relatively unexplored. We have examined the effectiveness of flower structure in blocking radiation and the effects of UV-B on pollen viability in 42 species of alpine plants in the Hengduan Mountains, China. Floral forms were categorized as either protecting or exposing pollen grains to UV-B. The floral materials of plants with exposed and protected pollen grains were able to block UV-B at similar levels. Exposure to UV-B radiation in vitro resulted in a significantly greater loss of viability in pollen from plant species with protective floral structures. The pronounced sensitivity of protected pollen to UV-B radiation was associated with the type of flower structure. These findings demonstrate that UV-B plays an important role in the evolution of protective floral forms in alpine plants.

  9. Using rhetorical structure in sentiment analysis

    NARCIS (Netherlands)

    Hogenboom, Alexander; Frasincar, Flavius; de Jong, Franciska M.G.; Kaymak, Uzay

    Automated sentiment analysis has become an active field of study with a broad applicability. One of the key open research issues lies in dealing with structural aspects of text when analyzing its conveyed sentiment. Recent work uses structural aspects of text in order to distinguish important text

  10. Synthesis, crystal structure, thermal analysis and dielectric ...

    Indian Academy of Sciences (India)

    In both the materials, the crystal structure has been determined by X-ray single crystal analysis at room temperature (293 K). The compound structures consist of K + (or NH 4 + ) cations and double chains of CdCl 6 octahedra sharing one edge extending along b -axis. The mixture of KA + /NH 4 + cations are located ...

  11. Fourier Analysis Of Vibrations Of Round Structures

    Science.gov (United States)

    Davis, Gary A.

    1990-01-01

    Fourier-series representation developed for analysis of vibrations in complicated, round structures like turbopump impellers. Method eliminates guesswork involved in characterization of shapes of vibrational modes. Easy way to characterize complicated modes, leading to determination of responsiveness of given mode to various forcing functions. Used in conjunction with finite-element numerical simulation of vibrational modes of structure.

  12. Rhetorical Structure Theory and Text Analysis

    Science.gov (United States)

    1989-11-01

    NO. NO. ACCESSION NO. 11. TITLE (include Security Clasification ) Rhetorical Structure Theory and Text Analysis (Unclassified) 12. PERSONAL AUTHOR(S...34Antithesis: A Study in Clause Combining and Discourse Structure ," in Ross Steele and Terry Threadgold (eds.), Language Topics: Essays in Honour of M

  13. Crystallographic Analysis and Structural Revision of a ...

    African Journals Online (AJOL)

    ABSTRACT. Single crystal X-ray analysis of a spiroterpenoid rearrangement product has revealed that its structure is, in fact, isomeric with the structure proposed previously – an observation that has significant mechanistic implications. KEYWORDS. Spiroterpenoid, rearrangement, X-ray crystallography, camphor derivative.

  14. Crystallographic Analysis and Structural Revision of a ...

    African Journals Online (AJOL)

    Single crystal X-ray analysis of a spiroterpenoid rearrangement product has revealed that its structure is, in fact, isomeric with the structure proposed previously – an observation that has significant mechanistic implications. Keywords: Spiroterpenoid, rearrangement, X-ray crystallography, camphor derivative.

  15. Covariance Structure Analysis: Seduced by Sophistication?

    Science.gov (United States)

    Wampold, Bruce E.

    1987-01-01

    Comments on Kerwin et al.'s article on covariance structure analysis (LISREL). Cautions that much effort must be made in developing the theory that describes the relationships among constructs and in establishing the measurement of these constructs before covariance structure is used. (ABB)

  16. Analysis of convergence for control problems governed by evolution ...

    African Journals Online (AJOL)

    The convergence of a scheme to minimize a class of a system of continuous optimal control problems characterized by a system of evolution equations and a system of linear inequality and equality constraints with multiplier imbedding is considered. The result is applied to some problems and the scheme is found to exhibit ...

  17. An Initial Quality Analysis of the Ohloh Software Evolution Data

    NARCIS (Netherlands)

    Bruntink, M.

    2014-01-01

    Large public data sets on software evolution promise great value to both researchers and practitioners, in particular for software (development) analytics. To realise this value, the data quality of such data sets needs to be studied and improved. Despite these data sets being of a secondary nature,

  18. Multidimensional analysis of Drosophila wing variation in Evolution ...

    Indian Academy of Sciences (India)

    2008-12-23

    Dec 23, 2008 ... has attracted much attention because of its importance as an ecological feature and the relative ease with which it can be exper- imentally manipulated in the lab. Evolution Canyon, Lower Nahal Oren, Israel, is a well studied natural site where ecological ...... in the skull of the house mouse. Proc. Roy. Soc.

  19. Computational structural analysis and finite element methods

    CERN Document Server

    Kaveh, A

    2014-01-01

    Graph theory gained initial prominence in science and engineering through its strong links with matrix algebra and computer science. Moreover, the structure of the mathematics is well suited to that of engineering problems in analysis and design. The methods of analysis in this book employ matrix algebra, graph theory and meta-heuristic algorithms, which are ideally suited for modern computational mechanics. Efficient methods are presented that lead to highly sparse and banded structural matrices. The main features of the book include: application of graph theory for efficient analysis; extension of the force method to finite element analysis; application of meta-heuristic algorithms to ordering and decomposition (sparse matrix technology); efficient use of symmetry and regularity in the force method; and simultaneous analysis and design of structures.

  20. Geostatistical investigation into the temporal evolution of spatial structure in a shallow water table

    Directory of Open Access Journals (Sweden)

    S. W. Lyon

    2006-01-01

    during many rain events. During the summer, when evaporation exceeds precipitation, the ranges of the indicator semivariograms decreased during rainfall events due to isolated responses in the water table. For the longer, monthly time interval, semivariograms exhibited higher sills and shorter ranges during spring and lower sills and longer ranges during the summer. For this long time interval, there was a good correlation between probability of exceeding the time-variable median water table and the soil topographical wetness index during the spring. Indicator kriging incorporating both the short and long time interval structure of the shallow water table (hard and soft data, respectively provided more realistic maps that agreed better with actual observations than the hard data alone. This technique to represent both event-based and seasonal trends incorporates the hillslope-scale hydrological processes to capture significant patterns in the shallow water table. Geostatistical analysis of the spatial and temporal evolution of the shallow water table gives information about the formation of saturated areas important in the understanding hydrological processes working at this and other hillslopes.

  1. Topological representation of the porous structure and its evolution of reservoir sandstone under excavation-induced loads

    Directory of Open Access Journals (Sweden)

    Ju Yang

    2017-01-01

    Full Text Available The porous structure of a reservoir rock greatly influences its evolutive deformation and fracture behavior during excavation of natural resources reservoirs. Most numerical models for porous structures have been used to predict the quasi-static mechanical properties, but few are available to accurately characterize the evolution process of the porous structure and its influence on the macroscopic properties of reservoir rocks. This study reports a novel method to characterize the porous structure of sandstone using its topological parameters and to determine the laws that govern the evolutive deformation and failure of the topological structure under various uniaxial compressive loads. A numerical model of the porous sandstone was established based on the pore characteristics that were acquired using computed tomography imaging techniques. The analytical method that integrates the grassfire algorithm and the maximum inscribed sphere algorithm was proposed to create the 3-D topological model of the deformed porous structure, through which the topological parameters of the structure were measured and identified. The evolution processes of the porous structure under various loads were characterized using its equivalent topological model and parameters. This study opens a new way to characterize the dynamic evolution of the pore structure of reservoir sandstone under excavation disturbance.

  2. Morphotectonic analysis, structural evolution/pattern of a ...

    Indian Academy of Sciences (India)

    young and rapid uplift (Pirazzoli et al. 1982 .... features; and (c): morphological features of the study area produced from 4 m digital elevation data. platform ... present. 3. Methodology. 3.1 Geographic Information System (GIS). Digitization techniques and GIS were applied for mapping representation of the data. The digital ...

  3. Structural Analysis in a Conceptual Design Framework

    Science.gov (United States)

    Padula, Sharon L.; Robinson, Jay H.; Eldred, Lloyd B.

    2012-01-01

    Supersonic aircraft designers must shape the outer mold line of the aircraft to improve multiple objectives, such as mission performance, cruise efficiency, and sonic-boom signatures. Conceptual designers have demonstrated an ability to assess these objectives for a large number of candidate designs. Other critical objectives and constraints, such as weight, fuel volume, aeroelastic effects, and structural soundness, are more difficult to address during the conceptual design process. The present research adds both static structural analysis and sizing to an existing conceptual design framework. The ultimate goal is to include structural analysis in the multidisciplinary optimization of a supersonic aircraft. Progress towards that goal is discussed and demonstrated.

  4. Image Analysis Technique for Material Behavior Evaluation in Civil Structures

    Science.gov (United States)

    Moretti, Michele; Rossi, Gianluca

    2017-01-01

    The article presents a hybrid monitoring technique for the measurement of the deformation field. The goal is to obtain information about crack propagation in existing structures, for the purpose of monitoring their state of health. The measurement technique is based on the capture and analysis of a digital image set. Special markers were used on the surface of the structures that can be removed without damaging existing structures as the historical masonry. The digital image analysis was done using software specifically designed in Matlab to follow the tracking of the markers and determine the evolution of the deformation state. The method can be used in any type of structure but is particularly suitable when it is necessary not to damage the surface of structures. A series of experiments carried out on masonry walls of the Oliverian Museum (Pesaro, Italy) and Palazzo Silvi (Perugia, Italy) have allowed the validation of the procedure elaborated by comparing the results with those derived from traditional measuring techniques. PMID:28773129

  5. Two-step relaxation mode analysis with multiple evolution times applied to all-atom molecular dynamics protein simulation

    Science.gov (United States)

    Karasawa, N.; Mitsutake, A.; Takano, H.

    2017-12-01

    Proteins implement their functionalities when folded into specific three-dimensional structures, and their functions are related to the protein structures and dynamics. Previously, we applied a relaxation mode analysis (RMA) method to protein systems; this method approximately estimates the slow relaxation modes and times via simulation and enables investigation of the dynamic properties underlying the protein structural fluctuations. Recently, two-step RMA with multiple evolution times has been proposed and applied to a slightly complex homopolymer system, i.e., a single [n ] polycatenane. This method can be applied to more complex heteropolymer systems, i.e., protein systems, to estimate the relaxation modes and times more accurately. In two-step RMA, we first perform RMA and obtain rough estimates of the relaxation modes and times. Then, we apply RMA with multiple evolution times to a small number of the slowest relaxation modes obtained in the previous calculation. Herein, we apply this method to the results of principal component analysis (PCA). First, PCA is applied to a 2-μ s molecular dynamics simulation of hen egg-white lysozyme in aqueous solution. Then, the two-step RMA method with multiple evolution times is applied to the obtained principal components. The slow relaxation modes and corresponding relaxation times for the principal components are much improved by the second RMA.

  6. Genome Evolution and Phylogenomic Analysis of Candidatus Kinetoplastibacterium, the Betaproteobacterial Endosymbionts of Strigomonas and Angomonas

    Science.gov (United States)

    Alves, João M.P.; Serrano, Myrna G.; Maia da Silva, Flávia; Voegtly, Logan J.; Matveyev, Andrey V.; Teixeira, Marta M.G.; Camargo, Erney P.; Buck, Gregory A.

    2013-01-01

    It has been long known that insect-infecting trypanosomatid flagellates from the genera Angomonas and Strigomonas harbor bacterial endosymbionts (Candidatus Kinetoplastibacterium or TPE [trypanosomatid proteobacterial endosymbiont]) that supplement the host metabolism. Based on previous analyses of other bacterial endosymbiont genomes from other lineages, a stereotypical path of genome evolution in such bacteria over the duration of their association with the eukaryotic host has been characterized. In this work, we sequence and analyze the genomes of five TPEs, perform their metabolic reconstruction, do an extensive phylogenomic analyses with all available Betaproteobacteria, and compare the TPEs with their nearest betaproteobacterial relatives. We also identify a number of housekeeping and central metabolism genes that seem to have undergone positive selection. Our genome structure analyses show total synteny among the five TPEs despite millions of years of divergence, and that this lineage follows the common path of genome evolution observed in other endosymbionts of diverse ancestries. As previously suggested by cell biology and biochemistry experiments, Ca. Kinetoplastibacterium spp. preferentially maintain those genes necessary for the biosynthesis of compounds needed by their hosts. We have also shown that metabolic and informational genes related to the cooperation with the host are overrepresented amongst genes shown to be under positive selection. Finally, our phylogenomic analysis shows that, while being in the Alcaligenaceae family of Betaproteobacteria, the closest relatives of these endosymbionts are not in the genus Bordetella as previously reported, but more likely in the Taylorella genus. PMID:23345457

  7. Ultra-deep sequencing reveals the subclonal structure and genomic evolution of oral squamous cell carcinoma

    DEFF Research Database (Denmark)

    Tabatabaeifar, Siavosh; Thomassen, Mads; Larsen, Martin Jakob

    Background: Oral squamous cell carcinoma (OSCC), a subgroup of head and neck squamous cell carcinoma (HNSCC), is primarily caused by alcohol consumption and tobacco use. Recent DNA sequencing studies suggests that HNSCC are very heterogeneous between patients; however the intra-patient subclonal...... structure remains unexplored due to lack of sampling multiple tumor biopsies from each patient. Materials and methods: To examine the clonal structure and describe the genomic cancer evolution we applied whole-exome sequencing combined with targeted ultra-deep targeted sequencing on biopsies from 5stage IV...... of unprecedented high resolution enabling clear detection of subclonal structure and observation of otherwise undetectable mutations. Furthermore, we demonstrate that OSCC show a high degree of inter-patient heterogeneity but a low degree of intra-patient/tumor heterogeneity. However, some OSCC cancers contain...

  8. Evolution of the IBDM Structural Latch Development into a Generic Simplified Design

    Science.gov (United States)

    DeVriendt, K.; Dittmer, H.; Vrancken, D.; Urmston, P.; Gracia, O.

    2010-01-01

    This paper presents the evolution in the development of the structural latch for the International Berthing Docking Mechanism (IBDM, see Figure 1). It reports on the lessons learned since completion of the test program on the engineering development unit of the first generation latching system in 2007. The initial latch design has been through a second generation concept in 2008, and now evolved into a third generation of this mechanism. Functional and structural testing on the latest latch hardware has recently been completed with good results. The IBDM latching system will provide the structural connection between two mated space vehicles after berthing or docking. The mechanism guarantees that the interface seals become compressed to form a leak-tight pressure system that creates a passageway for the astronauts.

