WorldWideScience

Sample records for 2d pattern evolution

  1. From 2D Lithography to 3D Patterning

    NARCIS (Netherlands)

    Van Zeijl, H.W.; Wei, J.; Shen, C.; Verhaar, T.M.; Sarro, P.M.

    2010-01-01

    Lithography as developed for IC device fabrication is a high volume high accuracy patterning technology with strong 2 dimensional (2D) characteristics. This 2D nature makes it a challenge to integrate this technology in a 3 dimensional (3D) manufacturing environment. This article addresses the perfo

  2. Planar maps, circle patterns and 2d gravity

    CERN Document Server

    David, Francois

    2013-01-01

    Via circle pattern techniques, random planar triangulations (with angle variables) are mapped onto Delaunay triangulations in the complex plane. The uniform measure on triangulations is mapped onto a conformally invariant spatial point process. We show that this measure can be expressed as: (1) a sum over 3-spanning-trees partitions of the edges of the Delaunay triangulations; (2) the volume form of a K\\"ahler metric over the space of Delaunay triangulations, whose prepotential has a simple formulation in term of ideal tessellations of the 3d hyperbolic space; (3) a discretized version (involving finite difference complex derivative operators) of Polyakov's conformal Fadeev-Popov determinant in 2d gravity; (4) a combination of Chern classes, thus also establishing a link with topological 2d gravity.

  3. Evolution of Matter Wave Interference of Bose-Condensed Gas in a 2D Optical Lattice

    Institute of Scientific and Technical Information of China (English)

    XUZhi-Jun; LINGuo-Cheng; XUJun; LIZhen

    2005-01-01

    We investigate the average particle-number distribution of the atoms in the combined potential of 2D optical lattices and 31) harmonic magnetic trap based on the Gross-Pitaevskii equation. After the combined potential is switched of[, and only the optical lattice is switched off, we give the analytical results of the wavefunction of the Bosecondensed gas at any time t by using a propagator method. For both disk-shaped and cigar-shaped Bose-condensed gas,we discuss the evolution process of the central and side peaks of the interference pattern.

  4. Evolution of Matter Wave Interference of Bose-Condensed Gas in a 2D Optical Lattice

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-Jun; LIN Guo-Cheng; XU Jun; LI Zhen

    2005-01-01

    We investigate the average particle-number distribution of the atoms in the combined potential of 2D optical lattices and 3D harmonic magnetic trap based on the Gross-Pitaevskii equation. After the combined potential is switched off, and only the optical lattice is switched off, we give the analytical results of the wavefunction of the Bosecondensed gas at any time t by using a propagator method. For both disk-shaped and cigar-shaped Bose-condensed gas,we discuss the evolution process of the central and side peaks of the interference pattern.

  5. Contributions to statistical image segmentation and 2D pattern Recognition

    OpenAIRE

    Derrode, Stéphane

    2008-01-01

    This dissertation follows 9 years of my research activities, including 7 years as an assistant professor at the École Centrale Marseille and as a researcher into the Multidimensional Signal Processing Group of Institut Fresnel (CNRS UMR 6133). Works which I present explore some aspects of the statistical segmentation of images for applications in space imagery and the invariant description of 2D shapes for object recognition in video imagery. More precisely, the first part of the manuscript s...

  6. 2-D traveling-wave patterns in binary fluid convection

    Energy Technology Data Exchange (ETDEWEB)

    Surko, C.M.; Porta, A.L. [Univ. of California, La Jolla, CA (United States)

    1996-12-31

    An overview is presented of recent experiments designed to study two-dimensional traveling-wave convection in binary fluid convection in a large aspect ratio container. Disordered patterns are observed when convection is initiated. As time proceeds, they evolve to more ordered patterns, consisting of several domains of traveling-waves separated by well-defined domain boundaries. The detailed character of the patterns depends sensitively on the Rayleigh number. Numerical techniques are described which were developed to provide a quantitative characterization of the traveling-wave patterns. Applications of complex demodulation techniques are also described, which make a detailed study of the structure and dynamics of the domain boundaries possible.

  7. Layout decomposition of self-aligned double patterning for 2D random logic patterning

    Science.gov (United States)

    Ban, Yongchan; Miloslavsky, Alex; Lucas, Kevin; Choi, Soo-Han; Park, Chul-Hong; Pan, David Z.

    2011-04-01

    Self-aligned double pattering (SADP) has been adapted as a promising solution for sub-30nm technology nodes due to its lower overlay problem and better process tolerance. SADP is in production use for 1D dense patterns with good pitch control such as NAND Flash memory applications, but it is still challenging to apply SADP to 2D random logic patterns. The favored type of SADP for complex logic interconnects is a two mask approach using a core mask and a trim mask. In this paper, we first describe layout decomposition methods of spacer-type double patterning lithography, then report a type of SADP compliant layouts, and finally report SADP applications on Samsung 22nm SRAM layout. For SADP decomposition, we propose several SADP-aware layout coloring algorithms and a method of generating lithography-friendly core mask patterns. Experimental results on 22nm node designs show that our proposed layout decomposition for SADP effectively decomposes any given layouts.

  8. Short local descriptors from 2D connected pattern spectra

    NARCIS (Netherlands)

    Bosilj, Petra; Kijak, Ewa; Wilkinson, Michael H. F.; Lefèvre, Sebastien

    2015-01-01

    We propose a local region descriptor based on connected pattern spectra, and combined with normalized central moments. The descriptors are calculated for MSER regions of the image, and their performance compared against SIFT. The MSER regions were chosen because they can be efficiently selected by c

  9. Groupware requirements evolution patterns

    NARCIS (Netherlands)

    Pumareja, Dulce Trinidad

    2013-01-01

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

  10. Fast Computation of Wideband Beam Pattern for Designing Large-Scale 2-D Arrays.

    Science.gov (United States)

    Chi, Cheng; Li, Zhaohui

    2016-06-01

    For real-time and high-resolution 3-D ultrasound imaging, the design of sparse distribution and weights of elements of a large-scale wideband 2-D array is needed to reduce hardware cost and achieve better directivity. However, due to the high time consumption of computing the wideband beam pattern, the design methods that need massive iterations have rarely been applied to design large-scale wideband 2-D arrays by directly computing the wideband beam pattern. In this paper, a fast method is proposed to realize the computation of a wideband beam pattern of arbitrary 2-D arrays in the far field in order to design large-scale wideband 2-D arrays. The proposed fast method exploits two important techniques: 1) nonuniform fast Fourier transform (FFT) and 2) short inverse FFT. Compared with the commonly used ultrasound simulator Field II, two orders of magnitude improvement in computation speed is achieved with comparable accuracy. The proposed fast method enables massive iterations of direct wideband beam pattern computation of arbitrary large-scale 2-D arrays. A design example in this paper demonstrates that the proposed fast method can help achieve better performance in designing large-scale wideband 2-D arrays. PMID:27046870

  11. Groupware requirements evolution patterns

    OpenAIRE

    Pumareja, Dulce Trinidad

    2013-01-01

    Requirements evolution is a generally known problem in software development. Requirements are known to change all throughout a system's lifecycle. Nevertheless, requirements evolution is a poorly understood phenomenon. Most studies on requirements evolution focus on changes to written specifications and on software architecture and design. Usually, the focus is when the software is under development. Little is known about how requirements evolve when software is put into use. Groupware is an ...

  12. EVOLUTION OF A 2-D DISTURBANCE IN A SUPERSONIC BOUNDARY LAYER AND THE GENERATION OF SHOCKLETS

    Institute of Scientific and Technical Information of China (English)

    黄章峰; 周恒

    2004-01-01

    Through direct numerical simulation, the evolution of a 2-D disturbance in a supersonic boundary layer has been investigated. At a chosen location, a small amplitude T-S wave was fed into the boundary layer to investigate its evolution. Characteristics of nonlinear evolution have been found. Two methods were applied for the detection of shocklets ,and it was found that when the amplitude of the disturbance reached a certain value,shocklets would be generated, which should be taken into consideration when nonlinear theory of hydrodynamic stability for compressible flows is to be established.

  13. 2D pattern evolution constrained by complex network dynamics

    CERN Document Server

    Rocha, L E C; Costa, Luciano da Fontoura; Rocha, Luis Enrique Correa da

    2006-01-01

    Complex networks have established themselves along the last years as being particularly suitable and flexible for representing and modeling several complex natural and human-made systems. At the same time in which the structural intricacies of such networks are being revealed and understood, efforts have also been directed at investigating how such connectivity properties define and constrain the dynamics of systems unfolding on such structures. However, lesser attention has been focused on hybrid systems, \\textit{i.e.} involving more than one type of network and/or dynamics. Because several real systems present such an organization (\\textit{e.g.} the dynamics of a disease coexisting with the dynamics of the immune system), it becomes important to address such hybrid systems. The current paper investigates a specific system involving a diffusive (linear and non-linear) dynamics taking place in a regular network while interacting with a complex network of defensive agents following Erd\\"os-R\\'enyi and Barab\\'a...

  14. 2 D patterns of soil gas diffusivity , soil respiration, and methane oxidation in a soil profile

    Science.gov (United States)

    Maier, Martin; Schack-Kirchner, Helmer; Lang, Friederike

    2015-04-01

    The apparent gas diffusion coefficient in soil (DS) is an important parameter describing soil aeration, which makes it a key parameter for root growth and gas production and consumption. Horizontal homogeneity in soil profiles is assumed in most studies for soil properties - including DS. This assumption, however, is not valid, even in apparently homogeneous soils, as we know from studies using destructive sampling methods. Using destructive methods may allow catching a glimpse, but a large uncertainty remains, since locations between the sampling positions cannot be analyzed, and measurements cannot be repeated. We developed a new method to determine in situ the apparent soil gas diffusion coefficient in order to examine 2 D pattern of DS and methane oxidation in a soil profile. Different tracer gases (SF6, CF4, C2H6) were injected continuously into the subsoil and measured at several locations in the soil profile. These data allow for modelling inversely the 2 D patterns of DS using Finite Element Modeling. The 2D DS patterns were then combined with naturally occurring CH4 and CO2 concentrations sampled at the same locations to derive the 2D pattern of soil respiration and methane oxidation in the soil profile. We show that methane oxidation and soil respiration zones shift within the soil profile while the gas fluxes at the surface remain rather stable during a the 3 week campaign.

  15. Stochastic 2-D Models of Galaxy Disk Evolution. The Galaxy M33

    OpenAIRE

    Mineikis, Tadas; Vansevičius, Vladas

    2015-01-01

    We have developed a fast numerical 2-D model of galaxy disk evolution (resolved along the galaxy radius and azimuth) by adopting a scheme of parameterized stochastic self-propagating star formation. We explore the parameter space of the model and demonstrate its capability to reproduce 1-D radial profiles of the galaxy M33: gas surface density, surface brightness in the i and GALEX FUV passbands, and metallicity.

  16. Small-amplitude 2D patterns with nontrivial symmetry in a simple nonlinear field model

    International Nuclear Information System (INIS)

    Quasiperiodic (QP) small-amplitude patterns are studied in a scalar field theory with quadratic nonlinearity. QP solutions of the class in interest are found as a projection of strictly periodic solutions of an associated 4D problem onto an 'irrationally oriented' 2D subspace. The periodic solutions of the 4D problem are constructed using a version of the method of asymptotic expansions. The analysis reveals complex patterns. In particular, there exists a one-parametric QP pattern with strict 12-fold symmetry, which contains infinitely many local patches with approximate 5-fold symmetry. In limit cases, the complex patterns transform into a simple pattern: a close pack of hexagonal cells. In certain resonance cases there exist patterns consisting of alternating pieces of close cell packs with either hexagonal or quadrangular symmetry. The relation between the 12-fold and 5-fold approximate symmetries is discussed. (author)

  17. Removal of Spectro-Polarimetric Fringes by 2D Pattern Recognition

    OpenAIRE

    Casini, R.; Judge, P. G.; Schad, T. A.

    2012-01-01

    We present a pattern-recognition based approach to the problem of removal of polarized fringes from spectro-polarimetric data. We demonstrate that 2D Principal Component Analysis can be trained on a given spectro-polarimetric map in order to identify and isolate fringe structures from the spectra. This allows us in principle to reconstruct the data without the fringe component, providing an effective and clean solution to the problem. The results presented in this paper point in the direction...

  18. Prolegomenon to patterns in evolution.

    Science.gov (United States)

    Kauffman, Stuart A

    2014-09-01

    Despite Darwin, we remain children of Newton and dream of a grand theory that is epistemologically complete and would allow prediction of the evolution of the biosphere. The main purpose of this article is to show that this dream is false, and bears on studying patterns of evolution. To do so, I must justify the use of the word "function" in biology, when physics has only happenings. The concept of "function" lifts biology irreducibly above physics, for as we shall see, we cannot prestate the ever new biological functions that arise and constitute the very phase space of evolution. Hence, we cannot mathematize the detailed becoming of the biosphere, nor write differential equations for functional variables we do not know ahead of time, nor integrate those equations, so no laws "entail" evolution. The dream of a grand theory fails. In place of entailing laws, I propose a post-entailing law explanatory framework in which Actuals arise in evolution that constitute new boundary conditions that are enabling constraints that create new, typically unprestatable, adjacent possible opportunities for further evolution, in which new Actuals arise, in a persistent becoming. Evolution flows into a typically unprestatable succession of adjacent possibles. Given the concept of function, the concept of functional closure of an organism making a living in its world becomes central. Implications for patterns in evolution include historical reconstruction, and statistical laws such as the distribution of extinction events, or species per genus, and the use of formal cause, not efficient cause, laws.

  19. Film flows and self-organized patterns of 2D-localized structures

    Energy Technology Data Exchange (ETDEWEB)

    Frenkel, A.L. [Univ. of Alabama, Tuscaloosa, AL (United States)

    1996-12-31

    Films flowing down an inclined plane are considered. An unconventional perturbation approach is discussed. It yields the most general evolution equation for film thickness and the least restrictive conditions for its validity. Results of numerical simulations of the dissipative-dispersive evolution equation indicate that novel, more complex type of spatiotemporal patterns can exist for strange attractors of nonequilibrium systems. It is suggested that real-life experiments satisfying the validity conditions of this theory are possible.

  20. 2D cellular automaton model for the evolution of active region coronal plasmas

    CERN Document Server

    Fuentes, Marcelo López

    2016-01-01

    We study a 2D cellular automaton (CA) model for the evolution of coronal loop plasmas. The model is based on the idea that coronal loops are made of elementary magnetic strands that are tangled and stressed by the displacement of their footpoints by photospheric motions. The magnetic stress accumulated between neighbor strands is released in sudden reconnection events or nanoflares that heat the plasma. We combine the CA model with the Enthalpy Based Thermal Evolution of Loops (EBTEL) model to compute the response of the plasma to the heating events. Using the known response of the XRT telescope on board Hinode we also obtain synthetic data. The model obeys easy to understand scaling laws relating the output (nanoflare energy, temperature, density, intensity) to the input parameters (field strength, strand length, critical misalignment angle). The nanoflares have a power-law distribution with a universal slope of -2.5, independent of the input parameters. The repetition frequency of nanoflares, expressed in t...

  1. Removal of Spectro-Polarimetric Fringes by 2D Pattern Recognition

    CERN Document Server

    Casini, R; Schad, T A

    2012-01-01

    We present a pattern-recognition based approach to the problem of removal of polarized fringes from spectro-polarimetric data. We demonstrate that 2D Principal Component Analysis can be trained on a given spectro-polarimetric map in order to identify and isolate fringe structures from the spectra. This allows us in principle to reconstruct the data without the fringe component, providing an effective and clean solution to the problem. The results presented in this paper point in the direction of revising the way that science and calibration data should be planned for a typical spectro-polarimetric observing run.

  2. Patterned Peeling 2D MoS2 off the Substrate.

    Science.gov (United States)

    Zhao, Jing; Yu, Hua; Chen, Wei; Yang, Rong; Zhu, Jianqi; Liao, Mengzhou; Shi, Dongxia; Zhang, Guangyu

    2016-07-01

    The performance of two-dimensional (2D) MoS2 devices depends largely on the quality of the MoS2 itself. Existing fabrication process for 2D MoS2 relies on lithography and etching. However, it is extremely difficult to achieve clean patterns without any contaminations or passivations. Here we report a peel-off pattering of MoS2 films on substrates based on a proper interface engineering. The peel-off process utilizes the strong adhesion between gold and MoS2 and removes the MoS2 film contact with gold directly, leading to clean MoS2 pattern generation without residuals. Significantly improved electrical performances including high mobility ∼17.1 ± 8.3 cm(2)/(V s) and on/off ratio ∼5.6 ± 3.6 × 10(6) were achieved. Such clean fabrication technique paves a way to high quality MoS2 devices for various electrical and optical applications.

  3. Patterned Peeling 2D MoS2 off the Substrate.

    Science.gov (United States)

    Zhao, Jing; Yu, Hua; Chen, Wei; Yang, Rong; Zhu, Jianqi; Liao, Mengzhou; Shi, Dongxia; Zhang, Guangyu

    2016-07-01

    The performance of two-dimensional (2D) MoS2 devices depends largely on the quality of the MoS2 itself. Existing fabrication process for 2D MoS2 relies on lithography and etching. However, it is extremely difficult to achieve clean patterns without any contaminations or passivations. Here we report a peel-off pattering of MoS2 films on substrates based on a proper interface engineering. The peel-off process utilizes the strong adhesion between gold and MoS2 and removes the MoS2 film contact with gold directly, leading to clean MoS2 pattern generation without residuals. Significantly improved electrical performances including high mobility ∼17.1 ± 8.3 cm(2)/(V s) and on/off ratio ∼5.6 ± 3.6 × 10(6) were achieved. Such clean fabrication technique paves a way to high quality MoS2 devices for various electrical and optical applications. PMID:27314173

  4. 2D Transition-Metal-Dichalcogenide-Nanosheet-Based Composites for Photocatalytic and Electrocatalytic Hydrogen Evolution Reactions.

    Science.gov (United States)

    Lu, Qipeng; Yu, Yifu; Ma, Qinglang; Chen, Bo; Zhang, Hua

    2016-03-01

    Hydrogen (H2) is one of the most important clean and renewable energy sources for future energy sustainability. Nowadays, photocatalytic and electrocatalytic hydrogen evolution reactions (HERs) from water splitting are considered as two of the most efficient methods to convert sustainable energy to the clean energy carrier, H2. Catalysts based on transition metal dichalcogenides (TMDs) are recognized as greatly promising substitutes for noble-metal-based catalysts for HER. The photocatalytic and electrocatalytic activities of TMD nanosheets for the HER can be further improved after hybridization with many kinds of nanomaterials, such as metals, oxides, sulfides, and carbon materials, through different methods including the in situ reduction method, the hot-injection method, the heating-up method, the hydro(solvo)thermal method, chemical vapor deposition (CVD), and thermal annealing. Here, recent progress in photocatalytic and electrocatalytic HERs using 2D TMD-based composites as catalysts is discussed. PMID:26676800

  5. 2D-patterning of self-assembled silver nanoisland films.

    Science.gov (United States)

    Chervinskii, Semen; Reduto, Igor; Kamenskii, Alexander; Mukhin, Ivan S; Lipovskii, Andrey A

    2016-04-12

    The paper is dedicated to the recently developed by the authors technique of silver nanoisland growth, allowing self-arrangement of 2D-patterns of nanoislands. The technique employs silver out-diffusion from ion-exchanged glass in the course of annealing in hydrogen. To modify the silver ion distribution in the exchanged soda-lime glass we included the thermal poling of the ion-exchanged glass with a profiled electrode as an intermediate stage of the process. The resulting consequence consists of three steps: (i) during the ion exchange of the glass in the AgxNa1-xNO3 (x = 0.01-0.15) melt we enrich the subsurface layer of the glass with silver ions; (ii) under the thermal poling, the electric field displaces these ions deeper into the glass under the 2D profiled anodic electrode, the displacement is smaller under the hollows in the electrode where the intensity of the field is minimal; (iii) annealing in a reducing atmosphere of hydrogen results in silver out-diffusion only in the regions corresponding to the electrode hollows, as a result silver forms nanoislands following the shape of the electrode. Varying the electrode and mode of processing allows governing the nanoisland size distribution and self-arrangement of the isolated single nanoislands, pairs, triples or groups of several nanoislands-so-called plasmonic molecules. PMID:26765367

  6. Non-linear evolution of the diocotron instability in a pulsar electrosphere: 2D PIC simulations

    CERN Document Server

    Petri, J

    2009-01-01

    (abridged) The physics of the pulsar magnetosphere near the neutron star surface remains poorly constrained by observations. Nevertheless it is believed that large vacuum gaps exist in the magnetosphere, and a non-neutral plasma partially fills the neutron star surroundings to form an electrosphere. The equatorial disk in this electrosphere is diocotron and magnetron unstable. To better assess the long term evolution of these instabilities, we study the behavior of the non-neutral plasma with help on particle simulations. We designed a 2D electrostatic PIC code. In the diocotron regime, the equation of motion for particles obeys the electric drift approximation. The plasma is confined between two conducting walls. Moreover, in order to simulate a pair cascade in the gaps, we add a source term feeding the plasma with charged particles. We consider the long term non-linear evolution of the diocotron instability. We found that particles tend to attract together to form small vortex of high charge density rotatin...

  7. Design and testing of the first 2D Prototype Vertically Integrated Pattern Recognition Associative Memory

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.; Deptuch, G.; Hoff, J.; Jindariani, S.; Joshi, S.; Olsen, J.; Tran, N.; Trimpl, M.

    2015-02-01

    An associative memory-based track finding approach has been proposed for a Level 1 tracking trigger to cope with increasing luminosities at the LHC. The associative memory uses a massively parallel architecture to tackle the intrinsically complex combinatorics of track finding algorithms, thus avoiding the typical power law dependence of execution time on occupancy and solving the pattern recognition in times roughly proportional to the number of hits. This is of crucial importance given the large occupancies typical of hadronic collisions. The design of an associative memory system capable of dealing with the complexity of HL-LHC collisions and with the short latency required by Level 1 triggering poses significant, as yet unsolved, technical challenges. For this reason, an aggressive R&D program has been launched at Fermilab to advance state of-the-art associative memory technology, the so called VIPRAM (Vertically Integrated Pattern Recognition Associative Memory) project. The VIPRAM leverages emerging 3D vertical integration technology to build faster and denser Associative Memory devices. The first step is to implement in conventional VLSI the associative memory building blocks that can be used in 3D stacking, in other words, the building blocks are laid out as if it is a 3D design. In this paper, we report on the first successful implementation of a 2D VIPRAM demonstrator chip (protoVIPRAM00). The results show that these building blocks are ready for 3D stacking.

  8. Dead Reckoning Using Play Patterns in a Simple 2D Multiplayer Online Game

    Directory of Open Access Journals (Sweden)

    Wei Shi

    2014-01-01

    Full Text Available In today’s gaming world, a player expects the same play experience whether playing on a local network or online with many geographically distant players on congested networks. Because of delay and loss, there may be discrepancies in the simulated environment from player to player, likely resulting in incorrect perception of events. It is desirable to develop methods that minimize this problem. Dead reckoning is one such method. Traditional dead reckoning schemes typically predict a player’s position linearly by assuming players move with constant force or velocity. In this paper, we consider team-based 2D online action games. In such games, player movement is rarely linear. Consequently, we implemented such a game to act as a test harness we used to collect a large amount of data from playing sessions involving a large number of experienced players. From analyzing this data, we identified play patterns, which we used to create three dead reckoning algorithms. We then used an extensive set of simulations to compare our algorithms with the IEEE standard dead reckoning algorithm and with the recent “Interest Scheme” algorithm. Our results are promising especially with respect to the average export error and the number of hits.

  9. Improved 2D Intelligent Driver Model simulating synchronized flow and evolution concavity in traffic flow

    CERN Document Server

    Tian, Junfang; Li, Geng; Treiber, Martin; Zhu, Chenqiang; Jia, Bin

    2016-01-01

    This paper firstly show that 2 Dimensional Intelligent Driver Model (Jiang et al., PloS one, 9(4), e94351, 2014) is not able to replicate the synchronized traffic flow. Then we propose an improved model by considering the difference between the driving behaviors at high speeds and that at low speeds. Simulations show that the improved model can reproduce the phase transition from synchronized flow to wide moving jams, the spatiotemporal patterns of traffic flow induced by traffic bottleneck, and the evolution concavity of traffic oscillations (i.e. the standard deviation of the velocities of vehicles increases in a concave/linear way along the platoon). Validating results show that the empirical time series of traffic speed obtained from Floating Car Data can be well simulated as well.

  10. Bottom-up design of 2D organic photocatalysts for visible-light driven hydrogen evolution

    International Nuclear Information System (INIS)

    To design two-dimensional (2D) organocatalysts, three series of covalent organic frameworks (COFs) are constructed using bottom-up strategies, i.e. molecular selection, tunable linkage, and functionalization. First-principles calculations are performed to confirm their photocatalytic activity under visible light. Two of our constructed 2D COF models (B1 and C3) are identified as a sufficiently efficient organocatalyst for visible light water splitting. The controllable construction of such COFs from suitable organic subunit, linkage, and functional groups paves the way for correlating band edge alignments and geometry parameters of 2D organic materials. Our theoretical prediction not only provides essential insights into designing 2D-COF photocatalysts for water splitting, but also sparks other technological applications for 2D organic materials. (paper)

  11. High Luminescence White LEDs Prepared with 2D Island-Pattern of Quantum Dots Dispersed Photopolymer Films

    Directory of Open Access Journals (Sweden)

    Hyun-Guk Hong

    2015-01-01

    Full Text Available Since the reabsorption loss among different size quantum dots (QDs is a critical issue in the QD based white LEDs, we proposed and fabricated new film structure of 2D island-patterns consisting of separate green and red QDs dispersed photopolymer patterns in a zigzag form. A small air-gap such as 60 μm between QD islands helps to control the optical path at the interface to reduce the lateral reabsorption loss to enhance the optical efficiency of white LED. The 2D island-patterns of QD phosphor film were fabricated using a UV imprinting process and compared the optical efficiency with the other QD film structure prepared with same QD concentrations and thicknesses such as a mixed and separately layered QD structure. Experimental and simulation analysis were performed to confirm the better optical efficiency from the 2D island-patterns of QD films due to the reduced reabsorption loss. High luminescence white LED was finally realized with 2D island-patterns of QD film, resulting in a luminous efficiency of 62.2 lm/W and CRI of 83 with CCT of 4537 K at the operation current of 60 mA.

  12. 2D nanosheet molybdenum disulphide (MoS2) modified electrodes explored towards the hydrogen evolution reaction

    Science.gov (United States)

    Rowley-Neale, Samuel J.; Brownson, Dale A. C.; Smith, Graham C.; Sawtell, David A. G.; Kelly, Peter J.; Banks, Craig E.

    2015-10-01

    We explore the use of two-dimensional (2D) MoS2 nanosheets as an electrocatalyst for the Hydrogen Evolution Reaction (HER). Using four commonly employed commercially available carbon based electrode support materials, namely edge plane pyrolytic graphite (EPPG), glassy carbon (GC), boron-doped diamond (BDD) and screen-printed graphite electrodes (SPE), we critically evaluate the reported electrocatalytic performance of unmodified and MoS2 modified electrodes towards the HER. Surprisingly, current literature focuses almost exclusively on the use of GC as an underlying support electrode upon which HER materials are immobilised. 2D MoS2 nanosheet modified electrodes are found to exhibit a coverage dependant electrocatalytic effect towards the HER. Modification of the supporting electrode surface with an optimal mass of 2D MoS2 nanosheets results in a lowering of the HER onset potential by ca. 0.33, 0.57, 0.29 and 0.31 V at EPPG, GC, SPE and BDD electrodes compared to their unmodified counterparts respectively. The lowering of the HER onset potential is associated with each supporting electrode's individual electron transfer kinetics/properties and is thus distinct. The effect of MoS2 coverage is also explored. We reveal that its ability to catalyse the HER is dependent on the mass deposited until a critical mass of 2D MoS2 nanosheets is achieved, after which its electrocatalytic benefits and/or surface stability curtail. The active surface site density and turn over frequency for the 2D MoS2 nanosheets is determined, characterised and found to be dependent on both the coverage of 2D MoS2 nanosheets and the underlying/supporting substrate. This work is essential for those designing, fabricating and consequently electrochemically testing 2D nanosheet materials for the HER.We explore the use of two-dimensional (2D) MoS2 nanosheets as an electrocatalyst for the Hydrogen Evolution Reaction (HER). Using four commonly employed commercially available carbon based electrode

  13. 2D nanosheet molybdenum disulphide (MoS2) modified electrodes explored towards the hydrogen evolution reaction.

    Science.gov (United States)

    Rowley-Neale, Samuel J; Brownson, Dale A C; Smith, Graham C; Sawtell, David A G; Kelly, Peter J; Banks, Craig E

    2015-11-21

    We explore the use of two-dimensional (2D) MoS2 nanosheets as an electrocatalyst for the Hydrogen Evolution Reaction (HER). Using four commonly employed commercially available carbon based electrode support materials, namely edge plane pyrolytic graphite (EPPG), glassy carbon (GC), boron-doped diamond (BDD) and screen-printed graphite electrodes (SPE), we critically evaluate the reported electrocatalytic performance of unmodified and MoS2 modified electrodes towards the HER. Surprisingly, current literature focuses almost exclusively on the use of GC as an underlying support electrode upon which HER materials are immobilised. 2D MoS2 nanosheet modified electrodes are found to exhibit a coverage dependant electrocatalytic effect towards the HER. Modification of the supporting electrode surface with an optimal mass of 2D MoS2 nanosheets results in a lowering of the HER onset potential by ca. 0.33, 0.57, 0.29 and 0.31 V at EPPG, GC, SPE and BDD electrodes compared to their unmodified counterparts respectively. The lowering of the HER onset potential is associated with each supporting electrode's individual electron transfer kinetics/properties and is thus distinct. The effect of MoS2 coverage is also explored. We reveal that its ability to catalyse the HER is dependent on the mass deposited until a critical mass of 2D MoS2 nanosheets is achieved, after which its electrocatalytic benefits and/or surface stability curtail. The active surface site density and turn over frequency for the 2D MoS2 nanosheets is determined, characterised and found to be dependent on both the coverage of 2D MoS2 nanosheets and the underlying/supporting substrate. This work is essential for those designing, fabricating and consequently electrochemically testing 2D nanosheet materials for the HER.

  14. EXPRESSION PATTERN OF LUNG CANCER RELATED GENES IN MALIGNANT TRANSFORMATION OF BEP2D

    Institute of Scientific and Technical Information of China (English)

    范保星; 张开泰; 李刚; 谢玲; 马淑华; 葛世丽; 项小琼; 胡迎春; 王升启; 周平坤; 吴德昌

    2002-01-01

    Objective: To detect the expression difference of 60 lung cancer associated genes in human bronchial epithelial malignant transformation cell model (BEP2D) induced by alpha-particles. Methods: 60 lung cancer associated genes were collected and micro-arrayed onto the microscope slides using Cartesian PixSys5500 cDNA Microarray machine. Total RNA from BEP2D cells and passage 20 (Rl5H-20), passage 35 (R15H-35) cells derived from BEP2D following 1.5 Gy alpha-particles was extracted and labeled by fluorescent dye. The labeled probe was then hybridized with the cDNA. Results: 40, 47, 20 genes were detected in BEP2D, R15H-20 and R15H-35 respectively. The expression level of tumor suppressor genes decreased greatly in the transformed R15H-35. Most oncogenes decreased slightly in R15H-20. Most growth factors expressed only in R15H-20. Conclusion: In human bronchial epithelial malignant transformed cell model generated by alpha-particles, the loss-function of tumor suppressor genes at initiation stage was dominant, some related oncogenes and growth factors promoted the malignant transformation.

  15. A physical pattern recognition approach for 2D electromagnetic induction studies

    Directory of Open Access Journals (Sweden)

    D. Patella

    2000-06-01

    Full Text Available We present a new tomographic procedure for the analysis of natural source electromagnetic (EM induction field data collected over any complex 2D buried structure beneath a flat air-earth boundary. The tomography is developed in a pure physical context and the primary goal is the depiction of the space distribution of two occurrence probability functions for the induced electrical charge accumulations on resistivity discontinuities and current channelling inside conductive bodies, respectively. The procedure to obtain tomographic image consists of a scanning operation governed analytically by a set of multiple interference cross-correlations between the observed EM components and the corresponding synthetic components of a pair of elementary charge and dipole. To show the potentiality of the proposed physical tomography, we discuss the results from three 2D synthetic examples.

  16. Phenols content and 2-D electrophoresis protein pattern: a promising tool to monitor Posidonia meadows health state

    Directory of Open Access Journals (Sweden)

    Randazzo Davide

    2007-07-01

    Full Text Available Abstract Background The endemic seagrass Posidonia oceanica (L. Delile colonizes soft bottoms producing highly productive meadows that play a crucial role in coastal ecosystems dynamics. Human activities and natural events are responsible for a widespread meadows regression; to date the identification of "diagnostic" tools to monitor conservation status is a critical issue. In this study the feasibility of a novel tool to evaluate ecological impacts on Posidonia meadows has been tested. Quantification of a putative stress indicator, i.e. phenols content, has been coupled to 2-D electrophoretic protein analysis of rhizome samples. Results The overall expression pattern from Posidonia rhizome was determined using a preliminary proteomic approach, 437 protein spots were characterized by pI and molecular weight. We found that protein expression differs in samples belonging to sites with high or low phenols: 22 unique protein spots are peculiar of "low phenols" and 27 other spots characterize "high phenols" samples. Conclusion Posidonia showed phenols variations within the meadow, that probably reflect the heterogeneity of environmental pressures. In addition, comparison of the 2-D electrophoresis patterns allowed to highlight qualitative protein expression differences in response to these pressures. These differences may account for changes in metabolic/physiological pathways as adaptation to stress. A combined approach, based on phenols content determination and 2-D electrophoresis protein pattern, seems a promising tool to monitor Posidonia meadows health state.

  17. NUMERICAL TESTS ON PATTERN FORMATION IN 2D HETEROGENEOUS MEDIUMS: AN APPROACH USING THE SCHNAKENBERG MODEL

    OpenAIRE

    Diego A. Garzón-Alvarado; CARLOS GALEANO; JUAN MANTILLA

    2012-01-01

    Este articulo presenta distintas pruebas numéricas en dominios que presenta variación de parámetros, de forma espacial, de la ecuación de reacción- difusión en el espacio de Turing. Las pruebas son desarrolladas en cuadrados de lado unitario 2D en el cual se realizan subdivisiones (subdominios). En cada subdomminio se ingresan parámetros que corresponden a los diferentes números de onda, por lo tanto presentan un medio heterogéneo. Cada número de onda fue predicho mediante la teoría lineal de...

  18. 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...

  19. 2D spiral pattern recognition based on neural network covering algorithm

    Institute of Scientific and Technical Information of China (English)

    HUANG Guo-hong; XIONG Zhi-hua; SHAO Hui-he

    2007-01-01

    The main aim for a 2D spiral recognition algorithm is to learn to discriminate between data distributed on two distinct strands in the x - y plane. This problem is of critical importance since it incorporates temporal characteristics often found in real-time applications. Previous work with this benchmark has witnessed poor results with statistical methods such as discriminant analysis and tedious procedures for better results with neural networks. This paper presents a max-density covering learning algorithm based on constructive neural networks which is efficient in terms of the recognition rate and the speed of recognition. The results show that it is possible to solve the spiral problem instantaneously (up to 100% correct classification on the test set).

  20. The algorithm of decomposing superimposed 2-D Poisson processes and its application to the extracting earthquake clustering pattern

    Institute of Scientific and Technical Information of China (English)

    裴韬; 周成虎; 杨明; 骆剑承; 李全林

    2004-01-01

    Aiming at the complexity of seismic gestation mechanism and spatial distribution, we hypothesize that the seismic data are composed of background earthquakes and anomaly earthquakes in a certain temporal-spatial scope. Also the background earthquakes and anomaly earthquakes both satisfy the 2-D Poisson process of different parameters respectively. In the paper, the concept of N-th order distance is introduced in order to transform 2-D superimposed Poisson process into 1-D mixture density function. On the basis of choosing the distance, mixture density function is decomposed to recognize the anomaly earthquakes through genetic algorithm. Combined with the temporal scanning of C value, the algorithm is applied to the recognition on spatial pattern of foreshock anomalies by examples of Songpan and Longling sequences in the southwest of China.

