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. Techniques of Turnovers’ Evolution and Structure Analysis Using SQL Server 2005

    Directory of Open Access Journals (Sweden)

    Alexandru Manole

    2007-07-01

    Full Text Available The turnovers’ evolution and structure analysis can provide many useful information for the construction of a viable set of policies for products, prices and retail network. When the analysis deals with large quantities of raw data, one of the solutions that guarantees the rigorous treatment of the data is the use of a software system based on a data warehouse.

  3. 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

  4. 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…

  5. 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.

  6. Analysis on the Evolution of Agricultural Structure about Pan-Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    DAI Jiang; LIU Zhi-ying

    2010-01-01

    Starting from the definition of agricultural structure,this paper firstly analyzes the change of industrial and spatial structure of agriculture of Pan-Yangtze River Delta,then inspects the relationship between the development of economics and the evolution of agricultural structure,an the end it provides policy recommendation about the development and adjustment of agricultural structure for the future.

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

    CERN Document Server

    Puccio, Elena; Piilo, Jyrki; Tumminello, Michele

    2016-01-01

    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...

  8. 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.

  9. Structural Analysis and Visualization of C++ Code Evolution using Syntax Trees

    NARCIS (Netherlands)

    Chevalier, Fanny; Auber, David; Telea, Alexandru

    2007-01-01

    We present a method to detect and visualize evolution patterns in C++ source code. Our method consists of three steps. First, we extract an annotated syntax tree (AST) from each version of a given C++ source code. Next, we hash the extracted syntax nodes based on a metric combining structure and typ

  10. 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 prop

  11. Structure Model of Urban Traffic System Evolution

    Institute of Scientific and Technical Information of China (English)

    JIANG Ke-jin; ZHANG Dian-ye

    2008-01-01

    A structure model of urban traffic system evolution is built based on the analysis of the factors influencing the system evolution and the hierarchy between the factors. Then the influencing degrees of the factors are quantificationally analyzed by DEMATE (decision making trial and evaluation laboratory). The analysis results indicate that the traffic mode structure which achieves the highest central degree is the dominant influencing factor of the urban traffic system evolution, and that economy development and the traffic poficy axe the second important factors that also affect the traffic mode structures. Furthermore, physical geography is a basic restriction to the urban traffic system evolution.

  12. 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.

  13. Structural Analysis and Visualization of C++ Code Evolution using Syntax Trees

    OpenAIRE

    Chevalier, Fanny; Auber, David; Telea, Alexandru

    2007-01-01

    International audience; We present a method to detect and visualize evolution patterns in C++ source code. Our method consists of three steps. First, we extract an annotated syntax tree (AST) from each version of a given C++ source code. Next, we hash the extracted syntax nodes based on a metric combining structure and type information, and construct matches (correspondences) between similar-hash subtrees. Our technique detects code fragments which have not changed, or changed little, during ...

  14. 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...

  15. 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.)

  16. Fractal parameterization analysis of ferroelectric domain structure evolution induced by electron beam irradiation

    Science.gov (United States)

    Maslovskaya, A. G.; Barabash, T. K.

    2017-01-01

    The article presents some results of fractal analysis of ferroelectric domain structure images visualized with scanning electron microscope (SEM) techniques. The fractal and multifractal characteristics were estimated to demonstrate self-similar organization of ferroelectric domain structure registered with static and dynamic contrast modes of SEM. Fractal methods as sensitive analytical tools were used to indicate degree of domain structure and domain boundary imperfections. The electron irradiation-induced erosion effect of ferroelectric domain boundaries in electron beam-stimulated polarization current mode of SEM is characterized by considerable raising of fractal dimension. For dynamic contrast mode of SEM there was revealed that complication of domain structure during its dynamics is specified by increase in fractal dimension of images and slight raising of boundary fractal dimension.

  17. 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.

  18. Structural evolution of nanoscale metallic glasses during high-pressure torsion: A molecular dynamics analysis

    Science.gov (United States)

    Feng, S. D.; Jiao, W.; Jing, Q.; Qi, L.; Pan, S. P.; Li, G.; Ma, M. Z.; Wang, W. H.; Liu, R. P.

    2016-11-01

    Structural evolution in nanoscale Cu50Zr50 metallic glasses during high-pressure torsion is investigated using molecular dynamics simulations. Results show that the strong cooperation of shear transformations can be realized by high-pressure torsion in nanoscale Cu50Zr50 metallic glasses at room temperature. It is further shown that high-pressure torsion could prompt atoms to possess lower five-fold symmetries and higher potential energies, making them more likely to participate in shear transformations. Meanwhile, a higher torsion period leads to a greater degree of forced cooperative flow. And the pronounced forced cooperative flow at room temperature under high-pressure torsion permits the study of the shear transformation, its activation and characteristics, and its relationship to the deformations behaviors. This research not only provides an important platform for probing the atomic-level understanding of the fundamental mechanisms of high-pressure torsion in metallic glasses, but also leads to higher stresses and homogeneous flow near lower temperatures which is impossible previously.

  19. Metagenomic analysis of microbiota structure evolution in phytoremediation of a swine lagoon wastewater.

    Science.gov (United States)

    Ye, Jianfeng; Song, Zhaofeng; Wang, Liang; Zhu, Jun

    2016-11-01

    Pytoremediation was studied in this project to treat swine manure lagoon wastewater characteristic of high concentrations of organic carbon, ammonium (N) and phosphorus (P). The impacts of introducing exogenous microalgae Chlorella into the lagoon wastewater on the removal of major nutrients and the transformation of the native wastewater microbiota structure were explored under two phytoremediation modes (shake flask and CO2-air bubbling). The results showed that the inoculation of microalgae could significantly enhance N and P removal. Metagenomic analysis of the native microbiota composition in the wastewater affected by algae inoculation revealed that a substantial population of algicidal bacteria was developed in the shake flask system, while in the CO2-air bubbling system, a niche for more mutualistic bacteria was created, which benefited the maximal algal growth with the simultaneous optimal N and P removal. To our knowledge, this study presents, the first reported case of applying metagenomic approach to a phytoremediation system treating real swine lagoon wastewater.

  20. Morphotectonic analysis, structural evolution/pattern of a contractional ridge: Giouchtas Mt., Central Crete, Greece

    Indian Academy of Sciences (India)

    Kokinou Eleni; Skilodimou Hariklia D; Bathrellos George D; Antonarakou Assimina; Kamberis Evangelos

    2015-04-01

    The Giouchtas Mountain is situated south of Heraklion, Central Crete. It is a N–S trending morphological asymmetric ridge with a steep western slope, whilst its eastern slope is characterized by a smoother relief, composed of Mesozoic limestone and Eocene–lower Oligocene flysch of the Gavrovo–Tripolis zone. 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 of the area. Geomorphic indices, used in the present study, are the mountain front sinuosity index (Smf) and the valley floor/width ratio index (Vf). Based on Smf and Vf values, it is implied that this area can be assigned to a tectonic class I, corresponding to higher tectonic activity. However, spatial variations of the tectonic activity along the segmented fronts point to a general trend of increasing activity towards the north and especially, northeast. The model of this possibly active structural feature corresponds to a compressional mechanism followed by an earliest Mid. Miocene to Holocene late-stage deformation related to extensional faulting.

  1. Structural analysis and evolution of specificity of the SUMO UFD E1-E2 interactions

    Science.gov (United States)

    Liu, Bing; Lois, L. Maria; Reverter, David

    2017-01-01

    SUMO belongs to the ubiquitin-like family (UbL) of protein modifiers. SUMO is conserved among eukaryotes and is essential for the regulation of processes such as DNA damage repair, transcription, DNA replication and mitosis. UbL modification of proteins occurs via a specific enzymatic cascade formed by the crosstalk between the E1-activating enzyme, the E2-conjugating enzyme and the E3-ligase. An essential discrimination step in all UbL modifiers corresponds to the interaction between E1 and E2 enzymes, which is mediated by the recruitment of the E2 to the UFD domain (Ubiquitin-Fold Domain) of the E1 enzyme. To gain insights in the properties of this interface, we have compared the structures of the complexes between E1 UFD domain and E2 in human and yeast, revealing two alternative UFD platforms that interact with a conserved E2. Comparative sequence analysis of the E1 UFD domain indicates that the E2 binding region has been conserved across phylogenetic closely related species, in which higher sequence conservation can be found in the E2 binding region than in the entire UFD domain. These distinctive strategies for E1-E2 interactions through the UFD domain might be the consequence of a high selective pressure to ensure specificity of each modifier conjugation system. PMID:28165030

  2. Structure evolution in electrorheological fluids

    Science.gov (United States)

    Qian, Bian; Helal, Ahmed; Telleria, Maria; Murphy, Mike; Strauss, Marc; McKinley, Gareth; Hosoi, Anette

    2012-11-01

    Enhanced knowledge of the transient behavior and characteristics of electrorheological (ER) fluids subject to time dependent electric fields carries the potential to advance the design of fast actuated hydraulic devices. In this study, the dynamic response of electrorheological fluid flows in rectilinear microchannels was investigated experimentally. Using high-speed microscopic imaging, the evolution of particle aggregates in ER fluids subjected to temporally stepwise electric fields was visualized. Nonuniform growth of the particle structures in the channel was observed and correlated to field strength and flow rate. Two competing time scales for structure growth were identified. Guided by experimental observations, we develop a phenomenological model to quantitatively describe and predict the evolution of microscale structures and the concomitant induced pressure gradient. This work is supported by DARPA M3.

  3. Analysis of grain structure evolution based on optical measurements of mc Si wafers

    Science.gov (United States)

    Strauch, Theresa; Demant, Matthias; Krenckel, Patricia; Riepe, Stephan; Rein, Stefan

    2016-11-01

    Grain structure and grain competition have a strong impact on bulk lifetime in multicrystalline (mc) silicon. A fast and thorough characterization of grain structure is crucial in order to improve industrial crystal growth. This work introduces key parameters of grain structure, extracted with a newly developed image processing tool. Four bricks grown with different concepts were chosen to investigate the value of the identified key parameters and to identify characteristic developments along the brick. Optical measurements on as-cut wafers from these bricks serve as a basis to extract grain structure properties, i.e., size, shape, homogeneity and distribution of grain size. By connecting the 2D-information over brick height, a statistical insight into the entire brick is gained. Weighted percentiles of grain area offer a robust measure to characterize grain size distribution. As twinning has a large impact on grain competition, twinned grains are detected via grain shape. Additionally, regions with strong grain competition are highlighted for investigations on grain overgrowth. It is found that the share of twin grains increases with brick height in high-performance mc (HPM) silicon with fine-granular seeds from almost zero up to about 15% whereas it remains rather constant over the whole brick height in standard mc-Si. The results of the investigated bricks show clearly that towards the brick top, the material differences in grain size decrease. This suggests that an energetically favorable state may exist for grain structure development.

  4. Microrheology: Structural evolution under static and dynamic conditions by simultaneously analysis of confocal microscopy and diffusing wave spectroscopy

    NARCIS (Netherlands)

    Nicolas, Y.; Paques, M.; Knaebel, A.; Steyer, A.; Munch, J.P.; Blijdenstein, T.B.J.; Aken, van G.A.

    2003-01-01

    An oscillatory shear configuration was developed to improve understanding of structural evolution during deformation. It combines an inverted confocal scanning laser microscope (CSLM) and a special sample holder that can apply to the sample specific deformation: oscillatory shear or steady strain. I

  5. An analysis of the structure and evolution of the scientific collaboration network of computer intelligence in games

    Science.gov (United States)

    Lara-Cabrera, R.; Cotta, C.; Fernández-Leiva, A. J.

    2014-02-01

    Games constitute a research domain that is attracting the interest of scientists from numerous disciplines. This is particularly true from the perspective of computational intelligence. In order to examine the growing importance of this area in the gaming domain, we present an analysis of the scientific collaboration network of researchers working on computational intelligence in games (CIG). This network has been constructed from bibliographical data obtained from the Digital Bibliography & Library Project (DBLP). We have analyzed from a temporal perspective several properties of the CIG network at the macroscopic, mesoscopic and microscopic levels, studying the large-scale structure, the growth mechanics, and collaboration patterns among other features. Overall, computational intelligence in games exhibits similarities with other collaboration networks such as for example a log-normal degree distribution and sub-linear preferential attachment for new authors. It also has distinctive features, e.g. the number of papers co-authored is exponentially distributed, the internal preferential attachment (new collaborations among existing authors) is linear, and fidelity rates (measured as the relative preference for publishing with previous collaborators) grow super-linearly. The macroscopic and mesoscopic evolution of the network indicates the field is very active and vibrant, but it is still at an early developmental stage. We have also analyzed communities and central nodes and how these are reflected in research topics, thus identifying active research subareas.

  6. Structural evolution of the VMS-hosting Kristineberg area, Sweden – constraints from structural analysis and 3-D-modelling

    Directory of Open Access Journals (Sweden)

    J. Hübert

    2012-10-01

    Full Text Available Structural mapping and 3-D-modelling with constraints from magnetotelluric (MT and reflection seismic investigations have been used to provide a geological synthesis of the geometrically complex Kristineberg area in the western part of the Palaeoproterozoic Skellefte district. The results indicate that, like the south-eastern parts of the Skellefte district, the area was subjected to SSE-NNW transpressional deformation at around 1.87 Ga. The contrasting structural geometries between the Kristineberg and the central Skellefte district areas may be attributed to the termination and splaying of a major ESE-WNW-striking high-strain zone into several branches in the northern part of the Kristineberg area. The transpressional structural signature was preferentially developed within the southern of the two antiformal structures of the area, "the Southern antiform", which exposes the deepest cut through the crust and hosts all the economic volcanogenic massive sulphides (VMS deposits of the area. Partitioning of the SSE-NNW transpression into N–S and E–W components led to formation of a characteristic "flat-steep-flat" geometry defining a highly non-cylindrical hinge of for the Southern antiform. Recognition of the transpressional structural signatures including the "flat-steep-flat" geometry and the distinct pattern of sub-horizontal E–W trending to moderately SW-plunging mineral lineations in the deeper crustal parts of the Kristineberg area is of significance for VMS exploration in both near mine and regional scales. The 3-D-model illustrating the outcomes of this study is available as a 3-D-PDF document through the publication website.

  7. 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.

  8. Microrheology: Structural evolution under static and dynamic conditions by simultaneous analysis of confocal microscopy and diffusing wave spectroscopy

    Science.gov (United States)

    Nicolas, Yves; Paques, Marcel; Knaebel, Alexandra; Steyer, Alain; Munch, Jean-Pierre; Blijdenstein, Theo B. J.; van Aken, George A.

    2003-08-01

    An oscillatory shear configuration was developed to improve understanding of structural evolution during deformation. It combines an inverted confocal scanning laser microscope (CSLM) and a special sample holder that can apply to the sample specific deformation: oscillatory shear or steady strain. In this configuration, a zero-velocity plane is created in the sample by moving two plates in opposite directions, thereby providing stable observation conditions of the structural behavior under deformation. The configuration also includes diffusion wave spectroscopy (DWS) to monitor the network properties via particle mobility under static and dynamic conditions. CSLM and DWS can be performed simultaneously and three-dimensional images can be obtained under static conditions. This configuration is mainly used to study mechanistic phenomena like particle interaction, aggregation, gelation and network disintegration, interactions at interfaces under static and dynamic conditions in semisolid food materials (desserts, dressings, sauces, dairy products) and in nonfood materials (mineral emulsions, etc.). Preliminary data obtained with this new oscillatory shear configuration are described that demonstrate their capabilities and the potential contribution to other areas of application also.

  9. Phylogeny and evolution of RNA structure.

    Science.gov (United States)

    Gesell, Tanja; Schuster, Peter

    2014-01-01

    Darwin's conviction that all living beings on Earth are related and the graph of relatedness is tree-shaped has been essentially confirmed by phylogenetic reconstruction first from morphology and later from data obtained by molecular sequencing. Limitations of the phylogenetic tree concept were recognized as more and more sequence information became available. The other path-breaking idea of Darwin, natural selection of fitter variants in populations, is cast into simple mathematical form and extended to mutation-selection dynamics. In this form the theory is directly applicable to RNA evolution in vitro and to virus evolution. Phylogeny and population dynamics of RNA provide complementary insights into evolution and the interplay between the two concepts will be pursued throughout this chapter. The two strategies for understanding evolution are ultimately related through the central paradigm of structural biology: sequence ⇒ structure ⇒ function. We elaborate on the state of the art in modeling both phylogeny and evolution of RNA driven by reproduction and mutation. Thereby the focus will be laid on models for phylogenetic sequence evolution as well as evolution and design of RNA structures with selected examples and notes on simulation methods. In the perspectives an attempt is made to combine molecular structure, population dynamics, and phylogeny in modeling evolution.

  10. 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.

  11. Industrial Structure Evolution and Economic Growth in Dingxi City Based on Shift-Share Method and Location Quotient Analysis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    According to the statistical data in the years 2004-2008, both Shift-Share Analysis and Location Quotient Analysis are used to compare the economic development status of counties (districts) in Dingxi City in the years 2004 and 2008. Advantages and disadvantages of industrial structure and competitiveness are analyzed, as well as the impacts of existing industrial structure on economic growth. Development direction and development focus of primary, secondary and tertiary industries are found out. Countermeasures for accelerating the economic development of counties (districts) in Dingxi City are put forward, such as increasing the inputs in characteristic agriculture, promoting the development of primary industry, speeding up the construction of large and medium industrial enterprises, enhancing the development of secondary industry, strengthening comprehensive environmental improvement in tourist area, and actively developing tertiary industry.

  12. Effectiveness of Land Use Structure Evolution to Industrial Structure Transformation

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Scarcity of land resources and transformation of industrial structure is a pair of contradictory elements.We derive the characteristics of land use structure and industrial structure transformation in Xining City using Transformation Coefficient(TC):first,in the period 1999-2000,the land use structure coefficient(θ1) declined by 79.55%,but the overall evolution trend is gentle;second,the transformation coefficient of industrial structure(θ2) tended to decline ceaselessly on the whole,a decrease of 36.09%(overall,the transformation coefficient of industrial structure is slightly greater than the land use structure coefficient);third,the inter-annual variation of the two experienced ups and downs(in the period 1999-2007,the inter-annual variation was great and in the period 2008-2010,the inter-annual variation tended to be gentle).On the basis of autocorrelation and co-integration model,we draw the following conclusions through analysis:first,the land use structure in Xining City plays a role in promoting industrial structure transformation;second,there is a long-term equilibrium relationship between the two.Finally,relevant policy recommendations are put forward for the industrial development in Xining City.

  13. 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.

  14. The Evolution and Structure of Early-type Field Galaxies: A Combined Statistical Analysis of Gravitational Lenses

    CERN Document Server

    Rusin, D

    2004-01-01

    We introduce a framework for simultaneously investigating the structure and luminosity evolution of early-type gravitational lens galaxies. The method is based on the fundamental plane, which we interpret using the aperture mass-radius relations derived from lensed image geometries. We apply this method to our previous sample of 22 lens galaxies with measured redshifts and excellent photometry. Modeling the population with a single mass profile and evolutionary history, we find that early-type galaxies are nearly isothermal (logarithmic density slope n = 2.06 +/- 0.17, 68% C.L.), and that their stars evolve at a rate of dlog(M/L)_B/dz = -0.50 +/- 0.19 (68% C.L.) in the rest frame B band. For a Salpeter IMF and a concordance cosmology, this implies a mean star formation redshift of > 1.5 at 95% confidence. While this model can neatly describe the mean properties of early-type galaxies, it is clear that the scatter of the lens sample is too large to be explained by observational uncertainties alone. We therefo...

  15. 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...

  16. 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.

  17. 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

  18. 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

  19. Structural Architecture and Evolution of Kumkuli Basin, North Tibet

    Institute of Scientific and Technical Information of China (English)

    He Bizhu; Xu Zhiqin; Jiao Cunli; Cui Junwen; Wang Shenglang; Wang Gonghuai; Li Zhaoyang; Qiu Zhuli

    2009-01-01

    Utilizing the new data of gravity, magnetic, and magnetotelluric survey, we analyzed the characteristics of the three geophysical attribute (gravity, magnetic, and resistivity) interfaces and the deep architecture and structure of Kumkuli basin. The research results can provide basic data for early basin structural study. From coupled basin and mountain system, analysis of the structure, and evolution of Knmknli basin, we found that there was zoning from north to south and from west to east. Kumkuli basin has three structural architecture layers including metamorphic crystallization basement, fold basement and sedimentary cover. Knmkuli basin can be divided into three structural units, two depressions, and one uplift. Structural evolution of the Kumkuli basin can be divided into five evolution stages, including Kumkuli microcontinent formed in Sinian-Ordovician, suture around Kumkuli basin formed in Eopaleozoic, retroarc foreland basin formed in Neopaleozoic, rejuvenated foreland hasin developed in Mesozoic, and strike slip and compression basin developed in Cenozoic.

  20. 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.

  1. 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.

  2. 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.

  3. Evolution of cooperation in spatially structured populations

    Science.gov (United States)

    Brauchli; Killingback; Doebeli

    1999-10-21

    Using a spatial lattice model of the Iterated Prisoner's Dilemma we studied the evolution of cooperation within the strategy space of all stochastic strategies with a memory of one round. Comparing the spatial model with a randomly mixed model showed that (1) there is more cooperative behaviour in a spatially structured population, (2) PAVLOV and generous variants of it are very successful strategies in the spatial context and (3) in spatially structured populations evolution is much less chaotic than in unstructured populations. In spatially structured populations, generous variants of PAVLOV are found to be very successful strategies in playing the Iterated Prisoner's Dilemma. The main weakness of PAVLOV is that it is exploitable by defective strategies. In a spatial context this disadvantage is much less important than the good error correction of PAVLOV, and especially of generous PAVLOV, because in a spatially structured population successful strategies always build clusters. Copyright 1999 Academic Press.

  4. Evolution of the rheological structure of Mars

    Science.gov (United States)

    Azuma, Shintaro; Katayama, Ikuo

    2017-01-01

    The evolution of Mars has been greatly influenced by temporal changes in its rheological structure, which may explain the difference in tectonics between Mars and Earth. Some previous studies have shown the rheological structures of Mars calculated from the flow law of rocks and the predicted thermal structure. However, the Peierls mechanism, which is the dominant deformation mechanism at relatively low temperature, and the evolution of water reservoirs on Mars were not considered in such studies. In this paper, we apply the Peierls mechanism to refine the rheological structure of Mars to show a new history of the planet that considers the most recent reports on its evolution of water reservoirs. Considering the Peierls creep and the evolution of water reservoirs, we attempt to explain why the tectonics of Mars is inactive compared with that of Earth. On early Mars, the lithospheric thickness inferred from the brittle-ductile transition was small, and the lithospheric strength was low ( 200-300 MPa) under wet conditions at 4 Gya. This suggests that plate boundaries could have developed on the early "wet" Mars, which is a prerequisite for the operation of plate tectonics. Our results also imply that the lithospheric strength had significantly increased in the Noachian owing to water loss. Therefore, plate tectonics may have ceased or could no longer be initiated on Mars. At the least, the tectonic style of Mars would have dramatically changed during the Noachian.[Figure not available: see fulltext.

  5. 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.

  6. NUMERICAL SOLUTION OF SHORELINE EVOLUTION NEAR COASTAL STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    Cai Ze-wei; Song Xiao-gang; Ye Chun-yang

    2003-01-01

    Numerical analysis was made for shoreline evolution in the vicinity of coastal structures, including spur dike, detached breakwaters. The nonlinear partial differential equation was derived, and numerical solutions were obtained by the finite difference method. The numerical results show good agreement with previous analytical results.

  7. The nonsinglet structure function evolution by Laplace method

    Energy Technology Data Exchange (ETDEWEB)

    Boroun, G. R., E-mail: grboroun@gmail.com, E-mail: boroun@razi.ac.ir; Zarrin, S. [Razi University, Physics Department (Iran, Islamic Republic of)

    2015-12-15

    We derive a general scheme for the evolution of the nonsinglet structure function at the leadingorder (LO) and next-to-leading-order (NLO) by using the Laplace-transform technique. Results for the nonsinglet structure function are compared with MSTW2008, GRV, and CKMT parameterizations and also EMC experimental data in the LO and NLO analysis. The results are in good agreement with the experimental data and other parameterizations in the low- and large-x regions.

  8. Giant Planet Formation, Evolution, and Internal Structure

    CERN Document Server

    Helled, Ravit; Podolak, Morris; Boley, Aaron; Meru, Farzana; Nayakshin, Sergei; Fortney, Jonathan J; Mayer, Lucio; Alibert, Yann; Boss, Alan P

    2013-01-01

    The large number of detected giant exoplanets offers the opportunity to improve our understanding of the formation mechanism, evolution, and interior structure of gas giant planets. The two main models for giant planet formation are core accretion and disk instability. There are substantial differences between these formation models, including formation timescale, favorable formation location, ideal disk properties for planetary formation, early evolution, planetary composition, etc. First, we summarize the two models including their substantial differences, advantages, and disadvantages, and suggest how theoretical models should be connected to available (and future) data. We next summarize current knowledge of the internal structures of solar- and extrasolar- giant planets. Finally, we suggest the next steps to be taken in giant planet exploration.

  9. 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

  10. Molecular evolution of rDNA in early diverging Metazoa: First comparative analysis and phylogenetic application of complete SSU rRNA secondary structures in Porifera

    Directory of Open Access Journals (Sweden)

    Wörheide Gert

    2008-02-01

    Full Text Available Abstract Background The cytoplasmic ribosomal small subunit (SSU, 18S ribosomal RNA (rRNA is the most frequently-used gene for molecular phylogenetic studies. However, information regarding its secondary structure is neglected in most phylogenetic analyses. Incorporation of this information is essential in order to apply specific rRNA evolutionary models to overcome the problem of co-evolution of paired sites, which violates the basic assumption of the independent evolution of sites made by most phylogenetic methods. Information about secondary structure also supports the process of aligning rRNA sequences across taxa. Both aspects have been shown to increase the accuracy of phylogenetic reconstructions within various taxa. Here, we explore SSU rRNA secondary structures from the three extant classes of Phylum Porifera (Grant, 1836, a pivotal, but largely unresolved taxon of early branching Metazoa. This is the first phylogenetic study of poriferan SSU rRNA data to date that includes detailed comparative secondary structure information for all three sponge classes. Results We found base compositional and structural differences in SSU rRNA among Demospongiae, Hexactinellida (glass sponges and Calcarea (calcareous sponges. We showed that analyses of primary rRNA sequences, including secondary structure-specific evolutionary models, in combination with reconstruction of the evolution of unusual structural features, reveal a substantial amount of additional information. Of special note was the finding that the gene tree topologies of marine haplosclerid demosponges, which are inconsistent with the current morphology-based classification, are supported by our reconstructed evolution of secondary structure features. Therefore, these features can provide alternative support for sequence-based topologies and give insights into the evolution of the molecule itself. To encourage and facilitate the application of rRNA models in phylogenetics of early

  11. Heme oxygenase: evolution, structure, and mechanism.

    Science.gov (United States)

    Wilks, Angela

    2002-08-01

    Heme oxygenase has evolved to carry out the oxidative cleavage of heme, a reaction essential in physiological processes as diverse as iron reutilization and cellular signaling in mammals, synthesis of essential light-harvesting pigments in cyanobacteria and higher plants, and the acquisition of iron by bacterial pathogens. In all of these processes, heme oxygenase has evolved a similar structural and mechanistic scaffold to function within seemingly diverse physiological pathways. The heme oxygenase reaction is catalytically distinct from that of other hemoproteins such as the cytochromes P450, peroxidases, and catalases, but shares a hemoprotein scaffold that has evolved to generate a distinct activated oxygen species. In the following review we discuss the evolution of the structural and functional properties of heme oxygenase in light of the recent crystal structures of the mammalian and bacterial enzymes.

  12. 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.

  13. Structural evolution of ball-milled permalloy

    Energy Technology Data Exchange (ETDEWEB)

    Brzozka, K., E-mail: kbrzozka@poczta.f [Technical University, Department of Physics (Poland); Oleksakova, D.; Kollar, P. [P.J. Safarik University, Department of Condensed Matter Physics, Institute of Physics, Faculty of Science (Slovakia); Szumiata, T.; Gorka, B.; Gawronski, M. [Technical University, Department of Physics (Poland)

    2006-02-15

    Two series of Fe{sub 19.8}Ni{sub 80.2} samples obtained by ball milling and differing in the form of starting material were investigated by Moessbauer spectroscopy. In the case of milled elemental powder, strong structural evolution was stated: both {alpha} and {gamma} phases arise and a small amount of pure iron is present as well. The annealing of as-milled powder at 490{sup o}C causes faster forming of {gamma}-(Ni-Fe) phase. Only slight changes in atomic order were stated in the series of milled polycrystalline ribbon.

  14. 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.

  15. 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.

  16. Phylogenomic and structural analyses of 18 complete plastomes across nearly all families of early-diverging eudicots, including an angiosperm-wide analysis of IR gene content evolution.

    Science.gov (United States)

    Sun, Yanxia; Moore, Michael J; Zhang, Shoujun; Soltis, Pamela S; Soltis, Douglas E; Zhao, Tingting; Meng, Aiping; Li, Xiaodong; Li, Jianqiang; Wang, Hengchang

    2016-03-01

    The grade of early-diverging eudicots includes five major lineages: Ranunculales, Trochodendrales, Buxales, Proteales and Sabiaceae. To examine the evolution of plastome structure in early-diverging eudicots, we determined the complete plastome sequences of eight previously unsequenced early-diverging eudicot taxa, Pachysandra terminalis (Buxaceae), Meliosma aff. cuneifolia (Sabiaceae), Sabia yunnanensis (Sabiaceae), Epimedium sagittatum (Berberidaceae), Euptelea pleiosperma (Eupteleaceae), Akebia trifoliata (Lardizabalaceae), Stephania japonica (Menispermaceae) and Papaver somniferum (Papaveraceae), and compared them to previously published plastomes of the early-diverging eudicots Buxus, Tetracentron, Trochodendron, Nelumbo, Platanus, Nandina, Megaleranthis, Ranunculus, Mahonia and Macadamia. All of the newly sequenced plastomes share the same 79 protein-coding genes, 4 rRNA genes, and 30 tRNA genes, except for that of Epimedium, in which infA is pseudogenized and clpP is highly divergent and possibly a pseudogene. The boundaries of the plastid Inverted Repeat (IR) were found to vary significantly across early-diverging eudicots; IRs ranged from 24.3 to 36.4kb in length and contained from 18 to 33 genes. Based on gene content, the IR was classified into six types, with shifts among types characterized by high levels of homoplasy. Reconstruction of ancestral IR gene content suggested that 18 genes were likely present in the IR region of the ancestor of eudicots. Maximum likelihood phylogenetic analysis of a 79-gene, 97-taxon data set that included all available early-diverging eudicots and representative sampling of remaining angiosperm diversity largely agreed with previous estimates of early-diverging eudicot relationships, but resolved Trochodendrales rather than Buxales as sister to Gunneridae, albeit with relatively weak bootstrap support, conflicting with what has been found for these three clades in most previous analyses. In addition, Proteales was

  17. 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.

  18. Triadic Conceptual Structure of the Maximum Entropy Approach to Evolution

    CERN Document Server

    Herrmann-Pillath, Carsten

    2010-01-01

    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. Following recent contributions to the naturalization of Peircean semiosis, we show that triadic structures involve the conjunction of three different kinds of causality, efficient, formal and final. 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 device...

  19. Structural evolution and metallicity of lead clusters

    Science.gov (United States)

    Götz, Daniel A.; Shayeghi, Armin; Johnston, Roy L.; Schwerdtfeger, Peter; Schäfer, Rolf

    2016-05-01

    The evolution of the metallic state in lead clusters and its structural implications are subject to ongoing discussions. Here we present molecular beam electric deflection studies of neutral PbN (N = 19-25, 31, 36, 54) clusters. Many of them exhibit dipole moments or anomalies of the polarizability indicating a non-metallic state. In order to resolve their structures, the configurational space is searched using the Pool Birmingham Cluster Genetic algorithm based on density functional theory. Spin-orbit effects on the geometries and dipole moments are taken into account by further relaxing them with two-component density functional theory. Geometries and dielectric properties from quantum chemical calculations are then used to simulate beam deflection profiles. Structures are assigned by the comparison of measured and simulated beam profiles. Energy gaps are calculated using time-dependent density functional theory. They are compared to Kubo gaps, which are an indicator of the metallicity in finite particles. Both, experimental and theoretical data suggest that lead clusters are not metallic up to at least 36 atoms.The evolution of the metallic state in lead clusters and its structural implications are subject to ongoing discussions. Here we present molecular beam electric deflection studies of neutral PbN (N = 19-25, 31, 36, 54) clusters. Many of them exhibit dipole moments or anomalies of the polarizability indicating a non-metallic state. In order to resolve their structures, the configurational space is searched using the Pool Birmingham Cluster Genetic algorithm based on density functional theory. Spin-orbit effects on the geometries and dipole moments are taken into account by further relaxing them with two-component density functional theory. Geometries and dielectric properties from quantum chemical calculations are then used to simulate beam deflection profiles. Structures are assigned by the comparison of measured and simulated beam profiles. Energy gaps

  20. Molecular dynamics study of ice structural evolution

    Institute of Scientific and Technical Information of China (English)

    Wang Yan; Dong Shun-Le

    2008-01-01

    Molecular dynamics simulation is employed to study the structural evolution of low density amorphous ice during its compression from one atmosphere to 2.5 GPa. Calculated results show that high density amorphous ice is formed at an intermediate pressure of~1.0GPa; the O-O-O bond angle ranges from 83° to 113°, and the O-H...O bond is bent from 112° to 160°. Very high density amorphous ice is obtained by quenching to 80K and decompressing the ice to ambient pressure from 160 K/1.3 GPa or 160 K/1.7 GPa; and the next-nearest O-O length is found to be 0.310 nm, just 0.035 nm beyond the nearest O-O distance of 0.275 nm.

  1. Structural Evolution of Compressing Amorphous Ice

    Institute of Scientific and Technical Information of China (English)

    WANG Yan; DONG Shun-Le

    2007-01-01

    Molecular dynamics simulation is employed to study structural evolution during compressing low density amorphous ice from one atmosphere to 2.5 GPa.The calculated results show that high density amorphous ice is formed under intermediate pressure of about 1.0 GPa and O-O-O angle ranges from about 83°to 113°and O-H……O is bent from 112°to 160°.The very high density amorphous ice is also formed under the pressure larger than 1.4 GPa and interstitial molecules are found in 0.3-0.4 (A) just beyond the nearest O-O distance.Low angle O-H……O disappears and it is believed that these hydrogen bonds are broken or re-bonded under high pressures.

  2. 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.

  3. The proteome: structure, function and evolution.

    Science.gov (United States)

    Fleming, Keiran; Kelley, Lawrence A; Islam, Suhail A; MacCallum, Robert M; Muller, Arne; Pazos, Florencio; Sternberg, Michael J E

    2006-03-29

    This paper reports two studies to model the inter-relationships between protein sequence, structure and function. First, an automated pipeline to provide a structural annotation of proteomes in the major genomes is described. The results are stored in a database at Imperial College, London (3D-GENOMICS) that can be accessed at www.sbg.bio.ic.ac.uk. Analysis of the assignments to structural superfamilies provides evolutionary insights. 3D-GENOMICS is being integrated with related proteome annotation data at University College London and the European Bioinformatics Institute in a project known as e-protein (http://www.e-protein.org/). The second topic is motivated by the developments in structural genomics projects in which the structure of a protein is determined prior to knowledge of its function. We have developed a new approach PHUNCTIONER that uses the gene ontology (GO) classification to supervise the extraction of the sequence signal responsible for protein function from a structure-based sequence alignment. Using GO we can obtain profiles for a range of specificities described in the ontology. In the region of low sequence similarity (around 15%), our method is more accurate than assignment from the closest structural homologue. The method is also able to identify the specific residues associated with the function of the protein family.

  4. Study on Evolution of Spatial Structure of Pan-Linxia Economic Zone

    OpenAIRE

    Jing Xu

    2014-01-01

    This paper applies spatial correlation method in spatial statistics and GIS technology to analyze special structural form and evolution process of regional economy of Pan-Linxia region. Morphological analysis of spatial structure shows the correlation between economic development level of Linxia City and regional economic development in the minority area of south Gansu has strong complementarities. The evolution of spatial structure shows spatial correlation between the economy in Linxia City...

  5. Community evolution mining and analysis in social network

    Science.gov (United States)

    Liu, Hongtao; Tian, Yuan; Liu, Xueyan; Jian, Jie

    2017-03-01

    With the development of digital and network technology, various social platforms emerge. These social platforms have greatly facilitated access to information, attracting more and more users. They use these social platforms every day to work, study and communicate, so every moment social platforms are generating massive amounts of data. These data can often be modeled as complex networks, making large-scale social network analysis possible. In this paper, the existing evolution classification model of community has been improved based on community evolution relationship over time in dynamic social network, and the Evolution-Tree structure is proposed which can show the whole life cycle of the community more clearly. The comparative test result shows that the improved model can excavate the evolution relationship of the community well.

  6. 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.

  7. Crustal structure of Northern Latium (central Italy) from receiver functions analysis: New evidences of a post-collisional back-arc margin evolution

    Science.gov (United States)

    Buttinelli, Mauro; Chiarabba, Claudio; Anselmi, Mario; Bianchi, Irene; De Rita, Donatella; Quattrocchi, Fedora

    2014-05-01

    The crustal velocity structure in a region of central Apennines of Italy at the hinge between the highly stretched portion of the Monte Argentario promontory and the magmatic province of the Tolfa Domes Complex (Northern Latium) is discussed in this study. S-wave velocities at depth have been constrained by the modeling of P-wave receiver functions (RF) from both temporary and permanent broadband seismic stations. The computer 3D Vs models show a thin crust (19-25 km) made of a shallow and thin sedimentary cover, a very high velocity and anisotropic layer related to a metamorphic basement, and a low Vs anisotropic layer in the middle-lower crust above a shallow Moho discontinuity modeled at about 20 km depth. The volcano-tectonic evolution of this portion of Tyrrhenian back-arc margin has been strongly influenced by its peculiar crustal architecture. The low-Vs layer acted as a shear zone in the middle-lower crust during the Tyrrhenian extension, also helping the development of Plio-Quaternary magmatism. Our findings potentially give new constraints on the evolution of the area and to the general comprehension of back-arc development in collisional regions.

  8. Population structure and evolution of Rhinoviruses.

    Directory of Open Access Journals (Sweden)

    Vaishali P Waman

    Full Text Available Rhinoviruses, formerly known as Human rhinoviruses, are the most common cause of air-borne upper respiratory tract infections in humans. Rhinoviruses belong to the family Picornaviridae and are divided into three species namely, Rhinovirus A, -B and -C, which are antigenically diverse. Genetic recombination is found to be one of the important causes for diversification of Rhinovirus species. Although emerging lineages within Rhinoviruses have been reported, their population structure has not been studied yet. The availability of complete genome sequences facilitates study of population structure, genetic diversity and underlying evolutionary forces, such as mutation, recombination and selection pressure. Analysis of complete genomes of Rhinoviruses using a model-based population genetics approach provided a strong evidence for existence of seven genetically distinct subpopulations. As a result of diversification, Rhinovirus A and -C populations are divided into four and two subpopulations, respectively. Genetically, the Rhinovirus B population was found to be homogeneous. Intra-species recombination was observed to be prominent in Rhinovirus A and -C species. Significant evidence of episodic positive selection was obtained for several sites within coding sequences of structural and non-structural proteins. This corroborates well with known phenotypic properties such as antigenicity of structural proteins. Episodic positive selection appears to be responsible for emergence of new lineages especially in Rhinovirus A. In summary, the Rhinovirus population is an ensemble of seven distinct lineages. In case of Rhinovirus A, intra-species recombination and episodic positive selection contribute to its further diversification. In case of Rhinovirus C, intra- and inter-species recombinations are responsible for observed diversity. Population genetics approach was further useful to analyze phylogenetic tree topologies pertaining to recombinant strains

  9. Population structure and evolution of Rhinoviruses.

    Science.gov (United States)

    Waman, Vaishali P; Kolekar, Pandurang S; Kale, Mohan M; Kulkarni-Kale, Urmila

    2014-01-01

    Rhinoviruses, formerly known as Human rhinoviruses, are the most common cause of air-borne upper respiratory tract infections in humans. Rhinoviruses belong to the family Picornaviridae and are divided into three species namely, Rhinovirus A, -B and -C, which are antigenically diverse. Genetic recombination is found to be one of the important causes for diversification of Rhinovirus species. Although emerging lineages within Rhinoviruses have been reported, their population structure has not been studied yet. The availability of complete genome sequences facilitates study of population structure, genetic diversity and underlying evolutionary forces, such as mutation, recombination and selection pressure. Analysis of complete genomes of Rhinoviruses using a model-based population genetics approach provided a strong evidence for existence of seven genetically distinct subpopulations. As a result of diversification, Rhinovirus A and -C populations are divided into four and two subpopulations, respectively. Genetically, the Rhinovirus B population was found to be homogeneous. Intra-species recombination was observed to be prominent in Rhinovirus A and -C species. Significant evidence of episodic positive selection was obtained for several sites within coding sequences of structural and non-structural proteins. This corroborates well with known phenotypic properties such as antigenicity of structural proteins. Episodic positive selection appears to be responsible for emergence of new lineages especially in Rhinovirus A. In summary, the Rhinovirus population is an ensemble of seven distinct lineages. In case of Rhinovirus A, intra-species recombination and episodic positive selection contribute to its further diversification. In case of Rhinovirus C, intra- and inter-species recombinations are responsible for observed diversity. Population genetics approach was further useful to analyze phylogenetic tree topologies pertaining to recombinant strains, especially when trees

  10. Mathematical Analysis of Genomic Evolution

    Directory of Open Access Journals (Sweden)

    Cedric Green

    2011-01-01

    Full Text Available Changes in nucleotide sequences, or mutations, accumulate from generation to generation in the genomes of all living organisms. The mutations can be advantageous, deleterious, or neutral. The goal of this project is to determine the amount of advantageous mutations it takes to get human (Homo sapiens DNA from the DNA of genetically distinct organisms. We do this by collecting the genomic data of such organisms, and estimating the amount of mutations it takes to transform yeast (Saccharomyces cerevisiae DNA to the DNA of a human. We calculate the typical number of mutations occurring annually through the organism's average life span and the average mutation rate. This allows us to determine the total number of mutations as well as the probability of advantageous mutations. Not surprisingly, this probability proves to be fairly small. A more precise estimate can be determined by accounting for the differences in the chromosomal structure and phenomena like horizontal gene transfer.

  11. 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.

  12. 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......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...... bacteriophage TP901-1 proliferation. Short regions of microhomology in intergenic regions present in several lactococcal bacteriophages and chromosomal fragments of Lactococcus lactis are suggested to be points of exchange of genetic material through homologous recombination. Our results indicate that TP901......-1 may have evolved by homologous recombination between the host chromosome and a mother phage and support the observation that phage remnants as well as prophages located in the Lactococcus chromosome contribute significantly to bacteriophage evolution. Some proteins encoded in the early transcribed...

  13. 基于改进耗散结构理论的地铁隧道塌方演化过程分析%Analysis on collapse evolution process of subway tunnel based on improved dissipative structure theory

    Institute of Scientific and Technical Information of China (English)

    游鹏飞; 牟瑞芳

    2012-01-01

    Since the subway tunnel construction has obvious non-linear characteristics, the collapse evolution process becomes very complicated. At present, most researchers mainly used the method of numerical simulation analysis to study the evolution process of collapse and certain achievements were accomplished. Because of many uncertain factors existing in the process of the tunnel construction, assumptions and simplification of the simulation are often required, which reduces the credibility of numerical simulation results. In order to accurately describe the collapse evolution process, this paper firstly analyzes the evolution of the general rule of subway tunnel collapse, and attempts to explore the method which can describe the collapse evolution process based on the perspective of theoretical analysis. The defects about the traditional dissipative structure theory of thermody-namic are improved in this paper, which can be described as follows: (1) The entropy is a state function which can not be input or output directly and only depend on a certain energy, i.e. collapse "negative entropy energy" is used to describe the formation process of collapse dissipative structure instead of " negative entropy"; (2) Negative entropy energy includes both direct and indirect negative entropy energy, but the traditional thermodynamic theory does not take into account the indirect negative entropy energy. This paper introduces the generalized concept of negative entropy energy, and deduces energy damage evolution equation of collapse. The improved dissipation structure theory is introduced to the research on collapse pregnancy risk mechanism of the subway tunnel construction. This paper established the damage evolution equation of negative entropy energy (ordering energy) and generalized negative entropy energy (generalized ordering energy) , used negative entropy energy to analyze the collapse dissipative structure. The research provided a new way for the analysis of collapse

  14. 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

  15. 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 role

  16. 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...

  17. 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.

  18. Evolution of fast magnetoacoustic pulses in randomly structured coronal plasmas

    CERN Document Server

    Yuan, D; Nakariakov, V M; Li, B; Keppens, R

    2014-01-01

    Magnetohydrodynamic waves interact with structured plasmas and reveal the internal magnetic and thermal structures therein, thereby having seismological applications in the solar atmosphere. We investigate the evolution of fast magnetoacoustic pulses in randomly structured plasmas, in the context of large-scale propagating waves in the solar atmosphere. We perform one dimensional numerical simulations of fast wave pulses propagating perpendicular to a constant magnetic field in a low-$\\beta$ plasma with a random density profile across the field. Both linear and nonlinear regimes are considered. We study how the evolution of the pulse amplitude and width depends on their initial values and the parameters of the random structuring. A randomly structured plasma acts as a dispersive medium for a fast magnetoacoustic pulse, causing amplitude attenuation and broadening of the pulse width. After the passage of the main pulse, secondary propagating and standing fast waves appear in the plasma. Width evolution of both...