  9. Nonlinear evolution of single spike structure and vortex in Richtmeyer-Meshkov instability

    International Nuclear Information System (INIS)

    Fukuda, Yuko O.; Nishihara, Katsunobu; Okamoto, Masayo; Nagatomo, Hideo; Matsuoka, Chihiro; Ishizaki, Ryuichi; Sakagami, Hitoshi

    1999-01-01

    Nonlinear evolution of single spike structure and vortex in the Richtmyer-Meshkov instability is investigated for two dimensional case, and axial symmetric and non axial symmetric cases with the use of a three-dimensional hydrodynamic code. It is shown that singularity appears in the vorticity left by transmitted and reflected shocks at a corrugated interface. This singularity results in opposite sign of vorticity along the interface that causes double spiral structure of the spike. Difference of nonlinear growth rate and double spiral structure among three cases is also discussed by visualization of simulation data. In a case that there is no slip-off of initial spike axis, vorticity ring is relatively stable, but phase rotation occurs. (author)

  10. Amorphous MoS2 nanosheets grown on copper@nickel-phosphorous dendritic structures for hydrogen evolution reaction

    Science.gov (United States)

    Ahn, Byung-Wook; Kim, Tae-Yoo; Kim, Seok-Hun; Song, Young-Il; Suh, Su-Jeong

    2018-02-01

    In this study, we introduce highly active, efficient, and Pt-free electrodes (Cu@Ni-P@a-MoS2) fabricated on Ni foils, which have good conductivity and several a-MoS2 edge sites for the hydrogen evolution reaction (HER). A porous Cu dendritic structure on Ni foil was made by electro-plating utilizing hydrogen bubbles, and a Ni-P film that covered the dendritic structure was made by electro-less plating. Vertically grown a-MoS2 nanosheets were formed on the Cu@Ni-P dendritic structure by thermolysis. The structure has abundant active sites because of its particular structure, which was examined by SEM and TEM. XPS analysis was used to confirm that MoS2 was reduced completely, and the a-MoS2 nanosheet layer was characterized by Raman spectroscopy. Electrochemical experiments demonstrated that the electrode was highly effective for the HER with a low onset potential of 118.5 mV, and a current density of 10 and 100 mA/cm2 for 186 and 345 mV versus the reversible hydrogen electrode potential (vs RHE), respectively, a small Tafel slope of 60.5 mV/dec, and was stable after 2000 cycles. This study demonstrates that highly porous Cu@Ni-P@a-MoS2 electrodes, possessing a huge surface, are desirable for the HER and these findings will pave the way for a new form of highly efficient electrocatalysts.

  11. Nonlinear structural analysis using integrated force method

    Indian Academy of Sciences (India)

    During the formulative period of structural analysis by matrix methods, earnest research was directed to automate the force ... (1973) for the analysis of discrete and continuous systems. IFM is a force method of .... (Nagabhushanam & Patnaik 1989) are being developed, which helps the use of efficient solution techniques for ...

  12. Impact analysis of composite aircraft structures

    Science.gov (United States)

    Pifko, Allan B.; Kushner, Alan S.

    1993-01-01

    The impact analysis of composite aircraft structures is discussed. Topics discussed include: background remarks on aircraft crashworthiness; comments on modeling strategies for crashworthiness simulation; initial study of simulation of progressive failure of an aircraft component constructed of composite material; and research direction in composite characterization for impact analysis.

  13. Structural Vibration Monitoring Using Cumulative Spectral Analysis

    Directory of Open Access Journals (Sweden)

    Satoru Goto

    2013-01-01

    Full Text Available This paper describes a resonance decay estimation for structural health monitoring in the presence of nonstationary vibrations. In structural health monitoring, the structure's frequency response and resonant decay characteristics are very important for understanding how the structure changes. Cumulative spectral analysis (CSA estimates the frequency decay by using the impulse response. However, measuring the impulse response of buildings is impractical due to the need to shake the building itself. In a previous study, we reported on system damping monitoring using cumulative harmonic analysis (CHA, which is based on CSA. The current study describes scale model experiments on estimating the hidden resonance decay under non-stationary noise conditions by using CSA for structural condition monitoring.

  14. Evolution of the magnetic structure with chemical composition in spinel iron oxide nanoparticles.

    Science.gov (United States)

    Muscas, G; Yaacoub, N; Concas, G; Sayed, F; Sayed Hassan, R; Greneche, J M; Cannas, C; Musinu, A; Foglietti, V; Casciardi, S; Sangregorio, C; Peddis, D

    2015-08-28

    Magnetic properties of iron oxide nanoparticles with spinel structure are strictly related to a complex interplay between cationic distribution and the presence of a non-collinear spin structure (spin canting). With the aim to gain better insight into the effect of the magnetic structure on magnetic properties, in this paper we investigated a family of small crystalline ferrite nanoparticles of the formula CoxNi1-xFe2O4 (0 ≤x≤ 1) having equal size (≈4.5 nm) and spherical-like shape. The field dependence of magnetization at low temperatures indicated a clear increase of magnetocrystalline anisotropy and saturation magnetization (higher than the bulk value for CoFe2O4: ∼130 A m(2) kg(-1)) with the increase of cobalt content. The magnetic structure of nanoparticles has been investigated by Mössbauer spectroscopy under an intense magnetic field (8 T) at a low temperature (10 K). The magnetic properties have been explained in terms of an evolution of the magnetic structure with the increase of cobalt content. In addition a direct correlation between cationic distribution and spin canting has been proposed, explaining the presence of a noncollinear spin structure in terms of superexchange interaction energy produced by the average cationic distribution and vacancies in the spinel structure.

  15. Effects of manganese doping on the structure evolution of small-sized boron clusters

    Science.gov (United States)

    Zhao, Lingquan; Qu, Xin; Wang, Yanchao; Lv, Jian; Zhang, Lijun; Hu, Ziyu; Gu, Guangrui; Ma, Yanming

    2017-07-01

    Atomic doping of clusters is known as an effective approach to stabilize or modify the structures and properties of resulting doped clusters. We herein report the effect of manganese (Mn) doping on the structure evolution of small-sized boron (B) clusters. The global minimum structures of both neutral and charged Mn doped B cluster \\text{MnB}nQ (n  =  10-20 and Q  =  0, ±1) have been proposed through extensive first-principles swarm-intelligence based structure searches. It is found that Mn doping has significantly modified the grow behaviors of B clusters, leading to two novel structural transitions from planar to tubular and then to cage-like B structures in both neutral and charged species. Half-sandwich-type structures are most favorable for small \\text{MnB}n-/0/+ (n  ⩽  13) clusters and gradually transform to Mn-centered double-ring tubular structures at \\text{MnB}16-/0/+ clusters with superior thermodynamic stabilities compared with their neighbors. Most strikingly, endohedral cages become the ground-state structures for larger \\text{MnB}n-/0/+ (n  ⩾  19) clusters, among which \\text{MnB}20+ adopts a highly symmetric structure with superior thermodynamic stability and a large HOMO-LUMO gap of 4.53 eV. The unique stability of the endohedral \\text{MnB}\\text{20}+ cage is attributed to the geometric fit and formation of 18-electron closed-shell configuration. The results significantly advance our understanding about the structure and bonding of B-based clusters and strongly suggest transition-metal doping as a viable route to synthesize intriguing B-based nanomaterials.

  16. Structural analysis of central and eastern Ovda Regio, Venus

    Science.gov (United States)

    Ghent, R. R.; Hansen, V. L.

    1997-03-01

    Ovda Regio is the largest of the Venusian crustal plateaus and lies in Western Aphrodite Terra, Venus. An understanding of the strain history of this region will provide a key to understanding the processes involved in the formation of Ovda Regio and of crustal plateaus in general. This paper reports on a detailed structural mapping and analysis of Ovda and implications for the tectonic evolution of Ovda and other crustal plateaus. The tectonic features of Ovda Regio were mapped using Magellan SAR images. The three major structures seen in Ovda Regio are folds, ribbons, and graben. The folds are interpreted to be contractional, and the graben and ribbons extensional. The strain history recorded in Ovda Regio involves early extension, followed by contraction, then later extension. This strain history is consistent with the formation of Ovda Regio by mantle upwelling.

  17. Evolution of self-organization in nano-structured PVD coatings under extreme tribological conditions

    Energy Technology Data Exchange (ETDEWEB)

    Fox-Rabinovich, G., E-mail: gfox@mcmaster.ca [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada); Kovalev, A. [Surface Phenomena Researches Group, CNIICHERMET, 9/23, 2-nd Baumanskaya Street, Moscow 105005 (Russian Federation); Aguirre, M.H. [Laboratory of Advanced Microscopy, Institute of Nanoscience of Aragón, University of Zaragoza, 50018 Zaragoza (Spain); Yamamoto, K. [Materials Research Laboratory, Kobe Steel Ltd, 1-5-5 Takatsuda-dai, Nishi-ku, Kobe 651-2271, Hyogo (Japan); Veldhuis, S. [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada); Gershman, I. [All-Russian Railway Research Institute, 10 Third Mytishchinskaya Street, Moscow 29851 (Russian Federation); Rashkovskiy, A. [Surface Phenomena Researches Group, CNIICHERMET, 9/23, 2-nd Baumanskaya Street, Moscow 105005 (Russian Federation); Endrino, J.L. [Albengoa Research, Energia Solar 1, Palmas Altas, Seville 41014 (Spain); Beake, B. [Micro Materials Limited, Willow House, Yale Business Village, Ellice Way, Wrexham LL13 7YL (United Kingdom); Dosbaeva, G. [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada); Wainstein, D. [Surface Phenomena Researches Group, CNIICHERMET, 9/23, 2-nd Baumanskaya Street, Moscow 105005 (Russian Federation); Yuan, Junifeng; Bunting, J.W. [Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4L7 (Canada)

    2014-04-01

    Highlights: • The evolution of self-organization under extreme frictional conditions has been studied. • Comprehensive characterization of the tribo-films was made using various surface analytical techniques. • During the running-in stage, mullite tribo-ceramics predominate on the surface of the nano-multilayer coating, establishing a functional hierarchy within the layer of tribo-films. • It is possible to control tribo-film evolution during self-organization by means of an increase in structural complexity and the non-equilibrium state of the surface engineered layer. - Abstract: The evolution of the self-organization process where dissipative structures are formed under the extreme frictional conditions associated with high performance dry machining of hardened steels has been studied in detail. The emphasis was on the progressive studies of surface transformations within multilayer and monolayer TiAlCrSiYN-based PVD coatings during the running-in stage of wear when self-organization process occurs. The coating layer was characterized by high resolution electron energy-loss spectroscopy (HREELS). It is shown that the nano-multilayer coating possesses higher non-equilibrium structure in comparison to the monolayer. Comprehensive studies of the tribo-films (dissipative structures) formed on the friction surface were made using a number of advanced surface characterization techniques such as X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES). The data obtained for the tribo-films was combined with the detailed TEM studies of the structural and phase transformations within the underlying coating layer. This data was related to the micro-mechanical characteristics of the coating layer and its wear resistance. It was demonstrated that the evolution of the self-organization process is strongly controlled by the characteristics of the tribo-films formed at different stages of the wear process. Within running-in stage (after

  18. The molecular clock of neutral evolution can be accelerated or slowed by asymmetric spatial structure.

    Directory of Open Access Journals (Sweden)

    Benjamin Allen

    2015-02-01

    Full Text Available Over time, a population acquires neutral genetic substitutions as a consequence of random drift. A famous result in population genetics asserts that the rate, K, at which these substitutions accumulate in the population coincides with the mutation rate, u, at which they arise in individuals: K = u. This identity enables genetic sequence data to be used as a "molecular clock" to estimate the timing of evolutionary events. While the molecular clock is known to be perturbed by selection, it is thought that K = u holds very generally for neutral evolution. Here we show that asymmetric spatial population structure can alter the molecular clock rate for neutral mutations, leading to either Ku. Our results apply to a general class of haploid, asexually reproducing, spatially structured populations. Deviations from K = u occur because mutations arise unequally at different sites and have different probabilities of fixation depending on where they arise. If birth rates are uniform across sites, then K ≤ u. In general, K can take any value between 0 and Nu. Our model can be applied to a variety of population structures. In one example, we investigate the accumulation of genetic mutations in the small intestine. In another application, we analyze over 900 Twitter networks to study the effect of network topology on the fixation of neutral innovations in social evolution.

  19. Structural evolution of epitaxial SrCoOx films near topotactic phase transition

    Science.gov (United States)

    Jeen, Hyoungjeen; Lee, Ho Nyung

    2015-12-01

    Control of oxygen stoichiometry in complex oxides via topotactic phase transition is an interesting avenue to not only modifying the physical properties, but utilizing in many energy technologies, such as energy storage and catalysts. However, detailed structural evolution in the close proximity of the topotactic phase transition in multivalent oxides has not been much studied. In this work, we used strontium cobaltites (SrCoOx) epitaxially grown by pulsed laser epitaxy (PLE) as a model system to study the oxidation-driven evolution of the structure, electronic, and magnetic properties. We grew coherently strained SrCoO2.5 thin films and performed post-annealing at various temperatures for topotactic conversion into the perovskite phase (SrCoO3-δ). We clearly observed significant changes in electronic transport, magnetism, and microstructure near the critical temperature for the topotactic transformation from the brownmillerite to the perovskite phase. Nevertheless, the overall crystallinity was well maintained without much structural degradation, indicating that topotactic phase control can be a useful tool to control the physical properties repeatedly via redox reactions.

  20. Structural evolution of epitaxial SrCoOx films near topotactic phase transition

    Directory of Open Access Journals (Sweden)

    Hyoungjeen Jeen

    2015-12-01

    Full Text Available Control of oxygen stoichiometry in complex oxides via topotactic phase transition is an interesting avenue to not only modifying the physical properties, but utilizing in many energy technologies, such as energy storage and catalysts. However, detailed structural evolution in the close proximity of the topotactic phase transition in multivalent oxides has not been much studied. In this work, we used strontium cobaltites (SrCoOx epitaxially grown by pulsed laser epitaxy (PLE as a model system to study the oxidation-driven evolution of the structure, electronic, and magnetic properties. We grew coherently strained SrCoO2.5 thin films and performed post-annealing at various temperatures for topotactic conversion into the perovskite phase (SrCoO3-δ. We clearly observed significant changes in electronic transport, magnetism, and microstructure near the critical temperature for the topotactic transformation from the brownmillerite to the perovskite phase. Nevertheless, the overall crystallinity was well maintained without much structural degradation, indicating that topotactic phase control can be a useful tool to control the physical properties repeatedly via redox reactions.

  1. Structural evolution of epitaxial SrCoO{sub x} films near topotactic phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Jeen, Hyoungjeen [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Physics, Pusan National University, Busan, 609735 (Korea, Republic of); Lee, Ho Nyung, E-mail: hnlee@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-12-15

    Control of oxygen stoichiometry in complex oxides via topotactic phase transition is an interesting avenue to not only modifying the physical properties, but utilizing in many energy technologies, such as energy storage and catalysts. However, detailed structural evolution in the close proximity of the topotactic phase transition in multivalent oxides has not been much studied. In this work, we used strontium cobaltites (SrCoO{sub x}) epitaxially grown by pulsed laser epitaxy (PLE) as a model system to study the oxidation-driven evolution of the structure, electronic, and magnetic properties. We grew coherently strained SrCoO{sub 2.5} thin films and performed post-annealing at various temperatures for topotactic conversion into the perovskite phase (SrCoO{sub 3-δ}). We clearly observed significant changes in electronic transport, magnetism, and microstructure near the critical temperature for the topotactic transformation from the brownmillerite to the perovskite phase. Nevertheless, the overall crystallinity was well maintained without much structural degradation, indicating that topotactic phase control can be a useful tool to control the physical properties repeatedly via redox reactions.

  2. Structural evolutions of supported Co clusters with different configurations on the Cu(010) substrate

    Science.gov (United States)

    Li, Guojian; Sui, Xudong; Wu, Chun; Wang, Qiang; Wang, Kai; He, Jicheng

    2015-12-01

    Structural evolutions of Co561 clusters supported on the Cu(010) substrate were studied by molecular dynamics simulation using an embedded atom method. Energy, snapshot, pair distribution function and epitaxial factor were used to analyze the effects of supported position, configuration and temperature on the structural evolutions. It is found that the energy of the cluster changes significantly with varying the supported position and the original configuration. The most stable supported position is (111) facet. As a function of configuration the stability decreases in the order: icosahedron > truncated octahedron > decahedron > cuboctahedron > sphere. Supported (111) facet changes to stack along the (100) of substrate. Epitaxial growth on the substrate occurs for all configurations. The epitaxial temperature and the amount of epitaxial atoms are related to the configuration. The epitaxial growth is adverse to the stability of the cluster, while the epitaxy has no effect on the crystal structure of the supported cluster. The energy of the cluster is reduced by the epitaxial growth and atomic penetration into the substrate but is enhanced by the distortion of the cluster on the substrate.