  1. Multilevel image thresholding based on 2D histogram and maximum Tsallis entropy--a differential evolution approach.

    Science.gov (United States)

    Sarkar, Soham; Das, Swagatam

    2013-12-01

    Multilevel thresholding amounts to segmenting a gray-level image into several distinct regions. This paper presents a 2D histogram based multilevel thresholding approach to improve the separation between objects. Recent studies indicate that the results obtained with 2D histogram oriented approaches are superior to those obtained with 1D histogram based techniques in the context of bi-level thresholding. Here, a method to incorporate 2D histogram related information for generalized multilevel thresholding is proposed using the maximum Tsallis entropy. Differential evolution (DE), a simple yet efficient evolutionary algorithm of current interest, is employed to improve the computational efficiency of the proposed method. The performance of DE is investigated extensively through comparison with other well-known nature inspired global optimization techniques such as genetic algorithm, particle swarm optimization, artificial bee colony, and simulated annealing. In addition, the outcome of the proposed method is evaluated using a well known benchmark--the Berkley segmentation data set (BSDS300) with 300 distinct images. PMID:23955760

  2. The Meandering-Braided River Pattern Transition Explained Empirically and with a 2D Morphodynamics Model

    Science.gov (United States)

    van den Berg, J. H.; Schuurman, F.; Kleinhans, M. G.; Lentink, H.

    2010-12-01

    Our objective is to understand general causes of different river channel patterns in unconfined alluvial plains. We discuss the principles and compare the performance of an empirical stream power-based classification and a physics-based bar pattern predictor. We present a careful selection of data from literature that contains rivers with discharge and median bed particle size ranging several orders of magnitude with various channel patterns and bar types, but no obvious eroding or aggrading tendency. Empirically a continuum of patterns is found for increasing specific stream power from single-thread, laterally immobile channels, meandering styles with scroll bars and with chute bars and moderately and highly braided channel patterns. Stream power is calculated with pattern-independent variables: mean annual flood, valley gradient and channel width predicted with a hydraulic geometry relation. `Thresholds', above which these patterns emerge, increase with bed sediment size. Linear bar theory predicts nature and presence of bars and bar mode, here converted to active braiding index. The most important variables are actual width-to-depth ratio and nonlinearity of bed sediment transport. Numerical modelling with the same equations as underlying the bar theory allow for nonlinear effects. We modelled hypothetical rivers over a large range of stream power and particle sizes with various choices for hydraulic roughness, sediment transport and transverse slope relations. Results agree well with the empirical diagram as well as empirical relations for bar and channel dimensions. Increasing potential specific stream power implies more energy to erode banks and indeed correlates to channels with high width-to-depth ratio. Bar theory and numerical modelling predict that such rivers develop more bars across the width (higher braiding index). At the transition from meandering to braiding weakly braided rivers and meandering rivers with chutes are found in nature and in the

  3. Concurrent grammar inference machines for 2-D pattern recognition: a comparison with the level set approach

    Science.gov (United States)

    Lam, K. P.; Fletcher, P.

    2009-02-01

    Parallel processing promises scalable and effective computing power which can handle the complex data structures of knowledge representation languages efficiently. Past and present sequential architectures, despite the rapid advances in computing technology, have yet to provide such processing power and to offer a holistic solution to the problem. This paper presents a fresh attempt in formulating alternative techniques for grammar learning, based upon the parallel and distributed model of connectionism, to facilitate the more cognitively demanding task of pattern understanding. The proposed method has been compared with the contemporary approach of shape modelling based on level sets, and demonstrated its potential as a prototype for constructing robust networks on high performance parallel platforms.

  4. Patterns and Processes of Vertebrate Evolution

    Science.gov (United States)

    Carroll, Robert Lynn

    1997-04-01

    This new text provides an integrated view of the forces that influence the patterns and rates of vertebrate evolution from the level of living populations and species to those that resulted in the origin of the major vertebrate groups. The evolutionary roles of behavior, development, continental drift, and mass extinctions are compared with the importance of variation and natural selection that were emphasized by Darwin. It is extensively illustrated, showing major transitions between fish and amphibians, dinosaurs and birds, and land mammals to whales. No book since Simpson's Major Features of Evolution has attempted such a broad study of the patterns and forces of evolutionary change. Undergraduate students taking a general or advanced course on evolution, and graduate students and professionals in evolutionary biology and paleontology will find the book of great interest.

  5. Topological evolution during coupled grain growth and Ostwald ripening in volume-conserved 2-D two-phase polycrystals

    International Nuclear Information System (INIS)

    The topological evolution during coupled grain growth and Ostwald ripening in volume-conserved two-phase polycrystalline systems was studied in two dimensions (2-D), employing computer simulations based on a continuum diffuse-interface field model. The topological distributions were found to scale with time, but dependent on the ratios of grain boundary energies to the interphase boundary energy, the volume fractions and the initial microstructures. The correlations between topological class and grain size, as well as the topological correlations of grains with their neighbor grains were observed. The differences in topological features between volume-conserved two-phase systems and single-phase systems are discussed for ZrO2 and Al2O3 phases

  6. Does the Medication Pattern Reflect the CYP2D6 Genotype in Patients With Diagnoses Within the Schizophrenic Spectrum?

    DEFF Research Database (Denmark)

    Jürgens, Gesche; Rasmussen, Henrik B; Werge, Thomas;

    2012-01-01

    Cytochrome P450 2D6 enzyme (CYP2D6) is an important metabolic pathway for many antipsychotics. Its genetic polymorphism causes pharmacokinetic variability that might lead to adverse drug reactions or treatment failure unless countered by appropriate dose adjustments or shift to CYP2D6-independent...

  7. Orbital evolution of colliding star and pulsar winds in 2D and 3D: dimensionality, resolution, and grid size effects

    CERN Document Server

    Bosch-Ramon, V; Perucho, M

    2014-01-01

    The structure formed by the shocked winds of a massive star and a non-accreting pulsar in a binary system suffers periodic and random variations of orbital and non-linear dynamical origin. The characterization of the evolution of the two-wind interaction region is necessary to understand the non-thermal emission from radio to gamma rays. For the first time, we simulate in 3D the interaction of isotropic stellar and relativistic pulsar winds along one full orbit, on scales well beyond the binary size. We also investigate the impact of grid resolution and size. We carry out, with the code PLUTO, relativistic hydrodynamical simulations in 2 and 3D of the interaction of a slow dense wind and a mildly relativistic wind along one full orbit, up to ~100 times the binary size. The 2-dimensional simulations are carried out with equal and larger grid resolution and size than in 3D. The simulations in 3D confirm previous results in 2D, showing a strong shock induced by Coriolis forces that terminates the pulsar wind in ...

  8. Novel patterns of cancer genome evolution

    Institute of Scientific and Technical Information of China (English)

    Xia Zhang; Xiaodi Deng; Yu Zhang; Zhiguang Li

    2015-01-01

    Cells usually undergo a long journey of evolution during the progression from normal to precancerous cells and finally to full-fledged cancer cells. Multiple genomic aberrations are acquired during this journey that could either act as drivers to confer significant growth advantages or act as passengers with little effect on the tumor growth. Recent advances in sequencing technology have made it feasible to decipher the evolutionary course of a cancer cell on a genome-wide level by evaluating the relative number of mutated alleles. Novel terms such as chromothripsis and chromoplexy have been introduced to describe the newly identified patterns of cancer genome evolution. These new insights have greatly expanded our understanding of the initiation and progression of cancers, which should aid in improving the efficiency of cancer management and treatment.

  9. Warm ionized gas in CALIFA early-type galaxies. 2D emission-line patterns and kinematics for 32 galaxies

    Science.gov (United States)

    Gomes, J. M.; Papaderos, P.; Kehrig, C.; Vílchez, J. M.; Lehnert, M. D.; Sánchez, S. F.; Ziegler, B.; Breda, I.; Dos Reis, S. N.; Iglesias-Páramo, J.; Bland-Hawthorn, J.; Galbany, L.; Bomans, D. J.; Rosales-Ortega, F. F.; Cid Fernandes, R.; Walcher, C. J.; Falcón-Barroso, J.; García-Benito, R.; Márquez, I.; Del Olmo, A.; Masegosa, J.; Mollá, M.; Marino, R. A.; González Delgado, R. M.; López-Sánchez, Á. R.; Califa Collaboration

    2016-04-01

    traces of localized star formation in the extranuclear component of several of our sample galaxies points to a non-negligible contribution by OB stars to the global ionizing photon budget in ETGs. Additionally, our data again highlight the diversity of ETGs in their gaseous and stellar kinematics. While in one half of our sample, gas and stars show similar (yet not necessarily identical) velocity patterns that are both dominated by rotation along the major galaxy axis, our analysis also documents several cases of kinematical decoupling between gas and stars, or rotation along the minor galaxy axis. We point out that the generally very low (≲1 Å) EW(Hα) of ETGs requires a careful quantitative assessment of potential observational and analysis biases in studies of their wim. With standard emission-line fitting tools, Balmer emission lines become progressively difficult to detect below an EW(Hα) ~ 3 Å, therefore our current understanding of the presence and 2D emission patterns and kinematics of the diffuse wim ETGs may be severely incomplete. We demonstrate that at the typical emission-line detection threshold of ~2 Å in previous studies, most of the extranuclear wim emission in an ETG may evade detection, which could in turn cause ETGs to be classified as entirely gas-devoid systems. Conclusions: This study adds further observational evidence for a considerable heterogeneity among ETGs with regard to the physical properties and 2D kinematics of their extended wim component, and it clearly shows that a comprehensive understanding of these systems requires IFS studies over their entire optical extent.

  10. The Evolution of Trilobite Body Patterning

    Science.gov (United States)

    Hughes, Nigel C.

    2007-05-01

    The good fossil record of trilobite exoskeletal anatomy and ontogeny, coupled with information on their nonbiomineralized tissues, permits analysis of how the trilobite body was organized and developed, and the various evolutionary modifications of such patterning within the group. In several respects trilobite development and form appears comparable with that which may have characterized the ancestor of most or all euarthropods, giving studies of trilobite body organization special relevance in the light of recent advances in the understanding of arthropod evolution and development. The Cambrian diversification of trilobites displayed modifications in the patterning of the trunk region comparable with those seen among the closest relatives of Trilobita. In contrast, the Ordovician diversification of trilobites, although contributing greatly to the overall diversity within the clade, did so within a narrower range of trunk conditions. Trilobite evolution is consistent with an increased premium on effective enrollment and protective strategies, and with an evolutionary trade-off between the flexibility to vary the number of trunk segments and the ability to regionalize portions of the trunk.

  11. Moving-Particle Semi-Implicit Method for Vortex Patterns and Roll Damping of 2D Ship Sections

    Institute of Scientific and Technical Information of China (English)

    PAN Xu-jie; ZHANG Huai-xin; LU Yun-tao

    2008-01-01

    A meshless method, Moving-Particle Semi-Implicit Method (MPS) is presented in this paper to simulate the rolling of different 2D ship sections. Sections S.S.0.5, S.S.5.0 and S.S.7.0 of series 60 with CB=0.6 are chosen for the simulation. It shows that the result of MPS is very close to results of experiments or mesh-numerical simulations. In the simulation of MPS, vortices are found periodically in bilges of ship sections. In section S.S.5.0 and section S.S.7.0, which are close to the middle ship, two little vortices are found at different bilges of the section, in section S.S.0.5, which is close to the bow, only one big vortex is found at the bottom of the section, these vortices patterns are consistent with the theory of Ikeda. The distribution of shear stress and pressure on the rolling hull of ship section is calculated. When vortices are in bilges of the section, the sign change of pressure can be found, but in section S.S.0.5, there is no sign change of pressure because only one vortex in the bottom of the section. With shear stress distribution, it can be found the shear stress in bilges is bigger than that at other part of the ship section. As the free surface is considered, the shear stress of both sides near the free surface is close to zero and even sign changed.

  12. Global patterns of sequence evolution in Drosophila

    Directory of Open Access Journals (Sweden)

    Marín Ignacio

    2007-11-01

    Full Text Available Abstract Background Sequencing of the genomes of several Drosophila allows for the first precise analyses of how global sequence patterns change among multiple, closely related animal species. A basic question is whether there are characteristic features that differentiate chromosomes within a species or between different species. Results We explored the euchromatin of the chromosomes of seven Drosophila species to establish their global patterns of DNA sequence diversity. Between species, differences in the types and amounts of simple sequence repeats were found. Within each species, the autosomes have almost identical oligonucleotide profiles. However, X chromosomes and autosomes have, in all species, a qualitatively different composition. The X chromosomes are less complex than the autosomes, containing both a higher amount of simple DNA sequences and, in several cases, chromosome-specific repetitive sequences. Moreover, we show that the right arm of the X chromosome of Drosophila pseudoobscura, which evolved from an autosome 10 – 18 millions of years ago, has a composition which is identical to that of the original, left arm of the X chromosome. Conclusion The consistent differences among species, differences among X chromosomes and autosomes and the convergent evolution of X and neo-X chromosomes demonstrate that strong forces are acting on drosophilid genomes to generate peculiar chromosomal landscapes. We discuss the relationships of the patterns observed with differential recombination and mutation rates and with the process of dosage compensation.

  13. Mining Botnets and Their Evolution Patterns

    Institute of Scientific and Technical Information of China (English)

    Jaehoon Choi; Jaewoo Kang; Jinseung Lee; Chihwan Song; Qingsong Jin; Sunwon Lee; Jinsun Uh

    2013-01-01

    The botnet is the network of compromised computers that have fallen under the control of hackers after being infected by malicious programs such as trojan viruses.The compromised machines are mobilized to perform various attacks including mass spamming,distributed denial of service (DDoS) and additional trojans.This is becoming one of the most serious threats to the Internet infrastructure at present.We introduce a method to uncover compromised machines and characterize their behaviors using large email logs.We report various spam campaign variants with different characteristics and introduce a statistical method to combine them.We also report the long-term evolution patterns of the spam campaigns.

  14. Centimeter Scale Patterned Growth of Vertically Stacked Few Layer Only 2D MoS2/WS2 van der Waals Heterostructure

    Science.gov (United States)

    Choudhary, Nitin; Park, Juhong; Hwang, Jun Yeon; Chung, Hee-Suk; Dumas, Kenneth H.; Khondaker, Saiful I.; Choi, Wonbong; Jung, Yeonwoong

    2016-05-01

    Two-dimensional (2D) van der Waal (vdW) heterostructures composed of vertically-stacked multiple transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) are envisioned to present unprecedented materials properties unobtainable from any other material systems. Conventional fabrications of these hybrid materials have relied on the low-yield manual exfoliation and stacking of individual 2D TMD layers, which remain impractical for scaled-up applications. Attempts to chemically synthesize these materials have been recently pursued, which are presently limited to randomly and scarcely grown 2D layers with uncontrolled layer numbers on very small areas. Here, we report the chemical vapor deposition (CVD) growth of large-area (>2 cm2) patterned 2D vdW heterostructures composed of few layer, vertically-stacked MoS2 and WS2. Detailed structural characterizations by Raman spectroscopy and high-resolution/scanning transmission electron microscopy (HRTEM/STEM) directly evidence the structural integrity of two distinct 2D TMD layers with atomically sharp vdW heterointerfaces. Electrical transport measurements of these materials reveal diode-like behavior with clear current rectification, further confirming the formation of high-quality heterointerfaces. The intrinsic scalability and controllability of the CVD method presented in this study opens up a wide range of opportunities for emerging applications based on the unconventional functionalities of these uniquely structured materials.

  15. Evolution of sexual dimorphism in the digit ratio 2D:4D--relationships with body size and microhabitat use in iguanian lizards.

    Directory of Open Access Journals (Sweden)

    Camilla M Gomes

    Full Text Available The ratio between lengths of digit II and IV (digit ratio 2D:4D is a morphological feature that likely affects tetrapod locomotor performances in different microhabitats. Modifications of this trait may be triggered by changes in steroids concentrations during embryo development, which might reflect direct selection acting on digit ratio or be solely a consequence of hormonal differences related for example to body size. Here we apply both conventional and phylogenetic analyses on morphological data from 25 lizard species of 3 families of Iguania (Iguanidae, Polychrotidae, and Tropiduridae, in order to verify whether selective pressures related to locomotion in different microhabitats could override the prenatal developmental cues imposed on the digit ratio 2D:4D by differences in body size between males and females. Data suggest that this trait evolved in association with ecological divergence in the species studied, despite the clear effect of body size on the digit ratio 2D:4D. The ecological associations of size-corrected digit ratios were restricted to one sex, and females of species that often use perches exhibited small digit ratios in the front limbs, which translated into larger sexual dimorphism indexes of arboreal species. The results, together with the subsequent discussion, provide outlines for further investigation about possible developmental mechanisms related to the evolution of adaptive changes in digit lengths that may have occurred during the evolution of ecological divergence in squamates.

  16. PSEMA: An Algorithm for Pattern Stimulated Evolution of Music

    Science.gov (United States)

    Mavrogianni, A. N.; Vlachos, D. S.; Harvalias, G.

    2008-11-01

    An algorithm for pattern stimulating evolution of music is presented in this work (PSEMA). The system combines a pattern with a genetic algorithm for automatic music composition in order to create a musical phrase uniquely characterizing the pattern. As an example a musical portrait is presented. The initialization of the musical phrases is done with a Markov Chain process. The evolution is dominated by an arbitrary correspondence between the pattern (feature extraction of the pattern may be used in this step) and the esthetic result of the musical phrase.

  17. A numerical investigation of the evolution of 2-D disturbances in hypersonic boundary layers and the effect on the flow structure due to the existence of shocklets

    Institute of Scientific and Technical Information of China (English)

    CAO; Wei; ZHOU; Heng

    2004-01-01

    The evolution of 2-D disturbances in hypersonic boundary layer with Mach number 6,8, and 10 was investigated numerically by three different numerical schemes.At the entrance, second mode T-S waves with different amplitudes were introduced, and the relation between the Mach number and the amplitude of the disturbance when shocklets started to appear was investigated. By comparing the disturbance velocity profiles with those provided by linear stability theory, the effects of shocklets on flow structures were also investigated.

  18. Exploring the evolution of investment pattern on advanced manufacturing technology

    DEFF Research Database (Denmark)

    Yang, Cheng; Matthiesen, Rikke Vestergaard; Johansen, John

    2014-01-01

    This paper explores the evolution of investment pattern on advanced manufacturing technology in a manner that builds on a longitudinal perspective. Based on the data of investments in AMTs from 567 manufacturing companies this paper develops a longitudinal taxonomy defined by the evolution...

  19. A coupled 2$\\times$2D Babcock-Leighton solar dynamo model. I. Surface magnetic flux evolution

    CERN Document Server

    Lemerle, Alexandre; Carignan-Dugas, Arnaud

    2015-01-01

    The need for reliable predictions of the solar activity cycle motivates the development of dynamo models incorporating a representation of surface processes sufficiently detailed to allow assimilation of magnetographic data. In this series of papers we present one such dynamo model, and document its behavior and properties. This first paper focuses on one of the model's key components, namely surface magnetic flux evolution. Using a genetic algorithm, we obtain best-fit parameters of the transport model by least-squares minimization of the differences between the associated synthetic synoptic magnetogram and real magnetographic data for activity cycle 21. Our fitting procedure also returns Monte Carlo-like error estimates. We show that the range of acceptable surface meridional flow profiles is in good agreement with Doppler measurements, even though the latter are not used in the fitting process. Using a synthetic database of bipolar magnetic region (BMR) emergences reproducing the statistical properties of ...

  20. EVOLUTIVE PATTERN FOR THE ECONOMIC GLOBALIZATION

    Directory of Open Access Journals (Sweden)

    SILVIU-MARIUS ŞEITAN

    2014-06-01

    Full Text Available The necessity to identify and implement a solution for the region subject to the process globalization appeared due to the following reasons: during the stage of evolution of the process of globalization, there is no kind of coordination of this process towards the accomplishment of its goals, the character of this process being determined by the multitude of microeconomic processual elements coordinated from particular levels; therefore, the only objectives to be achieved are microeconomic by their nature, and there is a risk that adverse effects appear at the macroeconomic levels in relation with the specific objectives of the microeconomic level; the possible configuration of a global system of process administration is outrun temporally by the evolution of the global real economy. This entire period, represented by the stage of evolution of the process of globalization, is characterized by the lack of risk management capacity, the only such capacities, possibly to be activated, being those at the local level, but they have a low efficacy compared to the global nature of the risk and effects.

  1. Characteristics of surface plasmon-polariton waves excited on 2D periodically patterned columnar thin films of silver.

    Science.gov (United States)

    Dutta, Jhuma; Anantha Ramakrishna, S; Lakhtakia, Akhlesh

    2016-09-01

    Periodically patterned thin films of slanted silver nanocolumns were deposited by directing a collimated vapor flux of silver toward square and hexagonal gratings of photoresist on glass substrates. Angle-resolved specular-transmittance measurements in the visible and near-infrared wavelength bands on these periodically patterned columnar thin films (CTFs) were carried out to investigate the excitation of surface plasmon-polariton (SPP) waves bound tightly to either the air/CTF or the photoresist/CTF interfaces. The orientation of the propagation vector of the incident p-polarized plane wave with respect to the morphologically significant plane of the CTFs was varied to reveal asymmetric (unidirectional) coupling of Floquet modes to SPP waves. The asymmetric coupling is maximal when the propagation vector of the incident plane wave lies wholly in the morphologically significant plane. Theoretical understanding based on the Bruggeman formalism to homogenize the silver CTFs into hyperbolic biaxial continua is able to explain the experimental observations very well. PMID:27607490

  2. Molecular phylogenetics in 2D: ITS2 rRNA evolution and sequence-structure barcode from Veneridae to Bivalvia.

    Science.gov (United States)

    Salvi, Daniele; Mariottini, Paolo

    2012-11-01

    In this study, we analyzed the nuclear ITS2 rRNA primary sequence and secondary structure in Veneridae and comparatively with 20 Bivalvia taxa to test the phylogenetic resolution of this marker and its suitability for molecular diagnosis at different taxonomic levels. Maximum likelihood and Bayesian trees based on primary sequences were congruent with (profile-) neighbor-joining trees based on a combined model of sequence-structure evolution. ITS2 showed higher resolution below the subfamily level, providing a phylogenetic signal comparable to (mitochondrial/nuclear) gene fragments 2-5 times longer. Structural elements of the ITS2 folding, such as specific mismatch pairing and compensatory base changes, provided further support for the monophyly of some groups and for their phylogenetic relationships. Veneridae ITS2 folding is structured in six domains (DI-VI) and shows five striking sequence-structure features. Two of them, the Basal and Apical STEMs, are common to Bivalvia, while the presence of both the Branched STEM and the Y/R stretches occurs in five superfamilies of the two Heterodonta orders Myoida and Veneroida, thus questioning their reciprocal monophyly. Our results validated the ITS2 as a suitable marker for venerids phylogenetics and taxonomy, and underlined the significance of including secondary structure information for both applications at several systematic levels within bivalves.

  3. The evolution of host mass and black hole mass in QSOs from the 2dF QSO Redshift Survey

    CERN Document Server

    Fine, S; Miller, L; Babic, A; Moore, D; Brewer, B; Sharp, R G; Boyle, B J; Shanks, T; Smith, R J; Outram, P J; Loaring, N S

    2006-01-01

    We investigate the relation between the mass of super-massive black holes (Mbh) in QSOs and the mass of the dark matter halos hosting them (Mdh). We measure the widths of broad emission lines (Mgii lambda 2798, Civ lambda 1549) from QSO composite spectra as a function of redshift. These widths are then used to determine virial black hole mass estimates. We compare our virial black hole mass estimates to dark matter halo masses for QSO hosts derived by Croom et al. (2005) based on measurements of QSO clustering. This enables us to trace the Mbh-Mdh relation over the redshift range z=0.5 to 2.5. We calculate the mean zero-point of the Mbh-Mdh relation to be Mbh=10^(8.4+/-0.2)Msun for an Mdh=10^(12.5)Msun. These data are then compared with several models connecting Mbh and Mdh as well as recent hydrodynamical simulations of galaxy evolution. We note that the flux limited nature of QSO samples can cause a Malmquist-type bias in the measured zero-point of the Mbh-Mdh relation. The magnitude of this bias depends on...

  4. Plasmonic spectrum on 1D and 2D periodic arrays of rod-shape metal nanoparticle pairs with different core patterns for biosensor and solar cell applications

    Science.gov (United States)

    Kumara, N. T. R. N.; Chou Chau, Yuan-Fong; Huang, Jin-Wei; Huang, Hung Ji; Lin, Chun-Ting; Chiang, Hai-Pang

    2016-11-01

    Simulations of surface plasmon resonance (SPR) on the near field intensity and absorption spectra of one-dimensional (1D) and two-dimensional (2D) periodic arrays of rod-shape metal nanoparticle (MNP) pairs using the finite element method (FEM) and taking into account the different core patterns for biosensor and solar cell applications are investigated. A tunable optical spectrum corresponding to the transverse SPR modes is observed. The peak resonance wavelength (λ res) can be shifted to red as the core patterns in rod-shape MNPs have been changed. We find that the 2D periodic array of core–shell MNP pairs (case 2) exhibit a red shifted SPR that can be tuned the gap enhancement and absorption efficiency simultaneously over an extended wavelength range. The tunable optical performances give us a qualitative idea of the geometrical properties of the periodic array of rod-shape MNP pairs on SPRs that can be as a promising candidate for plasmonic biosensor and solar cell applications.

  5. Influence of anisotropic grain boundary properties on the evolution of grain boundary character distribution during grain growth—a 2D level set study

    International Nuclear Information System (INIS)

    The present study elaborates on a 2D level set model of polycrystal microstructures that was recently established by adding the influence of anisotropic grain boundary energy and mobility on microstructure evolution. The new model is used to trace the evolution of grain boundary character distribution during grain growth. The employed level set formulation conveniently allows the grain boundary characteristics to be quantified in terms of coincidence site lattice (CSL) type per unit of grain boundary length, providing a measure of the distribution of such boundaries. In the model, both the mobility and energy of the grain boundaries are allowed to vary with misorientation. In addition, the influence of initial polycrystal texture is studied by comparing results obtained from a polycrystal with random initial texture against results from a polycrystal that initially has a cube texture. It is shown that the proposed level set formulation can readily incorporate anisotropic grain boundary properties and the simulation results further show that anisotropic grain boundary properties only have a minor influence on the evolution of CSL boundary distribution during grain growth. As anisotropic boundary properties are considered, the most prominent changes in the CSL distributions are an increase of general low-angle Σ1 boundaries as well as a more stable presence of Σ3 boundaries. The observations also hold for the case of an initially cube-textured polycrystal. The presence of this kind of texture has little influence over the evolution of the CSL distribution. Taking into consideration the anisotropy of grain boundary properties, grain growth alone does not seem to be sufficient to promote any significantly increased overall presence of CSL boundaries. (paper)

  6. Bar pattern speed evolution over the last 7 Gyr

    Science.gov (United States)

    Pérez, I.; Aguerri, J. A. L.; Méndez-Abreu, J.

    2012-04-01

    Context. The tumbling pattern of a bar is the main parameter characterising its dynamics. From numerical simulations, its evolution since bar formation is tightly linked to the dark halo in which the bar is formed through dynamical friction and angular momentum exchange. Observational measurements of the bar pattern speed with redshift can restrict models of galaxy formation and bar evolution. Aims: We aim to determine for the first time the bar pattern speed evolution with redshift based on morphological measurements. Methods: We have selected a sample of 44 low-inclination ringed galaxies from the SDSS and COSMOS surveys covering the redshift range 0 electronic form at http://www.aanda.orgBased on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555.

  7. Pattern evolution during ion beam sputtering; reductionistic view

    Science.gov (United States)

    Kim, J.-H.; Kim, J.-S.

    2016-09-01

    The development of the ripple pattern during the ion beam sputtering (IBS) is expounded via the evolution of its constituent ripples. For that purpose, we perform numerical simulation of the ripple evolution that is based on Bradley-Harper model and its non-linear extension. The ripples are found to evolve via various well-defined processes such as ripening, averaging, bifurcation and their combinations, depending on their neighboring ripples. Those information on the growth kinetics of each ripple allow the detailed description of the pattern development in real space that the instability argument and the diffraction study both made in k-space cannot provide.

  8. Spectral feature extraction of EEG signals and pattern recognition during mental tasks of 2-D cursor movements for BCI using SVM and ANN.

    Science.gov (United States)

    Bascil, M Serdar; Tesneli, Ahmet Y; Temurtas, Feyzullah

    2016-09-01

    Brain computer interface (BCI) is a new communication way between man and machine. It identifies mental task patterns stored in electroencephalogram (EEG). So, it extracts brain electrical activities recorded by EEG and transforms them machine control commands. The main goal of BCI is to make available assistive environmental devices for paralyzed people such as computers and makes their life easier. This study deals with feature extraction and mental task pattern recognition on 2-D cursor control from EEG as offline analysis approach. The hemispherical power density changes are computed and compared on alpha-beta frequency bands with only mental imagination of cursor movements. First of all, power spectral density (PSD) features of EEG signals are extracted and high dimensional data reduced by principle component analysis (PCA) and independent component analysis (ICA) which are statistical algorithms. In the last stage, all features are classified with two types of support vector machine (SVM) which are linear and least squares (LS-SVM) and three different artificial neural network (ANN) structures which are learning vector quantization (LVQ), multilayer neural network (MLNN) and probabilistic neural network (PNN) and mental task patterns are successfully identified via k-fold cross validation technique. PMID:27376723

  9. Sample Optimization and Identification of Signal Patterns of Amino Acid Side Chains in 2D RFDR Spectra of the α-Spectrin SH3 Domain

    Science.gov (United States)

    Pauli, Jutta; van Rossum, Barth; Förster, Hans; de Groot, Huub J. M.; Oschkinat, Hartmut

    2000-04-01

    Future structural investigations of proteins by solid-state CPMAS NMR will rely on uniformly labeled protein samples showing spectra with an excellent resolution. NMR samples of the solid α-spectrin SH3 domain were generated in four different ways, and their 13C CPMAS spectra were compared. The spectrum of a [u-13C, 15N]-labeled sample generated by precipitation shows very narrow 13C signals and resolved scalar carbon-carbon couplings. Linewidths of 16-19 Hz were found for the three alanine Cβ signals of a selectively labeled [70% 3-13C]alanine-enriched SH3 sample. The signal pattern of the isoleucine, of all prolines, valines, alanines, and serines, and of three of the four threonines were identified in 2D 13C-13C RFDR spectra of the [u-13C,15N]-labeled SH3 sample. A comparison of the 13C chemical shifts of the found signal patterns with the 13C assignment obtained in solution shows an intriguing match.

  10. Evolution of central pattern generators and rhythmic behaviours.

    Science.gov (United States)

    Katz, Paul S

    2016-01-01

    Comparisons of rhythmic movements and the central pattern generators (CPGs) that control them uncover principles about the evolution of behaviour and neural circuits. Over the course of evolutionary history, gradual evolution of behaviours and their neural circuitry within any lineage of animals has been a predominant occurrence. Small changes in gene regulation can lead to divergence of circuit organization and corresponding changes in behaviour. However, some behavioural divergence has resulted from large-scale rewiring of the neural network. Divergence of CPG circuits has also occurred without a corresponding change in behaviour. When analogous rhythmic behaviours have evolved independently, it has generally been with different neural mechanisms. Repeated evolution of particular rhythmic behaviours has occurred within some lineages due to parallel evolution or latent CPGs. Particular motor pattern generating mechanisms have also evolved independently in separate lineages. The evolution of CPGs and rhythmic behaviours shows that although most behaviours and neural circuits are highly conserved, the nature of the behaviour does not dictate the neural mechanism and that the presence of homologous neural components does not determine the behaviour. This suggests that although behaviour is generated by neural circuits, natural selection can act separately on these two levels of biological organization.

  11. Theory and realization of a 2D high resolution and high sensitivity SPECT system with an angle-encoding attenuator pattern

    Science.gov (United States)

    Feng, Tao; Wang, Jizhe; Tsui, Benjamin M. W.

    2016-04-01

    The camera of the conventional SPECT system requires a collimator to allow incoming photons from a specific range of incident angle to reach the detector. It is the major factor that determines the spatial resolution of the camera. Moreover, it also greatly reduces the number of detected photons and hence increases statistical fluctuations in the acquired image data. The goal of this paper is to propose a theory and design for a novel high resolution and high sensitivity SPECT system without conventional collimators. The key is to resolve the incident photons from all directional angles and detected by every detector bin. Special ‘attenuators’ were designed to ‘encode’ the incoming photons from different directions similar to coded aperture to form projection data for image reconstruction. Each encoded angular pattern of detected photons was recorded as one measurement. Different angular patterns were achieved by changing the configurations of the attenuators so that angular pattern of different measurements or measurement matrix (MM) is invertible, which guarantee a unique reconstructed image. In simulation, the attenuators were fitted on a virtual full-ring gamma camera, as an alternative to the collimators in conventional SPECT systems. To evaluate the performance of the new SPECT system, analytical simulated projection data in 2D scenario were generated from the XCAT phantom. Noisy simulation using 100 noise realizations suggests that the new attenuator design provides much improved image quality in terms of contrast-noise trade-offs (~30% improvement). The results suggest that the new design of using attenuators to replace collimator is feasible and could potentially improve sensitivity without sacrificing resolution in today’s SPECT systems.

  12. Instabilities and pattern evolution in a vertically heated annulus

    Science.gov (United States)

    Wang, BoFu; Guo, ZhiWei; Ma, DongJun; Sun, DeJun

    2013-02-01

    The convection in an annular container with heated bottom, cooled top and insulated side walls are studied by both linear instability analysis and direct numerical simulation. The onset of convection is investigated by linear stability analysis and corresponding pattern selection mechanisms are discussed. The nonlinear evolution of different flow patterns and the convective heat transfer are simulated. The transition to oscillatory flow is also given by stability analysis where the base flow is a steady three dimensional flow. The stability predictions are in good agreement with the numerical simulations, including both the growth rate and the dimensionless frequency.

  13. Evolution and convergence of the patterns of international scientific collaboration.

    Science.gov (United States)

    Coccia, Mario; Wang, Lili

    2016-02-23

    International research collaboration plays an important role in the social construction and evolution of science. Studies of science increasingly analyze international collaboration across multiple organizations for its impetus in improving research quality, advancing efficiency of the scientific production, and fostering breakthroughs in a shorter time. However, long-run patterns of international research collaboration across scientific fields and their structural changes over time are hardly known. Here we show the convergence of international scientific collaboration across research fields over time. Our study uses a dataset by the National Science Foundation and computes the fraction of papers that have international institutional coauthorships for various fields of science. We compare our results with pioneering studies carried out in the 1970s and 1990s by applying a standardization method that transforms all fractions of internationally coauthored papers into a comparable framework. We find, over 1973-2012, that the evolution of collaboration patterns across scientific disciplines seems to generate a convergence between applied and basic sciences. We also show that the general architecture of international scientific collaboration, based on the ranking of fractions of international coauthorships for different scientific fields per year, has tended to be unchanged over time, at least until now. Overall, this study shows, to our knowledge for the first time, the evolution of the patterns of international scientific collaboration starting from initial results described by literature in the 1970s and 1990s. We find a convergence of these long-run collaboration patterns between the applied and basic sciences. This convergence might be one of contributing factors that supports the evolution of modern scientific fields.

  14. Evolution of crustal stress, pressure and temperature around shear zones during orogenic wedge formation: a 2D thermo-mechanical numerical study

    Science.gov (United States)

    Markus Schmalholz, Stefan; Jaquet, Yoann

    2016-04-01

    We study the formation of an orogenic wedge during lithospheric shortening with 2D numerical simulations. We consider a viscoelastoplastic rheology, thermo-mechanical coupling by shear heating and temperature-dependent viscosities, gravity and erosion. In the initial model configuration there is either a lateral temperature variation at the model base or a lateral variation in crustal thickness to generate slight stress variations during lithospheric shortening. These stress variations can trigger the formation of shear zones which are caused by thermal softening associated with shear heating. We do not apply any kind of strain softening, such as reduction of friction angle with progressive plastic strain. The first major shear zone that appears during shortening crosscuts the entire crust and initiates the asymmetric subduction/underthrusting of mainly the mechanically strong lower crust. After some deformation, the first shear zone in the upper crust is abandoned, the deformation propagates towards the foreland and a new shear zone forms only in the upper crust. The shear zone propagation occurs several times where new shear zones form in the upper crust and the mechanically strong top of the lower crust acts as detachment horizon. We calculate the magnitudes of the maximal and minimal principal stresses and of the mean stress (or dynamic pressure), and we record also the temperature for several marker points in the upper and lower crust. We analyse the evolution of stresses and temperature with burial depth and time. Deviatoric stresses (half the differential stress) in the upper crust are up to 200 MPa and associated shear heating in shear zones ranges between 40 - 80 °C. Lower crustal rocks remain either at the base of the orogenic wedge at depths of around 50 km or are subducted to depths of up to 120 km, depending on their position when the first shear zone formed. Largest deviatotric stresses in the strong part of the lower crust are about 1000 MPa and

  15. Building the backbone: the development and evolution of vertebral patterning.

    Science.gov (United States)

    Fleming, Angeleen; Kishida, Marcia G; Kimmel, Charles B; Keynes, Roger J

    2015-05-15

    The segmented vertebral column comprises a repeat series of vertebrae, each consisting of two key components: the vertebral body (or centrum) and the vertebral arches. Despite being a defining feature of the vertebrates, much remains to be understood about vertebral development and evolution. Particular controversy surrounds whether vertebral component structures are homologous across vertebrates, how somite and vertebral patterning are connected, and the developmental origin of vertebral bone-mineralizing cells. Here, we assemble evidence from ichthyologists, palaeontologists and developmental biologists to consider these issues. Vertebral arch elements were present in early stem vertebrates, whereas centra arose later. We argue that centra are homologous among jawed vertebrates, and review evidence in teleosts that the notochord plays an instructive role in segmental patterning, alongside the somites, and contributes to mineralization. By clarifying the evolutionary relationship between centra and arches, and their varying modes of skeletal mineralization, we can better appreciate the detailed mechanisms that regulate and diversify vertebral patterning.