  19. Modified structure of graphene oxide by investigation of structure evolution

    Indian Academy of Sciences (India)

    A Nekahi; S P H Marashi; D Haghshenas Fatmesari

    2015-12-01

    The structure of graphite oxide and graphene oxide (GO) has been studied previously using various analyses and computer simulations. Although some oxygen functional groups (OFGs) are accepted as the main functionalities in GO, the structure of GO has remained elusive. In this regard, GO was produced using the modified Hummers method and was investigated using X-ray diffraction pattern, Fourier transform infrared analysis and Boehm titration method. Based on the obtained results, a modified model was proposed for GO based on the model of Lerf-Klinowski. OFGs include highly carboxyl groups and phenols with few epoxides, lactones and ketones agglomerated in some regions due to hydrogen bonding between functional groups. Trapped water molecules were shown between the GO sheets which strongly affected the distribution of OFGs and their aggregation by hydrogen bonding.

  20. 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.

  1. Structure, Evolution and Nucleosynthesis of Primordial Stars

    CERN Document Server

    Siess, L; Lattanzio, J C; Siess, Lionel; Livio, Mario; Lattanzio, John

    2002-01-01

    (abridge version) The evolution of population III stars (Z=0) is followed from the pre-main sequence phase up to the AGB phase for intermediate-mass stars and up to C ignition in more massive stars...We find that, thanks to the development of mixing episodes (carbon injections) at the beginning of the AGB phase, the carbon abundance of the 1, 1.5, 2, 3, 4 and 5Mo models is significantly increased in the envelope. This process then allows low- and intermediate-mass stars to achieve a ``standard'' thermally pulsing AGB phase... In the 7Mo model, the CNO envelope abundance following the second dredge-up is so large that the star does not experience the carbon injection episode and follows a more standard thermally pulsing AGB evolution. Our computations also indicate that, thanks to a small overshooting at the base of the convective envelope, the third dredge-up is already operating in stars with M >~1.5 Mo after a few pulses, and that by the end of our modeling, hot bottom burning is activated in stars more mas...

  2. 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 particular

  3. Evolution of extortion in structured populations

    CERN Document Server

    Szolnoki, Attila

    2014-01-01

    Extortion strategies can dominate any opponent in an iterated prisoner's dilemma game. But if players are able to adopt the strategies performing better, extortion becomes widespread and evolutionary unstable. It may sometimes act as a catalyst for the evolution of cooperation, and it can also emerge in interactions between two populations, yet it is not the evolutionary stable outcome. Here we revisit these results in the realm of spatial games. We find that pairwise imitation and birth-death dynamics return known evolutionary outcomes. Myopic best response strategy updating, on the other hand, reveals new counterintuitive solutions. Defectors and extortioners coarsen spontaneously, which allows cooperators to prevail even at prohibitively high temptations to defect. Here extortion strategies play the role of a Trojan horse. They may emerge among defectors by chance, and once they do, cooperators become viable as well. These results are independent of the interaction topology, and they highlight the importan...

  4. Evol and ProDy for bridging protein sequence evolution and structural dynamics

    OpenAIRE

    Bakan, Ahmet; Dutta, Anindita; Mao, Wenzhi; Liu, Ying; Chennubhotla, Chakra; Lezon, Timothy R.; Bahar, Ivet

    2014-01-01

    Correlations between sequence evolution and structural dynamics are of utmost importance in understanding the molecular mechanisms of function and their evolution. We have integrated Evol, a new package for fast and efficient comparative analysis of evolutionary patterns and conformational dynamics, into ProDy, a computational toolbox designed for inferring protein dynamics from experimental and theoretical data. Using information-theoretic approaches, Evol coanalyzes conservation and coevolu...

  5. Small x nonlinear evolution with impact parameter and the structure function data

    CERN Document Server

    Berger, Jeffrey

    2011-01-01

    Nonlinear evolution at small values of Bjorken x is evaluated numerically using the dipole framework with impact parameter dependence. Confinement effects are modeled by including masses into the evolution. Sensitivity of the predictions due to different prescriptions of the cuts on large dipole sizes is investigated. Running coupling effects are taken into account in this analysis. Finally, a comparison with the inclusive data from HERA on the structure functions F2 and FL is performed.

  6. Structural analysis for diagnosis

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.

    2002-01-01

    Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential tech-nique to obtain redundant information for diagnosis, is reconsidered in this paper. Matching is reformulated as a problem...

  7. Structural analysis for Diagnosis

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Blanke, M.

    2001-01-01

    Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential technique to obtain redundant information for diagnosis, is re-considered in this paper. Matching is re-formulated as a problem...

  8. Structure, dynamics, assembly, and evolution of protein complexes.

    Science.gov (United States)

    Marsh, Joseph A; Teichmann, Sarah A

    2015-01-01

    The assembly of individual proteins into functional complexes is fundamental to nearly all biological processes. In recent decades, many thousands of homomeric and heteromeric protein complex structures have been determined, greatly improving our understanding of the fundamental principles that control symmetric and asymmetric quaternary structure organization. Furthermore, our conception of protein complexes has moved beyond static representations to include dynamic aspects of quaternary structure, including conformational changes upon binding, multistep ordered assembly pathways, and structural fluctuations occurring within fully assembled complexes. Finally, major advances have been made in our understanding of protein complex evolution, both in reconstructing evolutionary histories of specific complexes and in elucidating general mechanisms that explain how quaternary structure tends to evolve. The evolution of quaternary structure occurs via changes in self-assembly state or through the gain or loss of protein subunits, and these processes can be driven by both adaptive and nonadaptive influences.

  9. 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.

  10. Dynamic structure evolution of time-dependent network

    Science.gov (United States)

    Zhang, Beibei; Zhou, Yadong; Xu, Xiaoyan; Wang, Dai; Guan, Xiaohong

    2016-08-01

    In this paper, we research the long-voided problem of formulating the time-dependent network structure evolution scheme, it focus not only on finding new emerging vertices in evolving communities and new emerging communities over the specified time range but also formulating the complex network structure evolution schematic. Previous approaches basically applied to community detection on time static networks and thus failed to consider the potentially crucial and useful information latently embedded in the dynamic structure evolution process of time-dependent network. To address these problems and to tackle the network non-scalability dilemma, we propose the dynamic hierarchical method for detecting and revealing structure evolution schematic of the time-dependent network. In practice and specificity, we propose an explicit hierarchical network evolution uncovering algorithm framework originated from and widely expanded from time-dependent and dynamic spectral optimization theory. Our method yields preferable results compared with previous approaches on a vast variety of test network data, including both real on-line networks and computer generated complex networks.

  11. Evolution Analysis About Soybean MIR166 Family

    Institute of Scientific and Technical Information of China (English)

    Wang Zhi-hao; Jin Hui-hui; Chen Qing-shan; Zhu Rong-sheng

    2015-01-01

    MicroRNA (miRNA) is a class of important regulating non-coding small molecular RNA. The gma-MIR166 gene family consists of 21 members and their expression patterns diversify widely. It is important to analyze the evolution of gma-MIR166 gene family in order to understand the evolutionary mechanisms of miRNAs in soybean. In this study, we implemented soybean wide genome block analysis, the molecular phylogeny of gma-MIR166 and block analysis of gma-MIR166 family. The results showed that both chromosome big segmental duplications and tandem duplications were main reasons contributed to the expanding of gma-MIR166 gene family. These findings suggested that gma-MIR166 gene family might originate from one or two ancient miRNA genes. The results of research provided a support for evolutionary study of miRNAs in soybean and related species in Fabaceae.

  12. Structural analysis of DAEs

    DEFF Research Database (Denmark)

    Poulsen, Mikael Zebbelin

    2002-01-01

    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......, 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...

  13. Population Structure and Evolution of Rhinoviruses

    OpenAIRE

    2014-01-01

    Rhinoviruses, formerly known as Human rhinoviruses, are the most common cause of air-borne upper respiratory tract infections in humans. Rhinoviruses belong to the family Picornaviridae and are divided into three species namely, Rhinovirus A, -B and -C, which are antigenically diverse. Genetic recombination is found to be one of the important causes for diversification of Rhinovirus species. Although emerging lineages within Rhinoviruses have been reported, their population structure has not ...

  14. Probabilistic Structural Analysis Program

    Science.gov (United States)

    Pai, Shantaram S.; Chamis, Christos C.; Murthy, Pappu L. N.; Stefko, George L.; Riha, David S.; Thacker, Ben H.; Nagpal, Vinod K.; Mital, Subodh K.

    2010-01-01

    NASA/NESSUS 6.2c is a general-purpose, probabilistic analysis program that computes probability of failure and probabilistic sensitivity measures of engineered systems. Because NASA/NESSUS uses highly computationally efficient and accurate analysis techniques, probabilistic solutions can be obtained even for extremely large and complex models. Once the probabilistic response is quantified, the results can be used to support risk-informed decisions regarding reliability for safety-critical and one-of-a-kind systems, as well as for maintaining a level of quality while reducing manufacturing costs for larger-quantity products. NASA/NESSUS has been successfully applied to a diverse range of problems in aerospace, gas turbine engines, biomechanics, pipelines, defense, weaponry, and infrastructure. This program combines state-of-the-art probabilistic algorithms with general-purpose structural analysis and lifting methods to compute the probabilistic response and reliability of engineered structures. Uncertainties in load, material properties, geometry, boundary conditions, and initial conditions can be simulated. The structural analysis methods include non-linear finite-element methods, heat-transfer analysis, polymer/ceramic matrix composite analysis, monolithic (conventional metallic) materials life-prediction methodologies, boundary element methods, and user-written subroutines. Several probabilistic algorithms are available such as the advanced mean value method and the adaptive importance sampling method. NASA/NESSUS 6.2c is structured in a modular format with 15 elements.

  15. EVOLUTION OF FAST MAGNETOACOUSTIC PULSES IN RANDOMLY STRUCTURED CORONAL PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, D.; Li, B. [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai 264209 (China); Pascoe, D. J.; Nakariakov, V. M. [Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Keppens, R., E-mail: Ding.Yuan@wis.kuleuven.be, E-mail: bbl@sdu.edu.cn [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium)

    2015-02-01

    We investigate the evolution of fast magnetoacoustic pulses in randomly structured plasmas, in the context of large-scale propagating waves in the solar atmosphere. We perform one-dimensional numerical simulations of fast wave pulses propagating perpendicular to a constant magnetic field in a low-β plasma with a random density profile across the field. Both linear and nonlinear regimes are considered. We study how the evolution of the pulse amplitude and width depends on their initial values and the parameters of the random structuring. Acting as a dispersive medium, a randomly structured plasma causes amplitude attenuation and width broadening of the fast wave pulses. After the passage of the main pulse, secondary propagating and standing fast waves appear. Width evolution of both linear and nonlinear pulses can be well approximated by linear functions; however, narrow pulses may have zero or negative broadening. This arises because narrow pulses are prone to splitting, while broad pulses usually deviate less from their initial Gaussian shape and form ripple structures on top of the main pulse. Linear pulses decay at an almost constant rate, while nonlinear pulses decay exponentially. A pulse interacts most efficiently with a random medium with a correlation length of about half of the initial pulse width. This detailed model of fast wave pulses propagating in highly structured media substantiates the interpretation of EIT waves as fast magnetoacoustic waves. Evolution of a fast pulse provides us with a novel method to diagnose the sub-resolution filamentation of the solar atmosphere.

  16. STRUCTURAL EVOLUTION IN BIORENEWABLE SOY BASED POLYURETHANES

    Institute of Scientific and Technical Information of China (English)

    Deepa Puthanparambil; Casey Kimball; Shaw Ling Hsu; Zhiyong Ren

    2009-01-01

    Spectroscopic studies have revealed that the amount of polyureas formed and the kinetics of their formation in soy based polyurethane systems are considerably different from traditional systems employing ethylene oxide-propylene oxide (EO-PO) based polyols. The aggregation of polyureas was characterized by the hydrogen bonds formed utilizing FTIR spectroscopy. This study offered the opportunity to assign the previously undefined infrared features. The structural transformation is reflected in the segmental relaxation kinetics characterized by spin-spin diffusion most conveniently measured using low field NMR. The reaction kinetics and the products formed are directly related to the hydrophobic nature of the soy based polyols and its inability to disperse water.

  17. Analysis of planetary evolution with emphasis on differentiation and dynamics

    Science.gov (United States)

    Kaula, William M.; Newman, William I.

    1987-01-01

    In order to address the early stages of nebula evolution, a three-dimensional collapse code which includes not only hydrodynamics and radiative transfer, but also the effects of ionization and, possibly, magnetic fields is being addressed. As part of the examination of solar system evolution, an N-body code was developed which describes the latter stages of planet formation from the accretion of planetesimals. To test the code for accuracy and run-time efficiency, and to develop a stronger theoretical foundation, problems were studied in orbital dynamics. A regional analysis of the correlation in the gravity and topography fields of Venus was performed in order to determine the small and intermediate scale subsurface structure.

  18. Structural Evolution of Interstellar Polycyclic Aromatic Hydrocarbons

    Science.gov (United States)

    Hammonds, Mark; Candian, Alessandra; Mori, Tamami; Usui, Fumihiko; Onaka, Takashi

    2015-08-01

    Polycyclic Aromatic Hydrocarbons (PAHs) are an important reservoir for molecular carbon in the interstellar medium (ISM), and investigations into their chemistry and behaviour may be important to the understanding of how carbon is processed from simple forms into complex prebiotic molecules such as those detected in chondritic meteorites. In this study, infrared astronomical data from AKARI and other observatories are used together with laboratory and theoretical data to study variations in the structure of emitting PAHs in interstellar environments using spectroscopic decomposition techniques and bands arising from carbon-hydrogen bond vibrations at wavelengths from 3 - 14 microns. Results and inferences are discussed in terms of the processing of large carbonaceous molecules in astrophysical environments.

  19. Rehabilitation Counselor Education Accreditation: History, Structure, and Evolution

    Science.gov (United States)

    Shaw, Linda R.; Kuehn, Marvin D.

    2009-01-01

    This review examines some of the critical factors that influenced the evolution of rehabilitation counselor education accreditation. The article discusses the history and structure of the accreditation process and the activities that have occurred to maintain the relevancy and viability of the process. Major issues that the Council on…

  20. Stable Solution of Nonlinear Age-structuredForest Evolution System

    Institute of Scientific and Technical Information of China (English)

    WANGDing-jiang; ZHAOTing-fang

    2004-01-01

    This paper studies the dynamical behavior of a class of total area dependent nonlinear age-structured forest evolution model. We give the problem of equal value for the forest system, and discuss the stable solution of system. We obtained the necessary and sufficient conditions for there exists the stable solution.

  1. Prolongation Structure of Semi-discrete Nonlinear Evolution Equations

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on noncommutative differential calculus, we present a theory of prolongation structure for semi-discrete nonlinear evolution equations. As an illustrative example, a semi-discrete model of the nonlinear Schr(o)dinger equation is discussed in terms of this theory and the corresponding Lax pairs are also given.

  2. 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.

  3. Evolution and physics in comparative protein structure modeling.

    Science.gov (United States)

    Fiser, András; Feig, Michael; Brooks, Charles L; Sali, Andrej

    2002-06-01

    From a physical perspective, the native structure of a protein is a consequence of physical forces acting on the protein and solvent atoms during the folding process. From a biological perspective, the native structure of proteins is a result of evolution over millions of years. Correspondingly, there are two types of protein structure prediction methods, de novo prediction and comparative modeling. We review comparative protein structure modeling and discuss the incorporation of physical considerations into the modeling process. A good starting point for achieving this aim is provided by comparative modeling by satisfaction of spatial restraints. Incorporation of physical considerations is illustrated by an inclusion of solvation effects into the modeling of loops.

  4. The structure and evolution of plankton communities

    Science.gov (United States)

    Longhurst, Alan R.

    New understanding of the circulation of ancient oceans is not yet matched by progress in our understanding of their pelagic ecology, though it was the planktonic ecosystems that generated our offshore oil and gas reserves. Can we assume that present-day models of ecosystem function are also valid for ancient seas? This question is addressed by a study of over 4000 plankton samples to derive a comprehensive, global description of zooplankton community structure in modern oceans: this shows that copepods form only 50% of the biomass of all plankton, ranging from 70% in polar to 35% in tropical seas. Comparable figures are derived from 14 other taxonomic categories of zooplankton. For trophic groupings, the data indicate globally: geletinous predators - 14%; gelatinous herbivores - 4%; raptorial predators - 33%; macrofiltering herbivores - 20%; macrofiltering omnivores - 25%; and detritivores - 3%. A simple, idealized model for the modern pelagic ecosystem is derived from these percentages which indicates that metazooplankton are not the most important consumers of pico- and nano-plankton production which itself probably constitutes 90% of primary production in warm oceans. This model is then compared with candidate life-forms available in Palaeozoic and Mesozoic oceans to determine to what extent it is also valid for ancient ecosystems: it is concluded that it is probably unnecessary to postulate models fundamentally differing from it in order to accommodate the life-forms, both protozoic and metazoic, known to have populated ancient seas. Remarkably few life-forms have existed which cannot be paralleled in the modern ocean, which contains remarkably few life-forms which cannot be paralleled in the Palaeozoic ocean. As a first assumption, then, it is reasonable to assume that energy pathways were similar in ancient oceans to those we study today.

  5. 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.

  6. Formation and Evolution of Structure in Loop Cosmology

    CERN Document Server

    Bojowald, M; Kagan, M; Singh, P; Skirzewski, A; Bojowald, Martin; Hernandez, Hector; Kagan, Mikhail; Singh, Parampreet; Skirzewski, Aureliano

    2006-01-01

    Inhomogeneous cosmological perturbation equations are derived in loop quantum gravity, taking into account corrections in particular in gravitational parts. This provides a framework for calculating the evolution of modes in structure formation scenarios related to inflationary or bouncing models. Applications here are corrections to the Newton potential and to the evolution of large scale modes which imply non-conservation of curvature perturbations possibly noticeable in a running spectral index. These effects are sensitive to quantization procedures and test the characteristic behavior of correction terms derived from quantum gravity.

  7. 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.

  8. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chiar, J. E.; Ricca, A. [SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Tielens, A. G. G. M. [Leiden Observatory, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Adamson, A. J., E-mail: jchiar@seti.org, E-mail: Alessandra.Ricca@1.nasa.gov, E-mail: tielens@strw.leidenuniv.nl, E-mail: aadamson@gemini.edu [Gemini Observatory, Northern Operations Center, 670 North A' ohoku Place, Hilo, HI 96729 (United States)

    2013-06-10

    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 {mu}m) and aliphatic (3.4 {mu}m) hydrocarbon absorption features in the diffuse ISM along the line of sight toward the Galactic center Quintuplet Cluster. Observationally, sp {sup 2} bonds can be measured in astronomical spectra using the 6.2 {mu}m CC aromatic stretch feature, whereas the 3.4 {mu}m aliphatic feature can be used to quantify the fraction of sp {sup 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 {sup 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.

  10. Structural evolution of zirconium carbide under ion irradiation

    Science.gov (United States)

    Gosset, D.; Dollé, M.; Simeone, D.; Baldinozzi, G.; Thomé, L.

    2008-02-01

    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 11 to 5 × 10 15 cm -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 (high micro-strains appear together with small faulted dislocation loops. At the highest fluence (>10 14 cm -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 14 ions/cm 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.

  11. The Liaonan Metamorphic Core Complex: Constitution, Structure and Evolution

    Institute of Scientific and Technical Information of China (English)

    LIU Junlai; GUAN Huimei; JI Mo; CAO Shuyun; HU Ling

    2006-01-01

    The Liaonan metamorphic core complex (mcc) has a three-layer structure and is constituted by five parts, i.e. a detachment fault zone, an allochthonous upper plate and an supradetachment basin above the fault zone, and highly metamorphosed rocks and intrusive rocks in the lower plate. The allochthonous upper plate is mainly of Neoproterozoic and Paleozoic rocks weakly deformed and metamorphosed in pre-Indosinan stage. Above these rocks is a small-scale supradetachment basin of Cretaceous sedimentary and volcanic rocks. The lower plate is dominated by Archean TTG gneisses with minor amount of supracrustal rocks. The Archean rocks are intruded by late Mesozoic synkinematic monzogranitic and granitic plutons. Different types of fault rocks, providing clues to the evolution of the detachment fault zone, are well-preserved in the fault zone, e.g. mylonitic gneiss,mylonites, brecciated mylonites, microbreccias and pseudotachylites. Lineations in lower plate granitic intrusions have consistent orientation that indicate uniform top-to-NW shearing along the main detachment fault zone. This also provides evidence for the synkinematic characteristics of the granitic plutons in the lower plate. Structural analysis of the different parts in the mcc and isotopic dating of plutonic rocks from the lower plate and mylonitic rocks from detachment fault zone suggest that exhumation of the mcc started with regional crustal extension due to crustal block rotation and tangential shearing. The extension triggered magma formation, upwelling and emplacement. This event ended with appearance of pseudotachylite and fault gauges formed at the uppermost crustal level.U-Pb dating of single zircon grains from granitic rocks in the lower plate gives an age of 130±5 Ma, and biotite grains from the main detachment fault zone have 40Ar-39Ar ages of 108-119 Ma. Several aspects may provide constraints for the exhumation of the Liaonan mcc. These include regional extensional setting, cover

  12. Structure and Evolution of Hot Gas in 30 Dor

    CERN Document Server

    Wang, Q D

    1999-01-01

    We have investigated the structure and evolution of hot gas in the 30 Dor nebula, based on recent X-ray observations. Our deep ROSAT HRI image shows that diffuse X-ray emission arises in blister-shaped regions outlined by loops of HII gas. X-ray spectroscopic data from ASCA confirm the thermal nature of the emission and indicate that hot gas temperature decreases from the core to the halo of the nebula. The structure of the nebula can be understood as outflows of hot and HII gases from the parent giant molecular cloud of the central OB association. The dynamic mixing between the two gas phases is likely responsible for the mass loading to the hot gas, as required to explain the observed thermal structure and X-ray luminosity of the nebula. Such processes should also be important in the formation of similar giant HII regions and in their subsequent evolution into supergiant bubbles or galactic chimneys.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Quanlong [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Bai, Qingshun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Chen, Jiaxuan, E-mail: wangquanlong0@hit.edu.cn [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Sun, Yazhou [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Guo, Yongbo [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Liang, Yingchun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-07-30

    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.

  14. Structural dynamics analysis

    Science.gov (United States)

    Housner, J. M.; Anderson, M.; Belvin, W.; Horner, G.

    1985-01-01

    Dynamic analysis of large space antenna systems must treat the deployment as well as vibration and control of the deployed antenna. Candidate computer programs for deployment dynamics, and issues and needs for future program developments are reviewed. Some results for mast and hoop deployment are also presented. Modeling of complex antenna geometry with conventional finite element methods and with repetitive exact elements is considered. Analytical comparisons with experimental results for a 15 meter hoop/column antenna revealed the importance of accurate structural properties including nonlinear joints. Slackening of cables in this antenna is also a consideration. The technology of designing actively damped structures through analytical optimization is discussed and results are presented.

  15. Voronoi Structural Evolution of Bulk Silicon upon Melting

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-Liang; ZHANG Xin-Yu; WANG Lin-Min; QI Li; ZHANG Su-Hong; ZHU Yan; LIU Ri-Ping

    2011-01-01

    @@ The Voronoi structural evolution of silicon upon melting is investigated using a molecular dynamics simulation.At temperatures below the melting point, the solid state system is identified to have a four-fold coordination structure .As the temperature increases, the five-fold coordination and six-fold coordination structures and are observed.This is explained in terms of increasing atomic displacement due to thermal motion and the trapping of the moving atoms by others.At temperatures above the melting point, nearly ali of the four-fold coordination structures grows into multiple-fold coordination ones.%The Voronoi structural evolution of silicon upon melting is investigated using a molecular dynamics simulation. At temperatures below the melting point, the solid state system is identified to have a four-told coordination structure (4,0,0,0). As the temperature increases, the five-fold coordination (2,3,0,0) and six-fold coordination structures (2,2,2,0) and (0,6,0,0) are observed. This is explained in terms of increasing atomic displacement due to thermal motion and the trapping of the moving atoms by others. At temperatures above the melting point, nearly all of the four-fold coordination structures grows into multiple-fold coordination ones.

  16. Simulated evolution of the dark matter large-scale structure

    CERN Document Server

    Demiański, M; Pilipenko, S; Gottlöber, S

    2011-01-01

    We analyze evolution of the basic properties of simulated large scale structure elements formed by dark matter (DM LSS) and confront it with the observed evolution of the Lyman-$\\alpha$ forest. In three high resolution simulations we selected samples of compact DM clouds of moderate overdensity. Clouds are selected at redshifts $0\\leq z\\leq 3$ with the Minimal Spanning Tree (MST) technique. The main properties of so selected clouds are analyzed in 3D space and with the core sampling approach, what allows us to compare estimates of the DM LSS evolution obtained with two different techniques and to clarify some important aspects of the LSS evolution. In both cases we find that regular redshift variations of the mean characteristics of the DM LSS are accompanied only by small variations of their PDFs, what indicates the self similar character of the DM LSS evolution. The high degree of relaxation of DM particles compressed within the LSS is found along the shortest principal axis of clouds. We see that the inter...

  17. Evolution in vitro: analysis of a lineage of ribozymes

    Science.gov (United States)

    Lehman, N.; Joyce, G. F.

    1993-01-01

    Background: Catalytic RNAs, or ribozymes, possessing both a genotype and a phenotype, are ideal molecules for evolution experiments in vitro. A large, heterogeneous pool of RNAs can be subjected to multiple rounds of selection, amplification and mutation, leading to the development of variants that have some desired phenotype. Such experiments allow the investigator to correlate specific genetic changes with quantifiable alterations of the catalytic properties of the RNA. In addition, patterns of evolutionary change can be discerned through a detailed examination of the genotypic composition of the evolving RNA population. Results: Beginning with a pool of 10(13) variants of the Tetrahymena ribozyme, we carried out in vitro evolution experiments that led to the generation of ribozymes with the ability to cleave an RNA substrate in the presence of Ca2+ ions, an activity that does not exist for the wild-type molecule. Over the course of 12 generations, a seven-error variant emerged that has substantial Ca(2+)-dependent RNA-cleavage activity. Advantageous mutations increased in frequency in the population according to three distinct dynamics--logarithmic, linear and transient. Through a comparative analysis of 31 individual variants, we infer how certain mutations influence the catalytic properties of the ribozyme. Conclusions: In vitro evolution experiments make it possible to elucidate important aspects of both evolutionary biology and structural biochemistry on a reasonable short time scale.

  18. Protoplanetary Disk Structure With Grain Evolution: the ANDES Model

    CERN Document Server

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

    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 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 to 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 partl...

  19. Fault Wear and Friction Evolution: Experimental Analysis

    Science.gov (United States)

    Boneh, Y.; Chang, J. C.; Lockner, D. A.; Reches, Z.

    2011-12-01

    Wear is an inevitable product of frictional sliding of brittle rocks as evidenced by the ubiquitous occurrence of fault gouge and slickenside striations. We present here experimental observations designed to demonstrate the relationship between wear and friction and their governing mechanisms. The experiments were conducted with a rotary shear apparatus on solid, ring-shaped rock samples that slipped for displacements up to tens of meters. Stresses, wear and temperature were continuously monitored. We analyzed 86 experiments of Kasota dolomite, Sierra White granite, Pennsylvania quartzite, Karoo gabbro, and Tennessee sandstone at slip velocities ranging from 0.002 to 0.97 m/s, and normal stress from 0.25 to 6.9 MPa. We conducted two types of runs: short slip experiments (slip distance mechanisms; and long slip experiments (slip distance > 3 m) designed to achieve mature wear conditions and to observe the evolution of wear and friction as the fault surfaces evolved. The experiments reveal three wear stages: initial, running-in, and steady-state. The initial stage is characterized by (1) discrete damage striations, the length of which is comparable to total slip , and local pits or plow features; (2) timing and magnitude of fault-normal dilation corresponds to transient changes of normal and shear stresses; and (3) surface roughness increasing with the applied normal stress. We interpret these observations as wear mechanisms of (a) plowing into the fresh rock surfaces; (b) asperity breakage; and (c) asperity climb. The running-in stage is characterized by (1) intense wear-rate over a critical wear distance of Rd = 0.3-2 m; (2) drop of friction coefficient over a weakening distance of Dc = 0.2-4 m; (3) Rd and Dc display positive, quasi-linear relation with each other. We interpret these observations as indicating the organizing of newly-created wear particles into a 'three-body' structure that acts to lubricate the fault (Reches & Lockner, 2010). The steady

  20. Secondary Privatisation: The Evolution of Ownership Structures of Privatised Enterprises

    OpenAIRE

    Barbara Blaszczyk; Richard Woodward

    2001-01-01

    This summary was prepared and edited by Barbara Blaszczyk and Richard Woodward of CASE - the Center for Social and Economic Research. In the project whose results are presented here, our team investigated the phenomenon of "secondary privatisation" (that is, the post-privatisation evolution of the ownership structures established as the result of initial privatisation) in three transition economies (the Czech Republic, Poland and Slovenia) in the years 1995-1999. Our research covered companie...

  1. New insight on the recent tectonic evolution and uplift of the southern Ecuadorian Andes from gravity and structural analysis of the Neogene-Quaternary intramontane basins

    Science.gov (United States)

    Tamay, J.; Galindo-Zaldívar, J.; Ruano, P.; Soto, J.; Lamas, F.; Azañón, J. M.

    2016-10-01

    The sedimentary basins of Loja, Malacatos-Vilcabamba and Catamayo belong to the Neogene-Quaternary synorogenic intramontane basins of South Ecuador. They were formed during uplift of the Andes since Middle-Late Miocene as a result of the Nazca plate subduction beneath the South American continental margin. This E-W compressional tectonic event allowed for the development of NNE-SSW oriented folds and faults, determining the pattern and thickness of sedimentary infill. New gravity measurements in the sedimentary basins indicate negative Bouguer anomalies reaching up to -292 mGal related to thick continental crust and sedimentary infill. 2D gravity models along profiles orthogonal to N-S elongated basins determine their deep structure. Loja Basin is asymmetrical, with a thickness of sedimentary infill reaching more than 1200 m in the eastern part, which coincides with a zone of most intense compressive deformation. The tectonic structures include N-S, NW-SE and NE-SW oriented folds and associated east-facing reverse faults. The presence of liquefaction structures strongly suggests the occurrence of large earthquakes just after the sedimentation. The basin of Malacatos-Vilcabamba has some folds with N-S orientation. However, both Catamayo and Malacatos-Vilcabamba basins are essentially dominated by N-S to NW-SE normal faults, producing a strong asymmetry in the Catamayo Basin area. The initial stages of compression developed folds, reverse faults and the relief uplift determining the high altitude of the Loja Basin. As a consequence of the crustal thickening and in association with the dismantling of the top of the Andes Cordillera, extensional events favored the development of normal faults that mainly affect the basins of Catamayo and Malacatos-Vilcabamba. Gravity research helps to constrain the geometry of the Neogene-Quaternary sedimentary infill, shedding some light on its relationship with tectonic events and geodynamic processes during intramontane basin

  2. The Evolution of Community Structure in a Coauthorship Network

    Directory of Open Access Journals (Sweden)

    William Mcdowell

    2011-12-01

    Full Text Available Mechanisms such as triadic closure and preferential attachment drive the evolution of social networks. Many models use these mechanisms to predict future links, and they generate realistic networks with scale-free degree distributions. These social networks also have community structure, or sets of vertices which are more connected to each other than the rest of the network. To study the evolution of research groups of scientists in a coauthorship network, we use a timeheterarchy representation to extend the mechanisms driving the evolution of the network to the level of this community structure. Specifically, we examine changes in the structure of groups in terms of mechanisms analogous to triadic closure and preferential attachment, and as a result, we find that the network evolves in the same way at the group-level and the individual-level. In addition, we find that interactions at the group-level might affect interactions at the individual-level in that members of a single group are more likely to strengthen their relationships than members of separate groups.

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

    Energy Technology Data Exchange (ETDEWEB)

    Akimkin, V.; Wiebe, D.; Pavlyuchenkov, Ya. [Institute of Astronomy of the RAS, Pyatnitskaya str. 48, Moscow (Russian Federation); Zhukovska, S.; Semenov, D.; Henning, Th. [Max-Planck-Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Vasyunin, A. [Department of Chemistry, The University of Virginia, VA (United States); Birnstiel, T., E-mail: akimkin@inasan.ru, E-mail: dwiebe@inasan.ru, E-mail: pavyar@inasan.ru, E-mail: zhukovska@mpia.de, E-mail: semenov@mpia.de, E-mail: henning@mpia.de, E-mail: anton.vasyunin@gmail.com, E-mail: tbirnstiel@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-03-20

    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 {approx}< 50 AU) and lower in the outer disk (R {approx}> 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{sub 2}, NH{sub 2}CN, HNO, H{sub 2}O, HCOOH, HCN, and CO. We also show that time-dependent chemistry is important for a proper description of gas thermal balance.

  4. Structural Evolution of Silicon Carbide Nanopowders during the Sintering Process

    Directory of Open Access Journals (Sweden)

    Galina Volkova

    2014-01-01

    Full Text Available Processes of sintering of silicon carbide nanopowder were investigated. Values of density (ρ=3.17 g/cm3 and strength (σ=450 MPa were obtained. Within the theory of dispersed systems, the temperature evolution of the materials structure was considered. The relationship between sintering temperature, characteristics of crystal structure and physical properties, in particular, density, and strength of aforementioned ceramics was established. It was concluded that it is necessary to suppress the anomalous diffusion at temperatures above 2080°C.

  5. Analysis of snowpack properties and structure from TerraSAR-X data, based on multilayer backscattering and snow evolution modeling approaches

    CERN Document Server

    Phan, Xuan-Vu; Gay, Michel; Durand, Yves; Dumont, Marie; Allain, Sophie; D'Urso, Guy

    2012-01-01

    Recently launched high precision Synthetic Aperture Radar (SAR) satellites such as TerraSAR-X, COSMO-SkyMed, etc. present a high potential for better observation and characterization of the cryosphere. This study introduces a new approach using high frequency (X-band) SAR data and an Electromagnetic Backscattering Model (EBM) to constrain the detailed snowpack model Crocus. A snowpack EBM based on radiative transfer theory, previously used for C-band applications, is adapted for the X-band. From measured or simulated snowpack stratigraphic profiles consisting of snow optical grain radius and density, this forward model calculates the backscattering coefficient for different polarimetric channels. The output result is then compared with spaceborne TerraSAR-X acquisitions to evaluate the forward model. Next, from the EBM, the adjoint operator is developed and used in a variational analysis scheme in order to minimize the discrepancies between simulations and SAR observations. A time series of TerraSAR-X acquisi...

  6. Evol and ProDy for bridging protein sequence evolution and structural dynamics

    Science.gov (United States)

    Mao, Wenzhi; Liu, Ying; Chennubhotla, Chakra; Lezon, Timothy R.; Bahar, Ivet

    2014-01-01

    Correlations between sequence evolution and structural dynamics are of utmost importance in understanding the molecular mechanisms of function and their evolution. We have integrated Evol, a new package for fast and efficient comparative analysis of evolutionary patterns and conformational dynamics, into ProDy, a computational toolbox designed for inferring protein dynamics from experimental and theoretical data. Using information-theoretic approaches, Evol coanalyzes conservation and coevolution profiles extracted from multiple sequence alignments of protein families with their inferred dynamics. Availability and implementation: ProDy and Evol are open-source and freely available under MIT License from http://prody.csb.pitt.edu/. Contact: bahar@pitt.edu PMID:24849577

  7. Analysis of the Characteristics in the Meudon Constrained Evolution Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Cordero-Carrion, I [Departamento de Astronomia y Astrofisica, Universidad de Valencia, Valencia (Spain); Ibanez, J M [Departamento de Astronomia y Astrofisica, Universidad de Valencia, Valencia (Spain); Jaramillo, J L [Instituto de Astrofisica de Andalucia (IAA-CSIC), Apartado 3004 18080 Granada (Spain); Gourgoulhon, E [Laboratoire de l' Univers et des Theories (LUTH), Observatoire de Paris, 92195 Meudon (France)

    2007-05-15

    A first analysis of the characteristics associated with the evolving modes in the constraint evolution scheme proposed by the Meudon group in 2004 is presented. The system is written in a first-order hyperbolic form and a so-called generalized Dirac gauge is considered. Applications to inner boundary conditions in an excised approach to black hole evolutions are discussed.

  8. 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...... 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...

  9. 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.

  10. Comparative Genome Analysis and Genome Evolution

    NARCIS (Netherlands)

    Snel, Berend

    2003-01-01

    This thesis described a collection of bioinformatic analyses on complete genome sequence data. We have studied the evolution of gene content and find that vertical inheritance dominates over horizontal gene trasnfer, even to the extent that we can use the gene content to make genome phylogenies. Usi

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

    OpenAIRE

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

    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%...

  12. A global analysis of adaptive evolution of operons in cyanobacteria.

    Science.gov (United States)

    Memon, Danish; Singh, Abhay K; Pakrasi, Himadri B; Wangikar, Pramod P

    2013-02-01

    Operons are an important feature of prokaryotic genomes. Evolution of operons is hypothesized to be adaptive and has contributed significantly towards coordinated optimization of functions. Two conflicting theories, based on (i) in situ formation to achieve co-regulation and (ii) horizontal gene transfer of functionally linked gene clusters, are generally considered to explain why and how operons have evolved. Furthermore, effects of operon evolution on genomic traits such as intergenic spacing, operon size and co-regulation are relatively less explored. Based on the conservation level in a set of diverse prokaryotes, we categorize the operonic gene pair associations and in turn the operons as ancient and recently formed. This allowed us to perform a detailed analysis of operonic structure in cyanobacteria, a morphologically and physiologically diverse group of photoautotrophs. Clustering based on operon conservation showed significant similarity with the 16S rRNA-based phylogeny, which groups the cyanobacterial strains into three clades. Clade C, dominated by strains that are believed to have undergone genome reduction, shows a larger fraction of operonic genes that are tightly packed in larger sized operons. Ancient operons are in general larger, more tightly packed, better optimized for co-regulation and part of key cellular processes. A sub-clade within Clade B, which includes Synechocystis sp. PCC 6803, shows a reverse trend in intergenic spacing. Our results suggest that while in situ formation and vertical descent may be a dominant mechanism of operon evolution in cyanobacteria, optimization of intergenic spacing and co-regulation are part of an ongoing process in the life-cycle of operons.

  13. Influence Activation Model: A New Perspective in Social Influence Analysis and Social Network Evolution

    CERN Document Server

    Yang, Yang; Lichtenwalter, Ryan N; Dong, Yuxiao

    2016-01-01

    What drives the propensity for the social network dynamics? Social influence is believed to drive both off-line and on-line human behavior, however it has not been considered as a driver of social network evolution. Our analysis suggest that, while the network structure affects the spread of influence in social networks, the network is in turn shaped by social influence activity (i.e., the process of social influence wherein one person's attitudes and behaviors affect another's). To that end, we develop a novel model of network evolution where the dynamics of network follow the mechanism of influence propagation, which are not captured by the existing network evolution models. Our experiments confirm the predictions of our model and demonstrate the important role that social influence can play in the process of network evolution. As well exploring the reason of social network evolution, different genres of social influence have been spotted having different effects on the network dynamics. These findings and ...

  14. Evolution of deep collapse caldera: from structural to gravitational process

    Science.gov (United States)

    Geshi, N.; Acocella, V.; Ruch, J.

    2012-04-01

    We discuss the evolution of deep-subsiding caldera mainly controlled by gravitational process. Progress of caldera subsidence increases its subsidence/diameter ratio (S/D ratio). We investigate the surface features of calderas undergoing significant subsidence with regard to their diameter. First, we consider the evolution of the 2000 Miyakejima caldera, from double-concentric ring faults at earlier collapsing stages, to a gravitational-erosion dominant stage at a mature stage. When the topographic S/D approaches 0.33, the topographic S/D (hereafter S/Dt) becomes significantly different from the structural S/D (hereafter S/Ds), owing to the gravitational erosion on the caldera wall and accumulation of the debris on the floor. As collapse progresses, the peripheral block bounded by the inner reverse fault and outer normal fault extends and tilts towards the caldera center; it finally collapses towards the caldera floor and the double-ring faults disappeares. Subsidence of the caldera floor induces the gravitational erosion of the wall. This process increases the topographic diameter and the filling of the floor decreases the topographic depth. Consequently, the S/Dt decreases, while the continuous caldera subsidence increases the S/Ds. This evolution finds close similarities with the caldera collapses of Krakatau (1883), Katmai (1912), Fernandina (1968), Tolbachik (1975-76), Pinatubo (1991) and Dolomieu (2007). Analogue experiments mimic the observed variation, evolving from a depression controlled by the activity of the double-ring faults to that controlled by the gravitational slumping of the wall and sedimentation at the floor. The transition occurs for S/Dt ~0.34. These results show that the control on the shape of mature calderas (S/Ds>0.07) and approaching S/Dt=0.3 passes from a mainly structural to a mainly gravitational type. Both S/Dt and S/Ds are needed to describe the evolution of a collapse and the processes accompanying it. Evaluating the S/Dt and S

  15. Evolution of Anabaenopeptin Peptide Structural Variability in the Cyanobacterium Planktothrix

    Science.gov (United States)

    Entfellner, Elisabeth; Frei, Mark; Christiansen, Guntram; Deng, Li; Blom, Jochen; Kurmayer, Rainer

    2017-01-01

    , Tyrosine, and Lysine in the exocyclic position of the AP-molecule. The increased structural diversity resulted from the evolution of apnA A1 genotypes through a small number of positively selected point mutations that occurred repeatedly and independently from phylogenetic association. PMID:28261178

  16. 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

  17. Nonsmooth analysis of doubly nonlinear evolution equations

    CERN Document Server

    Mielke, Alexander; Savare', Giuseppe

    2011-01-01

    In this paper we analyze a broad class of abstract doubly nonlinear evolution equations in Banach spaces, driven by nonsmooth and nonconvex energies. We provide some general sufficient conditions, on the dissipation potential and the energy functional,for existence of solutions to the related Cauchy problem. We prove our main existence result by passing to the limit in a time-discretization scheme with variational techniques. Finally, we discuss an application to a material model in finite-strain elasticity.

  18. Primary Cell Wall Structure in the Evolution of Land Plants

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Investigation of the primary cell walls of lower plants improves our understanding of the cell biology of these organisms but also has the potential to improve our understanding of cell wall structure and function in angiosperms that evolved from lower plants. Cell walls were prepared from eight species, ranging from a moss to advanced gymnosperms, and subjected to sequential chemical extraction to separate the main polysaccharide fractions. The glycosyl compositions of these fractions were then determined by gas chromatography. The results were compared among the eight plants and among data from related studies reported in the existing published reports to identify structural features that have been either highly conserved or clearly modified during evolution. Among the highly conserved features are the presence of a cellulose framework, the presence of certain hemicelluloses such as xyloglucan, and the presence of rhamnogalacturonan Ⅱ, a domain in pectic polysaccharides. Among the modified features are the abundance of mannosyl-containing hemicelluloses and the presence of methylated sugars.

  19. Dynamical evolution of the community structure of complex earthquake network

    CERN Document Server

    Abe, Sumiyoshi

    2012-01-01

    Earthquake network is known to be complex in the sense that it is scale-free, small-world, hierarchically organized and assortatively mixed. Here, the time evolution of earthquake networks is analyzed around main shocks in the context of the community structure. It is found that the maximum of the modularity measure quantifying existence of communities exhibits a peculiar behavior: its maximum value stays at a large value before a main shock, suddenly drops to a small values at the main shock, and then increases to relax to a large value again relatively slowly. In this way, a main shock is characterized in the language of theory of complex networks. The result is also interpreted in terms of the clustering structure of the earthquake network.

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

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    2004-01-01

    In this paper it is argued that evolutionary economics needs general statistical tools for performing the analysis of the aggregate effects of evolution in terms of the underlying population dynamics. These tools have been developed within biometrics, and they have recently become directly...... 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...

  1. egoSlider: Visual Analysis of Egocentric Network Evolution.

    Science.gov (United States)

    Wu, Yanhong; Pitipornvivat, Naveen; Zhao, Jian; Yang, Sixiao; Huang, Guowei; Qu, Huamin

    2016-01-01

    Ego-network, which represents relationships between a specific individual, i.e., the ego, and people connected to it, i.e., alters, is a critical target to study in social network analysis. Evolutionary patterns of ego-networks along time provide huge insights to many domains such as sociology, anthropology, and psychology. However, the analysis of dynamic ego-networks remains challenging due to its complicated time-varying graph structures, for example: alters come and leave, ties grow stronger and fade away, and alter communities merge and split. Most of the existing dynamic graph visualization techniques mainly focus on topological changes of the entire network, which is not adequate for egocentric analytical tasks. In this paper, we present egoSlider, a visual analysis system for exploring and comparing dynamic ego-networks. egoSlider provides a holistic picture of the data through multiple interactively coordinated views, revealing ego-network evolutionary patterns at three different layers: a macroscopic level for summarizing the entire ego-network data, a mesoscopic level for overviewing specific individuals' ego-network evolutions, and a microscopic level for displaying detailed temporal information of egos and their alters. We demonstrate the effectiveness of egoSlider with a usage scenario with the DBLP publication records. Also, a controlled user study indicates that in general egoSlider outperforms a baseline visualization of dynamic networks for completing egocentric analytical tasks.

  2. 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

  3. Nonlinear evolution of large-scale structure in the universe

    Energy Technology Data Exchange (ETDEWEB)

    Frenk, C.S.; White, S.D.M.; Davis, M.