  3. Correlating cycling history with structural evolution in commercial 26650 batteries using in operando neutron powder diffraction

    Science.gov (United States)

    Goonetilleke, Damian; Pramudita, James C.; Hagan, Mackenzie; Al Bahri, Othman K.; Pang, Wei Kong; Peterson, Vanessa K.; Groot, Jens; Berg, Helena; Sharma, Neeraj

    2017-03-01

    Ex situ and time-resolved in operando neutron powder diffraction (NPD) has been used to study the structural evolution of the graphite negative electrode and LiFePO4 positive electrode within ANR26650M1A commercial batteries from A123 Systems, in what to our knowledge is the first reported NPD study investigating a 26650-type battery. Batteries with different and accurately-known electrochemical and storage histories were studied, enabling the tell-tale signs of battery degradation to be elucidated using NPD. The ex-situ NPD data revealed that the intensity of the graphite/lithiated graphite (LixC6 or LiyC) reflections was affected by battery history, with lower lithiated graphite (LiC12) reflection intensities typically corresponding to more abused batteries. This indicates that the lithiation of graphite is less progressed in more abused batteries, and hence these batteries have lower capacities. In operando NPD allows the rate of structural evolution in the battery electrode materials to be correlated to the applied current. Interestingly, the electrodes exhibit different responses to the applied current that depend on the battery cycling history, with this particularly evident for the negative electrode. Therefore, this work illustrates how NPD can be used to correlate a battery history with electrode structure.

  4. Making Plants Break a Sweat: the Structure, Function, and Evolution of Plant Salt Glands.

    Science.gov (United States)

    Dassanayake, Maheshi; Larkin, John C

    2017-01-01

    Salt stress is a complex trait that poses a grand challenge in developing new crops better adapted to saline environments. Some plants, called recretohalophytes, that have naturally evolved to secrete excess salts through salt glands, offer an underexplored genetic resource for examining how plant development, anatomy, and physiology integrate to prevent excess salt from building up to toxic levels in plant tissue. In this review we examine the structure and evolution of salt glands, salt gland-specific gene expression, and the possibility that all salt glands have originated via evolutionary modifications of trichomes. Salt secretion via salt glands is found in more than 50 species in 14 angiosperm families distributed in caryophyllales, asterids, rosids, and grasses. The salt glands of these distantly related clades can be grouped into four structural classes. Although salt glands appear to have originated independently at least 12 times, they share convergently evolved features that facilitate salt compartmentalization and excretion. We review the structural diversity and evolution of salt glands, major transporters and proteins associated with salt transport and secretion in halophytes, salt gland relevant gene expression regulation, and the prospect for using new genomic and transcriptomic tools in combination with information from model organisms to better understand how salt glands contribute to salt tolerance. Finally, we consider the prospects for using this knowledge to engineer salt glands to increase salt tolerance in model species, and ultimately in crops.

  5. Computer-aided analyses of transport protein sequences: gleaning evidence concerning function, structure, biogenesis, and evolution.

    Science.gov (United States)

    Saier, M H

    1994-03-01

    Three-dimensional structures have been elucidated for very few integral membrane proteins. Computer methods can be used as guides for estimation of solute transport protein structure, function, biogenesis, and evolution. In this paper the application of currently available computer programs to over a dozen distinct families of transport proteins is reviewed. The reliability of sequence-based topological and localization analyses and the importance of sequence and residue conservation to structure and function are evaluated. Evidence concerning the nature and frequency of occurrence of domain shuffling, splicing, fusion, deletion, and duplication during evolution of specific transport protein families is also evaluated. Channel proteins are proposed to be functionally related to carriers. It is argued that energy coupling to transport was a late occurrence, superimposed on preexisting mechanisms of solute facilitation. It is shown that several transport protein families have evolved independently of each other, employing different routes, at different times in evolutionary history, to give topologically similar transmembrane protein complexes. The possible significance of this apparent topological convergence is discussed.

  6. Structural Evolution of the R-T Phase Boundary in KNN-Based Ceramics

    KAUST Repository

    Lv, Xiang

    2017-10-04

    Although a rhombohedral-tetragonal (R-T) phase boundary is known to substantially enhance the piezoelectric properties of potassium-sodium niobate ceramics, the structural evolution of the R-T phase boundary itself is still unclear. In this work, the structural evolution of R-T phase boundary from -150 °C to 200 °C is investigated in (0.99-x)K0.5Na0.5Nb1-ySbyO3-0.01CaSnO3-xBi0.5K0.5HfO3 (where x=0~0.05 with y=0.035, and y=0~0.07 with x=0.03) ceramics. Through temperature-dependent powder X-ray diffraction (XRD) patterns and Raman spectra, the structural evolution was determined to be Rhombohedral (R, <-125 °C) → Rhombohedral+Orthorhombic (R+O, -125 °C to 0 °C) → Rhombohedral+Tetragonal (R+T, 0 °C to 150 °C) → dominating Tetragonal (T, 200 °C to Curie temperature (TC)) → Cubic (C, >TC). In addition, the enhanced electrical properties (e.g., a direct piezoelectric coefficient (d33) of ~450±5 pC/N, a conversion piezoelectric coefficient (d33*) of ~580±5 pm/V, an electromechanical coupling factor (kp) of ~0.50±0.02, and TC~250 °C), fatigue-free behavior, and good thermal stability were exhibited by the ceramics possessing the R-T phase boundary. This work improves understanding of the physical mechanism behind the R-T phase boundary in KNN-based ceramics and is an important step towards their adoption in practical applications. This article is protected by copyright. All rights reserved.

  7. Numerical Limit Analysis of Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Larsen, Kasper Paaske

    For more than half a century, limit state analysis based on the extremum principles have been used to assess the load bearing capacity of reinforced concrete structures. Extensi- ve research within the field has lead to several techniques for performing such analysis manually. While these manual...... methods provide engineers with valuable tools for limit sta- te analysis, their application becomes difficult with increased structural complexity. The main challenge is to solve the optimization problem posed by the extremum principles. This thesis is a study of how numerical methods can be used to solve...... limit state analysis problems. The work focuses on determination of the load bearing capacity of reinforced concrete structures by employing the lower bound theorem and a finite element method using equilibrium elements is developed. The recent year’s development within the field of convex optimization...

  8. Analysis of the Paradigm Evolution of Digital Libraries in China

    Directory of Open Access Journals (Sweden)

    Tan Sun

    2007-10-01

    Full Text Available The authors analyze the developmental framework of digital libraries in China and point out their current demand characteristics, development requirements, and developmental period. They then conclude that it is necessary to start up a new paradigm evolution of a digital library, from a traditional digital library to a virtual digital library. On that basis, they describe in detail several problems and developmental approaches that developing a virtual digital library must deal with, drawing lessons from the prototype DILIGENT.

  9. Nation-Wide Mobile Network Energy Evolution Analysis

    DEFF Research Database (Denmark)

    Perez, Eva; Frank, Philipp; Micallef, Gilbert

    2013-01-01

    be supported. In most cases, these upgrades increase the energy consumption of the network even further. This paper presents a nation-wide case study, based on a commercial network of a leading European operator, intended to provide a clear understanding of how the energy consumption of mobile networks...... is expected to evolve from 2012 until 2020. The study also considers an efficient network capacity evolution path, including base station equipment improvement forecasts....

  10. The evolution of cuckoo parasitism: a comparative analysis.

    Science.gov (United States)

    Krüger, O; Davies, N B

    2002-02-22

    Cuckoos (family Cuculidae) show the highest diversity of breeding strategies within one bird family (parental care, facultative and obligate brood parasites). We used independent contrasts from two phylogenies to examine how this variation was related to 13 ecological and life-history variables. The ancestral state was probably tropical, resident, forest cuckoos with parental care. The evolution of brood parasitism was correlated with a shift to more open habitats, a change in diet, increases in species breeding-range size and migration, and a decrease in egg size. Once parasitism had evolved, more elaborate parasitic strategies (more harmful to host fitness) were correlated with decreased egg size, a change in diet, increased breeding-range size and migration, a shortened breeding season and a decrease in local abundance. Establishing the most probable evolutionary pathways, using the method of Pagel, shows that changes in ecological variables (such as migration, range size and diet type) preceded the evolution of brood parasitism, which is likely to be a later adaptation to reduce the cost of reproduction. By contrast, brood parasitism evolved before changes in egg size occurred, indicating that egg size is an adaptive trait in host--parasite coevolution. Our results suggest that the evolution of cuckoo brood parasitism reflects selection from both ecological pressures and host defences.

  11. Evolution of the fine-structure constant in runaway dilaton models

    Directory of Open Access Journals (Sweden)

    C.J.A.P. Martins

    2015-04-01

    Full Text Available We study the detailed evolution of the fine-structure constant α in the string-inspired runaway dilaton class of models of Damour, Piazza and Veneziano. We provide constraints on this scenario using the most recent α measurements and discuss ways to distinguish it from alternative models for varying α. For model parameters which saturate bounds from current observations, the redshift drift signal can differ considerably from that of the canonical ΛCDM paradigm at high redshifts. Measurements of this signal by the forthcoming European Extremely Large Telescope (E-ELT, together with more sensitive α measurements, will thus dramatically constrain these scenarios.

  12. Evolution of the fine-structure constant in runaway dilaton models

    Energy Technology Data Exchange (ETDEWEB)

    Martins, C.J.A.P., E-mail: Carlos.Martins@astro.up.pt [Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Instituto de Astrofísica e Ciências do Espaço, CAUP, Rua das Estrelas, 4150-762 Porto (Portugal); Vielzeuf, P.E., E-mail: pvielzeuf@ifae.es [Institut de Física d' Altes Energies, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Barcelona) (Spain); Martinelli, M., E-mail: martinelli@thphys.uni-heidelberg.de [Institute for Theoretical Physics, University of Heidelberg, Philosophenweg 16, 69120, Heidelberg (Germany); Calabrese, E., E-mail: erminia.calabrese@astro.ox.ac.uk [Sub-department of Astrophysics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Pandolfi, S., E-mail: stefania@dark-cosmology.dk [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2015-04-09

    We study the detailed evolution of the fine-structure constant α in the string-inspired runaway dilaton class of models of Damour, Piazza and Veneziano. We provide constraints on this scenario using the most recent α measurements and discuss ways to distinguish it from alternative models for varying α. For model parameters which saturate bounds from current observations, the redshift drift signal can differ considerably from that of the canonical ΛCDM paradigm at high redshifts. Measurements of this signal by the forthcoming European Extremely Large Telescope (E-ELT), together with more sensitive α measurements, will thus dramatically constrain these scenarios.

  13. Evolution of a Pathogen: A Comparative Genomics Analysis Identifies a Genetic Pathway to Pathogenesis in Acinetobacter

    Science.gov (United States)

    Sahl, Jason W.; Gillece, John D.; Schupp, James M.; Waddell, Victor G.; Driebe, Elizabeth M.; Engelthaler, David M.; Keim, Paul

    2013-01-01

    Acinetobacter baumannii is an emergent and global nosocomial pathogen. In addition to A. baumannii, other Acinetobacter species, especially those in the Acinetobacter calcoaceticus-baumannii (Acb) complex, have also been associated with serious human infection. Although mechanisms of attachment, persistence on abiotic surfaces, and pathogenesis in A. baumannii have been identified, the genetic mechanisms that explain the emergence of A. baumannii as the most widespread and virulent Acinetobacter species are not fully understood. Recent whole genome sequencing has provided insight into the phylogenetic structure of the genus Acinetobacter. However, a global comparison of genomic features between Acinetobacter spp. has not been described in the literature. In this study, 136 Acinetobacter genomes, including 67 sequenced in this study, were compared to identify the acquisition and loss of genes in the expansion of the Acinetobacter genus. A whole genome phylogeny confirmed that A. baumannii is a monophyletic clade and that the larger Acb complex is also a well-supported monophyletic group. The whole genome phylogeny provided the framework for a global genomic comparison based on a blast score ratio (BSR) analysis. The BSR analysis demonstrated that specific genes have been both lost and acquired in the evolution of A. baumannii. In addition, several genes associated with A. baumannii pathogenesis were found to be more conserved in the Acb complex, and especially in A. baumannii, than in other Acinetobacter genomes; until recently, a global analysis of the distribution and conservation of virulence factors across the genus was not possible. The results demonstrate that the acquisition of specific virulence factors has likely contributed to the widespread persistence and virulence of A. baumannii. The identification of novel features associated with transcriptional regulation and acquired by clades in the Acb complex presents targets for better understanding the

  14. Evolution of a pathogen: a comparative genomics analysis identifies a genetic pathway to pathogenesis in Acinetobacter.

    Directory of Open Access Journals (Sweden)

    Jason W Sahl

    Full Text Available Acinetobacter baumannii is an emergent and global nosocomial pathogen. In addition to A. baumannii, other Acinetobacter species, especially those in the Acinetobacter calcoaceticus-baumannii (Acb complex, have also been associated with serious human infection. Although mechanisms of attachment, persistence on abiotic surfaces, and pathogenesis in A. baumannii have been identified, the genetic mechanisms that explain the emergence of A. baumannii as the most widespread and virulent Acinetobacter species are not fully understood. Recent whole genome sequencing has provided insight into the phylogenetic structure of the genus Acinetobacter. However, a global comparison of genomic features between Acinetobacter spp. has not been described in the literature. In this study, 136 Acinetobacter genomes, including 67 sequenced in this study, were compared to identify the acquisition and loss of genes in the expansion of the Acinetobacter genus. A whole genome phylogeny confirmed that A. baumannii is a monophyletic clade and that the larger Acb complex is also a well-supported monophyletic group. The whole genome phylogeny provided the framework for a global genomic comparison based on a blast score ratio (BSR analysis. The BSR analysis demonstrated that specific genes have been both lost and acquired in the evolution of A. baumannii. In addition, several genes associated with A. baumannii pathogenesis were found to be more conserved in the Acb complex, and especially in A. baumannii, than in other Acinetobacter genomes; until recently, a global analysis of the distribution and conservation of virulence factors across the genus was not possible. The results demonstrate that the acquisition of specific virulence factors has likely contributed to the widespread persistence and virulence of A. baumannii. The identification of novel features associated with transcriptional regulation and acquired by clades in the Acb complex presents targets for better

  15. Plausible mechanisms for brain structural and size changes in human evolution.

    Science.gov (United States)

    Blazek, Vladimir; Brùzek, Jaroslav; Casanova, Manuel F

    2011-09-01

    Encephalization has many contexts and implications. On one hand, it is concerned with the transformation of eating habits, social relationships and communication, cognitive skills and the mind. Along with the increase in brain size on the other hand, encephalization is connected with the creation of more complex brain structures, namely in the cerebral cortex. It is imperative to inquire into the mechanisms which are linked with brain growth and to find out which of these mechanisms allow it and determine it. There exist a number of theories for understanding human brain evolution which originate from neurological sciences. These theories are the concept of radial units, minicolumns, mirror neurons, and neurocognitive networks. Over the course of evolution, it is evident that a whole range of changes have taken place in regards to heredity. These changes include new mutations of genes in the microcephalin complex, gene duplications, gene co-expression, and genomic imprinting. This complex study of the growth and reorganization of the brain and the functioning of hereditary factors and their external influences creates an opportunity to consider the implications of cultural evolution and cognitive faculties.