  16. Centimeter Scale Patterned Growth of Vertically Stacked Few Layer Only 2D MoS2/WS2 van der Waals Heterostructure

    OpenAIRE

    Nitin Choudhary; Juhong Park; Jun Yeon Hwang; Hee-Suk Chung; Dumas, Kenneth H.; Saiful I. Khondaker; Wonbong Choi; Yeonwoong Jung

    2016-01-01

    Two-dimensional (2D) van der Waal (vdW) heterostructures composed of vertically-stacked multiple transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2) are envisioned to present unprecedented materials properties unobtainable from any other material systems. Conventional fabrications of these hybrid materials have relied on the low-yield manual exfoliation and stacking of individual 2D TMD layers, which remain impractical for scaled-up applica...

  17. A pattern language for the evolution of component-based software architectures

    OpenAIRE

    Ahmad, Aakash; Jamshidi, Pooyan; Pahl, Claus; Khaliq, Fawad

    2014-01-01

    Architecture-centric software evolution enables change in a system’s structure and behaviour while maintaining a global view of the software to address evolution-centric trade-offs. The existing solutions for architectural maintenance and evolution fall short of exploiting generic and reusable expertise to address recurring evolution problems. We present a pattern language as a collection of interconnected change patterns that enable reuse-driven and consistent evolution of component-based so...

  18. Evolution of the shell structure in medium-mass nuclei: search for the 2d5/2 neutron orbital in 69Ni

    International Nuclear Information System (INIS)

    The harmonic oscillator shell closure at N=40 in 68Ni is weak and loses its strength when removing (or adding) pair of protons. Calculations performed in this mass region predict a new island of inversion at N=40 similar to the one at N=20. Using a large valence space, the neutron orbital 2d(5/2) is shown to be a crucial ingredient for the interpretation of the nuclear structure at N ∼40. The neutron 1g(9/2) -2d(5/2) energy difference has been determined in 69Ni beam at 25.14 MeV/u separated by the LISE3 spectrometer was impinging a CD2 target of 2.6 mg/cm2 thickness. The experimental setup consisted of CATS/MUST2-S1/EXOGAM detectors coupled to an ionization chamber and a plastic scintillator. The angular moment and spectroscopic factors of the ground state (Jπ=9/2+) and a doublet of states (Jπ=5/2+) around 2.48 MeV corresponding to the population of the 1g(9/2) and the 2d(5/2) orbitals, were obtained from the comparison between the experimental cross-sections as a function of the proton detection angle and ADWA calculations. The spins of the observed states were assigned by comparison to large scale Shell-Model calculations. The position of the 2d(5/2) orbital in 69Ni has been established for the first time. Our measurements support the hypothesis of a low-lying 2d(5/2) orbital (∼2.5 MeV) with respect to the 1g(9/2) neutron orbital and thus its major role in the structure of the nuclei around N=40. (author)

  19. Evolution of differentiated expression patterns in digital organisms

    CERN Document Server

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

    2000-01-01

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

  20. Herbivorous ecomorphology and specialization patterns in theropod dinosaur evolution.

    Science.gov (United States)

    Zanno, Lindsay E; Makovicky, Peter J

    2011-01-01

    Interpreting key ecological parameters, such as diet, of extinct organisms without the benefit of direct observation or explicit fossil evidence poses a formidable challenge for paleobiological studies. To date, dietary categorizations of extinct taxa are largely generated by means of modern analogs; however, for many species the method is subject to considerable ambiguity. Here we present a refined approach for assessing trophic habits in fossil taxa and apply the method to coelurosaurian dinosaurs--a clade for which diet is particularly controversial. Our findings detect 21 morphological features that exhibit statistically significant correlations with extrinsic fossil evidence of coelurosaurian herbivory, such as stomach contents and a gastric mill. These traits represent quantitative, extrinsically founded proxies for identifying herbivorous ecomorphology in fossils and are robust despite uncertainty in phylogenetic relationships among major coelurosaurian subclades. The distribution of these features suggests that herbivory was widespread among coelurosaurians, with six major subclades displaying morphological evidence of the diet, and that contrary to previous thought, hypercarnivory was relatively rare and potentially secondarily derived. Given the potential for repeated, independent evolution of herbivory in Coelurosauria, we also test for repetitive patterns in the appearance of herbivorous traits within sublineages using rank concordance analysis. We find evidence for a common succession of increasing specialization to herbivory in the subclades Ornithomimosauria and Oviraptorosauria, perhaps underlain by intrinsic functional and/or developmental constraints, as well as evidence indicating that the early evolution of a beak in coelurosaurians correlates with an herbivorous diet. PMID:21173263

  1. Overlapping patterns of brain activation to food and cocaine cues in cocaine abusers: association to striatal D2/D3 receptors

    OpenAIRE

    Tomasi, Dardo; Wang, Gene-Jack; Wang, Ruiliang; Caparelli, Elisabeth C.; Logan, Jean; Volkow, Nora D.

    2014-01-01

    Cocaine, through its activation of dopamine (DA) signaling, usurps pathways that process natural rewards. However, the extent to which there is overlap between the networks that process natural and drug rewards and whether DA signaling associated with cocaine abuse influences these networks have not been investigated in humans. We measured brain activation responses to food and cocaine cues with fMRI, and D2/D3 receptors in the striatum with [11C]raclopride and PET in 20 active cocaine abuser...

  2. Overlapping patterns of brain activation to food and cocaine cues in cocaine abusers: association to striatal D2/D3 receptors.

    Science.gov (United States)

    Tomasi, Dardo; Wang, Gene-Jack; Wang, Ruiliang; Caparelli, Elisabeth C; Logan, Jean; Volkow, Nora D

    2015-01-01

    Cocaine, through its activation of dopamine (DA) signaling, usurps pathways that process natural rewards. However, the extent to which there is overlap between the networks that process natural and drug rewards and whether DA signaling associated with cocaine abuse influences these networks have not been investigated in humans. We measured brain activation responses to food and cocaine cues with fMRI, and D2/D3 receptors in the striatum with [11C]raclopride and Positron emission tomography in 20 active cocaine abusers. Compared to neutral cues, food and cocaine cues increasingly engaged cerebellum, orbitofrontal, inferior frontal, and premotor cortices and insula and disengaged cuneus and default mode network (DMN). These fMRI signals were proportional to striatal D2/D3 receptors. Surprisingly cocaine and food cues also deactivated ventral striatum and hypothalamus. Compared to food cues, cocaine cues produced lower activation in insula and postcentral gyrus, and less deactivation in hypothalamus and DMN regions. Activation in cortical regions and cerebellum increased in proportion to the valence of the cues, and activation to food cues in somatosensory and orbitofrontal cortices also increased in proportion to body mass. Longer exposure to cocaine was associated with lower activation to both cues in occipital cortex and cerebellum, which could reflect the decreases in D2/D3 receptors associated with chronicity. These findings show that cocaine cues activate similar, though not identical, pathways to those activated by food cues and that striatal D2/D3 receptors modulate these responses, suggesting that chronic cocaine exposure might influence brain sensitivity not just to drugs but also to food cues. PMID:25142207

  3. A simple model for research interest evolution patterns

    Science.gov (United States)

    Jia, Tao; Wang, Dashun; Szymanski, Boleslaw

    Sir Isaac Newton supposedly remarked that in his scientific career he was like ``...a boy playing on the sea-shore ...finding a smoother pebble or a prettier shell than ordinary''. His remarkable modesty and famous understatement motivate us to seek regularities in how scientists shift their research focus as the career develops. Indeed, despite intensive investigations on how microscopic factors, such as incentives and risks, would influence a scientist's choice of research agenda, little is known on the macroscopic patterns in the research interest change undertaken by individual scientists throughout their careers. Here we make use of over 14,000 authors' publication records in physics. By quantifying statistical characteristics in the interest evolution, we model scientific research as a random walk, which reproduces patterns in individuals' careers observed empirically. Despite myriad of factors that shape and influence individual choices of research subjects, we identified regularities in this dynamical process that are well captured by a simple statistical model. The results advance our understanding of scientists' behaviors during their careers and open up avenues for future studies in the science of science.

  4. Using Divergent Δ12CH2D2 and Δ13CH3D to Trace the Provenance and Evolution of Methane Gas

    Science.gov (United States)

    Young, E. D.; Freedman, P.; Mills, M.; Rumble, D.

    2015-12-01

    Measurements of Δ13CH3D (deviations in Δ13CH3D/12CH4 from stochastic; Ono et al. Anal. Chem. v.86, p.6487, 2014) or Δ18 (from (12CH2D2 + 13CH3D)/12CH4; Stolper et al. Science, v.344, p.1500, 2014, ) have been used to infer temperatures of formation of methane gas. However, departures from thermodynamic equilibrium isotopic bond ordering will result from any fractionating process that do not include bond rupture and reformation, including mixing, diffusion, and kinetic processing. This is because the isotopic bond ordering no longer reflects the bulk isotopic composition once fractionation occurs. A direct measure of departures from thermodynamic equilibrium isotopic bond ordering in methane comes from both Δ12CH2D2 and Δ13CH3D in the same gas. Until now, this has not been possible due to instrumental limitations. We have carried out measurements of Δ12CH2D2 and Δ13CH3D in methane gas mixtures using a unique, large-geometry double-focusing isotope ratio mass spectrometer (IRMS), the Panorama, in order to investigate the usefulness of these two mass-18 isotopologues as tracers of mixing of methane sources. This instrument has a dispersion/magnification ratio, the parameter of merit for mass resolving power, of ~ 1400 mm that exceeds that of any other gas-source IRMS by more than 3.5x and is slightly larger than that for large-geometry SIMS instruments. With this geometry we routinely operate with mass resolving power (M/ΔM, 5% and 95%) of 40,000 or greater with useful sensitivity for isotope ratio analysis. For these experiments we mixed two gases with bulk D/H differing by 100 ‰. The results follow theoretical expectations within uncertainties of 0.5 ‰ for Δ12CH2D2 and 0.1 ‰ for Δ13CH3D. Precision is sufficient to detect as little as 10% mixing in this system. This precision would also be capable of detecting subtle departures from equilibrium caused by diffusion and kinetic bond rupture (e.g. CH4 + OH).

  5. Evolution of anthropoid jaw loading and kinematic patterns.

    Science.gov (United States)

    Ravosa, M J; Vinyard, C J; Gagnon, M; Islam, S A

    2000-08-01

    Major transformations in the skull and masticatory system characterized the evolution of crown anthropoids. To offer further insight into the phylogenetic and arguably adaptive significance of specific primate mandibular loading and kinematic patterns, allometric analyses of metric parameters linked to masticatory function are performed within and between 47 strepsirhine and 45 recent anthropoid species. When possible, basal anthropoids are considered. These results are subsequently integrated with prior experimental and morphological work on primate skull form. As compared to strepsirhines, crown anthropoids have a vertically longer ascending ramus linked to a glenoid and condyle positioned relatively higher above the occlusal plane. Interestingly, anthropoids and strepsirhines do not exhibit different mean ratios of condylar to glenoid height, which suggests that both clades are similar in their ability to evenly distribute occlusal contacts and perhaps forces along the postcanine teeth. Thus, given the considerable suborder differences in the scaling of both glenoid and condylar height, we argue that much of this variation in jaw-joint height is linked to suborder differences in relative facial height due in turn to increased encephalization, basicranial flexion, and facial kyphosis in anthropoids. Due to a more elongate ascending ramus, anthropoids evince more vertically oriented masseters than like-sized strepsirhines. Having a relatively longer ramus and a more medially displaced lateral pterygoid plate, crown anthropoids exhibit medial pterygoids oriented similar to those of strepsirhines, but with a variably longer lever arm. As anthropoid masseters are less advantageously placed to effect transverse movements/forces, we argue that balancing-side deep-masseter activity underlying a wishboning loading regime serves to increase, or at least maintain, transverse levels of jaw movement and occlusal force at the end of the masticatory power stroke. Crown

  6. The evolution of host mass and black hole mass in quasi-stellar objects from the 2dF QSO Redshift Survey

    Science.gov (United States)

    Fine, S.; Croom, S. M.; Miller, L.; Babic, A.; Moore, D.; Brewer, B.; Sharp, R. G.; Boyle, B. J.; Shanks, T.; Smith, R. J.; Outram, P. J.; Loaring, N. S.

    2006-12-01

    We investigate the relation between the mass of supermassive black holes (MBH) in quasi-stellar objects (QSOs) and the mass of the dark matter haloes hosting them (MDH). We measure the widths of broad emission lines (MgII λ2798, CIV λ1549) from QSO composite spectra as a function of redshift. These widths are then used to determine virial black hole mass estimates. We compare our virial black hole mass estimates to dark matter halo masses for QSO hosts derived by Croom et al. based on measurements of QSO clustering. This enables us to trace the MBH-MDH relation over the redshift range z = 0.5-2.5. We calculate the mean zero-point of the MBH-MDH relation to be MBH = 108.4+/-0.2Msolar for an MDH = 1012.5Msolar. These data are then compared with several models connecting MBH and MDH as well as recent hydrodynamical simulations of galaxy evolution. We note that the flux-limited nature of QSO samples can cause a Malmquist-type bias in the measured zero-point of the MBH-MDH relation. The magnitude of this bias depends on the scatter in the MBH-MDH relation, and we re-evaluate the zero-point assuming three published values for this scatter. We create a subsample of our data defined by a constant magnitude interval around L* and find (1 + z)3.3+/-1.3 evolution in MBH between z ~ 0.5 and 2.5 for typical, L* QSOs. We also determine the Eddington ratios (L/LEdd) for the same subsample and find no significant evolution: (1 + z)-0.4+/-1.1. Taken at face value, our data suggest that a decrease in active black hole mass since z ~ 2.5 is the driving force behind luminosity evolution of typical, L*, optically selected QSOs. However, we note that our data are also consistent with a picture in which reductions in both black hole mass and accretion rate contribute equally to luminosity evolution. In addition, we find that these evolution results are strongly affected by the virial black hole mass estimators used. Changes to the calibration of these have a significant effect on the

  7. Calculation of the spatial distribution of photovoltaic field by arbitrary 2D ilumination patterns en LiNbO3; application to photovoltaic particle trapping.

    OpenAIRE

    Arregui Hernández, Cándido; Alcazar de Velasco Rico, Angel Manuel; Ramiro Diaz, Jose Bruno; Mendez Jaque, Angel; Villarroel, J.; García Cabañes, A.; Carrascosa, M.

    2013-01-01

    Patterns of evanescent photovoltaic field induced by illumination on a surface of lithium niobate (LN) have been calculated and compared with the experimental patterns of nano- and microparticles trapped by dielectrophoretic forces. A tool for this calculation has been developed. Calculo de distribución espacial de campo por efecto fotovoltaico con patrones arbitrarios de iluminación, en LiNbO3

  8. The warm ionized gas in CALIFA early-type galaxies: 2D emission-line patterns and kinematics for 32 galaxies

    CERN Document Server

    Gomes, J M; Kehrig, C; Vílchez, J M; Lehnert, M D; Sánchez, S F; Ziegler, B; Breda, I; Reis, S N dos; Iglesias-Páramo, J; Bland-Hawthorn, J; Galbany, L; Bomans, D J; Rosales-Ortega, F F; Fernandes, R Cid; Walcher, C J; Falcón-Barroso, J; García-Benito, R; Márquez, I; del Olmo, A; Masegosa, J; Mollá, M; Marino, R A; Delgado, R M González; López-Sánchez, Á R

    2015-01-01

    The morphological, spectroscopic and kinematical properties of the warm interstellar medium (wim) in early-type galaxies (ETGs) hold key observational constraints to nuclear activity and the buildup history of these massive, quiescent systems. High-quality integral field spectroscopy (IFS) data with a wide spectral and spatial coverage, such as those from the CALIFA survey, offer an unprecedented opportunity for advancing our understanding of the wim in ETGs. This article centers on a 2D investigation of the wim component in 32 nearby (<~150Mpc) ETGs from CALIFA, complementing a previous 1D analysis of the same sample (Papaderos et al. 2013; P13). We include here H\\alpha\\ intensity and equivalent width (EW) maps and radial profiles, diagnostic emission-line ratios, besides ionized-gas and stellar kinematics. This study is supplemented by \\tau-ratio maps as an efficient means to quantify the role of photoionization by pAGB stars, as compared to other mechanisms (e.g., AGN, low-level star formation). Additio...

  9. A Pattern Language for the Evolution of Component-based Software Architectures

    DEFF Research Database (Denmark)

    Ahmad, Aakash; Jamshidi, Pooyan; Pahl, Claus;

    2013-01-01

    Modern software systems are prone to a continuous evolution under frequently varying requirements. Architecture-centric software evolution enables change in system’s structure and behavior while maintaining a global view of the software to address evolution-centric tradeoffs. Lehman’s law...... of continuing change demands for long-living and continuously evolving architectures to prolong the productive life and economic value of deployed software. However, existing solutions for architectural maintenance and evolution fall short of exploiting generic and reusable expertise to address recurring...... that enable reuse-driven and consistent evolution in component-based software architectures. Pattern interconnections represent possible relationships among patterns (such as variants or related patterns) in the language. In general, we introduce architecture change mining (pattern language development...

  10. Binary Bell Polynomials, Bilinear Approach to Exact Periodic Wave Solutions of (2 d- 1)-Dimensional Nonlinear Evolution Equations

    Institute of Scientific and Technical Information of China (English)

    王云虎; 陈勇

    2011-01-01

    In the present letter, we get the appropriate bilinear forms of (2 + 1)-dimensional KdV equation, extended (2 + 1)-dimensional shallow water wave equation and (2 + 1)-dimensional Sawada -Kotera equation in a quick and natural manner, namely by appling the binary Bell polynomials. Then the Hirota direct method and Riemann theta function are combined to construct the periodic wave solutions of the three types nonlinear evolution equations. And the corresponding figures of the periodic wave solutions are given. Furthermore, the asymptotic properties of the periodic wave solutions indicate that the soliton solutions can be derived from the periodic wave solutions.

  11. An evolution model of dislocation patterns in plastic deformation and its applications

    Institute of Scientific and Technical Information of China (English)

    高维林; 白光润; 周志敏

    1995-01-01

    By combining the classic dislocation theory with the principle of dissipative structure and synergetics, an evolution model of dislocation patterns has been developed. Using this model, the evolution of dislocation patterns and the corresponding mechanical behavior have been analyzed, discussed and simulated under different deformation conditions of constant strain rate, creep and static recovery. As one of the most essential problems in the plastic deformation, the evolution of dislocation patterns has been dealt with by using non-linear methods. Results show that various problems in plastic deformation may be solved in a unified theoretical framework.

  12. Tomographic analysis of data from the JET neutron profile monitor to deduce the 2-D spatial and temporal evolution of neutron emissivity

    International Nuclear Information System (INIS)

    Measurements from the JET neutron profile monitor are analyzed tomographically to deduce the two-dimensional spatial distribution of neutron emissivity and its temporal evolution. The most dramatic change in the emissivity profile is produced by a sawtooth crash. The profiles before and after a sawtooth crash are determined and changes in their characteristics, such as width and amplitude, are compared to those deduced from other diagnostics, including soft X-rays, electron density interferometers and electron cyclotron emission. The drop in the central neutron emissivity can be much larger than that obtained from the integrated global neutron emission, and hollow emissivity profiles are produced. The observed inversion radius is the same on neutron, soft X-ray, and electron temperature profiles. This hollow profile can be understood by observations of the soft X-ray emissivity on the fastest time-scale. A major theme of this paper is that much more information and understanding can be gained if several diagnostics are used together, with their different resolutions, time-scales and physical properties measured. (author). 12 refs, 5 figs

  13. Land use pattern evolution and optimization in the Farming-Pastoral Zone of Northern China

    Institute of Scientific and Technical Information of China (English)

    CHEN; Yunhao; SU; Wei; WU; Yongfeng; YU; Xiaomin; ZHANG; Jinshui

    2006-01-01

    Using information about the land cover of the Farming-Pastoral Zone of Northern China retrieved from multi-temporal NOAA/AVHRR and SPOT VEGETAN images obtained in 1989, 1994 and 1999, the authors analyzed land-use pattern evolution over this 10-year period and built a land-use pattern simulation model, based on which land-use pattern evolution and optimization modeling in this region were studied. Results showed that the proposed model can effectively simulate regional land-use patterns and help improve regional ecological environments.

  14. Disease transmission promotes evolution of host spatial patterns.

    Science.gov (United States)

    Irvine, Michael A; Bull, James C; Keeling, Matthew J

    2016-09-01

    Ecological dynamics can produce a variety of striking patterns. On ecological time scales, pattern formation has been hypothesized to be due to the interaction between a species and its local environment. On longer time scales, evolutionary factors must be taken into account. To examine the evolutionary robustness of spatial pattern formation, we construct a spatially explicit model of vegetation in the presence of a pathogen. Initially, we compare the dynamics for vegetation parameters that lead to competition induced spatial patterns and those that do not. Over ecological time scales, banded spatial patterns dramatically reduced the ability of the pathogen to spread, lowered its endemic density and hence increased the persistence of the vegetation. To gain an evolutionary understanding, each plant was given a heritable trait defining its resilience to competition; greater competition leads to lower vegetation density but stronger spatial patterns. When a disease is introduced, the selective pressure on the plant's resilience to the competition parameter is determined by the transmission of the disease. For high transmission, vegetation that has low resilience to competition and hence strong spatial patterning is an evolutionarily stable strategy. This demonstrates a novel mechanism by which striking spatial patterns can be maintained by disease-driven selection. PMID:27628172

  15. Patterns of technological innovation and evolution in the energy sector: A patent-based approach

    International Nuclear Information System (INIS)

    Given the ever-increasing pace and complexity of technological innovation in the energy sector, monitoring technological changes has become of strategic importance. One of the most common techniques for technology monitoring is patent analysis, which enables the identification of technological trends over time. However, few previous studies have carried out patent analysis in the energy sector. This study aims to explore patterns of innovation and of evolution in energy technologies, particularly focusing on similarities and differences across technologies. For this purpose, we first defined the relevant energy technologies and extracted the associated patent data from the United States Patents and Trademark Office (USPTO) and then adopted six patent indices and developed six patent maps to analyze their innovation characteristics. We then clustered energy technologies with similar characteristics, so defining innovation categories, and analyzed the changes in these characteristics over time to define their evolution categories. As one of the few attempts to investigate the overall trends in the energy sector's innovation and evolution, this study is expected to help develop an in-depth understanding of the energy industry, which will be useful in establishing technology strategies and policy in this rapidly changing sector. - Highlights: • We examined the patterns of innovation and evolution of energy technologies. • Six types of innovation patterns such as “competitive” or “mature” were identified. • Six types of evolution patterns such as “towards closed innovation” were identified. • The patterns of evolution were related to the patterns of innovation

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

    Directory of Open Access Journals (Sweden)

    Tuller Tamir

    2010-01-01

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

  17. Color pattern evolution in Vanessa butterflies (Nymphalidae: Nymphalini): non-eyespot characters.

    Science.gov (United States)

    Abbasi, Roohollah; Marcus, Jeffrey M

    2015-01-01

    A phylogenetic approach was used to study color pattern evolution in Vanessa butterflies. Twenty-four color pattern elements from the Nymphalid ground plan were identified on the dorsal and ventral surfaces of the fore- and hind wings. Eyespot characters were excluded and will be examined elsewhere. The evolution of each character was traced over a Bayesian phylogeny of Vanessa reconstructed from 7750 DNA base pairs from 10 genes. Generally, the correspondence between character states on the same surface of the two wings is stronger on the ventral side compared to the dorsal side. The evolution of character states on both sides of a wing correspond with each other in most extant species, but the correspondence between dorsal and ventral character states is much stronger in the forewing than in the hindwing. The dorsal hindwing of many species of Vanessa is covered with an extended Basal Symmetry System and the Discalis I pattern element is highly variable between species, making this wing surface dissimilar to the other wing surfaces. The Basal Symmetry System and Discalis I may contribute to behavioral thermoregulation in Vanessa. Overall, interspecific directional character state evolution of non-eyespot color patterns is relatively rare in Vanessa, with a majority of color pattern elements showing non-variable, non-directional, or ambiguous character state evolution. The ease with which the development of color patterns can be modified, including character state reversals, has likely made important contributions to the production of color pattern diversity in Vanessa and other butterfly groups.

  18. A layered framework for pattern-based ontology evolution

    OpenAIRE

    Javed, Muhammad; M. Abgaz, Yalemisew; Pahl, Claus

    2011-01-01

    The challenge of ontology-driven modelling of information components is well known in both academia and industry. In this paper, we present a novel approach to deal with customisation and abstraction of ontology-based model evolution. As a result of an empirical study, we identify a layered change operator framework based on the granularity, domain-specificity and abstraction of changes. The implementation of the operator framework is supported through layered change logs. Layered change...

  19. Adaptive evolution of facial colour patterns in Neotropical primates

    OpenAIRE

    Santana, Sharlene E.; Lynch Alfaro, Jessica; Alfaro, Michael E.

    2012-01-01

    The rich diversity of primate faces has interested naturalists for over a century. Researchers have long proposed that social behaviours have shaped the evolution of primate facial diversity. However, the primate face constitutes a unique structure where the diverse and potentially competing functions of communication, ecology and physiology intersect, and the major determinants of facial diversity remain poorly understood. Here, we provide the first evidence for an adaptive role of facial co...

  20. Contrasting patterns of karyotype and sex chromosome evolution in Lepidoptera

    OpenAIRE

    Šíchová, Jindra

    2016-01-01

    It is known that chromosomal rearrangements play an important role in speciation by limiting gene flow within and between species. Furthermore, this effect may be enhanced by involvement of sex chromosomes that are known to undergo fast evolution compared to autosomes and play a special role in speciation due to their engagement in postzygotic reproductive isolation. The work presented in this study uses various molecular-genetic and cytogenetic techniques to describe karyotype and sex chromo...

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    from earlier analyses, and all major monophyletic groups are further supported by a common gene structure in exons 1-6 and by conserved C-terminal motifs. Transcription patterns are mapped on the tree to obtain an overview of MIKC gene transcription. Genes that are transcribed only in vegetative organs...... are located in the basal part of the tree, whereas genes involved in flower development have evolved later. As the universality of the ABC model has recently been questioned, special account is paid to the expression of A-, B-, and C-class genes. Mapping of transcription patterns on the phylogeny shows all...

  2. Evolution of spiral wave and pattern formation in a vortical polarized electric field

    Institute of Scientific and Technical Information of China (English)

    Ma Jun; Yi Ming; Li Bing-Wei; Li Yan-Long

    2008-01-01

    In this paper, the evolution of the pattern transition induced by the vortical electric field (VEF) is investigated. Firstly, a scheme is suggested to generate the VEF by changing the spatial magnetic field. Secondly, the VEF is imposed on the whole medium, and the evolutions of the spiral wave and the spatiotemporal chaos are investigated by using the numerical simulation. The result confirms that the drift and the breakup of the spiral wave and the new net-like pattern are observed when different polarized fields are imposed on the whole medium respectively. Finally, the pattern transition induced by the polarized field is discussed theoretically.

  3. 2D numerical modelling of meandering channel formation

    Indian Academy of Sciences (India)

    Y Xiao; G Zhou; F S Yang

    2016-03-01

    A 2D depth-averaged model for hydrodynamic sediment transport and river morphological adjustment was established. The sediment transport submodel takes into account the influence of non-uniform sediment with bed surface armoring and considers the impact of secondary flow in the direction of bed-loadtransport and transverse slope of the river bed. The bank erosion submodel incorporates a simple simulation method for updating bank geometry during either degradational or aggradational bed evolution. Comparison of the results obtained by the extended model with experimental and field data, and numericalpredictions validate that the proposed model can simulate grain sorting in river bends and duplicate the characteristics of meandering river and its development. The results illustrate that by using its control factors, the improved numerical model can be applied to simulate channel evolution under differentscenarios and improve understanding of patterning processes.

  4. Mosaic evolution and the pattern of transitions in the hominin lineage.

    Science.gov (United States)

    Foley, Robert A

    2016-07-01

    Humans are uniquely unique, in terms of the extreme differences between them and other living organisms, and the impact they are having on the biosphere. The evolution of humans can be seen, as has been proposed, as one of the major transitions in evolution, on a par with the origins of multicellular organisms or the eukaryotic cell (Maynard Smith & Szathmáry 1997 Major transitions in evolution). Major transitions require the evolution of greater complexity and the emergence of new evolutionary levels or processes. Does human evolution meet these conditions? I explore the diversity of evidence on the nature of transitions in human evolution. Four levels of transition are proposed-baseline, novel taxa, novel adaptive zones and major transitions-and the pattern of human evolution considered in the light of these. The primary conclusions are that changes in human evolution occur continuously and cumulatively; that novel taxa and the appearance of new adaptations are not clustered very tightly in particular periods, although there are three broad transitional phases (Pliocene, Plio-Pleistocene and later Quaternary). Each phase is distinctive, with the first based on ranging and energetics, the second on technology and niche expansion, and the third on cognition and cultural processes. I discuss whether this constitutes a 'major transition' in the context of the evolutionary processes more broadly; the role of behaviour in evolution; and the opportunity provided by the rich genetic, phenotypic (fossil morphology) and behavioural (archaeological) record to examine in detail major transitions and the microevolutionary patterns underlying macroevolutionary change. It is suggested that the evolution of the hominin lineage is consistent with a mosaic pattern of change.This article is part of the themed issue 'Major transitions in human evolution'. PMID:27298474

  5. Activated sludge model No. 2d, ASM2d

    DEFF Research Database (Denmark)

    Henze, M.

    1999-01-01

    The Activated Sludge Model No. 2d (ASM2d) presents a model for biological phosphorus removal with simultaneous nitrification-denitrification in activated sludge systems. ASM2d is based on ASM2 and is expanded to include the denitrifying activity of the phosphorus accumulating organisms (PAOs...

  6. Dental patterning in the earliest sharks: Implications for tooth evolution.

    Science.gov (United States)

    Maisey, John G; Turner, Susan; Naylor, Gavin J P; Miller, Randall F

    2014-05-01

    Doliodus problematicus is the oldest known fossil shark-like fish with an almost intact dentition (Emsian, Lower Devonian, c. 397Ma). We provide a detailed description of the teeth and dentition in D. problematicus, based on tomographic analysis of NBMG 10127 (New Brunswick Museum, Canada). Comparisons with modern shark dentitions suggest that Doliodus was a ram-feeding predator with a dentition adapted to seizing and disabling prey. Doliodus provides several clues about the early evolution of the "shark-like" dentition in chondrichthyans and also raises new questions about the evolution of oral teeth in jawed vertebrates. As in modern sharks, teeth in Doliodus were replaced in a linguo-labial sequence within tooth families at fixed positions along the jaws (12-14 tooth families per jaw quadrant in NBMG 10127). Doliodus teeth were replaced much more slowly than in modern sharks. Nevertheless, its tooth formation was apparently as highly organized as in modern elasmobranchs, in which future tooth positions are indicated by synchronized expression of shh at fixed loci within the dental epithelium. Comparable dental arrays are absent in osteichthyans, placoderms, and many "acanthodians"; a "shark-like" dentition, therefore, may be a synapomorphy of chondrichthyans and gnathostomes such as Ptomacanthus. The upper anterior teeth in Doliodus were not attached to the palatoquadrates, but were instead supported by the ethmoid region of the prechordal basicranium, as in some other Paleozoic taxa (e.g., Triodus, Ptomacanthus). This suggests that the chondrichthyan dental lamina was originally associated with prechordal basicranial cartilage as well as jaw cartilage, and that the modern elasmobranch condition (in which the oral dentition is confined to the jaws) is phylogenetically advanced. Thus, oral tooth development in modern elasmobranchs does not provide a complete developmental model for chondrichthyans or gnathostomes.

  7. Dental patterning in the earliest sharks: Implications for tooth evolution.

    Science.gov (United States)

    Maisey, John G; Turner, Susan; Naylor, Gavin J P; Miller, Randall F

    2014-05-01

    Doliodus problematicus is the oldest known fossil shark-like fish with an almost intact dentition (Emsian, Lower Devonian, c. 397Ma). We provide a detailed description of the teeth and dentition in D. problematicus, based on tomographic analysis of NBMG 10127 (New Brunswick Museum, Canada). Comparisons with modern shark dentitions suggest that Doliodus was a ram-feeding predator with a dentition adapted to seizing and disabling prey. Doliodus provides several clues about the early evolution of the "shark-like" dentition in chondrichthyans and also raises new questions about the evolution of oral teeth in jawed vertebrates. As in modern sharks, teeth in Doliodus were replaced in a linguo-labial sequence within tooth families at fixed positions along the jaws (12-14 tooth families per jaw quadrant in NBMG 10127). Doliodus teeth were replaced much more slowly than in modern sharks. Nevertheless, its tooth formation was apparently as highly organized as in modern elasmobranchs, in which future tooth positions are indicated by synchronized expression of shh at fixed loci within the dental epithelium. Comparable dental arrays are absent in osteichthyans, placoderms, and many "acanthodians"; a "shark-like" dentition, therefore, may be a synapomorphy of chondrichthyans and gnathostomes such as Ptomacanthus. The upper anterior teeth in Doliodus were not attached to the palatoquadrates, but were instead supported by the ethmoid region of the prechordal basicranium, as in some other Paleozoic taxa (e.g., Triodus, Ptomacanthus). This suggests that the chondrichthyan dental lamina was originally associated with prechordal basicranial cartilage as well as jaw cartilage, and that the modern elasmobranch condition (in which the oral dentition is confined to the jaws) is phylogenetically advanced. Thus, oral tooth development in modern elasmobranchs does not provide a complete developmental model for chondrichthyans or gnathostomes. PMID:24347366

  8. Evolution at Two Levels in Fire Ants: The Relationship between Patterns of Gene Expression and Protein Sequence Evolution

    OpenAIRE

    Hunt, B. G.; Ometto, L.; Keller, L.; Goodisman, M. A. D.

    2013-01-01

    Variation in protein sequence and gene expression each contribute to phenotypic diversity, and may be subject to similar selective pressures. Eusocial insects are particularly useful for investigating the evolutionary link between protein sequence and condition-dependent patterns of gene expression because gene expression plays a central role in determining differences between eusocial insect sexes and castes. We investigated the relationship between protein coding sequence evolution and gene...

  9. Climate-linked temporal and spatial patterns in the evolution of African bovidae

    OpenAIRE

    Schikora, Tim F. (Dr. phil. nat.)

    2012-01-01

    Climate and subsequent environmental changes are regarded as one driver of species evolution. Against this background the present study investigates the evolutionary history of the mammalian family Bovidae (Cetartiodactyla, Mammalia), today the most species-rich family of large herbivores on the African continent. Temporal and spatial patterns in that group’s evolution are the focus of the present study and were investigated using methods and data deriving from multiple disciplines (palaeonto...

  10. Quantitative analysis of macroevolutionary patterning in technological evolution: Bicycle design from 1800 to 2000

    OpenAIRE

    Lake, M. W.; Venti, J.

    2009-01-01

    Book description: This volume offers an integrative approach to the application of evolutionary theory in studies of cultural transmission and social evolution and reveals the enormous range of ways in which Darwinian ideas can lead to productive empirical research, the touchstone of any worthwhile theoretical perspective. While many recent works on cultural evolution adopt a specific theoretical framework, such as dual inheritance theory or human behavioral ecology, Pattern and Process in Cu...