    1983-08-15

    Using N-body simulations we study the nonlinear development of primordial density perturbation in an Einstein--de Sitter universe. We compare the evolution of an initial distribution without small-scale density fluctuations to evolution from a random Poisson distribution. These initial conditions mimic the assumptions of the adiabatic and isothermal theories of galaxy formation. The large-scale structures which form in the two cases are markedly dissimilar. In particular, the correlation function xi(r) and the visual appearance of our adiabatic (or ''pancake'') models match better the observed distribution of galaxies. This distribution is characterized by large-scale filamentary structure. Because the pancake models do not evolve in a self-similar fashion, the slope of xi(r) steepens with time; as a result there is a unique epoch at which these models fit the galaxy observations. We find the ratio of cutoff length to correlation length at this time to be lambda/sub min//r/sub 0/ = 5.1; its expected value in a neutrino dominated universe is 4(..cap omega..h)/sup -1/ (H/sub 0/ = 100h km s/sup -1/ Mpc/sup -1/). At early epochs these models predict a negligible amplitude for xi(r) and could explain the lack of measurable clustering in the Ly..cap alpha.. absorption lines of high-redshift quasars. However, large-scale structure in our models collapses after z = 2. If this collapse precedes galaxy formation as in the usual pancake theory, galaxies formed uncomfortably recently. The extent of this problem may depend on the cosmological model used; the present series of experiments should be extended in the future to include models with ..cap omega..<1.

  4. Investigation impact of stressed state conditions and thermomechanical parameters on the texture and structure evolution in 1565ph aluminium alloy

    Science.gov (United States)

    Yashin, V. V.; Aryshensky, E. V.; Kawalla, R. F.; Serebryany, V. N.; Rushchits, S. V.

    2016-11-01

    The paper is devoted to study of the impact stress condition and thermomechanical treatment parameters on the structure and texture evolution of new 1565 ph aluminum alloy. For that purposes, we use test on Gleeble equipment, FM calculation, optical microscopy and x ray diffraction texture analysis. The dependency between the deformation texture components development and strain rate value was established. Differences in the texture evolution at uniaxial compression stress and plain strain mode were revealed.

  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. Molecular dynamics simulations of the structure evolutions of Cu-Zr metallic glasses under irradiation

    Science.gov (United States)

    Lang, Lin; Tian, Zean; Xiao, Shifang; Deng, Huiqiu; Ao, Bingyun; Chen, Piheng; Hu, Wangyu

    2017-02-01

    Molecular dynamics simulations have been performed to investigate the structural evolution of Cu64.5Zr35.5 metallic glasses under irradiation. The largest standard cluster analysis (LSCA) method was used to quantify the microstructure within the collision cascade regions. It is found that the majority of clusters within the collision cascade regions are full and defective icosahedrons. Not only the smaller structures (common neighbor subcluster) but also primary clusters greatly changed during the collision cascades; while most of these radiation damages self-recover quickly in the following quench states. These findings indicate the Cu-Zr metallic glasses have excellent irradiation-resistance properties.

  7. The evolution of chloroplast genome structure in ferns.

    Science.gov (United States)

    Wolf, Paul G; Roper, Jessie M; Duffy, Aaron M

    2010-09-01

    The plastid genome (plastome) is a rich source of phylogenetic and other comparative data in plants. Most land plants possess a plastome of similar structure. However, in a major group of plants, the ferns, a unique plastome structure has evolved. The gene order in ferns has been explained by a series of genomic inversions relative to the plastome organization of seed plants. Here, we examine for the first time the structure of the plastome across fern phylogeny. We used a PCR-based strategy to map and partially sequence plastomes. We found that a pair of partially overlapping inversions in the region of the inverted repeat occurred in the common ancestor of most ferns. However, the ancestral (seed plant) structure is still found in early diverging branches leading to the osmundoid and filmy fern lineages. We found that a second pair of overlapping inversions occurred on a branch leading to the core leptosporangiates. We also found that the unique placement of the gene matK in ferns (lacking a flanking intron) is not a result of a large-scale inversion, as previously thought. This is because the intron loss maps to an earlier point on the phylogeny than the nearby inversion. We speculate on why inversions may occur in pairs and what this may mean for the dynamics of plastome evolution.

  8. Astrocladistics: a phylogenetic analysis of galaxy evolution I. Character evolutions and galaxy histories

    CERN Document Server

    Fraix-Burnet, D; Douzery, E J P; Verhamme, A; Fraix-Burnet, Didier; Choler, Philippe; Douzery, Emmanuel J.P.; Verhamme, Anne

    2006-01-01

    This series of papers is intended to present astrocladistics in some detail and evaluate this methodology in reconstructing phylogenies of galaxies. Being based on the evolution of all the characters describing galaxies, it is an objective way of understanding galaxy diversity through evolutionary relationships. In this first paper, we present the basic steps of a cladistic analysis and show both theoretically and practically that it can be applied to galaxies. For illustration, we use a sample of 50 simulated galaxies taken from the GALICS database, which are described by 91 observables (dynamics, masses and luminosities). These 50 simulated galaxies are indeed 10 different galaxies taken at 5 cosmological epochs, and they are free of merger events. The astrocladistic analysis easily reconstructs the true chronology of evolution relationships within this sample. It also demonstrates that burst characters are not relevant for galaxy evolution as a whole. A companion paper is devoted to the formalization of th...

  9. The evolution of capital structure theories and their classification

    Directory of Open Access Journals (Sweden)

    Natalia Korzh

    2015-05-01

    Full Text Available The article deals with existing approaches of determining the optimal capital structure. Joint-stock companies operation calls for improving the capital structure aimed at the stockholder equity rise in profitability. In this case, the interests of capital owners and management may not coincide. The existing approaches distribution to two groups based on the conceptual approaches analysis dealing with optimal capital structure determination has been made. One group, called “static”, determine the optimal capital structure by current assets evaluation maximization, the other, called “dynamic”, is liable to variations of target capital structure at the certain moment. Theories within these groups were classified and their characteristic features were described on the basis of theoretical ideas of optimal capital structure peculiarities.

  10. Green chemistry and the evolution of flow analysis. A review.

    Science.gov (United States)

    Melchert, Wanessa R; Reis, Boaventura F; Rocha, Fábio R P

    2012-02-10

    Flow analysis has achieved its majority as a well-established tool to solve analytical problems. Evolution of flow-based approaches has been analyzed by diverse points of view, including historical aspects, the commutation concept and the impact on analytical methodologies. In this overview, the evolution of flow analysis towards green analytical chemistry is demonstrated by comparing classical procedures implemented with different flow approaches. The potential to minimize reagent consumption and waste generation and the ability to implement processes unreliable in batch to replace toxic chemicals are also emphasized. Successful applications of greener approaches in flow analysis are also discussed, focusing on the last 10 years.

  11. Wound Image Analysis Using Contour Evolution

    Directory of Open Access Journals (Sweden)

    K. Sundeep Kumar

    2014-05-01

    Full Text Available The aim of the algorithm described in this paper is to segment wound images from the normal and classify them according to the types of the wound. The segmentation of wounds extravagates color representation, which has been followed by an algorithm of grayscale segmentation based on the stack mathematical approach. Accurate classification of wounds and analyzing wound healing process is a critical task for patient care and health cost reduction at hospital. The tissue uniformity and flatness leads to a simplified approach but requires multispectral imaging for enhanced wound delineation. Contour Evolution method which uses multispectral imaging replaces more complex tools such as, SVM supervised classification, as no training step is required. In Contour Evolution, classification can be done by clustering color information, with differential quantization algorithm, the color centroids of small squares taken from segmented part of the wound image in (C1,C2 plane. Where C1, C2 are two chrominance components. Wound healing is identified by measuring the size of the wound through various means like contact and noncontact methods of wound. The wound tissues proportion is also estimated by a qualitative visual assessment based on the red-yellow-black code. Moreover, involving all the spectral response of the tissue and not only RGB components provides a higher discrimination for separating healed epithelial tissue from granulation tissue.

  12. 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.

  13. The Interior Structure, Composition, and Evolution of Giant Planets

    CERN Document Server

    Fortney, Jonathan J

    2009-01-01

    We discuss our current understanding of the interior structure and thermal evolution of giant planets. This includes the gas giants, such as Jupiter and Saturn, that are primarily composed of hydrogen and helium, as well as the "ice giants," such as Uranus and Neptune, which are primarily composed of elements heavier than H/He. The effect of different hydrogen equations of state (including new first-principles computations) on Jupiter's core mass and heavy element distribution is detailed. This variety of the hydrogen equations of state translate into an uncertainty in Jupiter's core mass of 18 M_Earth. For Uranus and Neptune we find deep envelope metallicities up to 0.95, perhaps indicating the existence of an eroded core, as also supported by their low luminosity. We discuss the results of simple cooling models of our solar system's planets, and show that more complex thermal evolution models may be necessary to understand their cooling history. We review how measurements of the masses and radii of the ~50 ...

  14. Structure and evolution of low-mass stars

    CERN Document Server

    Chabrier, G; Chabrier, Gilles; Baraffe, Isabelle

    1997-01-01

    We present extensive calculations of the structure and the evolution of low-massstars in the range 0.07-0.8 $\\msol$, for metallicities $-2.0\\le \\mh \\le 0.0$. These calculations are based on the most recent description of the microphysics characteristic of these dense and cool objects and on the lattest generation of grainless non-grey atmosphere models. We examine the evolution of the different mechanical and thermal properties of these objects as a function of mass and metallicity. We also demonstrate the inaccuracy of grey models and $T(\\tau)$ relationships under these conditions. We provide detailed tables of the mass-radius-luminosity-effective temperature relations for various ages and metallicities, aimed at calibrating existing or future observations of low-mass stars and massive brown dwarfs. We derive new hydrogen-burning minimum masses, within the afore-mentioned metallicity range. These minimum masses are found to be smaller than previous estimates, a direct consequence of non-grey effects. At last...

  15. Cooling-induced structure formation and evolution in collapsars

    CERN Document Server

    Batta, Aldo

    2013-01-01

    The collapse of massive rotating stellar cores and the associated accretion onto the newborn compact object is thought to power long gamma ray bursts (GRBs). The physical scale and dynamics of the accretion disk are initially set by the angular momentum distribution in the progenitor, and the physical conditions make neutrino emission the main cooling agent in the flow. The formation and evolution of structure in these disks is potentially very relevant for the energy release and its time variability, which ultimately imprint on the observed GRB properties. To begin to characterize these, taking into account the three dimensional nature of the problem, we have carried out an initial set of calculations of the collapse of rotating polytropic cores in three dimensions, making use of a pseudo-relativistic potential and a simplified cooling prescription. We focus on the effects of self gravity and cooling on the overall morphology and evolution of the flow for a given rotation rate in the context of the collapsar...

  16. 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.

  17. Structure and Evolution of Internally Heated Hot Jupiters

    Science.gov (United States)

    Komacek, Thaddeus D.; Youdin, Andrew N.

    2015-11-01

    The transit radii of many close-in extrasolar giant planets, or "hot Jupiters," are systematically larger than those expected from models considering only cooling from an initial high-entropy state. Though these planets receive strong irradiation, with equilibrium temperatures of 1000-2500 Kelvin, the absorption of stellar incident flux in the upper atmosphere alone cannot explain these anomalous radii. More promising mechanisms involve irradiation-driven meteorological activity, which penetrates much deeper into the planet than direct stellar heating. This circulation can lead to large-scale mixing and downward transport of kinetic energy, both processes whereby a fraction of the stellar incident power is transported downwards to the interior of the planet. Here we consider how deposition of heat at different pressure levels or structural locations within a planet affects the resulting evolution. To do so, we run global gas giant evolutionary models with with the stellar structure code MESA including additional energy dissipation. We find that relatively shallow atmospheric heating alone can explain the transit radii of the hot Jupiter sample, but heating in the convective zone is an order of magnitude more efficient regardless of exact location. Additionally, a small difference in atmospheric heating location can have a significant effect on radius evolution, especially near the radiative-convective boundary. The most efficient location to heat the planet is at the radiative-convective boundary or deeper. We expect that shear instabilities at this interface may naturally explain energy dissipation at the radiative-convective boundary, which typically lies at a pressure of ~1 kilobar after 5 Gyr for a planet with the mass and incident stellar flux of HD 209458b. Hence, atmospheric processes are most efficient at explaining the bloated radii of hot Jupiters if they can transport incident stellar power downwards to the top of the inner convective zone.

  18. 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.

  19. Grain structure evolution during cryogenic rolling of alpha brass

    Energy Technology Data Exchange (ETDEWEB)

    Konkova, T. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); Mironov, S. [Department of Materials Processing, Graduate School of Engineering, Tohoku University, 6-6-02 Aramaki-aza-Aoba, Sendai 980-8579 (Japan); Korznikov, A. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); National Research Tomsk State University, 36 Lenina av., Tomsk 634050 (Russian Federation); Korznikova, G. [Institute for Metals Superplasticity Problems, Rssian Academy of Science, 39 Khalturin Str., Ufa 450001 (Russian Federation); Myshlyaev, M.M. [Baikov Institute of Metallurgy and Material Science, Russian Academy of Science, 49 Lenin-av., Moscow 119991 (Russian Federation); Semiatin, S.L. [Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RXCM, Wright-Patterson AFB, OH 45433-7817 (United States)

    2015-04-25

    Highlights: • Cryogenic rolling produced inhomogeneous ultrafine-grained microstructure. • Grain refinement was mainly related with twinning and shear banding. • Grain refinement preferentially occurred in Copper {1 1 0}(1 1 2) grains. - Abstract: High-resolution electron backscatter diffraction (EBSD) was used to study grain structure development during cryogenic rolling of Cu–29.5Zn brass. Microstructure evolution was found to be broadly similar to that occurring during rolling at room temperature. Specifically, favorably-oriented grains (Copper {1 1 2}(1 1 1) and S {1 2 3}(6 3 4)) experienced profuse deformation twinning followed by extensive shear banding. This eventually produced an ultrafine structure with a mean grain size of ~0.2 μm. On the other hand, grains with crystallographic orientations close to Brass {1 1 0}(1 1 2) and Goss {1 1 0}(1 0 0) were found to be stable against twinning/shear banding and thus showed no significant grain refinement. As a result, the final structure developed in heavily-rolled material was distinctly inhomogeneous consisting of mm-scale remnants of original grains with poorly developed substructure and ultra-fine grain domains.

  20. Halo formation and evolution: unifying physical properties with structure

    Science.gov (United States)

    Ernest, Alllan David; Collins, Matthew P.

    2015-08-01

    The assembly of matter in the universe proliferates a variety of structures with diverse properties. For example, massive halos of clusters of galaxies have temperatures often an order of magnitude or more higher than the individual galaxy halos within the cluster, or the temperatures of isolated galaxy halos. Giant spiral galaxies contain large quantities of both dark matter and hot gas while other structures like globular clusters appear to have little or no dark matter or gas. Still others, like the dwarf spheroidal galaxies have low gravity and little hot gas, but ironically contain some of the largest fractions of dark matter in the universe. Star forming rates (SFRs) also vary: compare for example the SFRs of giant elliptical galaxies, globular clusters, spiral and starburst galaxies. Furthermore there is evidence that the various structure types have existed over a large fraction of cosmic history. How can this array of variation in properties be reconciled with galaxy halo formation and evolution?We propose a model of halo formation [1] and evolution [2] that is consistent with both primordial nucleosynthesis (BBN) and the isotropies in the cosmic microwave background (CMB). The model uses two simple parameters, the total mass and size of a structure, to (1) explain why galaxies have the fractions of dark matter that they do (including why dwarf spheroidals are so dark matter dominated despite their weak gravity), (2) enable an understanding of the black hole-bulge/black hole-dark halo relations, (3) explain how fully formed massive galaxies can occur so early in cosmic history, (4) understand the connection between spiral and elliptical galaxies (5) unify the nature of globular clusters, dwarf spheroidal galaxies and bulges and (6) predict the temperatures of hot gas halos and understand how cool galaxy halos can remain stable in the hot environments of cluster-galaxy halos.[1] Ernest, A. D., 2012, in Prof. Ion Cotaescu (Ed) Advances in Quantum Theory, pp

  1. Thermal evolution of the crystal structure of the orthorhombic perovskite LaFeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Charlotte A.L.; Kavanagh, Christopher M. [School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST (United Kingdom); Knight, Kevin S.; Kockelmann, Winfried [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Morrison, Finlay D. [School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST (United Kingdom); Lightfoot, Philip, E-mail: pl@st-and.ac.uk [School of Chemistry and EaStCHEM, University of St Andrews, St Andrews KY16 9ST (United Kingdom)

    2015-10-15

    The thermal evolution of the crystal structure of the prototypical orthorhombic perovskite LaFeO{sub 3} has been studied in detail by powder neutron diffraction in the temperature range 25analysis, combined with an analysis in terms of symmetry-adapted modes, allows key aspects of the thermal behavior to be understood. In particular, the largest-amplitude symmetry modes (viz. in-phase and out-of-phase octahedral tilts, and A-site cation displacements) are shown to display relatively ‘normal’ behavior, increasing with decreasing temperature, which contrasts with the anomalous behavior previously shown by the derivative Bi{sub 0.5}La{sub 0.5}FeO{sub 3}. However, an unexpected behavior is seen in the nature of the intra-octahedral distortion, which is used to rationalize the unique occurrence of a temperature dependent crossover of the a and c unit cell metrics in this compound. - Graphical abstract: The unusual thermal evolution of lattice metrics in the perovskite LaFeO{sub 3} is rationalized from a detailed powder neutron diffraction study. - Highlights: • Crystal structure of the perovskite LaFeO{sub 3} studied in detail by powder neutron diffraction. • Unusual thermal evolution of lattice metrics rationalized. • Contrasting behavior to Bi-doped LaFeO{sub 3}. • Octahedral distortion/tilt parameters explain unusual a and c lattice parameter behavior.

  2. 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...

  3. Structured Analysis - IDEF0

    DEFF Research Database (Denmark)

    Larsen, Michael Holm

    1999-01-01

    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...

  4. 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

  5. 基于概率密度演化的渡槽结构抗震分析%Seismic Analysis of Large-scale Aqueduct Structures Based on the Probability Density Evolution Method

    Institute of Scientific and Technical Information of China (English)

    曾波; 邢彦富; 刘章军

    2014-01-01

    Using the orthogonal expansion method of random processes,the non-stationary seismic acceleration process is represented as a linear combination of the standard orthogonal basis func-tions and the standard orthogonal random variables.Then,using the random function,these stand-ard orthogonal random variables in the orthogonal expansion are expressed as an orthogonal func-tion form of the basic random variable.Therefore,this method can use a basic random variable to express the original earthquake ground processes.The orthogonal expansion-random function ap-proach was used to generate 126 representative earthquake samples,and each representative sam-ple was assigned a given probability.The 126 representative earthquake samples were combined with the probability density evolution method of stochastic dynamical systems and random seis-mic responses of large-scale aqueduct structures was investigated.In this study,four cases were considered;aqueduct without water,aqueduct with water in the central trough,aqueduct with wa-ter in a two-side trough,and aqueduct with water in three troughs,and probability information of seismic responses for these cases were obtained.Moreover,using the proposed method,the seis-mic reliability of the aqueduct structures was efficiently calculated.This method provides a new and effective means for precise seismic analysis of large-scale aqueduct structures.%应用随机过程的正交展开方法,将地震动加速度过程展开为标准正交基函数与标准正交随机变量的线性组合形式。在此基础上采用随机函数的思想,将正交展开式中的标准正交随机变量表达为基本随机变量的函数形式,从而实现用一个基本随机变量来表达原地震动过程的目的。结合地震动过程的正交展开-随机函数模型与概率密度演化方法,对某大型渡槽结构进行随机地震反应分析与抗震可靠度计算;重点研究空槽和三槽有水等四种工况下渡槽结构

  6. 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.

  7. Structural Evolution of Household Energy Consumption: A China Study

    Directory of Open Access Journals (Sweden)

    Qingsong Wang

    2015-04-01

    Full Text Available Sustainable energy production and consumption is one of the issues for the sustainable development strategy in China. As China’s economic development paradigm shifts, household energy consumption (HEC has become a focus of achieving national goals of energy efficiency and greenhouse gas reduction. The information entropy model and LMDI model were employed in this study in order to analyse the structural evolution of HEC, as well as its associated critical factors. The results indicate that the information entropy of HEC increased gradually, and coal will be reduced by clean energies, such as natural gas and liquefied petroleum gas. The information entropy tends to stabilize and converge due to rapid urbanization. Therefore, from the perspective of environmental protection and natural resource conservation, the structure of household energy consumption will be optimized. This study revealed that residents’ income level is one of the most critical factors for the increase of energy consumption, while the energy intensity is the only driving force for the reduction of HEC. The accumulated contribution of these two factors to the HEC is 240.53% and −161.75%, respectively. It is imperative to improve the energy efficiency in the residential sector. Recommendations are provided to improve the energy efficiency-related technologies, as well as the standards for the sustainable energy strategy.

  8. Analysis of intratumor heterogeneity unravels lung cancer evolution

    OpenAIRE

    Bruin, Elza C de; McGranahan, Nicholas; Swanton, Charles

    2015-01-01

    Lung cancer is a disease with dismal outcome. We recently reported a detailed intratumor heterogeneity analysis in 7 non-small cell lung cancer samples, revealing spatially separated driver events as well as the temporal dynamics of mutational processes and demonstrating an important role for APOBEC-mediated heterogeneity later in disease evolution.

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

    Science.gov (United States)

    Masera, D.; Bocca, P.; Grazzini, A.

    2011-07-01

    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.

  10. The structural evolution of the deep continental lithosphere

    Science.gov (United States)

    Cooper, C. M.; Miller, Meghan S.; Moresi, Louis

    2017-01-01

    Continental lithosphere houses the oldest and thickest regions of the Earth's surface. Locked within this deep and ancient rock record lies invaluable information about the dynamics that has shaped and continue to shape the planet. Much of that history has been dominated by the forces of plate tectonics which has repeatedly assembled super continents together and torn them apart - the Wilson Cycle. While the younger regions of continental lithosphere have been subject to deformation driven by plate tectonics, it is less clear whether the ancient, stable cores formed and evolved from similar processes. New insight into continental formation and evolution has come from remarkable views of deeper lithospheric structure using enhanced seismic imaging techniques and the increase in large volumes of broadband data. Some of the most compelling observations are that the continental lithosphere has a broad range in thicknesses ( 300 km), has complex internal structure, and that the thickest portion appears to be riddled with seismic discontinuities at depths between 80 and 130 km. These internal structural features have been interpreted as remnants of lithospheric formation during Earth's early history. If they are remnants, then we can attempt to investigate the structure present in the deep lithosphere to piece together information about early Earth dynamics much as is done closer to the surface. This would help delineate between the differing models describing the dynamics of craton formation, particularly whether they formed in the era of modern plate tectonics, a transitional mobile-lid tectonic regime, or are the last fragments of an early, stagnant-lid planet. Our review paper (re)introduces readers to the conceptual definitions of the lithosphere and the complex nature of the upper boundary layer, then moves on to discuss techniques and recent seismological observations of the continental lithosphere. We then review geodynamic models and hypotheses for the formation

  11. Failure Analysis of Wind Turbines by Probability Density Evolution Method

    DEFF Research Database (Denmark)

    Sichani, Mahdi Teimouri; Nielsen, Søren R.K.; Liu, W.F.

    2013-01-01

    The aim of this study is to present an efficient and accurate method for estimation of the failure probability of wind turbine structures which work under turbulent wind load. The classical method for this is to fit one of the extreme value probability distribution functions to the extracted maxima....... This is not practical due to its excessive computational load. This problem can alternatively be tackled if the evolution of the probability density function (PDF) of the response process can be realized. The evolutionary PDF can then be integrated on the boundaries of the problem. For this reason we propose to use...... the Probability Density Evolution Method (PDEM). PDEM can alternatively be used to obtain the distribution of the extreme values of the response process by simulation. This approach requires less computational effort than integrating the evolution of the PDF; but may be less accurate. In this paper we present...

  12. Boltzmann, Lotka and Volterra and spatial structural evolution: an integrated methodology for some dynamical systems.

    Science.gov (United States)

    Wilson, Alan

    2008-08-01

    It is shown that Boltzmann's methods from statistical physics can be applied to a much wider range of systems, and in a variety of disciplines, than has been commonly recognized. A similar argument can be applied to the ecological models of Lotka and Volterra. Furthermore, it is shown that the two methodologies can be applied in combination to generate the Boltzmann, Lotka and Volterra (BLV) models. These techniques enable both spatial interaction and spatial structural evolution to be modelled, and it is argued that they potentially provide a much richer modelling methodology than that currently used in the analysis of 'scale-free' networks.

  13. The structure and evolution of the stratospheric vortex in response to natural forcings

    Science.gov (United States)

    Mitchell, D. M.; Gray, L. J.; Charlton-Perez, A. J.

    2011-08-01

    The structure and evolution of the Arctic stratospheric polar vortex is assessed during opposing phases of, primarily, the El Niño-Southern Oscillation (ENSO) and the Quasi-Biennial Oscillation (QBO), but the 11 year solar cycle and winters following large volcanic eruptions are also examined. The analysis is performed by taking 2-D moments of vortex potential vorticity (PV) fields which allow the area and centroid of the vortex to be calculated throughout the ERA-40 reanalysis data set (1958-2002). Composites of these diagnostics for the different phases of the natural forcings are then considered. Statistically significant results are found regarding the structure and evolution of the vortex during, in particular, the ENSO and QBO phases. When compared with the more traditional zonal mean zonal wind diagnostic at 60°N, the moment-based diagnostics are far more robust and contain more information regarding the state of the vortex. The study details, for the first time, a comprehensive sequence of events which map the evolution of the vortex during each of the forcings throughout an extended winter period.

  14. 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...... 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...... 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...

  15. Comparative Analysis of the Value Added Tax Evolution

    Directory of Open Access Journals (Sweden)

    Mirela Anca Postole

    2013-06-01

    Full Text Available The impact of indirect taxes is analysed in the study of evolution, especially the VAT for the economic activity of the company studied. During the reporting period, namely January 2009 – December 2011 the supporting documents were checked which records on VAT deductible and collected were based on, in compliance with legal norms and principles of financial accounting. Also the data processed were the basis for an analysis to compare the evolution of VAT. VAT shall be paid for the entire activity of the company.

  16. Evolution of grain structures during directional solidification of silicon wafers

    Science.gov (United States)

    Lin, H. K.; Wu, M. C.; Chen, C. C.; Lan, C. W.

    2016-04-01

    The evolution of grain structures, especially the types of grain boundaries (GBs), during directional solidification is crucial to the electrical properties of multicrystalline silicon used for solar cells. To study this, the electric molten zone crystallization (EMZC) of silicon wafers at different drift speeds from 2 to 6 mm/min was considered. It was found that orientation was dominant at the lower drift velocity, while orientation at the higher drift velocity. Most of the non-∑GBs tended to align with the thermal gradient, but some tilted toward the unfavorable grains having higher interfacial energies. On the other hand, the tilted ∑3GBs tended to decrease during grain competition, except at the higher speed, where the twin nucleation became frequent. The competition of grains separated by ∑GBs could be viewed as the interactions of GBs that two coherent ∑3n GBs turned into one ∑3nGB following certain relations as reported before. On the other hand, when ∑ GBs met non-∑ GBs, the non-∑ GBs remained which explained the decrease of ∑ GBs at the lower speed.

  17. Interactive diversity promotes the evolution of cooperation in structured populations

    Science.gov (United States)

    Su, Qi; Li, Aming; Zhou, Lei; Wang, Long

    2016-10-01

    Evolutionary games on networks traditionally assume that each individual adopts an identical strategy to interact with all its neighbors in each generation. Considering the prevalent diversity of individual interactions in the real society, here we propose the concept of interactive diversity, which allows individuals to adopt different strategies against different neighbors in each generation. We investigate the evolution of cooperation based on the edge dynamics rather than the traditional nodal dynamics in networked systems. The results show that, without invoking any other mechanisms, interactive diversity drives the frequency of cooperation to a high level for a wide range of parameters in both well-mixed and structured populations. Even in highly connected populations, cooperation still thrives. When interactive diversity and large topological heterogeneity are combined together, however, in the relaxed social dilemma, cooperation level is lower than that with just one of them, implying that the combination of many promotive factors may make a worse outcome. By an analytical approximation, we get the condition under which interactive diversity provides more advantages for cooperation than traditional evolutionary dynamics does. Numerical simulations validating the approximation are also presented. Our work provides a new line to explore the latent relation between the ubiquitous cooperation and individuals’ distinct responses in different interactions. The presented results suggest that interactive diversity should receive more attention in pursuing mechanisms fostering cooperation.

  18. A probabilistic model for the evolution of RNA structure

    Directory of Open Access Journals (Sweden)

    Holmes Ian

    2004-10-01

    Full Text Available Abstract Background For the purposes of finding and aligning noncoding RNA gene- and cis-regulatory elements in multiple-genome datasets, it is useful to be able to derive multi-sequence stochastic grammars (and hence multiple alignment algorithms systematically, starting from hypotheses about the various kinds of random mutation event and their rates. Results Here, we consider a highly simplified evolutionary model for RNA, called "The TKF91 Structure Tree" (following Thorne, Kishino and Felsenstein's 1991 model of sequence evolution with indels, which we have implemented for pairwise alignment as proof of principle for such an approach. The model, its strengths and its weaknesses are discussed with reference to four examples of functional ncRNA sequences: a riboswitch (guanine, a zipcode (nanos, a splicing factor (U4 and a ribozyme (RNase P. As shown by our visualisations of posterior probability matrices, the selected examples illustrate three different signatures of natural selection that are highly characteristic of ncRNA: (i co-ordinated basepair substitutions, (ii co-ordinated basepair indels and (iii whole-stem indels. Conclusions Although all three types of mutation "event" are built into our model, events of type (i and (ii are found to be better modeled than events of type (iii. Nevertheless, we hypothesise from the model's performance on pairwise alignments that it would form an adequate basis for a prototype multiple alignment and genefinding tool.

  19. Structure Shape Evolution in Lanthanide and Actinide Nuclei

    Directory of Open Access Journals (Sweden)

    Khalaf A. M.

    2013-04-01

    Full Text Available To give the characteristics of the evolution of the collectivity in even-even nuclei, we studied the behavior of the energy ratios R(4 / 2 and R(6 / 4. All chains of lanthanides begins as vibrational with R(4 / 2 near 2.0 and move towards rotational (R(4 / 2 3.33 as neutron number increases. A rabid jump in R(4 / 2 near N = 90 was seen. The plot of R(4 / 2 against Z shows not only the existence of a shape transitions but also the change in curvature in the data for N = 88 and 90, concave to convex. For intermedi- ate structure the slopes in E-GOS ( E over spin plots range between the vibrator and rotor extremes. The abnormal behavior of the two-neutron separation energies of our lanthanide nuclei as a function of neutron number around neutron number 90 is cal- culated. Nonlinear behavior is observed which indicate that shape phase transition is occurred in this region. The calculated reduced B(E2 transition probabilities of the low states of the ground state band in the nuclei 150 Nd / 152 Sm / 154 Gd / 156 Dy are analyzed and compared to the prediction of vibrational U(5 and rotational SU(3 limits of interacting boson model calculations.

  20. 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.

  1. Mutation rates and the evolution of germline structure

    Science.gov (United States)

    2016-01-01

    Genome sequencing studies of de novo mutations in humans have revealed surprising incongruities in our understanding of human germline mutation. In particular, the mutation rate observed in modern humans is substantially lower than that estimated from calibration against the fossil record, and the paternal age effect in mutations transmitted to offspring is much weaker than expected from our long-standing model of spermatogenesis. I consider possible explanations for these discrepancies, including evolutionary changes in life-history parameters such as generation time and the age of puberty, a possible contribution from undetected post-zygotic mutations early in embryo development, and changes in cellular mutation processes at different stages of the germline. I suggest a revised model of stem-cell state transitions during spermatogenesis, in which ‘dark’ gonial stem cells play a more active role than hitherto envisaged, with a long cycle time undetected in experimental observations. More generally, I argue that the mutation rate and its evolution depend intimately on the structure of the germline in humans and other primates. This article is part of the themed issue ‘Dating species divergences using rocks and clocks'. PMID:27325834

  2. Evolution by structural polymorphism in a Miocene neogastropod

    Energy Technology Data Exchange (ETDEWEB)

    Allmon, W.D.

    1985-01-01

    Morphological change in the shallow marine species Bullia (Bulliopsis) quadrata (Nassariidae) from the middle to late Miocene of Maryland and Virginia seems to have been by anagenesis within a single lineage rather than by cladogenesis, or associated with a speciation event. The mechanism for this change seems to have been a shift in frequency of a shell form polymorphism. When B.quadrata first appears in the lower St. Mary's Fm., all individuals show a similar smooth shell form. In the middle St. Mary's a distinct carinate morphotype appears, represented by only a few individuals. In the upper St. Mary's a higher proportion of these more ornate forms occurs. Finally in the upper member of the overlying Eastover Fm. the ornate morphology becomes dominant. Specimens from the Eastover Fm. are not only mostly of the more ornate type, but maximum size has increased and the ornate morphology has become more pronounced. This occurs in an area geographically and ecologically marginal to the previous main species range and so may represent an ecophenotypic effect. The genetics of gastropod shell form are very poorly understood. This study represents one of the few documented examples of the role of structural polymorphism in gastropod evolution.

  3. 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

  4. Structure and evolution of the global seafood trade network

    Science.gov (United States)

    Gephart, Jessica A.; Pace, Michael L.

    2015-12-01

    The food production system is increasingly global and seafood is among the most highly traded commodities. Global trade can improve food security by providing access to a greater variety of foods, increasing wealth, buffering against local supply shocks, and benefit the environment by increasing overall use efficiency for some resources. However, global trade can also expose countries to external supply shocks and degrade the environment by increasing resource demand and loosening feedbacks between consumers and the impacts of food production. As a result, changes in global food trade can have important implications for both food security and the environmental impacts of production. Measurements of globalization and the environmental impacts of food production require data on both total trade and the origin and destination of traded goods (the network structure). While the global trade network of agricultural and livestock products has previously been studied, seafood products have been excluded. This study describes the structure and evolution of the global seafood trade network, including metrics quantifying the globalization of seafood, shifts in bilateral trade flows, changes in centrality and comparisons of seafood to agricultural and industrial trade networks. From 1994 to 2012 the number of countries trading in the network remained relatively constant, while the number of trade partnerships increased by over 65%. Over this same period, the total quantity of seafood traded increased by 58% and the value increased 85% in real terms. These changes signify the increasing globalization of seafood products. Additionally, the trade patterns in the network indicate: increased influence of Thailand and China, strengthened intraregional trade, and increased exports from South America and Asia. In addition to characterizing these network changes, this study identifies data needs in order to connect seafood trade with environmental impacts and food security outcomes.

  5. 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.

  6. 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)

  7. Thai Rhetorical Structure Analysis

    CERN Document Server

    Sinthupoun, Somnuk

    2010-01-01

    A rhetorical structure tree (RS tree) is a representation of discourse relations among elementary discourse units (EDUs). A RS tree is very useful to many text processing tasks employing relationships among EDUs such as text understanding, summarization, and question answering. Thai language with its unique linguistic characteristics requires a unique RS tree construction technique. This paper proposes an approach for Thai RS tree construction which consists of three major steps: EDU segmentation, Thai RS tree construction, and discourse relation (DR) identification. Two hidden markov models derived from grammatical rules are used to segment EDUs, a clustering technique with its similarity measure derived from Thai semantic rules is used to construct a Thai RS tree, and a decision tree whose features extracted from the rules is used to determine the DR between EDUs. The proposed technique is evaluated using three Thai corpora. The results show the Thai RS tree construction and the DR identification effectiven...

  8. Evolution of microwave ferromagnetic resonance with magnetic domain structure in FeCoBSi antidot arrays

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Peiheng, E-mail: phzhou@uestc.edu.cn; Zhang, Nan; Liu, Tao; Xie, Jianliang; Deng, Longjiang

    2014-08-01

    Magnetic domain structure of FeCoBSi antidot array thin films of varying thickness were characterized using surface magneto-optic Kerr effect. Vibrating sample magnetometry and microstrip transmission line measurements helped to associate the microwave magnetic analysis of the antidot arrays with hysteresis studies. The domain structure evolution from quasi-continuous domains to strip domains induced by the competing exchange and dipolar interaction resulted in the change of ferromagnetic resonance from multi-band to single-band. Hence, the mechanisms of multi-resonance are proposed to be related to domain wall motion, natural resonance and spin wave modes. This phenomenon can be used to control the magnetization dynamics in spin wave devices. - Highlights: • A multiresonance mechanism for ferromagnetic antidot array is proposed. • The mechanism relies on the domain structure evolution of antidote arrays. • Domain structure of antidot arrays changes from quasi-continuous patterns to strip domains. • Resonance of domain wall motion is discriminated from the natural resonance and spin wave modes.

  9. Process Analysis in Container Shipping Network Structure Form Change

    Directory of Open Access Journals (Sweden)

    Chen Chao

    2012-03-01

    Full Text Available Being aimed at the influence of ship-size and cargo-demand changes on container shipping networks, to reveal the evolution process of container shipping networks structure form, this paper respectively designed the operation models for two major container shipping networks structure forms: Multi-port-calling network and Hub-and-spoke network, to maximizing the investment efficiency. Based on the above models, a comprehensively integrated operation model of container shipping networks is built and the evolution process of container shipping networks structure form with changing of both ship-size and cargo demands is analyzed. Finally, through a case study, results show that the comprehensive integrated operation model is very effective in the analysis of evolution process of container shipping networks structure forms.

  10. Spectral properties of the temporal evolution of brain network structure

    Science.gov (United States)

    Wang, Rong; Zhang, Zhen-Zhen; Ma, Jun; Yang, Yong; Lin, Pan; Wu, Ying

    2015-12-01

    The temporal evolution properties of the brain network are crucial for complex brain processes. In this paper, we investigate the differences in the dynamic brain network during resting and visual stimulation states in a task-positive subnetwork, task-negative subnetwork, and whole-brain network. The dynamic brain network is first constructed from human functional magnetic resonance imaging data based on the sliding window method, and then the eigenvalues corresponding to the network are calculated. We use eigenvalue analysis to analyze the global properties of eigenvalues and the random matrix theory (RMT) method to measure the local properties. For global properties, the shifting of the eigenvalue distribution and the decrease in the largest eigenvalue are linked to visual stimulation in all networks. For local properties, the short-range correlation in eigenvalues as measured by the nearest neighbor spacing distribution is not always sensitive to visual stimulation. However, the long-range correlation in eigenvalues as evaluated by spectral rigidity and number variance not only predicts the universal behavior of the dynamic brain network but also suggests non-consistent changes in different networks. These results demonstrate that the dynamic brain network is more random for the task-positive subnetwork and whole-brain network under visual stimulation but is more regular for the task-negative subnetwork. Our findings provide deeper insight into the importance of spectral properties in the functional brain network, especially the incomparable role of RMT in revealing the intrinsic properties of complex systems.

  11. Study on the Evolution Mechanism and Development Forecasting of China’s Power Supply Structure Clean Development

    Directory of Open Access Journals (Sweden)

    Xiaohua Song

    2017-02-01

    Full Text Available The clean development of China’s power supply structure has become a crucial strategic problem for the low-carbon, green development of Chinese society. Considering the subsistent developments of optimized allocation of energy resources and efficient utilization, the urgent need to solve environmental pollution, and the continuously promoted power market-oriented reform, further study of China’s power structure clean development has certain theoretical value. Based on the data analysis, this paper analyzes the key factors that influence the evolution process of the structure with the help of system dynamics theory and carries out comprehensive assessments after the construction of the structure evaluation system. Additionally, a forecasting model of the power supply structure development based on the Vector Autoregressive Model (VAR has been put forward to forecast the future structure. Through the research of policy review and scenario analysis, the paths and directions of structure optimization are proposed. In this paper, the system dynamics, vector autoregressive model (VAR, policy mining, and scenario analysis methods are combined to systematically demonstrate the evolution of China’s power structure, and predict the future direction of development. This research may provide a methodological and practical reference for the analysis of China’s power supply structure optimization development and for theoretical studies.

  12. STRUCTURAL EVOLUTION AND COMPOSITION CHANGE IN THE SURFACE REGION OF POLYPROPYLENE/CLAY NANOCOMPOSITES ANNEALED AT HIGH TEMPERATURES

    Institute of Scientific and Technical Information of China (English)

    唐涛

    2009-01-01

    A model experiment was done to clear the formation mechanism of protective layers during combustion of polypropylene(PP)/organically modified montmorillonite(OMMT) nanocomposites.The investigation was focused on the effects of annealing temperature on the structural changes and protective layer formation.The decomposition of OMMT and degradation of PP/OMMT nanocomposites were characterized by means of thermogravimetric analysis(TGA).The structural evolution and composition change in the surface region of...

  13. 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.

  14. 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.

  15. Myosin MyTH4-FERM structures highlight important principles of convergent evolution.

    Science.gov (United States)

    Planelles-Herrero, Vicente José; Blanc, Florian; Sirigu, Serena; Sirkia, Helena; Clause, Jeffrey; Sourigues, Yannick; Johnsrud, Daniel O; Amigues, Beatrice; Cecchini, Marco; Gilbert, Susan P; Houdusse, Anne; Titus, Margaret A

    2016-05-24

    Myosins containing MyTH4-FERM (myosin tail homology 4-band 4.1, ezrin, radixin, moesin, or MF) domains in their tails are found in a wide range of phylogenetically divergent organisms, such as humans and the social amoeba Dictyostelium (Dd). Interestingly, evolutionarily distant MF myosins have similar roles in the extension of actin-filled membrane protrusions such as filopodia and bind to microtubules (MT), suggesting that the core functions of these MF myosins have been highly conserved over evolution. The structures of two DdMyo7 signature MF domains have been determined and comparison with mammalian MF structures reveals that characteristic features of MF domains are conserved. However, across millions of years of evolution conserved class-specific insertions are seen to alter the surfaces and the orientation of subdomains with respect to each other, likely resulting in new sites for binding partners. The MyTH4 domains of Myo10 and DdMyo7 bind to MT with micromolar affinity but, surprisingly, their MT binding sites are on opposite surfaces of the MyTH4 domain. The structural analysis in combination with comparison of diverse MF myosin sequences provides evidence that myosin tail domain features can be maintained without strict conservation of motifs. The results illustrate how tuning of existing features can give rise to new structures while preserving the general properties necessary for myosin tails. Thus, tinkering with the MF domain enables it to serve as a multifunctional platform for cooperative recruitment of various partners, allowing common properties such as autoinhibition of the motor and microtubule binding to arise through convergent evolution.

  16. Structure and evolution of high-mass stellar mergers

    CERN Document Server

    Glebbeek, Evert; Zwart, Simon Portegies; Pols, Onno R

    2013-01-01

    In young dense clusters repeated collisions between massive stars may lead to the formation of a very massive star (above 100 Msun). In the past the study of the long-term evolution of merger remnants has mostly focussed on collisions between low-mass stars (up to about 2 Msun) in the context of blue-straggler formation. The evolution of collision products of more massive stars has not been as thoroughly investigated. In this paper we study the long-term evolution of a number of stellar mergers formed by the head-on collision of a primary star with a mass of 5-40 Msun with a lower mass star at three points in its evolution in order to better understand their evolution. We use smooth particle hydrodynamics (SPH) calculations to model the collision between the stars. The outcome of this calculation is reduced to one dimension and imported into a stellar evolution code. We follow the subsequent evolution of the collision product through the main sequence at least until the onset of helium burning. We find that l...

  17. Statistical characteristics of formation and evolution of structure in the universe

    CERN Document Server

    Demianski, M

    1999-01-01

    An approximate statistical description of the formation and evolution of structure of the universe based on the Zel'dovich theory of gravitational instability is proposed. It is found that the evolution of DM structure shows features of self-similarity and the main structure characteristics can be expressed through the parameters of initial power spectrum and cosmological model. For the CDM-like power spectrum and suitable parameters of the cosmological model the effective matter compression reaches the observed scales $R_{wall}\\sim $20 -- 25$h^{-1}$Mpc with the typical mean separation of wall-like elements $D_{SLSS}\\sim $50 -- 70$h^{-1}$Mpc. This description can be directly applied to the deep pencil beam galactic surveys and absorption spectra of quasars. For larger 3D catalogs and simulations it can be applied to results obtained with the core-sampling analysis. It is shown that the interaction of large and small scale perturbations modulates the creation rate of early Zel'dovich pancakes and generates bia...

  18. Evolution analysis of the states of the EZ model

    Institute of Scientific and Technical Information of China (English)

    Chen Qing-Hua; Ding Yi-Ming; Dong Hong-Guang

    2009-01-01

    Based on suitable choice of states,this paper studies the stability of the equilibrium state of the EZ model by regarding the evolution of the EZ model as a Markov chain and by showing that the Markov chain is ergodic.The Markov analysis is applied to the EZ model with small number of agents,the exact equilibrium state for N=5 and numerical results for N=18 are obtained.

  19. Graph spectral analysis of protein interaction network evolution

    OpenAIRE

    Thorne, Thomas; Stumpf, Michael P. H.

    2012-01-01

    We present an analysis of protein interaction network data via the comparison of models of network evolution to the observed data. We take a Bayesian approach and perform posterior density estimation using an approximate Bayesian computation with sequential Monte Carlo method. Our approach allows us to perform model selection over a selection of potential network growth models. The methodology we apply uses a distance defined in terms of graph spectra which captures the network data more natu...

  20. 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

  1. Statistical characteristics of formation and evolution of structure in the universe

    OpenAIRE

    Demianski, M.; Doroshkevich, A.

    1999-01-01

    An approximate statistical description of the formation and evolution of structure of the universe based on the Zel'dovich theory of gravitational instability is proposed. It is found that the evolution of DM structure shows features of self-similarity and the main structure characteristics can be expressed through the parameters of initial power spectrum and cosmological model. For the CDM-like power spectrum and suitable parameters of the cosmological model the effective matter compression ...