  16. Analysis of latent structures in linear systems

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    2004-01-01

    In chemometrics the emphasis is on latent structure models. The latent structure is the part of the data that the modeling task is based upon. This paper is addressing some fundamental issues, when latent structures are used. The paper consists of three parts. The first part is concerned defining...... the latent structure of a linear model. Here the ‘atomic’ parts of the algorithms that generate the latent structure for linear models are analyzed. It is shown how the PLS algorithm fits within this way of presenting the numerical procedures. The second part is concerning graphic illustrations...... to use for deciding if single or multiple latent structures should be used. The last part is about choosing the variables that should be used in the analysis. The traditional procedures to select variables to include in the model are presented and the insufficiencies of such approaches are demonstrated...

  17. IMPACT OF GRAIN EVOLUTION ON THE CHEMICAL STRUCTURE OF PROTOPLANETARY DISKS

    International Nuclear Information System (INIS)

    Vasyunin, A. I.; Birnstiel, T.; Zhukovska, S.; Henning, T.; Dullemond, C. P.; Wiebe, D. S.

    2011-01-01

    We study the impact of dust evolution in a protoplanetary disk (PPD) around a T Tauri star on the disk's chemical composition. For the first time, we utilize a comprehensive model of dust evolution, which includes growth, fragmentation, and sedimentation. Specific attention is paid to the influence of grain evolution on the penetration of the UV field in the disk. A chemical model that includes a comprehensive set of gas-phase and grain-surface chemical reactions is used to simulate the chemical structure of the disk. The main effect of grain evolution on the disk's chemical composition comes from sedimentation and, to a lesser degree, from reduction of the total grain-surface area. The net effect of grain growth is suppressed by the fragmentation process which maintains a population of small grains, dominating the total grain surface area. We consider three models of dust properties. In model GS, both growth and sedimentation are taken into account. In models A5 and A4, all grains are assumed to be the same size (10 -5 cm and 10 -4 cm, respectively) with a constant gas-to-dust mass ratio of 100. As in previous studies, the 'three-layer' pattern (cold midplane, warm molecular layer, and hot atmosphere) in the disk-chemical structure is preserved in all models, but shifted closer to the midplane in models with increased grain size (GS and A4). Unlike other similar studies, we find that in models GS and A4, the column densities of most gas-phase species are enhanced by 1-3 orders of magnitude relative to those in a model with pristine dust (A5), while column densities of their surface counterparts are decreased. We show that column densities of certain species, such as C 2 H, HC 2n+1 N (n = 0-3), H 2 O, and some other molecules, as well as the C 2 H 2 /HCN abundance ratio, all of which are accessible with Herschel and ALMA, can be used as observational tracers of early stages of the grain evolution process in PPDs.

  18. Meta-analysis reveals evolution in invasive plant species but little support for Evolution of Increased Competitive Ability (EICA).

    Science.gov (United States)

    Felker-Quinn, Emmi; Schweitzer, Jennifer A; Bailey, Joseph K

    2013-03-01

    Ecological explanations for the success and persistence of invasive species vastly outnumber evolutionary hypotheses, yet evolution is a fundamental process in the success of any species. The Evolution of Increased Competitive Ability (EICA) hypothesis (Blossey and Nötzold 1995) proposes that evolutionary change in response to release from coevolved herbivores is responsible for the success of many invasive plant species. Studies that evaluate this hypothesis have used different approaches to test whether invasive populations allocate fewer resources to defense and more to growth and competitive ability than do source populations, with mixed results. We conducted a meta-analysis of experimental tests of evolutionary change in the context of EICA. In contrast to previous reviews, there was no support across invasive species for EICA's predictions regarding defense or competitive ability, although invasive populations were more productive than conspecific native populations under noncompetitive conditions. We found broad support for genetically based changes in defense and competitive plant traits after introduction into new ranges, but not in the manner suggested by EICA. This review suggests that evolution occurs as a result of plant introduction and population expansion in invasive plant species, and may contribute to the invasiveness and persistence of some introduced species.

  19. Intra-individual variation and evolution of modular structure in Draba plants.

    Science.gov (United States)

    Grigorieva, Olga V; Cherdantsev, Vladimir G

    2014-09-01

    We studied the evolution of quantitative traits related to shoot system architecture in a large genus Draba (Brassicaceae) making emphasis on the dynamics of relationship between individual and intra-individual variation. The results suggest that selection leading to origin of different life forms arises mainly from a necessity of moderation of the non-adaptive contest between the egoistic plant modules, taking care of self-reproduction of their own. We separated two evolutionary trends, one leading to the formation of short-lived monocarpic, and the other to long-lived polycarpic forms from the short-lived polycarpic plants. The first trend concerns with transformation of the innovation shoots into the axillary inflorescences by shortening of their vegetative developmental phase, while the second one - with individuation of the plant modules owing to acquisition of the capacity of rooting and separating from the mother plant. In both trends, the turning points of the evolution are those of originating of the negative for individual plants interactions between the plant modules being indirect non-adaptive consequences of the previous adaptive evolution and initiating selection for rebuilding of the plant modular structure. The difference between selection operating on intra-individual and individual variations is that, in the first case, combining of the characters of different individuals is infeasible. This leaves no choice for the evolution but to change the developmental mechanisms. In the case considered in this work, this is a change in shoot architecture using the material afforded by the natural variability of developmental pathways of the plant modules. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Artificial selection for structural color on butterfly wings and comparison with natural evolution.

    Science.gov (United States)

    Wasik, Bethany R; Liew, Seng Fatt; Lilien, David A; Dinwiddie, April J; Noh, Heeso; Cao, Hui; Monteiro, Antónia

    2014-08-19

    Brilliant animal colors often are produced from light interacting with intricate nano-morphologies present in biological materials such as butterfly wing scales. Surveys across widely divergent butterfly species have identified multiple mechanisms of structural color production; however, little is known about how these colors evolved. Here, we examine how closely related species and populations of Bicyclus butterflies have evolved violet structural color from brown-pigmented ancestors with UV structural color. We used artificial selection on a laboratory model butterfly, B. anynana, to evolve violet scales from UV brown scales and compared the mechanism of violet color production with that of two other Bicyclus species, Bicyclus sambulos and Bicyclus medontias, which have evolved violet/blue scales independently via natural selection. The UV reflectance peak of B. anynana brown scales shifted to violet over six generations of artificial selection (i.e., in less than 1 y) as the result of an increase in the thickness of the lower lamina in ground scales. Similar scale structures and the same mechanism for producing violet/blue structural colors were found in the other Bicyclus species. This work shows that populations harbor large amounts of standing genetic variation that can lead to rapid evolution of scales' structural color via slight modifications to the scales' physical dimensions.

  1. Electric field driven evolution of topological domain structure in hexagonal manganites

    Science.gov (United States)

    Yang, K. L.; Zhang, Y.; Zheng, S. H.; Lin, L.; Yan, Z. B.; Liu, J.-M.; Cheong, S.-W.

    2017-10-01

    Controlling and manipulating the topological state represents an important topic in condensed matters for both fundamental researches and applications. In this work, we focus on the evolution of a real-space topological domain structure in hexagonal manganites driven by electric field, using the analytical and numerical calculations based on the Ginzburg-Landau theory. It is revealed that the electric field drives a transition of the topological domain structure from the type-I pattern to the type-II one. In particular, it is identified that a high electric field can enforce the two antiphase-plus-ferroelectric (AP +FE ) domain walls with Δ Φ =π /3 to approach each other and to merge into one domain wall with Δ Φ = 2 π /3 eventually if the electric field is sufficiently high, where Δ Φ is the difference in the trimerization phase between two neighboring domains. Our simulations also reveal that the vortex cores of the topological structure can be disabled at a sufficiently high critical electric field by suppressing the structural trimerization therein, beyond which the vortex core region is replaced by a single ferroelectric domain without structural trimerization (Q = 0 ). Our results provide a stimulating reference for understanding the manipulation of real-space topological domain structure in hexagonal manganites.

  2. Diversity and evolution of floral structure among early diverging lineages in the Ericales.

    Science.gov (United States)

    Schönenberger, Jürg; von Balthazar, Maria; Sytsma, Kenneth J

    2010-02-12

    This is a combination of review and original data on floral structure and diversity in the two earliest diverging lineages of the Ericales, i.e. the balsaminoids, comprising Balsaminaceae, Marcgraviaceae and Tetrameristaceae, and the polemonioids, comprising Fouquieriaceae and Polemoniaceae. Each clade is strongly supported in molecular studies, while structural synapomorphies have largely been lacking. For the balsaminoid families, we compare floral morphology, anatomy and histology among selected taxa and find that the entire clade is strongly supported by the shared presence of nectariferous tissue in the floral periphery, thread-like structures on anthers, truncate stigmas, secretion in the ovary, as well as mucilage cells, raphides and tannins in floral tissues. A possible sister group relationship between Balsaminaceae and Tetrameristaceae is supported by the shared presence of post-genital fusion of filaments and ovary and a star-shaped stylar canal. For polemonioids, we document unexpected diversity of floral features in Polemoniaceae, partly providing structural links to Fouquieriaceae. Features include cochlear and quincuncial corolla aestivation, connective protrusions, ventrifixed anthers and nectariferous tissue in the base of the ovary. In addition, we outline future directions for research on floral structure in the Ericales and briefly discuss the general importance of structural studies for our understanding of plant phylogeny and evolution.

  3. Forest structure analysis combining laser scanning with digital airborne photogrammetry

    Science.gov (United States)

    Lissak, Candide; Onda, Yuichi; Kato, Hiroaki

    2017-04-01

    The interest of Light Detection and Ranging (LiDAR) for vegetation structure analysis has been demonstrated in several research context. Indeed, airborne or ground Lidar surveys can provide detailed three-dimensional data of the forest structure from understorey forest to the canopy. To characterize at different timescale the vegetation components in dense cedar forests we can combine several sources point clouds from Lidar survey and photogrammetry data. For our study, Terrestrial Laser Scanning (TLS-Leica ScanStation C10 processed with Cyclone software) have been lead in three forest areas (≈ 200m2 each zone) mainly composed of japanese cedar (Japonica cryptomeria), in the region of Fukushima (Japan). The study areas are characterized by various vegetation densities. For the 3 areas, Terrestrial laser scanning has been performed from several location points and several heights. Various floors shootings (ground, 4m, 6m and 18m high) were able with the use of a several meters high tower implanted to study the canopy evolution following the Fukushima Daiishi nuclear power plant accident. The combination of all scanners provides a very dense 3D point cloud of ground and canopy structure (average 300 000 000 points). For the Tochigi forest area, a first test of a low-cost Unmanned Aerial Vehicle (UAV) photogrammetry has been lead and calibrated by ground GPS measurements to determine the coordinates of points. TLS combined to UAV photogrammetry make it possible to obtain information on vertical and horizontal structure of the Tochigi forest. This combination of technologies will allow the forest structure mapping, morphometry analysis and the assessment of biomass volume evolution from multi-temporal point clouds. In our research, we used a low-cost UAV 3 Advanced (200 m2 cover, 1300 pictures...). Data processing were performed using PotoScan Pro software to obtain a very dense point clouds to combine to TLS data set. This low-cost UAV photogrammetry data has been

  4. The relationship of recombination rate, genome structure, and patterns of molecular evolution across angiosperms.

    Science.gov (United States)

    Tiley, George P; Burleigh, J Gordon; Burleigh, Gordon

    2015-09-16

    Although homologous recombination affects the efficacy of selection in populations, the pattern of recombination rate evolution and its effects on genome evolution across plants are largely unknown. Recombination can reduce genome size by enabling the removal of LTR retrotransposons, alter codon usage by GC biased gene conversion, contribute to complex histories of gene duplication and loss through tandem duplication, and enhance purifying selection on genes. Therefore, variation in recombination rate across species may explain some of the variation in genomic architecture as well as rates of molecular evolution. We used phylogenetic comparative methods to investigate the evolution of global meiotic recombination rate in angiosperms and its effects on genome architecture and selection at the molecular level using genetic maps and genome sequences from thirty angiosperm species. Recombination rate is negatively correlated with genome size, which is likely caused by the removal of LTR retrotransposons. After correcting recombination rates for euchromatin content, we also found an association between global recombination rate and average gene family size. This suggests a role for recombination in the preservation of duplicate genes or expansion of gene families. An analysis of the correlation between the ratio of nonsynonymous to synonymous substitution rates (dN/dS) and recombination rate in 3748 genes indicates that higher recombination rates are associated with an increased efficacy of purifying selection, suggesting that global recombination rates affect variation in rates of molecular evolution across distantly related angiosperm species, not just between populations. We also identified shifts in dN/dS for recombination proteins that are associated with shifts in global recombination rate across our sample of angiosperms. Although our analyses only reveal correlations, not mechanisms, and do not include potential covariates of recombination rate, like effective

  5. New Ulvan-Degrading Polysaccharide Lyase Family: Structure and Catalytic Mechanism Suggests Convergent Evolution of Active Site Architecture.

    Science.gov (United States)

    Ulaganathan, ThirumalaiSelvi; Boniecki, Michal T; Foran, Elizabeth; Buravenkov, Vitaliy; Mizrachi, Naama; Banin, Ehud; Helbert, William; Cygler, Miroslaw

    2017-05-19

    Ulvan is a complex sulfated polysaccharide biosynthesized by green seaweed and contains predominantly rhamnose, xylose, and uronic acid sugars. Ulvan-degrading enzymes have only recently been identified and added to the CAZy ( www.cazy.org ) database as family PL24, but neither their structure nor catalytic mechanism(s) are yet known. Several homologous, new ulvan lyases, have been discovered in Pseudoalteromonas sp. strain PLSV, Alteromonas LOR, and Nonlabens ulvanivorans, defining a new family PL25, with the lyase encoded by the gene PLSV_3936 being one of them. This enzyme cleaves the glycosidic bond between 3-sulfated rhamnose (R3S) and glucuronic acid (GlcA) or iduronic acid (IdoA) via a β-elimination mechanism. We report the crystal structure of PLSV_3936 and its complex with a tetrasaccharide substrate. PLSV_3936 folds into a seven-bladed β-propeller, with each blade consisting of four antiparallel β-strands. Sequence conservation analysis identified a highly conserved region lining at one end of a deep crevice on the protein surface. The putative active site was identified by mutagenesis and activity measurements. Crystal structure of the enzyme with a bound tetrasaccharide substrate confirmed the identity of base and acid residues and allowed determination of the catalytic mechanism and also the identification of residues neutralizing the uronic acid carboxylic group. The PLSV_3936 structure provides an example of a convergent evolution among polysaccharide lyases toward a common active site architecture embedded in distinct folds.