  11. Dorsoventral patterning in hemichordates: insights into early chordate evolution.

    Directory of Open Access Journals (Sweden)

    Christopher J Lowe

    2006-09-01

    Full Text Available We have compared the dorsoventral development of hemichordates and chordates to deduce the organization of their common ancestor, and hence to identify the evolutionary modifications of the chordate body axis after the lineages split. In the hemichordate embryo, genes encoding bone morphogenetic proteins (Bmp 2/4 and 5/8, as well as several genes for modulators of Bmp activity, are expressed in a thin stripe of ectoderm on one midline, historically called "dorsal." On the opposite midline, the genes encoding Chordin and Anti-dorsalizing morphogenetic protein (Admp are expressed. Thus, we find a Bmp-Chordin developmental axis preceding and underlying the anatomical dorsoventral axis of hemichordates, adding to the evidence from Drosophila and chordates that this axis may be at least as ancient as the first bilateral animals. Numerous genes encoding transcription factors and signaling ligands are expressed in the three germ layers of hemichordate embryos in distinct dorsoventral domains, such as pox neuro, pituitary homeobox, distalless, and tbx2/3 on the Bmp side and netrin, mnx, mox, and single-minded on the Chordin-Admp side. When we expose the embryo to excess Bmp protein, or when we deplete endogenous Bmp by small interfering RNA injections, these expression domains expand or contract, reflecting their activation or repression by Bmp, and the embryos develop as dorsalized or ventralized limit forms. Dorsoventral patterning is independent of anterior/posterior patterning, as in Drosophila but not chordates. Unlike both chordates and Drosophila, neural gene expression in hemichordates is not repressed by high Bmp levels, consistent with their development of a diffuse rather than centralized nervous system. We suggest that the common ancestor of hemichordates and chordates did not use its Bmp-Chordin axis to segregate epidermal and neural ectoderm but to pattern many other dorsoventral aspects of the germ layers, including neural cell fates

  12. Patterning and evolution of floral structures - marking time.

    Science.gov (United States)

    McKim, Sarah; Hay, Angela

    2010-08-01

    The diversity of flowering structures dazzles the eye, dominates the landscape, and invites evolutionary questions regarding the development of such variety. Comparative work in a number of genetically tractable plant species has addressed how diverse floral architectures develop, and started to reveal the balance between conservation and divergence of the patterning mechanisms responsible for when and where flowers form on a plant. We highlight findings from Petunia where conserved LFY/UFO function is under species-specific regulation, and a novel mechanism involving WOX homeodomain proteins for modulating cyme development in diverse nightshades. We also draw attention to recent findings in Arabidopsis of miRNA and chromatin-based timing mechanisms controlling floral development, and illustrate how genetic studies in Arabidopsis relatives can reveal how evolutionary changes in such mechanisms generate diversity in form. PMID:20452201

  13. Is there a pattern to oxbow lake geomorphic evolution?

    Science.gov (United States)

    Dieras, P.; Constantine, J. A.

    2012-04-01

    Oxbow lakes are located along the floodplain corridor and created after meander cutoff. They are of high ecological value as they provide relatively calm wetlands which are regularly supplied with nutrients during floods. The persistence of oxbow lakes has been observed to vary from decades to several hundreds of years but little is known about the controls on their longevity. This study aims to ascertain if there is a common pattern in the water decrease of oxbow lakes and to define the controls on the lakes' longevity. The longevity of 37 oxbow lakes from 7 rivers from different parts of the world has been studied. The Towy River (Wales), the Ain River (France) and the Sacramento River (CA, USA) are largely dominated by oxbow lakes created after chute cutoff which is the incision of a chute across the floodplain; whereas the Mississippi River (MS, USA), the Kansas River (KS, USA), the Red River (MN, USA) and the Otter Tail River (MN, USA) show a large number of neck cutoffs which occur when two meanders migrate into one another. The water surface area decrease has been measured for all the sites using aerial photographs. Results revealed that the longevity of oxbow lakes is significantly affected by the type of cutoff. The lakes formed by chute cutoff lose very rapidly most of the water surface area of the initial channel as it is reduce by >80% within the first 10 to 30 years following cutoff for most sites. The water surface area of chute cutoff shows a logarithmic decrease with a fast decrease rate following cutoff, followed by a much slower loss of water surface area. The change in water decrease rate appears to be related to the moment of obstruction of the former channel entrance by sediment aggradation. In contrast, lakes formed by neck cutoff persist for much longer in the landscape and lose 40 to 60% within the first decades but then they maintain this water surface area for longer than a century. The cutoff process is therefore the main control on the

  14. Patterns of evolution of research strands in the hydrologic sciences

    Science.gov (United States)

    Schwartz, F. W.; Fang, Y. C.; Parthasarathy, S.

    2005-03-01

    This paper examines issues of impact and innovation in groundwater research by using bibliometric data and citation analysis.The analysis is based on 3120 papers from the journal Water Resources Research with full contents and their citation data from the ISI Web of Science. The research is designed to develop a better understanding of the way citation numbers can be interpreted by scientists. Not surprisingly, the most highly cited papers appear to be pioneers in the field with papers departing significantly from what has come before and to be effective in creating similar, follow-on papers. Papers that are early contributions to a new research strand that is highly influential will be on average highly cited. However, the importance of a research strand as measured by citations seems to fall with time. The citation patterns of some classic papers show that the activity in the topical area and impact of follow-on papers gradually decline with time, which has similarities with Kuhn's ideas of revolutionary and normal science. The results of this study reinforce the importance of being a pioneer in a research strand, strategically shifting research strands, adopting strategies that can facilitate really major research breakthroughs. L'article examine les problèmes d'impact et d'innovation dans la recherche des eaux souterraines en utilisant les données bibliométriques et l'analyse des citations. L'analyse a été faite sur 3120 articles parus dans Water Resources Research en tenant compte de leur texte complet et de toutes citations parues dans l' ISI Web de la Science. Le but de la recherche a été de mieux comprendre comment le nombre des citations peut être interprété par les scientifiques. Ce n'est pas une surprise que les plus cités articles soient les articles-pionniers dans leurs domaines, qui s'écartent d'une manière significative de ce qui a été écrit auparavant et qui ont été suivi par des nouveaux articles. Les articles qui présentent une

  15. Patterns of evolution of research strands in the hydrologic sciences

    Science.gov (United States)

    Schwartz, F. W.; Fang, Y. C.; Parthasarathy, S.

    2005-03-01

    This paper examines issues of impact and innovation in groundwater research by using bibliometric data and citation analysis.The analysis is based on 3120 papers from the journal Water Resources Research with full contents and their citation data from the ISI Web of Science. The research is designed to develop a better understanding of the way citation numbers can be interpreted by scientists. Not surprisingly, the most highly cited papers appear to be pioneers in the field with papers departing significantly from what has come before and to be effective in creating similar, follow-on papers. Papers that are early contributions to a new research strand that is highly influential will be on average highly cited. However, the importance of a research strand as measured by citations seems to fall with time. The citation patterns of some classic papers show that the activity in the topical area and impact of follow-on papers gradually decline with time, which has similarities with Kuhn's ideas of revolutionary and normal science. The results of this study reinforce the importance of being a pioneer in a research strand, strategically shifting research strands, adopting strategies that can facilitate really major research breakthroughs. L'article examine les problèmes d'impact et d'innovation dans la recherche des eaux souterraines en utilisant les données bibliométriques et l'analyse des citations. L'analyse a été faite sur 3120 articles parus dans Water Resources Research en tenant compte de leur texte complet et de toutes citations parues dans l' ISI Web de la Science. Le but de la recherche a été de mieux comprendre comment le nombre des citations peut être interprété par les scientifiques. Ce n'est pas une surprise que les plus cités articles soient les articles-pionniers dans leurs domaines, qui s'écartent d'une manière significative de ce qui a été écrit auparavant et qui ont été suivi par des nouveaux articles. Les articles qui présentent une

  16. Post-orogenic evolution of the Sierras Septentrionales and the Sierras Australes and links to the evolution of the eastern Argentina South Atlantic passive continental margin constrained by low temperature thermochronometry and 2D thermokinematic modeling

    Science.gov (United States)

    Kollenz, Sebastian; Glasmacher, Ulrich Anton; Rossello, Eduardo A.

    2013-04-01

    The eastern Argentina South Atlantic passive continental margin is distinguished by a very flat topography. Out of the so called Pampean flat two mountain ranges are arising. These mountain ranges, the Sierras Australes and the Sierras Septentrionales, are located in the State of Buenos Aires south of the capital Buenos Aires. North of the Sierras Septentrionales the Salado basin is located. The Sierras Septentrionales and the Sierras Australes are also divided by a smaller intracratonic basin. Further in the South the Colorado basin is located. The Sierras Australes is a variscian fold belt originated by strong phases of metamorphosis, but till now it is unclear by how many tectonic phases the area was influenced (Tomezzoli & Vilas, 1999). It consists of Proterozoic to Paleozoic rocks. The Sierras Septentrionales consists mainly of Precambrian crystalline rocks. The Precambrian sequences are overlain by younger Sediments (Cingolani, 2010). The aim is to understand the long-term landscape evolution of the area by quantifiying erosion- and exhumation-rates and by dating ancient rock-uplift-events. Another goal is to find out how the opening of the south atlantic took effect on this region. To fulfill this goal, thermochronological techniques, such as fission-track dating and (U-Th-Sm)/He dating has been applied to samples from the region. Because there was no low-temperature thermochronology done in this area, both techniques were applied on apatites and zircons. Furthermore, numerical modeling of the cooling history has provided the data base for the quantification of the exhumation rates. The first data-set shows clusters of different ages which can be linked to tectonic activities during late Paleozoic times. Also the thermokinematic modeling is leading to new insights of the evolution of both mountain ranges. References: Renata Nela Tomezzoli and Juan Francisco Vilas (1999): Palaeomagnetic constraints on the age of deformation of the Sierras Australes thrust and

  17. Lectures on 2D gravity and 2D string theory

    International Nuclear Information System (INIS)

    This report the following topics: loops and states in conformal field theory; brief review of the Liouville theory; 2D Euclidean quantum gravity I: path integral approach; 2D Euclidean quantum gravity II: canonical approach; states in 2D string theory; matrix model technology I: method of orthogonal polynomials; matrix model technology II: loops on the lattice; matrix model technology III: free fermions from the lattice; loops and states in matrix model quantum gravity; loops and states in the C=1 matrix model; 6V model fermi sea dynamics and collective field theory; and string scattering in two spacetime dimensions

  18. Temporal evolution of the chemical structure during the pattern transfer by ion-beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ha, N.-B.; Jeong, S.; Yu, S.; Ihm, H.-I.; Kim, J.-S.

    2015-01-01

    Highlights: • Chemical analyses of the individual nano structures simultaneously with the investigation of their morphological evolution were performed. • Degradation of the transferred pattern starts before the overlayer is fully removed. • The chemical analysis reveals the severe reduction of the sputter yield of the material forming the overlayer near the interface due to the compound formation, requesting caution in the practice of the pattern transfer. - Abstract: Ru films patterned by ion-beam sputtering (IBS) serve as sacrificial masks for the transfer of the patterns to Si(1 0 0) and metallic glass substrates by continued IBS. Under the same sputter condition, however, both bare substrates remain featureless. Chemical analyses of the individual nano structures simultaneously with the investigation of their morphological evolution reveal that the pattern transfer, despite its apparent success, suffers from premature degradation before the mask is fully removed by IBS. Moreover, the residue of the mask or Ru atoms stubbornly remains near the surface, resulting in unintended doping or alloying of both patterned substrates.

  19. Derivation of a Differential Equation Exhibiting Replicative Time-Evolution Patterns by Inverse Ultra-Discretization

    Science.gov (United States)

    Tanaka, Hiroshi; Nakajima, Asumi; Nishiyama, Akinobu; Tokihiro, Tetsuji

    2009-03-01

    A differential equation exhibiting replicative time-evolution patterns is derived by inverse ultradiscretizatrion of Fredkin’s game, which is one of the simplest replicative cellular automaton (CA) in two dimensions. This is achieved by employing a certain filter and a clock function in the equation. These techniques are applicable to the inverse ultra-discretization (IUD) of other CA and stabilize the time-evolution of the obtained differential equation. Application to the game of life, another CA in two dimensions, is also presented.

  20. 2D photonic-crystal optomechanical nanoresonator.

    Science.gov (United States)

    Makles, K; Antoni, T; Kuhn, A G; Deléglise, S; Briant, T; Cohadon, P-F; Braive, R; Beaudoin, G; Pinard, L; Michel, C; Dolique, V; Flaminio, R; Cagnoli, G; Robert-Philip, I; Heidmann, A

    2015-01-15

    We present the optical optimization of an optomechanical device based on a suspended InP membrane patterned with a 2D near-wavelength grating (NWG) based on a 2D photonic-crystal geometry. We first identify by numerical simulation a set of geometrical parameters providing a reflectivity higher than 99.8% over a 50-nm span. We then study the limitations induced by the finite value of the optical waist and lateral size of the NWG pattern using different numerical approaches. The NWG grating, pierced in a suspended InP 265-nm thick membrane, is used to form a compact microcavity involving the suspended nanomembrane as an end mirror. The resulting cavity has a waist size smaller than 10 μm and a finesse in the 200 range. It is used to probe the Brownian motion of the mechanical modes of the nanomembrane. PMID:25679837

  1. Characteristics of pattern formation and evolution in approximations of Physarum transport networks.

    Science.gov (United States)

    Jones, Jeff

    2010-01-01

    Most studies of pattern formation place particular emphasis on its role in the development of complex multicellular body plans. In simpler organisms, however, pattern formation is intrinsic to growth and behavior. Inspired by one such organism, the true slime mold Physarum polycephalum, we present examples of complex emergent pattern formation and evolution formed by a population of simple particle-like agents. Using simple local behaviors based on chemotaxis, the mobile agent population spontaneously forms complex and dynamic transport networks. By adjusting simple model parameters, maps of characteristic patterning are obtained. Certain areas of the parameter mapping yield particularly complex long term behaviors, including the circular contraction of network lacunae and bifurcation of network paths to maintain network connectivity. We demonstrate the formation of irregular spots and labyrinthine and reticulated patterns by chemoattraction. Other Turing-like patterning schemes were obtained by using chemorepulsion behaviors, including the self-organization of regular periodic arrays of spots, and striped patterns. We show that complex pattern types can be produced without resorting to the hierarchical coupling of reaction-diffusion mechanisms. We also present network behaviors arising from simple pre-patterning cues, giving simple examples of how the emergent pattern formation processes evolve into networks with functional and quasi-physical properties including tensionlike effects, network minimization behavior, and repair to network damage. The results are interpreted in relation to classical theories of biological pattern formation in natural systems, and we suggest mechanisms by which emergent pattern formation processes may be used as a method for spatially represented unconventional computation. PMID:20067403

  2. Comparison patterns of 4 T1 antigens recognized by humoral immune response mediated by IgG and IgM antibodies in female and male mice with breast cancer using 2D-immnunoblots.

    Science.gov (United States)

    Díaz-Zaragoza, Mariana; Hernández-Ávila, Ricardo; Govezensky, Tzipe; Mendoza, Luis; Meneses-Ruíz, Dulce María; Ostoa-Saloma, Pedro

    2015-09-01

    The early detection of cancer is one of the most promising approaches to reduce its growing burden and develop a curative treatment before the tumor is established. The early diagnosis of breast cancer is the most demanding of all tumors, because it is the most common cancer in women worldwide. We have described a new approach to analyze humoral immune reactions against 4 T1 cell antigens in female mice, reporting that the IgG and IgM responses differed and varied over time and between individuals. In this study, we compared and analyzed the detection of tumor antigens with IgG and IgM from the sera of male mice that were injected with 4 T1 cells into the mammary gland nipple in 2D immunoblot images. The variability in IgM and IgG responses in female and male mice with breast cancer at various stages of disease was characterized, and the properties with regard to antigen recognition were correlated statistically with variables that were associated with the individuals and tumors. The ensuing IgG and IgM responses differed. Only the IgG response decreased over time in female mice--not in male mice. The IgM response was maintained during tumor development in both sexes. Each mouse had a specific pattern of antigen recognition--ie, an immunological signature--represented by a unique set of antigen spots that were recognized by IgM or IgG. These data would support that rationale IgM is a better tool for early diagnosis, because it is not subject to immunosuppression like IgG in female mice with breast cancer. PMID:26026196

  3. Time Curves: Folding Time to Visualize Patterns of Temporal Evolution in Data.

    Science.gov (United States)

    Bach, Benjamin; Shi, Conglei; Heulot, Nicolas; Madhyastha, Tara; Grabowski, Tom; Dragicevic, Pierre

    2016-01-01

    We introduce time curves as a general approach for visualizing patterns of evolution in temporal data. Examples of such patterns include slow and regular progressions, large sudden changes, and reversals to previous states. These patterns can be of interest in a range of domains, such as collaborative document editing, dynamic network analysis, and video analysis. Time curves employ the metaphor of folding a timeline visualization into itself so as to bring similar time points close to each other. This metaphor can be applied to any dataset where a similarity metric between temporal snapshots can be defined, thus it is largely datatype-agnostic. We illustrate how time curves can visually reveal informative patterns in a range of different datasets.

  4. 2D-hahmoanimaation toteuttamistekniikat

    OpenAIRE

    Smolander, Aku

    2009-01-01

    Opinnäytetyössä tutkitaan erilaisia 2D-hahmoanimaation toteuttamistekniikoita. Aluksi luodaan yleiskatsaus animoinnin historiaan ja tekniikoihin piirtämisestä mallintamiseen. Alkukatsauksen jälkeen tutkitaan 2D-hahmon suunnittelua ja liikkeitä koskevia sääntöjä. Hahmoanimaation liikkeissä huomionarvoisia asioita ovat muun muassa ajastus, liioittelu, ennakointi ja painovoima. Seuraavaksi perehdytään itse 2D-hahmoanimaation toteuttamistekniikoihin. Tavoitteena on selvittää, tutkia ja vertailla ...

  5. Evolution of Spatial Pattern of China’s Urbanization and Its Impacts on Regional Development

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Along with the remarkable economic growth,China has been experiencing a rapid urbanization in the past 60 years.However,the development of urbanization was not coordinated with regional development and the distributions of population and economy were discrete.With the method of centroid analysis,this paper demonstrates the spatial pattern of China’s urbanization and its evolution thereof from 1952 to 2005.Two indices are set up to represent the coupling states of three centroids,by which the impacts of urbanization on regional development are analyzed.In the end,from the angle of spatial pattern,this paper summarizes the characteristics of China’s urbanization,its evolution and its interaction with economic development,and then gives several suggestions on the population policy for the balanced regional development in the country.

  6. Phylomemetic patterns in science evolution--the rise and fall of scientific fields.

    Science.gov (United States)

    Chavalarias, David; Cointet, Jean-Philippe

    2013-01-01

    We introduce an automated method for the bottom-up reconstruction of the cognitive evolution of science, based on big-data issued from digital libraries, and modeled as lineage relationships between scientific fields. We refer to these dynamic structures as phylomemetic networks or phylomemies, by analogy with biological evolution; and we show that they exhibit strong regularities, with clearly identifiable phylomemetic patterns. Some structural properties of the scientific fields - in particular their density -, which are defined independently of the phylomemy reconstruction, are clearly correlated with their status and their fate in the phylomemy (like their age or their short term survival). Within the framework of a quantitative epistemology, this approach raises the question of predictibility for science evolution, and sketches a prototypical life cycle of the scientific fields: an increase of their cohesion after their emergence, the renewal of their conceptual background through branching or merging events, before decaying when their density is getting too low. PMID:23408947

  7. Phylomemetic patterns in science evolution--the rise and fall of scientific fields.

    Directory of Open Access Journals (Sweden)

    David Chavalarias

    Full Text Available We introduce an automated method for the bottom-up reconstruction of the cognitive evolution of science, based on big-data issued from digital libraries, and modeled as lineage relationships between scientific fields. We refer to these dynamic structures as phylomemetic networks or phylomemies, by analogy with biological evolution; and we show that they exhibit strong regularities, with clearly identifiable phylomemetic patterns. Some structural properties of the scientific fields - in particular their density -, which are defined independently of the phylomemy reconstruction, are clearly correlated with their status and their fate in the phylomemy (like their age or their short term survival. Within the framework of a quantitative epistemology, this approach raises the question of predictibility for science evolution, and sketches a prototypical life cycle of the scientific fields: an increase of their cohesion after their emergence, the renewal of their conceptual background through branching or merging events, before decaying when their density is getting too low.

  8. Color-pattern evolution in response to environmental stress in butterflies

    Directory of Open Access Journals (Sweden)

    Atsuki eHiyama

    2012-02-01

    Full Text Available It is generally accepted that butterfly wing color patterns have ecological and behavioral functions that evolved through natural selection. However, particular wing color patterns may physiologically be produced in response to environmental stress without significant function. These patterns would represent an extreme expression of phenotypic plasticity and can eventually be fixed genetically in a population. Here, three such cases in butterflies are concisely reviewed and their possible mechanisms of genetic assimilation are discussed. First, certain modified color pattern of Vanessa indica induced by temperature treatments resembles the natural color patterns of its closely related species of the genus Vanessa (sensu stricto. Second, a different type of color-pattern modification can be induced in Vanessa cardui as a result of a general stress response, which is very similar to the natural color pattern of its sister species Vanessa kershawi. Third, a field observation was reported, together with experimental support, to show that the color-pattern diversity of a regional population of Zizeeria maha increased at the northern range margin of this species in response to temperature stress. In these three cases, modified color patterns are unlikely to have significant functions, and these cases suggest that phenotypic plasticity plays an important role in butterfly wing color-pattern evolution. A neutral or non-functional trait can be assimilated genetically if it is linked, like a parasitic trait, with another functional trait. In addition, it is possible that environmental stress causes epigenetic modifications of genes related to color patterns and that their transgenerational inheritance facilitates the process of genetic assimilation of a neutral or non-functional trait.

  9. A comparative approach reveals differences in patterns of numt insertion during hominoid evolution

    OpenAIRE

    Jensen-Seaman, M.I.; Wildschutte, J.H.; Soto-Calderón, I.D.; Anthony, N. M.

    2009-01-01

    Nuclear integrations of mitochondrial DNA (numts) are widespread among eukaryotes although their prevalence differs greatly among taxa. Most knowledge of numt evolution comes from analyses of whole genome sequences of single species, or more recently from genomic comparisons across vast phylogenetic distances. Here, we employ a comparative approach using human and chimpanzee genome sequence data to infer differences in the patterns and processes underlying numt integrations. We identified 66 ...

  10. Colour pattern homology and evolution in Vanessa butterflies (Nymphalidae: Nymphalini): eyespot characters.

    Science.gov (United States)

    Abbasi, R; Marcus, J M

    2015-11-01

    Ocelli are serially repeated colour patterns on the wings of many butterflies. Eyespots are elaborate ocelli that function in predator avoidance and deterrence as well as in mate choice. A phylogenetic approach was used to study ocelli and eyespot evolution in Vanessa butterflies, a genus exhibiting diverse phenotypes among these serial homologs. Forty-four morphological characters based on eyespot number, arrangement, shape and the number of elements in each eyespot were defined and scored. Ocelli from eight wing cells on the dorsal and ventral surfaces of the forewing and hindwing were evaluated. The evolution of these characters was traced over a phylogeny of Vanessa based on 7750 DNA base pairs from 10 genes. Our reconstruction predicts that the ancestral Vanessa had 5 serially arranged ocelli on all four wing surfaces. The ancestral state on the dorsal forewing and ventral hindwing was ocelli arranged in two heterogeneous groups. On the dorsal hindwing, the ancestral state was either homogenous or ocelli arranged in two heterogeneous groups. On the ventral forewing, we determined that the ancestral state was organized into three heterogeneous groups. In Vanessa, almost all ocelli are individuated and capable of independent evolution relative to other colour patterns except for the ocelli in cells -1 and 0 on the dorsal and ventral forewings, which appear to be constrained to evolve in parallel. The genus Vanessa is a good model system for the study of serial homology and the interaction of selective forces with developmental architecture to produce diversity in butterfly colour patterns.

  11. Antigenic Patterns and Evolution of the Human Influenza A (H1N1) Virus.

    Science.gov (United States)

    Liu, Mi; Zhao, Xiang; Hua, Sha; Du, Xiangjun; Peng, Yousong; Li, Xiyan; Lan, Yu; Wang, Dayan; Wu, Aiping; Shu, Yuelong; Jiang, Taijiao

    2015-09-28

    The influenza A (H1N1) virus causes seasonal epidemics that result in severe illnesses and deaths almost every year. A deep understanding of the antigenic patterns and evolution of human influenza A (H1N1) virus is extremely important for its effective surveillance and prevention. Through development of antigenicity inference method for human influenza A (H1N1), named PREDAC-H1, we systematically mapped the antigenic patterns and evolution of the human influenza A (H1N1) virus. Eight dominant antigenic clusters have been inferred for seasonal H1N1 viruses since 1977, which demonstrated sequential replacements over time with a similar pattern in Asia, Europe and North America. Among them, six clusters emerged first in Asia. As for China, three of the eight antigenic clusters were detected in South China earlier than in North China, indicating the leading role of South China in H1N1 transmission. The comprehensive view of the antigenic evolution of human influenza A (H1N1) virus can help formulate better strategy for its prevention and control.

  12. Correlated evolution of short wavelength sensitive photoreceptor sensitivity and color pattern in Lake Malawi cichlids

    Directory of Open Access Journals (Sweden)

    Michael J. Pauers

    2016-02-01

    Full Text Available For evolutionary ecologists, the holy grail of visual ecology is to establish an unambiguous link between photoreceptor sensitivity, the spectral environment, and the perception of specific visual stimuli (e.g., mates, food, predators, etc.. Due to the bright nuptial colors of the males, and the role female mate choice plays in their evolution, the haplochromine cichlid fishes of the African great lakes are favorite research subjects for such investigations. Despite this attention, current evidence is equivocal; while distinct correlations among photoreceptor sensitivity, photic environment, and male coloration exist in Lake Victorian haplochromines, attempts to find such correlations in Lake Malawian cichlids have failed. Lake Malawi haplochromines have a wide variability in their short-wavelength-sensitive photoreceptors, especially compared to their mid- and long-wavelength-sensitive photoreceptors; these cichlids also vary in the degree to which they express one of three basic color patterns (vertical bars, horizontal stripes, and solid patches of colors, each of which is likely used in a different form of communication. Thus, we hypothesize that, in these fishes, spectral sensitivity and color pattern have evolved in a correlated fashion to maximize visual communication; specifically, ultraviolet sensitivity should be found in vertically-barred species to promote ‘private’ communication, while striped species should be less likely to have ultraviolet sensitivity, since their color pattern carries ‘public’ information. Using phylogenetic independent contrasts, we found that barred species had strong sensitivity to ultraviolet wavelengths, but that striped species typically lacked sensitivity to ultraviolet light. Further, the only variable, even when environmental variables were simultaneously considered, that could predict ultraviolet sensitivity was color pattern. We also found that, using models of correlated evolution, color

  13. An evolution from 3D face-centered-cubic ZnSnO3 nanocubes to 2D orthorhombic ZnSnO3 nanosheets with excellent gas sensing performance

    International Nuclear Information System (INIS)

    We have successfully observed the development of three-dimensional (3D) face-centered-cubic ZnSnO3 into two-dimensional (2D) orthorhombic ZnSnO3 nanosheets, which is the first observation of 2D ZnSnO3 nanostructures to date. The synthesis from 3D to 2D nanostructures is realized by the dual-hydrolysis-assisted liquid precipitation reaction and subsequent hydrothermal treatment. The time-dependent morphology indicates the transformation via a ‘dissolution–recrystallization’ mechanism, accompanied by a ‘further growth’ process. Furthermore, the 2D ZnSnO3 nanosheets consist of smaller sized nanoflakes. This further increases the special specific surface area and facilitates their application in gas sensing. The 2D ZnSnO3 nanosheets exhibit excellent gas sensing properties, especially through their ultra-fast response and recovery. When exposed to ethanol and acetone, the response rate is as fast as 0.26 s and 0.18 s, respectively, and the concentration limit can reach as low as 50 ppb of ethanol. All these results are much better than those reported so far. Our experimental results indicate an efficient approach to realize high-performance gas sensors. (paper)

  14. Refractory nonconvulsive status epilepticus in coma: analysis of the evolution of ictal patterns

    Directory of Open Access Journals (Sweden)

    Paulo Breno Noronha Liberalesso

    2012-07-01

    Full Text Available OBJECTIVE: Nonconvulsive status epilepticus (NCSE is currently considered as one of the most frequent types of status epilepticus (SE. The objective of the present study was to identify the natural history of the electrographical evolution of refractory NCSE and to establish the relationship between ictal patterns and prognosis. METHODS: We analyzed, retrospectively, 14 patients with loss of consciousness and NCSE. The ictal patterns were classified as discrete seizures (DS, merging seizures (MS, continuous ictal discharges (CID, continuous ictal discharges with flat periods (CID-F, and periodic lateralized epileptiform discharges (PLEDs. RESULTS: The ictal patterns were DS (n=7; 50.0%, PLEDs (n=3; 1.4%, CID (n=2; 14.3%, MS (n=1; 7.1%, and CID-F (n=1; 7.1%. CONCLUSIONS: NCSE electrographic findings are heterogeneous and do not follow a stereotyped sequence. PLEDs were related to a higher probability of neurological morbidity and mortality.

  15. MtDNA mutation pattern in tumors and human evolution are shaped by similar selective constraints.

    Science.gov (United States)

    Zhidkov, Ilia; Livneh, Erez A; Rubin, Eitan; Mishmar, Dan

    2009-04-01

    Multiple human mutational landscapes of normal and cancer conditions are currently available. However, while the unique mutational patterns of tumors have been extensively studied, little attention has been paid to similarities between malignant and normal conditions. Here we compared the pattern of mutations in the mitochondrial genomes (mtDNAs) of cancer (98 sequences) and natural populations (2400 sequences). De novo mtDNA mutations in cancer preferentially colocalized with ancient variants in human phylogeny. A significant portion of the cancer mutations was organized in recurrent combinations (COMs), reaching a length of seven mutations, which also colocalized with ancient variants. Thus, by analyzing similarities rather than differences in patterns of mtDNA mutations in tumor and human evolution, we discovered evidence for similar selective constraints, suggesting a functional potential for these mutations.

  16. Competition, transmission and pattern evolution: A network analysis of global oil trade

    International Nuclear Information System (INIS)

    This paper studies the competition among oil importers using complex network theory, combined with several alternative measures of competition intensity, to analyze the evolution of the pattern and transmission of oil-trading competition. The results indicate that oil trade has formed a global competition pattern and that the role played by the Asian-Pacific region in the evolution of this competition pattern is becoming increasingly prominent. In addition, global competition intensity has continued to rise, and non-OECD countries have become the main driving force for this increase in global competition intensity. The large oil importers are the most significant parts of the global oil-trading competition pattern. They are not only the major participants in the competition for oil resources but also play important roles in the transmission of oil-trading competition. China and the United States especially display the feature of globalization, whose impacts of transmission reach across the whole oil-trading competition network. Finally, a “5C” (changeability, contestability, cooperation, commitment and circumstances) policy framework is put forward to maintain the stability of oil trade and improve the energy security of oil importers in various aspects. - Highlights: • An oil-trading competition network is constructed using complex network theory. • Oil trade has formed a global competition pattern and its intensity has kept rising. • The status of the Asian-Pacific region in the competition pattern becomes prominent. • Large oil importers play important roles in transmitting the trading competition. • A “5C” policy framework is put forward to cope with the intensive competition

  17. Lineage tracing of the bivalve shell field with special interest in the descendants of the 2d blastomere.

    Science.gov (United States)

    Mohri, Masakuni; Hashimoto, Naoki; Wada, Hiroshi

    2016-03-01

    By evolving bilaterally separated shell plates, bivalves acquired a unique body plan in which their soft tissues are completely protected by hard shell plates. In this unique body plan, mobility between the separated shell plates is provided by novel structures such as a ligament and adductor muscles. As a first step towards understanding how the bivalve body plan was established, we investigated the development of the separated shell plates and ligament. Over 100 years ago, it was hypothesized that the development of separated shell plates is tightly linked with the unique cell cleavage (division) pattern of bivalves during development, wherein each bilateral daughter cell of the 2d descendant 2d(1121) develops into one of the bilateral shell fields. In this study, we tested this hypothesis by tracing the cell lineages of the Japanese purple mussel Septifer virgatus. Although the shell fields were found to be exclusively derived from the bilateral descendant cells of 2d: 2d(11211) and 2d(11212), the descendants of these cells were not restricted to shell fields alone, nor were they confined to the left or right side of the shell field based on their lineage. Our study demonstrated that ligament cells are also derived from 2d(11211) and 2d(11212), indicating that the ligament cells emerged as a subpopulation of shell field cells. This also suggests that the establishment of the novel developmental system for the ligament cells was critical for the evolution of the unique body plan of bivalves.

  18. Accretion Disks Phase Transitions 2-D or not 2-D?

    CERN Document Server

    Abramowicz, M A; Igumenshchev, I V; Abramowicz, Marek Artur; Bjornsson, Gunnlaugur; Igumenshchev, Igor V.

    2000-01-01

    We argue that the proper way to treat thin-thick accretion-disk transitions should take into account the 2-D nature of the problem. We illustrate the physical inconsistency of the 1-D vertically integrated approach by discussing a particular example of the convective transport of energy.

  19. The fundamental units, processes and patterns of evolution, and the Tree of Life conundrum

    Directory of Open Access Journals (Sweden)

    Wolf Yuri I

    2009-09-01

    Full Text Available Abstract Background The elucidation of the dominant role of horizontal gene transfer (HGT in the evolution of prokaryotes led to a severe crisis of the Tree of Life (TOL concept and intense debates on this subject. Concept Prompted by the crisis of the TOL, we attempt to define the primary units and the fundamental patterns and processes of evolution. We posit that replication of the genetic material is the singular fundamental biological process and that replication with an error rate below a certain threshold both enables and necessitates evolution by drift and selection. Starting from this proposition, we outline a general concept of evolution that consists of three major precepts. 1. The primary agency of evolution consists of Fundamental Units of Evolution (FUEs, that is, units of genetic material that possess a substantial degree of evolutionary independence. The FUEs include both bona fide selfish elements such as viruses, viroids, transposons, and plasmids, which encode some of the information required for their own replication, and regular genes that possess quasi-independence owing to their distinct selective value that provides for their transfer between ensembles of FUEs (genomes and preferential replication along with the rest of the recipient genome. 2. The history of replication of a genetic element without recombination is isomorphously represented by a directed tree graph (an arborescence, in the graph theory language. Recombination within a FUE is common between very closely related sequences where homologous recombination is feasible but becomes negligible for longer evolutionary distances. In contrast, shuffling of FUEs occurs at all evolutionary distances. Thus, a tree is a natural representation of the evolution of an individual FUE on the macro scale, but not of an ensemble of FUEs such as a genome. 3. The history of life is properly represented by the "forest" of evolutionary trees for individual FUEs (Forest of Life, or

  20. Rapid identification of amino acid types in proteins using phase modulated 2D HN(CACB) and 2D HN(COCACB)

    Science.gov (United States)

    Dubey, Abhinav; Mondal, Somnath; Chandra, Kousik; Atreya, Hanudatta S.

    2016-06-01

    We present a simple approach to rapidly identify amino acid types in proteins from a 2D spectrum. The method is based on the fact that 13Cβ chemical shifts of different amino acid types fall in distinct spectral regions. By evolving the 13C chemical shifts in the conventional HNCACB or HN(CO)CACB type experiment for a single specified delay period, the phase of the cross peaks of different amino acid residues are modulated depending on their 13Cβ shift values. Following this specified evolution period, the 2D HN projections of these experiments are acquired. The 13C evolution period can be chosen such that all residues belonging to a given set of amino acid types have the same phase pattern (positive or negative) facilitating their identification. This approach does not require the preparation of any additional samples, involves the analysis of 2D [15N-1H] HSQC-type spectra obtained from the routinely used triple resonance experiments with minor modifications, and is applicable to deuterated proteins. The method will be useful for quick assignment of signals that shift during ligand binding or in combination with selective labeling/unlabeling approaches for identification of amino acid types to aid the sequential assignment process.

  1. Using experimental evolution to explore natural patterns between bacterial motility and resistance to bacteriophages.

    Science.gov (United States)

    Koskella, Britt; Taylor, Tiffany B; Bates, Jennifer; Buckling, Angus

    2011-11-01

    Resistance of bacteria to phages may be gained by alteration of surface proteins to which phages bind, a mechanism that is likely to be costly as these molecules typically have critical functions such as movement or nutrient uptake. To address this potential trade-off, we combine a systematic study of natural bacteria and phage populations with an experimental evolution approach. We compare motility, growth rate and susceptibility to local phages for 80 bacteria isolated from horse chestnut leaves and, contrary to expectation, find no negative association between resistance to phages and bacterial motility or growth rate. However, because correlational patterns (and their absence) are open to numerous interpretations, we test for any causal association between resistance to phages and bacterial motility using experimental evolution of a subset of bacteria in both the presence and absence of naturally associated phages. Again, we find no clear link between the acquisition of resistance and bacterial motility, suggesting that for these natural bacterial populations, phage-mediated selection is unlikely to shape bacterial motility, a key fitness trait for many bacteria in the phyllosphere. The agreement between the observed natural pattern and the experimental evolution results presented here demonstrates the power of this combined approach for testing evolutionary trade-offs.

  2. Patterns of philopatry and longevity contribute to the evolution of post-reproductive lifespan in mammals.

    Science.gov (United States)

    Nichols, H J; Zecherle, L; Arbuckle, K

    2016-02-01

    While menopause has long been known as a characteristic trait of human reproduction, evidence for post-reproductive lifespan (PRLS) has recently been found in other mammals. Adaptive and non-adaptive hypotheses have been proposed to explain the evolution of PRLS, but formal tests of these are rare. We use a phylogenetic approach to evaluate hypotheses for the evolution of PRLS among mammals. In contrast to theoretical models predicting that PRLS may be promoted by male philopatry (which increases relatedness between a female and her group in old age), we find little evidence that male philopatry led to the evolution of a post-reproductive period. However, the proportion of life spent post-reproductive was related to lifespan and patterns of philopatry, suggesting that the duration of PRLS may be impacted by both non-adaptive and adaptive processes. Finally, the proportion of females experiencing PRLS was higher in species with male philopaty and larger groups, in accordance with adaptive models of PRLS. We suggest that the origin of PRLS primarily follows the non-adaptive 'mismatch' scenario, but that patterns of philopatry may subsequently confer adaptive benefits of late-life helping.