  2. InterEvol database: exploring the structure and evolution of protein complex interfaces

    OpenAIRE

    Faure, Guilhem; Andreani, Jessica; Guerois, Raphaël

    2011-01-01

    Capturing how the structures of interacting partners evolved at their binding interfaces is a fundamental issue for understanding interactomes evolution. In that scope, the InterEvol database was designed for exploring 3D structures of homologous interfaces of protein complexes. For every chain forming a complex in the protein data bank (PDB), close and remote structural interologs were identified providing essential snapshots for studying interfaces evolution. The database provides tools to ...

  3. Probability Density Evolution Analysis for Stochastic Dynamic Seismic Responses of Structures Based on Improved Point Estimation Method%基于改进点估计法的结构随机动力地震反应概率密度演化

    Institute of Scientific and Technical Information of China (English)

    宋鹏彦; 吕大刚; 于晓辉; 王光远

    2014-01-01

    为了获得结构反应概率密度随时间的变化规律,将改进的点估计法、最大熵原理与随机动力学的概率密度演化理论相结合,提出了基于统计矩信息的结构非线性随机动力反应概率密度演化分析方法。以一栋按我国规范设计的钢筋混凝土框架结构为研究对象,选取结构在地震作用下的顶层位移和整体地震损伤指数作为反应参数,并考虑结构参数的不确定性,用本文提出的方法进行了地震作用下结构的非线性随机动力反应的概率密度演化分析及参数灵敏度分析,结果表明:钢筋屈服强度、结构的阻尼、混凝土容重对结构的位移反应影响较为明显,灵敏度超过10%。%In order to obtain the law of probability densities of structural responses varying with time, a new moment-based approach for analysis of probability density evolution of nonlinear stochastic dynamic responses of structures was developed,by combining an improved point estimation method (IPEM)with the maximum entropy theory and the probability density evolution theory for stochastic dynamics of structures. The proposed method was then used to perform probabilistic density evolution analysis and parameter sensitivity analysis of a reinforced concrete (RC ) frame structure designed according to Chinese codes,selecting the top displacement and global seismic damage index of the structure under earthquake as response parameters,and taking into account the uncertainty of structural parameters. The results show that the steel yield strength,the structural damping ratio,and concrete gravity density have dominant influences on structural displacement,with a sensitivity of more than 10%.

  4. Analysis of the Structuration Evolution Mechanism of Inter-firm Collaborative Knowledge Creation%企业间合作知识创造的结构化演变机理研究

    Institute of Scientific and Technical Information of China (English)

    韩晓琳; 张庆普; 单伟

    2012-01-01

    深入理解合作知识创造机理有助于构建有效的合作知识创造管理模式,促进企业间的合作知识创造进程.可是,由于合作企业在战略规划、利益机制、企业文化和管理模式等方面存在差异,合作知识创造的机理非常复杂.在阐明结构化理论和合作知识创造理论一致性的基础上,应用结构二重性原理,从合作博弈、表意结构、支配结构和合法化结构四个维度对企业间合作知识创造的结构化演变机理进行了剖析,并构建了基于结构化模态的合作知识创造管理模式,以有效提高企业间合作知识创造绩效.%Mastering collaborative knowledge creation mechanism can contribute to constructing effective collaborative knowledge creation management mode, and promoting inter- firm collaborative knowledge creation process. However, because of the differences of inter-firm in strategic planning, interest mechanism, corporate culture and management mode, collaborative knowledge creation mechanism is very complex. On the basis of clarifying the consistency between structuration theory and collaborative knowledge creation theory, this paper analyzes the structuration evolution mechanism of inter-firm collaborative knowledge creation from four dimensions: collaborative game, signification, domination, and legitimation. Based on the structuration mode, the paper constructs the collaborative knowledge creation management mode to improve the inter-firm collaborative knowledge creation performance.

  5. 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.

  6. Is it possible to unify the QCD evolution of structure functions in X and $Q^{2}$?

    CERN Document Server

    Peschanski, R

    1995-01-01

    We start from the two existing QCD evolution equations for structure functions, the BFKL and DGLAP equations, and discuss the theoretical hints for a unifying picture of the evolution in x and Q^2. The main difficulty is due to the property of angular ordering of the gluon radiation driving the evolution and the cancellation of the related collinear singularities. At the leading \\log\\ 1/x and leading \\log \\ Q^2 accuracy, we find a unified set of equations satisfying the constraints.

  7. Compensatory evolution of a precursor messenger RNA secondary structure in the Drosophila melanogaster Adh gene

    Science.gov (United States)

    Chen, Ying; Stephan, Wolfgang

    2003-01-01

    Evidence for the evolutionary maintenance of a hairpin structure possibly involved in intron processing had been found in intron 1 of the alcohol dehydrogenase gene (Adh) in diverse Drosophila species. In this study, the putative hairpin structure was evaluated systematically in Drosophila melanogaster by elimination of either side of the stem using site-directed mutagenesis. The effects of these mutations and the compensatory double mutant on intron splicing efficiency and ADH protein production were assayed in Drosophila melanogaster Schneider L2 cells and germ-line transformed adult flies. Mutations that disrupt the putative hairpin structure right upstream of the intron branch point were found to cause a significant reduction in both splicing efficiency and ADH protein production. In contrast, the compensatory double mutant that restores the putative hairpin structure was indistinguishable from the WT in both splicing efficiency and ADH level. It was also observed by mutational analysis that a more stable secondary structure (with a longer stem) in this intron decreases both splicing efficiency and ADH protein production. Implications for RNA secondary structure and intron evolution are discussed. PMID:12972637

  8. 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

    . These structures have in the last decades been an integrated part of the discussions about subsidence and uplift of not only the interior of the basin but also of the basin margin. Abundant 2D and 3D seismic data and new depositional models enable detailed analysis and reinterpretation of where and when basement......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......). Furthermore, prograding Oligocene and Miocene units in combination with thermal and loading induced differential subsidence between the basins and the Ringkøbing-Fyn High controlled the Cenozoic reactivations of the main coverfaults. The detaching cover faults generated additional accommodation space, which...

  9. Compact structure and proteins of pasta retard in vitro digestive evolution of branched starch molecular structure.

    Science.gov (United States)

    Zou, Wei; Sissons, Mike; Warren, Frederick J; Gidley, Michael J; Gilbert, Robert G

    2016-11-01

    The roles that the compact structure and proteins in pasta play in retarding evolution of starch molecular structure during in vitro digestion are explored, using four types of cooked samples: whole pasta, pasta powder, semolina (with proteins) and extracted starch without proteins. These were subjected to in vitro digestion with porcine α-amylase, collecting samples at different times and characterizing the weight distribution of branched starch molecules using size-exclusion chromatography. Measurement of α-amylase activity showed that a protein (or proteins) from semolina or pasta powder interacted with α-amylase, causing reduced enzymatic activity and retarding digestion of branched starch molecules with hydrodynamic radius (Rh)pasta protects the starch and proteins in the interior of the whole pasta, reducing the enzymatic degradation of starch molecules, especially for molecules with Rh>100nm.

  10. Models of the Protocellular Structures, Functions and Evolution

    Science.gov (United States)

    Pohorille, Andrew; New, Michael; Keefe, Anthony; Szostak, Jack W.; Lanyi, Janos F.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    In the absence of extinct or extant record of protocells, the most direct way to test our understanding of the origin of cellular life is to construct laboratory models that capture important features of protocellular systems. Such efforts are currently underway in a collaborative project between NASA-Ames, Harvard medical School and University of California. They are accompanied by computational studies aimed at explaining self-organization of simple molecules into ordered structures. The centerpiece of this project is a method for the in vitro evolution of protein enzymes toward arbitrary catalytic targets. A similar approach has already been developed for nucleic acids: First, a very large population of candidate molecules is generated using a random synthetic approach. Next, the small numbers of molecules that can accomplish the desired task are selected. These molecules are next vastly multiplied using the polymerase chain reaction. A mutagenic approach, in which the sequences of selected molecules are randomly altered, can yield further improvements in performance or alterations of specificities. Unfortunately, the catalytic potential of nucleic acids is rather limited. Proteins are more catalytically capable but cannot be directly amplified. In the new technique, this problem is circumvented by covalently linking each protein of the initial, diverse, pool to the RNA sequence that codes for it. Then, selection is performed on the proteins, but the nucleic acids are replicated. To date, we have obtained "a proof of concept" by evolving simple, novel proteins capable of selectively binding adenosine tri-phosphate (ATP). Our next goal is to create an enzyme that can phosphorylate amino acids and another to catalyze the formation of peptide bonds in the absence of nucleic acid templates. This latter reaction does not take place in contemporary cells. once developed, these enzymes will be encapsulated in liposomes so that they will function in a simulated cellular

  11. Evolution of dislocation structures following a change in loading conditions studied by in situ high resolution reciprocal space mapping

    DEFF Research Database (Denmark)

    Wejdemann, Christian

    corresponding to the contributions from the subgrains and the walls. The analysis showed that the morphology of the dislocation structures is almost unchanged during the micro-plastic range of the in situ deformation, and during the macroplastic range the evolution occurs in a gradual manner without any sudden......-granular stresses are substantially redistributed during the micro-plastic range. In a few individual subgrains it was possible to follow the evolution of the elastic back-strain from the tensile to the compressive case. Following an increase in temperature from -196 ○C to room temperature, both the average intra...

  12. Evolution and Structure of Neuromuscular Systems in Spiralian Meiofauna

    DEFF Research Database (Denmark)

    Bekkouche, Nicolas Tarik

    into their evolution: Lobatocerebrum is an aberrant annelid showing only few common traits with Annelida, yet, our detailed studies unravel putative resemblances of muscular, nervous and glandular system to previous findings in annelids. Micrognathozoa shows more resemblances with Rotifera than Gnathostomulida (these...... on the evolution of this group. Diuronotus aspetos shows a unique combination of muscular traits not easily traceable, but in contrast the nervous system traits can be compared in high details, hereby bridging to other Chaetonotida (Gastrotricha). Moreover, we describe new gastrotrich characters...... 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...

  13. Structure and evolution of the Y-chromosomal and mitochondrial DNA of cattle

    NARCIS (Netherlands)

    Verkaar, Edward Louis Christian

    2004-01-01

    The research described in this thesis is focused on the structure and evolution of the bovine Y-chromosome and the use of paternal markers in molecular diagnostics. The Y-chromosome has emerged together with the X-chromosome early during the evolution of the mammals by differentiation of a pair of a

  14. 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…

  15. Modeling solidification structure evolution and microsegregation under pressure condition

    Institute of Scientific and Technical Information of China (English)

    Qiang Li; Qiaoyi Guo; Rongde Li

    2006-01-01

    Solidification microstructure and microsegregation were simulated under a constant pressure condition using the cellular automaton method. First, a single dendrite evolution was simulated and compared under pressure condition and under normal condition,respectively. The solidification microstructure and microsegregation were then simulated. Through simulation, it may be concluded that if the growth direction of the dendrite is parallel to the pressure direction, dendrite growth will be hindered. On the other hand,pressure has no influence on the dendrite evolution. However, when two dendrites grow in close contact, solute enrichment occurs in the dendrites, which hinders the growth of the dendrites. In addition, the solute is preferentially enriched along the pressure direction.

  16. Kinematic and Structural Evolution of Field and Cluster Spiral Galaxies

    CERN Document Server

    Ziegler, Bodo L; Da Rocha, Cristiano; Böhm, Asmus; Peletier, Reynier F; Verdugo, Miguel

    2009-01-01

    To understand the processes that build up galaxies we investigate the stellar structure and gas kinematics of spiral and irregular galaxies out to redshift 1. We target 92 galaxies in four cluster (z = 0.3 & 0.5) fields to study the environmental influence. Their stellar masses derived from multiband VLT/FORS photometry are distributed around but mostly below the characteristic Schechter-fit mass. From HST/ACS images we determine morphologies and structural parameters like disk length, position angle and ellipticity. Combining the spectra of three slit positions per galaxy using the MXU mode of VLT/FORS2 we construct the two-dimensional velocity field from gas emission lines for 16 cluster members and 33 field galaxies. The kinematic position angle and flatness are derived by a Fourier expansion of elliptical velocity profiles. To trace possible interaction processes, we define three irregularity indicators based on an identical analysis of local galaxies from the SINGS project. Our distant sample display...

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

    Science.gov (United States)

    Chicote, Javier U.; DeSalle, Rob; García-España, Antonio

    2017-01-01

    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. PMID:28257417

  18. The Evolution and Internal Structure of Jupiter and Saturn with Compositional Gradients

    CERN Document Server

    Vazan, A; Podolak, M; Kovetz, A

    2016-01-01

    The internal structure of gas giant planets may be more complex than the commonly assumed core-envelope structure with an adiabatic temperature profile. Different primordial internal structures as well as various physical processes can lead to non-homogenous compositional distributions. A non-homogenous internal structure has a significant impact on the thermal evolution and final structure of the planets. In this paper, we present alternative structure and evolution models for Jupiter and Saturn allowing for non-adiabatic primordial structures and the mixing of heavy elements by convection as these planets evolve. We present the evolution of the planets accounting for various initial composition gradients, and in the case of Saturn, include the formation of a helium-rich region as a result of helium rain. We investigate the stability of regions with composition gradients against convection, and find that the helium shell in Saturn remains stable and does not mix with the rest of the envelope. In other cases,...

  19. Parallel dynamics and evolution: Protein conformational fluctuations and assembly reflect evolutionary changes in sequence and structure.

    Science.gov (United States)

    Marsh, Joseph A; Teichmann, Sarah A

    2014-02-01

    Protein structure is dynamic: the intrinsic flexibility of polypeptides facilitates a range of conformational fluctuations, and individual protein chains can assemble into complexes. Proteins are also dynamic in evolution: significant variations in secondary, tertiary and quaternary structure can be observed among divergent members of a protein family. Recent work has highlighted intriguing similarities between these structural and evolutionary dynamics occurring at various levels. Here we review evidence showing how evolutionary changes in protein sequence and structure are often closely related to local protein flexibility and disorder, large-scale motions and quaternary structure assembly. We suggest that these correspondences can be largely explained by neutral evolution, while deviations between structural and evolutionary dynamics can provide valuable functional insights. Finally, we address future prospects for the field and practical applications that arise from a deeper understanding of the intimate relationship between protein structure, dynamics, function and evolution.

  20. Evolutions of fluctuation modes and inner structures of global stock markets

    Science.gov (United States)

    Yan, Yan; Wang, Lei; Liu, Maoxin; Chen, Xiaosong

    2016-09-01

    The paper uses empirical data, including 42 globally main stock indices in the period 1996-2014, to systematically study the evolution of fluctuation modes and inner structures of global stock markets. The data are large in scale considering both time and space. A covariance matrix-based principle fluctuation mode analysis (PFMA) is used to explore the properties of the global stock markets. It has been ignored by previous studies that covariance matrix is more suitable than the correlation matrix to be the basis of PFMA. It is found that the principle fluctuation modes of global stock markets are in the same directions, and global stock markets are divided into three clusters, which are found to be closely related to the countries’ locations with exceptions of China, Russia and Czech Republic. A time-stable correlation network constructing method is proposed to solve the problem of high-level statistical uncertainty when the estimated periods are very short, and the complex dynamic network (CDN) is constructed to investigate the evolution of inner structures. The results show when the clusters emerge and how long the clusters exist. When the 2008 financial crisis broke out, the indices form one cluster. After these crises, only the European cluster still exists. These findings complement the previous studies, and can help investors and regulators to understand the global stock markets.

  1. 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 met

  2. Properties and evolution of anisotropic structures in collisionless plasmas

    CERN Document Server

    Karimov, A R; Stenflo, L

    2016-01-01

    A new class of exact electrostatic solutions of the Vlasov-Maxwell equations based on the Jeans's theorem is proposed for studying the evolution and properties of two-dimensional anisotropic plasmas that are far from thermodynamic equilibrium. In particular, the free expansion of a slab of electron-ion plasma into vacuum is investigated.

  3. 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 met

  4. Downstream Evolution of Longitudinal Embedded Vortices with Helical Structure

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Okulov, Valery; Hansen, Martin Otto Laver

    2009-01-01

    In the present work the downstream development of device induced vortices with helical symmetry embedded in wall bounded flow on a bump is studied with the aid of Stereoscopic Particle Image Velocimetry (SPIV). The downstream evolution of characteristic parameters of helical vortices is studied...

  5. China’s Structural Energy Conservation: Analysis and Proposals

    Institute of Scientific and Technical Information of China (English)

    张雷; 黄园淅

    2008-01-01

    Given the increasing dependence of development on energy consumption, an understanding of the rules and trends of national energy consumption is required for boosting social energy conservation. By using two models -- the structural evolution energy consumption model and the structural evolution per-unit energy consumption model, this article attempts to make an international comparison of the industrial structure development versus energy consumption patterns in the United States, the United Kingdom, France, Germany, Japan, and India. The results of this analysis indicate that the dominance of secondary industry over the industrial structure evolution process noticeably accelerates national energy consumption at the initial stage of modernization. Subsequently, a slowdown in energy consumption as a result of industrial structure development yields effects as the diversification process speeds up. Under such influence, energy consumption per unit of GDP follows an inverted U-shaped curve from rise to decline. As one of the world’s major energy producers and consumers, China has long employed a one- sided sector development policy. Under the influence of this policy, national energy conservation endeavors have been inhibited by the rigidity in its industry structural evolution. Thus, in China, energy consumption per unit of GDP has remained at a high level.

  6. Generalized Dromion Structures of New (2 + 1)-Dimensional Nonlinear EvolutionEquation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie-Fang

    2001-01-01

    We derive the generalized dromions of the new (2 + 1)-dimensional nonlinear evolution equation by the arbitrary function presented in the bilinearized linear equations. The rich soliton and dromion structures for this system are released.

  7. Structural evolution of Ti50Cu50 on rapid cooling by molecular dynamics simulation

    Science.gov (United States)

    Pang, J. J.; Tan, M. J.; Liew, K. M.

    2012-03-01

    The structural evolution and atomic structure of the Ti50Cu50 compound have been investigated by means of molecular dynamics simulation using the generalized embedded-atom model (GEAM) potential. Gibbs free energy calculation manifests the large driving force of undercooled Ti50Cu50 for crystallization and thus the poor glass-forming ability. Radial distribution functions (RDFs) within the temperature range from 2000 K to 300 K are analyzed and reveal the increasing degree of short-range order and reducing periodic length between peaks on cooling. Atomic arrangement is characterized by the Voronoi tessellation method, showing that the frequency of icosahedral configurations is most sensitive to temperature and grows upon quenching while that of the others remains relatively stable. The thermal behavior of the structure factors follows the Debye model up to the supercooled liquid temperature. The structural investigation of amorphous Ti50Cu50 demonstrates that there exist a variety of polyhedral configurations in Ti50Cu50 amorphous alloy, where icosahedral and bcc clusters are the major types. Due to the existence of bcc clusters and the other distorted polyhedra other than full icosahedra, the structural analysis reconfirms the inference from the Gibbs free energy calculation.

  8. The concurrent evolution of cooperation and the population structures that support it.

    Science.gov (United States)

    Powers, Simon T; Penn, Alexandra S; Watson, Richard A

    2011-06-01

    The evolution of cooperation often depends upon population structure, yet nearly all models of cooperation implicitly assume that this structure remains static. This is a simplifying assumption, because most organisms possess genetic traits that affect their population structure to some degree. These traits, such as a group size preference, affect the relatedness of interacting individuals and hence the opportunity for kin or group selection. We argue that models that do not explicitly consider their evolution cannot provide a satisfactory account of the origin of cooperation, because they cannot explain how the prerequisite population structures arise. Here, we consider the concurrent evolution of genetic traits that affect population structure, with those that affect social behavior. We show that not only does population structure drive social evolution, as in previous models, but that the opportunity for cooperation can in turn drive the creation of population structures that support it. This occurs through the generation of linkage disequilibrium between socio-behavioral and population-structuring traits, such that direct kin selection on social behavior creates indirect selection pressure on population structure. We illustrate our argument with a model of the concurrent evolution of group size preference and social behavior.

  9. 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...... for determination of the structures pre-stresses is used. A parametric investigation is performed to determine a more optimized form of the plate based tensegrity structure. Conclusions of the use of plate based tensegrity in civil engineering and further research areas are discussed....

  10. 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).

  11. Alpha-synuclein gene structure,evolution,and protein aggregation

    Institute of Scientific and Technical Information of China (English)

    Lili Xiong; Peng Zhao; Zhiyun Guo; Jianhua Zhang; Diqiang Li; Canquan Mao

    2010-01-01

    α-synuclein,a member of the synuclein family,is predominately expressed in brain tissues,where it is the major component of Lewy bodies,the major hallmark of Parkinson's disease.We analyzed the phylogenetics,gene structure,and effects of different forms of α-synuclein on in vitro protein aggregation.The synuclein phylogenetic tree showed that sequences could be classified into α,β,and γ protein groups.The orthologous gene α-,β-and γ-synuclein showed similar evolutionary distance to the paralogous gene α-,β-and γ-synuclein.Bioinformatics analysis suggests that the amino-acid sequence of human α-synuclein can be divided into three regions: N-terminal amphipathic region(1-60),central hydrophobic non-amyloid beta component segment(61-95),and the C-terminal acidic part(96-140).The mutant site of A30P is at the second exon of α-synuclein,whereas E46K is located at the third exon of α-synuclein.α-synuclein alternative splicing results in four isomers,and five exons,all of which participate in protein coding,comprising 140 amino acids to produce the major α-synuclein in vivo.The threeα-synuclein isoforms are products of alternative splicing,α-synuclein 126,112 and 98.We also review the genetic and cellular factors that affect the aggregation of α-synuclein and compounds that inhibit aggregation.A better understanding of α-synuclein sequences,structure,and function may allow better targeted therapy and diagnosis of α-synuclein in Parkinson's disease and other neurodegenerative diseases.

  12. 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,

  13. Marine Structural Analysis and Design

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    王迎光编上海交通大学出版社出版定价:$68.00内容简介:The material in this book has been continuously developed since the author started to teach Modern Ship Structural Design in the Department of Naval Architecture and Ocean Engineering of Shanghai Jiao Tong University in 2004.The subject of marine structural analysis and design is so broad that it is not possible to incorporate every aspect of this sub-

  14. Examination of Hurricane Sandy's (2012 structure and intensity evolution from full-field and anomaly-field analyses

    Directory of Open Access Journals (Sweden)

    Wei-Hong Qian

    2016-08-01

    Full Text Available An anomaly-based field analysis approach and a set of simple beta-advection models (BAMs have been used to examine the structure evolution and unusual left turn of Hurricane Sandy (2012 before it made the landfall and caused severe damage along the eastern US coast. Results show that the anomaly-based analysis approach can clearly reveal Sandy's structure evolution, including its interaction with other synoptic-scale systems as well as the intensification and extratropical transition (ET processes. During its lifetime, Sandy experienced two consecutive periods of intensification caused by the merging of anomalous vortices on 27 and 29 October. The unusual left turn and the ET process prior to the landfall are respectively influenced by an anomalous anticyclone to the northeast and an anomalous cold vortex at the 300–850 hPa layer to the northwest, which is confirmed by the experiments using the generalised BAM.

  15. The structural evolution process and the electronic properties of armchair silicon nanotubes

    Science.gov (United States)

    Liu, Deng-Hui; Tang, Yu-Chao; Yao, Cheng-Peng; Zhu, Heng-Jiang

    2016-04-01

    The structural evolution process of the capped armchair single- and double-walled SiNTs grown from silicon clusters was investigated using the DFT method. The evolution process was described quantitatively by monitoring change of the geometry structures. The initial structural configuration of the single- and double-walled SiNTs was determined by optimizing structure of the small silicon clusters. The evolution process of the SWSiNTs is through forming tubular clusters with a global reconstruction from structure of the double-rings. Then, it elongates through the layer-by-layer growth process with local reconstructions. Eventually, the infinite SiNTs can be constructed with corresponding repeat unit, designed by the periodic characteristics on the basis of tubular clusters. Eventually, All of the SiNTs have a narrow band gap. From calculation of band structure, the band gap which occurs oscillations and gradually decreases with increase of the diameter, length, and the number of walls.

  16. Evolution of collective action in adaptive social structures.

    Science.gov (United States)

    Moreira, João A; Pacheco, Jorge M; Santos, Francisco C

    2013-01-01

    Many problems in nature can be conveniently framed as a problem of evolution of collective cooperative behaviour, often modelled resorting to the tools of evolutionary game theory in well-mixed populations, combined with an appropriate N-person dilemma. Yet, the well-mixed assumption fails to describe the population dynamics whenever individuals have a say in deciding which groups they will participate. Here we propose a simple model in which dynamical group formation is described as a result of a topological evolution of a social network of interactions. We show analytically how evolutionary dynamics under public goods games in finite adaptive networks can be effectively transformed into a N-Person dilemma involving both coordination and co-existence. Such dynamics would be impossible to foresee from more conventional 2-person interactions as well as from descriptions based on infinite, well-mixed populations. Finally, we show how stochastic effects help rendering cooperation viable, promoting polymorphic configurations in which cooperators prevail.

  17. 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...

  18. 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 ...

  19. The structure of mutations and the evolution of cooperation.

    Directory of Open Access Journals (Sweden)

    Julián García

    Full Text Available Evolutionary game dynamics in finite populations assumes that all mutations are equally likely, i.e., if there are n strategies a single mutation can result in any strategy with probability 1/n. However, in biological systems it seems natural that not all mutations can arise from a given state. Certain mutations may be far away, or even be unreachable given the current composition of an evolving population. These distances between strategies (or genotypes define a topology of mutations that so far has been neglected in evolutionary game theory. In this paper we re-evaluate classic results in the evolution of cooperation departing from the assumption of uniform mutations. We examine two cases: the evolution of reciprocal strategies in a repeated prisoner's dilemma, and the evolution of altruistic punishment in a public goods game. In both cases, alternative but reasonable mutation kernels shift known results in the direction of less cooperation. We therefore show that assuming uniform mutations has a substantial impact on the fate of an evolving population. Our results call for a reassessment of the "model-less" approach to mutations in evolutionary dynamics.

  20. Principal Component Analysis reveals correlation of cavities evolution and functional motions in proteins.

    Science.gov (United States)

    Desdouits, Nathan; Nilges, Michael; Blondel, Arnaud

    2015-02-01

    Protein conformation has been recognized as the key feature determining biological function, as it determines the position of the essential groups specifically interacting with substrates. Hence, the shape of the cavities or grooves at the protein surface appears to drive those functions. However, only a few studies describe the geometrical evolution of protein cavities during molecular dynamics simulations (MD), usually with a crude representation. To unveil the dynamics of cavity geometry evolution, we developed an approach combining cavity detection and Principal Component Analysis (PCA). This approach was applied to four systems subjected to MD (lysozyme, sperm whale myoglobin, Dengue envelope protein and EF-CaM complex). PCA on cavities allows us to perform efficient analysis and classification of the geometry diversity explored by a cavity. Additionally, it reveals correlations between the evolutions of the cavities and structures, and can even suggest how to modify the protein conformation to induce a given cavity geometry. It also helps to perform fast and consensual clustering of conformations according to cavity geometry. Finally, using this approach, we show that both carbon monoxide (CO) location and transfer among the different xenon sites of myoglobin are correlated with few cavity evolution modes of high amplitude. This correlation illustrates the link between ligand diffusion and the dynamic network of internal cavities.

  1. Identification of structure and parameters of rheological constitutive model for rocks using differential evolution algorithm

    Institute of Scientific and Technical Information of China (English)

    苏国韶; 张小飞; 陈光强; 符兴义

    2008-01-01

    To determine structure and parameters of a rheological constitutive model for rocks,a new method based on differential evolution(DE) algorithm combined with FLAC3D(a numerical code for geotechnical engineering) was proposed for identification of the global optimum coupled of model structure and its parameters.At first,stochastic coupled mode was initialized,the difference in displacement between the numerical value and in-situ measurements was regarded as fitness value to evaluate quality of the coupled mode.Then the coupled-mode was updated continually using DE rule until the optimal parameters were found.Thus,coupled-mode was identified adaptively during back analysis process.The results of applications to Jinping tunnels in China show that the method is feasible and efficient for identifying the coupled-mode of constitutive structure and its parameters.The method overcomes the limitation of the traditional method and improves significantly precision and speed of displacement back analysis process.

  2. Space-time isogeometric analysis of parabolic evolution problems

    Science.gov (United States)

    Langer, Ulrich; Moore, Stephen E.; Neumüller, Martin

    2016-07-01

    We present and analyze a new stable space-time Isogeometric Analysis (IgA) method for the numerical solution of parabolic evolution equations in fixed and moving spatial computational domains. The discrete bilinear form is elliptic on the IgA space with respect to a discrete energy norm. This property together with a corresponding boundedness property, consistency and approximation results for the IgA spaces yields an a priori discretization error estimate with respect to the discrete norm. The theoretical results are confirmed by several numerical experiments with low- and high-order IgA spaces.

  3. MICROMECHANICS ANALYSIS ON EVOLUTION OF CRACK IN VISCOELASTIC MATERIALS

    Institute of Scientific and Technical Information of China (English)

    张双寅

    2002-01-01

    A preliminary analysis on crack evolution in viscoelastic materials was presented Based on the equivalent inclusion concept of micro mechanics theory, the explicit expressions of crack opening displacement δ and energy release rate G were derived,indicating that both δ and G are increasing with time. The equivalent modulus of the viscoelastic solid comprising cracks was evaluated. It is proved that the decrease of the modulus comes from two mechanisms: one is the viscoelasticity of the material; the other is the crack opening which is getting larger with time.

  4. Moving shape analysis and control applications to fluid structure interactions

    CERN Document Server

    Moubachir, Marwan

    2006-01-01

    Problems involving the evolution of two- and three-dimensional domains arise in many areas of science and engineering. Emphasizing an Eulerian approach, Moving Shape Analysis and Control: Applications to Fluid Structure Interactions presents valuable tools for the mathematical analysis of evolving domains. The book illustrates the efficiency of the tools presented through different examples connected to the analysis of noncylindrical partial differential equations (PDEs), such as Navier-Stokes equations for incompressible fluids in moving domains. The authors first provide all of the details of existence and uniqueness of the flow in both strong and weak cases. After establishing several important principles and methods, they devote several chapters to demonstrating Eulerian evolution and derivation tools for the control of systems involving fluids and solids. The book concludes with the boundary control of fluid-structure interaction systems, followed by helpful appendices that review some of the advanced m...

  5. [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.

  6. The structural evolution of the Zaghouan-Ressas Structural Belt, northern Tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, M.A.; Grocott, J.; Moody, R.T.J. [Kingston University (United Kingdom). School of Geological Science

    1998-12-31

    From Middle Jurassic to Late Cretaceous time the African-European Rift Zone (AERZ), a seaway connecting the western part of the Tethys Ocean to the embryonic Atlantic Ocean, was characterized by sinistral transtension. On the African margin of the AERZ this cause brea-up of Tethyan Triassic and Lower Jurassic evaporite and carbonate platform sequences by linked, strike-slip and normal-slip fault displacements that delineated a system of sedimentary basins separated by horsts. The Zaghouan-Ressas Structural Belt (ZRSB) in northern Tunisia was initiated as a north-tapering horst in this system, bounded to the northwest by a pelagic basin (the Tunisian Trough) in which thick Lower Cretaceous sequences were deposited and to the east by a north-south trending system of reactived Tethyan margin faults. Two models for the structural evolution of the ZRSB during the Atlassic orogeny are evaluated. The first recognizes the importance of facies variation in controlling thrust geometry, but is essentially a thin-skinned model in which detachment on incompetent Triassic strata forms the main control of structural style. The second model emphasizes reactivation of AERZ-related basin margin faults during contraction and accounts for the major folds in the ZRSB at Djebel Zaghouan and Djebel Ressas as forced folds formed by fault inversion. (author)

  7. An SAO-based approach to technology evolution analysis using patent information: Case study—graphene sensors

    Institute of Scientific and Technical Information of China (English)

    Zhengyin; HU; Shu; FANG; Ling; WEI; Yi; WEN; Xian; ZHANG; Min; WANG

    2015-01-01

    Purpose: This paper introduces an approach to technology evolution analysis using patent information based on Subject-Action-Object(SAO) structures.Design/methodology/approach: First, SAO structures were extracted from patent documents and were cleaned. Second, several dimension-reduction techniques were used to generate technology topics. Then, the hierarchical relationships between technology topics were calculated based on patent clustering. Finally, technology evolution maps were drawn by adding a timeline.Findings: This approach can reveal technology evolution processes from multiple perspectives than other approaches.Research limitations: The semantic annotation of an SAO type is not very accurate and the semantic types of technology topics need to be enriched.Practical implications: The approach can be applied to draw technology evolution maps using different types of technology topics such as problem or solution.Originality/value: This approach offers an analytical dimension and more details than existing techniques, and it helps identify fundamental and emerging technologies more accurately and comprehensively.

  8. Structure and magnetic anisotropy evolution in Au/Co/Au sandwiches upon thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wawro, A.; Kurant, Z.; Baczewski, L.T.; Pankowski, P.; Pelka, J.B.; Maneikis, A. [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Bojko, A.; Zablotskii, V.; Maziewski, A. [Institute of Experimental Physics, University of Bialystok, ul. Lipowa 41, 15-424 Bialystok (Poland)

    2006-01-01

    The correlation between structural and magnetic properties of Au(111)/Co(0001)/Au(111) sandwiches with perpendicular magnetic anisotropy, grown by molecular beam epitaxy, has been studied in details. Thermal treatment in the range between room temperature and 300 C at various stages of samples growth process as well as after its completion is applied as a factor modifying the structure of studied specimens. Annealing at 150 C does not affect substantially either crystalline structure or perpendicular magnetic anisotropy. At 250 C the RHEED pattern of Co layers reveals the loss of the lattice coherence with Au underlayer and the analysis of synchrotron radiation reflectometry leads to the conclusion that the continuity of Co layers is lost. Structural evolution upon thermal treatment is well correlated with changes of magnetic anisotropy studied by magnetooptical Kerr effect. After annealing at 250 C magnetization switches from out-of-plane to in-plane orientation, which is explained in terms of interfacial and magnetoelastic contributions to the sample magnetic anisotropy. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Structural dynamics flexibility informs function and evolution at a proteome scale

    Science.gov (United States)

    Nevin Gerek, Zeynep; Kumar, Sudhir; Banu Ozkan, Sefika

    2013-01-01

    Protein structures are dynamic entities with a myriad of atomic fluctuations, side-chain rotations, and collective domain movements. Although the importance of these dynamics to proper functioning of proteins is emerging in the studies of many protein families, there is a lack of broad evidence for the critical role of protein dynamics in shaping the biological functions of a substantial fraction of residues for a large number of proteins in the human proteome. Here, we propose a novel dynamic flexibility index (dfi) to quantify the dynamic properties of individual residues in any protein and use it to assess the importance of protein dynamics in 100 human proteins. Our analyses involving functionally critical positions, disease-associated and putatively neutral population variations, and the rate of interspecific substitutions per residue produce concordant patterns at a proteome scale. They establish that the preservation of dynamic properties of residues in a protein structure is critical for maintaining the protein/biological function. Therefore, structural dynamics needs to become a major component of the analysis of protein function and evolution. Such analyses will be facilitated by the dfi, which will also enable the integrative use of structural dynamics with evolutionary conservation in genomic medicine as well as functional genomics investigations. PMID:23745135

  10. Structural evolution and stability of mechanically alloyed Fe-Ni nanocrystalline

    Institute of Scientific and Technical Information of China (English)

    CHEN Zi; LIU Qi-zheng; MENG Qing-ping; RONG Yong-hua

    2005-01-01

    The structural evolution and stability of Fe100-xNix(x=10, 20, 35, 50) alloys prepared by mechanical alloying were investigated through X-ray diffraction analysis and transmission electron microscopy. The intrinsic conditions of preparation determining phase stability in nanocrystalline were clarified. After being milled for 120 h, the powders of Fe90Ni10 and Fe80Ni20 consist of a single α(bcc) phase, Fe30Ni30 powders are a single γ(fcc), and for Fe65Ni35 powders there is co-existence of α and γ phases. The as-milled Fe80Ni20 powders annealed at 680 ℃ exhibits the stability of high-temperature γ phase at room temperature, which is consistent with the theoretical prediction.

  11. Investigating Protein Structure and Evolution with SCOP2.

    Science.gov (United States)

    Andreeva, Antonina; Howorth, Dave; Chothia, Cyrus; Kulesha, Eugene; Murzin, Alexey G

    2015-03-09

    SCOP2 is a successor to the Structural Classification of Proteins (SCOP) database that organizes proteins of known structure according to their structural and evolutionary relationships. It was designed to provide a more advanced framework for the classification of proteins. The SCOP2 classification is described in terms of a directed acyclic graph in which each node defines a relationship of particular type that is represented by a region of protein structure and sequence. The SCOP2 data are accessible via SCOP2-Browser and SCOP2-Graph. This protocol unit describes different ways to explore and investigate the SCOP2 evolutionary and structural groupings.

  12. The Geophysics of Mercury: Shape, Interior Structure and Thermal Evolution from MESSENGER

    Science.gov (United States)

    Zuber, M. T.; Phillips, R. J.; Smith, D. E.; Solomon, S. C.; Hauck, S. A.; Head, J. W.; Lemoine, F. G.; Neumann, G. A.; Peale, S. J.; Margot, J.; Johnson, C. L.; Oberst, J.; Purucker, M. E.; Mazarico, E.; Perry, M. E.; Barnouin, O. S.; McNutt, R. L.

    2011-12-01

    The surface and interior of Mercury preserve collectively the record of processes that contributed to the planet's thermal evolution: accretion, differentiation, orbital, rotational and internal dynamics, impact cratering, tectonics and volcanism. Reconstructing Mercury's evolution requires relating internal structure and planetary dynamics to topography, chemistry and surface geology. Observations from the Mercury Laser Altimeter (MLA) and Radio Science (RS) experiments from the flyby and orbital phases of the MESSENGER mission are being analyzed in support of that goal. The MLA obtains returns from the surface at slant ranges fit of low-latitude topography confirms the ellipsoidal shape and orientation of the equator and a 0.015o downward to east slope indicative of an offset between the center of mass and center of figure in the equatorial plane. This distinctive feature of the planetary shape reflects an east-west hemispheric difference in internal structure that could potentially arise from crustal thickness or crustal density variations, large-scale mantle density variations, or topography along the Mercury's core-mantle boundary. The floor of the major impact basin Caloris has been significantly modified, with the northern sections rising above the basin rim. The north polar region shows an irregular topographic depression of 2-4 km depth centered on the north pole. The feature may have migrated to the pole due to reorientation of the planet's inertia axes. The depression could represent a non-hydrostatic contribution to the planetary flattening that must be isolated and removed prior to interpreting the flattening in the context of the radial distribution of interior mass. Analysis of X-band Doppler tracking of MESSENGER has resulted in a 20th degree and order global gravity field, with high degree and order coefficients resolved only in the north. Present are mass anomalies that correlate with some impact basins that hold the promise of modeling to

  13. Transient evolution of the global mode in turbulent swirling jets: experiments and modal stability analysis

    CERN Document Server

    Rukes, Lothar; Paschereit, Oliver; Oberleithner, Kilian

    2016-01-01

    Modal linear stability analysis has proven very successful in the analysis of coherent structures of turbulent flows. Formally, it describes the evolution of a disturbance in the limit of infinite time. In this work we apply modal linear stability analysis to a turbulent swirling jet undergoing a control parameter transient. The flow undergoes a transition from a non-vortex breakdown state to a state with a strong recirculation bubble and the associated global mode. High-speed Particle Image Velocimetry (PIV) measurements are the basis for a local linear stability analysis of the temporarily evolving base flow. This analysis reveals that the onset of the global mode is strongly linked to the formation of the internal stagnation point. Several transition scenarios are discussed and the ability of a frequency selection criterion to predict the wavemaker location, frequency and growth rate of the global mode are evaluated. We find excellent agreement between the linear global mode frequency and the experimental ...

  14. Coupled stratigraphic and structural evolution of a glaciated orogenic wedge, offshore St. Elias orogen, Alaska

    Science.gov (United States)

    Worthington, Lindsay L.; Gulick, Sean P. S.; Pavlis, Terry L.

    2010-12-01

    The St. Elias orogen is the result of ˜10 Myr of oblique convergence and flat-slab subduction in the Gulf of Alaska between North America and the Yakutat microplate. Extensive glaciation and a complex tectonic environment make this region a unique case study in which to examine the details of terrane accretion and the possible coupled influence of climate and tectonic drivers on the structural and topographic evolution of an orogenic wedge. Reflection seismic profiles across the offshore Pamplona zone fold-thrust belt, the frontal St. Elias orogenic wedge, provide constraints for quantifying Pleistocene deformation recorded in the glaciomarine Yakataga formation. The total amount of Pleistocene shortening observed varies from ˜3 to 5 mm/yr, compared to the current GPS-derived Yakutat-North America convergence rate across the St. Elias orogen of ˜45 mm/yr. Growth strata and kinematic fold analysis allow comparison of relative timing of fault activity, which reveals temporal and spatial shifting of active deformation during the glacial period: faulting localized adjacent to the coastline and at the current submarine deformation front. The abandoned, currently inactive region is colocated with the major glacial depocenter in the region, the Bering Trough. These observations imply that glacial processes such as sediment loading and focused erosion during advance-retreat cycles has a direct effect on the evolution of individual faults within the Pamplona zone and the overall deformation pattern in the offshore St. Elias margin. This information provides key constraints for understanding how climatic shifts may have affected the evolution of margin architecture during Pleistocene glacial-interglacial periods.

  15. The evolution of composite materials in submarine structures.

    OpenAIRE

    Lemiere, Y

    1992-01-01

    Since the sixties, the amount of composite structures on submarines has increased continuously. The main reasons are their low apparent weight in water, good behaviour in a marine environment, excellent mechanical properties and acoustic transparency. The new applications required the use of prepreg. Relevant processes had to be adapted to the large dimensions and thickness of the structures. Future applications will be concerned with both structures and internal equipment. A lively debate is...

  16. Transposon Insertions, Structural Variations, and SNPs Contribute to the Evolution of the Melon Genome.

    Science.gov (United States)

    Sanseverino, Walter; Hénaff, Elizabeth; Vives, Cristina; Pinosio, Sara; Burgos-Paz, William; Morgante, Michele; Ramos-Onsins, Sebastián E; Garcia-Mas, Jordi; Casacuberta, Josep Maria

    2015-10-01

    The availability of extensive databases of crop genome sequences should allow analysis of crop variability at an unprecedented scale, which should have an important impact in plant breeding. However, up to now the analysis of genetic variability at the whole-genome scale has been mainly restricted to single nucleotide polymorphisms (SNPs). This is a strong limitation as structural variation (SV) and transposon insertion polymorphisms are frequent in plant species and have had an important mutational role in crop domestication and breeding. Here, we present the first comprehensive analysis of melon genetic diversity, which includes a detailed analysis of SNPs, SV, and transposon insertion polymorphisms. The variability found among seven melon varieties representing the species diversity and including wild accessions and highly breed lines, is relatively high due in part to the marked divergence of some lineages. The diversity is distributed nonuniformly across the genome, being lower at the extremes of the chromosomes and higher in the pericentromeric regions, which is compatible with the effect of purifying selection and recombination forces over functional regions. Additionally, this variability is greatly reduced among elite varieties, probably due to selection during breeding. We have found some chromosomal regions showing a high differentiation of the elite varieties versus the rest, which could be considered as strongly selected candidate regions. Our data also suggest that transposons and SV may be at the origin of an important fraction of the variability in melon, which highlights the importance of analyzing all types of genetic variability to understand crop genome evolution.

  17. Evolution of Wurtzite Structured GaAs Shells Around InAs Nanowire Cores

    Directory of Open Access Journals (Sweden)

    Kim Y

    2009-01-01

    Full Text Available Abstract GaAs was radially deposited on InAs nanowires by metal–organic chemical vapor deposition and resultant nanowire heterostructures were characterized by detailed electron microscopy investigations. The GaAs shells have been grown in wurtzite structure, epitaxially on the wurtzite structured InAs nanowire cores. The fundamental reason of structural evolution in terms of material nucleation and interfacial structure is given.

  18. Structural evolution of yttrium nanolayer inserted in FeNi/Y nanomultilayered film

    Energy Technology Data Exchange (ETDEWEB)

    Li, Wei, E-mail: liwei176@usst.edu.cn; Liu, Ping; Zhang, Ke; Ma, Fengcang; Liu, Xinkuan; Chen, Xiaohong; He, Daihua

    2014-10-30

    Graphical abstract: - Highlights: • The FeNi/Y nanomultilayers with different Y layer thickness were synthesized. • The structural evolution of Y nanolayer within FeNi/Y nanomultilayer was studied. • The microstructural evolution sequence of Y layer was fcc→amorphous→hcp structure. • The microstructural evolution of Y nanolayer was explained by a thermodynamic model. - Abstract: The FeNi/Y nanomultilayered films with different Y layer thickness (t{sub Y}) were synthesized by magnetron sputtering. The structural evolution of Y nanolayer with increase in t{sub Y} was investigated. When t{sub Y} was less than 2 nm, Y layers transformed to fcc structure under the template effect of FeNi layers and grew epitaxially with FeNi. With t{sub Y} of 3 nm, Y layers could not maintain the epitaxial growth, but present a transient amorphous state. As t{sub Y} further increases to 4 nm, Y layers transformed into the stable hcp structure. The microstructural evolution sequence of Y layers was fcc→amorphous→hcp structure, which could be explained by a thermodynamic model.