  6. The evolution of sheep production in Rio Grande do Sul and Uruguay: a comparative analysis of structural change Evolução da produção ovina no Rio Grande do Sul e Uruguai: análise comparativa de mudança estrutural

    Directory of Open Access Journals (Sweden)

    João Garibaldi Almeida Viana

    2013-06-01

    Full Text Available This study intended to analyze comparatively the evolution and the structural changes in sheep production in Rio Grande do Sul and Uruguay, being the international wool crisis used as a reference point. The analysis method was based on an econometrics time series, and the analysis began with the estimation of models that used linear and semi logarithmic regression. The estimation of the models proved that there were structural changes in sheep production in these regions, and this estimation used the wool crisis as a point of reference. In Rio Grande do Sul after 1990, the variables of sheep stock, wool and sheep meat presented a negative variable in their posted annual growth rates, as they decreased by 5.9%, 5.6% and 5.6%, respectively. The negative growth rates in Uruguay for the same variables in the same period were 6.1%, 5.6% and 0.9%, respectively. The data models indicate that there was no return to a balanced situation after the changes caused by the crisis. Therefore, the sheep market was permanently affected, which dynamically determined the evolution of sheep production and was defined by changes and uncertainty.O artigo teve por objetivo analisar comparativamente a evolução e a mudança estrutural da produção ovina no Rio Grande do Sul e Uruguai utilizando como ponto de referência a crise internacional de lã. O método de análise baseou-se na econometria de séries temporais, partindo da estimação de modelos de regressão linear e semilogarítmica. A estimação dos modelos comprovou a mudança estrutural na produção ovina do Rio Grande do Sul e Uruguai, tendo como referência a crise da lã. No Rio Grande do Sul, as variáveis de rebanho ovino, produção de lã e de carne ovina apresentou uma variação negativa em sua taxa anual pós-1990 de 5,9%, 5,6% e 5,6%, respectivamente. No Uruguai, as taxas negativas foram de 6,1%, 5,6% e 0,9%, para as mesmas variáveis do período. Os dados dos modelos indicam que não houve

  7. Analysis of particle species evolution in neutral beam injection lines

    International Nuclear Information System (INIS)

    Kim, J.; Haselton, H.H.

    1978-07-01

    Analytic solutions to the rate equations describing the species evolution of a multispecies positive ion beam of hydrogen due to charge exchange and molecular dissociation are derived as a function of the background gas (H 2 ) line density in the neutralizing gas cell and in the drift tube. Using the solutions, calculations are presented for the relative abundance of each species as a function of the gas cell thickness, the reionization loss rates in the drift tube, and the neutral beam power as a function of the beam energy and the species composition of the original ion beam

  8. Structural dynamic analysis of nuclear power plants

    International Nuclear Information System (INIS)

    Halbritter, A.L.; Koishi, N.; Prates, C.L.M.

    1986-01-01

    One of the most important items to be considered in order to guarantee the safety conditions of a Nuclear Power Plant is the design of the civil structures, the electrical and mechanical components and piping system taking into account non-conventional loading cases, e.g. earthquakes and explosions pressure waves. The general procedures used in the structural dynamic analysis of Nuclear Power Plants are presented, specially for seismic and explosion loads. (Author) [pt

  9. Large-scale trends in the evolution of gene structures within 11 animal genomes.

    Directory of Open Access Journals (Sweden)

    Mark Yandell

    2006-03-01

    Full Text Available We have used the annotations of six animal genomes (Homo sapiens, Mus musculus, Ciona intestinalis, Drosophila melanogaster, Anopheles gambiae, and Caenorhabditis elegans together with the sequences of five unannotated Drosophila genomes to survey changes in protein sequence and gene structure over a variety of timescales--from the less than 5 million years since the divergence of D. simulans and D. melanogaster to the more than 500 million years that have elapsed since the Cambrian explosion. To do so, we have developed a new open-source software library called CGL (for "Comparative Genomics Library". Our results demonstrate that change in intron-exon structure is gradual, clock-like, and largely independent of coding-sequence evolution. This means that genome annotations can be used in new ways to inform, corroborate, and test conclusions drawn from comparative genomics analyses that are based upon protein and nucleotide sequence similarities.

  10. Impact of long-term fertilization practice on soil structure evolution

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Møldrup, Per; Vogel, Hans-Jörg

    2014-01-01

    The study characterized soil structure development and evolution in six plots that were amended with varying amounts of animalmanure (AM) and NPK fertilizer over a period of 106 years in a long-termfertilization experiment in Bad Lauchstädt, Germany. Two intact soil cores (10-cm diameter and 8-cm......, and pore connectivity was significantly improved with increasing fertilizer amount. Furthermore, the soils fertilized with both AM and NPK showed a more aggregated structure than soils amended with AM only....... tall) and bulk soil samples were extracted froma depth between 5 and 15-cmfromeach plot. Soil properties including texture, organic carbon, soil–water characteristic, air permeability and diffusivity were measured and analyzed along with X-ray computed tomography (CT) data. Long...

  11. Aggregate size and structure determination of nanomaterials in physiological media: importance of dynamic evolution

    Science.gov (United States)

    Afrooz, A. R. M. Nabiul; Hussain, Saber M.; Saleh, Navid B.

    2014-12-01

    Most in vitro nanotoxicological assays are performed after 24 h exposure. However, in determining size and shape effect of nanoparticles in toxicity assays, initial characterization data are generally used to describe experimental outcome. The dynamic size and structure of aggregates are typically ignored in these studies. This brief communication reports dynamic evolution of aggregation characteristics of gold nanoparticles. The study finds that gradual increase in aggregate size of gold nanospheres (AuNS) occurs up to 6 h duration; beyond this time period, the aggregation process deviates from gradual to a more abrupt behavior as large networks are formed. Results of the study also show that aggregated clusters possess unique structural conformation depending on nominal diameter of the nanoparticles. The differences in fractal dimensions of the AuNS samples likely occurred due to geometric differences, causing larger packing propensities for smaller sized particles. Both such observations can have profound influence on dosimetry for in vitro nanotoxicity analyses.

  12. Structural evolution process of isotactic polypropylene in the isothermal crystallization from the melt

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, Kummetha Raghunatha; Tashiro, Kohji; Hanesaka, Makoto [Department of Future Industry-Oriented Basic Science and Materials, Graduate School of Engineering, Toyota Technological Institute, Tempaku, Nagoya 468-8511 (Japan); Sakurai, Takashi; Yamaguchi, Noburu [Petrochemical Research Laboratory, Sumitomo Chemical Co. Ltd., Chiba 299-0295 (Japan); Sasaki, Sono; Masunaga, Hiroyasu; Takata, Masaki, E-mail: ktashiro@toyota-ti.ac.j [Japan Synchrotron Radiation Research Institute (JASRI), Kouto, Sayo-gun, Hyogo, 679-5198 (Japan)

    2009-08-01

    The melt-isothermal crystallization behaviour has been investigated for isotactic polypropylene (iPP) by means of time-resolved simultaneous measurements of small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) using synchrotron radiation source in SPring-8. The time-resolved Fourier-transform infrared spectral (FTIR) measurements were also performed to clarify the formation process of helices. The SAXS data were analyzed on the basis of Guinier (isolated domains) and Debye-Bueche (correlated domains) theories and correlation function (stacked lamellae). The results were combined with the FTIR data, allowing us to draw the concrete structural evolution process including the formation of regular helices and their growth, the correlation of higher density domains consisting of these helices, and the increment of correlation between the neighbouring lamellae to build up the stacked lamellar structure of higher crystallinity.

  13. Ultra-deep sequencing reveals the subclonal structure and genomic evolution of oral squamous cell carcinoma

    DEFF Research Database (Denmark)

    Tabatabaeifar, Siavosh; Thomassen, Mads; Larsen, Martin Jakob

    Background: Oral squamous cell carcinoma (OSCC), a subgroup of head and neck squamous cell carcinoma (HNSCC), is primarily caused by alcohol consumption and tobacco use. Recent DNA sequencing studies suggests that HNSCC are very heterogeneous between patients; however the intra-patient subclonal...... structure remains unexplored due to lack of sampling multiple tumor biopsies from each patient. Materials and methods: To examine the clonal structure and describe the genomic cancer evolution we applied whole-exome sequencing combined with targeted ultra-deep targeted sequencing on biopsies from 5stage IV...... OSCC patients. From each patient, a series of biopsies were sampled from 3 distinct geographical sites in primary tumor and 1 lymph node metastasis. A whole blood sample was taken as the matched reference. Results and discussion: Our results demonstrate that ultra-deep sequencing gives a level...

  14. Evolution of Integrated Causal Structures in Animats Exposed to Environments of Increasing Complexity

    Science.gov (United States)

    Albantakis, Larissa; Hintze, Arend; Koch, Christof; Adami, Christoph; Tononi, Giulio

    2014-01-01

    Natural selection favors the evolution of brains that can capture fitness-relevant features of the environment's causal structure. We investigated the evolution of small, adaptive logic-gate networks (“animats”) in task environments where falling blocks of different sizes have to be caught or avoided in a ‘Tetris-like’ game. Solving these tasks requires the integration of sensor inputs and memory. Evolved networks were evaluated using measures of information integration, including the number of evolved concepts and the total amount of integrated conceptual information. The results show that, over the course of the animats' adaptation, i) the number of concepts grows; ii) integrated conceptual information increases; iii) this increase depends on the complexity of the environment, especially on the requirement for sequential memory. These results suggest that the need to capture the causal structure of a rich environment, given limited sensors and internal mechanisms, is an important driving force for organisms to develop highly integrated networks (“brains”) with many concepts, leading to an increase in their internal complexity. PMID:25521484

  15. Structural and magnetic properties evolution study method using a single ribbon-shaped sample

    Science.gov (United States)

    Moya, Javier A.

    2017-06-01

    A new type of study is presented for magnetic and structural characterization of amorphous or nanocrystalline metallic alloys in ribbon or wire-shaped samples. A single sample is subjecting to successive steps of flash isocurrent heat treatments with increasing duration in time, followed by a rapid cooling, while magneto-electric properties evolution are scanned in situ at room temperature. When one set of isocurrent heat treatments is finished, the annealing current is increased and a new set of isocurrent treatments starts. The properties studied were the saturation magnetization and the coercive field at 50 Hz, magnetic permeability at 100 kHz and electrical resistance from where we also obtained the crystalline fraction. The method was applied on two samples of Finemet-like alloys and the results were analyzed from the perspective of current literature. With the present method it is possible to obtain a general and meticulous understanding of the structural and magnetic evolution of the samples tested, with a considerable saving of time and samples.

  16. Structure evolution of Fe-50%Al coating prepared by mechanical alloying

    Science.gov (United States)

    Aryanto, D.; Wismogroho, A. S.; Sudiro, T.

    2016-08-01

    The deposition of Fe-50%Al coating (in at%) on low carbon steel was successfully prepared by using mechanical alloying (MA). The coating process was performed in a shaker mill with variation of milling times from 30 minute to 180 minutes. The deposited coating was then heat treated at 600°C for 2 hour in a vacuum furnace of 5.6 Pa. The structure evolution of mechanical alloyed samples before and after heat treatment was investigated by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDX) and X-ray diffractometer (XRD). The results revealed that before heat treatment, the deposited coating on low carbon steel is composed of Fe and Al. The Fe(Al) solid solution was mostly formed after 180 minutes of milling time. Metallographic observation indicated that the surface of Fe-Al coating was rough and the coating thickness was increased with increasing milling time. Meanwhile, the heat treatment process led to structural evolution by forming FeAl intermetallic phase on the surface of low carbon steel.

  17. Structure evolution of Fe-50%Al coating prepared by mechanical alloying

    International Nuclear Information System (INIS)

    Aryanto, D; Wismogroho, A S; Sudiro, T

    2016-01-01

    The deposition of Fe-50%Al coating (in at%) on low carbon steel was successfully prepared by using mechanical alloying (MA). The coating process was performed in a shaker mill with variation of milling times from 30 minute to 180 minutes. The deposited coating was then heat treated at 600°C for 2 hour in a vacuum furnace of 5.6 Pa. The structure evolution of mechanical alloyed samples before and after heat treatment was investigated by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDX) and X-ray diffractometer (XRD). The results revealed that before heat treatment, the deposited coating on low carbon steel is composed of Fe and Al. The Fe(Al) solid solution was mostly formed after 180 minutes of milling time. Metallographic observation indicated that the surface of Fe-Al coating was rough and the coating thickness was increased with increasing milling time. Meanwhile, the heat treatment process led to structural evolution by forming FeAl intermetallic phase on the surface of low carbon steel. (paper)

  18. Evolution of integrated causal structures in animats exposed to environments of increasing complexity.

    Directory of Open Access Journals (Sweden)

    Larissa Albantakis

    2014-12-01

    Full Text Available Natural selection favors the evolution of brains that can capture fitness-relevant features of the environment's causal structure. We investigated the evolution of small, adaptive logic-gate networks ("animats" in task environments where falling blocks of different sizes have to be caught or avoided in a 'Tetris-like' game. Solving these tasks requires the integration of sensor inputs and memory. Evolved networks were evaluated using measures of information integration, including the number of evolved concepts and the total amount of integrated conceptual information. The results show that, over the course of the animats' adaptation, i the number of concepts grows; ii integrated conceptual information increases; iii this increase depends on the complexity of the environment, especially on the requirement for sequential memory. These results suggest that the need to capture the causal structure of a rich environment, given limited sensors and internal mechanisms, is an important driving force for organisms to develop highly integrated networks ("brains" with many concepts, leading to an increase in their internal complexity.

  19. An effective continuum approach for modeling non-equilibrium structural evolution of protein nanofiber networks.

    Science.gov (United States)

    Cheng, Liang; Englander, Ongi; Paravastu, Anant; Oates, William S

    2011-08-07

    We quantify the formation and evolution of protein nanofibers using a new phase field modeling framework and compare the results to transmission electron microscopy measurements (TEM) and time-dependent growth measurements given in the literature. The modeling framework employs a set of effective continuum equations combined with underlying nanoscale forces and chemical potential relations governing protein nanofiber formation in solution. Calculations based on the theoretical framework are implemented numerically using a nonlinear finite element phase field modeling approach that couples homogenized protein molecular structure via a vector order parameter with chemical potential relations that describe interactions between the nanofibers and the surrounding solution. Homogenized, anisotropic molecular and chemical flux relations are found to be critical in obtaining nanofiber growth from seed particles or a random monomer bath. In addition, the model predicts both sigmoidal and first-order growth kinetics for protein nanofibers for unseeded and seeded models, respectively. These simulations include quantitative predictions on time scales of typical protein self-assembly behavior which qualitatively match TEM measurements of the RADA16-I protein and growth rate measurements for amyloid nanofibers from the literature. For comparisons with experiments, the numerical model performs multiple nanofiber protein evolution simulations with a characteristic length scale of ∼2.4 nm and characteristic time scale of ∼9.1 h. These results provide a new modeling tool that couples underlying monomer structure with self-assembling nanofiber behavior that is compatible with various external loadings and chemical environments.

  20. Comparative Analysis of the Macroscale Structural Connectivity in the Macaque and Human Brain

    NARCIS (Netherlands)

    Goulas, A.; Bastiani, M.; Bezgin, G.; Uylings, H.B.M.; Roebroeck, A.; Stiers, P.

    2014-01-01

    The macaque brain serves as a model for the human brain, but its suitability is challenged by unique human features, including connectivity reconfigurations, which emerged during primate evolution. We perform a quantitative comparative analysis of the whole brain macroscale structural connectivity

  1. THE INFLUENCE OF OUTER SOLAR SYSTEM ARCHITECTURE ON THE STRUCTURE AND EVOLUTION OF THE OORT CLOUD

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Alexia R.; Quinn, Thomas [Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States); Kaib, Nathan A., E-mail: arlewis@astro.washington.edu [Department of Physics and Astronomy and Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, Evanston, IL 60208-2900 (United States)

    2013-07-01

    We study the influence of outer solar system architecture on the structural evolution of the Oort Cloud (OC) and the flux of Earth-crossing comets. In particular, we seek to quantify the role of the giant planets as ''planetary protectors''. To do so, we have run simulations in each of four different planetary mass configurations to understand the significance of each of the giant planets. Because the outer planets modify the structure of the OC throughout its formation, we integrate each simulation over the full age of the solar system. Over this time, we follow the evolution of cometary orbits from their starting point in the protoplanetary disk to their injection into the OC to their possible re-entry into the inner planetary region. We find that the overall structure of the OC, including the location of boundaries and the relative number of comets in the inner and outer parts, does not change significantly between configurations; however, as planetary mass decreases, the trapping efficiency (TE) of comets into the OC and the flux of comets into the observable region increases. We determine that those comets that evolve onto Earth-crossing orbits come primarily from the inner OC but show no preference for initial protoplanetary disk location. We also find that systems that have at least a Saturn-mass object are effective at deflecting possible Earth-crossing comets but the difference in flux between systems with and without such a planet is less than an order of magnitude. We conclude by discussing the individual roles of the planets and the implications of incorporating more realistic planetary accretion and migration scenarios into simulations, particularly on existing discrepancies between low TE and the mass of the protoplanetary disk and on determining the structural boundaries of the OC.