  3. Changes in Diversification Patterns and Signatures of Selection during the Evolution of Murinae-Associated Hantaviruses

    Directory of Open Access Journals (Sweden)

    Guillaume Castel

    2014-03-01

    Full Text Available In the last 50 years, hantaviruses have significantly affected public health worldwide, but the exact extent of the distribution of hantavirus diseases, species and lineages and the risk of their emergence into new geographic areas are still poorly known. In particular, the determinants of molecular evolution of hantaviruses circulating in different geographical areas or different host species are poorly documented. Yet, this understanding is essential for the establishment of more accurate scenarios of hantavirus emergence under different climatic and environmental constraints. In this study, we focused on Murinae-associated hantaviruses (mainly Seoul Dobrava and Hantaan virus using sequences available in GenBank and conducted several complementary phylogenetic inferences. We sought for signatures of selection and changes in patterns and rates of diversification in order to characterize hantaviruses’ molecular evolution at different geographical scales (global and local. We then investigated whether these events were localized in particular geographic areas. Our phylogenetic analyses supported the assumption that RNA virus molecular variations were under strong evolutionary constraints and revealed changes in patterns of diversification during the evolutionary history of hantaviruses. These analyses provide new knowledge on the molecular evolution of hantaviruses at different scales of time and space.

  4. Cell state switching factors and dynamical patterning modules: complementary mediators of plasticity in development and evolution

    Indian Academy of Sciences (India)

    Stuart A Newman; Ramray Bhat; Nadejda V Mezentseva

    2009-10-01

    Ancient metazoan organisms arose from unicellular eukaryotes that had billions of years of genetic evolution behind them. The transcription factor networks present in single-celled ancestors at the origin of the Metazoa (multicellular animals) were already capable of mediating the switching of the unicellular phenotype among alternative states of gene activity in response to environmental conditions. Cell differentiation, therefore, had its roots in phenotypic plasticity, with the ancient regulatory proteins acquiring new targets over time and evolving into the ``developmental transcription factors” (DTFs) of the ``developmental-genetic toolkit.” In contrast, the emergence of pattern formation and morphogenesis in the Metazoa had a different trajectory. Aggregation of unicellular metazoan ancestors changed the organisms’ spatial scale, leading to the first ``dynamical patterning module” (DPM): cell-cell adhesion. Following this, other DPMs (defined as physical forces and processes pertinent to the scale of the aggregates mobilized by a set of toolkit gene products distinct from the DTFs), transformed simple cell aggregates into hollow, multilayered, segmented, differentiated and additional complex structures, with minimal evolution of constituent genes. Like cell differentiation, therefore, metazoan morphologies also originated from plastic responses of cells and tissues. Here we describe examples of DTFs and most of the important DPMs, discussing their complementary roles in the evolution of developmental mechanisms. We also provide recently characterized examples of DTFs in cell type switching and DPMs in morphogenesis of avian limb bud mesenchyme, an embryo-derived tissue that retains a high degree of developmental plasticity.

  5. Distinctive patterns of evolution of the δ-globin gene (HBD in primates.

    Directory of Open Access Journals (Sweden)

    Ana Moleirinho

    Full Text Available In most vertebrates, hemoglobin (Hb is a heterotetramer composed of two dissimilar globin chains, which change during development according to the patterns of expression of α- and β-globin family members. In placental mammals, the β-globin cluster includes three early-expressed genes, ε(HBE-γ(HBG-ψβ(HBBP1, and the late expressed genes, δ (HBD and β (HBB. While HBB encodes the major adult β-globin chain, HBD is weakly expressed or totally silent. Paradoxically, in human populations HBD shows high levels of conservation typical of genes under strong evolutionary constraints, possibly due to a regulatory role in the fetal-to-adult switch unique of Anthropoid primates. In this study, we have performed a comprehensive phylogenetic and comparative analysis of the two adult β-like globin genes in a set of diverse mammalian taxa, focusing on the evolution and functional divergence of HBD in primates. Our analysis revealed that anthropoids are an exception to a general pattern of concerted evolution in placental mammals, showing a high level of sequence conservation at HBD, less frequent and shorter gene conversion events. Moreover, this lineage is unique in the retention of a functional GATA-1 motif, known to be involved in the control of the developmental expression of the β-like globin genes. We further show that not only the mode but also the rate of evolution of the δ-globin gene in higher primates are strictly associated with the fetal/adult β-cluster developmental switch. To gain further insight into the possible functional constraints that have been shaping the evolutionary history of HBD in primates, we calculated dN/dS (ω ratios under alternative models of gene evolution. Although our results indicate that HBD might have experienced different selective pressures throughout primate evolution, as shown by different ω values between apes and Old World Monkeys + New World Monkeys (0.06 versus 0.43, respectively, these estimates

  6. Axial segregation of granular media rotated in a drum mixer: Pattern evolution

    International Nuclear Information System (INIS)

    In the traditional axial segregation effect, a homogeneous mixture of different types of granular material rotated in a drum mixer segregates into surface bands of relatively pure single concentrations along the axis of rotation. This effect primarily has been studied with respect to the initial segregation. However, the initial pattern is not stable, but evolves in time with continued rotation through metastable states of fewer and fewer bands. We describe two experimental studies of this evolution that provide a more complete picture of the dynamics involved in the pattern progression. The use of a charge coupled device camera in conjunction with digital analysis techniques provides a quantitative measure of the state of the surface as a function of time, while magnetic resonance imaging techniques provide a noninvasive method for studying the segregation beneath the surface. These methods indicate that the underlying mechanisms for the pattern evolution may originate in the bulk of the material, beneath the avalanching surface. copyright 1997 The American Physical Society

  7. The Formation, Movement and Evolution Pattern of Jurassic Terrestrial Deposit Basin in Daqingshan Region

    Institute of Scientific and Technical Information of China (English)

    PENG Xiangdong; XU Zhongyuan; LIU Zhenghong

    2001-01-01

    The authors have reconstructed the original shape of Jurassic basin in Daqingshan region and discussed the movement and evolution pattern of the basin. The basin developed between Paleozoic strata sliver and metamorphic rock sliver in late stage of Early Jurassic and extended in latitude direction. The palco - terrene of the basin is higher in north and west than south and east. The boundary of basin is largest in Changhangou stage of Middle Jurassic. After middle Jurassic, the region took place Yenshan movement, and then the basin changed obviously from weakly extending environment of Early and Middle Jurassic to extruding environment of late Jurassic, and the paleoclimate of the basin changed from warmth and wetness to dry. The basin finished the evolution history in the late stage of Late Jurassic with the development of thrust.

  8. Differential evolution of MAGE genes based on expression pattern and selection pressure.

    Directory of Open Access Journals (Sweden)

    Qi Zhao

    Full Text Available Starting from publicly-accessible datasets, we have utilized comparative and phylogenetic genome analyses to characterize the evolution of the human MAGE gene family. Our characterization of genomic structures in representative genomes of primates, rodents, carnivora, and macroscelidea indicates that both Type I and Type II MAGE genes have undergone lineage-specific evolution. The restricted expression pattern in germ cells of Type I MAGE orthologs is observed throughout evolutionary history. Unlike Type II MAGEs that have conserved promoter sequences, Type I MAGEs lack promoter conservation, suggesting that epigenetic regulation is a central mechanism for controlling their expression. Codon analysis shows that Type I but not Type II MAGE genes have been under positive selection. The combination of genomic and expression analysis suggests that Type 1 MAGE promoters and genes continue to evolve in the hominin lineage, perhaps towards functional diversification or acquiring additional specific functions, and that selection pressure at codon level is associated with expression spectrum.

  9. Evolution-development congruence in pattern formation dynamics: Bifurcations in gene expression and regulation of networks structures.

    Science.gov (United States)

    Kohsokabe, Takahiro; Kaneko, Kunihiko

    2016-01-01

    Search for possible relationships between phylogeny and ontogeny is important in evolutionary-developmental biology. Here we uncover such relationships by numerical evolution and unveil their origin in terms of dynamical systems theory. By representing developmental dynamics of spatially located cells with gene expression dynamics with cell-to-cell interaction under external morphogen gradient, gene regulation networks are evolved under mutation and selection with the fitness to approach a prescribed spatial pattern of expressed genes. For most numerical evolution experiments, evolution of pattern over generations and development of pattern by an evolved network exhibit remarkable congruence. Both in the evolution and development pattern changes consist of several epochs where stripes are formed in a short time, while for other temporal regimes, pattern hardly changes. In evolution, these quasi-stationary regimes are generations needed to hit relevant mutations, while in development, they are due to some gene expression that varies slowly and controls the pattern change. The morphogenesis is regulated by combinations of feedback or feedforward regulations, where the upstream feedforward network reads the external morphogen gradient, and generates a pattern used as a boundary condition for the later patterns. The ordering from up to downstream is common in evolution and development, while the successive epochal changes in development and evolution are represented as common bifurcations in dynamical-systems theory, which lead to the evolution-development congruence. Mechanism of exceptional violation of the congruence is also unveiled. Our results provide a new look on developmental stages, punctuated equilibrium, developmental bottlenecks, and evolutionary acquisition of novelty in morphogenesis.

  10. Evolution-development congruence in pattern formation dynamics: Bifurcations in gene expression and regulation of networks structures.

    Science.gov (United States)

    Kohsokabe, Takahiro; Kaneko, Kunihiko

    2016-01-01

    Search for possible relationships between phylogeny and ontogeny is important in evolutionary-developmental biology. Here we uncover such relationships by numerical evolution and unveil their origin in terms of dynamical systems theory. By representing developmental dynamics of spatially located cells with gene expression dynamics with cell-to-cell interaction under external morphogen gradient, gene regulation networks are evolved under mutation and selection with the fitness to approach a prescribed spatial pattern of expressed genes. For most numerical evolution experiments, evolution of pattern over generations and development of pattern by an evolved network exhibit remarkable congruence. Both in the evolution and development pattern changes consist of several epochs where stripes are formed in a short time, while for other temporal regimes, pattern hardly changes. In evolution, these quasi-stationary regimes are generations needed to hit relevant mutations, while in development, they are due to some gene expression that varies slowly and controls the pattern change. The morphogenesis is regulated by combinations of feedback or feedforward regulations, where the upstream feedforward network reads the external morphogen gradient, and generates a pattern used as a boundary condition for the later patterns. The ordering from up to downstream is common in evolution and development, while the successive epochal changes in development and evolution are represented as common bifurcations in dynamical-systems theory, which lead to the evolution-development congruence. Mechanism of exceptional violation of the congruence is also unveiled. Our results provide a new look on developmental stages, punctuated equilibrium, developmental bottlenecks, and evolutionary acquisition of novelty in morphogenesis. PMID:26678220

  11. SES2D user's manual

    International Nuclear Information System (INIS)

    SES2D is an interactive graphics code designed to generate plots of equation of state data from the Los Alamos National Laboratory Group T-4 computer libraries. This manual discusses the capabilities of the code. It describes the prompts and commands and illustrates their use with a sample run

  12. Computational 2D Materials Database

    DEFF Research Database (Denmark)

    Rasmussen, Filip Anselm; Thygesen, Kristian Sommer

    2015-01-01

    , and comparison is made with different density functional theory descriptions. Pitfalls related to the convergence of GW calculations for two-dimensional (2D) materials are discussed together with possible solutions. The monolayer band edge positions relative to vacuum are used to estimate the band alignment...

  13. Nuclear Architecture and Patterns of Molecular Evolution Are Correlated in the Ciliate Chilodonella uncinata.

    Science.gov (United States)

    Maurer-Alcalá, Xyrus X; Katz, Laura A

    2016-01-01

    The relationship between nuclear architecture and patterns of molecular evolution in lineages across the eukaryotic tree of life is not well understood, partly because molecular evolution is traditionally explored as changes in base pairs along a linear sequence without considering the context of nuclear position of chromosomes. The ciliate Chilodonella uncinata is an ideal system to address the relationship between nuclear architecture and patterns of molecular evolution as the somatic macronucleus of this ciliate is composed of a peripheral DNA-rich area (orthomere) and a DNA-poor central region (paramere) to form a "heteromeric" macronucleus. Moreover, because the somatic chromosomes of C. uncinata are highly processed into "gene-sized" chromosomes (i.e., nanochromosomes), we can assess fine-scale relationships between location and sequence evolution. By combining fluorescence microscopy and analyses of transcriptome data from C. uncinata, we find that highly expressed genes have the greatest codon usage bias and are enriched in DNA-poor regions. In contrast, genes with less biased sequences tend to be concentrated in DNA abundant areas, at least during vegetative growth. Our analyses are consistent with recent work in plants and animals where nuclear architecture plays a role in gene expression. At the same time, the unusual localization of nanochromosomes suggests that the highly structured nucleus in C. uncinata may create a "gene bank" that facilitates rapid changes in expression of genes required only in specific life history stages. By using "nonmodel" organisms like C. uncinata, we can explore the universality of eukaryotic features while also providing examples of novel properties (i.e., the presence of a gene bank) that build from these features. PMID:27189988

  14. Spatial pattern of reference evapotranspiration change and its temporal evolution over Southwest China

    Science.gov (United States)

    Sun, Shanlei; Wang, Guojie; Huang, Jin; Mu, Mengyuan; Yan, Guixia; Liu, Chunwei; Gao, Chujie; Li, Xing; Yin, Yixing; Zhang, Fangmin; Zhu, Siguang; Hua, Wenjian

    2016-09-01

    Due to the close relationship of climate change with reference evapotranspiration (ETo), detecting changes in ETo spatial distribution and its temporal evolution at local and regional levels is favorable to comprehensively understand climate change-induced impacts on hydrology and agriculture. In this study, the objective is to identify whether climate change has caused variation of ETo spatial distribution in different analysis periods [i.e., long- (20-year), medium- (10-year), and short-term (5-year)] and to investigate its temporal evolution (namely, when these changes happened) at annual and monthly scales in Southwest China (SWC). First, we estimated ETo values using the United Nations Food and Agriculture Organization (FAO) Penman-Monteith equation, based on historical climate data measured at 269 weather sites during 1973-2012. The analysis of variance (ANOVA) results indicated that the spatial pattern of annual ETo had significantly changed during the past 40 years, particularly in west SWC for the long-term analysis period, and west and southeast SWC in both medium- and short-term periods, which corresponded to the percent area of significant differences which were 21.9, 58.0, and 48.2 %, respectively. For investigating temporal evolution of spatial patterns of annual ETo, Duncan's multiple range test was used, and we found that the most significant changes appeared during 1988-2002 with the significant area of higher than 25.0 %. In addition, for long-, medium-, and short-term analysis periods, the spatial distribution has significantly changed during March, September, November, and December, especially in the corresponding periods of 1988-1997, 1983-1992, 1973-1977, and 1988-2002. All in all, climate change has resulted in significant ETo changes in SWC since the 1970s. Knowledge of climate change-induced spatial distribution of ETo and its temporal evolution would aid in formulating strategies for water resources and agricultural managements.

  15. Excitation of 2D plasmons in Cs/W(110)

    CERN Document Server

    Benemanskaya, G V; Frank-Kamenetskaya, G E

    2001-01-01

    One studied the evolution of surface photoemission spectra for Cs/W(110) system at metastable Cs coatings exceeding monolayer. One showed possibility to observe 2D plasmons by means of threshold photoemission spectroscopy. One detected three photoemission peaks characterized by complicated behavior depending on Cd adsorption dose. The nature of peaks may be related to plasmon photoinduced excitation in quasi-2D Cs clusters, surface Cs plasmon and interface Cs-W plasmon

  16. TPR repeats and ELTR pattern: length variation as a function evolution mechanism.

    Science.gov (United States)

    Yang, Ke-Qian

    2007-12-01

    TPR repeat was originally defined as a 34 amino acid structural repeat (TPR-34). Equal length tandem repeats (ELTR) was proposed to represent the ancestral repeat pattern. Length polymorphism of TPR repeats was analyzed using PATTINPROT, two new versions of TPR repeat of 40 and 42 amino acids were identified. These 'long' TPRs endow new functional capacities to the resulting proteins. A strong correlation between varied lengths and new functions supports the hypothesis that length variation is an underlying mechanism for the function evolution of repeat containing proteins.

  17. Exploring the patterns and evolution of self-organized urban street networks through modeling

    Science.gov (United States)

    Rui, Yikang; Ban, Yifang; Wang, Jiechen; Haas, Jan

    2013-03-01

    As one of the most important subsystems in cities, urban street networks have recently been well studied by using the approach of complex networks. This paper proposes a growing model for self-organized urban street networks. The model involves a competition among new centers with different values of attraction radius and a local optimal principle of both geometrical and topological factors. We find that with the model growth, the local optimization in the connection process and appropriate probability for the loop construction well reflect the evolution strategy in real-world cities. Moreover, different values of attraction radius in centers competition process lead to morphological change in patterns including urban network, polycentric and monocentric structures. The model succeeds in reproducing a large diversity of road network patterns by varying parameters. The similarity between the properties of our model and empirical results implies that a simple universal growth mechanism exists in self-organized cities.

  18. The Repeat Pattern Toolkit (RPT): Analyzing the structure and evolution of the C. elegans genome

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, P.; States, D.J. [Washington Univ., St. Louis, MO (United States)

    1994-12-31

    Over 3.6 million bases of DNA sequence from chromosome III of the C. elegans have been determined. The availability of this extended region of contiguous sequence has allowed us to analyze the nature and prevalence of repetitive sequences in the genome of a eukaryotic organism with a high gene density. We have assembled a Repeat Pattern Toolkit (RPT) to analyze the patterns of repeats occurring in DNA. The tools include identifying significant local alignments (utilizing both two-way and three-way alignments), dividing the set of alignments into connected components (signifying repeat families), computing evolutionary distance between repeat family members, constructing minimum spanning trees from the connected components, and visualizing the evolution of the repeat families. Over 7000 families of repetitive sequences were identified. The size of the families ranged from isolated pairs to over 1600 segments of similar sequence. Approximately 12.3% of the analyzed sequence participates in a repeat element.

  19. Phylogeographic patterns and evolution of the mitochondrial DNA control region in two neotropical cats (Mammalia, felidae).

    Science.gov (United States)

    Eizirik, E; Bonatto, S L; Johnson, W E; Crawshaw, P G; Vié, J C; Brousset, D M; O'Brien, S J; Salzano, F M

    1998-11-01

    The ocelot (Leopardus pardalis) and margay (L. wiedii) are sister-species of Neotropical cats which evolved from a lineage that migrated into South America during the formation of the Panamanian land bridge 3-5 million years ago. Patterns of population genetic divergence of each species were studied by phylogenetic analyses of mitochondrial DNA (mtDNA) control region sequences in individuals sampled across the distribution of these taxa. Abundant genetic diversity and remarkably concordant phylogeographic partitions for both species were observed, identifying parallel geographic regions which likely reflect historical faunal barriers. Inferred aspects of phylogeography, population genetic structure, and demographic history were used to formulate conservation recommendations for these species. In addition, observed patterns of sequence variation provided insight into the molecular evolution of the mtDNA control region in closely related felids. PMID:9797412

  20. Numerical study of IP3-induced Ca2+ spiral pattern evolution

    Institute of Scientific and Technical Information of China (English)

    Tang Jun; Ma Jun; Yi Ming; Jia Ya

    2008-01-01

    The effect of change in concentration of messenger molecule inositol 1,4,5-trisphosphate (IP3) on intracellular Ca2+spiral pattern evolution is studied numerically.The results indicate that when the IP3 concentration decreases from 0.27μM,a physiologically reasonable value,to different values,the spiral centre drifts to the edge of the medium and disappears for a small enough IP3 concentration.The instability of spiral pattern can be understood in terms of excitability-change controlled by the IP3 concentration.On the other hand,when the IP3 concentration increases from 0.27μM,a homogeneous area with a high Ca2+ concentration emerges and competes with the spiral pattern.A high enough IP3 concentration can lead the homogeneous area to occupy the whole medium.The instability of spiral pattern is ascribed to the change in stability of a stationary state with a high Ca2+ concentration.

  1. ChIP-Seq-Annotated Heliconius erato Genome Highlights Patterns of cis-Regulatory Evolution in Lepidoptera.

    Science.gov (United States)

    Lewis, James J; van der Burg, Karin R L; Mazo-Vargas, Anyi; Reed, Robert D

    2016-09-13

    Uncovering phylogenetic patterns of cis-regulatory evolution remains a fundamental goal for evolutionary and developmental biology. Here, we characterize the evolution of regulatory loci in butterflies and moths using chromatin immunoprecipitation sequencing (ChIP-seq) annotation of regulatory elements across three stages of head development. In the process we provide a high-quality, functionally annotated genome assembly for the butterfly, Heliconius erato. Comparing cis-regulatory element conservation across six lepidopteran genomes, we find that regulatory sequences evolve at a pace similar to that of protein-coding regions. We also observe that elements active at multiple developmental stages are markedly more conserved than elements with stage-specific activity. Surprisingly, we also find that stage-specific proximal and distal regulatory elements evolve at nearly identical rates. Our study provides a benchmark for genome-wide patterns of regulatory element evolution in insects, and it shows that developmental timing of activity strongly predicts patterns of regulatory sequence evolution.

  2. Aero Fighter - 2D Gaming

    CERN Document Server

    Ahmed, Zeeshan

    2010-01-01

    Designing and developing quality based computer game is always a challenging task for developers. In this paper I briefly discuss aero fighting war game based on simple 2D gaming concepts and developed in C & C++ programming languages, using old bitmapping concepts. Going into the details of the game development, I discuss the designed strategies, flow of game and implemented prototype version of game, especially for beginners of game programming.

  3. Holocene denudation pattern across the South-Eastern Australian Escarpment and implications for its evolution

    Science.gov (United States)

    Godard, Vincent; Dosseto, Anthony; Bellier, Olivier; Bourlès, Didier; Fleury, Jules; Aster Team

    2016-04-01

    Developing a process based understanding of continental relief evolution requires to quantify rates of denudation and to compare their distribution with the evolution of geomorphic parameters. The analysis of denudation and exhumation spatial patterns based from cosmogenic nuclides and low temperature thermochronology are routinely used to document the processes associated with the geomorphic evolution of continental relief over various timescales. Passive margin escarpments are among some of the most salient continental geomorphic features outside of orogenic areas. Their evolution have been studied intensively over the long-term (several Ma to tens of Ma), using for example low-temperature thermochronology. However, datasets documenting their shorter-term (1-10 ka) dynamics are scarcer, and only a limited number of case studies have used quantitative techniques such as cosmogenic nuclides to document the denudation pattern across such escarpments. The South Eastern Australian Escarpment is such a place where cosmogenic nuclides have been intensively used over the last two decades to constrain processes of landscape evolution over short wavelength, with, for example the calibration of the soil production function. Such existing data and constraints provide an ideal setting to carry on further long-wavelength exploration of the dynamics of the whole escarpment. We have sampled 17 catchments across the South Eastern Australian Escarpment, starting from the coastal plain and moving westward up to the low relief plateau surface. The observed landscape denudation rates are 10-20 mm/ka in the coastal area and progressively increases up to ~60 mm/ka toward the edge of the escarpment. In the low-relief areas located west of the continental drainage divide denudation rates fall back to 10-20 mm/ka. This nearly four-fold contrast in denudation across the divide is characteristic of a major disequilibrium in the dynamics of the river network associated with a progressive

  4. DESIGN METHODOLOGY OF NETWORKED SOFTWARE EVOLUTION GROWTH BASED ON SOFTWARE PATTERNS

    Institute of Scientific and Technical Information of China (English)

    Keqing HE; Rong PENG; Jing LIU; Fei HE; Peng LIANG; Bing LI

    2006-01-01

    Recently, some new characteristics of complex networks attract the attentions of scientists in different fields, and lead to many kinds of emerging research directions. So far, most of the research work has been limited in discovery of complex network characteristics by structure analysis in large-scale software systems. This paper presents the theoretical basis, design method, algorithms and experiment results of the research. It firstly emphasizes the significance of design method of evolution growth for network topology of Object Oriented (OO) software systems, and argues that the selection and modulation of network models with various topology characteristics will bring un-ignorable effect on the process of design and implementation of OO software systems. Then we analyze the similar discipline of "negation of negation and compromise" between the evolution of network models with different topology characteristics and the development of software modelling methods. According to the analysis of the growth features of software patterns, we propose an object-oriented software network evolution growth method and its algorithms in succession. In addition, we also propose the parameter systems for Oosoftware system metrics based on complex network theory. Based on these parameter systems, it can analyze the features of various nodes, links and local-world, modulate the network topology and guide the software metrics. All these can be helpful to the detailed design, implementation and performance analysis. Finally, we focus on the application of the evolution algorithms and demonstrate it by a case study.Comparing the results from our early experiments with methodologies in empirical software engineering, we believe that the proposed software engineering design method is a computational software engineering approach based on complex network theory. We argue that this method should be greatly beneficial for the design, implementation, modulation and metrics of

  5. Multienzyme Inkjet Printed 2D Arrays.

    Science.gov (United States)

    Gdor, Efrat; Shemesh, Shay; Magdassi, Shlomo; Mandler, Daniel

    2015-08-19

    The use of printing to produce 2D arrays is well established, and should be relatively facile to adapt for the purpose of printing biomaterials; however, very few studies have been published using enzyme solutions as inks. Among the printing technologies, inkjet printing is highly suitable for printing biomaterials and specifically enzymes, as it offers many advantages. Formulation of the inkjet inks is relatively simple and can be adjusted to a variety of biomaterials, while providing nonharmful environment to the enzymes. Here we demonstrate the applicability of inkjet printing for patterning multiple enzymes in a predefined array in a very straightforward, noncontact method. Specifically, various arrays of the enzymes glucose oxidase (GOx), invertase (INV) and horseradish peroxidase (HP) were printed on aminated glass surfaces, followed by immobilization using glutardialdehyde after printing. Scanning electrochemical microscopy (SECM) was used for imaging the printed patterns and to ascertain the enzyme activity. The successful formation of 2D arrays consisting of enzymes was explored as a means of developing the first surface confined enzyme based logic gates. Principally, XOR and AND gates, each consisting of two enzymes as the Boolean operators, were assembled, and their operation was studied by SECM. PMID:26214072

  6. Wing pattern evolution and the origins of mimicry among North American admiral butterflies (Nymphalidae: Limenitis).

    Science.gov (United States)

    Mullen, Sean P

    2006-06-01

    The evolution of wing pattern diversity in butterflies has emerged as a model system for understanding the origins and maintenance of adaptive phenotypic novelty. Admiral butterflies (genus Limenitis) are an attractive system for studying wing pattern diversity because mimicry is common among the North American species and hybrid zones occur wherever mimetic and non-mimetic wing pattern races meet. However, the utility of this system has been limited because the evolutionary relationships among these butterflies remain unclear. Here I present a robust species-level phylogeny of Limenitis based on 1911 bp of two mitochondrial genes (COI and COII) and 904 bp of EF1-alpha for all five of the Nearctic species/wing pattern races, the majority of the Palearctic species, and three outgroup genera; Athyma, Moduza (Limenitidini), and Neptis (Limenitidinae: Neptini). Maximum-likelihood and Bayesian analyses indicate that the North American species are a well-supported, monophyletic lineage that is most closely related to the widespread, Palearctic, Poplar admiral (L. populi). Within North America, the Viceroy (L. archippus) is the basal lineage while the relationships among the remaining species are not well resolved. A combined maximum-likelihood analysis, however, indicates that the two western North America species (L. lorquini and L. weidemeyerii) are sister taxa and closely related to the wing pattern subspecies of the polytypic Limenitis arthemis species complex. These results are consistent with (1) an ancestral host-shift to Salicaceae by the common ancestor of the Poplar admiral and the Nearctic admiral lineage, (2) a single colonization of the Nearctic, and (3) a subsequent radiation of the North American forms leading to at least three independent origins of mimicry.

  7. R2d2 Drives Selfish Sweeps in the House Mouse.

    Science.gov (United States)

    Didion, John P; Morgan, Andrew P; Yadgary, Liran; Bell, Timothy A; McMullan, Rachel C; Ortiz de Solorzano, Lydia; Britton-Davidian, Janice; Bult, Carol J; Campbell, Karl J; Castiglia, Riccardo; Ching, Yung-Hao; Chunco, Amanda J; Crowley, James J; Chesler, Elissa J; Förster, Daniel W; French, John E; Gabriel, Sofia I; Gatti, Daniel M; Garland, Theodore; Giagia-Athanasopoulou, Eva B; Giménez, Mabel D; Grize, Sofia A; Gündüz, İslam; Holmes, Andrew; Hauffe, Heidi C; Herman, Jeremy S; Holt, James M; Hua, Kunjie; Jolley, Wesley J; Lindholm, Anna K; López-Fuster, María J; Mitsainas, George; da Luz Mathias, Maria; McMillan, Leonard; Ramalhinho, Maria da Graça Morgado; Rehermann, Barbara; Rosshart, Stephan P; Searle, Jeremy B; Shiao, Meng-Shin; Solano, Emanuela; Svenson, Karen L; Thomas-Laemont, Patricia; Threadgill, David W; Ventura, Jacint; Weinstock, George M; Pomp, Daniel; Churchill, Gary A; Pardo-Manuel de Villena, Fernando

    2016-06-01

    A selective sweep is the result of strong positive selection driving newly occurring or standing genetic variants to fixation, and can dramatically alter the pattern and distribution of allelic diversity in a population. Population-level sequencing data have enabled discoveries of selective sweeps associated with genes involved in recent adaptations in many species. In contrast, much debate but little evidence addresses whether "selfish" genes are capable of fixation-thereby leaving signatures identical to classical selective sweeps-despite being neutral or deleterious to organismal fitness. We previously described R2d2, a large copy-number variant that causes nonrandom segregation of mouse Chromosome 2 in females due to meiotic drive. Here we show population-genetic data consistent with a selfish sweep driven by alleles of R2d2 with high copy number (R2d2(HC)) in natural populations. We replicate this finding in multiple closed breeding populations from six outbred backgrounds segregating for R2d2 alleles. We find that R2d2(HC) rapidly increases in frequency, and in most cases becomes fixed in significantly fewer generations than can be explained by genetic drift. R2d2(HC) is also associated with significantly reduced litter sizes in heterozygous mothers, making it a true selfish allele. Our data provide direct evidence of populations actively undergoing selfish sweeps, and demonstrate that meiotic drive can rapidly alter the genomic landscape in favor of mutations with neutral or even negative effects on overall Darwinian fitness. Further study will reveal the incidence of selfish sweeps, and will elucidate the relative contributions of selfish genes, adaptation and genetic drift to evolution. PMID:26882987

  8. Patterns of evolution of MHC class II genes of crows (Corvus suggest trans-species polymorphism

    Directory of Open Access Journals (Sweden)

    John A. Eimes

    2015-03-01

    Full Text Available A distinguishing characteristic of genes that code for the major histocompatibility complex (MHC is that alleles often share more similarity between, rather than within species. There are two likely mechanisms that can explain this pattern: convergent evolution and trans-species polymorphism (TSP, in which ancient allelic lineages are maintained by balancing selection and retained by descendant species. Distinguishing between these two mechanisms has major implications in how we view adaptation of immune genes. In this study we analyzed exon 2 of the MHC class IIB in three passerine bird species in the genus Corvus: jungle crows (Corvus macrorhynchos japonensis American crows (C. brachyrhynchos and carrion crows (C. corone orientalis. Carrion crows and American crows are recently diverged, but allopatric, sister species, whereas carrion crows and jungle crows are more distantly related but sympatric species, and possibly share pathogens linked to MHC IIB polymorphisms. These patterns of evolutionary divergence and current geographic ranges enabled us to test for trans-species polymorphism and convergent evolution of the MHC IIB in crows. Phylogenetic reconstructions of MHC IIB sequences revealed several well supported interspecific clusters containing all three species, and there was no biased clustering of variants among the sympatric carrion crows and jungle crows. The topologies of phylogenetic trees constructed from putatively selected sites were remarkably different than those constructed from putatively neutral sites. In addition, trees constructed using non-synonymous substitutions from a continuous fragment of exon 2 had more, and generally more inclusive, supported interspecific MHC IIB variant clusters than those constructed from the same fragment using synonymous substitutions. These phylogenetic patterns suggest that recombination, especially gene conversion, has partially erased the signal of allelic ancestry in these species. While

  9. Flow pattern and lift evolution of hydrofoil with control of electro-magnetic forces

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The initial responses and evolutions of the flow pattern and lift coefficient of a hydrofoil under the action of electro-magnetic (Lorentz) force have been studied experimentally and numerically, and trace particle methods are employed for them. With the introduction of BVF (boundary vortex flux), the quantitative relation among Lorentz forces, BVF and lifts is deduced. The influences of flow patterns on the hydrofoil lift coefficient have been discussed based on the BVF distribution, and the flow control mechanism of Lorentz force for a hydrofoil has been elucidated. Our results show that the flow pattern and lift of the hydrofoil vary periodically without any force. However, with the action of streamwise Lorentz forces, the separation point on the hydrofoil surface moves backward with a certain velocity, which makes the flow field steady finally. The streamwise Lorentz force raises the foil lift due to the increase of BVF intensity. On the other hand, Lorentz force also increases the hydrofoil surface pressure, which makes the lift decrease. However, the factor leading to the lift enhancement is determinant, therefore, the Lorentz force on the suction side can increase the lift, and the stronger the Lorentz force, the larger the lift enhancement. Our results also show that the localized Lorentz force can also both suppress the flow separation and increase the hydrofoil lift coefficient, furthermore, the Lorentz force located on the tail acts better than that located on the front.

  10. 2D-animaatiotuotannon optimointi

    OpenAIRE

    Saturo, Reetta

    2015-01-01

    Tämän opinnäytetyön tavoitteena on tutkia 2D-animaatiotuotannon optimoinnin mahdollisuuksia tiukan tuotantoaikataulun vaatimuksissa. Tutkielmassa tarkastellaan kahta asiakasprojektia, jotka on toteutettu pienellä tuotantotiimillä. Työkaluna animaatioissa on käytetty pääosin Adoben After Effects -ohjelmistoa. Tutkielman alussa esitellään animaatiotuotannot, joiden tuloksena syntyi kaksi lyhyttä mainoselokuvaa. Sen jälkeen käydään läpi animaatioelokuvan tuotantoprosessia vaiheittain ja tark...

  11. Head First 2D Geometry

    CERN Document Server

    Fallow), Stray

    2009-01-01

    Having trouble with geometry? Do Pi, The Pythagorean Theorem, and angle calculations just make your head spin? Relax. With Head First 2D Geometry, you'll master everything from triangles, quads and polygons to the time-saving secrets of similar and congruent angles -- and it'll be quick, painless, and fun. Through entertaining stories and practical examples from the world around you, this book takes you beyond boring problems. You'll actually use what you learn to make real-life decisions, like using angles and parallel lines to crack a mysterious CSI case. Put geometry to work for you, and

  12. Patterns of evolution and host gene mimicry in influenza and other RNA viruses.

    Directory of Open Access Journals (Sweden)

    Benjamin D Greenbaum

    2008-06-01

    Full Text Available It is well known that the dinucleotide CpG is under-represented in the genomic DNA of many vertebrates. This is commonly thought to be due to the methylation of cytosine residues in this dinucleotide and the corresponding high rate of deamination of 5-methycytosine, which lowers the frequency of this dinucleotide in DNA. Surprisingly, many single-stranded RNA viruses that replicate in these vertebrate hosts also have a very low presence of CpG dinucleotides in their genomes. Viruses are obligate intracellular parasites and the evolution of a virus is inexorably linked to the nature and fate of its host. One therefore expects that virus and host genomes should have common features. In this work, we compare evolutionary patterns in the genomes of ssRNA viruses and their hosts. In particular, we have analyzed dinucleotide patterns and found that the same patterns are pervasively over- or under-represented in many RNA viruses and their hosts suggesting that many RNA viruses evolve by mimicking some of the features of their host's genes (DNA and likely also their corresponding mRNAs. When a virus crosses a species barrier into a different host, the pressure to replicate, survive and adapt, leaves a footprint in dinucleotide frequencies. For instance, since human genes seem to be under higher pressure to eliminate CpG dinucleotide motifs than avian genes, this pressure might be reflected in the genomes of human viruses (DNA and RNA viruses when compared to those of the same viruses replicating in avian hosts. To test this idea we have analyzed the evolution of the influenza virus since 1918. We find that the influenza A virus, which originated from an avian reservoir and has been replicating in humans over many generations, evolves in a direction strongly selected to reduce the frequency of CpG dinucleotides in its genome. Consistent with this observation, we find that the influenza B virus, which has spent much more time in the human population, has

  13. 2D Cooling of Magnetized Neutron Stars

    CERN Document Server

    Aguilera, Deborah N; Miralles, Juan A

    2007-01-01

    Context: Many thermally emitting isolated neutron stars have magnetic fields larger than 10^{13}G. A realistic cooling model should be reconsidered including the presence of high magnetic fields. Aims: We investigate the effects of anisotropic temperature distribution and Joule heating on the cooling of magnetized neutron stars. Methods: The 2D heat transfer equation with anisotropic thermal conductivity tensor and including all relevant neutrino emission processes is solved for realistic models of the neutron star interior and crust. Results: The presence of the magnetic field affects significantly the thermal surface distribution and the cooling history during both, the early neutrino cooling era and the late photon cooling era. Conclusions: There is a huge effect of the Joule heating on the thermal evolution of strongly magnetized neutron stars. Magnetic fields and Joule heating play a key role in maintaining magnetars warm for a long time. Moreover, this effect is also important for intermediate field neu...