  19. Visualization and Evolution of the Scientific Structure of Fuzzy Sets Research in Spain

    Science.gov (United States)

    Lopez-Herrera, A. G.; Cobo, M. J.; Herrera-Viedma, E.; Herrera, F.; Bailon-Moreno, R.; Jimenez-Contreras, E.

    2009-01-01

    Introduction: Presents the first bibliometric study on the evolution of the fuzzy sets theory field. It is specially focused on the research carried out by the Spanish community. Method. The CoPalRed software, for network analysis, and the co-word analysis technique are used. Analysis: Bibliometric maps showing the main associations among the…

  20. Precambrian crustal evolution and Cretaceous–Palaeogene faulting in West Greenland: Structural analysis of the northern Nagssugtoqidian orogen, West Greenland: an example of complex tectonic patterns in reworked high-grade metamorphic terrains

    Directory of Open Access Journals (Sweden)

    Mazur, Stanislaw

    2006-12-01

    Full Text Available Structural analysis of the deeply eroded northern flank of the Palaeoproterozoic Nagssugtoqidian orogen shows marked regional variations in both the orientation and type of fabrics, as is characteristic of Precambrian high-grade terrains subjected to polyphase deformation. Here we investigate the relationship between strain, metamorphic grade, and the resulting structural patterns. The study area south of Aasiaat in West Greenland consists of amphibolite- togranulite-gradeArchaean orthogneisses and relatively thin supracrustal units. The regional foliation displays a WSW–ENE to SW–NE strike associated with steep to moderate dips towards the WNW or SSE. Lineation trends are WSW–ENE and generally plunge gently towards the WSW. Mesoscopic fold hinges are usually colinear with the regional lineation. A systematic change in the plunge of lineations occurs across the south-western part of the study area. Towards the south, the lineation plunge progressively increases, despite the generally uniform strike of foliation. This southward increase of lineation pitch is typically associated with the transition from L > S or L = S shape fabrics in rocks characterised by a low pitch, to S > L or S fabrics in the zone of moderate to high pitch. The structural patterns point to subdivision of the study area into a southern domain mostly characterised by S or S > L shape fabrics and a moderate to high angle of lineation pitch, and a northern domain showing L > S or L = S fabrics and low angles of lineation pitch. This subdivision corresponds well with the map scale boundary between granulite facies rocks in the south and amphibolite facies rocks farther north. The observed structural pattern may be explained by two alternative tectonic models: (1 northward indentation of the previously cooled granulite block into the rheologically weaker amphibolite domain, and (2 strain partitioning within a mid-crustal transpression zone. In model 2 the northern domain

  1. Tectonic evolution and mantle structure of the Caribbean

    NARCIS (Netherlands)

    van Benthem, S.; Govers, R.; Spakman, W.; Wortel, R.

    2013-01-01

    We investigate whether predictions of mantle structure from tectonic reconstructions are in agreement with a detailed tomographic image of seismic P wave velocity structure under the Caribbean region. In the upper mantle, positive seismic anomalies are imaged under the Lesser Antilles and Puerto Ric

  2. 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.

  3. 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...

  4. Tabletop imaging of structural evolutions in chemical reactions

    CERN Document Server

    Ibrahim, Heide; Beaulieu, Samuel; Schmidt, Bruno E; Thiré, Nicolas; Bisson, Éric; Hebeisen, Christoph T; Wanie, Vincent; Giguére, Mathieu; Kieffer, Jean-Claude; Sanderson, Joseph; Schuurman, Michael S; Légaré, François

    2014-01-01

    The introduction of femto-chemistry has made it a primary goal to follow the nuclear and electronic evolution of a molecule in time and space as it undergoes a chemical reaction. Using Coulomb Explosion Imaging we have shot the first high-resolution molecular movie of a to and fro isomerization process in the acetylene cation. So far, this kind of phenomenon could only be observed using VUV light from a Free Electron Laser [Phys. Rev. Lett. 105, 263002 (2010)]. Here we show that 266 nm ultrashort laser pulses are capable of initiating rich dynamics through multiphoton ionization. With our generally applicable tabletop approach that can be used for other small organic molecules, we have investigated two basic chemical reactions simultaneously: proton migration and C=C bond-breaking, triggered by multiphoton ionization. The experimental results are in excellent agreement with the timescales and relaxation pathways predicted by new and definitively quantitative ab initio trajectory simulations.

  5. Shifting the Starspot Paradigm through Imaging Magnetic Structures and Evolution

    Science.gov (United States)

    Roettenbacher, Rachael M.

    2016-08-01

    Magnetism is present in stars across all masses and evolutionary states. For cool stars with a convective outer envelope, stellar magnetic fields are generated through complex interactions between the convective layer and radiative core due to rotation. Magnetism in cool stars fuels stellar activity, in particular as starspots. Using starspots as a proxy, this work concentrates on imaging stellar magnetism. With state-of-the-art observations and imaging techniques, I investigate shifting the spot paradigm of localized starspots blemishing an otherwise bright surface (analogous to the solar photosphere) to a surface hosting a widespread network of magnetically-suppressed convection. This network is capable of affecting measurements of fundamental stellar parameters, such as radius and temperature, leading to inaccurate mass and age estimates. To accomplish this shift, I use precision Kepler data and a light-curve inversion algorithm for studies of stellar differential rotation and starspot evolution. Additionally, with long-baseline interferometric data collected with the Michigan Infrared Combiner (MIRC) at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array, I target the bright, spotted, giant primary stars of close binary (RS CVn) systems. For these stars, I combine interferometric detections with radial velocity data to measure orbital and stellar parameters, which are used in concert with long-term photometric light curves to observe ellipsoidal variations, measure gravity darkening, and isolate the starspot signatures. In direct imaging using the interferometric data, I observe a spotted RS CVn star through an entire rotation period to detect canonical starspots, a polar starspot, and globally-suppressed convection. The regions of magnetically-suppressed convection cover a large fraction of the surface, potentially impacting estimates of stellar parameters. The combination of these efforts provides a start to a new era of

  6. Natural evolution inspired design of light trapping structure in thin film organic solar cells

    Science.gov (United States)

    Wang, Chen; Yu, Shuangcheng; Chen, Wei; Sun, Cheng

    2013-09-01

    Light trapping has been developed to effectively enhance the efficiency of the thin film solar cell by extending the pathlength for light interacting with the active materials. Searching for optimal light trapping design requires a delicate balance among all the competing physical processes, including light refraction, reflection, and absorption. The existing design methods mainly depend on engineers' intuition to predefine the topology of the light-trapping structure. However, these methods are not capable of handling the topological variation in reaching the optimal design. In this work, a systematic approach based on Genetic Algorithm is introduced to design the scattering pattern for effective light trapping. Inspired by natural evolution, this method can gradually improve the performance of light trapping structure through iterative procedures, producing the most favorable structure with minimized reflection and substantial enhancement in light absorption. Both slot waveguide based solar cell and a more realistic organic solar with a scattering layer consisting of nano-scale patterned front layer is optimized to maximize absorption by strongly coupling incident sun light into the localized photonic modes supported by the multilayer system. Rigorous coupled wave analysis (RCWA) is implemented to evaluate the absorbance. The optimized slot waveguide cell achieves a broadband absorption efficiency of 48.1% and more than 3-fold increase over the Yablonovitch limit and the optimized realistic organic cell exhibits nearly 50% average absorbance over the solar spectrum with short circuit current density five times larger than the control case using planar ITO layer.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    This study presents a phylogenetic analysis of 198 MADS-box genes based on 420 parsimony-informative characters. The analysis includes only MIKC genes; therefore several genes from gymnosperms and pteridophytes are excluded. The strict consensus tree identifies all major monophyletic groups known...... three classes of MADS-box genes to be transcribed in the stamens and carpels. Thus the analysis does not support the ABC model as formulated at present....

  8. Evolution of dislocation structure and modelling of deformation resistance in CaF2 single crystals

    OpenAIRE

    Sadrabadi, Peiman

    2007-01-01

    he evolution of dislocation structure during plastic deformation in pure 111}-oriented CaF2 single crystals was investigated at constant strain rate (10−5 s−1) and constant stress (1 < / MPa < 22) in the temperature range of 0.5 < T/Tm < 0.8. The steady state and transient deformation behavior of the material is described by the composite model on the basis of microstructural data. In the following sections the important conclusions are briefly summarized. Microstructure evolution...

  9. 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

  10. Design of structurally distinct proteins using strategies inspired by evolution.

    Science.gov (United States)

    Jacobs, T M; Williams, B; Williams, T; Xu, X; Eletsky, A; Federizon, J F; Szyperski, T; Kuhlman, B

    2016-05-06

    Natural recombination combines pieces of preexisting proteins to create new tertiary structures and functions. We describe a computational protocol, called SEWING, which is inspired by this process and builds new proteins from connected or disconnected pieces of existing structures. Helical proteins designed with SEWING contain structural features absent from other de novo designed proteins and, in some cases, remain folded at more than 100°C. High-resolution structures of the designed proteins CA01 and DA05R1 were solved by x-ray crystallography (2.2 angstrom resolution) and nuclear magnetic resonance, respectively, and there was excellent agreement with the design models. This method provides a new strategy to rapidly create large numbers of diverse and designable protein scaffolds.

  11. Malate dehydrogenase: a model for structure, evolution, and catalysis.

    OpenAIRE

    1994-01-01

    Malate dehydrogenases are widely distributed and alignment of the amino acid sequences show that the enzyme has diverged into 2 main phylogenetic groups. Multiple amino acid sequence alignments of malate dehydrogenases also show that there is a low degree of primary structural similarity, apart from in several positions crucial for nucleotide binding, catalysis, and the subunit interface. The 3-dimensional structures of several malate dehydrogenases are similar, despite their low amino acid s...

  12. The tRNA Elbow in Structure, Recognition and Evolution

    Directory of Open Access Journals (Sweden)

    Jinwei Zhang

    2016-01-01

    Full Text Available Prominent in the L-shaped three-dimensional structure of tRNAs is the “elbow” where their two orthogonal helical stacks meet. It has a conserved structure arising from the interaction of the terminal loops of the D- and T-stem-loops, and presents to solution a flat face of a tertiary base pair between the D- and T-loops. In addition to the ribosome, which interacts with the elbow in all three of its tRNA binding sites, several cellular RNAs and many proteins are known to recognize the elbow. At least three classes of non-coding RNAs, namely 23S rRNA, ribonuclease P, and the T-box riboswitches, recognize the tRNA elbow employing an identical structural motif consisting of two interdigitated T-loops. In contrast, structural solutions to tRNA-elbow recognition by proteins are varied. Some enzymes responsible for post-transcriptional tRNA modification even disrupt the elbow structure in order to access their substrate nucleotides. The evolutionary origin of the elbow is mysterious, but, because it does not explicitly participate in the flow of genetic information, it has been proposed to be a late innovation. Regardless, it is biologically essential. Even some viruses that hijack the cellular machinery using tRNA decoys have convergently evolved near-perfect mimics of the tRNA elbow.

  13. A SIMPLE ANALYSIS OF THE GEOTECTONIC EVOLUTIONAL CHARACTERS OF TONGLIN AREA,ANHUI

    Institute of Scientific and Technical Information of China (English)

    SHAO; Yong-jun; PENG; Sheng-lin; LIU; Liang-ming

    2001-01-01

    Tonglin area is one of the areas where there exist many copper ore deposits.The geotectonic property has many titles.Most of geological scholars call it the lower Yangtze platform depression and divide the geotectonic stages into formation of basement,sedimentaion of cover and intreplate deformation.According to the diwa theory,this paper classifies it as the Jiangsu-Hubei geodepressional system of the Central China geodepressional region.According to the analysis of the features of structural layers,the geotectonic evolution of the region is divided into four stages: pre-geosyncline,geosyncline,platform and diwa.

  14. Diagnostics and future evolution analysis of the two parametric models

    CERN Document Server

    Yang, Guang; Meng, Xinhe

    2016-01-01

    In this paper, we apply three diagnostics including $Om$, Statefinder hierarchy and the growth rate of perturbations into discriminating the two parametric models for the effective pressure with the $\\Lambda$CDM model. By using the $Om$ diagnostic, we find that both the model 1 and the model 2 can be hardly distinguished from each other as well as the $\\Lambda$CDM model in terms of 68\\% confidence level. As a supplement, by using the Statefinder hierarchy diagnostics and the growth rate of perturbations, we discover that not only can our two parametric models be well distinguished from $\\Lambda$CDM model, but also, by comparing with $Om$ diagnostic, the model 1 and the model 2 can be distinguished better from each other. In addition, we also explore the fate of universe evolution of our two models by means of the rip analysis.

  15. BASE-9: Bayesian Analysis for Stellar Evolution with nine variables

    Science.gov (United States)

    Robinson, Elliot; von Hippel, Ted; Stein, Nathan; Stenning, David; Wagner-Kaiser, Rachel; Si, Shijing; van Dyk, David

    2016-08-01

    The BASE-9 (Bayesian Analysis for Stellar Evolution with nine variables) software suite recovers star cluster and stellar parameters from photometry and is useful for analyzing single-age, single-metallicity star clusters, binaries, or single stars, and for simulating such systems. BASE-9 uses a Markov chain Monte Carlo (MCMC) technique along with brute force numerical integration to estimate the posterior probability distribution for the age, metallicity, helium abundance, distance modulus, line-of-sight absorption, and parameters of the initial-final mass relation (IFMR) for a cluster, and for the primary mass, secondary mass (if a binary), and cluster probability for every potential cluster member. The MCMC technique is used for the cluster quantities (the first six items listed above) and numerical integration is used for the stellar quantities (the last three items in the above list).

  16. Heterogeneous Deployment Analysis for Cost-Effective Mobile Network Evolution

    DEFF Research Database (Denmark)

    Coletti, Claudio

    2013-01-01

    The plethora of connected devices, such as attractive smartphones, data dongles and 3G/4G built-in tablet computers, has brought mobile operators to face increasing demand in mobile broadband traffic and services. In addition to the roll-out of Long Term Evolution (LTE), the deployment of small low...... available at the macro layer for wireless backhaul. The main goal is to investigate the LTE downlink performance of different deployment configurations, focusing on spectrum allocation schemes and deployment strategies that are needed to maximize network coverage. Differently from most studies using...... statistical models of deployment areas, the performance analysis is carried out in the form of operator case studies for large-scale deployment scenarios, including realistic macro network layouts and inhomogeneous spatial traffic distributions. Deployment of small cells is performed by means of proposed...

  17. Three-dimensional evolution of flow structures in transitional circular and chevron jets

    Science.gov (United States)

    Violato, Daniele; Scarano, Fulvio

    2011-12-01

    The three-dimensional behavior of flow transition in circular and 6-chevron jets at Re = 5000 is investigated with experiments conducted on a free water jet by time-resolved tomographic particle image velocimetry. The emphasis is on the unsteady organization of coherent flow structures, which play a role in the generation of acoustic noise. Shedding and pairing of vortices are the most pronounced phenomena observed in the near field of the circular jet. The first and second pairing amplify the axial pulsatile motion in the jet column and lead to the growth of azimuthal waves culminating in the breakup of the vortex ring. Streamwise vortices of axial and radial vorticity are observed in the outer region and move inward and outward under the effect of the vortex rings. In the jet with chevrons, the axisymmetric ring-like coherence of the circular jet is not encountered. Instead, streamwise flow structures of azimuthal vorticity emanate from the chevron apices, and counter-rotating streamwise vortices of axial and radial vorticity develop from the chevron notches. The decay of streamwise vortices is accompanied by the formation of C-shaped structures. The three-dimensional analysis allows quantifying the vortex stretching and tilting activity, which, for the circular jet exit, is related to the azimuthal instabilities and the streamwise vortices connecting the vortex rings. In the chevron jet, stretching and tilting peak during the formation of C-structures. Following Powell's aeroacoustic analogy, the spatial distribution of the source term is mapped, evaluating the temporal derivative of the Lamb vector. The spatio-temporal evolution of such source term is visualized revealing that the events of highest activity are associated with the processes of vortex-ring pairing and vortex-ring disruption for the circular jet, and with the decay of streamwise instabilities and the formation of C-shaped structures for the chevron case.

  18. The (De-)evolution of Evolution Games: A Content Analysis of the Representation of Evolution Through Natural Selection in Digital Games

    Science.gov (United States)

    Leith, Alex P.; Ratan, Rabindra A.; Wohn, Donghee Yvette

    2016-08-01

    Given the diversity and complexity of education game mechanisms and topics, this article contributes to a theoretical understanding of how game mechanisms "map" to educational topics through inquiry-based learning. Namely, the article examines the presence of evolution through natural selection (ENS) in digital games. ENS is a fundamentally important and widely misunderstood theory. This analysis of ENS portrayal in digital games provides insight into the use of games in teaching ENS. Systematic database search results were coded for the three principles of ENS: phenotypic variation, differential fitness, and fitness heritability. Though thousands of games use the term evolution, few presented elements of evolution, and even fewer contained all principles of ENS. Games developed to specifically teach evolution were difficult to find through Web searches. These overall deficiencies in ENS games reflect the inherent incompatibility between game control elements and the automatic process of ENS.

  19. Local atomic structure modulations activate metal oxide as electrocatalyst for hydrogen evolution in acidic water.

    Science.gov (United States)

    Li, Yu Hang; Liu, Peng Fei; Pan, Lin Feng; Wang, Hai Feng; Yang, Zhen Zhong; Zheng, Li Rong; Hu, P; Zhao, Hui Jun; Gu, Lin; Yang, Hua Gui

    2015-08-19

    Modifications of local structure at atomic level could precisely and effectively tune the capacity of materials, enabling enhancement in the catalytic activity. Here we modulate the local atomic structure of a classical but inert transition metal oxide, tungsten trioxide, to be an efficient electrocatalyst for hydrogen evolution in acidic water, which has shown promise as an alternative to platinum. Structural analyses and theoretical calculations together indicate that the origin of the enhanced activity could be attributed to the tailored electronic structure by means of the local atomic structure modulations. We anticipate that suitable structure modulations might be applied on other transition metal oxides to meet the optimal thermodynamic and kinetic requirements, which may pave the way to unlock the potential of other promising candidates as cost-effective electrocatalysts for hydrogen evolution in industry.

  20. Evolution of the thematic structure of oncology based on the co-word analysis%基于共词分析的世界肿瘤学研究主题演化分析

    Institute of Scientific and Technical Information of China (English)

    程薛柯; 苏成

    2015-01-01

    categorized the keywords according to the Medical Subject Headings (MeSH)manually.In the end,we builted the co-occurrence matrixes of high-frequency words in three stages:2005—2007,2008—2010 and 2011 —2014, and drew the evolution maps and strategic diagrams of each stage to analyze the changes of the internal structure and research topics of oncology.Results While the word frequence increasing rapidly,the main keywords reduced gradually from 2005 to 2014.The traditional treatments such as chemotherapy and radiotherapy,the diagnostic and the epidemiological investigation were the core subject of oncology.With the screening of neoplasms,the research on the cell physiological phenomena and the genetic phenomena gained vigorous expan-sion."Breast neoplasms",the topic whose deep exploration also led the development of other topics,has always been the hard nut as well as the hot topic of the oncology.During this period,researches on the screening of neo-plasms and the genetic phenomena were developed rapidly.Conclusion The content of oncology will be more thoroughly with some merge,division,development,declining and perishing of the internal themes occurred as well.The boundaries among the sub-structure are becoming more and more blurred and the screening of neo-plasms and the genetic phenomena has gradually become the dominant trend in general practices.

  1. Evolution of the Alboran Sea hydrographic structures during July 1993

    Science.gov (United States)

    Lafuente, Jesús García.; Cano, Natalio; Vargas, Manuel; Rubín, Juan P.; Hernández-Guerra, Alonso

    1998-01-01

    During the ICTIOALBORAN-0793 multidisciplinary oceanographic survey carried out in July 1993 by the Instituto Español de Oceanografı´a (IEO) in the Alboran Sea, some anomalous features were detected. One was the presence of a small cyclonic eddy in the western Alboran Basin, close to the African coast. The upper layer of the eddy consisted of Mediterranean Surface Water and was separated from its supposed source (the northern Alboran Sea) by the Atlantic Jet. Another feature was the probable temporary interruption of the flow of fresh Atlantic Water (S≈36.5) into the eastern Alboran Basin and its replacement by a modified (saltier) Atlantic Water. These features can be explained assuming a time evolution of the surface circulation in the Alboran Sea forced by speed variations in the inflowing Atlantic Water through the Strait of Gibraltar. A collection of satellite images covering the survey period and across-strait sea level difference data, indicative of the geostrophic velocity of the inflow through the Strait, were used to check this assumption. Both sets of data supplied independent but compatible information in the sense that they complemented each other and gave support to the proposed evolving model. Finally, some speculative ideas attempting to correlate the inferred variability in the Alboran Sea with the state of the baroclinic water exchange through the Strait of Gibraltar (maximal or submaximal) are discussed.

  2. Quasar Evolution Driven by Galaxy Encounters in Hierarchical Structures

    CERN Document Server

    Menci, N; Fontana, A; Giallongo, E; Poli, F; Vittorini, V

    2003-01-01

    We link the evolution of the galaxies in the hierarchical clustering scenario with the changing accretion rates of cold gas onto the central massive black holes that power the quasars. We base on galaxy interactions as main triggers of accretion; the related scaling laws are taken up from Cavaliere & Vittorini (2000), and grafted to a semi-analytic code for galaxy formation. As a result, at high $z$ the protogalaxies grow rapidly by hierarchical merging; meanwhile, much fresh gas is imported and also destabilized, so the holes are fueled at their full Eddington rates. At lower $z$ the galactic dynamical events are mostly encounters in hierarchically growing groups; now the refueling peters out, as the residual gas is exhausted while the destabilizing encounters dwindle. So, with no parameter tuning other than needed for stellar observables, our model uniquely produces at $z>3$ a rise, and at $z\\lesssim 2.5 $ a decline of the bright quasar population as steep as observed. In addition, our results closely f...

  3. Total Lightning Characteristics and Electric Structure Evolution in a Hailstorm

    Institute of Scientific and Technical Information of China (English)

    ZHENG Dong; ZHANG Yijun; MENG Qing; LU Weitao; YI Xiaoyuan

    2009-01-01

    In this paper, total lightning data observed by SAFIR3000 3-D Lightning Locating System was combined with radar data to analyze characteristics of the lightning activity and electric structure of a hailstorm that occurred in Beijing on 31 May 2005. The results indicated that there were two active periods for the lightning activity during the hailstorm process. The hail shooting was found in the first period. After the end of the hail shooting, lightning frequency decreased suddenly. However, more active lightning activities occurred in the second period with lots of them appearing in the cloud anvil region. The peak of the lightning frequency came about 5 rain prior to the hail shooting. Only 6.16% of the total lightning was cloud-to-ground (CG) lightning, among which 20% had positive polarity. This percentage was higher than that in normal thunderstorms. In addition, heavier positive CG lightning discharge occurred before rather than after the hail shooting. In the stage of the hail shooting, the electric structure of the hailstorm was inverted, with the main negative charge region located around the -40℃ level and the main positive charge region around the -15℃ level. In addition, a weak negative charge region existed below the positive charge region transitorily. After the hail shooting, the electric structure underwent fast and persistent adjustments and became a normal tripole, with positive charge in the upper and lower levels and negative charge in the middle levels. However, the electric structure was tilted under the influence of the westerly wind in the middle and upper levels. The lightning activity and electric structure were closely related to the dynamic and microphysical processes of the hailstorm. It was believed that severe storms with stronger updrafts were more conducive to an inverted tripolar electric structure than normal thunderstorms, and the inverted distribution could then facilitate more positive CG lightning in the severe storms.

  4. Correlation between atomic structure evolution and strength in a bulk metallic glass at cryogenic temperature.

    Science.gov (United States)

    Tan, J; Wang, G; Liu, Z Y; Bednarčík, J; Gao, Y L; Zhai, Q J; Mattern, N; Eckert, J

    2014-01-28

    A model Zr41.25Ti13.75Ni10Cu12.5Be22.5 (at.%) bulk metallic glass (BMG) is selected to explore the structural evolution on the atomic scale with decreasing temperature down to cryogenic level using high energy X-ray synchrotron radiation. We discover a close correlation between the atomic structure evolution and the strength of the BMG and find out that the activation energy increment of the concordantly atomic shifting at lower temperature is the main factor influencing the strength. Our results might provide a fundamental understanding of the atomic-scale structure evolution and may bridge the gap between the atomic-scale physics and the macro-scale fracture strength for BMGs.

  5. Structural constraints on the evolution of the collagen fibril: convergence on a 1014-residue COL domain.

    Science.gov (United States)

    Slatter, David Anthony; Farndale, Richard William

    2015-05-01

    Type I collagen is the fundamental component of the extracellular matrix. Its α1 gene is the direct descendant of ancestral fibrillar collagen and contains 57 exons encoding the rod-like triple-helical COL domain. We trace the evolution of the COL domain from a primordial collagen 18 residues in length to its present 1014 residues, the limit of its possible length. In order to maintain and improve the essential structural features of collagen during evolution, exons can be added or extended only in permitted, non-random increments that preserve the position of spatially sensitive cross-linkage sites. Such sites cannot be maintained unless the twist of the triple helix is close to 30 amino acids per turn. Inspection of the gene structure of other long structural proteins, fibronectin and titin, suggests that their evolution might have been subject to similar constraints.

  6. 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 struc

  7. Structure and tectonic evolution of the northeastern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ramana, M.V.; Krishna, K.S.; Ramprasad, T.; Desa, M.; Subrahmanyam, V.; Sarma, K.V.L.N.S.

    , (3) identification of the Cretaceous magnetic smooth zone and the boundary of the late Cretaceous crust in the distal part of the Bengal Fan, (4) structure and origin of the 85 degrees E Ridge, seismic stratigraphy, the presence of carbonate buildup...

  8. Directed enzyme evolution guided by multidimensional analysis of substrate-activity space.

    Science.gov (United States)

    Larsson, Anna-Karin; Emrén, Lars O; Bardsley, William G; Mannervik, Bengt

    2004-01-01

    The directed evolution of protein function frequently involves identification of mutants with improved properties from a population of variants obtained by mutagenesis. The selection of clones to parent the subsequent generation is crucial to the continued creation of superior progeny. In the present study, multivariate analysis guided the evolution of human glutathione transferase (GST) T1-1 to 65-fold enhanced alkyltransferase activity. Six alternative substrates monitored the substrate-activity space that characterized a mutant library of enzymes, obtained by recombination of DNA and heterologous expression in Escherichia coli. A subset of mutants was identified by their proximity in the targeted region of six-dimensional factor space. DNA from these mutants was recombined to create a new generation of GST variants from which an improved enzyme was isolated. The multidimensional cluster analysis is applicable to quantitative properties in any population of molecules undergoing evolution and can guide the tailoring of proteins, nucleic acids and other chemical structures to novel and improved functions.

  9. The structure and evolution of cold dark matter halos

    CERN Document Server

    Diemand, Jürg

    2009-01-01

    In the standard cosmological model a mysterious cold dark matter (CDM) component dominates the formation of structures. Numerical studies of the formation 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 th...

  10. Structural evolution of the Vuotso area, Finnish Lapland

    Directory of Open Access Journals (Sweden)

    Mikko Nironen

    2003-01-01

    Full Text Available The Vuotso area is structurally interesting because the fold interference pattern in rocks of central Lapland changes into thrust-related foliation of the Lapland Granulite Belt. A felsic volcanic rock yielded a 2.45 Ga age and conformed that the volcanic rocks in the Vuotso area are (mainly Paleoproterozoic. A structural sequence with recumbent F2 folding and predominant S2 foliation, and an interference pattern of F3 and F4 foldings could be discerned in the supracrustal rocks. A large D3 antiform is overprinted by mafic-intermediate gneisses that form the basal part of the thrust sequence. The curving of late D3 shear zones suggests that D3 deformation may be associated with thrusting from east-northeast, but thrusting of the granulites and adjacent mafic-intermediate gneisses to their present position is interpreted as a post-D3 event.

  11. Computer System for Analysis of Molecular Evolution Modes (SAMEM): analysis of molecular evolution modes at deep inner branches of the phylogenetic tree.

    Science.gov (United States)

    Gunbin, Konstantin V; Suslov, Valentin V; Genaev, Mikhail A; Afonnikov, Dmitry A

    SAMEM (System for Analysis of Molecular Evolution Modes), a web-based pipeline system for inferring modes of molecular evolution in genes and proteins (http://pixie.bionet.nsc.ru/samem/), is presented. Pipeline 1 performs analyses of protein-coding gene evolution; pipeline 2 performs analyses of protein evolution; pipeline 3 prepares datasets of genes and/or proteins, performs their primary analysis, and builds BLOSUM matrices; pipeline 4 checks if these genes really are protein-coding. Pipeline 1 has an all-new feature, which allows the user to obtain K(R)/K(C) estimates using several different methods. An important feature of pipeline 2 is an original method for analyzing the rates of amino acid substitutions at the branches of a phylogenetic tree. The method is based on Markov modeling and a non-parametric permutation test, which compares expected and observed frequencies of amino acid substitutions, and infers the modes of molecular evolution at deep inner branches.

  12. Papain-like peptidases: structure, function, and evolution.

    Science.gov (United States)

    Novinec, Marko; Lenarčič, Brigita

    2013-06-01

    Papain-like cysteine peptidases are a diverse family of peptidases found in most known organisms. In eukaryotes, they are divided into multiple evolutionary groups, which can be clearly distinguished on the basis of the structural characteristics of the proenzymes. Most of them are endopeptidases; some, however, evolved into exopeptidases by obtaining additional structural elements that restrict the binding of substrate into the active site. In humans, papain-like peptidases, also called cysteine cathepsins, act both as non-specific hydrolases and as specific processing enzymes. They are involved in numerous physiological processes, such as antigen presentation, extracellular matrix remodeling, and hormone processing. Their activity is tightly regulated and dysregulation of one or more cysteine cathepsins can result in severe pathological conditions, such as cardiovascular diseases and cancer. Other organisms can utilize papain-like peptidases for different purposes and they are often part of host-pathogen interactions. Numerous parasites, such as Plasmodium and flukes, utilize papain-like peptidases for host invasion, whereas plants, in contrast, use these enzymes for host defense. This review presents a state-of-the-art description of the structure and phylogeny of papain-like peptidases as well as an overview of their physiological and pathological functions in humans and in other organisms.

  13. Evolution of polymer photovoltaic performances from subtle chemical structure variations.

    Science.gov (United States)

    Yan, Han; Li, Denghua; Lu, Kun; Zhu, Xiangwei; Zhang, Yajie; Yang, Yanlian; Wei, Zhixiang

    2012-11-21

    Conjugated polymers are promising replacements for their inorganic counterparts in photovoltaics due to their low cost, ease of processing, and straightforward thin film formation. New materials have been able to improve the power conversion efficiency of photovoltaic cells up to 8%. However, rules for rational material design are still lacking, and subtle chemical structure variations usually result in large performance discrepancies. The present paper reports a detailed study on the crystalline structure, morphology, and in situ optoelectronic properties of blend films of polythiophene derivatives and [6,6]-phenyl C61-butyric acid methyl ester by changing the alkyl side chain length and position of polythiophene. The correlation among the molecular structure, mesoscopic morphology, mesoscopic optoelectronic property and macroscopic device performance (highest efficiency above 4%) was directly established. Both solubility and intermolecular interactions should be considered in rational molecular design. Knowledge obtained from this study can aid the selection of appropriate processing conditions that improve blend film morphology, charge transport property, and overall solar cell efficiency.

  14. Stress field evolution law of mining environment reconstructing structure with change of filling height

    Institute of Scientific and Technical Information of China (English)

    CHEN Qing-fa; ZHOU Ke-ping; WANG Li-li

    2010-01-01

    For improving global stability of mining environment reconstructing structure,the stress field evolution law of the structure with the filling height change of low-grade backfill was studied by ADINA finite element analysis code.Three kinds of filling schemes were designed and calculated,in which the filling heights were 2,4,and 7 m,separately.The results show that there are some rules in the stress field with the increase of the filling height as follows:(1)the maximum value of tension stress of the roof decreases gradually,and stress conditions are improved gradually;(2)the tension stress status in the vertical pillar is transformed into the compressive stress status,and the carrying capacity is improved gradually; however,when the filling height is beyond 2.8 m,the carrying capacity of the vertical pillar grows very slowly,so,there is little significance to continue to fill the low-grade backfill;(3)the bottom pillar suffers the squeezing action from the vertical pillars at first and then the gravity action of the low-grade backfill,and the maximum value of tension stress of the bottom pillar firstly increases and then decreases.Considering the economic factor,security and other factors,the low-grade backfill has the most reasonable height(2.8 m)in the scope of all filling height.

  15. Rogers' paradox recast and resolved: population structure and the evolution of social learning strategies.

    Science.gov (United States)

    Rendell, Luke; Fogarty, Laurel; Laland, Kevin N

    2010-02-01

    We explore the evolution of reliance on social and asocial learning using a spatially explicit stochastic model. Our analysis considers the relative merits of four evolved strategies, two pure strategies (asocial and social learning) and two conditional strategies (the "critical social learner," which learns asocially only when copying fails, and the "conditional social learner," which copies only when asocial learning fails). We find that spatial structure generates outcomes that do not always conform to the finding of earlier theoretical analyses that social learning does not enhance average individual fitness at equilibrium (Rogers' paradox). Although we describe circumstances under which the strategy of pure social learning increases the average fitness of individuals, we find that spatial structure introduces a new paradox, which is that social learning can spread even when it decreases the average fitness of individuals below that of asocial learners. We also show that the critical social learner and conditional social learner both provide solutions to the aforementioned paradoxes, although we find some conditions in which pure (random) social learning out-competes both conditional strategies. Finally, we consider the relative merits of critical and conditional social learning under various conditions.

  16. Phase-Field Methods for Structure Evolution in Sheared Multiphase Systems

    Science.gov (United States)

    Badalassi, Vittorio; Ceniceros, Hector; Banerjee, Sanjoy

    2002-01-01

    A homogeneous disordered phase separates into ordered structures when quenched into a broken-symmetry phase. The competition of broken-symmetry phases to select an equilibrium state may be studied in terms of coarse-grained order parameters described by a suitable Landau free-energy function. A network of equilibrium-phase domains develops on quenching and coarsens with time with a topology that may be controlled by shear. We use three-dimensional simulations, in which time-dependent models for conserved-order parameters coupled to Navier-Stokes fluid models are solved, to investigate the evolution of such domains, e.g. spinodal decompositions of polymeric materials under shear. The numerical problems are formidable because of the strong nonlinearities inherent in the coupled model, and these are amongst the first 3D calculations undertaken. In linear shear fields we find stable nanostrings, also recently seen in experiments. The affinity of the ordered phases to boundaries plays a role in the form of the structures that develop, with stacked plate-like phase distributions emerging under certain conditions. Such methods appear quite promising for design and analysis of multiphase and complex fluid formulations. The behavior of foams in such conditions is of particular interest in microgravity environments. Additional information can be found in the original extended abstract.

  17. Evolution, structure and function of hydrologic subsystems in hillslopes

    Science.gov (United States)

    Troch, P. A.; Brooks, P.; Chorover, J.; Huxman, T.; McDonnell, J. J.; Rasmussen, C.; Sivapalan, M.

    2007-12-01

    Hillslopes offer a useful elementary scale to construct catchment hydrologic models, and to understand the role of water in the landscape. However, hillslopes exhibit enormous complexity and heterogeneity, much of which is not easily observable. The complexity is driven by the interactions between water, biogeochemistry, ecology and soils, within the constraints set by the climate and the geologic history of the system. These interactions create complex, non-random patterns and structures in space-time. Current models have difficulty accounting for these interactions and unobserved structural complexity. A new approach may ask: why do the complex structures exist at all? Taking the view that the hydrology of a landscape has evolved along with its soils, ecology and geomorphology, we may ask if the hydrologic subsystem of a hillslope has a functional role in the maintenance of the overall system. This functional role may be expressed as an organizing principle - a constraint on possible ways that the hydrologic flowpaths may be organized such that the functional role is met. If a relationship can be established between an organizing principle and the structure of hydrologic flow-paths and storages, it can form the basis for developing closure relations at the hillslope scale that have meaningful relationships to the underlying dynamics. In this way, heterogeneity and complexity of hillslopes are no longer problems to be overcome, but rather are keys to making meaningful predictions. Formulating and testing organizing principles will necessarily require the synthesis of knowledge from many disciplines. One approach is to construct artificial hillslopes in a controlled environment, and use them to ask, given a set of observable constraints (climate, soil, ecologic and biogeochemical parameters) which structures and responses are "behavioral" - in the sense that they fulfill the function set by the organizing principle. Such artificial hillslopes will be constructed at

  18. 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.

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

    Science.gov (United States)

    Tan, Kwan Wee; Moore, David T; Saliba, Michael; Sai, Hiroaki; Estroff, Lara A; Hanrath, Tobias; Snaith, Henry J; Wiesner, Ulrich

    2014-05-27

    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.

  20. Identification, characterization and evolution of non-local quasi-Lagrangian structures in turbulence

    Institute of Scientific and Technical Information of China (English)

    Yue Yang

    2016-01-01

    The recent progress on non-local Lagrangian and quasi-Lagrangian structures in turbulence is reviewed. The quasi-Lagrangian structures, e.g., vortex surfaces in vis-cous flow, gas-liquid interfaces in multi-phase flow, and flame fronts in premixed combustion, can show essential Lagrangian following properties, but they are able to have topological changes in the temporal evolution. In addition, they can represent or influence the turbulent flow field. The challenges for the investigation of the non-local structures include their identification, characterization, and evolution. The improving understanding of the quasi-Lagrangian struc-tures is expected to be helpful to elucidate crucial dynamics and develop structure-based predictive models in turbulence.

  1. Structure evolution of poly(3-hexylthiophene) on Si wafer and poly(vinylphenol) sublayer.

    Science.gov (United States)

    Sun, Xiaoli; Ren, Zhongjie; Liu, Junteng; Takahashi, Isao; Yan, Shouke

    2014-07-01

    The structure evolution of P3HT thin films on Si wafer and PVPh covered Si wafer during heating, thermal annealing, and melt recrystallization processes has been studied in detail using X-ray analysis techniques. The effect of substrate on the crystallization behavior and interface structure of P3HT films was explored. For the P3HT films deposited on the Si substrate, it was found that the stability of P3HT crystals is orientation dependent. The crystals oriented with b-axis normal to the substrate, that is, a face-on molecular orientation, are less stable than those with the a-axis arranged normal to the substrate (side-on molecular orientation). Thermal annealing temperature plays an important role in the molecular structure of P3HT including crystal structure, film thickness, and surface roughness. After annealing at relatively high temperature, new crystals form during the cooling process accompanied by the shrinking of a-axis. Moreover, the melt recrystallization favors the formation of more stable P3HT crystals with side-on molecular orientation. The PVPh substrate does not affect the crystallization behavior of solution cast P3HT significantly but inhibits the formation of P3HT crystal with face-on molecular orientation. However, the interfacial morphology of P3HT and PVPh changes by annealing at elevated temperature. The P3HT/PVPh interface changes from a sharply defined one into a diffused one at around 160 °C. The PVPh sublayer inhibits the melt recrystallization of P3HT to some extent, leading to a slight expansion of the a-axis.

  2. Analysis of Pumphouse RCC Frame Structure for Soil Structure Interaction

    Directory of Open Access Journals (Sweden)

    Mr A.S. Thombare

    2016-06-01

    Full Text Available When structure is built on ground some elements of structure are direct contact with soil. When loads are applied on structure internal forces are developed in both the structure as well as in soil. It results in deformation of both the components which are independent to each other. This are called soil structure interaction. The analysis is done by using (Bentley STAAD.Pro V8i Version 2007 software. The analysis carried out been pump house structure R.C.C. frame structure find out shear force Z direction fixed support and fixed but support for different soil. It concluded that soil structure interaction more affected on fixed base. So overcome the effects of the soil structure interaction on the soft soil, it is important to design the structure to standard loading condition and interaction forces. Thus here concluded that pump house building should be design resist the maximum shear force in fixed base

  3. Monogamy, strongly bonded groups, and the evolution of human social structure.

    Science.gov (United States)

    Chapais, Bernard

    2013-01-01

    Human social evolution has most often been treated in a piecemeal fashion, with studies focusing on the evolution of specific components of human society such as pair-bonding, cooperative hunting, male provisioning, grandmothering, cooperative breeding, food sharing, male competition, male violence, sexual coercion, territoriality, and between-group conflicts. Evolutionary models about any one of those components are usually concerned with two categories of questions, one relating to the origins of the component and the other to its impact on the evolution of human cognition and social life. Remarkably few studies have been concerned with the evolution of the entity that integrates all components, the human social system itself. That social system has as its core feature human social structure, which I define here as the common denominator of all human societies in terms of group composition, mating system, residence patterns, and kinship structures. The paucity of information on the evolution of human social structure poses substantial problems because that information is useful, if not essential, to assess both the origins and impact of any particular aspect of human society.

  4. 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.

  5. Structure evolution of AZ61 magnesium alloy in SIMA process

    Institute of Scientific and Technical Information of China (English)

    YAN Hong; ZHANG Fa-yun; JIE Xiao-ping

    2005-01-01

    The effect of prior compressive deformation, isothermal temperature and holding time on the structure of AZ61 magnesium alloy fabricated by strain-induced melt activation(SIMA) processing was investigated. The specimens were subjected under deformation ratios of 0%, 22% and 40% and various heat treatment time and temperature regions. The results indicate that the ideal technological parameters of semi-solid AZ61 alloy produced with non-dendrites are recommended as 22% (prior compressive deformation), 595 ℃ (heat treatment temperature) and 40 min(time). The as-cast AZ61 magnesium alloy isn't fit for semi-solid forming.

  6. 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

  7. 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.

  8. 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.

  9. Impact origin of the Sudbury structure: Evolution of a theory

    Science.gov (United States)

    Lowman, Paul D., Jr.

    1992-01-01

    This paper reviews the origin, development, and present status of the widely accepted theory, proposed by Robert S. Dietz in 1962, that the Sudbury structure was formed by meteoritic or asteroidal impact. The impact theory for the origin of the Sudbury structure seems supported by a nearly conclusive body of evidence. However, even assuming an impact origin to be correct, at least three major questions require further study: (1) the original size and shape of the crater, before tectonic deformation and erosion; (2) the source of the melt now forming the Sudbury Igneous Complex; and (3) the degree, if any, to which the Ni-Cu-platinum group elements are meteoritic. The history of the impact theory illustrates several under-appreciated aspects of scientific research: (1) the importance of cross-fertilization between space research and terrestrial geology; (2) the role of the outsider in stimulating thinking by insiders; (3) the value of small science, at least in the initial stages of an investigation, Dietz's first field work having been at his own expense; and (4) the value of analogies (here, between the Sudbury Igneous Complex and the maria), which although incorrect in major aspects, may trigger research on totally new lines. Finally, the Sudbury story illustrates the totally unpredictable and, by implication, unplannable nature of basic research, in that insight to the origin of the world's then-greatest Ni deposit came from the study of tektites and the Moon.

  10. 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.

  11. 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....

  12. 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.

  13. THE FORMATION, EVOLUTION AND OPTIMAZATIONOF TERRITORIAL STRUCTURE IN THE SOUTHERN CHINA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    With the change of geopolitical pattern of the world, pacific rim area increases economic cooperation, instead of military antagonism. After reform and open to outside world, the southern China takes in an amount of investment from Hongkong, Macao and Taiwan, taking advantage of superior geo-environment and thus forms a topical model of core-periphery in the southern China. The core-periphery model in the southern China is territorially made of three parts: core area-Hong Kong, Macao and Taiwan; peripherial area Zhujiang delta; second core area-parts of Hunan Province, Jiangxi Province, Fujian Province and Hainan Province and Cuangxi Zhnang Autonomous Region. Its evolutional stage of this model can be divided into four stages: (1) the stage of polarization of core area; (2) the stage of the second core area strongly controlled by core area; (3) the transitional stage of the second area; (4) the stage of the southern China space integrity. Taking the core-periphrial model in the southern China as an integrity of interrelational and rational division, its whole functional organized system is “input-product-assemble-output”, core area is mainly then as the managed and transported center, the second area plays a product and productive control function and becomes center of manufacturing, study and development, periphrial area constructs as the center of material and raw material and the base of agricultural and side-line products. Based on the analysis of the formative structure, evolutional law and the design of territorial function, we suggust the way of territerial optimazation as follows: (1) establishing the large hinterland which takes Xijiang basin as its core; (2) construct the high and renewed technological corridor; (3) constructing stable and varied material and raw material base; (4) reinforcing the organization and adjustment and managment between core area,periphrial area and second periphrial area. (5) constucting the varied corridor among core area

  14. DNA secondary structures and epigenetic determinants of cancer genome evolution

    OpenAIRE

    2010-01-01

    An unstable genome is a hallmark of many cancers. It is unclear, however, whether some mutagenic features driving somatic alterations in cancer are encoded in the genome sequence and whether they can operate in a tissue-specific manner. We performed a genome-wide analysis of 663,446 DNA breakpoints associated with somatic copy-number alterations (SCNAs) from 2,792 cancer samples classified into 26 cancer types. Many SCNA breakpoints are spatially clustered in cancer genomes. We observed a sig...

  15. Kinematic Morphology of Large-scale Structure: Evolution from Potential to Rotational Flow

    CERN Document Server

    Wang, Xin; Aragon-Calvo, Miguel A; Neyrinck, Mark C; Eyink, Gregory L

    2013-01-01

    As an alternative way of describing 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 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. Before shell-crossing, different categories of potential flow are highly associated with 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 spatia...