  2. Data structures and algorithm analysis in Java

    CERN Document Server

    Shaffer, Clifford A

    2011-01-01

    With its focus on creating efficient data structures and algorithms, this comprehensive text helps readers understand how to select or design the tools that will best solve specific problems. It uses Java as the programming language and is suitable for second-year data structure courses and computer science courses in algorithm analysis. Techniques for representing data are presented within the context of assessing costs and benefits, promoting an understanding of the principles of algorithm analysis and the effects of a chosen physical medium. The text also explores tradeoff issues, familiari

  3. Data structures and algorithm analysis in C++

    CERN Document Server

    Shaffer, Clifford A

    2011-01-01

    With its focus on creating efficient data structures and algorithms, this comprehensive text helps readers understand how to select or design the tools that will best solve specific problems. It uses Microsoft C++ as the programming language and is suitable for second-year data structure courses and computer science courses in algorithm analysis.Techniques for representing data are presented within the context of assessing costs and benefits, promoting an understanding of the principles of algorithm analysis and the effects of a chosen physical medium. The text also explores tradeoff issues, f

  4. Ultrafast colorimetric determination of predominant protein structure evolution with gold nanoplasmonic particles

    Science.gov (United States)

    Kim, Hye Young; Choi, Inhee

    2016-01-01

    The intracellular and extracellular accumulation of disordered proteins and aggregated proteins occurs in many protein conformational diseases, such as aging-related neurodegeneration and alcoholic liver diseases. However, the conventional methods to study protein structural changes are limited for the rapid detection and monitoring of protein aggregation because of long incubation times (i.e., usually several days), complicated sample pretreatment steps, and expensive instrumentation. Here, we describe an ultrafast colorimetric method for the real-time monitoring of protein structure evolution and the determination of predominant structures via nanoparticle-assisted protein aggregation. During the aggregation process, nanoparticles act as nucleation cores, which form networks depending on the structures of the protein aggregates, and accelerate the kinetics of the protein aggregation. Simultaneously, these nanoparticles exhibit colorimetric responses according to their embedded shapes (e.g., fibrillar and amorphous) on the protein aggregates. We observed distinct spectral shifts and concomitant colorimetric responses of concentration- and type-dependent protein aggregation with the naked eye within a few minutes (drugs for protein conformational diseases.The intracellular and extracellular accumulation of disordered proteins and aggregated proteins occurs in many protein conformational diseases, such as aging-related neurodegeneration and alcoholic liver diseases. However, the conventional methods to study protein structural changes are limited for the rapid detection and monitoring of protein aggregation because of long incubation times (i.e., usually several days), complicated sample pretreatment steps, and expensive instrumentation. Here, we describe an ultrafast colorimetric method for the real-time monitoring of protein structure evolution and the determination of predominant structures via nanoparticle-assisted protein aggregation. During the aggregation

  5. MBS Analysis Of Kinetic Structures Using ADAMS

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R.K.

    2009-01-01

    The present paper considers multibody system (MBS) analysis of kinetic structures using the software package ADAMS. Deployable, foldable, expandable and reconfigurable kinetic structures can provide a change in the geometric morphology of the envelope by contributing to making it adaptable to e......-called multibody system (MBS) formalism. The present paper considers MBS modeling of kinetic architectural structures using the software packages ADAMS. As a result, it is found that symbolic MBS simulation tools facilitate a useful evaluation environment for MBS users during a design phase of responsive kinetic...

  6. Entity Authentication:Analysis using Structured Intuition

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.

    2010-01-01

    In this paper, we propose a new method for the analysis that uses intuition of the analyst in a structured way. First we define entity authentication in terms of fine level authentication goals (FLAGs). Then we use some relevant structures in protocol narrations and use them to justify FLAGs...... for the protocol. All along this process, we discover vulnerabilities and unstated assumptions of the protocol. As the method is intuition based, the quality of results depends on the expertise of the security analyst, however, the structured intuition has two major advantages: Firstly we get a precise...

  7. Reliability analysis of prestressed concrete containment structures

    International Nuclear Information System (INIS)

    Jiang, J.; Zhao, Y.; Sun, J.

    1993-01-01

    The reliability analysis of prestressed concrete containment structures subjected to combinations of static and dynamic loads with consideration of uncertainties of structural and load parameters is presented. Limit state probabilities for given parameters are calculated using the procedure developed at BNL, while that with consideration of parameter uncertainties are calculated by a fast integration for time variant structural reliability. The limit state surface of the prestressed concrete containment is constructed directly incorporating the prestress. The sensitivities of the Choleskey decomposition matrix and the natural vibration character are calculated by simplified procedures. (author)

  8. Application of Dynamic Mode Decomposition: Temporal Evolution of Flow Structures in an Aneurysm

    Science.gov (United States)

    Conlin, William; Yu, Paulo; Durgesh, Vibhav

    2017-11-01

    An aneurysm is an enlargement of a weakened arterial wall that can be fatal or debilitating on rupture. Aneurysm hemodynamics is integral to developing an understanding of aneurysm formation, growth, and rupture. The flow in an aneurysm exhibits complex fluid dynamics behavior due to an inherent unsteady inflow condition and its interactions with large-scale flow structures present in the aneurysm. The objective of this study is to identify the large-scale structures in the aneurysm, study temporal behavior, and quantify their interaction with the inflow condition. For this purpose, detailed Particle Image Velocimetry (PIV) measurements were performed at the center plane of an idealized aneurysm model for a range of inflow conditions. Inflow conditions were precisely controlled using a ViVitro SuperPump system. Dynamic Modal Decomposition (DMD) of the velocity field was used to identify coherent structures and their temporal behavior. DMD was successful in capturing the large-scale flow structures and their temporal behavior. A low dimensional approximation to the flow field was obtained with the most relevant dynamic modes and was used to obtain temporal information about the coherent structures and their interaction with the inflow, formation, evolution, and growth.

  9. Residential energy use in Mexico: Structure, evolution, environmental impacts, and savings potential

    Energy Technology Data Exchange (ETDEWEB)

    Masera, O.; Friedmann, R.; deBuen, O.

    1993-05-01

    This article examines the characteristics of residential energy use in Mexico, its environmental impacts, and the savings potential of the major end-uses. The main options and barriers to increase the efficiency of energy use are discussed. The energy analysis is based on a disaggregation of residential energy use by end-uses. The dynamics of the evolution of the residential energy sector during the past 20 years are also addressed when the information is available. Major areas for research and for innovative decision-making are identified and prioritized.

  10. Performance and Structural Evolution of Nano-Scale Infiltrated Solid Oxide Fuel Cell Cathodes

    Science.gov (United States)

    Call, Ann Virginia

    Nano-structured mixed ionic and electronic conducting (MIEC) materials have garnered intense interest in electrode development for solid oxide fuel cells due to their high surface areas which allow for effective catalytic activity and low polarization resistances. In particular, composite solid oxide fuel cell (SOFC) cathodes consisting of ionic conducting scaffolds infiltrated with MIEC nanoparticles have exhibited some of the lowest reported polarization resistances. In order for cells utilizing nanostructured moRPhologies to be viable for commercial implementation, more information on their initial performance and long term stability is necessary. In this study, symmetric cell cathodes were prepared via wet infiltration of Sr0.5Sm 0.5CoO3 (SSC) nano-particles via a nitrate process into porous Ce0.9Gd0.1O1.95 (GDC) scaffolds to be used as a model system to investigate performance and structural evolution. Detailed analysis of the cells and cathodes was carried out using electrochemical impedance spectroscopy (EIS). Initial polarization resistances (RP) as low as 0.11 O cm2 at 600ºC were obtained for these SSC-GDC cathodes, making them an ideal candidate for studying high performance nano-structured electrodes. The present results show that the infiltrated cathode microstructure has a direct impact on the initial performance of the cell. Small initial particle sizes and high infiltration loadings (up to 30 vol% SSC) improved initial RP. A simple microstructure-based electrochemical model successfully explained these trends in RP. Further understanding of electrode performance was gleaned from fitting EIS data gathered under varying temperatures and oxygen partial pressures to equivalent circuit models. Both RQ and Gerischer impedance elements provided good fits to the main response in the EIS data, which was associated with the combination of oxygen surface exchange and oxygen diffusion in the electrode. A gas diffusion response was also observed at relatively

  11. Nonlinear stability analysis of the frame structures

    Directory of Open Access Journals (Sweden)

    Ćorić Stanko

    2016-01-01

    Full Text Available In this paper the phenomenon of instability of frames in elasto-plastic domain was investigated. Numerical analysis was performed by the finite element method. Stiffness matrices were derived using the trigonometric shape functions related to exact solution of the differential equation of bending according to the second order theory. When the buckling of structure occurs in plastic domain, it is necessary to replace the constant modulus of elasticity E with the tangent modulus Et. Tangent modulus is stress dependent function and takes into account the changes of the member stiffness in the inelastic range. For the purposes of numerical investigation in this analysis, part of the computer program ALIN was created in a way that this program now can be used for elastic and elasto-plastic stability analysis of frame structures. This program is developed in the C++ programming language. Using this program, it is possible to calculate the critical load of frames in the elastic and inelastic domain. In this analysis, the algorithm for the calculation of buckling lengths of compressed columns of the frames was also established. The algorithm is based on the calculation of the global stability analysis of frame structures. Results obtained using this algorithm were compared with the approximate solutions from the European (EC3 and national (JUS standards for the steel structures. By the given procedure in this paper it is possible to follow the behavior of the plane frames in plastic domain and to calculate the real critical load in that domain.

  12. Object-Oriented Analysis, Structured Analysis, and Jackson System Development

    NARCIS (Netherlands)

    Van Assche, F.; Wieringa, Roelf J.; Moulin, B.; Rolland, C

    1991-01-01

    Conceptual modeling is the activity of producing a conceptual model of an actual or desired version of a universe of discourse (UoD). In this paper, two methods of conceptual modeling are compared, structured analysis (SA) and object-oriented analysis (OOA). This is done by transforming a model

  13. A physical map for the Amborella trichopoda genome sheds light on the evolution of angiosperm genome structure

    Science.gov (United States)

    2011-01-01

    Background Recent phylogenetic analyses have identified Amborella trichopoda, an understory tree species endemic to the forests of New Caledonia, as sister to a clade including all other known flowering plant species. The Amborella genome is a unique reference for understanding the evolution of angiosperm genomes because it can serve as an outgroup to root comparative analyses. A physical map, BAC end sequences and sample shotgun sequences provide a first view of the 870 Mbp Amborella genome. Results Analysis of Amborella BAC ends sequenced from each contig suggests that the density of long terminal repeat retrotransposons is negatively correlated with that of protein coding genes. Syntenic, presumably ancestral, gene blocks were identified in comparisons of the Amborella BAC contigs and the sequenced Arabidopsis thaliana, Populus trichocarpa, Vitis vinifera and Oryza sativa genomes. Parsimony mapping of the loss of synteny corroborates previous analyses suggesting that the rate of structural change has been more rapid on lineages leading to Arabidopsis and Oryza compared with lineages leading to Populus and Vitis. The gamma paleohexiploidy event identified in the Arabidopsis, Populus and Vitis genomes is shown to have occurred after the divergence of all other known angiosperms from the lineage leading to Amborella. Conclusions When placed in the context of a physical map, BAC end sequences representing just 5.4% of the Amborella genome have facilitated reconstruction of gene blocks that existed in the last common ancestor of all flowering plants. The Amborella genome is an invaluable reference for inferences concerning the ancestral angiosperm and subsequent genome evolution. PMID:21619600

  14. Parametric Study on the Evolution of Thermal Patterns and Coherent Flow Structures in the Rotated Arc Mixer

    Science.gov (United States)

    Baskan, Ozge; Speetjens, Michel; Metcalfe, Guy; Clercx, Herman

    2013-11-01

    Advective-diffusive scalar transport in spatially or temporally periodic flow fields has been investigated in numerous studies, which exposed that the global transport relies on the kinematic/geometric parameters governing the advection and the ratio between the advective and diffusive time scales. These studies mainly employ numerical/analytical methods. However, experimental analysis remains outstanding. This research concerns an experimental parametric study on the evolution of the thermal patterns in a representative configuration, the Rotated Arc Mixer (RAM), and its correlation with the coherent flow structures. The RAM is an inline mixer composed of a stationary inner cylinder with systematically oriented apertures and a rotating outer cylinder inducing transverse flow at the apertures. Design of the experimental facility is based on a 2D time-periodic simplification of the 3D spatially-periodic RAM, where the cross-sectional progression is represented by the temporal evolution. The test section is a shallow circular tank with apertures on the circumference and motor-driven belts imitate the rotating outer cylinder of the RAM. Circumferential temperature is kept constant via an enclosing hot-water reservoir. The 2D flow and temperature fields are measured by 2D Particle Image Velocimetry and Infrared Thermography and analyzed.

  15. Theoretical analysis of polarized structure functions

    International Nuclear Information System (INIS)

    Altarelli, G.; ); Ball, R.D.; Forte, S.; Ridolfi, G.

    1998-01-01

    We review the analysis of polarized structure function data using perturbative QCD and NLO We use the most recent experimental data to obtain updated results for polarized parton distributions, first moments and the strong coupling. We also discuss several theoretical issues involving in this analysis and in the interpretation of its results. Finally, we compare our results with other similar analyses in the recent literature. (author)

  16. Theoretical Analysis of Polarized Structure Functions

    CERN Document Server

    Altarelli, Guido; Forte, Stefano; Ridolfi, G

    1998-01-01

    We review the analysis of polarized structure function data using perturbative QCD at next-to-leading order. We use the most recent experimental data to obtain updated results for polarized parton distributions, first moments and the strong coupling. We also discuss several theoretical issues involved in this analysis and in the interpretation of its results. Finally, we compare our results with other similar analyses in the recent literature.

  17. Structural Analysis of Field Sprayer Booms

    OpenAIRE

    KOÇ, Caner

    2017-01-01

    In this paper, structural analysis of a 21 meters wide field sprayer boom, designed for precision agricultureapplications, was conducted with finite element analysis. G-programming language, a data acquisition board andan inductive force transducer were used to measure the forces acting on the boom arms. An experimental setup,developed in a laboratory environment, was able to measure and record various forces in 5 miliseconds intervals.An ANSYS model was developed to analyze the forces record...

  18. Structural evolution of Pico del Águila anticline (External Sierras, southern Pyrenees) derived from sandbox, numerical and 3D structural modelling techniques

    OpenAIRE

    VIDAL-ROYO, O.; MUÑOZ, J.A.; HARDY, S.; KOYI, H.; CARDOZO, N.

    2013-01-01

    This paper reports on the integration of different modelling techniques to construct a unified conceptual model of structural evolution of the Pico del Águila anticline (External Sierras, southern Pyrenees, Spain). The structure is a well-known example of a detachment fold, which exhibits a N-S structural trend, perpendicular to the general structural trend of the southern Pyrenees (mainly E-W). Based on field observations of an unevenly distributed Triassic décollement, analogue modelling sh...

  19. Nonlinearity and isotope effect in temporal evolution of mesoscopic structure during hydration of cement

    International Nuclear Information System (INIS)

    Mazumder, S.