  14. Identification of Tumor Evolution Patterns by Means of Inductive Logic Programming

    Institute of Scientific and Technical Information of China (English)

    Vitoantonio Bevilacqua; Patrizia Chiarappa; Giuseppe Mastronardi; Filippo Menolascina; Angelo Paradiso; Stefania Tommasi

    2008-01-01

    In considering key events of genomic disorders in the development and progression of cancer, the correlation between genomic instability and carcinogenesis is currently under investigation. In this work, we propose an inductive logic programming approach to the problem of modeling evolution patterns for breast cancer. Using this approach, it is possible to extract fingerprints of stages of the disease that can be used in order to develop and deliver the most adequate therapies to patients. Furthermore, such a model can help physicians and biologists in the elucidation of molecular dynamics underlying the aberrations-waterfall model behind carcinogenesis. By showing results obtained on a real-world dataset, we try to give some hints about further approach to the knowledge-driven validations of such hypotheses.

  15. Distinct patterns in the regulation and evolution of human cancer genes.

    Science.gov (United States)

    Furney, Simon J; Madden, Stephen F; Kisiel, Tomasz A; Higgins, Desmond G; Lopez-Bigas, Nuria

    2008-01-01

    Understanding the mechanism of regulation of cancer genes and the constraints on their coding sequences is of fundamental importance in understanding the process of tumour development. Here we test the hypothesis that tumour suppressor genes and proto-oncogenes, due to their involvement in tumourigenesis, have distinct patterns of regulation and coding selective constraints compared to non-cancer genes. Indeed, we found significantly greater conservation in the promoter regions of proto-oncogenes, suggesting that these genes are more tightly regulated, i.e. they are more likely to contain a higher density of cis-regulatory elements. Furthermore, proto-oncogenes appear to be preferentially targeted by microRNAs and have longer 3' UTRs. In addition, proto-oncogene evolution appears to be highly constrained, compared to tumour suppressor genes and non-cancer genes. A number of these trends are confirmed in breast and colon cancer gene sets recently identified by mutational screening.

  16. The first 50Myr of dinosaur evolution: macroevolutionary pattern and morphological disparity.

    Science.gov (United States)

    Brusatte, Stephen L; Benton, Michael J; Ruta, Marcello; Lloyd, Graeme T

    2008-12-23

    The evolutionary radiation of dinosaurs in the Late Triassic and Early Jurassic was a pivotal event in the Earth's history but is poorly understood, as previous studies have focused on vague driving mechanisms and have not untangled different macroevolutionary components (origination, diversity, abundance and disparity). We calculate the morphological disparity (morphospace occupation) of dinosaurs throughout the Late Triassic and Early Jurassic and present new measures of taxonomic diversity. Crurotarsan archosaurs, the primary dinosaur 'competitors', were significantly more disparate than dinosaurs throughout the Triassic, but underwent a devastating extinction at the Triassic-Jurassic boundary. However, dinosaur disparity showed only a slight non-significant increase after this event, arguing against the hypothesis of ecological release-driven morphospace expansion in the Early Jurassic. Instead, the main jump in dinosaur disparity occurred between the Carnian and Norian stages of the Triassic. Conversely, dinosaur diversity shows a steady increase over this time, and measures of diversification and faunal abundance indicate that the Early Jurassic was a key episode in dinosaur evolution. Thus, different aspects of the dinosaur radiation (diversity, disparity and abundance) were decoupled, and the overall macroevolutionary pattern of the first 50Myr of dinosaur evolution is more complex than often considered.

  17. Inferring directions of evolution from patterns of variation: the legacy of Sergei Meyen.

    Science.gov (United States)

    Sharov, Alexei A; Igamberdiev, Abir U

    2014-09-01

    In the era of the extended evolutionary synthesis, which no longer considers natural selection as the only leading factor of evolution, it is meaningful to revisit the legacy of biologists who discussed the role of alternative factors. Here we analyze the evolutionary views of Sergei Meyen (1935-1987), a paleobotanist who argued that the theory of evolution should incorporate a "nomothetical" approach which infers the laws of morphogenesis (i.e., form generation) from the observed patterns of variation in living organisms and in the fossil records. Meyen developed a theory of "repeated polymorphic sets" (RPSs), which he applied consistently to describe inter-organism variation in populations, intra-organism variation of metameric organs, variation of abnormalities, heterotopy, changes during embryo development, and inter-species variation within evolutionary lineages. The notion of RPS assumes the active nature of organisms that possess hidden morphogenic and behavioral capacities. Meyen's theory is compatible with Darwin's natural selection; however, Meyen emphasized the importance of other forms of selection (e.g., selection of developmental trajectories, habitats, and behaviors) in choosing specific elements from the RPS. Finally, Meyen developed a new typological concept of time, where time represents variability (i.e., change) of real objects such as living organisms or geological formations.

  18. Amphioxus and lamprey AP-2 genes: implications for neural crest evolution and migration patterns

    Science.gov (United States)

    Meulemans, Daniel; Bronner-Fraser, Marianne

    2002-01-01

    The neural crest is a uniquely vertebrate cell type present in the most basal vertebrates, but not in cephalochordates. We have studied differences in regulation of the neural crest marker AP-2 across two evolutionary transitions: invertebrate to vertebrate, and agnathan to gnathostome. Isolation and comparison of amphioxus, lamprey and axolotl AP-2 reveals its extensive expansion in the vertebrate dorsal neural tube and pharyngeal arches, implying co-option of AP-2 genes by neural crest cells early in vertebrate evolution. Expression in non-neural ectoderm is a conserved feature in amphioxus and vertebrates, suggesting an ancient role for AP-2 genes in this tissue. There is also common expression in subsets of ventrolateral neurons in the anterior neural tube, consistent with a primitive role in brain development. Comparison of AP-2 expression in axolotl and lamprey suggests an elaboration of cranial neural crest patterning in gnathostomes. However, migration of AP-2-expressing neural crest cells medial to the pharyngeal arch mesoderm appears to be a primitive feature retained in all vertebrates. Because AP-2 has essential roles in cranial neural crest differentiation and proliferation, the co-option of AP-2 by neural crest cells in the vertebrate lineage was a potentially crucial event in vertebrate evolution.

  19. Conserved phenotypic variation patterns, evolution along lines of least resistance, and departure due to selection in fossil rodents.

    Science.gov (United States)

    Renaud, Sabrina; Auffray, Jean-Christophe; Michaux, Jacques

    2006-08-01

    Within a group of organisms, some morphologies are more readily generated than others due to internal developmental constraints. Such constraints can channel evolutionary changes into directions corresponding to the greatest intraspecific variation. Long-term evolutionary outputs, however, depend on the stability of these intraspecific patterns of variation over time and from the interplay between internal constraints and selective regimes. To address these questions, the relationship between the structure of phenotypic variance covariance matrices and direction of morphological evolution was investigated using teeth of fossil rodents. One lineage considered here leads to Stephanomys, a highly specialized genus characterized by a dental pattern supposedly favoring grass eating. Stephanomys evolved in the context of directional selection related to the climatic trend of global cooling causing an increasing proportion of grasslands in southwestern Europe. The initial divergence (up to approximately 6.5 mya) was channeled along the direction of greatest intraspecific variation, whereas after 6.5 mya, morphological evolution departed from the direction favored by internal constraints. This departure from the "lines of least resistance" was likely the consequence of an environmental degradation causing a selective gradient strong enough to overwhelm the constraints to phenotypic evolution. However, in a context of stabilizing selection, these constraints actually channel evolution, as exemplified by the lineage of Apodemus. This lineage retained a primitive diet and dental pattern over the last 10 myr. Limited morphological changes occurred nevertheless in accordance with the main patterns of intraspecific variation. The importance of these lines of least resistance directing long-term morphological evolution may explain parallel evolution of some dental patterns in murine evolution.

  20. Linking pattern to process in cultural evolution: explaining material culture diversity among the Northern Khanty of Northwest Siberia

    OpenAIRE

    Jordan, P.

    2009-01-01

    Book description: This volume offers an integrative approach to the application of evolutionary theory in studies of cultural transmission and social evolution and reveals the enormous range of ways in which Darwinian ideas can lead to productive empirical research, the touchstone of any worthwhile theoretical perspective. While many recent works on cultural evolution adopt a specific theoretical framework, such as dual inheritance theory or human behavioral ecology, Pattern and Process in Cu...

  1. Experimental Evolution under Fluctuating Thermal Conditions Does Not Reproduce Patterns of Adaptive Clinal Differentiation in Drosophila melanogaster.

    Science.gov (United States)

    Kellermann, Vanessa; Hoffmann, Ary A; Kristensen, Torsten Nygaard; Moghadam, Neda Nasiri; Loeschcke, Volker

    2015-11-01

    Experimental evolution can be a useful tool for testing the impact of environmental factors on adaptive changes in populations, and this approach is being increasingly used to understand the potential for evolutionary responses in populations under changing climates. However, selective factors will often be more complex in natural populations than in laboratory environments and produce different patterns of adaptive differentiation. Here we test the ability of laboratory experimental evolution under different temperature cycles to reproduce well-known patterns of clinal variation in Drosophila melanogaster. Six fluctuating thermal regimes mimicking the natural temperature conditions along the east coast of Australia were initiated. Contrary to expectations, on the basis of field patterns there was no evidence for adaptation to thermal regimes as reflected by changes in cold and heat resistance after 1-3 years of laboratory natural selection. While laboratory evolution led to changes in starvation resistance, development time, and body size, patterns were not consistent with those seen in natural populations. These findings highlight the complexity of factors affecting trait evolution in natural populations and indicate that caution is required when inferring likely evolutionary responses from the outcome of experimental evolution studies. PMID:26655772

  2. 2D SIMPLIFIED SERVO VALVE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented.The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool.A criterion for stability is derived from the linear analysis of the valve.Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response.It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage.Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.

  3. Personalized 2D color maps

    KAUST Repository

    Waldin, Nicholas

    2016-06-24

    2D color maps are often used to visually encode complex data characteristics such as heat or height. The comprehension of color maps in visualization is affected by the display (e.g., a monitor) and the perceptual abilities of the viewer. In this paper we present a novel method to measure a user\\'s ability to distinguish colors of a two-dimensional color map on a given monitor. We show how to adapt the color map to the user and display to optimally compensate for the measured deficiencies. Furthermore, we improve user acceptance of the calibration procedure by transforming the calibration into a game. The user has to sort colors along a line in a 3D color space in a competitive fashion. The errors the user makes in sorting these lines are used to adapt the color map to his perceptual capabilities.

  4. Molecular evolution of rbcL in three gymnosperm families: identifying adaptive and coevolutionary patterns

    LENUS (Irish Health Repository)

    Sen, Lin

    2011-06-03

    mutations put forward the conclusion that this evolutionary scenario has been possible through a complex interplay between adaptive mutations, often structurally destabilizing, and compensatory mutations. Our results unearth patterns of evolution that have likely optimized the Rubisco activity and uncover mutational dynamics useful in the molecular engineering of enzymatic activities. Reviewers This article was reviewed by Prof. Christian Blouin (nominated by Dr W Ford Doolittle), Dr Endre Barta (nominated by Dr Sandor Pongor), and Dr Nicolas Galtier.

  5. Flow pattern and lift evolution of hydrofoil with control of electro-magnetic forces

    Institute of Scientific and Technical Information of China (English)

    CHEN YaoHui; FAN BaoChun; CHEN ZhiHua; LI HongZhi

    2009-01-01

    The Initial responses and evolutions of the flow pattern and lift coefficient of a hydrofoil under the ac-tion of electro-magnetic (Lorentz) force have been studied experimentally and numerically,and trace particle methods are employed for them.With the introduction of BVF (boundary vortex flux),the quantitative relation among Lorentz forces,BVF and lifts is deduced.The influences of flow patterns on the hydrofoil lift coefficient have been discussed based on the BVF distribution,and the flow control mechanism of Lorentz force for a hydrofoil has been elucidated.Our results show that the flow pattern and lift of the hydrofoil vary periodically without any force.However,with the action of streamwise Lorentz forces,the separation point on the hydrofoil surface moves backward with a certain velocity,which makes the flow field steady finally.The streamwise Lorentz force raises the foil lift due to the Increase of BVF intensity.On the other hand,Lorentz force also increases the hydrofoil surface pres-sure,which makes the lift decrease.However,the factor leading to the lift enhancement is determinant,therefore,the Lorentz force on the suction side can increase the lift,and the stronger the Lorentz force,the larger the lift enhancement.Our results also show that the localized Lorentz force can also both suppress the flow separation and increase the hydrofoil lift coefficient,furthermore,the Lorentz force located on the tail acts better than that located on the front.

  6. Dynamical patterning modules: physico-genetic determinants of morphological development and evolution

    Science.gov (United States)

    Newman, Stuart A.; Bhat, Ramray

    2008-03-01

    The shapes and forms of multicellular organisms arise by the generation of new cell states and types and changes in the numbers and rearrangements of the various kinds of cells. While morphogenesis and pattern formation in all animal species are widely recognized to be mediated by the gene products of an evolutionarily conserved 'developmental-genetic toolkit', the link between these molecular players and the physics underlying these processes has been generally ignored. This paper introduces the concept of 'dynamical patterning modules' (DPMs), units consisting of one or more products of the 'toolkit' genes that mobilize physical processes characteristic of chemically and mechanically excitable meso- to macroscopic systems such as cell aggregates: cohesion, viscoelasticity, diffusion, spatiotemporal heterogeneity based on lateral inhibition and multistable and oscillatory dynamics. We suggest that ancient toolkit gene products, most predating the emergence of multicellularity, assumed novel morphogenetic functions due to change in the scale and context inherent to multicellularity. We show that DPMs, acting individually and in concert with each other, constitute a 'pattern language' capable of generating all metazoan body plans and organ forms. The physical dimension of developmental causation implies that multicellular forms during the explosive radiation of animal body plans in the middle Cambrian, approximately 530 million years ago, could have explored an extensive morphospace without concomitant genotypic change or selection for adaptation. The morphologically plastic body plans and organ forms generated by DPMs, and their ontogenetic trajectories, would subsequently have been stabilized and consolidated by natural selection and genetic drift. This perspective also solves the apparent 'molecular homology-analogy paradox', whereby widely divergent modern animal types utilize the same molecular toolkit during development by proposing, in contrast to the Neo

  7. [Spatial pattern evolution of carbon emission intensity from energy consumption in China].

    Science.gov (United States)

    Zhao, Yun-Tai; Huang, Xian-Jin; Zhong, Tai-Yang; Peng, Jia-Wen

    2011-11-01

    Using Theil index and spatial autocorrelation analysis methods, the characteristics, regional disparity and spatial pattern evolution of carbon emission intensity from energy consumption were analyzed on national, regional and provincial level from 1999 to 2007 in China. The results indicate that: (1) total energy carbon emission in China has increased from 0.91Gt in 1999 to 1.83Gt in 2007, while carbon emission intensity has decreased from 0.83 t x (10(4) yuan) (-1) to 0.79 t x (10(4) yuan) (-1); (2) carbon emission intensity of eight major economic blocks showed the trend of three-level differentiation, with that of northeast regions, the middle reaches of Yellow River regions and northwest regions above 1.0 t x (10(4) yuan)(-1); northern coastal regions, the middle reaches of Yangtze River regions and southwest regions 0.7-1.0 t x (10(4) yuan) (-1); eastern and northern regions 0.32-0.51 t x (10(4) yuan) (-1); (3) Theil index analysis indicates that the within-region carbon emission intensities were similar, and the expanding total disparity of carbon emission intensity was primarily due to between-region inequalities. (4) spatial autocorrelation analysis shows that Global Moran's I has increased from 0.19 to 0.25, indicating that there were positive spatial correlations among provincial regions in China, and regions of similar carbon emission intensity agglomerated in space. The "cold spot" areas of carbon emission intensity were relatively stable, while the "hot spot" areas has gradually shifted from northwest regions to the middle reaches of Yellow River regions and northeast regions. (5) spatial disparity of carbon emission intensity is closely related to factors such as regional resources endowment, economic development, industrial structure and energy utilization efficiency. The study of regional disparity and spatial autocorrelation provides insight into spatial heterogeneity and spatial pattern evolution of carbon emission intensity in China, and also

  8. [Prediction method of rural landscape pattern evolution based on life cycle: a case study of Jinjing Town, Hunan Province, China].

    Science.gov (United States)

    Ji, Xiang; Liu, Li-Ming; Li, Hong-Qing

    2014-11-01

    Taking Jinjing Town in Dongting Lake area as a case, this paper analyzed the evolution of rural landscape patterns by means of life cycle theory, simulated the evolution cycle curve, and calculated its evolution period, then combining CA-Markov model, a complete prediction model was built based on the rule of rural landscape change. The results showed that rural settlement and paddy landscapes of Jinjing Town would change most in 2020, with the rural settlement landscape increased to 1194.01 hm2 and paddy landscape greatly reduced to 3090.24 hm2. The quantitative and spatial prediction accuracies of the model were up to 99.3% and 96.4%, respectively, being more explicit than single CA-Markov model. The prediction model of rural landscape patterns change proposed in this paper would be helpful for rural landscape planning in future.

  9. Learn Unity for 2D game development

    CERN Document Server

    Thorn, Alan

    2013-01-01

    The only Unity book specifically covering 2D game development Written by Alan Thorn, experience game developer and author of seven books on game programming Hands-on examples of all major aspects of 2D game development using Unity

  10. 2D-ACAR investigations of PPT aramid fibres

    International Nuclear Information System (INIS)

    2D-ACAR spectra of PPT (poly(p-phenylene terephthalamide)) fibres which contain structural elongated open spaces in the crystallographic unit cell show a p-Ps peak with an elliptical cross-section and side lobes. Peak broadening suggests dimensions of ∝14-17 by 7-9 A for the open spaces and indicates some penetration of Ps into the interlayer spacing. The side lobes can be related to projected reciprocal lattice points and indicate Ps delocalization. 2D-ACAR has also been used to study the evolution of water release from the open spaces. (orig.)

  11. Patterns of Protein Evolution in Cytochrome c Oxidase 1 (COI from the Class Arachnida.

    Directory of Open Access Journals (Sweden)

    Monica R Young

    Full Text Available Because sequence information is now available for the 648bp barcode region of cytochrome c oxidase 1 (COI from more than 400,000 animal species, this gene segment can be used to probe patterns of mitochondrial evolution. The present study examines levels of amino acid substitution and the frequency of indels in COI from 4177 species of arachnids, including representatives from all 16 orders and 43% of its families (267/625. It examines divergences at three taxonomic levels-among members of each order to an outgroup, among families in each order and among BINs, a species proxy, in each family. Order Distances vary fourfold (0.10-0.39, while the mean of the Family Distances for the ten orders ranges fivefold (0.07-0.35. BIN Distances show great variation, ranging from 0.01 or less in 12 families to more than 0.25 in eight families. Patterns of amino acid substitution in COI are generally congruent with previously reported variation in nucleotide substitution rates in arachnids, but provide some new insights, such as clear rate acceleration in the Opiliones. By revealing a strong association between elevated rates of nucleotide and amino acid substitution, this study builds evidence for the selective importance of the rate variation among arachnid lineages. Moreover, it establishes that groups whose COI genes have elevated levels of amino acid substitution also regularly possess indels, a dramatic form of protein reconfiguration. Overall, this study suggests that the mitochondrial genome of some arachnid groups is dynamic with high rates of amino acid substitution and frequent indels, while it is 'locked down' in others. Dynamic genomes are most prevalent in arachnids with short generation times, but the possible impact of breeding system deserves investigation since many of the rapidly evolving lineages reproduce by haplodiploidy, a mode of reproduction absent in 'locked down' taxa.

  12. Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes.

    Directory of Open Access Journals (Sweden)

    Charlie J Underwood

    Full Text Available Shark and ray (elasmobranch dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays, hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files, presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as

  13. Development and evolution of dentition pattern and tooth order in the skates and rays (batoidea; chondrichthyes).

    Science.gov (United States)

    Underwood, Charlie J; Johanson, Zerina; Welten, Monique; Metscher, Brian; Rasch, Liam J; Fraser, Gareth J; Smith, Moya Meredith

    2015-01-01

    Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the

  14. Phylogenomic analyses reveal convergent patterns of adaptive evolution in elephant and human ancestries.

    Science.gov (United States)

    Goodman, Morris; Sterner, Kirstin N; Islam, Munirul; Uddin, Monica; Sherwood, Chet C; Hof, Patrick R; Hou, Zhuo-Cheng; Lipovich, Leonard; Jia, Hui; Grossman, Lawrence I; Wildman, Derek E

    2009-12-01

    Specific sets of brain-expressed genes, such as aerobic energy metabolism genes, evolved adaptively in the ancestry of humans and may have evolved adaptively in the ancestry of other large-brained mammals. The recent addition of genomes from two afrotherians (elephant and tenrec) to the expanding set of publically available sequenced mammalian genomes provided an opportunity to test this hypothesis. Elephants resemble humans by having large brains and long life spans; tenrecs, in contrast, have small brains and short life spans. Thus, we investigated whether the phylogenomic patterns of adaptive evolution are more similar between elephant and human than between either elephant and tenrec lineages or human and mouse lineages, and whether aerobic energy metabolism genes are especially well represented in the elephant and human patterns. Our analyses encompassed approximately 6,000 genes in each of these lineages with each gene yielding extensive coding sequence matches in interordinal comparisons. Each gene's nonsynonymous and synonymous nucleotide substitution rates and dN/dS ratios were determined. Then, from gene ontology information on genes with the higher dN/dS ratios, we identified the more prevalent sets of genes that belong to specific functional categories and that evolved adaptively. Elephant and human lineages showed much slower nucleotide substitution rates than tenrec and mouse lineages but more adaptively evolved genes. In correlation with absolute brain size and brain oxygen consumption being largest in elephants and next largest in humans, adaptively evolved aerobic energy metabolism genes were most evident in the elephant lineage and next most evident in the human lineage.

  15. Banding patterns and chromosomal evolution in five species of neotropical Teiinae lizards (Squamata: Teiidae).

    Science.gov (United States)

    dos Santos, Rodrigo Marques Lima; Pellegrino, Katia Cristina Machado; Rodrigues, Miguel Trefaut; Yonenaga-Yassuda, Yatiyo

    2007-11-01

    Karyotypes of five species of South American teiid lizards from subfamily Teiinae: Ameiva ameiva, Kentropyx calcarata, K. paulensis, K. vanzoi (2n = 50, all acrocentric), and Cnemidophorus ocellifer (2n = 50, all biarmed), are herein described and compared on the basis of conventional and silver staining, and CBG and RBG banding patterns. Meiotic data are also included. Karyotypes of K. paulensis, K. vanzoi, and C. ocellifer are reported here for the first time. Inter-generic variability in Ag-NORs location was detected with NORs occurring at the end of long arm of pair 1 in K. calcarata, K. paulensis, and K. vanzoi; pair 5 in C. ocellifer and pair 7 in A. ameiva. The location of NORs, along with the karyological differences between A. ameiva and the Central American species (A. auberi), corroboretes the molecular-based hypothesis that the genus Ameiva is paraphyletic. Inter-populational heteromorphism in Ag-NORs size was detected between populations of C. ocellifer. RBG and CBG banding data demonstrated that the biarmed condition of the C. ocellifer chromosomes is due to multiple pericentric inversion events instead of addition of constitutive heterochromatin. Differential-staining techniques used here revealed valuable information about Teiinae karyotypic diversity and made it possible to compare these species, contributing to both the better comprehension of their chromosomal evolution and issues on taxa systematics. PMID:17206461

  16. Computational Experiment Approach to Controlled Evolution of Procurement Pattern in Cluster Supply Chain

    Directory of Open Access Journals (Sweden)

    Xiao Xue

    2015-01-01

    Full Text Available Companies have been aware of the benefits of developing Cluster Supply Chains (CSCs, and they are spending a great deal of time and money attempting to develop the new business pattern. Yet, the traditional techniques for identifying CSCs have strong theoretical antecedents, but seem to have little traction in the field. We believe this is because the standard techniques fail to capture evolution over time, nor provide useful intervention measures to reach goals. To address these problems, we introduce an agent-based modeling approach to evaluate CSCs. Taking collaborative procurement as research object, our approach is composed of three parts: model construction, model instantiation, and computational experiment. We use the approach to explore the service charging policy problem in collaborative procurement. Three kinds of service charging polices are compared in the same experiment environment. Finally, “Fixed Cost” is identified as the optimal policy under the stable market environment. The case study can help us to understand the workflow of applying the approach, and provide valuable decision support applications to industry.

  17. Patterns of microsatellite evolution inferred from the Helianthus annuus (Asteraceae) transcriptome

    Indian Academy of Sciences (India)

    Sreepriya Pramod; Andy D. Perkins; Mark E. Welch

    2014-08-01

    The distribution of microsatellites in exons, and their association with gene ontology (GO) terms is explored to elucidate patterns of microsatellite evolution in the common sunflower, Helianthus annuus. The relative position, motif, size and level of impurity were estimated for each microsatellite in the unigene database available from the Compositae Genome Project (CGP), and statistical analyses were performed to determine if differences in microsatellite distributions and enrichment within certain GO terms were significant. There are more translated than untranslated microsatellites, implying that many bring about structural changes in proteins. However, the greatest density is observed within the UTRs, particularly 5′UTRs. Further, UTR microsatellites are purer and longer than coding region microsatellites. This suggests that UTR microsatellites are either younger and under more relaxed constraints, or that purifying selection limits impurities, and directional selection favours their expansion. GOs associated with response to various environmental stimuli including water deprivation and salt stress were significantly enriched with microsatellites. This may suggest that these GOs are more labile in plant genomes, or that selection has favoured the maintenance of microsatellites in these genes over others. This study shows that the distribution of transcribed microsatellites in H. annuus is nonrandom, the coding region microsatellites are under greater constraint compared to the UTR microsatellites, and that these sequences are enriched within genes that regulate plant responses to environmental stress and stimuli.

  18. Interactive Exploratory Visualization of 2D Vector Fields

    NARCIS (Netherlands)

    Isenberg, Tobias; Everts, Maarten H.; Grubert, Jens; Carpendale, Sheelagh

    2008-01-01

    In this paper we present several techniques to interactively explore representations of 2D vector fields. Through a set of simple hand postures used on large, touch-sensitive displays, our approach allows individuals to custom-design glyphs (arrows, lines, etc.) that best reveal patterns of the unde

  19. ChIP-Seq-Annotated Heliconius erato Genome Highlights Patterns of cis-Regulatory Evolution in Lepidoptera.

    Science.gov (United States)

    Lewis, James J; van der Burg, Karin R L; Mazo-Vargas, Anyi; Reed, Robert D

    2016-09-13

    Uncovering phylogenetic patterns of cis-regulatory evolution remains a fundamental goal for evolutionary and developmental biology. Here, we characterize the evolution of regulatory loci in butterflies and moths using chromatin immunoprecipitation sequencing (ChIP-seq) annotation of regulatory elements across three stages of head development. In the process we provide a high-quality, functionally annotated genome assembly for the butterfly, Heliconius erato. Comparing cis-regulatory element conservation across six lepidopteran genomes, we find that regulatory sequences evolve at a pace similar to that of protein-coding regions. We also observe that elements active at multiple developmental stages are markedly more conserved than elements with stage-specific activity. Surprisingly, we also find that stage-specific proximal and distal regulatory elements evolve at nearly identical rates. Our study provides a benchmark for genome-wide patterns of regulatory element evolution in insects, and it shows that developmental timing of activity strongly predicts patterns of regulatory sequence evolution. PMID:27626657

  20. ChIP-Seq-Annotated Heliconius erato Genome Highlights Patterns of cis-Regulatory Evolution in Lepidoptera

    Directory of Open Access Journals (Sweden)

    James J. Lewis

    2016-09-01

    Full Text Available Uncovering phylogenetic patterns of cis-regulatory evolution remains a fundamental goal for evolutionary and developmental biology. Here, we characterize the evolution of regulatory loci in butterflies and moths using chromatin immunoprecipitation sequencing (ChIP-seq annotation of regulatory elements across three stages of head development. In the process we provide a high-quality, functionally annotated genome assembly for the butterfly, Heliconius erato. Comparing cis-regulatory element conservation across six lepidopteran genomes, we find that regulatory sequences evolve at a pace similar to that of protein-coding regions. We also observe that elements active at multiple developmental stages are markedly more conserved than elements with stage-specific activity. Surprisingly, we also find that stage-specific proximal and distal regulatory elements evolve at nearly identical rates. Our study provides a benchmark for genome-wide patterns of regulatory element evolution in insects, and it shows that developmental timing of activity strongly predicts patterns of regulatory sequence evolution.

  1. 2D growth processes: SLE and Loewner chains

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Michel [Service de Physique Theorique de Saclay, CE-Saclay, 91191 Gif-sur-Yvette (France) and Laboratoire de Physique Theorique, Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris (France)]. E-mail: michel.bauer@cea.fr; Bernard, Denis [Service de Physique Theorique de Saclay, CE-Saclay, 91191 Gif-sur-Yvette (France) and Laboratoire de Physique Theorique, Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris (France)]. E-mail: denis.bernard@cea.fr

    2006-10-15

    This review provides an introduction to two dimensional growth processes. Although it covers a variety of processes such as diffusion limited aggregation, it is mostly devoted to a detailed presentation of stochastic Schramm-Loewner evolutions (SLE) which are Markov processes describing interfaces in 2D critical systems. It starts with an informal discussion, using numerical simulations, of various examples of 2D growth processes and their connections with statistical mechanics. SLE is then introduced and Schramm's argument mapping conformally invariant interfaces to SLE is explained. A substantial part of the review is devoted to reveal the deep connections between statistical mechanics and processes, and more specifically to the present context, between 2D critical systems and SLE. Some of the remarkable properties of SLE are explained, together with the tools for computing with it. This review has been written with the aim of filling the gap between the mathematical and the physical literature on the subject.

  2. The evolution of pattern camouflage strategies in waterfowl and game birds

    OpenAIRE

    Marshall, Kate L A; Gluckman, Thanh-Lan

    2015-01-01

    Visual patterns are common in animals. A broad survey of the literature has revealed that different patterns have distinct functions. Irregular patterns (e.g., stipples) typically function in static camouflage, whereas regular patterns (e.g., stripes) have a dual function in both motion camouflage and communication. Moreover, irregular and regular patterns located on different body regions (?bimodal? patterning) can provide an effective compromise between camouflage and communication and/or e...

  3. Handling and Use of Oxygen by Pancrustaceans: Conserved Patterns and the Evolution of Respiratory Structures.

    Science.gov (United States)

    Harrison, Jon F

    2015-11-01

    The handling and use of oxygen are central to physiological function of all pancrustaceans. Throughout the Pancrustacea, ventilation is controlled by a central oxygen-sensitive pattern generator. The ancestral condition was likely to achieve ventilation of the gills via leg-associated or mouth-associated muscles, but in insects and some air-breathing crustaceans, new muscles were recruited for this purpose, including intersegmental muscles likely used previously for posture and locomotion. Many aspects of the sensing of oxygen and the occurrence of responses to hypoxia (increased ventilation, depressed growth and metabolic rate, developmental changes that enhance the delivery of oxygen) appear common across most pancrustaceans, but there is tremendous variation across species. Some of this can be explained by habitat (e.g., ventilation of the internal medium occurs in terrestrial species and of the external medium in aquatic species; rearing under hypoxia induces tracheal proliferation in terrestrial insects and hemocyanin production in aquatic crustaceans); some plausibly by evolutionary origin of some responses to hypoxia within the Pancrustacea (the most basal arthropods may lack a ventilatory response to hypoxia); and some by the availability of environmental oxygen (animals adapted to survive hypoxia turn on the response to hypoxia at a lower PO2). On average, crustaceans and insects have similar tolerances to prolonged anoxia, but species or life stages from habitats with a danger of being trapped in hypoxia can tolerate longer durations of anoxia. Lactate is the primary anaerobic end-product in crustaceans but some insects have evolved a more diverse array of anaerobic end-products, including ethanol, alanine, succinate, and acetate. Most clades of Pancrustacea are small and lack obvious respiratory structures. Gilled stem-pancrustaceans likely evolved in the Cambrian, and gills persist in large Ostracoda, Malacostraca, and Branchiopoda. Based on currently

  4. Evidence of host-virus co-evolution in tetranucleotide usage patterns of bacteriophages and eukaryotic viruses

    Directory of Open Access Journals (Sweden)

    Ghose Chandrabali

    2006-01-01

    Full Text Available Abstract Background Virus taxonomy is based on morphologic characteristics, as there are no widely used non-phenotypic measures for comparison among virus families. We examined whether there is phylogenetic signal in virus nucleotide usage patterns that can be used to determine ancestral relationships. The well-studied model of tail morphology in bacteriophage classification was used for comparison with nucleotide usage patterns. Tetranucleotide usage deviation (TUD patterns were chosen since they have previously been shown to contain phylogenetic signal similar to that of 16S rRNA. Results We found that bacteriophages have unique TUD patterns, representing genomic signatures that are relatively conserved among those with similar host range. Analysis of TUD-based phylogeny indicates that host influences are important in bacteriophage evolution, and phylogenies containing both phages and their hosts support their co-evolution. TUD-based phylogeny of eukaryotic viruses indicates that they cluster largely based on nucleic acid type and genome size. Similarities between eukaryotic virus phylogenies based on TUD and gene content substantiate the TUD methodology. Conclusion Differences between phenotypic and TUD analysis may provide clues to virus ancestry not previously inferred. As such, TUD analysis provides a complementary approach to morphology-based systems in analysis of virus evolution.

  5. SWS2 visual pigment evolution as a test of historically contingent patterns of plumage color evolution in Warblers

    OpenAIRE

    Bloch, Natasha I.; Morrow, James M; Chang, Belinda S. W.; Price, Trevor D

    2015-01-01

    Distantly related clades that occupy similar environments may differ due to the lasting imprint of their ancestors – historical contingency. The New World warblers (Parulidae) and Old World warblers (Phylloscopidae) are ecologically similar clades that differ strikingly in plumage coloration. We studied genetic and functional evolution of the short-wavelength sensitive visual pigments (SWS2 and SWS1) to ask if altered color perception could contribute to the plumage color differences between ...

  6. Patterns and Implications of Gene Gain and Loss in the Evolution of Prochlorococcus

    Energy Technology Data Exchange (ETDEWEB)

    Lapidus, Alla; Kettler, Gregory C.; Martiny, Adam C.; Huang, Katherine; Zucker, Jeremy; Coleman, Maureen L.; Rodrigue, Sebastien; Chen, Feng; Lapidus, Alla; Ferriera, Steven; Johnson, Justin; Steglich, Claudia; Church, George M.; Richardson, Paul; Chisholm, Sallie W.