  16. Time dependent couplings in the dark sector: from background evolution to nonlinear structure formation

    CERN Document Server

    Baldi, Marco

    2010-01-01

    We present a complete numerical study of cosmological models with a time dependent coupling between the dark energy component driving the present accelerated expansion of the Universe and the Cold Dark Matter (CDM) fluid. Depending on the functional form of the coupling strength, these models show a range of possible intermediate behaviors between the standard LCDM background evolution and the widely studied case of interacting dark energy models with a constant coupling. These different background evolutions play a crucial role in the growth of cosmic structures, and determine strikingly different effects of the coupling on the internal dynamics of nonlinear objects. By means of a suitable modification of the cosmological N-body code GADGET-2 we have performed a series of high-resolution N-body simulations of structure formation in the context of interacting dark energy models with variable couplings. Depending on the type of background evolution, the halo density profiles are found to be either less or more...

  17. Evolution of structural and optical properties in the course of thermal evolution of sol-gel derived cobalt-doped gahnite

    Energy Technology Data Exchange (ETDEWEB)

    Kurajica, S., E-mail: stankok@fkit.hr [University of Zagreb, Faculty of Chemical Engineering and Technology, Marulicev trg 19, HR-10000 Zagreb (Croatia); Tkalcec, E. [University of Zagreb, Faculty of Chemical Engineering and Technology, Marulicev trg 19, HR-10000 Zagreb (Croatia); Grzeta, B. [Division of Materials Physics, Ruder Boskovic Institute, Bijenicka 54, HR-10000 Zagreb (Croatia); Ivekovic, D. [University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, HR-10000 Zagreb (Croatia); Mandic, V. [University of Zagreb, Faculty of Chemical Engineering and Technology, Marulicev trg 19, HR-10000 Zagreb (Croatia); Popovic, J. [Division of Materials Physics, Ruder Boskovic Institute, Bijenicka 54, HR-10000 Zagreb (Croatia); Kranzelic, D. [University of Zagreb, Faculty of Chemical Engineering and Technology, Marulicev trg 19, HR-10000 Zagreb (Croatia)

    2011-02-17

    Research highlights: > Distribution of Co{sup 2+} ions in zinc cobalt aluminate lattice seats depend on Co loading. The green color of samples at lower temperatures is a consequence of partial oxidation of Co{sup 2+} ions and their accommodation in octahedral sites. Thermal treatment at higher temperatures promotes gradual change of color to blue, characteristic for tetrahedrally coordinated Co{sup 2+} ions. The spectra evolution could be interpreted as a progressive reduction of Co{sup 3+} to Co{sup 2+} ions at higher temperatures. - Abstract: Thermal evolution of sol-gel derived gahnite (ZnAl{sub 2}O{sub 4}) with 4, 8 and 12 at.% of Zn replaced with Co was studied by thermal analysis techniques (DTA/TGA), X-ray diffraction (XRD) and UV-vis diffuse reflectance spectroscopy (DRS). Zinc-cobalt spinel powders were produced by gel heat treatment at temperatures as low as 400 {sup o}C. Crystal structure was characterized using Rietveld refinement of X-ray diffraction patterns for the samples annealed at 800 {sup o}C, simultaneously with the analysis of diffraction line broadening. It was found out that the distribution of Co{sup 2+} ions in tetrahedral and octahedral sites of zinc cobalt aluminate crystal lattice, crystallite size and lattice strain depend on Co loading. The green color of samples thermally treated at T < 800 deg. C has been explained as a consequence of partial oxidation of Co{sup 2+} ions at lower temperatures and accommodation of Co{sup 3+} ions in octahedral sites. Thermal treatment at higher temperatures promote gradual change of color from green to blue, characteristic for tetrahedrally coordinated Co{sup 2+} ions. The spectra evolution could be interpreted as a progressive reduction of Co{sup 3+} to Co{sup 2+} ions at higher temperatures.

  18. Stochastic analysis of the time evolution of laminar-turbulent bands of plane Couette flow.

    Science.gov (United States)

    Rolland, Joran

    2015-11-01

    This article is concerned with the time evolution of the oblique laminar-turbulent bands of transitional plane Couette flow under the influence of turbulent noise. Our study is focused on the amplitude of modulation of turbulence (the bands). In order to guide the numerical study of the flow, we first perform an analytical and numerical analysis of a Stochastic Ginzburg-Landau (GL) equation for a complex order parameter. The modulus of this order parameter models the amplitude of modulation of turbulence. Firstly, we compute the autocorrelation function of said modulus once the band is established. Secondly, we perform a calculation of average and fluctuations around the exponential growth of the order parameter. This type of analysis is similar to the Stochastic Structural Stability Theory (S3T). We then perform numerical simulations of the Navier-Stokes equations in order to confront these predictions with the actual behaviour of the bands. Computation of the autocorrelation function of the modulation of turbulence shows quantitative agreement with the model: in the established band regime, the amplitude of modulation follows an Ornstein-Uhlenbeck process. In order to test the S3T predictions, we perform quench experiments, sudden decreases of the Reynolds number from uniform turbulence, in which modulation appears. We compute the average evolution of the amplitude of modulation and the fluctuations around it. We find good agreement between numerics and modeling. The average trajectory grows exponentially, at a rate clearly smaller than that of the formation of laminar holes. Meanwhile, the actual time evolution remains in a flaring envelope, centered on the average, and expanding at the same rate. These results provide further validation of the stochastic modeling for the time evolution of the bands for further studies. Besides, they stress on the difference between the oblique band formation and the formation of laminar holes.

  19. Fine structure of flare ribbons and evolution of electric currents

    CERN Document Server

    Sharykin, I N

    2014-01-01

    Emission of solar flares across the electromagnetic spectrum is often observed in the form of two expanding ribbons. The standard flare model explains the flare ribbons as footpoints of magnetic arcades, emitting due to interaction of energetic particles with the chromospheric plasma. However, the physics of this interaction and properties of the accelerated particles are still unknown. We present results of multiwavelength observations of C2.1 flare of August 15, 2013, observed with New Solar Telescope (NST) of Big Bear Solar Observatory, Solar Dynamics Observatory (SDO), GOES and FERMI spacecraft. The observations reveal previously unresolved sub-arcsecond structure of the flare ribbons in regions of strong magnetic field consisting from numerous small-scale bright knots. We observe red-blue asymmetry of H alpha flare ribbons with a width as small as 100 km. We discuss the relationship between the ribbons and vertical electric currents estimated from vector magnetograms, and show that Joule heating can be r...

  20. Halo formation and evolution: unification of structure and physical properties

    Science.gov (United States)

    Ernest, Allan D.; Collins, Matthew P.

    2016-08-01

    The assembly of matter in the universe proliferates a wide variety of halo structures, often with enigmatic consequences. Giant spiral galaxies, for example, contain both dark matter and hot gas, while dwarf spheroidal galaxies, with weaker gravity, contain much larger fractions of dark matter, but little gas. Globular clusters, superficially resembling these dwarf spheroidals, have little or no dark matter. Halo temperatures are also puzzling: hot cluster halos contain cooler galaxy halos; dwarf galaxies have no hot gas at all despite their similar internal processes. Another mystery is the origin of the gas that galaxies require to maintain their measured star formation rates (SFRs). We outline how gravitational quantum theory solves these problems, and enables baryons to function as weakly-interacting-massive-particles (WIMPs) in Lambda Cold Dark Matter (LCDM) theory. Significantly, these dark-baryon ensembles may also be consistent with primordial nucleosynthesis (BBN) and cosmic microwave background (CMB) anisotropies.

  1. Further Evidence for Cosmological Evolution of the Fine Structure Constant

    CERN Document Server

    Webb, J K; Flambaum, V V; Dzuba, V A; Barrow, John D; Churchill, C W; Prochaska, J X; Wolfe, A M

    2001-01-01

    We summarise the results of a search for time variability of the fine structure constant, alpha, using absorption systems in the spectra of distant quasars. Three large optical datasets and two 21cm/mm absorption systems provide four independent samples, spanning approximately 23% to 87% of the age of the universe. Each sample yields a negative Delta(alpha)/alpha (smaller alpha in the past) and the whole optical sample shows a 4-sigma deviation: Delta(alpha)/alpha = -0.72 +/- 0.18 x 10^{-5} over the redshift range 0.5 < z < 3.5. A comprehensive search for systematic effects reveals none which can explain our results. The only potentially significant systematic effects push Delta(alpha)/alpha towards positive values, i.e. our results would become more significant were we to correct for them.

  2. The structural evolution of carbonaceous material during metamorphism : a geothermometer

    Science.gov (United States)

    Beyssac, O.; Goffe, B.; Brunet, F.; Bollinger, L.; Avouac, J.; Rouzaud, J.

    2003-12-01

    With increasing metamorphic temperature, the organic matter present in sedimentary rocks is progressively transformed into graphite (graphitization). The degree of organization of this carbonaceous material (CM) as characterized by Raman spectroscopy (RSCM), can be used as a geothermometer which yields the maximum temperature reached during the metamorphic cycle (Beyssac et al., 2002). We used this RSCM geothermometer to map the maximum metamorphic temperatures through the Lesser Himalaya (LH) in Nepal. This study provides a large dataset (80 samples) to estimate uncertainty of this method and to ascertain its reliability by comparison with conventional petrological investigations. We show that the RSCM geothermometer might be used to detect inter-samples temperature variations as small as 10° C or so, but absolute temperatures are only loosely determined to +/- 50° C due to the uncertainty on the calibration. This successful application of the RSCM geothermometer confirms that, at the timescale of regional metamorphism (several My), the transformation of CM is mainly controlled by temperature. However, laboratory investigations suggest that, in addition to temperature, pressure should also play a role (Beyssac et al. 2003). As a matter of fact, high degree of organizations encountered in natural CM cannot be reproduced in laboratory without pressure, even at temperatures as high as 3000° C. In addition to the data acquired on natural CM, we will discuss laboratory experiments performed up to 8 GPa which show that (1) a few kbar of hydrostatic pressure are required to initiate microtextural and subsequent structural transformations within CM and (2) the overall effect of increasing pressure is to speed up graphitization process. Beyssac, O., Goffe, B., Chopin, C., and Rouzaud, J.N., 2002, Raman spectra of carbonaceous material in metasediments: a new geothermometer. Journal of Metamorphic Geology, 20, 859-871. Beyssac, O., Brunet, F., Petitet, J.P., Goffe, B

  3. 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

  4. Structure and Evolution of Pre-Main Sequence Stars

    CERN Document Server

    Schulz, Norbert S; Bautz, Mark W; Canizares, Claude C; Davis, John; Dewey, Dan; Huenemoerder, David P; Heilmann, Ralf; Houck, John; Marshall, Herman L; Nowak, Mike; Schattenburg, Mark; Audard, Marc; Drake, Jeremy; Gagne, Marc; Kastner, Joel; Kallman, Tim; Lautenegger, Maurice; Lee, Julia; Miller, Jon; Montmerle, Thierry; Mukai, Koji; Osten, Rachel; Parerels, Frits; Pollock, Andy; Preibisch, Thomas; Raymond, John; Reale, Fabio; Smith, Randall; Testa, Paola; Weintraub, David

    2009-01-01

    Low-mass pre-main sequence (PMS) stars are strong and variable X-ray emitters, as has been well established by EINSTEIN and ROSAT observatories. It was originally believed that this emission was of thermal nature and primarily originated from coronal activity (magnetically confined loops, in analogy with Solar activity) on contracting young stars. Broadband spectral analysis showed that the emission was not isothermal and that elemental abundances were non-Solar. The resolving power of the Chandra and XMM X-ray gratings spectrometers have provided the first, tantalizing details concerning the physical conditions such as temperatures, densities, and abundances that characterize the X-ray emitting regions of young star. These existing high resolution spectrometers, however, simply do not have the effective area to measure diagnostic lines for a large number of PMS stars over required to answer global questions such as: how does magnetic activity in PMS stars differ from that of main sequence stars, how do they ...

  5. Observational constraints on the structure and evolution of quasars

    Science.gov (United States)

    Kelly, Brandon C.

    2008-01-01

    I use X-ray and optical data to investigate the structure of quasars, and its dependence on luminosity, redshift, black hole mass, and Eddington ratio. In order to facilitate my work, I develop new statistical methods of accounting for measurement error, non-detections, and survey selection functions. The main results of this thesis follow. (1) The statistical uncertainty in the broad line mass estimates can lead to significant artificial broadening of the observed distribution of black hole mass. (2) The z = 0.2 broad line quasar black hole mass function falls off approximately as a power law with slope ~ 2 for M BH [Special characters omitted.] 10 8 [Special characters omitted.] . (3) Radio-quiet quasars become more X-ray quiet as their optical/UV luminosity, black hole mass, or Eddington ratio increase, and more X-ray loud at higher redshift. These correlations imply that quasars emit a larger fraction of their bolometric luminosity through the accretion disk component, as compared to the corona component, as black hole mass and Eddington ratio increase. (4) The X- ray spectral slopes of radio-quiet quasars display a non-monotonic trend with Eddington ratio, where the X-ray continuum softens with increasing Eddington ratio until L/L Edd ~ 0.3, and then begins to harden. This observed non- monotonic trend may be caused by a change in the structure of the disk/corona system at L/L Edd ~ 0.3, possibly due to increased radiation pressure. (5) The characteristic time scales of quasar optical flux variations increase with increasing M BH , and are consistent with disk orbital or thermal time scales. In addition the amplitude of short time scale variability decreases with increasing M BH . I interpret quasar optical light curves as being driven by thermal fluctuations, which in turn are driven by some other underlying stochastic process with characteristic time scale long compared to the disk thermal time scale. The stochastic model I use is able to explain both short

  6. 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.

  7. 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.

  8. Diverse Structural Evolution at z > 1 in Cosmologically Simulated Galaxies

    CERN Document Server

    Snyder, Gregory F; Moody, Christopher; Peth, Michael; Freeman, Peter; Ceverino, Daniel; Primack, Joel; Dekel, Avishai

    2014-01-01

    From mock Hubble Space Telescope images, we quantify non-parametric statistics of galaxy morphology, thereby predicting the emergence of relationships among stellar mass, star formation, and observed rest-frame optical structure at 1 10^10 M_sun contain relatively more disc-dominated light profiles than those with lower mass, reflecting significant disc brightening in some haloes at 1 10^10 M_sun. We analyze a cosmological major merger at z~1.5 and find that the newly proposed MID morphology diagnostics trace later stages while G-M20 trace earlier ones. MID is sensitive also to clumpy star-forming discs. The observability time of typical MID-enhanced events in our simulation sample is less than 100 Myr. A larger sample of cosmological assembly histories may be required to calibrate such diagnostics in the face of their sensitivity to viewing angle, segmentation algorithm, and various phenomena such as clumpy star formation and minor mergers.

  9. Structure and evolution of low-mass Population II stars

    Science.gov (United States)

    Montalbán, J.; D'Antona, F.; Mazzitelli, I.

    2000-08-01

    The focus of the present paper is on the detailed description of the internal structures of low mass, population II stars, to clarify some issues about these stellar models and, mainly, their present reliability for observational comparisons. We then explore 1) the role of the local convective model; 2) the differences between "grey" and "non grey" models, and between models in which the photospheric boundary conditions are set at different optical depths (τph = 3 or 100); 3) the role of the equation of state (EoS), both in the atmospheric models and in the interior. One of the major conclusions of the paper is a cautionary note about the usage of the additive volume law in EoS calculations. The dependence of the HR diagram locations and mass luminosity relations on metal and helium content are also discussed. A few comparisons with globular cluster stars show that: 1) general consistency of distance scales and morphologies in the HR diagram is found, when comparing ground based measurements in the Johnson B and V bands and observations in the HST bands; 2) a discrepancy between models and observations may exist for more metal rich clusters; 3) the plausible hypothesis that the mass function in the globular cluster NGC 6397 behaves smoothly until the lower limit of the main sequence poses constraints on the mass-luminosity relation at the lowest end of the main sequence. The evolutionary tracks are available at the WEB location http://www.mporzio.astro.it.

  10. 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.

  11. Multidimensional analysis of Drosophila wing variation in Evolution Canyon

    Indian Academy of Sciences (India)

    Vincent Debat; Raphael Cornette; Abraham B. Koral; Eviatar Nevo; David Soulet; Jean R. David

    2008-12-01

    Environmental stress has been suggested to be a major evolutionary force, both through inducing strong selection and because of its direct impact on developmental buffering processes that alter the evolvability of organisms. In particular, temperature has attracted much attention because of its importance as an ecological feature and the relative ease with which it can be experimentally manipulated in the lab. Evolution Canyon, Lower Nahal Oren, Israel, is a well studied natural site where ecological parameters are suspected to drive evolutionary differentiation. In this study, using Drosophila melanogaster isofemale lines derived from wild flies collected on both slopes of the canyon, we investigated the effect of developmental temperature upon the different components of phenotypic variation of a complex trait: the wing. Combining geometric and traditional morphometrics, we find only limited evidence for a differentiation among slopes. Investigating simultaneously phenotypic plasticity, genetic variation among isofemale lines, variation among individuals and fluctuating asymmetry, we could not identify a consistent effect of the stressful conditions encountered on the south facing slope. The prevailing structuring effect is that of the experimentally manipulated temperature which clearly influences wing mean size and shape. Variability, in contrast, is not consistently affected by temperature. Finally, we investigated the specific relationship between individual variation and fluctuating asymmetry. Using metric multi-dimensional scaling we show that the related patterns of wing shape variation are not identical, supporting the view that the underlying developmental processes are to a certain extent different.

  12. An Analysis on a Negotiation Model Based on Multiagent Systems with Symbiotic Learning and Evolution

    Science.gov (United States)

    Hossain, Md. Tofazzal

    This study explores an evolutionary analysis on a negotiation model based on Masbiole (Multiagent Systems with Symbiotic Learning and Evolution) which has been proposed as a new methodology of Multiagent Systems (MAS) based on symbiosis in the ecosystem. In Masbiole, agents evolve in consideration of not only their own benefits and losses, but also the benefits and losses of opponent agents. To aid effective application of Masbiole, we develop a competitive negotiation model where rigorous and advanced intelligent decision-making mechanisms are required for agents to achieve solutions. A Negotiation Protocol is devised aiming at developing a set of rules for agents' behavior during evolution. Simulations use a newly developed evolutionary computing technique, called Genetic Network Programming (GNP) which has the directed graph-type gene structure that can develop and design the required intelligent mechanisms for agents. In a typical scenario, competitive negotiation solutions are reached by concessions that are usually predetermined in the conventional MAS. In this model, however, not only concession is determined automatically by symbiotic evolution (making the system intelligent, automated, and efficient) but the solution also achieves Pareto optimal automatically.

  13. Electronic- and band-structure evolution in low-doped (Ga,Mn)As

    OpenAIRE

    Yastrubchak, O.; J. Sadowski; Krzyzanowska, H.; Gluba, L.; Zuk, J.; Domagala, J. Z.; Andrearczyk, T.; Wosinski, T.

    2013-01-01

    Modulation photoreflectance spectroscopy and Raman spectroscopy have been applied to study the electronic- and band-structure evolution in (Ga,Mn)As epitaxial layers with increasing Mn doping in the range of low Mn content, up to 1.2%. Structural and magnetic properties of the layers were characterized with high-resolution X-ray diffractometry and SQUID magnetometery, respectively. The revealed results of decrease in the band-gap transition energy with increasing Mn content in very low-doped ...

  14. 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...... refinements, transmission electron microscopy, and Mossbauer spectroscopy. It is found that a change of magnetic structure from an antiferromagnetic to a ferrimagnetic (or ferromagnetic) structure occurs in the milled samples. This change is correlated with the redistribution of the cations, Zn and Fe...

  15. Simulated evolution of the dark matter large-scale structure of the Universe

    Science.gov (United States)

    Demiański, M.; Doroshkevich, A.; Pilipenko, S.; Gottlöber, S.

    2011-07-01

    We analyse the evolution of the basic properties of the simulated elements of the large-scale structure of the Universe (LSS) formed by dark matter (DM), and we confront it with the observed evolution of the Lyman α forest. In three high-resolution simulations, we have selected samples of compact DM clouds of moderate overdensity. Clouds are selected at redshifts 0 ≤z≤ 3 with the minimal spanning tree technique. The main properties of the clouds selected in this way are analysed in three-dimensional space and with the core-sampling approach. This allows us to compare estimates of the DM LSS evolution obtained with two different techniques, and to clarify some important aspects of the LSS evolution. In both cases, we find that regular redshift variations of the mean characteristics of the DM LSS are accompanied only by small variations of their probability distribution functions (PDFs), which indicates the self-similar characteristic of the DM LSS evolution. A high degree of relaxation of DM particles, compressed within the LSS, is found along the shortest principal axis of the clouds. We see that the internal structure of the selected clouds depends upon the mass resolution and scale of the perturbations achieved in the simulations. It is found that the low-mass tail of the PDFs of the LSS characteristics depends upon the procedure of cloud selection.

  16. 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.

  17. 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.

  18. Tracing specific synonymous codon-secondary structure correlations through evolution.

    Science.gov (United States)

    Oresic, Matej; Dehn, Michael; Korenblum, Daniel; Shalloway, David

    2003-04-01

    We previously showed that GAU codons are preferred (relative to synonymous GAC codons) for encoding aspartates specifically at the N-termini of alpha-helices in human, but not in E. coli, proteins. To test if this difference reflected a general difference between eucaryotes and procaryotes, we now extended the analysis to include the proteins and coding sequences of mammals, vertebrates, S. cerevisiae, and plants. We found that the GAU-alpha-helix correlation is also strong in non-human mammalian and vertebrate proteins but is much weaker or insignificant in S. cerevisiae and plants. The vertebrate correlations are of sufficient strength to enhance alpha-helix N-terminus prediction. Additional results, including the observation that the correlation is significantly enhanced when proteins that are known to be correctly expressed in recombinant procaryotic systems are excluded, suggest that the correlation is induced at the level of protein translation and folding and not at the nucleic acid level. To the best of our knowledge, it is not explicable by the canonical picture of protein expression and folding, suggesting the existence of a novel evolutionary selection mechanism. One possible explanation is that some alpha-helix N-terminal GAU codons may facilitate correct co-translational folding in vertebrates.

  19. 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

  20. Genome-Wide Analysis of Human Metapneumovirus Evolution

    Science.gov (United States)

    Kim, Jin Il; Park, Sehee; Lee, Ilseob; Park, Kwang Sook; Kwak, Eun Jung; Moon, Kwang Mee; Lee, Chang Kyu; Bae, Joon-Yong; Park, Man-Seong; Song, Ki-Joon

    2016-01-01

    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. PMID:27046055

  1. 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.

  2. 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.

  3. Dynamical evolution of the surface microrelief under multiple-pulse-laser irradiation: An analysis based on surface-scattered waves

    Science.gov (United States)

    Barborica, A.; Mihailescu, I. N.; Teodorescu, V. S.

    1994-03-01

    We introduce a theoretical analysis of the temporal and spatial evolution of the surface topography of solids following interference between incident and scattered pulsed laser beams. The essential role played by the nonlinear delayed feedback in the laser-radiation-surface system is considered. We show that it finally determines the surface topography evolution from pulse to pulse. In order to complete the analysis, numerical calculations have been conducted under the hypothesis of strong attenuation of laser radiation into the sample and of a limited heat diffusion during the action of a laser pulse. We predict an evolution from very simple to complex (chaotic) structures under multiple-pulse-laser irradiation of solid surfaces. This evolution is determined by some key irradiation parameters; initial surface microrelief, incident laser intensity, and the number of applied laser pulses. Experiments were performed in order to check the main predictions of the theoretical analysis. The system of transversal excited atmospheric pressure-CO2 laser radiation (λ=10.6 μm)-interacting with fused silica was chosen as appropriate for performing test experiments. Optical microscopy studies of laser-treated zones evidenced special modifications of the surface topography in good accordance with the conclusions following from the theoretical analysis. The theoretical analysis is also in good agreement with some available data from the literature, at the same time providing a coherent interpretation of previously unexplained behaviors.

  4. Morphological diversity and evolution of egg and clutch structure in amphibians

    Science.gov (United States)

    Altig, Ronald; McDiarmid, Roy W.

    2007-01-01

    The first part of this synthesis summarizes the morphology of the jelly layers surrounding an amphibian ovum. We propose a standard terminology and discuss the evolution of jelly layers. The second part reviews the morphological diversity and arrangement of deposited eggs?the ovipositional mode; we recognize 5 morphological classes including 14 modes. We discuss some of the oviductal, ovipositional, and postovipositional events that contribute to these morphologies. We have incorporated data from taxa from throughout the world but recognize that other types will be discovered that may modify understanding of these modes. Finally, we discuss the evolutionary context of the diversity of clutch structure and present a first estimate of its evolution.

  5. Time evolution of electron structure in femtosecond heated warm dense molybdenum.

    Science.gov (United States)

    Recoules, V.; Dorchies, F.; Bouchet, J.; Fourment, C.; Leguay, P. M.; Cho, B. I.; Engelhorn, K.; Nakatsutsumi, M.; Ozkan, C.; Tshentscher, T.; Harmand, M.; Toleikis, S.; Stormer, M.; Galtier, E.; Lee, H. J.; Nagler, B.; Heimann, P. A.; Gaudin, J.

    2015-11-01

    The time evolution of the electron structure is investigated in a molybdenum foil heated up to the warm dense matter regime by a femtosecond laser pulse, through time-resolved XANES spectroscopy. Spectra are measured with independent control of temperature and density. They are successfully compared with ab initio quantum molecular dynamic calculations and an analytical model. We demonstrate that the observed white line in the L3-edge reveals the time evolution of the electron density of state from the solid to the hot (a few eV) and expanding liquid.

  6. Conservation of mRNA secondary structures may filter out mutations in Escherichia coli evolution.

    Science.gov (United States)

    Chursov, Andrey; Frishman, Dmitrij; Shneider, Alexander

    2013-09-01

    Recent reports indicate that mutations in viral genomes tend to preserve RNA secondary structure, and those mutations that disrupt secondary structural elements may reduce gene expression levels, thereby serving as a functional knockout. In this article, we explore the conservation of secondary structures of mRNA coding regions, a previously unknown factor in bacterial evolution, by comparing the structural consequences of mutations in essential and nonessential Escherichia coli genes accumulated over 40 000 generations in the course of the 'long-term evolution experiment'. We monitored the extent to which mutations influence minimum free energy (MFE) values, assuming that a substantial change in MFE is indicative of structural perturbation. Our principal finding is that purifying selection tends to eliminate those mutations in essential genes that lead to greater changes of MFE values and, therefore, may be more disruptive for the corresponding mRNA secondary structures. This effect implies that synonymous mutations disrupting mRNA secondary structures may directly affect the fitness of the organism. These results demonstrate that the need to maintain intact mRNA structures imposes additional evolutionary constraints on bacterial genomes, which go beyond preservation of structure and function of the encoded proteins.

  7. The evolution of alternative cryptic female choice strategies in age-structured populations.

    Science.gov (United States)

    Jones, Adam G

    2002-12-01

    Cryptic female choice is a potentially important aspect of the sexual selection process. According to the theory of sexual dialectics, postcopulation manipulation of relative male fertilization success can provide an avenue by which females can circumvent attempts by males to control female reproduction. Here I use stochastic models to investigate the evolution of cryptic female choice in populations with and without age structure. In populations without age structure, cryptic female choice will evolve only when (1) precopulatory mate choice by females is inefficient, (2) variation in male fitness is correlated with a trait upon which a female can base her choice of mates, and (3) the cost of multiple mating is not too high. In populations with age structure, similar conditions apply. However, selection sometimes favors females that employ alternative strategies of female choice at different ages. These results help to define the types of biological systems in which we should expect to see the evolution of cryptic female choice. They also illustrate that the evolution of choice strategies in females may be complex and may mirror in some important respects the evolution of alternative mating tactics in males.

  8. Design and analysis of heliostat support structure

    Energy Technology Data Exchange (ETDEWEB)

    Zang Chuncheng; Wang Zhifeng [Inst. of Electrical Engineering, CAS, BJ (China); Liu Xiaobing; Zhang Xiliang [Himin Solar Energy Group Co. Ltd, Dezhou, SD (China); Wang Yanzhong [Beijing Univ. of Aeronautics and Astronautics, BJ (China)

    2008-07-01

    The design method of the heliostat support structure with the aim of reducing the cost maximally is described in this paper. In order to guarantee the strength, stiffness and stability of the structure, dynamic performance and static performance including internal stress and distortion are analyzed by means of VSAP (Visual Structural Analysis Program) finite element computational software. Then the support structure is optimized on the basis of the analysis. (orig.)

  9. Evolution of basin and range structure in the Ruby Mountains and vicinity, Nevada

    Science.gov (United States)

    Blackwell, D. D.; Reese, N. M.; Kelley, S. A.

    Results from various age dating techniques, seismic reflection profiling hydrocarbon maturation studies, and structural analysis were used to evaluate the Cenozoic deformation in the Ruby Mountains and adjoining ranges (pinyon Range and Cortez Range) in Elko and Eureka Counties, Nevada. Age dating techniques used include potassium-argon ages of biotites from granites published by Kistler et al. (1981) and fission track ages from apatite and zircon. Fission track ages from apatite reflect a closing temperature of 100 plus or minus 20 deg C. Zircon fission track ages reflect a closing temperature of 175 plus or minus 25 deg C and potassium-argon ages from brotite reflect a closing temperature of 250 plus or minus 30 deg C. Thus these results allow a reasonably precise tracking of the evolution of the ranges during the Cenozoic. Seismic reflection data are available from Huntington Valley. Access to seismic reflection data directly to the west of the Harrison Pass Pluton in the central Ruby Mountains was obtained. In addition results are available from several deep exploration holes in Huntington Valley.

  10. 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 ...

  11. Design of Robust Optimal Fixed Structure Controller Using Self Adaptive Differential Evolution

    Science.gov (United States)

    Joe Amali, S. Miruna; Baskar, S.

    This paper presents a design of robust optimal fixed structure controller for systems with uncertainties and disturbance using Self Adaptive Differential Evolution (SaDE) algorithm. PID controller and second order polynomial structure are considered for fixed structure controller. The design problem is formulated as minimization of maximum value of real part of the poles subject to the robust stability criteria and load disturbance attenuation criteria. The performance of the proposed method is demonstrated with a test system. SaDE self adapts the trial vector generation strategy and crossover rate (CR) value during evolution. Self adaptive Penalty (SP) method is used for constraint handling. The results are compared with constrained PSO and mixed Deterministic/Randomized algorithms. It is shown experimentally that the SaDE adapts automatically to the best strategy and CR value. Performance of the SaDE-based controller is superior to other methods in terms of success rate, robust stability, and disturbance attenuation.

  12. The Structure and Evolution of Magnetized Cloud Cores in a Zero--Density Background

    CERN Document Server

    Curry, C L; Curry, Charles L.; Stahler, Steven W.

    2001-01-01

    Molecular-line observations of star-forming cloud cores indicate that they are not the flattened structures traditionally considered by theory. Rather, they are elongated, perhaps in the direction of their internal magnetic field. We are thus motivated to consider the structure and evolution of axisymmetric, magnetized clouds that start from a variety of initial states, both flattened (oblate) and elongated (prolate). We devise a new technique, dubbed the $q$-method, that allows us to construct magnetostatic equilibria of any specified shape. We find, in agreement with previous authors, that the field lines in oblate clouds bend inward. However, those in prolate clouds bow outward, confining the structures through magnetic tension. We next follow the quasi-static evolution of these clouds via ambipolar diffusion, under the assumption of constant core mass. An oblate cloud either relaxes to a magnetically force-free sphere or, if sufficiently massive, flattens along its polar axis as its central density runs a...

  13. Fidelity of parent-offspring transmission and the evolution of social behavior in structured populations.

    Science.gov (United States)

    Débarre, F

    2017-02-28

    The theoretical investigation of how spatial structure affects the evolution of social behavior has mostly been done under the assumption that parent-offspring strategy transmission is perfect, i.e., for genetically transmitted traits, that mutation is very weak or absent. Here, we investigate the evolution of social behavior in structured populations under arbitrary mutation probabilities. We consider populations of fixed size N, structured such that in the absence of selection, all individuals have the same probability of reproducing or dying (neutral reproductive values are the all same). Two types of individuals, A and B, corresponding to two types of social behavior, are competing; the fidelity of strategy transmission from parent to offspring is tuned by a parameter μ. Social interactions have a direct effect on individual fecundities. Under the assumption of small phenotypic differences (implying weak selection), we provide a formula for the expected frequency of type A individuals in the population, and deduce conditions for the long-term success of one strategy against another. We then illustrate our results with three common life-cycles (Wright-Fisher, Moran Birth-Death and Moran Death-Birth), and specific population structures (graph-structured populations). Qualitatively, we find that some life-cycles (Moran Birth-Death, Wright-Fisher) prevent the evolution of altruistic behavior, confirming previous results obtained with perfect strategy transmission. We also show that computing the expected frequency of altruists on a regular graph may require knowing more than just the graph's size and degree.

  14. Truncated Moment Analysis of Nucleon Structure Functions

    Energy Technology Data Exchange (ETDEWEB)

    A. Psaker; W. Melnitchouk; M. E. Christy; C. E. Keppel

    2007-11-16

    We employ a novel new approach using "truncated" moments, or integrals of structure functions over restricted regions of x, to study local quark-hadron duality, and the degree to which individual resonance regions are dominated by leading twists. Because truncated moments obey the same Q^2 evolution equations as the leading twist parton distributions, this approach makes possible for the first time a description of resonance region data and the phenomenon of quark-hadron duality directly from QCD.

  15. Bayesian large-scale structure inference and cosmic web analysis

    CERN Document Server

    Leclercq, Florent

    2015-01-01

    Surveys of the cosmic large-scale structure carry opportunities for building and testing cosmological theories about the origin and evolution of the Universe. This endeavor requires appropriate data assimilation tools, for establishing the contact between survey catalogs and models of structure formation. In this thesis, we present an innovative statistical approach for the ab initio simultaneous analysis of the formation history and morphology of the cosmic web: the BORG algorithm infers the primordial density fluctuations and produces physical reconstructions of the dark matter distribution that underlies observed galaxies, by assimilating the survey data into a cosmological structure formation model. The method, based on Bayesian probability theory, provides accurate means of uncertainty quantification. We demonstrate the application of BORG to the Sloan Digital Sky Survey data and describe the primordial and late-time large-scale structure in the observed volume. We show how the approach has led to the fi...

  16. Formation and evolution of tweed structures on high-purity aluminum polycrystalline foils under cyclic tension

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, P. V., E-mail: kpv@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation); Vlasov, I. V. [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Sklyarova, E. A.; Smekalina, T. V. [National Research Tomsk Polytechnic University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    Peculiarities of formation and evolution of tweed structures on the surface of high-purity aluminum polycrystalline foils under cyclic tension were studied using an atom force microscope and a white light interferometer. Tweed structures of micron and submicron sizes were found on the foils at different number of cycles. In the range of 42,000 < N < 95,000 cycles destruction of tweed patterns is observed, which leads to their disappearance from the surface of the foils. Formation of tweed structures of various scales is discussed in terms of the Grinfeld instability.

  17. Formation and evolution of tweed structures on high-purity aluminum polycrystalline foils under cyclic tension

    Science.gov (United States)

    Kuznetsov, P. V.; Vlasov, I. V.; Sklyarova, E. A.; Smekalina, T. V.

    2015-10-01

    Peculiarities of formation and evolution of tweed structures on the surface of high-purity aluminum polycrystalline foils under cyclic tension were studied using an atom force microscope and a white light interferometer. Tweed structures of micron and submicron sizes were found on the foils at different number of cycles. In the range of 42,000 < N < 95,000 cycles destruction of tweed patterns is observed, which leads to their disappearance from the surface of the foils. Formation of tweed structures of various scales is discussed in terms of the Grinfeld instability.

  18. Analysis of piezoelectric structures and devices

    CERN Document Server

    Chen, Weiqiu; Wang, Ji

    2013-01-01

    This edited work covers piezoelectric materials in the form of beams, plates, shells, and other structural components in modern devices and structures. Applications are frequency control and detection functions in resonators, sensors, actuators, oscillations, and other smart and intelligent structures. The contributions cover novel methods for the analysis of piezoelectric structures including wave propagation, high frequency vibration, material characterization, and optimization of structures. Understanding of these methods is increasingly important in the design and modelling of next generat

  19. Hydrophobic Core Variations Provide a Structural Framework for Tyrosine Kinase Evolution and Functional Specialization.

    Science.gov (United States)

    Mohanty, Smita; Oruganty, Krishnadev; Kwon, Annie; Byrne, Dominic P; Ferries, Samantha; Ruan, Zheng; Hanold, Laura E; Katiyar, Samiksha; Kennedy, Eileen J; Eyers, Patrick A; Kannan, Natarajan

    2016-02-01

    Protein tyrosine kinases (PTKs) are a group of closely related enzymes that have evolutionarily diverged from serine/threonine kinases (STKs) to regulate pathways associated with multi-cellularity. Evolutionary divergence of PTKs from STKs has occurred through accumulation of mutations in the active site as well as in the commonly conserved hydrophobic core. While the functional significance of active site variations is well understood, relatively little is known about how hydrophobic core variations contribute to PTK evolutionary divergence. Here, using a combination of statistical sequence comparisons, molecular dynamics simulations, mutational analysis and in vitro thermostability and kinase assays, we investigate the structural and functional significance of key PTK-specific variations in the kinase core. We find that the nature of residues and interactions in the hydrophobic core of PTKs is strikingly different from other protein kinases, and PTK-specific variations in the core contribute to functional divergence by altering the stability and dynamics of the kinase domain. In particular, a functionally critical STK-conserved histidine that stabilizes the regulatory spine in STKs is selectively mutated to an alanine, serine or glutamate in PTKs, and this loss-of-function mutation is accommodated, in part, through compensatory PTK-specific interactions in the core. In particular, a PTK-conserved phenylalanine in the I-helix appears to structurally and functionally compensate for the loss of STK-histidine by interacting with the regulatory spine, which has far-reaching effects on enzyme activity, inhibitor sensing, and stability. We propose that hydrophobic core variations provide a selective advantage during PTK evolution by increasing the conformational flexibility, and therefore the allosteric potential of the kinase domain. Our studies also suggest that Tyrosine Kinase Like kinases such as RAF are intermediates in PTK evolutionary divergence inasmuch as they

  20. 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.

  1. 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.

  2. Structural style and tectonic evolution of the easternmost Gulf of Aden conjugate margins (Socotra - Southern Oman)

    Science.gov (United States)

    Nonn, Chloe; Leroy, Sylvie; Castilla, Raymi; de Clarens, Philippe; Lescanne, Marc

    2016-04-01

    domains, syn-tectonic structures and oblique accommodation zones to highlighted asymmetrical margins, characterized by strong lateral variability of crustal domains along and across strike. From external to internal domains of the margins and in between SHFZ and EGAFZ (first-order segment), this study details sharp necking domain and complex transition from hyperextended to oceanic crust characterized by: (i) hyperextended crust affected by volcanic extrusions; (ii) detachment faulting in the distal part of the margins allowing exhumation; (iii) volcanic constructions in the exhumation domain; (iv) a complex proto-oceanic crust. We highlight a significant second-order segmentation characterized by six N20°E trending transfer zones, limiting seven 25 - 60 km length segments and affecting necking domain as well as the ocean-continent transition. Based on interpretative cross-sections and detailed stratigraphic analysis, we discuss the complex temporal and spatial evolution of conjugate margins: (i) the margins segmentation and the relationship with structural inheritance (ii) the set-up of a long-offset detachment fault and the nature of the exhumed basement (iv) the origin and timing of magmatic events and the onset of proto-oceanic crust.

  3. 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...

  4. Genomic and protein structural maps of adaptive evolution of human influenza A virus to increased virulence in the mouse.

    Directory of Open Access Journals (Sweden)

    Jihui Ping

    Full Text Available Adaptive evolution is characterized by positive and parallel, or repeated selection of mutations. Mouse adaptation of influenza A virus (IAV produces virulent mutants that demonstrate positive and parallel evolution of mutations in the hemagglutinin (HA receptor and non-structural protein 1 (NS1 interferon antagonist genes. We now present a genomic analysis of all 11 genes of 39 mouse adapted IAV variants from 10 replicate adaptation experiments. Mutations were mapped on the primary and structural maps of each protein and specific mutations were validated with respect to virulence, replication, and RNA polymerase activity. Mouse adapted (MA variants obtained after 12 or 20-21 serial infections acquired on average 5.8 and 7.9 nonsynonymous mutations per genome of 11 genes, respectively. Among a total of 115 nonsynonymous mutations, 51 demonstrated properties of natural selection including 27 parallel mutations. The greatest degree of parallel evolution occurred in the HA receptor and ribonucleocapsid components, polymerase subunits (PB1, PB2, PA and NP. Mutations occurred in host nuclear trafficking factor binding sites as well as sites of virus-virus protein subunit interaction for NP, NS1, HA and NA proteins. Adaptive regions included cap binding and endonuclease domains in the PB2 and PA polymerase subunits. Four mutations in NS1 resulted in loss of binding to the host cleavage and polyadenylation specificity factor (CPSF30 suggesting that a reduction in inhibition of host gene expression was being selected. The most prevalent mutations in PB2 and NP were shown to increase virulence but differed in their ability to enhance replication and demonstrated epistatic effects. Several positively selected RNA polymerase mutations demonstrated increased virulence associated with >300% enhanced polymerase activity. Adaptive mutations that control host range and virulence were identified by their repeated selection to comprise a defined model for

  5. A conceptual approach to model co-evolution of urban structures

    CERN Document Server

    Schweitzer, Frank

    2016-01-01

    Urban structures encompass settlements, characterized by the spatial distribution of built-up areas, but also transportation structures, to connect these built-up areas. These two structures are very different in their origin and function, fulfilling complementary needs: (i) to access space, and (ii) to occupy space. Their evolution cannot be understood by looking at the dynamics of urban aggregations and transportation systems separately. Instead, existing built-up areas feed back on the further development of transportation structures, and the availability of the latter feeds back on the future growth of urban aggregations. To model this co-evolution, we propose an agent-based approach that builds on existing agent-based models for the evolution of trail systems and of urban settlements. The key element in these separate approaches is a generalized communication of agents by means of an adaptive landscape. This landscape is only generated by the agents, but once it exists, it feeds back on their further act...

  6. Evolution of the mammalian middle ear and jaw: adaptations and novel structures.

    Science.gov (United States)

    Anthwal, Neal; Joshi, Leena; Tucker, Abigail S

    2013-01-01

    Having three ossicles in the middle ear is one of the defining features of mammals. All reptiles and birds have only one middle ear ossicle, the stapes or columella. How these two additional ossicles came to reside and function in the middle ear of mammals has been studied for the last 200 years and represents one of the classic example of how structures can change during evolution to function in new and novel ways. From fossil data, comparative anatomy and developmental biology it is now clear that the two new bones in the mammalian middle ear, the malleus and incus, are homologous to the quadrate and articular, which form the articulation for the upper and lower jaws in non-mammalian jawed vertebrates. The incorporation of the primary jaw joint into the mammalian middle ear was only possible due to the evolution of a new way to articulate the upper and lower jaws, with the formation of the dentary-squamosal joint, or TMJ in humans. The evolution of the three-ossicle ear in mammals is thus intricately connected with the evolution of a novel jaw joint, the two structures evolving together to create the distinctive mammalian skull.

  7. Understanding the Evolution of Industrial Symbiosis Research : A Bibliometric and Network Analysis (1997-2012)

    NARCIS (Netherlands)

    Yu, Chang; Davis, Chris; Dijkema, Gerard P. J.

    2014-01-01

    This study analyzes the evolution of the research field of industrial symbiosis (IS). We elucidate its embedding in industrial ecology (IE), trace the development of research themes, and reveal the evolution of the research network through analysis of the core literature and journals that appeared f

  8. Wave analysis of the evolution of a single wave packet in supersonic boundary layer

    Science.gov (United States)

    Yermolaev, Yury G.; Yatskikh, Aleksey A.; Kosinov, Alexander D.; Semionov, Nickolay V.

    2016-10-01

    The evolution of the artificial wave packet in laminar flat-plate boundary layer was experimentally studied by hot-wire measurements at M=2. The localized disturbances were generated by pulse glow discharge. The wave analysis of evolution of wave packet was provided. It was found, that the most unstable waves are oblique, that consistent with results of linear theory.

  9. The Intelligent Use of Structural Analysis.

    Science.gov (United States)

    Grierson, Donald E.

    1983-01-01

    Discusses the use of sensitivity analysis in structural design computation. Such analysis can predict how response quantities will vary with given design changes. In addition, it can help student engineers better understand why and when particular structural analyses are or should be conducted. (JN)

  10. Macroeconomic Models used in the Structural Analysis of the Gross Domestic Product

    Directory of Open Access Journals (Sweden)

    Constantin Anghelache

    2013-07-01

    Full Text Available This paper describes a use case for macro economical models, the objective being the structural analysis of the Gross Domestic Product. The authors offer a snapshot on GDP evolution, the econometric models proposed for analysis are designed with the help of EViews software. Its performances are determined through the optics of the statistical tests.

  11. Nonlinear structural analysis using integrated force method

    Indian Academy of Sciences (India)

    N R B Krishnam Raju; J Nagabhushanam

    2000-08-01

    Though the use of the integrated force method for linear investigations is well-recognised, no efforts were made to extend this method to nonlinear structural analysis. This paper presents the attempts to use this method for analysing nonlinear structures. General formulation of nonlinear structural analysis is given. Typically highly nonlinear bench-mark problems are considered. The characteristic matrices of the elements used in these problems are developed and later these structures are analysed. The results of the analysis are compared with the results of the displacement method. It has been demonstrated that the integrated force method is equally viable and efficient as compared to the displacement method.