    2011-01-01

    Investigations of cement is still in its infancy despite the fact that cement is ubiquitous material which is indispensable in the construction industry, in nuclear energy programs for immobilization of non heat-generating low-level radioactive waste, and in the petroleum industry to line oil wells by pumping cement slurry to isolate productive zones and with global production exceeding that of any other material of technological importance. The total world consumption of cement in 2008 was about 2.5 billion metric tons almost double of that of steel. Manufacturing of cement contributes about 4% of global and 5-7% of the total man-made CO 2 emissions. The understanding of the mechanism of its hydration and evolution of cement-water mixtures into a material of high compressive strength is paramount to improve its life time and other macroscopic properties such as compressive strength, permeability, elastic modulus etc. The mechanism of hydration of cement and evolution of cement-water mixtures into gels of high compressive strength is poorly understood, despite extensive research over the past century. Recent investigations, based on neutron scattering measurements, aims at unraveling this enigma and outlines, for the first time, the evolution of the mesoscopic structure of the cement paste which exhibits temporal oscillations, strongly dependent on the scale of observation and on the medium of hydration (light or heavy water). While the formation of hydration products is synchronous for hydration with H 2 O, the process is non-synchronous for hydration with D 2 O. The reason why morphological patterns of domains at different times look dissimilar, as seen before, for different hydration media emerges as a natural consequence of this finding. Mesoscopic structure of cement paste exhibits isotope effect. The structures arise from well- characterised chemical reactions as water diffuses through the porous material to bring about the water-surface interactions within

  20. Importance of initial buoyancy field on evolution of mantle thermal structure: Implications of surface boundary conditions

    Directory of Open Access Journals (Sweden)

    Petar Glišović

    2015-01-01

    Full Text Available Although there has been significant progress in the seismic imaging of mantle heterogeneity, the outstanding issue that remains to be resolved is the unknown distribution of mantle temperature anomalies in the distant geological past that give rise to the present-day anomalies inferred by global tomography models. To address this question, we present 3-D convection models in compressible and self-gravitating mantle initialised by different hypothetical temperature patterns. A notable feature of our forward convection modelling is the use of self-consistent coupling of the motion of surface tectonic plates to the underlying mantle flow, without imposing prescribed surface velocities (i.e., plate-like boundary condition. As an approximation for the surface mechanical conditions before plate tectonics began to operate we employ the no-slip (rigid boundary condition. A rigid boundary condition demonstrates that the initial thermally-dominated structure is preserved, and its geographical location is fixed during the evolution of mantle flow. Considering the impact of different assumed surface boundary conditions (rigid and plate-like on the evolution of thermal heterogeneity in the mantle we suggest that the intrinsic buoyancy of seven superplumes is most-likely resolved in the tomographic images of present-day mantle thermal structure. Our convection simulations with a plate-like boundary condition reveal that the evolution of an initial cold anomaly beneath the Java-Indonesian trench system yields a long-term, stable pattern of thermal heterogeneity in the lowermost mantle that resembles the present-day Large Low Shear Velocity Provinces (LLSVPs, especially below the Pacific. The evolution of subduction zones may be, however, influenced by the mantle-wide flow driven by deeply-rooted and long-lived superplumes since Archean times. These convection models also detect the intrinsic buoyancy of the Perm Anomaly that has been identified as a unique

  1. Structural and metamorphic evolution of the Turku migmatite complex, southwestern Finland

    Directory of Open Access Journals (Sweden)

    Väisänen, M.

    1999-06-01

    Full Text Available The Turku migmatite complex in southwestern Finland is a representative area for the type of tectonic and metamorphic evolution seen within the Palaeoproterozoic Svecofennian Orogen in southern Finland. The orogeny can be divided into early, late and postorogenic stages. The early orogenic structural evolution of the crust is expressed by a D1/D2 deformation recorded as bedding-parallel S1 mica foliation deformed by tight to isoclinal D2 folds with subhorizontal axial planes and a penetrative S2 axial plane foliation. Syntectonic ca. 1890-1870 Ma tonalites were emplaced during D2 as sheet intrusions. This deformation is attributed to thrust tectonics and thickening of the crust. The late orogenic structural evolution produced the main D3 folding, which transposed previous structures into a NE-SW trend. The doubly plunging fold axis produced dome-and-basin structures. The attitude of the F3 folds varies from upright or slightly overturned to locally recumbent towards the NW. Granite dikes were intruded along S3 axial planes. Large D3 fold limbs are often strongly deformed, intensively migmatized and intruded by garnet- and cordierite-bearing granites. These observations suggest that these potassium-rich granites, dated at 1840-1830 Ma, were emplaced during D3. This late orogenic NW-SE crustal shortening further contributed to crustal thickening. Subvertical D4 shear zones that cut all previous rock types possibly controlled the emplacement of postorogenic granitoids. Steeply plunging lineations on D4 shear planes suggest vertical displacements during a regional uplift stage. Metamorphic grade increases from cordierite-sillimanite-K-feldspar gneisses in the northwest and from muscovite-quartz±andalusite rocks in the southeast to high-temperature granulite facies migmatites in the middle of the study area. Block movements during D4 caused the observed differences in metamorphic grade. Garnet and cordierite are mostly breakdown products of biotite

  2. The structural evolution and diffusion during the chemical transformation from cobalt to cobalt phosphide nanoparticles

    KAUST Repository

    Ha, Don-Hyung

    2011-01-01

    We report the structural evolution and the diffusion processes which occur during the phase transformation of nanoparticles (NPs), ε-Co to Co 2P to CoP, from a reaction with tri-n-octylphosphine (TOP). Extended X-ray absorption fine structure (EXAFS) investigations were used to elucidate the changes in the local structure of cobalt atoms which occur as the chemical transformation progresses. The lack of long-range order, spread in interatomic distances, and overall increase in mean-square disorder compared with bulk structure reveal the decrease in the NP\\'s structural order compared with bulk structure, which contributes to their deviation from bulk-like behavior. Results from EXAFS show both the Co2P and CoP phases contain excess Co. Results from EXAFS, transmission electron microscopy, X-ray diffraction, and density functional theory calculations reveal that the inward diffusion of phosphorus is more favorable at the beginning of the transformation from ε-Co to Co2P by forming an amorphous Co-P shell, while retaining a crystalline cobalt core. When the major phase of the sample turns to Co 2P, the diffusion processes reverse and cobalt atom out-diffusion is favored, leaving a hollow void, characteristic of the nanoscale Kirkendall effect. For the transformation from Co2P to CoP theory predicts an outward diffusion of cobalt while the anion lattice remains intact. In real samples, however, the Co-rich nanoparticles continue Kirkendall hollowing. Knowledge about the transformation method and structural properties provides a means to tailor the synthesis and composition of the NPs to facilitate their use in applications. © 2011 The Royal Society of Chemistry.

  3. Analysis of quantum structures using ion microbeam

    International Nuclear Information System (INIS)

    Chakraborty, Purushottam

    2007-01-01

    The fundamental challenge in surface analysis is the quantitative characterization of the elemental composition and chemical structure of surfaces with the highest sensitivity and spatial resolution. The flexibility of sputter sectioning, in combination with the principal advantages of the mass spectrometric techniques, such as large dynamic ranges both in the mass separation and detection systems, has enabled the dynamic Secondary Ion Mass spectrometry (SIMS) to be an extremely sensitive technique for the analysis of solid surfaces and thin films. SIMS depth profiling is now possible at depth resolutions down to ∼ 2 nm with quantification data obtainable from the topmost atomic layer onwards into the depth. The interface widths obtained from depth profiles are related to the induced surface roughness at the interfaces. With optimized ion bombardment conditions, like extremely low beam currents (down to ∼ 10 nA), low ion energies (below 1 keV) and appropriate impact angles, ultra-high resolution SIMS depth profiling has enabled interfacial composition analysis of ultra-thin films, quantum wells, hetero-structures, etc. and complex low-dimensional structures with high precision and repeatability. The talk will address some of our recent experiments on high depth- resolution SIMS analysis of Bragg mirrors, quantum wells and interface alloying in metallic multilayer structures. (author)

  4. Term Structure Analysis with Big Data

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Rudebusch, Glenn D.

    Analysis of the term structure of interest rates almost always takes a two-step approach. First, actual bond prices are summarized by interpolated synthetic zero-coupon yields, and second, a small set of these yields are used as the source data for further empirical examination. In contrast, we...

  5. Synthesis, crystal structure, thermal analysis and dielectric

    Indian Academy of Sciences (India)

    Annual Meetings · Mid Year Meetings · Discussion Meetings · Public Lectures · Lecture Workshops · Refresher Courses · Symposia · Live Streaming. Home; Journals; Bulletin of Materials Science; Volume 39; Issue 5. Synthesis, crystal structure, thermal analysis and dielectric properties of two mixed trichlorocadmiates (II).

  6. The diverse crustal structure and magmatic evolution of the Manihiki Plateau, central Pacific

    Science.gov (United States)

    Hochmuth, K.; Gohl, K.; Uenzelmann-Neben, G.; Werner, R.

    2014-07-01

    The Manihiki Plateau is a Large Igneous Province (LIP) in the central Pacific. It was emplaced as part of the "Super-LIP" Ontong Java Nui and experienced fragmentation into three sub-plateaus, possibly during the break-up of Ontong Java Nui. The Manihiki Plateau is presumably the centerpiece of this "Super-LIP" and its investigation can therefore decipher the break-up mechanisms as well as the evolution of the plateau after its initial emplacement. By analyzing two seismic refraction/wide-angle reflection profiles crossing the two largest sub-plateaus of the Manihiki Plateau, the High Plateau and the Western Plateaus, we give new insights into their crustal structure and magmatic evolution. The High Plateau shows a crustal structure of 20 km thickness and a seismic P wave velocity distribution, which is comparable to other LIPs. The High Plateau experienced a strong secondary volcanism, which can be seen in relicts of seamount chain volcanism. The Western Plateaus on the other hand show no extensive secondary volcanism and are mainly structured by fault systems and sedimentary basins. A constant decrease in Moho depth (9-17 km) is a further indicator of crustal stretching on the Western Plateaus. Those findings lead to the conclusion, that the two sub-plateaus of the Manihiki Plateau experienced a different magmatic and tectonic history. Whereas the High Plateau experienced a secondary volcanism, the Western Plateaus underwent crustal stretching during and after the break-up of Ontong Java Nui. This indicates, that the sub-plateaus of the Manihiki Plateau play an individual part in the break-up history of Ontong Java Nui.

  7. Evolution of the hourglass structures in the Laminaria High, Timor Sea: Implications for hydrocarbon traps

    Science.gov (United States)

    Çiftçi, N. Bozkurt; Langhi, Laurent

    2012-03-01

    In cross-section, an hourglass structure can be visualized as an older horst block and superimposed, younger graben. Bounding faults of the horst and graben blocks represent separate conjugate fault systems formed by two distinct episodes of extension in the Timor Sea during Late Jurassic-Early Cretaceous (1st-phase) and Middle Miocene - Pliocene (2nd-phase); with an ∼120 My hiatus of limited or no fault activity in-between. Horst blocks were formed by the 1st-phase of extension and buried post-deformation. With the onset of the 2nd-phase of extension, the hourglass geometry began to form by nucleation of the graben-bounding faults in the shallow sedimentary section, in isolation from the horst-bounding faults. Location of the graben is biased by the buried horst block and graben-bounding faults grew down-dip from the shallow locus of nucleation toward the underlying horst block on which only minor reactivation occurred. Detachment of the two systems in this way was predominantly controlled by the first-order mechanical layering. A thick, shale-rich, ductile layer separates the horst- and graben-bounding fault systems and acts as a barrier to vertical fault propagation. Confinement of the graben-bounding faults into the shallow section was also facilitated by outer-arc style extension due to lithospheric flexure controlling the 2nd-phase strain in the region. The complex evolution history and the composite nature of the hourglass structures resulted in systematic along-dip variation of displacement. This variation predominantly relates to syn-kinematic deposition and location of fault tips that are controlled by the ductile layer. The presented evolution model of the hourglass structures concentrates fault tips and related stress perturbation onto the top seal and is likely to be detrimental to top-seal integrity.

  8. Atmospheric reaction systems as null-models to identify structural traces of evolution in metabolism.

    Directory of Open Access Journals (Sweden)

    Petter Holme

    Full Text Available The metabolism is the motor behind the biological complexity of an organism. One problem of characterizing its large-scale structure is that it is hard to know what to compare it to. All chemical reaction systems are shaped by the same physics that gives molecules their stability and affinity to react. These fundamental factors cannot be captured by standard null-models based on randomization. The unique property of organismal metabolism is that it is controlled, to some extent, by an enzymatic machinery that is subject to evolution. In this paper, we explore the possibility that reaction systems of planetary atmospheres can serve as a null-model against which we can define metabolic structure and trace the influence of evolution. We find that the two types of data can be distinguished by their respective degree distributions. This is especially clear when looking at the degree distribution of the reaction network (of reaction connected to each other if they involve the same molecular species. For the Earth's atmospheric network and the human metabolic network, we look into more detail for an underlying explanation of this deviation. However, we cannot pinpoint a single cause of the difference, rather there are several concurrent factors. By examining quantities relating to the modular-functional organization of the metabolism, we confirm that metabolic networks have a more complex modular organization than the atmospheric networks, but not much more. We interpret the more variegated modular arrangement of metabolism as a trace of evolved functionality. On the other hand, it is quite remarkable how similar the structures of these two types of networks are, which emphasizes that the constraints from the chemical properties of the molecules has a larger influence in shaping the reaction system than does natural selection.

  9. Structural reliability analysis and seismic risk assessment

    International Nuclear Information System (INIS)

    Hwang, H.; Reich, M.; Shinozuka, M.

    1984-01-01

    This paper presents a reliability analysis method for safety evaluation of nuclear structures. By utilizing this method, it is possible to estimate the limit state probability in the lifetime of structures and to generate analytically the fragility curves for PRA studies. The earthquake ground acceleration, in this approach, is represented by a segment of stationary Gaussian process with a zero mean and a Kanai-Tajimi Spectrum. All possible seismic hazard at a site represented by a hazard curve is also taken into consideration. Furthermore, the limit state of a structure is analytically defined and the corresponding limit state surface is then established. Finally, the fragility curve is generated and the limit state probability is evaluated. In this paper, using a realistic reinforced concrete containment as an example, results of the reliability analysis of the containment subjected to dead load, live load and ground earthquake acceleration are presented and a fragility curve for PRA studies is also constructed

  10. Microstructural evolution of uranium dioxide following compression creep tests: An EBSD and image analysis study

    Energy Technology Data Exchange (ETDEWEB)

    Iltis, X., E-mail: xaviere.iltis@cea.fr [CEA, DEN, DEC, Cadarache, 13108 Saint-Paul-Lez-Durance (France); Gey, N. [Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), CNRS UMR 7239, Université de Lorraine, Ile du Saulcy, 57045 Metz Cedex 1 (France); Cagna, C. [CEA, DEN, DEC, Cadarache, 13108 Saint-Paul-Lez-Durance (France); Hazotte, A. [Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), CNRS UMR 7239, Université de Lorraine, Ile du Saulcy, 57045 Metz Cedex 1 (France); Sornay, Ph. [CEA, DEN, DEC, Cadarache, 13108 Saint-Paul-Lez-Durance (France)

    2015-01-15

    Highlights: • Image analysis and EBSD are performed on creep tested UO{sub 2} pellets. • Development of intergranular voids, with increasing strain, is quantified. • EBSD evidences a sub-structuration process within the grains and quantifies it. • Creep mechanisms are discussed on the basis of these results. - Abstract: Sintered UO{sub 2} pellets with relatively large grains (∼25 μm) are tested at 1500 °C under a compressive stress of 50 MPa, at different deformation levels up to 12%. Electron Back Scattered Diffraction (EBSD) is used to follow the evolution, with deformation, of grains (size, shape, orientation) and sub-grains. Image analyses of SEM images are performed to characterize emergence of a population of micron size voids. For the considered microstructure and test conditions, the results show that the deformation process of UO{sub 2} globally corresponds to grain boundary sliding, partly accommodated by a dislocational creep within the grains, leading to a highly sub-structured state.