    2007-07-30

    Prochlorococcus is a marine cyanobacterium that numerically dominates the mid-latitude oceans and is the smallest known oxygenic phototroph. Numerous isolatesfrom diverse areas of the world's oceans have been studied and shown to be physiologically and genetically distinct. All isolates described thus far can be assigned to either a tightly clustered high-light (HL)-adapted clade, or a more divergent low-light (LL)-adapted group. The 16S rRNA sequences of the entire Prochlorococcus group differ by at most 3percent, and the four initially published genomes revealed patterns of genetic differentiation that help explain physiological differences among the isolates. Here we describe the genomes of eight newly sequenced isolates and combine them with the first four genomes for a comprehensive analysis of the core (shared by all isolates) and flexible genes of the Prochlorococcus group, and the patterns of loss and gain of the flexible genes over the course of evolution. There are 1,273 genes that represent the core shared by all 12 genomes. They are apparently sufficient, according to metabolic reconstruction, to encode a functional cell. We describe a phylogeny for all 12 isolates by subjecting their complete proteomes to three different phylogenetic analyses. For each non-core gene, we used a maximum parsimony method to estimate which ancestor likely first acquired or lost each gene. Many of the genetic differences among isolates, especially for genes involved in outer membrane synthesis and nutrient transport, are found within the same clade. Nevertheless, we identified some genes defining HL and LL ecotypes, and clades within these broad ecotypes, helping to demonstrate the basis of HL and LL adaptations in Prochlorococcus. Furthermore, our estimates of gene gain events allow us to identify highly variable genomic islands that are not apparent through simple pairwise comparisons. These results emphasize the functional roles, especially those connected to outer

  7. Patterns and implications of gene gain and loss in the evolution of Prochlorococcus.

    Directory of Open Access Journals (Sweden)

    Gregory C Kettler

    2007-12-01

    Full Text Available Prochlorococcus is a marine cyanobacterium that numerically dominates the mid-latitude oceans and is the smallest known oxygenic phototroph. Numerous isolates from diverse areas of the world's oceans have been studied and shown to be physiologically and genetically distinct. All isolates described thus far can be assigned to either a tightly clustered high-light (HL-adapted clade, or a more divergent low-light (LL-adapted group. The 16S rRNA sequences of the entire Prochlorococcus group differ by at most 3%, and the four initially published genomes revealed patterns of genetic differentiation that help explain physiological differences among the isolates. Here we describe the genomes of eight newly sequenced isolates and combine them with the first four genomes for a comprehensive analysis of the core (shared by all isolates and flexible genes of the Prochlorococcus group, and the patterns of loss and gain of the flexible genes over the course of evolution. There are 1,273 genes that represent the core shared by all 12 genomes. They are apparently sufficient, according to metabolic reconstruction, to encode a functional cell. We describe a phylogeny for all 12 isolates by subjecting their complete proteomes to three different phylogenetic analyses. For each non-core gene, we used a maximum parsimony method to estimate which ancestor likely first acquired or lost each gene. Many of the genetic differences among isolates, especially for genes involved in outer membrane synthesis and nutrient transport, are found within the same clade. Nevertheless, we identified some genes defining HL and LL ecotypes, and clades within these broad ecotypes, helping to demonstrate the basis of HL and LL adaptations in Prochlorococcus. Furthermore, our estimates of gene gain events allow us to identify highly variable genomic islands that are not apparent through simple pairwise comparisons. These results emphasize the functional roles, especially those connected to

  8. KOREAN MOBILE OPERATORS' VALUE MAP FOR LTE D2D

    Directory of Open Access Journals (Sweden)

    Taisiya Kim

    2015-04-01

    Full Text Available Managing the wireless data traffic is a main concern for mobile network operators in Information of Things (IoT environment. Long Term Evolution Device to Device (LTE D2D is regarding as a solution for the spectrum problem. It will bring an impact on providers and the whole mobile environment. The main purpose of this study is to analyze the role of key players, who share spectrum with mobile operators, and to present the value map of relationship among Korean mobile operators and other key players in LTE D2D discovery (commercial channel, as complicated relationships of key players are expected. Then, this study suggests scenario for ‘Targeted Advertising’ service of LTE D2D. LTE D2D is early discussion stage and scenario has limitation of specific business model. However, results of this study are significant for the present stage and provide implications for future researches on strategies for LTE D2D environment.

  9. A pattern language for evolution in component-based software architectures

    OpenAIRE

    Ahmad, Aakash; Jamshidi, Pooyan; Pahl, Claus; Khaliq, Fawad

    2013-01-01

    peer-reviewed Modern software systems are prone to a continuous evolution under frequently varying requirements. Architecture-centric software evolution enables change in system structure and behavior while maintaining a global view of software to address evolution-centric tradeoffs. The Lehman???s law of continuing change demands for long-living and continuously evolving architectures to prolong the productive life and economic value of deployed software. However, the existing solutions f...

  10. PatEvol – A pattern language for evolution in component-based software architectures

    OpenAIRE

    Aakash, Ahmad; Jamshidi, Pooyan; Pahl, Claus; Khaliq, Fawad

    2013-01-01

    Modern software systems are prone to a continuous evolution under frequently varying requirements. Architecture-centric software evolution (ACSE) enables change in system structure and behavior while maintaining a global view of software to address evolution-centric tradeoffs. Lehman’s law of continuing change demands for long-living and continuously evolving architectures to prolong the productive life and economic value of software systems. To support a continuous change, the existing solut...

  11. A pattern language for evolution reuse in component-based software architectures

    OpenAIRE

    Abbasi, Aakash Ahmad

    2015-01-01

    Context: Modern software systems are prone to a continuous evolution under frequently varying requirements and changes in operational environments. Architecture-Centric Software Evolution (ACSE) enables changes in a system’s structure and behaviour while maintaining a global view of the software to address evolution-centric trade-offs. Lehman’s law of continuing change demands for long-living and continuously evolving architectures to prolong the productive life and economic value of software...

  12. Perspectives for spintronics in 2D materials

    Directory of Open Access Journals (Sweden)

    Wei Han

    2016-03-01

    Full Text Available The past decade has been especially creative for spintronics since the (rediscovery of various two dimensional (2D materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.

  13. Surface modelling for 2D imagery

    OpenAIRE

    Lieng, Henrik

    2014-01-01

    Vector graphics provides powerful tools for drawing scalable 2D imagery. With the rise of mobile computers, of different types of displays and image resolutions, vector graphics is receiving an increasing amount of attention. However, vector graphics is not the leading framework for creating and manipulating 2D imagery. The reason for this reluctance of employing vector graphical frameworks is that it is difficult to handle complex behaviour of colour across the 2D domain. ...

  14. Perspectives for Spintronics in 2D Materials

    OpenAIRE

    Wei Han

    2016-01-01

    The past decade has been especially creative for spintronics since the (re)discovery of various two dimensional (2D) materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.

  15. UNITS IN $F_2D_{2p}$

    OpenAIRE

    Kaur, Kuldeep; Khan, Manju

    2012-01-01

    Let $p$ be an odd prime, $D_{2p}$ be the dihedral group of order 2p, and $F_{2}$ be the finite field with two elements. If * denotes the canonical involution of the group algebra $F_2D_{2p}$, then bicyclic units are unitary units. In this note, we investigate the structure of the group $\\mathcal{B}(F_2D_{2p})$, generated by the bicyclic units of the group algebra $F_2D_{2p}$. Further, we obtain the structure of the unit group $\\mathcal{U}(F_2D_{2p})$ and the unitary subgroup $\\mathcal{U}_*(F_...

  16. 2D Barcode for DNA Encoding

    CERN Document Server

    Purcaru, Elena

    2012-01-01

    The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution - DNA2DBC - DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features of 2D barcode implementation for DNA.

  17. 2D Barcode for DNA Encoding

    Directory of Open Access Journals (Sweden)

    Elena Purcaru

    2011-09-01

    Full Text Available The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution – DNA2DBC – DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features of 2D barcode implementation for DNA.

  18. Three-dimensional shear-strain patterns induced by high-pressure torsion and their impact on hardness evolution

    International Nuclear Information System (INIS)

    Highlights: → Three-dimensional shear strain patterns were evaluated during high-pressure torsion. → Double-swirl patterns are visible on the top surfaces of discs in early stages of HPT. → Double-swirls ultimately evolve into a single swirl with increasing revolutions. → Microstructural evolution in HPT may deviate initially from rigid-body situation - Abstract: The shear strain imposed on austenite/ferrite duplex stainless steel discs at different stages of high-pressure torsion (HPT) processing was imaged in plan-view and cross-section using optical microscopy and scanning electron microscopy. The effect of the shear strain was correlated to the hardness evolution of the discs. The shear-strain patterns are complex and are different on the top and bottom surfaces of the discs. A double-swirl pattern emerged on the top surface in the early stages of HPT. These two centres of the swirl moved towards the centre of the disc as the numbers of HPT revolutions was increased and ultimately the double-swirl evolved into a single-swirl. Less regular shear-strain patterns were observed on the bottom surfaces of the discs. Multiple ring-like patterns with mirror symmetry over the central axes of the discs were visible from cross-sectional observations. Nanoindentation testing on the two surfaces and a cross-section of HPT discs showed that the hardness is insensitive to specific shear-strain patterns, but is closely related to the widths of the austenite and ferrite phase domains. Late in the deformation process, the hardness in the interior of an HPT disc may be higher than at either of the disc surfaces because of the development of finer microstructural phase distributions.

  19. Three-dimensional shear-strain patterns induced by high-pressure torsion and their impact on hardness evolution

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Y.; Wang, Y.B. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Figueiredo, R.B. [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais, Belo Horizonte, MG 31270-901 (Brazil); Chang, L. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Liao, X.Z., E-mail: xiaozhou.liao@sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006 (Australia); Kawasaki, M. [Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Zheng, W.L. [Shanghai Research Institute of Materials, 99 Handan Road, Shanghai 200437 (China); Ringer, S.P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006 (Australia); Langdon, T.G. [Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Materials Research Group, School of Engineering Sciences, University of Southampton, Southampton SO17 1BJ (United Kingdom); Zhu, Y.T. [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2011-06-15

    Highlights: > Three-dimensional shear strain patterns were evaluated during high-pressure torsion. > Double-swirl patterns are visible on the top surfaces of discs in early stages of HPT. > Double-swirls ultimately evolve into a single swirl with increasing revolutions. > Microstructural evolution in HPT may deviate initially from rigid-body situation - Abstract: The shear strain imposed on austenite/ferrite duplex stainless steel discs at different stages of high-pressure torsion (HPT) processing was imaged in plan-view and cross-section using optical microscopy and scanning electron microscopy. The effect of the shear strain was correlated to the hardness evolution of the discs. The shear-strain patterns are complex and are different on the top and bottom surfaces of the discs. A double-swirl pattern emerged on the top surface in the early stages of HPT. These two centres of the swirl moved towards the centre of the disc as the numbers of HPT revolutions was increased and ultimately the double-swirl evolved into a single-swirl. Less regular shear-strain patterns were observed on the bottom surfaces of the discs. Multiple ring-like patterns with mirror symmetry over the central axes of the discs were visible from cross-sectional observations. Nanoindentation testing on the two surfaces and a cross-section of HPT discs showed that the hardness is insensitive to specific shear-strain patterns, but is closely related to the widths of the austenite and ferrite phase domains. Late in the deformation process, the hardness in the interior of an HPT disc may be higher than at either of the disc surfaces because of the development of finer microstructural phase distributions.

  20. Annotated Bibliography of EDGE2D Use

    International Nuclear Information System (INIS)

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables

  1. Port Adriano, 2D-Model Tests

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Jensen, Palle Meinert

    This report present the results of 2D physical model tests (length scale 1:50) carried out in a waveflume at Dept. of Civil Engineering, Aalborg University (AAU).......This report present the results of 2D physical model tests (length scale 1:50) carried out in a waveflume at Dept. of Civil Engineering, Aalborg University (AAU)....

  2. Annotated Bibliography of EDGE2D Use

    Energy Technology Data Exchange (ETDEWEB)

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  3. Patterns of Genome Evolution among the Microsporidian Parasites Encephalitozoon cuniculi, Antonospora locustae and Enterocytozoon bieneusi

    OpenAIRE

    Corradi, Nicolas; Akiyoshi, Donna E.; Morrison, Hilary G; Feng, Xiaochuan; Weiss, Louis M.; Tzipori, Saul; Patrick J Keeling

    2007-01-01

    Background Microsporidia are intracellular parasites that are highly-derived relatives of fungi. They have compacted genomes and, despite a high rate of sequence evolution, distantly related species can share high levels of gene order conservation. To date, only two species have been analysed in detail, and data from one of these largely consists of short genomic fragments. It is therefore difficult to determine how conservation has been maintained through microsporidian evolution, and imposs...

  4. Explaining the Evolution of Domestic Nanotechnology Companies - Survival Patterns of a Young and Emerging Technology

    OpenAIRE

    Funken, Melanie

    2012-01-01

    Nanotechnology (NT) is often considered to be the essential technology of the future. Since the economy shapes the competiveness of a country to a great extent, factors fostering or hindering the evolution of NT companies need to be disentangled. This thesis associates the evolution of domestic NT companies to several kinds of knowledge. It provides an empirical investigation using an industry-dynamic and a network-theoretic approach.

  5. Diversification of the expression patterns and developmental functions of the Dishevelled gene family during chordate evolution

    OpenAIRE

    Gray, Ryan S.; Bayly, Robbie D.; Green, Stephen A.; Agarwala, Seema; Lowe, Christopher J.; Wallingford, John B.

    2009-01-01

    Dishevelled (Dvl) proteins are key transducers of Wnt signaling encoded by members of a multi-gene family in vertebrates. We report here the divergent, tissue-specific expression patterns for all three Dvl genes in Xenopus embryos, which contrast dramatically with their expression patterns in mice. Moreover, we find that the expression patterns of Dvl genes in the chick diverge significantly from those of Xenopus. In addition, in hemichordates, an outgroup to chordates, we find that the one D...

  6. A mechanistic description of the formation and evolution of vegetation patterns

    OpenAIRE

    R. Foti; Ramírez, J. A.

    2013-01-01

    Vegetation patterns are a common and well-defined characteristic of many landscapes. In this paper we explore some of the physical mechanisms responsible for the establishment of self-organized, non-random vegetation patterns that arise at the hillslope scale in many areas of the world, especially in arid and semi-arid regions. In doing so, we provide a fundamental mechanistic understanding of the dynamics of vegetation pattern formation and development. Reciprocal effects of vegetation on th...

  7. A mechanistic description of the formation and evolution of vegetation patterns

    Directory of Open Access Journals (Sweden)

    R. Foti

    2012-07-01

    Full Text Available Vegetation patterns are a common and well-defined characteristic of many landscapes. In this paper we explore some of the physical mechanisms responsible for the establishment of self-organized, non-random vegetation patterns that arise at the hillslope scale in many areas of the world, especially in arid and semi-arid regions. In doing so, we provide a fundamental mechanistic understanding of the dynamics of vegetation pattern formation and development. Reciprocal effects of vegetation on the hillslope thermodynamics, runoff production and run-on infiltration, root density, surface albedo and soil moisture content are analyzed. In particular, we: (1 present a physically based mechanistic description of processes leading to vegetation pattern formation; (2 quantify the relative impact of each process on pattern formation; and (3 describe the relationships between vegetation patterns and the climatic, hydraulic and topographic characteristics of the system. We validate the model by comparing simulations with observed natural patterns in the areas of Niger near Niamey and Somalia near Garoowe. Our analyses suggest that the phenomenon of pattern formation is primarily driven by run-on infiltration and mechanisms of facilitation/inhibition among adjacent vegetation groups mediated by vegetation effects on soil properties and controls on soil moisture and albedo. Nonetheless, even in presence of those mechanisms, patterns arise only when the climatic conditions, particularly annual precipitation and net radiation, are favorable.

  8. A mechanistic description of the formation and evolution of vegetation patterns

    Directory of Open Access Journals (Sweden)

    R. Foti

    2013-01-01

    Full Text Available Vegetation patterns are a common and well-defined characteristic of many landscapes. In this paper we explore some of the physical mechanisms responsible for the establishment of self-organized, non-random vegetation patterns that arise at the hillslope scale in many areas of the world, especially in arid and semi-arid regions. In doing so, we provide a fundamental mechanistic understanding of the dynamics of vegetation pattern formation and development. Reciprocal effects of vegetation on the hillslope thermodynamics, runoff production and run-on infiltration, root density, surface albedo and soil moisture content are analyzed. In particular, we: (1 present a physically based mechanistic description of processes leading to vegetation pattern formation; (2 quantify the relative impact of each process on pattern formation; and (3 describe the relationships between vegetation patterns and the climatic, hydraulic and topographic characteristics of the system. We validate the model by comparing simulations with observed natural patterns in the areas of Niger near Niamey and Somalia near Garoowe. Our analyses suggest that the phenomenon of pattern formation is primarily driven by run-on infiltration and mechanisms of facilitation/inhibition among adjacent vegetation groups, mediated by vegetation effects on soil properties and controls on soil moisture and albedo. Nonetheless, even in presence of those mechanisms, patterns arise only when the climatic conditions, particularly annual precipitation and net radiation, are favorable.

  9. Correlated evolution of life-history with size at maturity in Daphnia pulicaria: patterns within and between populations.

    Science.gov (United States)

    Baer, Charles F; Lynch, Michael

    2003-04-01

    Explaining the repeated evolution of similar sets of traits under similar environmental conditions is an important issue in evolutionary biology. The extreme alternative classes of explanations for correlated suites of traits are optimal adaptation and genetic constraint resulting from pleiotropy. Adaptive explanations presume that individual traits are free to evolve to their local optima and that convergent evolution represents particularly adaptive combinations of traits. Alternatively, if pleiotropy is strong and difficult to break, strong selection on one or a few particularly important characters would be expected to result in consistent correlated evolution of associated traits. If pleiotropy is common, we predict that the pattern of divergence among populations will consistently reflect the within-population genetic architecture. To test the idea that the multivariate life-history phenotype is largely a byproduct of strong selection on body size, we imposed divergent artificial selection on size at maturity upon two populations of the cladoceran Daphnia pulicaria, chosen on the basis of their extreme divergence in body size. Overall, the trajectory of divergence between the two natural populations did not differ from that predicted by the genetic architecture within each population. However, the pattern of correlated responses suggested the presence of strong pleiotropic constraints only for adult body size and not for other life-history traits. One trait, offspring size, appears to have evolved in a way different from that expected from the within-population genetic architecture and may be under stabilizing selection.

  10. 2D materials for nanophotonic devices

    Science.gov (United States)

    Xu, Renjing; Yang, Jiong; Zhang, Shuang; Pei, Jiajie; Lu, Yuerui

    2015-12-01

    Two-dimensional (2D) materials have become very important building blocks for electronic, photonic, and phononic devices. The 2D material family has four key members, including the metallic graphene, transition metal dichalcogenide (TMD) layered semiconductors, semiconducting black phosphorous, and the insulating h-BN. Owing to the strong quantum confinements and defect-free surfaces, these atomically thin layers have offered us perfect platforms to investigate the interactions among photons, electrons and phonons. The unique interactions in these 2D materials are very important for both scientific research and application engineering. In this talk, I would like to briefly summarize and highlight the key findings, opportunities and challenges in this field. Next, I will introduce/highlight our recent achievements. We demonstrated atomically thin micro-lens and gratings using 2D MoS2, which is the thinnest optical component around the world. These devices are based on our discovery that the elastic light-matter interactions in highindex 2D materials is very strong. Also, I would like to introduce a new two-dimensional material phosphorene. Phosphorene has strongly anisotropic optical response, which creates 1D excitons in a 2D system. The strong confinement in phosphorene also enables the ultra-high trion (charged exciton) binding energies, which have been successfully measured in our experiments. Finally, I will briefly talk about the potential applications of 2D materials in energy harvesting.

  11. Internal Photoemission Spectroscopy of 2-D Materials

    Science.gov (United States)

    Nguyen, Nhan; Li, Mingda; Vishwanath, Suresh; Yan, Rusen; Xiao, Shudong; Xing, Huili; Cheng, Guangjun; Hight Walker, Angela; Zhang, Qin

    Recent research has shown the great benefits of using 2-D materials in the tunnel field-effect transistor (TFET), which is considered a promising candidate for the beyond-CMOS technology. The on-state current of TFET can be enhanced by engineering the band alignment of different 2D-2D or 2D-3D heterostructures. Here we present the internal photoemission spectroscopy (IPE) approach to determine the band alignments of various 2-D materials, in particular SnSe2 and WSe2, which have been proposed for new TFET designs. The metal-oxide-2-D semiconductor test structures are fabricated and characterized by IPE, where the band offsets from the 2-D semiconductor to the oxide conduction band minimum are determined by the threshold of the cube root of IPE yields as a function of photon energy. In particular, we find that SnSe2 has a larger electron affinity than most semiconductors and can be combined with other semiconductors to form near broken-gap heterojunctions with low barrier heights which can produce a higher on-state current. The details of data analysis of IPE and the results from Raman spectroscopy and spectroscopic ellipsometry measurements will also be presented and discussed.

  12. 2D supergravity in p+1 dimensions

    OpenAIRE

    Gustafsson, H.; Lindstrom, U.

    1998-01-01

    We describe new $N$-extended 2D supergravities on a $(p+1)$-dimensional (bosonic) space. The fundamental objects are moving frame densities that equip each $(p+1)$-dimensional point with a 2D ``tangent space''. The theory is presented in a $[p+1, 2]$ superspace. For the special case of $p=1$ we recover the 2D supergravities in an unusual form. The formalism has been developed with applications to the string-parton picture of $D$-branes at strong coupling in mind.

  13. 2D Barcode for DNA Encoding

    OpenAIRE

    Elena Purcaru; Cristian Toma

    2012-01-01

    The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution – DNA2DBC – DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features ...

  14. Unbounded growth patterns of reproducing, competing polymers—similarities to biological evolution

    Science.gov (United States)

    Gregor Worst, Emanuel; Zimmer, Philipp; Wollrab, Eva; Kruse, Karsten; Ott, Albrecht

    2016-10-01

    Since the origin of life the interplay between reproduction, variation, and selection has been driving the emergence of new species. The evolution of the Earth’s biosphere appears to innovate unceasingly instead of coming to a stall. Here, we introduce a model system of linear molecules where new polymers appear by spontaneous ligation. The polymers proliferate following a template-based mechanism. Our combined experimental and theoretical study shows that for sufficiently rapid autocatalysis the reproduction process selects particular lengths—while ever longer polymers emerge. We suggest similarities to biological evolution.

  15. 2D Saturable Absorbers for Fibre Lasers

    Directory of Open Access Journals (Sweden)

    Robert I. Woodward

    2015-11-01

    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  16. Beltrami States in 2D Electron Magnetohydrodynamics

    OpenAIRE

    Shivamoggi, B. K.

    2015-01-01

    In this paper, the Hamiltonian formulations along with the Poisson brackets for two-dimensional (2D) electron magnetohydrodynamics (EMHD) flows are developed. These formulations are used to deduce the Beltrami states for 2D EMHD flows. In the massless electron limit, the EMHD Beltrami states reduce to the force-free states, though there is no force-free Beltrami state in the general EMHD case.

  17. Pigment pattern evolution by differential deployment of neural crest and post-embryonic melanophore lineages in Danio fishes.

    Science.gov (United States)

    Quigley, Ian K; Turner, Jessica M; Nuckels, Richard J; Manuel, Joan L; Budi, Erine H; MacDonald, Erin L; Parichy, David M

    2004-12-01

    Latent precursors or stem cells of neural crest origin are present in a variety of post-embryonic tissues. Although these cells are of biomedical interest for roles in human health and disease, their potential evolutionary significance has been underappreciated. As a first step towards elucidating the contributions of such cells to the evolution of vertebrate form, we investigated the relative roles of neural crest cells and post-embryonic latent precursors during the evolutionary diversification of adult pigment patterns in Danio fishes. These pigment patterns result from the numbers and arrangements of embryonic melanophores that are derived from embryonic neural crest cells, as well as from post-embryonic metamorphic melanophores that are derived from latent precursors of presumptive neural crest origin. In the zebrafish D. rerio, a pattern of melanophore stripes arises during the larval-to-adult transformation by the recruitment of metamorphic melanophores from latent precursors. Using a comparative approach in the context of new phylogenetic data, we show that adult pigment patterns in five additional species also arise from metamorphic melanophores, identifying this as an ancestral mode of adult pigment pattern development. By contrast, superficially similar adult stripes of D. nigrofasciatus (a sister species to D. rerio) arise by the reorganization of melanophores that differentiated at embryonic stages, with a diminished contribution from metamorphic melanophores. Genetic mosaic and molecular marker analyses reveal evolutionary changes that are extrinsic to D. nigrofasciatus melanophore lineages, including a dramatic reduction of metamorphic melanophore precursors. Finally, interspecific complementation tests identify a candidate genetic pathway for contributing to the evolutionary reduction in metamorphic melanophores and the increased contribution of early larval melanophores to D. nigrofasciatus adult pigment pattern development. These results

  18. Glitter in a 2D monolayer.

    Science.gov (United States)

    Yang, Li-Ming; Dornfeld, Matthew; Frauenheim, Thomas; Ganz, Eric

    2015-10-21

    We predict a highly stable and robust atomically thin gold monolayer with a hexagonal close packed lattice stabilized by metallic bonding with contributions from strong relativistic effects and aurophilic interactions. We have shown that the framework of the Au monolayer can survive 10 ps MD annealing simulations up to 1400 K. The framework is also able to survive large motions out of the plane. Due to the smaller number of bonds per atom in the 2D layer compared to the 3D bulk we observe significantly enhanced energy per bond (0.94 vs. 0.52 eV per bond). This is similar to the increase in bond strength going from 3D diamond to 2D graphene. It is a non-magnetic metal, and was found to be the global minima in the 2D space. Phonon dispersion calculations demonstrate high kinetic stability with no negative modes. This 2D gold monolayer corresponds to the top monolayer of the bulk Au(111) face-centered cubic lattice. The close-packed lattice maximizes the aurophilic interactions. We find that the electrons are completely delocalized in the plane and behave as 2D nearly free electron gas. We hope that the present work can inspire the experimental fabrication of novel free standing 2D metal systems.

  19. 2d index and surface operators

    Science.gov (United States)

    Gadde, Abhijit; Gukov, Sergei

    2014-03-01

    In this paper we compute the superconformal index of 2d (2, 2) supersymmetric gauge theories. The 2d superconformal index, a.k.a. flavored elliptic genus, is computed by a unitary matrix integral much like the matrix integral that computes the 4d superconformal index. We compute the 2d index explicitly for a number of examples. In the case of abelian gauge theories we see that the index is invariant under flop transition and under CY-LG correspondence. The index also provides a powerful check of the Seiberg-type duality for non-abelian gauge theories discovered by Hori and Tong. In the later half of the paper, we study half-BPS surface operators in = 2 super-conformal gauge theories. They are engineered by coupling the 2d (2, 2) supersymmetric gauge theory living on the support of the surface operator to the 4d = 2 theory, so that different realizations of the same surface operator with a given Levi type are related by a 2d analogue of the Seiberg duality. The index of this coupled system is computed by using the tools developed in the first half of the paper. The superconformal index in the presence of surface defect is expected to be invariant under generalized S-duality. We demonstrate that it is indeed the case. In doing so the Seiberg-type duality of the 2d theory plays an important role.

  20. The Pattern and Evolution of the Permian Palaeobiogeography and Tectonic Palaeogeography in Jilin and Heilongjiang Orogenic Belt

    Institute of Scientific and Technical Information of China (English)

    Peng Xiangdong; Li Xiaomin; Liu Pengju

    2000-01-01

    The orogenic belt locates between the North China plate and Siberia plate. The Permian palaeobiogeography and tectonic palaeogeography changed quickly and clearly. The line from Changchun to Yanji is an important palaeobiogeographic provincing line, which may be the collission suture belt of the North China plate and north middle massifs. The orogenic belt has been divided into 2 regions: the North middle massif region and the North Margin of North China plate, the pattern and evolution of Permian palaeobiogeography in the present area were discussed and the Permian biota mixture and its significants were analysed. Then, Based on the above, the Permian tectonic palaeogeography of the orogenic belt is reconstructed.

  1. Patterns of genome evolution among the microsporidian parasites Encephalitozoon cuniculi, Antonospora locustae and Enterocytozoon bieneusi.

    Directory of Open Access Journals (Sweden)

    Nicolas Corradi

    Full Text Available BACKGROUND: Microsporidia are intracellular parasites that are highly-derived relatives of fungi. They have compacted genomes and, despite a high rate of sequence evolution, distantly related species can share high levels of gene order conservation. To date, only two species have been analysed in detail, and data from one of these largely consists of short genomic fragments. It is therefore difficult to determine how conservation has been maintained through microsporidian evolution, and impossible to identify whether certain regions are more prone to genomic stasis. PRINCIPAL FINDINGS: Here, we analyse three large fragments of the Enterocytozoon bieneusi genome (in total 429 kbp, a species of medical significance. A total of 296 ORFs were identified, annotated and their context compared with Encephalitozoon cuniculi and Antonospora locustae. Overall, a high degree of conservation was found between all three species, and interestingly the level of conservation was similar in all three pairwise comparisons, despite the fact that A. locustae is more distantly related to E. cuniculi and E. bieneusi than either are to each other. CONCLUSIONS/SIGNIFICANCE: Any two genes that are found together in any pair of genomes are more likely to be conserved in the third genome as well, suggesting that a core of genes tends to be conserved across the entire group. The mechanisms of rearrangments identified among microsporidian genomes were consistent with a very slow evolution of their architecture, as opposed to the very rapid sequence evolution reported for these parasites.

  2. 2D molybdenum disulphide (2D-MoS2) modified electrodes explored towards the oxygen reduction reaction

    Science.gov (United States)

    Rowley-Neale, Samuel J.; Fearn, Jamie M.; Brownson, Dale A. C.; Smith, Graham C.; Ji, Xiaobo; Banks, Craig E.

    2016-08-01

    Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm-2 modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.Two-dimensional molybdenum disulphide nanosheets

  3. 2-D DOA Estimation Based on 2D-MUSIC%基于2D-MUSIC算法的DOA估计

    Institute of Scientific and Technical Information of China (English)

    康亚芳; 王静; 张清泉; 行小帅

    2014-01-01

    This paper discussed the performance of classical two-dimensional DOA estimation with 2D-MUSIC, based on the mathematical model of planar array and 2D-MUSIC DOA estimation, Taking uniform planar array for example, comput-er simulation experiment was carried for the effect of three kinds of different parameters on 2-D DOA estimation, and the simulation results were analyzed. And also verification test about the corresponding algorithm performance under the differ-ent parameters was discussed.%利用经典的2D-MUSIC算法对二维阵列的DOA估计进行了研究,在平面阵列数学模型以及2D-MUSIC算法的DOA估计模型基础上,以均匀平面阵列为例,对3种不同参数的DOA估计进行了计算机仿真,分析了仿真结果。得出了在不同参数变化趋势下DOA估计的相应变化情况。

  4. Shaped Beam Pattern Synthesis of Antenna Arrays Using Composite Differential Evolution with Eigenvector-Based Crossover Operator

    Directory of Open Access Journals (Sweden)

    Sotirios K. Goudos

    2015-01-01

    Full Text Available This paper addresses the problem of designing shaped beam patterns with arbitrary arrays subject to constraints. The constraints could include the sidelobe level suppression in specified angular intervals, the mainlobe halfpower beamwidth, and the predefined number of elements. In this paper, we propose a new Differential Evolution algorithm, which combines Composite DE with an eigenvector-based crossover operator (CODE-EIG. This operator utilizes eigenvectors of covariance matrix of individual solutions, which makes the crossover rotationally invariant. We apply this novel design method to shaped beam pattern synthesis for linear and conformal arrays. We compare this algorithm with other popular algorithms and DE variants. The results show CODE-EIG outperforms the other DE algorithms in terms of statistical results and convergence speed.

  5. Reduced sleep duration mediates decreases in striatal D2/D3 receptor availability in cocaine abusers.

    Science.gov (United States)

    Wiers, C E; Shumay, E; Cabrera, E; Shokri-Kojori, E; Gladwin, T E; Skarda, E; Cunningham, S I; Kim, S W; Wong, T C; Tomasi, D; Wang, G-J; Volkow, N D

    2016-01-01

    Neuroimaging studies have documented reduced striatal dopamine D2/D3 receptor (D2/D3R) availability in cocaine abusers, which has been associated with impaired prefrontal activity and vulnerability for relapse. However, the mechanism(s) underlying the decreases in D2/D3R remain poorly understood. Recent studies have shown that sleep deprivation is associated with a downregulation of striatal D2/D3R in healthy volunteers. As cocaine abusers have disrupted sleep patterns, here we investigated whether reduced sleep duration mediates the relationship between cocaine abuse and low striatal D2/D3R availability. We used positron emission tomography with [(11)C]raclopride to measure striatal D2/D3R availability in 24 active cocaine abusers and 21 matched healthy controls, and interviewed them about their daily sleep patterns. Compared with controls, cocaine abusers had shorter sleep duration, went to bed later and reported longer periods of sleep disturbances. In addition, cocaine abusers had reduced striatal D2/D3R availability. Sleep duration predicted striatal D2/D3R availability and statistically mediated the relationship between cocaine abuse and striatal D2/D3R availability. These findings suggest that impaired sleep patterns contribute to the low striatal D2/D3R availability in cocaine abusers. As sleep impairments are similarly observed in other types of substance abusers (for example, alcohol and methamphetamine), this mechanism may also underlie reductions in D2/D3R availability in these groups. The current findings have clinical implications suggesting that interventions to improve sleep patterns in cocaine abusers undergoing detoxification might be beneficial in improving their clinical outcomes. PMID:26954979

  6. Surface segregation of InGaAs films by the evolution of reflection high-energy electron diffraction patterns

    International Nuclear Information System (INIS)

    Surface segregation is studied via the evolution of reflection high-energy electron diffraction (RHEED) patterns under different values of As4 BEP for InGaAs films. When the As4 BEP is set to be zero, the RHEED pattern keeps a 4×3/(n × 3) structure with increasing temperature, and surface segregation takes place until 470 °C. The RHEED pattern develops into a metal-rich (4 × 2) structure as temperature increases to 495 °C. The reason for this is that surface segregation makes the In inside the InGaAs film climb to its surface. With the temperature increasing up to 515 °C, the RHEED pattern turns into a GaAs(2 × 4) structure due to In desorption. While the As4 BEP comes up to a specific value (1.33 × 10-4 Pa−1.33 × 10-3 Pa), the surface temperature can delay the segregation and desorption. We find that As4 BEP has a big influence on surface desorption, while surface segregation is more strongly dependent on temperature than surface desorption. (condensed matter: structural, mechanical, and thermal properties)

  7. Surface segregation of InGaAs films by the evolution of reflection high-energy electron diffraction patterns

    Institute of Scientific and Technical Information of China (English)

    Zhou Xun; Luo Zi-Jiang; Guo Xiang; Zhang Bi-Chan; Shang Lin-Tao; Zhou Qing; Deng Chao-Yong; Ding Zhao

    2012-01-01

    Surface segregation is studied via the evolution of reflection high-energy electron diffraction (RHEED) patterns under different values of As4 BEP for InGaAs films.When the As4 BEP is set to be zero,the RHEED pattern keeps a 4×3/(n×3) structure with increasing temperature,and surface segregation takes place until 470 ℃.The RHEED pattern develops into a metal-rich (4×2) structure as temperature increases to 495 ℃.The reason for this is that surface segregation makes the In inside the InGaAs film climb to its surface.With the temperature increasing up to 515 ℃,the RHEED pattern turns into a GaAs(2×4) structure due to In desorption.While the As4 BEP comes up to a specific value (1.33×10-4 Pa-1.33×10-3 Pa),the surface temperature can delay the segregation and desorption.We find that As4 BEP has a big influence on surface desorption,while surface segregation is more strongly dependent on temperature than surface desorption.

  8. Patterns of maximum body size evolution in Cenozoic land mammals: eco-evolutionary processes and abiotic forcing

    Science.gov (United States)

    Saarinen, Juha J.; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Evans, Alistair R.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Sibly, Richard M.; Stephens, Patrick R.; Theodor, Jessica; Uhen, Mark D.; Smith, Felisa A.

    2014-01-01

    There is accumulating evidence that macroevolutionary patterns of mammal evolution during the Cenozoic follow similar trajectories on different continents. This would suggest that such patterns are strongly determined by global abiotic factors, such as climate, or by basic eco-evolutionary processes such as filling of niches by specialization. The similarity of pattern would be expected to extend to the history of individual clades. Here, we investigate the temporal distribution of maximum size observed within individual orders globally and on separate continents. While the maximum size of individual orders of large land mammals show differences and comprise several families, the times at which orders reach their maximum size over time show strong congruence, peaking in the Middle Eocene, the Oligocene and the Plio-Pleistocene. The Eocene peak occurs when global temperature and land mammal diversity are high and is best explained as a result of niche expansion rather than abiotic forcing. Since the Eocene, there is a significant correlation between maximum size frequency and global temperature proxy. The Oligocene peak is not statistically significant and may in part be due to sampling issues. The peak in the Plio-Pleistocene occurs when global temperature and land mammal diversity are low, it is statistically the most robust one and it is best explained by global cooling. We conclude that the macroevolutionary patterns observed are a result of the interplay between eco-evolutionary processes and abiotic forcing. PMID:24741007

  9. Temporal and spatial evolution characteristics of gas-liquid two-phase flow pattern based on image texture spectrum descriptor

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xi-guo; JIN Ning-de; WANG Zhen-ya; ZHANG Wen-yin

    2009-01-01

    The dynamic image information of typical gas-liquid two-phase flow patterns in vertical upward pipe is captured by a high-speed dynamic camera. The texture spectrum descriptor is used to describe the texture characteristics of the processed images whose content is represented in the form of texture spectrum histogram, and four time-varying characteristic param-eter indexes which represent image texture structure of different flow patterns are extracted. The study results show that the amplitude fluctuation of texture characteristic parameter indexes of bubble flow is lowest and shows very random complex dynamic behavior; the amplitude fluctuation of slug flow is higher and shows intermittent motion behavior between gas slug and liquid slug, and the amplitude fluctuation of churn flow is the highest and shows better periodicity; the amplitude fluctuation of bubble-slug flow is from low to high and oscillating frequence is higher than that of slug flow, and includes the features of both slug flow and bubble flow; the slug-churn flow loses the periodicity of slug flow and churn flow, and the amplitude fluctuation is high. The results indicate that the image texture characteristic parameter indexes of different flow pattern can reflect the flow characteristics of gas-liquid two-phase flow, which provides a new approach to tmderstand the temporal and spatial evolution of flow pattern dynamics.