  12. 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)

  13. Damage Evolution in Composite Materials and Sandwich Structures Under Impulse Loading

    Science.gov (United States)

    Silva, Michael Lee

    Damage evolution in composite materials is a rather complex phenomenon. There are numerous failure modes in composite materials stemming from the interaction of the various constituent materials and the particular loading conditions. This thesis is concerned with investigating damage evolution in sandwich structures under repeated transient loading conditions associated with impulse loading due to hull slamming of high-speed marine craft. To fully understand the complex stress interactions, a full field technique to reveal stress or strain is required. Several full field techniques exist but are limited to materials with particular optical properties. A full field technique applicable to most materials is known as thermoelastic stress analysis (TSA) and reveals the variation in sum of principal stresses of a cyclically loaded sample by correlating the stresses to a small temperature change occurring at the loading frequency. Digital image correlation (DIC) is another noncontact full field technique that reveals the deformation field by tracking the motion of subsets of a random speckle pattern during the loading cycles. A novel experimental technique to aid in the study of damage progression that combines TSA and DIC simultaneously utilizing a single infrared camera is presented in this thesis. A technique to reliably perform DIC with an infrared (IR) camera is developed utilizing variable emissivity paint. The thermal data can then be corrected for rigid-body motion and deformation such that each pixel represents the same material point in all frames. TSA is then performed on this corrected data, reducing motion blur and increasing accuracy. This combined method with a single infrared camera has several advantages, including a straightforward experimental setup without the need to correct for geometric effects of two spatially separate cameras. Additionally, there is no need for external lighting in TSA as the measured electromagnetic radiation is emitted by the

  14. 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.)

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

    DEFF Research Database (Denmark)

    Tække, Jesper

    Luhmann (2002, 275), in his introduction to the systems theory, explicitly writs, that language is the mechanism behind the structural coupling between psychic – and social systems. This paper, in its first part, provides an interpretative and selective presentation of Luhmann’s argumentation...... 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...

  16. STRUCTURE EVOLUTION OF POLYMER CHAINS FOR NECKING FORMATION IN HIGH-SPEED FIBER SPINNING PROCESS

    Institute of Scientific and Technical Information of China (English)

    Hong Zheng; Wei Yu; Hong-bin Zhang; Chi-xing Zhou

    2006-01-01

    Finite element method is used to simulate the high-speed melt spinning process, based on the equation system proposed by Doufas et al. Calculation predicts a neck-like deformation, as well as the related profiles of velocity, diameter, temperature, chain orientation, and crystallinity in the fiber spinning process. Considering combined effects on the process such as flow-induced crystallization, viscoelasticity, filament cooling, air drag, inertia, surface tension and gravity, the simulated material flow behaviors are consistent with those observed for semi-crystalline polymers under various spinning conditions. The structure change of polymer coils in the necking region described by the evolution of conformation tensor is also investigated. Based on the relaxation mechanism of macromolecules in flow field different types of morphology change of polymer chains before and in the neck are proposed, giving a complete prospect of structure evolution and crystallization of semi-crystalline polymer in the high speed fiber spinning process.

  17. Optimization Modeling and Evolution Analysis of Beijing' s Industrial Structure under Energy Constraints%能源约束视角下北京市产业结构的优化模拟与演进分析

    Institute of Scientific and Technical Information of China (English)

    唐志鹏; 刘卫东; 付承伟; 武红

    2012-01-01

    利用北京市1987年-2007年的地区投入产出表,在能源消耗总量约束条件下构建了北京市1987年、1992年、1997年、2002年和2007年五个时期的投入产出优化模型,通过产业结构调整的手段来实现经济效益最大。通过五个历史时期的优化模拟,采用灰色关联度分析比较了各个历史时期的真实产业结构与优化产业结构的相似程度。研究表明:①北京市的产业结构调整的重点在于发展第三产业,包括批发和零售业、金融保险业和其他社会服务业部门;②除1987年外,北京市其他各时期工业调整方向需要降低大部分工业的比重,2002年和2007年则需要适度提高纺织服装鞋帽皮革羽绒制品业、通用专用设备制造业、交通运输设备制造业、电气机械及器材制造业和通信设备计算机及其他电子设备制造业的比重;③通过比较五个时期北京市产业结构的优化模拟,得出北京市1997年的产业结构优化程度最高,2002年则最低,同时数据显示北京市2002年以后的产业结构优化程度低于2002年以前,北京市产业结构优化仍旧具有较大的调整潜力。最后,提出了北京市产业结构未来调整的方向。%This study developed an input-output optimization model for Beijing under constraints of energy consumption,with the objective to maximize economic benefits by industrial structure adjustment in 1987,1992,1997,2002,and 2007,respectively,based on Beijing’s input-output tables.The similarity of the industrial structure between simulations and reality was analyzed by the grey interconnection degree method.Results show that 1)the emphasis of Beijing’s industrial structure adjustment is the development of the tertiary industry,involving increasing the proportions of three sectors,i.e.,wholesale and retail trade,finance and insurance,and other social services;2)Except 1987,the proportions of a majority of Beijing’s industries should be

  18. The Structure, Evolution, and Dynamics of Coastally Trapped Phenomena of Western North America

    Science.gov (United States)

    1998-01-01

    mesoscale model, version 5 (MM5).. Two papers are now near completion. 5. The PI and students have examined several gap flow situations in the Strait of...mountains during COAST IOP5 and the structural and evolution of gap flows in coastal terrain. To illustrate, the figure below shows a series of horizontal...cuts at increasing altitude across the Strait of Juan de Fuca during an easterly jet event. The shallow nature of the gap flow is apparent, as is its

  19. Internal Structure of Elementary Particle and Possible Deterministic Mechanism of Biological Evolution

    Directory of Open Access Journals (Sweden)

    Alexei V. Melkikh

    2004-03-01

    Full Text Available The possibility of a complicated internal structure of an elementary particle was analyzed. In this case a particle may represent a quantum computer with many degrees of freedom. It was shown that the probability of new species formation by means of random mutations is negligibly small. Deterministic model of evolution is considered. According to this model DNA nucleotides can change their state under the control of elementary particle internal degrees of freedom.

  20. 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.)

  1. Bi-Hamiltonian Structure of a Third-Order Nonlinear Evolution Equation on Plane Curve Motions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In the present paper, we identify the integrability of the third-order nonlinear evolution equation ut = (1/2)((uxx + u)-2)x in a Hamiltonian viewpoint. We prove that the recursion operator obtained by S. Yu. Sakovich is hereditary, and then deduce a bi-Hamiltonian structure of the equation by using some decomposition of the hereditary operator. A hierarchy associated to the equation is also shown.

  2. 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

  3. A Comprehensive study of Cavities on the Sun: Structure, Formation, and Evolution

    Science.gov (United States)

    Karna, Nishu; Zhang, Jie; Pesnell, William D.

    2016-05-01

    Coronal cavities are large-scale structures in the Sun's corona that are closely related with the long-term evolution of the magnetic field in the photosphere as well as associated with the energetic solar activity such as prominence eruptions and coronal mass ejections. They are observed as circular or elliptical-shaped relatively low-density dark regions above the solar limb in EUV, X-ray, and white-light coronal images. We used SDO/AIA limb synoptic maps, constructed from annuli above the solar limb, to systematically identify cavities. We observed 429 coronal prominence cavities between May 20, 2010 and Feb 1, 2015. We examined correlations between height, width, and length of the cavities. Based on the fitting of the shape of the cross section, we classified cavities in three types: prolate (38%), oblate (27%) and circular (35%). We found that the cavities of all shapes are common in shorter length while circular and oblate cavities are more common in the longer length. In general, we found that the overall 3-D topology of long stable cavities can be characterized as a long tube with an elliptical cross-section. Next, we investigated the pattern of cavity location and found that cavity systematically drifts towards the pole. We found that cavities form a belt by making a plot using SDO/HMI surface magnetogram similar to classical buttery diagram of sunspots, we call that the cavity belt. Our analysis showed that the cavity belts migrated towards higher latitude with time and the cavity belts disappeared after the polar magnetic field reversal. This result shows that cavity evolution provides new insight into the solar cycle. Moreover, we studied the underlying magnetic field of a circumpolar crown cavity (Mar 21, 2013- Oct 25, 2013) that was observed for several Carrington Rotations. Our results showed that the underlying polarity inversion line of cavities is formed between the trailing part of decayed active regions and the unipolar magnetic field in the

  4. 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.

  5. Small-angle neutron scattering study of structural evolution of different phases in protein solution

    Indian Academy of Sciences (India)

    V K Aswal; S Chodankar; J Kohlbrecher; R Vavrin; A G Wagh

    2008-10-01

    Small-angle neutron scattering (SANS) has been used to study the structural evolution of different phases in protein solution leading to crystallization, denaturation and gelation. The protein solution under crystallization mostly consists of monomers and dimers, and higher-mers are not observed as they are perhaps formed in very small numbers. The onset and the rate of crystallization strongly depend on the salt concentration. Protein denaturation on addition of surfactant occurs due to the formation of micelle-like clusters along the unfolded polypeptide chains of the protein. The structure of such protein{surfactant complex is found to be independent of the size of the micelles in their pure surfactant solutions. The structure of temperature-induced protein gels shows a fractal structure. Rheology of these gels shows a strong dependence on varying pH or protein concentration, whereas the structure of such gels is found to be similar.

  6. Structural Analysis of the Upper Internal Structure in PGSFR

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. H.; Koo, G. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    The upper internal structure (UIS) is a package of hardware suspended from the rotating plug to about 20 cm above the core assemblies. The functions of the UIS are to support shroud tubes containing the primary and secondary control rod drivelines and preserve critical alignments between these drivelines and the core lattice, under normal and off-normal conditions. In addition, the UIS produces sufficient coolant mixing to mitigate thermal transients to downstream components and provides an opening for the In-Vessel transfer machine to access inner core positions without interfacing with the control rod drive lines and the upper core instrumentation package. The radial position of the shroud tube is fixed by three horizontal guide plates and the lower guide plate is close to the core assemblies and is perforated to permit most of the core effluent to reach the region between guide plates. In this study, the primary stress analysis for dead weight was carried out and the thermal stress analysis considering the coolant temperature around the UIS was performed. In addition, the mode characteristics of the structure by the natural frequency analysis were evaluated. The structural analysis model is developed to evaluate the structural integrity of the UIS. The primary stress analysis, the thermal stress analysis and the natural frequency analysis for the UIS are performed, and the maximum stresses and displacements are evaluated. From the analysis results, it is confirmed that the large local stresses don't occur near the holes and through the wall thicknesses of the structure. In addition, the maximum temperature of the UIS is calculated as 545 .deg. C from the thermal analysis and the structure should be evaluated by the ASME design rules at a high temperature. In the future, the more detailed design will be performed by the high temperature evaluation procedure according to the ASME SEC. III, Div.5.

  7. Probabilistic structural analysis by extremum methods

    Science.gov (United States)

    Nafday, Avinash M.

    1990-01-01

    The objective is to demonstrate discrete extremum methods of structural analysis as a tool for structural system reliability evaluation. Specifically, linear and multiobjective linear programming models for analysis of rigid plastic frames under proportional and multiparametric loadings, respectively, are considered. Kinematic and static approaches for analysis form a primal-dual pair in each of these models and have a polyhedral format. Duality relations link extreme points and hyperplanes of these polyhedra and lead naturally to dual methods for system reliability evaluation.

  8. STATIC ANALYSIS OF CABLE STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    HUANG Yan; LAN Wei-ren

    2006-01-01

    Based on the nonlinear geometric relation between strain and displacement for flexible cable, the equilibrium equation under self-weight and influence of temperature was established and an analytical solution of displacement and tension distribution defined in Eulerian coordinate system was accurately obtained. The nonlinear algebraic equations caused by cable structure were solved directly using the modified Powell hybrid algorithm with high precision routine DNEQNE of Fortran. For example, a cable structure consisting of three cables jointly supported by a vertical spring and all the other ends fixed was calculated and compared with various methods by other scholars.

  9. 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.

  10. Structure analysis of growing network based on partial differential equations

    Directory of Open Access Journals (Sweden)

    Junbo JIA

    2016-04-01

    Full Text Available The topological structure is one of the most important contents in the complex network research. Therein the node degree and the degree distribution are the most basic characteristic quantities to describe topological structure. In order to calculate the degree distribution, first of all, the node degree is considered as a continuous variable. Then, according to the Markov Property of growing network, the cumulative distribution function's evolution equation with time can be obtained. Finally, the partial differential equation (PDE model can be established through distortion processing. Taking the growing network with preferential and random attachment mechanism as an example, the PDE model is obtained. The analytic expression of degree distribution is obtained when this model is solved. Besides, the degree function over time is the same as the characteristic line of PDE. At last, the model is simulated. This PDE method of changing the degree distribution calculation into problem of solving PDE makes the structure analysis more accurate.

  11. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    Energy Technology Data Exchange (ETDEWEB)

    Gargarella, P., E-mail: piter@ufscar.br [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rodovia Washington Luiz, Km 235, 13565-905 São Carlos, São Paulo (Brazil); Pauly, S.; Stoica, M.; Kühn, U. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Vaughan, G. [European Synchrotron Radiation Facilities, BP 220, 38043 Grenoble (France); Afonso, C. R. M. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rodovia Washington Luiz, Km 235, 13565-905 São Carlos, São Paulo (Brazil); Eckert, J. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Institut für Werkstoffwissenschaft, Technische Universität Dresden, D-01062 Dresden (Germany)

    2015-01-01

    The structural evolution of Ti{sub 50}Cu{sub 43}Ni{sub 7} and Ti{sub 55}Cu{sub 35}Ni{sub 10} metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni) phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  12. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    Science.gov (United States)

    Gargarella, P.; Pauly, S.; Stoica, M.; Vaughan, G.; M. Afonso, C. R.; Kühn, U.; Eckert, J.

    2015-01-01

    The structural evolution of Ti50Cu43Ni7 and Ti55Cu35Ni10 metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni) phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  13. Structural evolution in Ti-Cu-Ni metallic glasses during heating

    Directory of Open Access Journals (Sweden)

    P. Gargarella

    2015-01-01

    Full Text Available The structural evolution of Ti50Cu43Ni7 and Ti55Cu35Ni10 metallic glasses during heating was investigated by in-situ synchrotron X-ray diffraction. The width of the most intense diffraction maximum of the glassy phase decreases slightly during relaxation below the glass transition temperature. Significant structural changes only occur above the glass transition manifesting in a change in the respective peak positions. At even higher temperatures, nanocrystals of the shape memory B2-Ti(Cu,Ni phase precipitate, and their small size hampers the occurrence of a martensitic transformation.

  14. The Evolution of Unpolarized and Polarized Structure Functions at small $x$

    CERN Document Server

    Blümlein, Johannes; Vogt, A

    1996-01-01

    A survey is given of recent developments on the resummed small-$x$ evol= ution, in a framework based on the renormalization group equation, of non--singl= et and singlet structure functions in both unpolarized and polarized deep--inela= stic scattering. The available resummed anomalous dimensions are discussed for= all these cases, and the most important analytic and numerical results are compiled. The quantitative effects of these small-$x$ resummations on the evolution of the various parton densities and structure functions are presented, and their present uncertainties are investigated. An applicati= on to QED radiative corrections is given.

  15. STRUCTURE EVOLUTION OF THE CYLINDRICAL PHASE OF DIBLOCK COPOLYMERS IN FILMS

    Institute of Scientific and Technical Information of China (English)

    Hong-ge Tan; Zi-yu Wang; Wen-fang Zhu; Qing-gong Song; Hui Li; Cui-qin Bai

    2008-01-01

    In the weak segregation limit,the structure evolution of the hexagonal cylindrical phase of diblock copolymers in films was investigated.Employing the Landau-Brazovskii mean field theory,we obtained three amplitude parameters as functions of temperature,surface field strength and film thickness.By controlling confinement size and surface field strength,lamellae and undulated lamellae appear in the cylindrical bulk phase of diblock copolymers."Phase diagrams" of confinement-induced structures are constructed at different surface field strengths.The obtained theoretical results are in agreement with relevant theoretical and experimental results.

  16. Analysis of composite structural elements

    Directory of Open Access Journals (Sweden)

    A. Baier

    2010-12-01

    Full Text Available Purpose: The themes of the study are composite structural components. For this purpose have been designed and built several research positions.Design/methodology/approach: Using different structural materials to build new device components requires multiple tests of the components. Research posts were designed in the advanced graphical program CAx Siemens NX 7.5. Analysed samples were made from the glass fibre, aramid and carbon of various weights. Due to the specific use of composite materials it focuses on the elements in the form of plates and flat bars. For the examination of experimental strain gauge technique was used bead, the force sensor and displacement sensor. The experimental methods were compared with computer simulation using the FEM.Findings: The aim of this study was to determine the basic material constants and a comparison of the experimental method and the method of computer simulation.Research limitations/implications: Change the number of layers and how to connect the laminate with the steel plate changes mechanical properties of the structural component.Practical implications: The ultimate result will be knowledge on the different forms of laminates, such as material properties, the stresses in all layers, strain and comparing the results obtained by two methods.Originality/value: The expected outcome of the study will be the composition and method of joining composite laminate with a steel plate to the possible application in the repair and construction of structural elements of freight wagons.

  17. Seismic Structure and Geodynamic Evolution of the Lithosphere and Upper Mantle in the Pannonian - Carpathian Region

    Science.gov (United States)

    Houseman, G.; Stuart, G.; Dando, B.; Hetenyi, G.; Lorinczi, P.; Brueckl, E.; Hegedus, E.; Radovanovic, S.; Brisbourne, A.

    2009-04-01

    The Pannonian Basin is the largest of a group of Miocene-age extensional basins within the arc of the Alpine-Carpathian Mountain Ranges. These basins are extensional in origin, but the surrounding Carpathians result from sustained convergence during and since the period of active extension. A significant part of the mantle lithosphere here has been replaced, as gravitational instability caused an overturn of the upper mantle. The Carpathian Basins Project (CBP) is a major international broadband seismology experiment, supported by geodynamical modelling and designed to improve our understanding of the structure and evolution of the lithosphere and upper mantle beneath the Pannonian and Vienna Basins. Between 2005 and 2007 we deployed 56 portable broadband seismic stations in Austria, Hungary and Serbia, spanning the Vienna Basin and the western part of the Pannonian Basin. Arrival time residuals from teleseismic earthquakes are delayed by about 0.8 sec in the Vienna Basin and early by a similar amount in southwest Hungary. Tomographic inversion of the travel time residuals shows relatively fast P-wave velocities in the upper mantle beneath the western Pannonian Basin and slow P-wave velocities beneath the West Carpathians. Seismic anisotropy (SKS) measurements reveal an intriguing pattern of lithospheric anisotropy: in the north-west the fast direction is generally elongated EW, perpendicular to the shortening direction across the Alps. Across the Vienna Basin the fast direction is NW-SE, perpendicular to the major bounding fault systems. Across the Pannonian Basin the dominant fast direction is EW, but in several locations the vectors are rotated toward NW-SE. The Mid-Hungarian Line, a major strike-slip structure already clearly identified in the gravity field, also is associated with abrupt changes in the azimuth of lithospheric anisotropy. Receiver function analysis of the seismic discontinuity at 670 km shows significant structure on scales of order 100 km, and

  18. Kinematic Evolution of the Western Pyrenees Thrust Front From Paleomagnetic Analysis on its Foreland Basin.

    Science.gov (United States)

    Almar, Y.; Beamud, E.; Muñoz, J. A.; Garcés, M.; Murelaga, X.

    2007-12-01

    The Pyrenees is a collisional orogen formed during the Alpine orogeny. Its southwestern frontal thrust was originated as a result of the Cenozoic inversion of preexisting extensional faults. The emplacement of the frontal thrust in the Western Pyrenees generated a foreland basin, which locally accumulated more than 4,500 meters of Tertiary sediments. The kinematic evolution of the Western Pyrenees thrust front is poorly constrained due to the scarcity of reliable age constraints within the Tertiary sediments. However, the good exposure conditions of syntectonic continental deposits in its foreland basin makes it an excellent scenario to carry out paleomagnetic and structural studies in order to unravel the kinematic history, geometry and evolution of the thrust front. A magnetostratigraphic composite section along the continental basin infill was sampled covering up to 3,000 m of succession. Correlation of the local magnetostratigraphy with the GPTS was helped by a new mammal fossil locality found in continental sediments and attributed to the Agenian local biozone Y (MN2D). The cronostratigraphy of the tectosedimentary units, ranging from lower Oligocene (Cr12r) to lower Miocene, provides further constraints on the timing of two main tectosedimentary events recorded as major unconformities within the basin infill. From this study, sedimentation rates have been also obtained. The analysis of several paleomagnetic sites revealed that no vertical axes rotations occurred in the Tertiary sediments regardless superimposed folding with oblique axes could be observed, and the proximity of adjacent structures as the Estella diapir and the Pamplona fault. Finally, the analysis of the anisotropy of magnetic susceptibility together with collected sedimentary data suggests that magnetic fabrics record both, a depositional and tectonic fabric.

  19. A model for the evolution of the Earth's mantle structure since the Early Paleozoic

    Science.gov (United States)

    Zhang, Nan; Zhong, Shijie; Leng, Wei; Li, Zheng-Xiang

    2010-06-01

    Seismic tomography studies indicate that the Earth's mantle structure is characterized by African and Pacific seismically slow velocity anomalies (i.e., superplumes) and circum-Pacific seismically fast anomalies (i.e., a globally spherical harmonic degree 2 structure). However, the cause for and time evolution of the African and Pacific superplumes and the degree 2 mantle structure remain poorly understood with two competing proposals. First, the African and Pacific superplumes have remained largely unchanged for at least the last 300 Myr and possibly much longer. Second, the African superplume is formed sometime after the formation of Pangea (i.e., at 330 Ma) and the mantle in the African hemisphere is predominated by cold downwelling structures before and during the assembly of Pangea, while the Pacific superplume has been stable for the Pangea supercontinent cycle (i.e., globally a degree 1 structure before the Pangea formation). Here, we construct a proxy model of plate motions for the African hemisphere for the last 450 Myr since the Early Paleozoic using the paleogeographic reconstruction of continents constrained by paleomagnetic and geological observations. Coupled with assumed oceanic plate motions for the Pacific hemisphere, this proxy model for the plate motion history is used as time-dependent surface boundary condition in three-dimensional spherical models of thermochemical mantle convection to study the evolution of mantle structure, particularly the African mantle structure, since the Early Paleozoic. Our model calculations reproduce well the present-day mantle structure including the African and Pacific superplumes and generally support the second proposal with a dynamic cause for the superplume structure. Our results suggest that while the mantle in the African hemisphere before the assembly of Pangea is predominated by the cold downwelling structure resulting from plate convergence between Gondwana and Laurussia, it is unlikely that the bulk of

  20. Economic Analysis of Traffic Flow with an Evolution Equation

    Institute of Scientific and Technical Information of China (English)

    冯苏苇

    2005-01-01

    Based on two main hypotheses of traffic economical equilibrium and the relationship between traffic density and the demand, an evolution equation of traffic cost was proposed to describe the change of cost under decreasing toll. Economical explanation of the model and a numerical case were given to demonstrate the constraint between the marginal traffic demand and the flow velocity.

  1. Spatial structure, transmission modes and the evolution of viral exploitation strategies.

    Directory of Open Access Journals (Sweden)

    Thomas W Berngruber

    2015-04-01

    Full Text Available Spatial structure and local migration are predicted to promote the evolution of less aggressive host exploitation strategies in horizontally transmitted pathogens. Here we explore the effect of spatial structure on the evolution of pathogens that can use both horizontal and vertical routes of transmission. First, we analyse theoretically how vertical transmission can alter evolutionary trajectories and confirm that space can impede the spread of virulent pathogens. Second, we test this prediction using the latent phage λ which transmits horizontally and vertically in Escherichia coli populations. We show that the latent phage λ wins competition against the virulent mutant λcI857 in spatially structured epidemics, but loses when spatial structure is eroded. The vertical transmission of phage λ immunizes its local host pool against superinfection and prevents the spread of the virulent λcI857. This effect breaks down when mixing facilitates horizontal transmission to uninfected hosts. We thus confirm the importance of spatial structure for the evolutionary maintenance of prudent infection strategies in latent viruses.

  2. 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.

  3. The Impact of Anthropogenic Structures on the Delivery of Overwash and the Evolution of Barrier Islands

    Science.gov (United States)

    Rogers, L. J.; Moore, L. J.; Goldstein, E. B.

    2014-12-01

    Climate change-induced sea level rise and the potential for more intense, more frequent storms to occur in the future, will threaten the vitality of barrier islands by lowering their relative elevation and altering the frequency of overwash thereby leading to island narrowing and/or migration. High-density development (e.g., homes, condominiums, hotels, etc.) on many barrier islands may further increase island vulnerability by restricting delivery of sand to the subaerial island via overwash. To explore the potential future response of barrier islands to these factors, we analyzed state-wide pre and post-storm LiDAR surveys of New Jersey and North Carolina conducted in response to Hurricane Sandy (2012) and Nor'Ida (2009) to assess the influence of humans on storm-driven delivery of sand. We compared natural and developed environments of various foundational properties (commercial, residential - slab and residential - piling) by extracting and analyzing shore-perpendicular profiles. We tabulated overwash extent and thickness along each profile to determine the characteristic effects of different types of development in comparison to natural areas. We then used data derived from this profile analysis to inform the overwash component of a 2D barrier island model. Using this model, we assess the long-term (decadal to centurial) impacts of the interruption of sand delivery by anthropogenic structures on barrier island evolution. Through multiple numerical experiments we address a range of scenarios for sea level rise and changes in storminess. Early results suggest that commercial zones having a large frontage area pose the greatest threat to barrier island survivability under scenarios of rapid sea level rise.

  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. Analysis of feedback loops and robustness in network evolution based on Boolean models

    Directory of Open Access Journals (Sweden)

    Cho Kwang-Hyun

    2007-11-01

    Full Text Available Abstract Background Many biological networks such as protein-protein interaction networks, signaling networks, and metabolic networks have topological characteristics of a scale-free degree distribution. Preferential attachment has been considered as the most plausible evolutionary growth model to explain this topological property. Although various studies have been undertaken to investigate the structural characteristics of a network obtained using this growth model, its dynamical characteristics have received relatively less attention. Results In this paper, we focus on the robustness of a network that is acquired during its evolutionary process. Through simulations using Boolean network models, we found that preferential attachment increases the number of coupled feedback loops in the course of network evolution. Whereas, if networks evolve to have more coupled feedback loops rather than following preferential attachment, the resulting networks are more robust than those obtained through preferential attachment, although both of them have similar degree distributions. Conclusion The presented analysis demonstrates that coupled feedback loops may play an important role in network evolution to acquire robustness. The result also provides a hint as to why various biological networks have evolved to contain a number of coupled feedback loops.

  6. 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, includi

  7. {sup 3}He retention and structural evolution in erbium tritides: Phase and aging effects

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X.S., E-mail: zlxs77@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Thin Film Centre, Scottish Universities Physics Alliance (SUPA), University of West of Scotland, Paisley PA1 2BE, Scotland (United Kingdom); Zhang, L.; Wang, W.D.; Liu, Q. [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Peng, S.M., E-mail: pengshuming@caep.cn [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Ding, W.; Long, X.G.; Cheng, G.J.; Liang, J.H. [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900 (China); Fu, Y.Q. [Thin Film Centre, Scottish Universities Physics Alliance (SUPA), University of West of Scotland, Paisley PA1 2BE, Scotland (United Kingdom)

    2015-06-15

    Highlights: • Effects of phase changes on {sup 3}He retention of Er tritide films were investigated. • The α phase in Er tritide films had no apparent effect on {sup 3}He release/retention. • Tritium content in the β phase showed significant effects on {sup 3}He retention. • Evolution of {sup 3}He in the β phase was apparently influenced by the γ phase. • Effects of phase changes on structure evolution of Er tritides were investigated. - Abstract: Effects of phase changes on {sup 3}He release/retention and crystal lattice evolution during aging of erbium (Er) tritide films were investigated using X-ray diffraction. The contents of α phase and γ phase in the Er tritide films showed significant different effects on {sup 3}He release/retention. The initial tritium stoichiometry or excess tritium atoms accommodated in the octahedral sites and the microstructure (i.e., the texture and Er{sub 2}O{sub 3} oxide inclusions) played an important role for the {sup 3}He release and the evolution of {sup 3}He bubbles in the β phase Er tritide films. In the β + γ region, evolution of {sup 3}He in the β phase was apparently influenced by the γ phase, which could result in a strongly anisotropic lattice dilation and an earlier inflection point of the expansion rate of (1 1 1) lattice parameter. A preferred occupation of {sup 3}He in basal plane of the hexagonal γ phase and the lattice expansion along the hexagonal direction were identified.

  8. Driving electrocatalytic activity by interface electronic structure control in a metalloprotein hybrid catalyst for efficient hydrogen evolution.

    Science.gov (United States)

    Behera, Sushant Kumar; Deb, Pritam; Ghosh, Arghya

    2016-08-17

    The rational design of metalloprotein hybrid structures and precise calculations for understanding the role of the interfacial electronic structure in regulating the HER activity of water splitting sites and their microscopic effect for obtaining robust hydrogen evolution possess great promise for developing highly efficient nano-bio hybrid HER catalysts. Here, we employ high-accuracy linear-scaling density functional theory calculations using a near-complete basis set and a minimal parameter implicit solvent model within the self-consistent calculations, on silver (Ag) ions assimilated on bacteriorhodopsin (bR) at specific binding sites. Geometry optimization indicates the formation of active sites at the interface of the metalloprotein complex and the density of states reflects the metallic nature of the active sites. The reduced value of the canonical orbital gap indicates the state of dynamic nature after Ag ion assimilation on active sites and smooth electron transfer. These incorporated active protein sites are more efficient in electrolytic splitting of water than pristine sites due to their low value of Gibbs free energy for the HER in terms of hydrogen coverages. Volcano plot analysis and the free energy diagram are compared for understanding the hydrogen evolution efficiency. Moreover, the essential role of the interfacial electronic properties in regulating the HER catalytic activity of water splitting sites and enhancing the efficiency is elucidated.

  9. Thermal and structural analysis of Hermes

    Science.gov (United States)

    Petiau, C.

    1989-08-01

    After a brief recap of Hermes TPS and structure principles, we present the organization of thermal and structural analysis of the Hermes project, and we describe the way to resolve the problems of connections between calculations performed by the different Hermes partners. We describe in detail the interactions between the general model of TPS, used for global dimensioning of insulation, and refined thermal models giving an accurate temperature map inside details of "hot" and "cold" structures. The organization for structural analysis is based on a finite element general model which supports preliminary design, loads and vibration analyses. Boundary conditions for refined subpart analyses are cut to size, into the general model by a super element technique. This process involves the use by all partners of efficient computer codes, in the field of structural analysis and optimization integrated with CAD; for this Dassault proposes as a reference: the CATIA-ELFINI system.

  10. 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.

  11. Evolution of eutectic structures in Al-Zn-Mg-Cu alloys during heat treatment

    Institute of Scientific and Technical Information of China (English)

    FAN Xi-gang; JIANG Da-ming; MENG Qing-chang; ZHANG Bao-you; WANG Tao

    2006-01-01

    The evolution of the eutectic structures in the alloys with different copper contents during heat treatment was studied by scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and differential scanning calorimetry(DSC). The as cast microstructures involve α(Al), eutectic(α(Al) + Mg(Al, Cu, Zn)2) and Al7Cu2Fe. The Al2CuMg particles form during heat treatment. The volume of coarse phases decreases quickly in the initial 12 h during heat treatment. The volume of coarse phases change a little at 400 and 420 ℃. Copper content has a great influence on the evolution of the eutectic. The coarse phases dissolve slowly in alloy with higher copper content.

  12. Intron phase correlations and the evolution of the intron/exon structure of genes.

    Science.gov (United States)

    Long, M; Rosenberg, C; Gilbert, W

    1995-01-01

    Two issues in the evolution of the intron/exon structure of genes are the role of exon shuffling and the origin of introns. Using a large data base of eukaryotic intron-containing genes, we have found that there are correlations between intron phases leading to an excess of symmetric exons and symmetric exon sets. We interpret these excesses as manifestations of exon shuffling and make a conservative estimate that at least 19% of the exons in the data base were involved in exon shuffling, suggesting an important role for exon shuffling in evolution. Furthermore, these excesses of symmetric exons appear also in those regions of eukaryotic genes that are homologous to prokaryotic genes: the ancient conserved regions. This last fact cannot be explained in terms of the insertional theory of introns but rather supports the concept that some of the introns were ancient, the exon theory of genes. PMID:8618928

  13. 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)

  14. Evolution and mechanism of the periodical structures formed on Ti plate under femtosecond laser irradiation

    Science.gov (United States)

    Liu, Dong; Chen, Chuansong; Man, Baoyuan; Meng, Xue; Sun, Yanna; Li, Feifei

    2016-08-01

    This work investigates the femtosencond laser (fs-laser) induced periodical surface structures (FLIPSS) on titanium plate including the concentric rings, microgrooves and subwavelength ripples. The evolution of the three types of the structures at different laser fluence and shot number is investigated experimentally in detail. The competition mechanisms exist among the different FLIPSS. A processing window for each resulting FLIPSS is obtained. In order to give an overall understanding of the FLIPSS, the formation mechanisms of each type of FLIPSS are discussed. The formation of the ripples is well explained by the propagating of the surface plasma wave (SPW) on the air/Ti interface. The evolutions of the ripple distribution are well understood according to this model as well. It is concluded that the interaction of the scattered wave of the laser light with the surface wave is concluded to give rise to the microgroove structure. According to our observation, the shape of the concentric rings does not change with the variation of the laser fluence and pulse number. The structure could be originated from the optical interference between the transmitted and reflected laser beams by the two surfaces of the biconvex lens. This investigation could not only make a further understanding of the formations of FLIPSS but also provide the possibility to control the surface morphologies in laser processing.

  15. The correlated evolution of three-dimensional reproductive structures between male and female damselflies.

    Science.gov (United States)

    McPeek, Mark A; Shen, Li; Farid, Hany

    2009-01-01

    For many taxa, species are defined by the morphologies of reproductive structures. In many odonates, these structures are the cerci of males (used to hold females during mating) and the thoracic plates of females where the male cerci contact the females' bodies. A previous study showed that the shapes of cerci of Enallagma males (Zygoptera: Coenagrionidae) are best explained by an evolutionary model of punctuated change at the time of speciation, with a homogeneous rate of change across the entire phylogeny of the genus. In the present study, we examine the evolution of shape change in the corresponding female plates. We found that, like male cerci, the shapes of Enallagma female thoracic plates could best be explained by an evolutionary model of punctuated change at the time of speciation, with a homogeneous rate of change across the clade. Moreover, the evolutionary contrasts quantifying the rates of change in male cerci and female thoracic plates were positively related across the history of the clade, demonstrating that these male and female structures evolve in a correlated fashion. This pattern of evolution suggests that these structures are primary signals of species identity during mating.

  16. The tempo and mode of three-dimensional morphological evolution in male reproductive structures.

    Science.gov (United States)

    McPeek, Mark A; Shen, Li; Torrey, John Z; Farid, Hany

    2008-05-01

    Various evolutionary forces may shape the evolution of traits that influence the mating decisions of males and females. Phenotypic traits that males and females use to judge the species identify of potential mates should evolve in a punctuated fashion, changing significantly at the time of speciation but changing little between speciation events. In contrast, traits experiencing sexual selection or sexually antagonistic interactions are generally expected to change continuously over time because of the directional selection pressures imposed on one sex by the actions of the other. To test these hypotheses, we used spherical harmonic representations of the shapes of male mating structures in reconstructions of the evolutionary tempo of these structures across the history of the Enallagma damselfly clade. Our analyses show that the evolution of these structures is completely consistent with a punctuated model of evolutionary change and a constant evolutionary rate throughout the clade's history. In addition, no interpopulation variation in shape was detected across the range of one species. These results indicate that male mating structures in this genus are used primarily for identifying the species of potential mates and experience little or no selection from intraspecific sexual selection or sexual antagonism. The implications of these results for speciation are discussed.

  17. 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.

  18. 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.

  19. 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...

  20. 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.

  1. Analysis model of structure-HDS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the model established for Structure-HDS(hydraulic damper system) analysis on the basis of the theoretical analysis model of non-compressed fluid in the round pipe will an uniform velocity used as the basic variable, and pressure losses resulting from cross section changes of fluid route taken into consideration. Which provides necessary basis for researches on earthquake responses of a structure with a spacious first story, equipped with HDS at first floor.

  2. Analysis of Haptics Evolution from Web Search Engines’ Data

    Directory of Open Access Journals (Sweden)

    Agnès Guerraz

    2009-08-01

    Full Text Available This article proposes using search engine results data such as the number of results containing relevant terms, to measure the evolution of Haptics, the field devoted to the science and technology of the sense of touch. Haptics is a complex discipline which is at the intersection of the knowledge of several specialized fields like robotics, computer science, psychology, and mathematics. It can also appear as a new and emergent discipline due to the fact that many promising haptic interfaces, which allow innovative multimodal applications in many fields, have become mature only recently. The study presented in this article uses data collected at different periods of time (in December 1999, January 2004, January 2005, November 2006 and April 2007 onWeb search engines from requests on three different terminologies: haptique, haptik and haptics, taken respectively from French, German, and English languages. The evolution of Haptics is seemingly reflected by to the online frequency of these specific terms over time. This evolution has been measured by considering the Internet community through search engines such as Google or Yahoo!

  3. Genetic analysis of wheat domestication and evolution under domestication.

    Science.gov (United States)

    Peleg, Zvi; Fahima, Tzion; Korol, Abraham B; Abbo, Shahal; Saranga, Yehoshua

    2011-10-01

    Wheat is undoubtedly one of the world's major food sources since the dawn of Near Eastern agriculture and up to the present day. Morphological, physiological, and genetic modifications involved in domestication and subsequent evolution under domestication were investigated in a tetraploid recombinant inbred line population, derived from a cross between durum wheat and its immediate progenitor wild emmer wheat. Experimental data were used to test previous assumptions regarding a protracted domestication process. The brittle rachis (Br) spike, thought to be a primary characteristic of domestication, was mapped to chromosome 2A as a single gene, suggesting, in light of previously reported Br loci (homoeologous group 3), a complex genetic model involved in spike brittleness. Twenty-seven quantitative trait loci (QTLs) conferring threshability and yield components (kernel size and number of kernels per spike) were mapped. The large number of QTLs detected in this and other studies suggests that following domestication, wheat evolutionary processes involved many genomic changes. The Br gene did not show either genetic (co-localization with QTLs) or phenotypic association with threshability or yield components, suggesting independence of the respective loci. It is argued here that changes in spike threshability and agronomic traits (e.g. yield and its components) are the outcome of plant evolution under domestication, rather than the result of a protracted domestication process. Revealing the genomic basis of wheat domestication and evolution under domestication, and clarifying their inter-relationships, will improve our understanding of wheat biology and contribute to further crop improvement.

  4. A theoretical model for the evolution of two-dimensional large-scale coherent structures in a mixing layer

    Institute of Scientific and Technical Information of China (English)

    周恒; 马良

    1995-01-01

    By a proper combination of the modified weakly nonlinear theory of hydrodynamic stability and the energy method, the spatial evolution of the large-scale coherent structures in a mixing layer has been calculated. The results are satisfactory.

  5. Structure and evolution of the Afanasy Nikitin seamount, buried hills and 85 degrees E Ridge in the northeastern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.

    Geophysical data of the Afanasy Nikitin seamount (ANS), partly buried hills and 85 degrees E Ridge in the northeastern Indian Ocean were studied together with published seismic refraction results to understand genesis and evolution of the structures...

  6. 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

  7. SPATIAL STRUCTURE EVOLUTION OF SYSTEM OF RECREATION BUSINESS DISTRICT--A Case of Suzhou City

    Institute of Scientific and Technical Information of China (English)

    LI Li-mei; TAO Wei

    2003-01-01

    The growing attention on urban tourism was very widespread. There are two angles to study urban tourism: supply-side and demand-side. And the supply-side of the tourism remains very important. The RBD (Recreation Business District) is a useful framework to understand the components of urban tourism and how they fit together. The paper begins with a review on the RBD and the spatial structure of tourism in urban areas and then attempts to develop a more general understanding of the spatial structure evolution of RBDs in a tourist-historic citySuzhou. The spatial structures and functions of the RBDs in Suzhou are examined, based on field observations, interviews with city officials and industry leaders, and a review of available documents. The urban tourism of Suzhou has developed in a range of contexts, that various types of RBDs have emerged as a result of different urban development strategies. The spatial structure has evolved from the past "Single-cored Structure" to "Double-cored Structure"at present, and then to "Chain Structure" in the future. The spatial form and evolution of RBD in Suzhou are closely relative with its urban spatial expansion. Urban area dispersal is the prerequisite of the emergence of the RBD. Planning and constructing the RBD becomes a new impetus to urban growth or renewal. Finally, a number of strategies for planning and developing the RBD in Suzhou are suggested. The different RBDs should adopt different strategies.Intensification can be the possible strategy for the RBDs in the ancient city. Accreting with the urban theme park or engrafting on the Jinji Lake is suggested respectively for the RBD in the Suzhou New District and the Suzhou Industrial Park.

  8. Structural Evolution of Core-Shell Gold Nanoclusters: Aun(-) (n = 42-50).

    Science.gov (United States)

    Pande, Seema; Huang, Wei; Shao, Nan; Wang, Lei-Ming; Khetrapal, Navneet; Mei, Wai-Ning; Jian, Tian; Wang, Lai-Sheng; Zeng, Xiao Cheng

    2016-11-22

    Gold nanoclusters have attracted great attention in the past decade due to their remarkable size-dependent electronic, optical, and catalytic properties. However, the structures of large gold clusters are still not well-known because of the challenges in global structural searches. Here we report a joint photoelectron spectroscopy (PES) and theoretical study of the structural evolution of negatively charged core-shell gold nanoclusters (Aun(-)) for n = 42-50. Photoelectron spectra of size-selected Aun(-) clusters are well resolved with distinct spectral features, suggesting a dominating structural type. The combined PES data and density functional calculations allow us to systematically identify the global minimum or candidates of the global minima of these relatively large gold nanoclusters, which are found to possess low-symmetry structures with gradually increasing core sizes. Remarkably, the four-atom tetrahedral core, observed first in Au33(-), continues to be highly robust and is even present in clusters as large as Au42(-). Starting from Au43(-), a five-atom trigonal bipyramidal core appears and persists until Au47(-). Au48(-) possesses a six-atom core, while Au49(-) and Au50(-) feature seven- and eight-atom cores, respectively. Notably, both Au46(-) and Au47(-) contain a pyramidal Au20 motif, which is stacked with another truncated pyramid by sharing a common 10-atom triangular face. The present study sheds light on our understanding of the structural evolution of the medium-sized gold nanoclusters, the shells and core as well as how the core-shell structures may start to embrace the golden pyramid (bulk-like) fragment.

  9. The Mass, Color, and Structural Evolution of Today’s Massive Galaxies Since z ∼ 5

    Science.gov (United States)

    Hill, Allison R.; Muzzin, Adam; Franx, Marijn; Clauwens, Bart; Schreiber, Corentin; Marchesini, Danilo; Stefanon, Mauro; Labbe, Ivo; Brammer, Gabriel; Caputi, Karina; Fynbo, Johan; Milvang-Jensen, Bo; Skelton, Rosalind E.; van Dokkum, Pieter; Whitaker, Katherine E.

    2017-03-01

    In this paper, we use stacking analysis to trace the mass growth, color evolution, and structural evolution of present-day massive galaxies ({log}({M}* /{M}ȯ )=11.5) out to z = 5. We utilize the exceptional depth and area of the latest UltraVISTA data release, combined with the depth and unparalleled seeing of CANDELS to gather a large, mass-selected sample of galaxies in the NIR (rest-frame optical to UV). Progenitors of present-day massive galaxies are identified via an evolving cumulative number density selection, which accounts for the effects of merging to correct for the systematic biases introduced using a fixed cumulative number density selection, and find progenitors grow in stellar mass by ≈ 1.5 {dex} since z = 5. Using stacking, we analyze the structural parameters of the progenitors and find that most of the stellar mass content in the central regions was in place by z∼ 2, and while galaxies continue to assemble mass at all radii, the outskirts experience the largest fractional increase in stellar mass. However, we find evidence of significant stellar mass build-up at r 4 probing an era of significant mass assembly in the interiors of present-day massive galaxies. We also compare mass assembly from progenitors in this study to the EAGLE simulation and find qualitatively similar assembly with z at r< 3 {kpc}. We identify z∼ 1.5 as a distinct epoch in the evolution of massive galaxies where progenitors transitioned from growing in mass and size primarily through in situ star formation in disks to a period of efficient growth in r e consistent with the minor merger scenario.

  10. Generalized Structured Component Analysis with Latent Interactions

    Science.gov (United States)

    Hwang, Heungsun; Ho, Moon-Ho Ringo; Lee, Jonathan

    2010-01-01

    Generalized structured component analysis (GSCA) is a component-based approach to structural equation modeling. In practice, researchers may often be interested in examining the interaction effects of latent variables. However, GSCA has been geared only for the specification and testing of the main effects of variables. Thus, an extension of GSCA…

  11. Using rhetorical structure in sentiment analysis

    NARCIS (Netherlands)

    Hogenboom, Alexander; Frasincar, Flavius; Jong, de Franciska; Kaymak, Uzay

    2015-01-01

    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 s

  12. Group theory analysis of braided geometry structures

    Institute of Scientific and Technical Information of China (English)

    FENG Wei; MA Wensuo

    2005-01-01

    The braided geometry structures are analyzed with point groups and space groups for which the continuous yarn of the braided preforms is segmented and expressed in some special symbols. All structures of braided material are described and classified with group theory, and new braiding methods are found. The group theory analysis lays the theoretical foundation for optimizing material performance.