  11. Paleogeographic evolution of carbonate reservoirs: geological and geophysical analysis at the Albian Campos Basin, Brazil

    Science.gov (United States)

    Castillo Vincentelli, Maria Gabriela; Favoreto, Julia; Roemers-Oliveira, Eduardo

    2018-02-01

    An integrated geophysical and geological analysis of a carbonate reservoir can offer an effective method to better understand the paleogeographical evolution and distribution of a geological reservoir and non-reservoir facies. Therefore, we propose a better method for obtaining geological facies from geophysical facies, helping to characterize the permo-porous system of this kind of play. The goal is to determine the main geological phases from a specific hydrocarbon producer (Albian Campos Basin, Brazil). The applied method includes the use of a petrographic and qualitative description from the integrated reservoir with seismic interpretation of an attribute map (energy, root mean square, mean amplitude, maximum negative amplitude, etc), all calculated at the Albian level for each of the five identified phases. The studied carbonate reservoir is approximately 6 km long with a main direction of NE-SW, and it was sub-divided as follows (from bottom to top): (1) the first depositional sequence of the bank was composed mainly of packstone, indicating that the local structure adjacent to the main bank is protected from environmental conditions; (2) characterized by the presence of grainstone developed at the higher structure; (3) the main sequence of the peloidal packstone with mudstones oncoids; (4) corresponds to the oil production of carbonate reservoirs formed by oolitic grainstone deposited at the top of the carbonate bank; at this phase, rising sea levels formed channels that connected the open sea shelf with the restricted circulation shelf; and (5) mudstone and wackestone represent the system’s flooding phase.

  12. Earthquake response analysis considering structure-soil-structure interaction

    International Nuclear Information System (INIS)

    Shiomi, T.; Takahashi, K.; Oguro, E.

    1981-01-01

    This paper proposes a numerical method of earthquake response analysis considering the structure-soil-structure interaction between two adjacent buildings. In this paper an analytical study is presented in order to show some typical features of coupling effects of two reactor buildings of the BWR-type nuclear power plant. The technical approach is a kind of substructure method, which at first evaluates the compliance properties with the foundation-soil-foundation interaction and then uses the compliance in determining seismic responses of two super-structures during earthquake motions. For this purpose, it is assumed that the soil medium is an elastic half space for modeling and that the rigidity of any type of structures such as piping facilities connecting the adjacent buildings is negligible. The technical approach is mainly based on the following procedures. Supersturcture stiffness is calculated by using the method which has been developed in our laboratory based on the Thin-Wall Beam Theory. Soil stiffness is expressed by a matrix with 12 x 12 elements as a function of frequency, which is calculated using the soil compliance functions proposed in Dr. Tajimi's Theory. These stiffness values may be expressed by complex numbers for modeling the damping mechanism of superstructures. We can solve eigenvalue problems with frequency dependent stiffness and the large-scale matrix using our method which is based on condensing the matrix to the suitable size by Rayleigh-Ritz method. Earthquake responses can be solved in the frequency domain by Fourier Transform. (orig./RW)

  13. Uncertain structural dynamics of aircraft panels and fuzzy structures analysis

    Science.gov (United States)

    Sparrow, Victor W.; Buehrle, Ralph D.

    2002-11-01

    Aircraft fuselage panels, seemingly simple structures, are actually complex because of the uncertainty of the attachments of the frame stiffeners and longitudinal stringers. It is clearly important to understand the dynamics of these panels because of the subsequent radiation into the passenger cabin, even when complete information is not available for all portions of the finite-element model. Over the last few years a fuzzy structures analysis (FSA) approach has been undertaken at Penn State and NASA Langley to quantify the uncertainty in modeling aircraft panels. A new MSC.Nastran [MSC.Software Corp. (Santa Ana, CA)] Direct Matrix Abstraction Program (DMAP) code was written and tested [AIAA paper 2001-1320, 42nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conf., Seattle, WA, 16 April 2001] and was applied to simple fuselage panel models [J. Acoust. Soc. Am. 109, 2410(A) (2001)]. Recently the work has focused on understanding the dynamics of a realistic aluminum fuselage panel, typical of today's aircraft construction. This presentation will provide an overview of the research and recent results will be given for the fuselage panel. Comparison between experiments and the FSA results will be shown for different fuzzy input parameters. [Work supported by NASA Research Cooperative Agreement NCC-1-382.

  14. The Structural Evolution and Segregation in a Dual Alloy Ingot Processed by Electroslag Remelting

    Directory of Open Access Journals (Sweden)

    Yu Liu

    2016-12-01

    Full Text Available The structural evolution and segregation in a dual alloy made by electroslag remelting (ESR was investigated by various analytical techniques. The results show that the macrostructure of the ingot consists of two crystallization structures: one is a quite narrow, fine, equiaxed grain region at the edge and the other is a columnar grain region, which plays a leading role. The typical columnar structure shows no discontinuity between the CrMoV, NiCrMoV, and transition zones. The average secondary arm-spacing is coarsened from 35.3 to 49.2 μm and 61.5 μm from the bottom to the top of the ingot. The distinctive features of the structure are attributed to the different cooling conditions during the ESR process. The Ni, Cr, and C contents markedly increase in the transition zone (TZ and show a slight increase from the bottom to the top and from the surface to the center of the ESR ingot due to the partition ratios, gravity segregation, the thermal buoyancy flow, the solutal buoyancy flow, and the inward Lorentz force. Less dendrite segregation exists in the CrMoV zone and the transition zone due to a stronger cooling rate (11.1 and 4.5 °C/s and lower Cr and C contents. The precipitation of carbides was observed in the ingot due to a lower solid solubility of the carbon element in the α phase.

  15. Genome-Wide Analysis Characterization and Evolution of SBP Genes in Fragaria vesca, Pyrus bretschneideri, Prunus persica and Prunus mume

    Directory of Open Access Journals (Sweden)

    Muhammad Abdullah

    2018-03-01

    Full Text Available The SQUAMOSA promoter binding protein (SBP-box proteins are plant-specific transcriptional factors in plants. SBP TFs are known to play important functions in a diverse development process and also related in the process of evolutionary novelties. SBP gene family has been characterized in several plant species, but little is known about molecular evolution, functional divergence and comprehensive study of SBP gene family in Rosacea. We carried out genome-wide investigations and identified 14, 32, 17, and 17 SBP genes from four Rosacea species (Fragaria vesca, Pyrus bretschneideri, Prunus persica and Prunus mume, respectively. According to phylogenetic analysis arranged the SBP protein sequences in seven groups. Localization of SBP genes presented an uneven distribution on corresponding chromosomes of Rosacea species. Our analyses designated that the SBP genes duplication events (segmental and tandem and divergence. In addition, due to highly conserved structure pattern of SBP genes, recommended that highly conserved region of microsyneteny in the Rosacea species. Type I and II functional divergence was detected among various amino acids in SBP proteins, while there was no positive selection according to substitutional model analysis using PMAL software. These results recommended that the purifying selection might be leading force during the evolution process and dominate conservation of SBP genes in Rosacea species according to environmental selection pressure analysis. Our results will provide basic understanding and foundation for future research insights on the evolution of the SBP genes in Rosacea.

  16. The vertebrate RCAN gene family: novel insights into evolution, structure and regulation.

    Directory of Open Access Journals (Sweden)

    Eva Serrano-Candelas

    Full Text Available Recently there has been much interest in the Regulators of Calcineurin (RCAN proteins which are important endogenous modulators of the calcineurin-NFATc signalling pathway. They have been shown to have a crucial role in cellular programmes such as the immune response, muscle fibre remodelling and memory, but also in pathological processes such as cardiac hypertrophy and neurodegenerative diseases. In vertebrates, the RCAN family form a functional subfamily of three members RCAN1, RCAN2 and RCAN3 whereas only one RCAN is present in the rest of Eukarya. In addition, RCAN genes have been shown to collocate with RUNX and CLIC genes in ACD clusters (ACD21, ACD6 and ACD1. How the RCAN genes and their clustering in ACDs evolved is still unknown. After analysing RCAN gene family evolution using bioinformatic tools, we propose that the three RCAN vertebrate genes within the ACD clusters, which evolved from single copy genes present in invertebrates and lower eukaryotes, are the result of two rounds of whole genome duplication, followed by a segmental duplication. This evolutionary scenario involves the loss or gain of some RCAN genes during evolution. In addition, we have analysed RCAN gene structure and identified the existence of several characteristic features that can be involved in RCAN evolution and gene expression regulation. These included: several transposable elements, CpG islands in the 5' region of the genes, the existence of antisense transcripts (NAT associated with the three human genes, and considerable evidence for bidirectional promoters that regulate RCAN gene expression. Furthermore, we show that the CpG island associated with the RCAN3 gene promoter is unmethylated and transcriptionally active. All these results provide timely new insights into the molecular mechanisms underlying RCAN function and a more in depth knowledge of this gene family whose members are obvious candidates for the development of future therapies.

  17. Origin and Evolution of Magnetic Field in PMS Stars: Influence of Rotation and Structural Changes

    International Nuclear Information System (INIS)

    Emeriau-Viard, Constance; Brun, Allan Sacha

    2017-01-01

    During stellar evolution, especially in the pre-main-sequence phase, stellar structure and rotation evolve significantly, causing major changes in the dynamics and global flows of the star. We wish to assess the consequences of these changes on stellar dynamo, internal magnetic field topology, and activity level. To do so, we have performed a series of 3D HD and MHD simulations with the ASH code. We choose five different models characterized by the radius of their radiative zone following an evolutionary track computed by a 1D stellar evolution code. These models characterized stellar evolution from 1 to 50 Myr. By introducing a seed magnetic field in the fully convective model and spreading its evolved state through all four remaining cases, we observe systematic variations in the dynamical properties and magnetic field amplitude and topology of the models. The five MHD simulations develop a strong dynamo field that can reach an equipartition state between the kinetic and magnetic energies and even superequipartition levels in the faster-rotating cases. We find that the magnetic field amplitude increases as it evolves toward the zero-age main sequence. Moreover, the magnetic field topology becomes more complex, with a decreasing axisymmetric component and a nonaxisymmetric one becoming predominant. The dipolar components decrease as the rotation rate and the size of the radiative core increase. The magnetic fields possess a mixed poloidal-toroidal topology with no obvious dominant component. Moreover, the relaxation of the vestige dynamo magnetic field within the radiative core is found to satisfy MHD stability criteria. Hence, it does not experience a global reconfiguration but slowly relaxes by retaining its mixed stable poloidal-toroidal topology.

  18. Origin and Evolution of Magnetic Field in PMS Stars: Influence of Rotation and Structural Changes

    Energy Technology Data Exchange (ETDEWEB)

    Emeriau-Viard, Constance; Brun, Allan Sacha, E-mail: constance.emeriau@cea.fr, E-mail: sacha.brun@cea.fr [Laboratoire AIM Paris-Saclay CEA/DSM—CNRS—Université Paris Diderot, IRFU/DAp CEA Paris-Saclay, F-91191 Gif-sur-Yvette Cedex (France)

    2017-09-01

    During stellar evolution, especially in the pre-main-sequence phase, stellar structure and rotation evolve significantly, causing major changes in the dynamics and global flows of the star. We wish to assess the consequences of these changes on stellar dynamo, internal magnetic field topology, and activity level. To do so, we have performed a series of 3D HD and MHD simulations with the ASH code. We choose five different models characterized by the radius of their radiative zone following an evolutionary track computed by a 1D stellar evolution code. These models characterized stellar evolution from 1 to 50 Myr. By introducing a seed magnetic field in the fully convective model and spreading its evolved state through all four remaining cases, we observe systematic variations in the dynamical properties and magnetic field amplitude and topology of the models. The five MHD simulations develop a strong dynamo field that can reach an equipartition state between the kinetic and magnetic energies and even superequipartition levels in the faster-rotating cases. We find that the magnetic field amplitude increases as it evolves toward the zero-age main sequence. Moreover, the magnetic field topology becomes more complex, with a decreasing axisymmetric component and a nonaxisymmetric one becoming predominant. The dipolar components decrease as the rotation rate and the size of the radiative core increase. The magnetic fields possess a mixed poloidal-toroidal topology with no obvious dominant component. Moreover, the relaxation of the vestige dynamo magnetic field within the radiative core is found to satisfy MHD stability criteria. Hence, it does not experience a global reconfiguration but slowly relaxes by retaining its mixed stable poloidal-toroidal topology.

  19. Structural evolution of silica nanoparticles in water-in- oil microemulsions

    International Nuclear Information System (INIS)

    Bush, A.J.; Bartlett, J.R.; Finnie, K.S.; Schultz, J.; Kong, L.; Larkin, M.; Barbe, C.J.

    2003-01-01

    Full text: The controlled release of drugs, encapsulated within nanoparticles, has been achieved by a variety of microencapsulation techniques, including, liposomes, hydrogels and polymeric materials, which are based on organic carrier systems. We have been studying inorganic nanoparticles as they possess several intrinsic advantages as drug carriers for in-vivo applications. In particular, they are biologically inert, intrinsically hydrophilic and exhibit a long shelf life in the 'dry' state. Recently, we have developed a suite of sol-gel techniques for producing nanoparticulate silica containing encapsulated bioactive species using water-in-oil microemulsions. The internal nanostructure of the gels (pore volume, size and tortuosity, and surface chemistry), which controls the release kinetics of the bioactive species, can be precisely tailored by varying such sol-gel processing parameters as the water-to-alkoxide ratio, pH, alkoxide concentration, ageing, and drying conditions. Prior to encapsulation of the drug it is vital to understand the mechanism of particle formation. The effect of processing parameters, such as the pH of the aqueous core on the mechanism and kinetics of reactions occurring during nanoparticle evolution, have been investigated. Scattering methods including SANS, SAXS and light scattering, in conjunction with complementary spectroscopic techniques, have been used to probe the evolution of silica nanoparticle structure during the hydrolysis and condensation of tetramethylorthosilicate (TMOS) within the aqueous core of the w/o microemulsions. Photon correlation spectroscopy has revealed the micelle diameter to be 10-12nm. Particle evolution at various pH was monitored using SANS and the rate of hydrolysis has been studied with FTIR, revealing that particle formation appears to be more rapid in base than in acid conditions

  20. Numerical Limit Analysis of Precast Concrete Structures

    DEFF Research Database (Denmark)

    Herfelt, Morten Andersen

    . The strength and efficiency of the presented framework are demonstrated by two real size examples, a two-dimensional precast shear wall and a three-dimensional precast concrete stairwell. The analysis shows that the framework is capable of modelling complex precast concrete structures efficiently. Moreover......Precast concrete elements are widely used in the construction industry as they provide a number of advantages over the conventional in-situ cast concrete structures. Joints cast on the construction site are needed to connect the precast elements, which poses several challenges. Moreover....... The scope is to be able to model entire precast concrete structures while accounting for the local behaviour of the joints. The in-situ cast joints are crucial to the capacity of precast concrete structures, however, the behaviour of joints is in practice assessed by simple, empirical design formulas...