  13. Magnetic Structure of Continental Crust:Implications for Crustal Structure and Evolution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Magnetic structure of the continental crust is one of the important geophysical aspects of continental lithosphere. This paper reviews the achievements in the research into the magnetic structure and its significance for crustal tectonics, composition, metamorphic facies, crust-mantle interaction and magnetization of deep crust. Further studies are suggested according to the basic principles of rock and mineral magnetism in terms of petrology, geochemistry and structural geol ogy. Emphasis is placed on new geological ideas and synthetic studies of the relationship between deep geological processes and interpretation of gravity, magnetic, electrical and seismic data. The relationships between magnetic, density, electricity, velocity, geothermal structures and deep geodynamic processes are taken as a system for the research into the deep geology.

  14. The organization of Jupiter's upper tropospheric temperature structure and its evolution, 1996-1997

    Science.gov (United States)

    Fisher, Brendan M.; Orton, Glenn S.; Liu, Junjun; Schneider, Tapio; Ressler, Michael E.; Hoffman, William F.

    2016-12-01

    High signal-to-noise images of Jupiter were made at wavelengths between 13.2 and 22.8 μm in five separate observing runs between 1996 June and 1997 November at the NASA Infrared Telescope Facility. Maps of Jupiter's upper-tropospheric temperatures at pressures of 100 and 400 mbar were made from these images. We use the relatively frequent, well sampled data sets to examine in detail the short-term evolution of the temperature structure. Our 2-6 month sampling periods demonstrate that the longitudinal temperature structures evolve significantly in these short periods and exhibit wave features. Using a three-dimensional general circulation model simulation of Jupiter's upper atmosphere, we show that the thermal structures are consistent with convectively generated Rossby waves that propagate upward from the lower to the upper atmosphere.

  15. Highly efficient light-trapping structure design inspired by natural evolution.

    Science.gov (United States)

    Wang, Chen; Yu, Shuangcheng; Chen, Wei; Sun, Cheng

    2013-01-01

    Recent advances in nanophotonic light trapping open up the new gateway to enhance the absorption of solar energy beyond the so called Yablonovitch Limit. It addresses the urgent needs in developing low cost thin-film solar photovoltaic technologies. However, current design strategy mainly relies on the parametric approach that is subject to the predefined topological design concepts based on physical intuition. Incapable of dealing with the topological variation severely constrains the design of optimal light trapping structure. Inspired by natural evolution process, here we report a design framework driven by topology optimization based on genetic algorithms to achieve a highly efficient light trapping structure. It has been demonstrated that the optimal light trapping structures obtained in this study exhibit more than 3-fold increase over the Yablonovitch Limit with the broadband absorption efficiency of 48.1%, beyond the reach of intuitive designs.

  16. Structural evolution and strength change of a metallic glass at different temperatures

    Science.gov (United States)

    Tong, X.; Wang, G.; Stachurski, Z. H.; Bednarčík, J.; Mattern, N.; Zhai, Q. J.; Eckert, J.

    2016-08-01

    The structural evolution of a Zr64.13Cu15.75Ni10.12Al10 metallic glass is investigated in-situ by high-energy synchrotron X-ray radiation upon heating up to crystallization. The structural rearrangements on the atomic scale during the heating process are analysed as a function of temperature, focusing on shift of the peaks of the structure factor in reciprocal space and the pair distribution function and radial distribution function in real space which are correlated with atomic rearrangements and progressing nanocrystallization. Thermal expansion and contraction of the coordination shells is measured and correlated with the bulk coefficient of thermal expansion. The characteristics of the microstructure and the yield strength of the metallic glass at high temperature are discussed aiming to elucidate the correlation between the atomic arrangement and the mechanical properties.

  17. The importance of structural softening for the evolution and architecture of passive margins

    Science.gov (United States)

    Duretz, T.; Petri, B.; Mohn, G.; Schmalholz, S. M.; Schenker, F. L.; Müntener, O.

    2016-12-01

    Lithospheric extension can generate passive margins that bound oceans worldwide. Detailed geological and geophysical studies in present and fossil passive margins have highlighted the complexity of their architecture and their multi-stage deformation history. Previous modeling studies have shown the significant impact of coarse mechanical layering of the lithosphere (2 to 4 layer crust and mantle) on passive margin formation. We built upon these studies and design high-resolution (~100–300 m) thermo-mechanical numerical models that incorporate finer mechanical layering (kilometer scale) mimicking tectonically inherited heterogeneities. During lithospheric extension a variety of extensional structures arises naturally due to (1) structural softening caused by necking of mechanically strong layers and (2) the establishment of a network of weak layers across the deforming multi-layered lithosphere. We argue that structural softening in a multi-layered lithosphere is the main cause for the observed multi-stage evolution and architecture of magma-poor passive margins.

  18. ON THE EVOLUTION OF LARGE SCALE STRUCTURES IN THREE-DIMENSIONAL MIXING LAYERS

    Institute of Scientific and Technical Information of China (English)

    罗纪生; H.E, Fiedler

    2001-01-01

    In this paper, several mathematical models for the large scale structures in some special kinds of mixing layers, which might be practically useful for enhancing the mixing, are proposed. First, the linear growth rate of the large scale structures in the mixing layers was calculated. Then, using the much improved weakly non-linear theory, combined with the energy method, the non-linear evolution of large scale structures in two special mixing layer configurations is calculated. One of the mixing layers has equal magnitudes of the upstream velocity vectors, while the angles between the velocity vectors and the trailing edge were π/2 - and π/2 + ,respectively. The other mixing layer was generated by a splitter-plate with a 45-degree-sweep trailing edge.

  19. Evolution of Prolate Molecular Clouds at HII Boundaries: I. Formation of fragment-core structures

    CERN Document Server

    Kinnear, Timothy M; White, Glenn J; Goodwin, Simon

    2014-01-01

    The evolution of a prolate cloud at an Hii boundary is investigated using Smoothed Particle Hydrodynamics (SPH). The prolate molecular clouds in our investigation are set with their semi-major axis perpendicular to the radiative direction of a plane parallel ionising Extreme Ultraviolet (EUV) flux. Simulations on three high mass prolate clouds reveal that EUV radiation can trigger distinctive high density core formation embedded in a final linear structure. This contrasts with results of the previous work in which only an isotropic Far Ultraviolet (FUV) interstellar background flux was applied. A systematic investigation on a group of prolate clouds of equal mass but different initial densities and geometric shapes finds that the distribution of the cores over the final linear structure changes with the initial conditions of the prolate cloud and the strength of the EUV radiation flux. These highly condensed cores may either scatter over the full length of the final linear structure or form two groups of high...

  20. Bayesian analysis of cosmic structures

    CERN Document Server

    Kitaura, Francisco-Shu

    2011-01-01

    We revise the Bayesian inference steps required to analyse the cosmological large-scale structure. Here we make special emphasis in the complications which arise due to the non-Gaussian character of the galaxy and matter distribution. In particular we investigate the advantages and limitations of the Poisson-lognormal model and discuss how to extend this work. With the lognormal prior using the Hamiltonian sampling technique and on scales of about 4 h^{-1} Mpc we find that the over-dense regions are excellent reconstructed, however, under-dense regions (void statistics) are quantitatively poorly recovered. Contrary to the maximum a posteriori (MAP) solution which was shown to over-estimate the density in the under-dense regions we obtain lower densities than in N-body simulations. This is due to the fact that the MAP solution is conservative whereas the full posterior yields samples which are consistent with the prior statistics. The lognormal prior is not able to capture the full non-linear regime at scales ...

  1. Polarity Analysis of Texts using Discourse Structure

    NARCIS (Netherlands)

    Heerschop, Bas; Goosen, Frank; Hogenboom, Alexander; Frasincar, Flavius; Kaymak, Uzay; Jong, de Franciska

    2011-01-01

    Sentiment analysis has applications in many areas and the exploration of its potential has only just begun. We propose Pathos, a framework which performs document sentiment analysis (partly) based on a document’s discourse structure. We hypothesize that by splitting a text into important and less im

  2. 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.

  3. Structural Analysis Of Offshore Structures Exposed To Blast Loads

    DEFF Research Database (Denmark)

    Hansen, Hans Jakup; Thygesen, Ulf; Kristensen, Anders;

    2002-01-01

    Numerical methods for simulations of blast loads and resulting structural response are investigated and compared to results obtained from tests. The CFD code EXSIM is used for the simulation of the blast load. This code provides a load profile wich is entered in the FEM analysis model....

  4. Structural evolution of fault zones in sandstone by multiple deformation mechanisms: Moab fault, southeast Utah

    Science.gov (United States)

    Davatzes, N.C.; Eichhubl, P.; Aydin, A.

    2005-01-01

    Faults in sandstone are frequently composed of two classes of structures: (1) deformation bands and (2) joints and sheared joints. Whereas the former structures are associated with cataclastic deformation, the latter ones represent brittle fracturing, fragmentation, and brecciation. We investigated the distribution of these structures, their formation, and the underlying mechanical controls for their occurrence along the Moab normal fault in southeastern Utah through the use of structural mapping and numerical elastic boundary element modeling. We found that deformation bands occur everywhere along the fault, but with increased density in contractional relays. Joints and sheared joints only occur at intersections and extensional relays. In all locations , joints consistently overprint deformation bands. Localization of joints and sheared joints in extensional relays suggests that their distribution is controlled by local variations in stress state that are due to mechanical interaction between the fault segments. This interpretation is consistent with elastic boundary element models that predict a local reduction in mean stress and least compressive principal stress at intersections and extensional relays. The transition from deformation band to joint formation along these sections of the fault system likely resulted from the combined effects of changes in remote tectonic loading, burial depth, fluid pressure, and rock properties. In the case of the Moab fault, we conclude that the structural heterogeneity in the fault zone is systematically related to the geometric evolution of the fault, the local state of stress associated with fault slip , and the remote loading history. Because the type and distribution of structures affect fault permeability and strength, our results predict systematic variations in these parameters with fault evolution. ?? 2004 Geological Society of America.

  5. A protein structure data and analysis system.

    Science.gov (United States)

    Tian, Hao; Sunderraman, Rajshekhar; Weber, Irene; Wang, Haibin; Yang, Hong

    2005-01-01

    In this paper, we present the design and implementation of a protein structure data and analysis system that is only used in the lab for analyzing the proprietary data. It is capable of storing public protein data, such as the data in Protein Data Bank (PDB) [1], and life scientists' proprietary data. This toolkit is targeted at life scientists who want to maintain proprietary protein structure data (may be incomplete), to search and query publicly known protein structures and to compare their structure data with others. The comparison functions can be used to find structure differences between two proteins at atom level, especially in mutant versions of proteins. The system can also be used as a tool of choosing better protein structure template in new protein's tertiary structure prediction. The system is developed in Java and the protein data is stored in a relational database (Oracle 9i).

  6. Seismic analysis of nuclear power plant structures

    Science.gov (United States)

    Go, J. C.

    1973-01-01

    Primary structures for nuclear power plants are designed to resist expected earthquakes of the site. Two intensities are referred to as Operating Basis Earthquake and Design Basis Earthquake. These structures are required to accommodate these seismic loadings without loss of their functional integrity. Thus, no plastic yield is allowed. The application of NASTRAN in analyzing some of these seismic induced structural dynamic problems is described. NASTRAN, with some modifications, can be used to analyze most structures that are subjected to seismic loads. A brief review of the formulation of seismic-induced structural dynamics is also presented. Two typical structural problems were selected to illustrate the application of the various methods of seismic structural analysis by the NASTRAN system.

  7. The role of disc self-gravity in circumbinary planet systems - I. Disc structure and evolution

    Science.gov (United States)

    Mutter, Matthew M.; Pierens, Arnaud; Nelson, Richard P.

    2017-03-01

    We present the results of two-dimensional hydrodynamic simulations of self-gravitating circumbinary discs around binaries whose parameters match those of the circumbinary planet-hosting systems Kepler-16, Kepler-34 and Kepler-35. Previous work has shown that non-self-gravitating discs in these systems form an eccentric precessing inner cavity due to tidal truncation by the binary, and planets which form at large radii migrate until stalling at this cavity. Whilst this scenario appears to provide a natural explanation for the observed orbital locations of the circumbinary planets, previous simulations have failed to match the observed planet orbital parameters. The aim of this work is to examine the role of self-gravity in modifying circumbinary disc structure as a function of disc mass, prior to considering the evolution of embedded circumbinary planets. In agreement with previous work, we find that for disc masses between one and five times the minimum mass solar nebula (MMSN), disc self-gravity affects modest changes in the structure and evolution of circumbinary discs. Increasing the disc mass to 10 or 20 MMSN leads to two dramatic changes in disc structure. First, the scale of the inner cavity shrinks substantially, bringing its outer edge closer to the binary. Secondly, in addition to the eccentric inner cavity, additional precessing eccentric ring-like features develop in the outer regions of the discs. If planet formation starts early in the disc lifetime, these changes will have a significant impact on the formation and evolution of planets and precursor material.

  8. Structural-Thermal-Optical-Performance (STOP) Analysis

    Science.gov (United States)

    Bolognese, Jeffrey; Irish, Sandra

    2015-01-01

    The presentation will be given at the 26th Annual Thermal Fluids Analysis Workshop (TFAWS 2015) hosted by the Goddard Spaceflight Center (GSFC) Thermal Engineering Branch (Code 545). A STOP analysis is a multidiscipline analysis, consisting of Structural, Thermal and Optical Performance Analyses, that is performed for all space flight instruments and satellites. This course will explain the different parts of performing this analysis. The student will learn how to effectively interact with each discipline in order to accurately obtain the system analysis results.

  9. 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.

  10. 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.

  11. Evolution of the upper-level thermal structure in tropical cyclones

    Science.gov (United States)

    Rivoire, Louis; Birner, Thomas; Knaff, John A.

    2016-10-01

    Tropical cyclones (TCs) are associated with tropopause-level cooling above tropospheric warming. We collect temperature retrievals from 2007 to 2014 near worldwide hurricane-strength TCs using three remote sensing platforms: the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), the Advanced Microwave Sounding Unit-A (AMSU-A), and geostationary infrared (IR) imagery. These retrievals are composited about the lifetime maximum intensity (LMI) to examine the evolution of the fine-scale temperature structure within TCs. The convective structure evolves highly asymmetrically about LMI, while intensity evolution shows a much weaker degree of asymmetry. Relative to the far-field structure, tropopause-level cooling occurs before a tropospheric warm core is established. We speculate that the associated convective destabilization exerts a positive feedback on TC development by increasing the depth of existing convection. Tropopause-level cold anomalies move away from the storm after LMI, potentially increasing the near-surface horizontal pressure gradient toward the storm center and increasing the maximum winds.

  12. The molecular clock of neutral evolution can be accelerated or slowed by asymmetric spatial structure.

    Science.gov (United States)

    Allen, Benjamin; Sample, Christine; Dementieva, Yulia; Medeiros, Ruben C; Paoletti, Christopher; Nowak, Martin A

    2015-02-01

    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.

  13. The Influence of Outer Solar System Architecture on the Structure and Evolution of the Oort Cloud

    CERN Document Server

    Lewis, Alexia R; Kaib, Nathan A

    2013-01-01

    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 i...

  14. 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.

  15. 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

  16. Experimental analysis of microscale rain cells and their dynamic evolution

    Science.gov (United States)

    Enjamio, C.; Vilar, E.; RedañO, A.; FontáN, F. P.; Ndzi, D.

    2005-06-01

    This paper presents a detailed space-time analysis of rainfall rate using two dense networks of rain gauges covering two microscale areas of some 100 km2 each and located in two distinct climatic areas in the United Kingdom and Spain. The study has been carried out with the main objective of addressing dynamic fade mitigation techniques and scatter interference problems in terrestrial and satellite communication systems. The two databases, using a total of 49 and 23 rain gauges, respectively, are described, and the continuous interpolated field used for the subsequent analyses is explained in detail. The suitability of the networks in terms of density, correlation distance, and fractal dimension are briefly addressed. A to-scale comparison grid of the networks is also given. It has been found that when the maximum intensity reached during a rain event surpasses a certain threshold, different for each of the two areas, rainfall rates exhibit a spatial structure in the form of closed contours of thresholds referred to as cells. In statistical terms, the most probable diameter found is about 3.5 km, and distributions are presented. They are similar for the two sites but not so for the maxima reached inside the cells. Using cross-correlation techniques, displacement and velocities are analyzed in detail. Cells "zigzag" around a dominant trend because of the global cloud movements (driven by winds at heights of about 700 hPa). Local topography strongly affects local behavior. Analytical approximations to the experimental statistical distributions and selected histograms of the results are presented.

  17. Analysis of microstructural evolution driven by production bias

    DEFF Research Database (Denmark)

    Woo, C.H.; Semenov, A.A.; Singh, B.N.

    1993-01-01

    The concept of production bias was first considered in the preceding workshop in this series at Silkeborg in 1989. Since then, much work has been done to investigate the validity of the concept, and its usefulness in complementing the current theory of microstructure evolution based solely...... on the sink bias (e.g., dislocation bias) as a driving force. Comparison of the theory with experimental results clearly supports the concept. The present paper reviews and summarizes these investigations, and arrives at the following conclusions: a) the concept of production bias is consistent...

  18. Evolution of the Interplanetary Magnetic Field sector structure during the last 15 solar cycles

    Science.gov (United States)

    Vokhmyanin, Mikhail

    We have inferred for the first time Interplanetary Magnetic Field (IMF) polarities from ground-based geomagnetic observations back to 1844. Reconstructions are reliable enough to study sector structure of the IMF in the past. The inferred daily polarities demonstrate solar-cycle changes during the nineteenth and twentieth centuries. We have analyzed statistics of the sector boundaries and found recurrences that reflect evolution of the solar wind sources. Additionally, seasonal variations of the ratio of positive and negative sectors provide evidence of solar magnetic field reversals during the last 15 solar cycles.

  19. 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.

  20. 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.

  1. Investigation of thermal evolution of nanodomain structures in nonlinear barium sodium niobate crystals

    Institute of Scientific and Technical Information of China (English)

    S.V.Ivanova

    2008-01-01

    By the 90°elastic light scattering investigation and far field observation in the range of 20-800℃,the relation between behavior of light scattering anomalies and evolution of nanodomain structures in lattice of barium sodium niobate(Ba2NaNb5O15,BSN)crystal was clarified.The correlation between anomalies on the temperature curves of the elastic light scattering intensity and temperature transformations of nanodomains was studied by X-ray and electron microscope methods.Phase transition near 500℃ and movement in field of scattering light could be explained by appearance of a new incommensurate phase.

  2. Evolution of the fine-structure constant in runaway dilaton models

    CERN Document Server

    Martins, C J A P; Martinelli, M; Calabrese, E; Pandolfi, S

    2015-01-01

    We study the detailed evolution of the fine-structure constant $\\alpha$ in the string-inspired runaway dilaton class of models of Damour, Piazza and Veneziano. We provide constraints on this scenario using the most recent $\\alpha$ measurements and discuss ways to distinguish it from alternative models for varying $\\alpha$. For model parameters which saturate bounds from current observations, the redshift drift signal can differ considerably from that of the canonical $\\Lambda$CDM paradigm at high redshifts. Measurements of this signal by the forthcoming European Extremely Large Telescope (E-ELT), together with more sensitive $\\alpha$ measurements, will thus dramatically constrain these scenarios.

  3. Physical Properties and Evolution of Gravitationally Bound Halo Structures in Cosmological Dark Matter Simulations

    Science.gov (United States)

    Lin, David; Rocha, Miguel E.; Primack, Joel R.

    2015-01-01

    Dark matter halos existing around visible galaxies are important for studies of galaxy formation and evolution. Since dark matter does not interact with light and cannot be observed directly, studies of dark matter halos are advanced by computer simulations. Normally, halos are defined by their virialized regions; however, regions that are non-virialized can still be gravitationally bound, like the collision-bound Milky Way and Andromeda galaxies. Our project is the first comprehensive characterization of gravitationally bound halo structures, their properties, and their evolution. This study found the bound regions surrounding every dark matter halo from a 100 Mpc cube of the Bolshoi Simulation at redshifts 0, 1, and 2. We optimized computation by removing subhalos, implementing a search radius, and parallelizing code across 160 supercomputer cores. Then, we created a mass function, circular velocity function, and correlation function to describe these regions. The evolution of these properties was consistent with predictions from a ΛCDM universe model. We characterized the sizes and shapes of these bound regions across different mass intervals and redshifts. Most bound regions are elongated, although they become more spheroidal with time. The results enable astronomers to predict how dark matter halos behave in non-virialized regions of space and deepen our understanding of galaxy formation.

  4. The structural and size evolution of star-forming galaxies over the last 11 Gyrs

    CERN Document Server

    Paulino-Afonso, Ana; Buitrago, Fernando; Afonso, Jose

    2016-01-01

    We present new results on the evolution of rest-frame blue/UV sizes and Sersic indices of H$\\alpha$-selected star-forming galaxies over the last 11 Gyrs. We investigate how the perceived evolution can be affected by a range of biases and systematics such as cosmological dimming and resolution effects. We use GALFIT and an artificial redshifting technique, which includes the luminosity evolution of H$\\alpha$-selected galaxies, to quantify the change on the measured structural parameters with redshift. We find typical sizes of 2 to 3 kpc and Sersic indices of n~1.2, close to pure exponential disks all the way from z=2.23 to z=0.4. At z=0 we find typical sizes of 4-5 kpc. Our results show that, when using GALFIT, cosmological dimming has a negligible impact on the derived effective radius for galaxies with <10 kpc, but we find a ~20% bias on the estimate of the median Sersic indices, rendering galaxies more disk-like. Star-forming galaxies have grown on average by a factor of 2-3 in the last 11 Gyrs with $r_e...

  5. The structural and size evolution of star-forming galaxies over the last 11 Gyr

    Science.gov (United States)

    Paulino-Afonso, Ana; Sobral, David; Buitrago, Fernando; Afonso, José

    2017-03-01

    We present new results on the evolution of rest-frame blue/UV sizes and Sérsic indices of Hα-selected star-forming galaxies over the last 11 Gyr. We investigate how the perceived evolution can be affected by a range of biases and systematics such as cosmological dimming and resolution effects. We use GALFIT and an artificial redshifting technique, which includes the luminosity evolution of Hα-selected galaxies, to quantify the change on the measured structural parameters with redshift. We find typical sizes of 2-3 kpc and Sérsic indices of n ∼ 1.2, close to pure exponential discs all the way from z = 2.23 to z = 0.4. At z = 0, we find typical sizes of 4-5 kpc. Our results show that, when using GALFIT, cosmological dimming has a negligible impact on the derived effective radius for galaxies with frame blue/UV, we are likely witnessing the growth of discs where star formation is ongoing in galaxies while their profiles remain close to exponential discs, n ≲ 1.5, across the same period.

  6. 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.

  7. 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.

  8. Advanced analysis for structural steel building design

    Institute of Scientific and Technical Information of China (English)

    Wai Fah CHEN

    2008-01-01

    The 2005 AISC LRFD Specifications for Structural Steel Buildings are making it possible for designers to recognize explicitly the structural resistance provided within the elastic and inelastic ranges of beha-vior and up to the maximum load limit state. There is an increasing awareness of the need for practical second-order analysis approaches for a direct determination of overall structural system response. This paper attempts to present a simple, concise and reasonably comprehens-ive introduction to some of the theoretical and practical approaches which have been used in the traditional and modern processes of design of steel building structures.

  9. Telomerase and telomere-associated proteins: structural insights into mechanism and evolution.

    Science.gov (United States)

    Lewis, Karen A; Wuttke, Deborah S

    2012-01-11

    Recent advances in our structural understanding of telomerase and telomere-associated proteins have contributed significantly to elucidating the molecular mechanisms of telomere maintenance. The structures of telomerase TERT domains have provided valuable insights into how experimentally identified conserved motifs contribute to the telomerase reverse transcriptase reaction. Additionally, structures of telomere-associated proteins in a variety of organisms have revealed that, across evolution, telomere-maintenance mechanisms employ common structural elements. For example, the single-stranded 3' overhang of telomeric DNA is specifically and tightly bound by an OB-fold in nearly all species, including ciliates (TEBP and Pot1a), fission yeast (SpPot1), budding yeast (Cdc13), and humans (hPOT1). Structures of the yeast Cdc13, Stn1, and Ten1 proteins demonstrated that telomere maintenance is regulated by a complex that bears significant similarity to the RPA heterotrimer. Similarly, proteins that specifically bind double-stranded telomeric DNA in divergent species use homeodomains to execute their functions (human TRF1 and TRF2 and budding yeast ScRap1). Likewise, the conserved protein Rap1, which is found in budding yeast, fission yeast, and humans, contains a structural motif that is known to be critical for protein-protein interaction. In addition to revealing the common underlying themes of telomere maintenance, structures have also elucidated the specific mechanisms by which many of these proteins function, including identifying a telomere-specific domain in Stn1 and how the human TRF proteins avoid heterodimerization. In this review, we summarize the high-resolution structures of telomerase and telomere-associated proteins and discuss the emergent common structural themes among these proteins. We also address how these high-resolution structures complement biochemical and cellular studies to enhance our understanding of telomere maintenance and function.

  10. 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

  11. 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.

  12. Genetic evolution of structural region of hepatitis C virus in primary infection

    Institute of Scientific and Technical Information of China (English)

    Song Chen; Yu-Ming Wang

    2002-01-01

    AIM: To investigate the dynamics of hepatitis C virus(HCV) variability through putative envelope genesduring primary infection and the mechanism of viralgenetic evolution in infected hosts.METHODS: Serial serum samples prospectively collectedfor 12 to 34 months from a cohort of acutely HCV-infected individuals were obtained, and a 1-kb fragmentspanning E1 and the 5' half of E2, including Thirty-threecloned cDNAs representing each specimen wereassessed by a method that combined a single-strandedconformational polymorphism (SSCP) and heteroduplexanalysis (HDA) method to determine the number ofclonotypes hypervariable region, was amplified byreverse transcriptase PCR and cloned.Nonsynonymousmutations per nonsynonymous site (dn), synonymousmutations per synonymous site (ds), dn/ds ratio andgenetic distances within each sample were evaluatedfor intrahost evolutionary analysis.RESULTS: Quasispecies complexity and sequencediversity were lower in early samples and a furtherincrease after seroconversion, although ds value in theenvelope genes was higher than dn value duringprimary infection. The trend, pronounced in most ofsamples, toward lower ds values in the E1 than in the5' portion of E2. Quasispecies complexity was higherand E2 dn/ds ratio was a trend toward higher value inlater samples during persistent viremia. We also foundindividual features of HCV genetic evolution in differentsubjects who were infected with different HCVgenotypes.CONCLUSION: Mutations of actively replicating virusarise stochastically with certain functional constaints.A complexity quasispecies exerted by a combination ofeither neutral evolution or selective forces shows cleardifferences in individuals, and associated with HCVpersistence.

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

    Science.gov (United States)

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

    2011-01-01

    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. We leverage methodological advancements (i.e.,…

  14. 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.

  15. Structure build-up and evolution in the drying of sessile blood droplets

    Science.gov (United States)

    Craster, Richard; Uppal, Aran; Matar, Omar

    2016-11-01

    Experimental observations have recorded blood undergoing a sol-gel transition during the evaporation process. Consequently, the rheology becomes non-uniform throughout the droplet and exhibits transitional complex phenomena that we must capture if we wish to accurately model the evaporative/cracking process. We propose a model where thixotropy is introduced to capture the evolving rheology as evaporation occurs. Thixotropy is often used to describe fluids which exhibit a decrease in viscosity due to flow and subsequent slow recovery of viscosity after the cessation of the flow. We introduce an additional parameter to describe the internal structure of the fluid at each point and consider a droplet in the limit of the lubrication approximation. We present a discussion of our results that demonstrates the dependence of structure build-up, which accompanies the spatio-temporal evolution of the drop, on system parameters. EPSRC UK Centre for Doctoral Training.

  16. Sex in smut fungi: Structure, function and evolution of mating-type complexes.

    Science.gov (United States)

    Bakkeren, Guus; Kämper, Jörg; Schirawski, Jan

    2008-08-01

    Smut fungi are basidiomycete plant pathogens that pose a threat to many important cereal crops. In order to be pathogenic on plants, smut fungal cells of compatible mating-type need to fuse. Fusion and pathogenicity are regulated by two loci, a and b, which harbor conserved genes. The functions of the encoded mating-type complexes have been well-studied in the model fungus Ustilago maydis and will be briefly reviewed here. Sequence comparison of the mating-type loci of different smut and related fungi has revealed that these loci differ substantially in structure. These structural differences point to an evolution from tetrapolar to bipolar mating behavior, which might have occurred several independent times during fungal speciation.

  17. Structure and evolution of solar supergranulation using SDO/HMI data

    CERN Document Server

    Roudier, Th; Rieutord, M; Malherbe, J M; Burston, R; Gizon, L

    2014-01-01

    Context: Studying the motions on the solar surface is fundamental for understanding how turbulent convection transports energy and how magnetic fields are distributed across the solar surface. Aims: From horizontal velocity measurements all over the visible disc of the Sun and using data from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI), we investigate the structure and evolution of solar supergranulation. Methods: Horizontal velocity fields were measured by following the proper motions of solar granules using a newly developed version of the coherent structure tracking (CST) code. With this tool, maps of horizontal divergence were computed. We then segmented and identified supergranular cells and followed their histories by using spatio-temporal labelling. With this dataset we derived the fundamental properties of supergranulation, including their motion. Results: We find values of the fundamental parameters of supergranulation similar to previous studies: a mean lifetime of 1.5 ...

  18. Structure, dynamics and evolution of disk galaxies in a hierarchical formation scenario

    CERN Document Server

    Firmani, C

    1999-01-01

    Using galaxy evolutionary models in a hierarchical formation scenario, we predict the structure, dynamics and evolution of disk galaxies in a LCDM universe. Our models include star formation and hydrodynamics of the ISM. We find that the Tully-Fisher relation (TFR) in the I and H bands is an imprint of the mass-velocity relation of the cosmological dark halos. The scatter of the TFR originates mainly from the scatter in the dark halo structure and, to a minor extension, from the dispersion of the primordial spin parameter lambda. Our models allow us to explain why low and high surface brightness galaxies have the same TFR. The disk gas fractions predicted agree with the observations. The disks formed within the growing halos have nearly exponential surface brightness and flat rotation curves. Towards high redshifts, the zero-point of the TFR in the H band increases while in the B-band it slightly decreases.

  19. Unified QCD evolution equations and the dominant behaviour of structure functions at low x

    CERN Document Server

    Peschanski, R; Peschanski, R; Wallon, S

    1994-01-01

    We consider a system of evolution equations for quark and gluon structure functions satisfying the leading-logarithmic behaviour due to both QCD collinear \\left(LLQ^2 \\right) and infrared (LL1/x) singularities. We show that these equations leave undetermined an arbitrary regular function of j in the Mellin-transformed weights. We consider the constraints resulting from energy-momentum conservation and from the decoupling of quark loops in the leading j -plane singularity. These constraints can be fulfilled without influencing the leading-log terms. As a particular consequence of the second constraint, the location of the leading singularity is determined in terms of the (LL1/x) and \\left(LLQ^2 \\right) kernels. It leads to a value significantly lower than the LL1/x evaluation, while remaining at j > 1, and compatible with the behaviour of structure functions observed at HERA.

  20. Evolution of integrated panel structural design and interfaces for PV power plants

    Science.gov (United States)

    Arnett, J. C.; Anderson, A. J.; Robertson, R. E.

    1983-01-01

    The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.

  1. Processes of lithosphere evolution: New evidence on the structure of the continental crust and uppermost mantle

    Science.gov (United States)

    Artemieva, I.M.; Mooney, W.D.; Perchuc, E.; Thybo, H.

    2002-01-01

    We discuss the structure of the continental lithosphere, its physical properties, and the mechanisms that formed and modified it since the early Archean. The structure of the upper mantle and the crust is derived primarily from global and regional seismic tomography studies of Eurasia and from global and regional data on seismic anisotropy. These data as documented in the papers of this special issue of Tectonophysics are used to illustrate the role of different tectonic processes in the lithospheric evolution since Archean to present. These include, but are not limited to, cratonization, terrane accretion and collision, continental rifting (both passive and active), subduction, and lithospheric basal erosion due to a relative motion of cratonic keels and the convective mantle. ?? 2002 Elsevier Science B.V. All rights reserved.

  2. 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.

  3. Structural evolution under uniaxial drawing of Poly(D, L-lactide) Films

    Science.gov (United States)

    Stoclet, Grégory; Lefebvre, Jean-Marc; Seguela, Roland

    2009-03-01

    Aliphatic polyesters are an important class of biodegradable polymers. They have drawn particular attention in the last few years as food packaging materials because they can be derived from renewable resources. Among this family, polylactide (PLA) is considered as one of the most promising ``green'' polymer for use as a substitute to petroleum-based polymers. In the present work, we investigate the mechanical behaviour of amorphous poly(D, L-lactide) films in relation to the structural evolution upon stretching at various draw temperatures (Td) above the glass transition temperature. Examination of the drawing behaviour shows that PLA initially behaves like a rubbery material until a true strain of the order of 1. Strain hardening occurs beyond this strain level, up to film fracture. Such strain hardening is generally ascribed to a strain induced crystallization phenomenon. In the present case, it is clearly more pronounced for Td = 90 C than for Td = 70 C. The corresponding structural evolutions are investigated by means of WAXS. The diffraction patterns reveal the marked influence of draw temperature. Indeed for Td = 70 C a mesophase is induced whereas strain-induced crystallisation takes place at Td = 90 C. Further work is in progress, in order to elucidate mesophase development and mechanical response.

  4. Liquid-Mercury-Supported Langmuir Films of Ionic Liquids: Isotherms, Structure, and Time Evolution.

    Science.gov (United States)

    Elfassy, Eitan; Mastai, Yitzhak; Pontoni, Diego; Deutsch, Moshe

    2016-04-05

    Ionic liquids have been intensively developed for the last few decades and are now used in a wide range of applications, from electrochemistry to catalysis and nanotechnology. Many of these applications involve ionic liquid interfaces with other liquids and solids, the subnanometric experimental study of which is highly demanding, and has been little studied to date. We present here a study of mercury-supported Langmuir films of imidazolium-based ionic liquids by surface tensiometry and X-ray reflectivity. The charge-delocalized ionic liquids studied here exhibit no 2D lateral order but show diffuse surface-normal electron density profiles exhibiting gradual mercury penetration into the ionic liquid film, and surface-normal structure evolution over a period of hours. The effect of increasing the nonpolar alkyl chain length was also investigated. The results obtained provide insights into the interactions between these ionic liquids and liquid mercury and about the time evolution of the structure and composition of their interface.

  5. Development of a cyber physical apparatus for investigating fluid structure interaction on leading edge vortex evolution

    Science.gov (United States)

    Raghu Gowda, Belagumba Venkatachalaiah

    This dissertation examines how simple structural compliance impacts a specific transient vortex phenomenon that occurs on high angle of attack lifting surfaces termed dynamic stall. In many Fluid structure interaction (FSI) research efforts, a purely physical or purely computational approach is taken. In this work a low cost cyber-physical (CPFD) system is designed and developed for representing the FSI in the leading edge vortex (LEV) development problem. The leading edge compliance appears to be favorable in a specific spring constant range for a given wing. When the leading edge compliance prescribed via CPFD system is too low compared with the moment due to dynamic pressure or fluid unsteady effect, the LEV behavior is similar to that of a rigid wing system. When the leading edge compliance is too high, excessive compliance is introduced into the wing system and the leading edge vortex evolution is affected by the large change in wing angle. At moderate leading edge compliance, a balance appears to be achieved in which the leading edge vorticity shedding rate supports the long term evolution of the leading edge vortex. Further investigation is required to determine specific parameters governing these leading edge compliance ranges.

  6. Evolution and dynamics of shear-layer structures in near-wall turbulence

    Science.gov (United States)

    Johansson, Arne V.; Alfredsson, P. H.; Kim, John

    1991-01-01

    Near-wall flow structures in turbulent shear flows are analyzed, with particular emphasis on the study of their space-time evolution and connection to turbulence production. The results are obtained from investigation of a database generated from direct numerical simulation of turbulent channel flow at a Reynolds number of 180 based on half-channel width and friction velocity. New light is shed on problems associated with conditional sampling techniques, together with methods to improve these techniques, for use both in physical and numerical experiments. The results clearly indicate that earlier conceptual models of the processes associated with near-wall turbulence production, based on flow visualization and probe measurements need to be modified. For instance, the development of asymmetry in the spanwise direction seems to be an important element in the evolution of near-wall structures in general, and for shear layers in particular. The inhibition of spanwise motion of the near-wall streaky pattern may be the primary reason for the ability of small longitudinal riblets to reduce turbulent skin friction below the value for a flat surface.

  7. The Structural Evolution of Milky Way-like Star Forming Galaxies since z~1.3

    CERN Document Server

    Patel, Shannon G; Franx, Marijn; van Dokkum, Pieter G; van der Wel, Arjen; Leja, Joel; Labbe, Ivo; Brammer, Gabriel; Skelton, Rosalind E; Momcheva, Ivelina; Whitaker, Katherine E; Lundgren, Britt; Muzzin, Adam; Quadri, Ryan F; Nelson, Erica June; Wake, David A; Rix, Hans-Walter

    2013-01-01

    We follow the structural evolution of star forming galaxies (SFGs) like the Milky Way by selecting progenitors to z~1.3 based on the stellar mass growth inferred from the evolution of the star forming sequence. We select our sample from the 3D-HST survey, which utilizes spectroscopy from the HST WFC3 G141 near-IR grism and enables precise redshift measurements for our sample of SFGs. Structural properties are obtained from Sersic profile fits to CANDELS WFC3 imaging. The progenitors of z=0 SFGs with stellar mass M=10^{10.5} Msun are ~2 times less massive at z~1. This late-time stellar mass assembly is consistent with recent studies that employ abundance matching techniques. The descendant SFGs at z~0 have grown in half-light radius by a factor of ~1.4 since z~1. The half-light radius grows with stellar mass as r_e M^{0.29}. While most of the stellar mass is clearly assembling at large radii, the mass surface density profiles reveal ongoing mass growth also in the central regions where bulges and pseudobulges ...

  8. Evolution of User Analysis on the Grid in ATLAS

    CERN Document Server

    Legger, Federica; The ATLAS collaboration

    2016-01-01

    More than one thousand physicists analyse data collected by the ATLAS experiment at the Large Hadron Collider (LHC) at CERN through 150 computing facilities around the world. Efficient distributed analysis requires optimal resource usage and the interplay of several factors: robust grid and software infrastructures, system capability to adapt to different workloads. The continuous automatic validation of grid sites and the user support provided by a dedicated team of expert shifters have been proven to provide a solid distributed analysis system for ATLAS users. Based on the experience from the first run of the LHC, substantial improvements to the ATLAS computing system have been made to optimize both production and analysis workflows. These include the re-design of the production and data management systems, a new analysis data format and event model, and the development of common reduction and analysis frameworks. The impact of such changes on the distributed analysis system is evaluated. More than 100 mill...

  9. Dynamic Analysis of Structures Using Neural Networks

    Directory of Open Access Journals (Sweden)

    N. Ahmadi

    2008-01-01

    Full Text Available In the recent years, neural networks are considered as the best candidate for fast approximation with arbitrary accuracy in the time consuming problems. Dynamic analysis of structures against earthquake has the time consuming process. We employed two kinds of neural networks: Generalized Regression neural network (GR and Back-Propagation Wavenet neural network (BPW, for approximating of dynamic time history response of frame structures. GR is a traditional radial basis function neural network while BPW categorized as a wavelet neural network. In BPW, sigmoid activation functions of hidden layer neurons are substituted with wavelets and weights training are achieved using Scaled Conjugate Gradient (SCG algorithm. Comparison the results of BPW with those of GR in the dynamic analysis of eight story steel frame indicates that accuracy of the properly trained BPW was better than that of GR and therefore, BPW can be efficiently used for approximate dynamic analysis of structures.

  10. Analysis of flexible structures under lateral impact

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, D. F. [Paul C. Kizzo and Associates Inc., Seismic Structural Group, Oakland, CA 94612 (United States); Razavi, H. [AREVA Inc., Civil Seismic Group, San Jose, CA 95119 (United States)

    2012-07-01

    Three methods for analysis of flexible structures under lateral impact are presented. The first proposed method (Method A) consists of: (1) modifying an available deceleration on a rigid target with conservation principles to account for structural flexibility; and (2) transient nonlinear analysis of the structure with the corrected forcing function. The second proposed method (Method B) is similar to Method A in obtaining the forcing function but it solves the equations of motion of an idealized two-degree-of-freedom system instead of directly using conservation principles. The last method simply provides the maximum force in the structure using the conservation of energy and linear momentum. A coupled simulation is also performed in LS-DYNA and compared against the proposed methods. A case study is presented to illustrate the applicability of all three methods and the LS-DYNA simulation. (authors)

  11. Object-Oriented Analysis, Structured Analysis, and Jackson System Development

    NARCIS (Netherlands)

    Wieringa, R.J.; Van Assche, F.; 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 prod

  12. THE EVOLUTION OF STATE AID IN ROMANIA. ANALYSIS OF THE AUTOMOTIVE SECTOR 2007-2015

    Directory of Open Access Journals (Sweden)

    George STEFAN

    2016-11-01

    Full Text Available This study, according to our knowledge is among the few ones dealing with the analysis of state aid impact and of the way it was used at national level. Firstly, the goal of our study is to analyze the evolution of state aid in Romania, the impact on regional development, on creating jobs and value added. Secondly it is intented to see the contribution of automotive sector which received the highest amount of state aid to the trade balance from the current account between 2008-2015. Automotive sector is a key sector for the development of Romanian economy in the last 10 years for the manufacturing and assembly of cars and for companies producing equipment or auto parts. The paper is structured in seven parts which deal with topics like the state aid in the European Union and Romania, state aid schemes and funded sectors in Romania, sectorial and geographical distribution of the state aid, the analysis of the automotive sector for Romania.

  13. 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 (pH levels, high temperature, and chemicals. These findings suggest that the proposed method is an easy way to study the molecular biophysics of protein aggregation and to rapidly screen anti-aggregation 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

  14. Structural framework and Mesozoic Cenozoic evolution of Ponta Grossa Arch, Paraná Basin, southern Brazil

    Science.gov (United States)

    Strugale, Michael; Rostirolla, Sidnei Pires; Mancini, Fernando; Portela Filho, Carlos Vieira; Ferreira, Francisco José Fonseca; de Freitas, Rafael Corrêa

    2007-09-01

    The integration of structural analyses of outcrops, aerial photographs, satellite images, aeromagnetometric data, and digital terrain models can establish the structural framework and paleostress trends related to the evolution of Ponta Grossa Arch, one of the most important structures of the Paraná Basin in southern Brazil. In the study area, the central-northern region of Paraná State, Brazil, the arch crosses outcropping areas of the Pirambóia, Botucatu, and Serra Geral Formations (São Bento Group, Mesozoic). The Pirambóia and Botucatu Formations are composed of quartz sandstones and subordinated siltstones. The Serra Geral Formation comprises tholeiitic basalt lava flows and associated intrusive rocks. Descriptive and kinematic structural analyses reveal the imprint of two brittle deformation phases: D1, controlled by the activation of an extensional system of regional faults that represent a progressive deformation that generated discontinuous brittle structures and dike swarm emplacement along a NW-SE trend, and D2, which was controlled by a strike-slip (transtensional) deformation system, probably of Late Cretaceous-Tertiary age, responsible for important fault reactivation along dykes and deformation bands in sandstones.

  15. 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

  16. 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

  17. On the structural analysis of textile composites

    Science.gov (United States)

    Bogdanovich, Alexander E.; Pastore, Christopher M.

    The local structural inhomogeneities which distinguish textile composites from laminated materials are discussed. Techniques for quantifying these inhomogeneities through three dimensional geometric modelling are introduced and methods of translating them into elastic properties are presented. Some basic ideas on application of spline functions to the stress field analysis in textile composites are proposed. The significance of internal continuity conditions for these materials is emphasized. Several analytical techniques based on the concept of a meso-volume are discussed. An example is presented to demonstrate the application of the method to structural analysis of textile composites.

  18. Evolution & Phylogenetic Analysis: Classroom Activities for Investigating Molecular & Morphological Concepts

    Science.gov (United States)

    Franklin, Wilfred A.

    2010-01-01

    In a flexible multisession laboratory, students investigate concepts of phylogenetic analysis at both the molecular and the morphological level. Students finish by conducting their own analysis on a collection of skeletons representing the major phyla of vertebrates, a collection of primate skulls, or a collection of hominid skulls.

  19. Value of Information Analysis in Structural Safety

    DEFF Research Database (Denmark)

    Konakli, Katerina; Faber, Michael Havbro

    2014-01-01

    Pre-posterior analysis can be used to assess the potential of an experiment to enhance decision making by providing information on parameters characterized by uncertainty. The present paper describes a framework for pre-posterior analysis for support of decisions related to maintenance of structu......Pre-posterior analysis can be used to assess the potential of an experiment to enhance decision making by providing information on parameters characterized by uncertainty. The present paper describes a framework for pre-posterior analysis for support of decisions related to maintenance...... of structural systems. In this context, experiments may refer to inspections or techniques of structural health monitoring. The Value of Information concept provides a powerful tool for determining whether the experimental cost is justified by the expected benefit and for identifying the optimal among different...

  20. RNA Secondary Structure Analysis Using RNAstructure.

    Science.gov (United States)

    Mathews, David H

    2014-06-17

    RNAstructure is a user-friendly program for the prediction and analysis of RNA secondary structure. It is available as a Web server, as a program with a graphical user interface, or as a set of command-line tools. The programs are available for Microsoft Windows, Macintosh OS X, or Linux. This unit provides protocols for RNA secondary structure prediction (using the Web server or the graphical user interface) and prediction of high-affinity oligonucleotide biding sites to a structured RNA target (using the graphical user interface).