  10. A parallel splitting wavelet method for 2D conservation laws

    Science.gov (United States)

    Schmidt, Alex A.; Kozakevicius, Alice J.; Jakobsson, Stefan

    2016-06-01

    The current work presents a parallel formulation using the MPI protocol for an adaptive high order finite difference scheme to solve 2D conservation laws. Adaptivity is achieved at each time iteration by the application of an interpolating wavelet transform in each space dimension. High order approximations for the numerical fluxes are computed by ENO and WENO schemes. Since time evolution is made by a TVD Runge-Kutta space splitting scheme, the problem is naturally suitable for parallelization. Numerical simulations and speedup results are presented for Euler equations in gas dynamics problems.

  11. Hitting a BEC with a comb: Evolution of interference patterns inside a magnetic trap

    OpenAIRE

    Müller, J. H.; Morsch, O.; Cristiani, M.; Ciampini, D.; Arimondo, E.

    2002-01-01

    We study the evolution inside a harmonic trap of Bose-Einstein condensates released from the periodic potential of an optical lattice. After a time-of-flight, harmonic motion of the interference peaks is observed as well as a breathing motion in the direction perpendicular to the optical lattice. We interpret these results in terms of a simple physical model and discuss the possibility of more detailed studies of such a system.

  12. An Analysis of Evolution of Lending Patterns of IFAD China’s Rural Financial Project

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper tells us briefly the background and aims of the fundation of IFAD.It points out that IFAD plays an important part in helping the development of agriculture and food production in developing countries,and in reducing the poverty conditions in the poorest countries.It tells us that IFAD has offered donation to China for 8 times,with a total amount reaching to 56.839 million dollars.With the development of the economy of China,IFAD has changed its lending financial policies to China from a highly beneficial policy to a moderate lending policy.The operation of the loan projects have greatly improved the living conditions and of the local and the conditions of agricultural production,promoting the improvement of economy,social stability,and enviroment.It discusses several lending patterns of IFAD China’s rural financial projects.The government-leading model,which is represented by the IFAD financial lending loan.Market-oriented model of formal financial institutions,which is represented by IFAD Rural Credit Cooperatives,with market oriented.Government supporting as secondary model,which are dominated by IFAD Women’s lending patterns and Village Development Fund lending model.In this paper,advantages and disadvantages of lending patterns are analyzed and evaluated.It discusses the development trend of IFAD financial lending patterns in terms of Rural Credit Cooperatives and a pattern which is community-oriented and farmers-benefited.

  13. Bees, birds and yellow flowers: pollinator-dependent convergent evolution of UV patterns.

    Science.gov (United States)

    Papiorek, S; Junker, R R; Alves-Dos-Santos, I; Melo, G A R; Amaral-Neto, L P; Sazima, M; Wolowski, M; Freitas, L; Lunau, K

    2016-01-01

    Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among the angiosperms. Flower colour is responsible for attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UV- absorbing. In choice experiments we found that bees did not show consistent preferences for any colour or pattern types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower, irrespective of its spatial position within the flower. The appearance of UV patterns within flowers is the main difference in spectral reflectance between yellow bee- and bird-pollinated flowers, and affects the foraging behaviour of flower visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other.

  14. Seepage Analysis of Upper Gotvand Dam Concerning Gypsum Karstification (2D and 3D Approaches)

    DEFF Research Database (Denmark)

    Sadrekarimi, Jamshid; Kiyani, Majid; Fakhri, Behnam;

    2011-01-01

    Upper Gotvand Dam is constructed on the Karun River at the south west of Iran. In this paper, 2D and 3D models of the dam together with the foundation and abutments were established, and several seepage analyses were carried out. Then, the gypsum veins that are scattered throughout the foundation...... model locates the phreatic surface somewhat higher than the 2D model. This means that the 2D model estimates lower pore water pressure pattern in comparison with the 3D model. These may be attributed to the fact that with 2D model the lateral components of vectors of seepage velocity are ignored...... flux through the foundation ground....

  15. DNA aneuploidy as a topographic malignant transformation pattern in a pleomorphic adenoma of long-term evolution: a case report

    Directory of Open Access Journals (Sweden)

    Gallego Lorena

    2011-11-01

    Full Text Available Abstract Introduction We present a case of long-term evolution of a submandibular pleomorphic adenoma. There is little information about topographic malignant transformation patterns of pleomorphic adenomas. Case presentation We extensively analyze a giant submandibular mixed tumor of 25-year evolution in a 57-year-old Caucasian woman. Deoxyribonucleic acid ploidy was evaluated in different superficial and deep areas using flow cytometry analysis and correlated with pathological and immunohistochemical characteristics. Superficial areas exhibited a typical histological pleomorphic adenoma pattern and were deoxyribonucleic acid diploid. Deep samples showed deoxyribonucleic acid aneuploidy, atypical histological benign features and expression of markers involved at an early-stage of malignant transformation, such as tumor protein 53 and antigen Ki67. Conclusion These findings revealed that deep tumor compartments may be involved in the initial stages of malignant transformation. Deoxyribonucleic acid ploidy analysis may provide an additional diagnosis tool and indicate 'uncertain' areas that require careful study to avoid diagnostic errors. Larger studies are needed to confirm our results and to evaluate the usefulness of the technique.

  16. Multi-Input Single Output SSSC based damping controller design by a hybrid Improved Differential Evolution-Pattern Search approach.

    Science.gov (United States)

    Panda, Sidhartha; Yegireddy, Narendra Kumar

    2015-09-01

    In this paper, a hybrid Improved Differential Evolution and Pattern Search (hIDEPS) approach is proposed for the design of a PI-Type Multi-Input Single Output (MISO) Static Synchronous Series Compensator (SSSC) based damping controller. The improvement in Differential Evolution (DE) algorithm is introduced by a simple but effective scheme of changing two of its most important control parameters i.e. step size and crossover probability with an objective of achieving improved performance. Pattern Search (PS) is subsequently employed to fine tune the best solution provided by modified DE algorithm. The superiority of a proposed hIDEPS technique over DE and improved DE has also been demonstrated. At the outset, this concept is applied to a SSSC connected in a Single Machine Infinite Bus (SMIB) power system and then extended to a multi-machine power system. To show the effectiveness and robustness of the proposed design approach, simulation results are presented and compared with DE and Particle Swarm Optimization (PSO) optimized Single Input Single Output (SISO) SSSC based damping controllers. It is observed that the proposed approach yield superior damping performance compared to some approaches available in the literature. PMID:25864132

  17. Multi-Input Single Output SSSC based damping controller design by a hybrid Improved Differential Evolution-Pattern Search approach.

    Science.gov (United States)

    Panda, Sidhartha; Yegireddy, Narendra Kumar

    2015-09-01

    In this paper, a hybrid Improved Differential Evolution and Pattern Search (hIDEPS) approach is proposed for the design of a PI-Type Multi-Input Single Output (MISO) Static Synchronous Series Compensator (SSSC) based damping controller. The improvement in Differential Evolution (DE) algorithm is introduced by a simple but effective scheme of changing two of its most important control parameters i.e. step size and crossover probability with an objective of achieving improved performance. Pattern Search (PS) is subsequently employed to fine tune the best solution provided by modified DE algorithm. The superiority of a proposed hIDEPS technique over DE and improved DE has also been demonstrated. At the outset, this concept is applied to a SSSC connected in a Single Machine Infinite Bus (SMIB) power system and then extended to a multi-machine power system. To show the effectiveness and robustness of the proposed design approach, simulation results are presented and compared with DE and Particle Swarm Optimization (PSO) optimized Single Input Single Output (SISO) SSSC based damping controllers. It is observed that the proposed approach yield superior damping performance compared to some approaches available in the literature.

  18. 2d Index and Surface operators

    CERN Document Server

    Gadde, Abhijit

    2013-01-01

    In this paper we compute the superconformal index of 2d (2,2) supersymmetric gauge theories. The 2d superconformal index, a.k.a. flavored elliptic genus, is computed by a unitary matrix integral much like the matrix integral that computes 4d superconformal index. We compute the 2d index explicitly for a number of examples. In the case of abelian gauge theories we see that the index is invariant under flop transition and CY-LG correspondence. The index also provides a powerful check of the Seiberg-type duality for non-abelian gauge theories discovered by Hori and Tong. In the later half of the paper, we study half-BPS surface operators in N=2 superconformal gauge theories. They are engineered by coupling the 2d (2,2) supersymmetric gauge theory living on the support of the surface operator to the 4d N=2 theory, so that different realizations of the same surface operator with a given Levi type are related by a 2d analogue of the Seiberg duality. The index of this coupled system is computed by using the tools de...

  19. Domestication and the mitochondrial genome: comparing patterns and rates of molecular evolution in domesticated mammals and birds and their wild relatives.

    Science.gov (United States)

    Moray, Camile; Lanfear, Robert; Bromham, Lindell

    2014-01-01

    Studies of domesticated animals have led to the suggestion that domestication could have significant effects on patterns of molecular evolution. In particular, analyses of mitochondrial genome sequences from domestic dogs and yaks have yielded higher ratios of non-synonymous to synonymous substitutions in the domesticated lineages than in their wild relatives. These results are important because they imply that changes to selection or population size operating over a short timescale can cause significant changes to the patterns of mitochondrial molecular evolution. In this study, our aim is to test whether the impact on mitochondrial genome evolution is a general feature of domestication or whether it is specific to particular examples. We test whether domesticated mammals and birds have consistently different patterns of molecular evolution than their wild relatives for 16 phylogenetically independent comparisons of mitochondrial genome sequences. We find no consistent difference in branch lengths or dN/dS between domesticated and wild lineages. We also find no evidence that our failure to detect a consistent pattern is due to the short timescales involved or low genetic distance between domesticated lineages and their wild relatives. However, removing comparisons where the wild relative may also have undergone a bottleneck does reveal a pattern consistent with reduced effective population size in domesticated lineages. Our results suggest that, although some domesticated lineages may have undergone changes to selective regime or effective population size that could have affected mitochondrial evolution, it is not possible to generalize these patterns over all domesticated mammals and birds.

  20. Clinicopathogenomic analysis of mismatch repair proficient colorectal adenocarcinoma uncovers novel prognostic subgroups with differing patterns of genetic evolution.

    Science.gov (United States)

    Braxton, David R; Zhang, Ray; Morrissette, Jennifer D; Loaiza-Bonilla, Arturo; Furth, Emma E

    2016-10-01

    Cancer somatic genetic evolution is a direct contributor to heterogeneity at the clonal and molecular level in colorectal adenocarcinoma (COAD). We sought to determine the extent to which genetic evolution may be detected in COAD in routinely obtained single clinical specimens and establish clinical significance with regard to clinicopathologic and outcome data. One hundred and twenty three cases of routinely collected mismatch repair proficient COAD were sequenced on the Illumina Truseq Amplicon assay. Measures of intratumoral heterogeneity and the preferential timing of mutational events were assessed and compared to clinicopathologic data. Survival subanalysis was performed on 55 patients. Patient age (p = 0.013) and specimen percent tumor (p = 0.033) was associated with clonal diversity, and biopsy (p = 0.044) and metastasis (p = 0.044) returned fewer mutations per case. APC and TP53 mutations preferentially occurred early while alterations in FBXW7, FLT3, SMAD4, GNAS and PTEN preferentially occurred as late events. Temporal heterogeneity was evident in KRAS and PIK3CA mutations. Hierarchical clustering revealed a TP53 mutant subtype and a MAPK-PIK3CA subtype with differing patterns of late mutational events. Survival subanalysis showed a decreased median progression free survival for the MAPK-PIK3CA subtype (8 months vs. 13 months; univariate logrank p = 0.0380, cox model p= 0.018). Neoadjuvant therapy associated mutations were found for ERBB2 (p = 0.0481) and FBXW7 (p = 0.015). Our data indicate novel molecular subtypes of mismatch repair proficient COAD display differing patterns of genetic evolution which correlate with clinical outcomes. Furthermore, we report treatment acquired and/or selected mutations in ERBB2 and FBXW7. PMID:27194209

  1. Optical modulators with 2D layered materials

    Science.gov (United States)

    Sun, Zhipei; Martinez, Amos; Wang, Feng

    2016-04-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.

  2. Automatic Contour Extraction from 2D Image

    Directory of Open Access Journals (Sweden)

    Panagiotis GIOANNIS

    2011-03-01

    Full Text Available Aim: To develop a method for automatic contour extraction from a 2D image. Material and Method: The method is divided in two basic parts where the user initially chooses the starting point and the threshold. Finally the method is applied to computed tomography of bone images. Results: An interesting method is developed which can lead to a successful boundary extraction of 2D images. Specifically data extracted from a computed tomography images can be used for 2D bone reconstruction. Conclusions: We believe that such an algorithm or part of it can be applied on several other applications for shape feature extraction in medical image analysis and generally at computer graphics.

  3. 2D microwave imaging reflectometer electronics

    Energy Technology Data Exchange (ETDEWEB)

    Spear, A. G.; Domier, C. W., E-mail: cwdomier@ucdavis.edu; Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C. [Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  4. Evolution of stationary wave patterns in mesospheric water vapor due to climate change

    Science.gov (United States)

    Demirhan Barı, Deniz; Gabriel, Axel; Sezginer Ünal, Yurdanur

    2016-07-01

    The variability in the observed stationary wave patterns of the mesospheric water vapor (H2O) is investigated using CMIP5 RCP 4.5 and RCP 8.5 projections. The change in the vertical and meridional wave structure at northern mid- and polar latitudes associated to the zonal and meridional eddy heat fluxes is discussed by analyzing the advection of H2O due to residual wind components. The alteration in the characteristics of the stationary wave-1 pattern of the lower mesospheric H2O (up to about 75km) related to change in the projected radiative forcing is observed for the years from 2006 to 2100. Additionally the remarkable effect of the increase in global temperature on the zonal asymmetries in small-scale transient waves and parameterized gravity waves, which largely contribute to the observed stationary wave patterns of H2O in the upper mesosphere, is analyzed. For validation purposes, the derived stratospheric patterns are verified against the eddy heat fluxes and residual advection terms derived from Aura/MLS satellite data between 2004-2010 and the reference period of the CMIP5 MPI dataset (1976-2005) providing confidence in the applied method.

  5. Strain localization band width evolution by electronic speckle pattern interferometry strain rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Guelorget, Bruno [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)], E-mail: bruno.guelorget@utt.fr; Francois, Manuel; Montay, Guillaume [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

    2009-04-15

    In this paper, electronic speckle pattern interferometry strain rate measurements are used to quantify the width of the strain localization band, which occurs when a sheet specimen is submitted to tension. It is shown that the width of this band decreases with increasing strain. Just before fracture, this measured width is about five times wider than the shear band and the initial sheet thickness.

  6. A comparative physical map reveals the pattern of chromosomal evolution between the turkey (Meleagris gallopavo and chicken (Gallus gallus genomes

    Directory of Open Access Journals (Sweden)

    Delany Mary E

    2011-09-01

    Full Text Available Abstract Background A robust bacterial artificial chromosome (BAC-based physical map is essential for many aspects of genomics research, including an understanding of chromosome evolution, high-resolution genome mapping, marker-assisted breeding, positional cloning of genes, and quantitative trait analysis. To facilitate turkey genetics research and better understand avian genome evolution, a BAC-based integrated physical, genetic, and comparative map was developed for this important agricultural species. Results The turkey genome physical map was constructed based on 74,013 BAC fingerprints (11.9 × coverage from two independent libraries, and it was integrated with the turkey genetic map and chicken genome sequence using over 41,400 BAC assignments identified by 3,499 overgo hybridization probes along with > 43,000 BAC end sequences. The physical-comparative map consists of 74 BAC contigs, with an average contig size of 13.6 Mb. All but four of the turkey chromosomes were spanned on this map by three or fewer contigs, with 14 chromosomes spanned by a single contig and nine chromosomes spanned by two contigs. This map predicts 20 to 27 major rearrangements distinguishing turkey and chicken chromosomes, despite up to 40 million years of separate evolution between the two species. These data elucidate the chromosomal evolutionary pattern within the Phasianidae that led to the modern turkey and chicken karyotypes. The predominant rearrangement mode involves intra-chromosomal inversions, and there is a clear bias for these to result in centromere locations at or near telomeres in turkey chromosomes, in comparison to interstitial centromeres in the orthologous chicken chromosomes. Conclusion The BAC-based turkey-chicken comparative map provides novel insights into the evolution of avian genomes, a framework for assembly of turkey whole genome shotgun sequencing data, and tools for enhanced genetic improvement of these important agricultural and

  7. Design of Spiking Central Pattern Generators for Multiple Locomotion Gaits in Hexapod Robots by Christiansen Grammar Evolution.

    Science.gov (United States)

    Espinal, Andres; Rostro-Gonzalez, Horacio; Carpio, Martin; Guerra-Hernandez, Erick I; Ornelas-Rodriguez, Manuel; Sotelo-Figueroa, Marco

    2016-01-01

    This paper presents a method to design Spiking Central Pattern Generators (SCPGs) to achieve locomotion at different frequencies on legged robots. It is validated through embedding its designs into a Field-Programmable Gate Array (FPGA) and implemented on a real hexapod robot. The SCPGs are automatically designed by means of a Christiansen Grammar Evolution (CGE)-based methodology. The CGE performs a solution for the configuration (synaptic weights and connections) for each neuron in the SCPG. This is carried out through the indirect representation of candidate solutions that evolve to replicate a specific spike train according to a locomotion pattern (gait) by measuring the similarity between the spike trains and the SPIKE distance to lead the search to a correct configuration. By using this evolutionary approach, several SCPG design specifications can be explicitly added into the SPIKE distance-based fitness function, such as looking for Spiking Neural Networks (SNNs) with minimal connectivity or a Central Pattern Generator (CPG) able to generate different locomotion gaits only by changing the initial input stimuli. The SCPG designs have been successfully implemented on a Spartan 6 FPGA board and a real time validation on a 12 Degrees Of Freedom (DOFs) hexapod robot is presented.

  8. Structural patterns, evolution, and seismic expression of Montague County, Texas - Implications concerning past discoveries and future exploration

    Energy Technology Data Exchange (ETDEWEB)

    Font, R.G. (Strategic Petroleum, Inc., Dallas, TX (USA))

    1990-02-01

    North Texas is a mature province that has yielded abundant hydrocarbons. Opportunities still exist for discovering large reserves by applying new technology and developing innovative concepts for frontier type plays. Montague County can be used to illustrate this point. Analysis of seismic and petrologic data reveals a fascinating scenario concerning structural patterns and tectonic evolution. The Proterozoic and early Paleozoic history is related to the development of the Wichita aulacogen. Similar structural architecture is found on the southern side of the Wichita-Amarillo uplift from the Hardeman basin to Montague County. The early history reflects rifting. Subsequent tectonism relates to the Hercynian orogeny, plate convergence, and collision. Fault patterns mapped from seismic and subsurface data may be explained through reorientation of the principal stresses. Of the major patterns mapped, the northwest-trending system is dominant. Normal faults formed during rifting were selectively reactivated as upthrusts during convergence. Past discoveries are almost invariably related to seismic expression. New Carboniferous reserves will be discovered in subtle traps. State-of-the-art seismic and seismic stratigraphy will equate to exploratory success. New play concepts involve the petroleum potential of the deep Ellenburger, similar to the deep pay found in Oklahoma. Recent deep wells drilled in the county affirm the presence of structure and reservoir, but fail to find the indigenous source potential present north of the Red River. Best opportunities for deep Ellenburger discoveries in Texas lie where faulting juxtaposes Carboniferous source rocks to the Cambrian-Ordovician reservoirs.

  9. Design of Spiking Central Pattern Generators for Multiple Locomotion Gaits in Hexapod Robots by Christiansen Grammar Evolution

    Science.gov (United States)

    Espinal, Andres; Rostro-Gonzalez, Horacio; Carpio, Martin; Guerra-Hernandez, Erick I.; Ornelas-Rodriguez, Manuel; Sotelo-Figueroa, Marco

    2016-01-01

    This paper presents a method to design Spiking Central Pattern Generators (SCPGs) to achieve locomotion at different frequencies on legged robots. It is validated through embedding its designs into a Field-Programmable Gate Array (FPGA) and implemented on a real hexapod robot. The SCPGs are automatically designed by means of a Christiansen Grammar Evolution (CGE)-based methodology. The CGE performs a solution for the configuration (synaptic weights and connections) for each neuron in the SCPG. This is carried out through the indirect representation of candidate solutions that evolve to replicate a specific spike train according to a locomotion pattern (gait) by measuring the similarity between the spike trains and the SPIKE distance to lead the search to a correct configuration. By using this evolutionary approach, several SCPG design specifications can be explicitly added into the SPIKE distance-based fitness function, such as looking for Spiking Neural Networks (SNNs) with minimal connectivity or a Central Pattern Generator (CPG) able to generate different locomotion gaits only by changing the initial input stimuli. The SCPG designs have been successfully implemented on a Spartan 6 FPGA board and a real time validation on a 12 Degrees Of Freedom (DOFs) hexapod robot is presented. PMID:27516737

  10. Origins of anteroposterior patterning and Hox gene regulation during chordate evolution.

    OpenAIRE

    Schilling, T. F.; Knight, R D

    2001-01-01

    All chordates share a basic body plan and many common features of early development. Anteroposterior (AP) regions of the vertebrate neural tube are specified by a combinatorial pattern of Hox gene expression that is conserved in urochordates and cephalochordates. Another primitive feature of Hox gene regulation in all chordates is a sensitivity to retinoic acid during embryogenesis, and recent developmental genetic studies have demonstrated the essential role for retinoid signalling in verteb...

  11. Interface dynamics under nonequilibrium conditions: from a self-propelled droplet to dynamic pattern evolution

    CERN Document Server

    Chen, Yong-Jun

    2012-01-01

    In this article, we describe the instability of a contact line under nonequilibrium conditions mainly based on the results of our recent studies. Two experimental examples are presented: the self-propelled motion of a liquid droplet and spontaneous dynamic pattern formation. For the self-propelled motion of a droplet, we introduce an experiment in which a droplet of aniline sitting on an aqueous layer moves spontaneously at an air-water interface. The spontaneous symmetry breaking of Marangoni-driven spreading causes regular motion. In a circular Petri dish, the droplet exhibits either beeline motion or circular motion. On the other hand, we show the emergence of a dynamic labyrinthine pattern caused by dewetting of a metastable thin film from the air-water interface. The contact line between the organic phase and aqueous phase forms a unique spatio-temporal pattern characterized as a dynamic labyrinthine. Motion of the contact line is controlled by diffusion processes. We propose a theoretical model to inter...

  12. Differences in the selection response of serially repeated color pattern characters: Standing variation, development, and evolution

    Directory of Open Access Journals (Sweden)

    Zwaan Bas J

    2008-03-01

    Full Text Available Abstract Background There is spectacular morphological diversity in nature but lineages typically display a limited range of phenotypes. Because developmental processes generate the phenotypic variation that fuels natural selection, they are a likely source of evolutionary biases, facilitating some changes and limiting others. Although shifts in developmental regulation are associated with morphological differences between taxa, it is unclear how underlying mechanisms affect the rate and direction of evolutionary change within populations under selection. Here we focus on two ecologically relevant features of butterfly wing color patterns, eyespot size and color composition, which are similarly and strongly correlated across the serially repeated eyespots. Though these two characters show similar patterns of standing variation and covariation within a population, they differ in key features of their underlying development. We targeted pairs of eyespots with artificial selection for coordinated (concerted selection versus independent (antagonistic selection change in their color composition and size and compared evolutionary responses of the two color pattern characters. Results The two characters respond to selection in strikingly different ways despite initially similar patterns of variation in all directions present in the starting population. Size (determined by local properties of a diffusing inductive signal evolves flexibly in all selected directions. However, color composition (determined by a tissue-level response to the signal concentration gradient evolves only in the direction of coordinated change. There was no independent evolutionary change in the color composition of two eyespots in response to antagonistic selection. Moreover, these differences in the directions of short-term evolutionary change in eyespot size and color composition within a single species are consistent with the observed wing pattern diversity in the genus

  13. Horns Rev II, 2-D Model Tests

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Frigaard, Peter

    This report present the results of 2D physical model tests carried out in the shallow wave flume at Dept. of Civil Engineering, Aalborg University (AAU), on behalf of Energy E2 A/S part of DONG Energy A/S, Denmark. The objective of the tests was: to investigate the combined influence of the pile...

  14. 2D PIM Simulation Based on COMSOL

    DEFF Research Database (Denmark)

    Wang, Xinbo; Cui, Wanzhao; Wang, Jingyu;

    2011-01-01

    Passive intermodulation (PIM) is a problematic type of nonlinear distortion en- countered in many communication systems. To analyze the PIM distortion resulting from ma- terial nonlinearity, a 2D PIM simulation method based on COMSOL is proposed in this paper. As an example, a rectangular waveguide...

  15. Baby universes in 2d quantum gravity

    OpenAIRE

    Ambjorn, J.; S. Jain; G. Thorleifsson

    1993-01-01

    We investigate the fractal structure of $2d$ quantum gravity, both for pure gravity and for gravity coupled to multiple gaussian fields and for gravity coupled to Ising spins. The roughness of the surfaces is described in terms of baby universes and using numerical simulations we measure their distribution which is related to the string susceptibility exponent $\\g_{string}$.

  16. Homoplasy: from detecting pattern to determining process and mechanism of evolution.

    Science.gov (United States)

    Wake, David B; Wake, Marvalee H; Specht, Chelsea D

    2011-02-25

    Understanding the diversification of phenotypes through time--"descent with modification"--has been the focus of evolutionary biology for 150 years. If, contrary to expectations, similarity evolves in unrelated taxa, researchers are guided to uncover the genetic and developmental mechanisms responsible. Similar phenotypes may be retained from common ancestry (homology), but a phylogenetic context may instead reveal that they are independently derived, due to convergence or parallel evolution, or less likely, that they experienced reversal. Such examples of homoplasy present opportunities to discover the foundations of morphological traits. A common underlying mechanism may exist, and components may have been redeployed in a way that produces the "same" phenotype. New, robust phylogenetic hypotheses and molecular, genomic, and developmental techniques enable integrated exploration of the mechanisms by which similarity arises.

  17. Homoplasy: from detecting pattern to determining process and mechanism of evolution.

    Science.gov (United States)

    Wake, David B; Wake, Marvalee H; Specht, Chelsea D

    2011-02-25

    Understanding the diversification of phenotypes through time--"descent with modification"--has been the focus of evolutionary biology for 150 years. If, contrary to expectations, similarity evolves in unrelated taxa, researchers are guided to uncover the genetic and developmental mechanisms responsible. Similar phenotypes may be retained from common ancestry (homology), but a phylogenetic context may instead reveal that they are independently derived, due to convergence or parallel evolution, or less likely, that they experienced reversal. Such examples of homoplasy present opportunities to discover the foundations of morphological traits. A common underlying mechanism may exist, and components may have been redeployed in a way that produces the "same" phenotype. New, robust phylogenetic hypotheses and molecular, genomic, and developmental techniques enable integrated exploration of the mechanisms by which similarity arises. PMID:21350170

  18. The mind of primitive anthropologists: hemoglobin and HLA, patterns of molecular evolution.

    Science.gov (United States)

    Williams, Robert C

    2003-08-01

    Frank Livingstone played a central role in defining the population genetics of the sickle cell mutation at position 6 of the human beta globin gene, the most famous amino acid substitution in evolutionary biology. Its discovery occurred at a time when traditional, 19th-century principles of natural selection were being joined with the newly discovered mechanics of DNA structure and protein synthesis to produce Neo-Darwinian theory. When combined with the epidemiology of malaria in Africa, differential mortality for both homozygotes, and the resulting advantage of the heterozygote, sickle cell became the classic balanced polymorphism. Human HLA-A has 237 molecular alleles. The histocompatibility system has as its primary function the presentation of peptides to T-cell receptors and plays an essential role in the immune system. Nearly all of the alleles are codominant and fully functional. Despite almost 30 years of disease-association studies with HLA-A, no convincing evidence has been found for differential fertility or mortality at this locus. Yet the dogma in the histocompatibility field is that this extensive human polymorphism is maintained by "balancing selection." Explaining HLA-A polymorphism is what one might call the sickle-cell-effect. This one mutation, coming as it did at the historical convergence of Darwinian theory and modern genetics, and carrying with it the strong relationship between mutation, disease, and allele frequency, has conditioned our discussion of human genetic variation and population genetics. Has the strength of this early idea made evolutionary biologists uncritical of systems like HLA-A and retarded the search for new mechanisms of molecular evolution? Is it now time to move away from a focus on mutation and polymorphism in evolutionary genetics and toward a systems theory that would explain the origin and evolution of hemoglobin and HLA-A and the biochemical pathways that surround them?

  19. Evolution of Xylan Substitution Patterns in Gymnosperms and Angiosperms: Implications for Xylan Interaction with Cellulose.

    Science.gov (United States)

    Busse-Wicher, Marta; Li, An; Silveira, Rodrigo L; Pereira, Caroline S; Tryfona, Theodora; Gomes, Thiago C F; Skaf, Munir S; Dupree, Paul

    2016-08-01

    The interaction between cellulose and xylan is important for the load-bearing secondary cell wall of flowering plants. Based on the precise, evenly spaced pattern of acetyl and glucuronosyl (MeGlcA) xylan substitutions in eudicots, we recently proposed that an unsubstituted face of xylan in a 2-fold helical screw can hydrogen bond to the hydrophilic surfaces of cellulose microfibrils. In gymnosperm cell walls, any role for xylan is unclear, and glucomannan is thought to be the important cellulose-binding polysaccharide. Here, we analyzed xylan from the secondary cell walls of the four gymnosperm lineages (Conifer, Gingko, Cycad, and Gnetophyta). Conifer, Gingko, and Cycad xylan lacks acetylation but is modified by arabinose and MeGlcA. Interestingly, the arabinosyl substitutions are located two xylosyl residues from MeGlcA, which is itself placed precisely on every sixth xylosyl residue. Notably, the Gnetophyta xylan is more akin to early-branching angiosperms and eudicot xylan, lacking arabinose but possessing acetylation on alternate xylosyl residues. All these precise substitution patterns are compatible with gymnosperm xylan binding to hydrophilic surfaces of cellulose. Molecular dynamics simulations support the stable binding of 2-fold screw conifer xylan to the hydrophilic face of cellulose microfibrils. Moreover, the binding of multiple xylan chains to adjacent planes of the cellulose fibril stabilizes the interaction further. Our results show that the type of xylan substitution varies, but an even pattern of xylan substitution is maintained among vascular plants. This suggests that 2-fold screw xylan binds hydrophilic faces of cellulose in eudicots, early-branching angiosperm, and gymnosperm cell walls. PMID:27325663

  20. 工作团队研究模式的演进%Evolution of Research Patterns of Work Team

    Institute of Scientific and Technical Information of China (English)

    薛继东

    2011-01-01

    从工作团队定义、分类入手,对已有工作团队研究成果进行归纳总结,指出工作团队研究主要经历三种递进模式:IPO、IMO和IMOI,这三种研究模式的演进体现了团队研究复杂、动态、适应和循环的特征,并为未来的团队研究提出建议.%Starting from the definition and types of work teams, the article summarizes three kinds of evolutionary patterns of work team research: IPO, IMO, IMOI. The evolution reflects four characteristics of work team research: complex, dynamic, adaptive and cycling. The article also concludes briefly emerging directions in work team research.

  1. Three-dimensional effects in directional solidification in hele-shaw cells: nonlinear evolution and pattern selection

    Science.gov (United States)

    Ajaev; Davis

    2000-02-01

    Directional solidification of a dilute binary alloy in a Hele-Shaw cell is modeled by a long-wave nonlinear evolution equation with zero flux and contact-angle conditions at the walls. The basic steady-state solution and its linear stability criteria are found analytically, and the nonlinear system is solved numerically. Concave-down (toward the solid) interfaces under physically realistic conditions are found to be more unstable than the planar front. Weakly nonlinear analysis indicates that subcritical bifurcation is promoted, the domain of modulational instability is expanded and transition to three-dimensional patterns is delayed due to the contact-angle condition. In the strongly nonlinear regime fully three-dimensional steady-state solutions are found whose characteristic amplitude is larger than that for the two-dimensional problem. In the subcritical regime secondary bifurcation to stable solutions is promoted.

  2. Size Evolution of Ordered SiGe Islands Grown by Surface Thermal Diffusion on Pit-Patterned Si(100 Surface

    Directory of Open Access Journals (Sweden)

    Bollani Monica

    2010-01-01

    Full Text Available Abstract The ordered growth of self-assembled SiGe islands by surface thermal diffusion in ultra high vacuum from a lithographically etched Ge stripe on pit-patterned Si(100 surface has been experimentally investigated. The total surface coverage of Ge strongly depends on the distance from the source stripe, as quantitatively verified by Scanning Auger Microscopy. The size distribution of the islands as a function of the Ge coverage has been studied by coupling atomic force microscopy scans with Auger spectro-microscopy data. Our observations are consistent with a physical scenario where island positioning is essentially driven by energetic factors, which predominate with respect to the local kinetics of diffusion, and the growth evolution mainly depends on the local density of Ge atoms.

  3. Positron beam optics for the 2D-ACAR spectrometer at the NEPOMUC beamline

    International Nuclear Information System (INIS)

    In the last year a conventional 2D-ACAR spectrometer has been set up and brought to operation at TUM. Once the NEPOMUC beamline is extended to the new experimental hall at the research reactor FRM-II the conventional 2D-ACAR spectrometer will be upgraded with a second sample chamber in order to be integrated to the NEPOMUC beamline facility. This spectrometer will add a complete new quality to 2D-ACAR experiments as it allows to track the evolution of the electronic structure from the surface to the bulk. We present the design features of the positron beam optics and the sample environment.

  4. Positron beam optics for the 2D-ACAR spectrometer at the NEPOMUC beamline

    Science.gov (United States)

    Ceeh, H.; Weber, J. A.; Hugenschmidt, C.; Leitner, M.; Boni, P.

    2014-04-01

    In the last year a conventional 2D-ACAR spectrometer has been set up and brought to operation at TUM. Once the NEPOMUC beamline is extended to the new experimental hall at the research reactor FRM-II the conventional 2D-ACAR spectrometer will be upgraded with a second sample chamber in order to be integrated to the NEPOMUC beamline facility. This spectrometer will add a complete new quality to 2D-ACAR experiments as it allows to track the evolution of the electronic structure from the surface to the bulk. We present the design features of the positron beam optics and the sample environment.

  5. The nocturnal bottleneck and the evolution of activity patterns in mammals.

    Science.gov (United States)

    Gerkema, Menno P; Davies, Wayne I L; Foster, Russell G; Menaker, Michael; Hut, Roelof A

    2013-08-22

    In 1942, Walls described the concept of a 'nocturnal bottleneck' in placental mammals, where these species could survive only by avoiding daytime activity during times in which dinosaurs were the dominant taxon. Walls based this concept of a longer episode of nocturnality in early eutherian mammals by comparing the visual systems of reptiles, birds and all three extant taxa of the mammalian lineage, namely the monotremes, marsupials (now included in the metatherians) and placentals (included in the eutherians). This review describes the status of what has become known as the nocturnal bottleneck hypothesis, giving an overview of the chronobiological patterns of activity. We review the ecological plausibility that the activity patterns of (early) eutherian mammals were restricted to the night, based on arguments relating to endothermia, energy balance, foraging and predation, taking into account recent palaeontological information. We also assess genes, relating to light detection (visual and non-visual systems) and the photolyase DNA protection system that were lost in the eutherian mammalian lineage. Our conclusion presently is that arguments in favour of the nocturnal bottleneck hypothesis in eutherians prevail.

  6. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    Science.gov (United States)

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-02-06

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  7. Phylogenetic Patterns of Codon Evolution in the ACTIN-DEPOLYMERIZING FACTOR/COFILIN (ADF/CFL Gene Family.

    Directory of Open Access Journals (Sweden)

    Eileen M Roy-Zokan

    Full Text Available The actin-depolymerizing factor/cofilin (ADF/CFL gene family encodes a diverse group of relatively small proteins. Once known strictly as modulators of actin filament dynamics, recent research has demonstrated that these proteins are involved in a variety of cellular processes, from signal transduction to the cytonuclear trafficking of actin. In both plant and animal lineages, expression patterns of paralogs in the ADF/CFL gene family vary among tissue types and developmental stages. In this study we use computational approaches to investigate the evolutionary forces responsible for the diversification of the ADF/CFL gene family. Estimating the rate of non-synonymous to synonymous mutations (dN/dS across phylogenetic lineages revealed that the majority of ADF/CFL codon positions were under strong purifying selection, with rare episodic events of accelerated protein evolution. In both plants and animals these instances of accelerated evolution were ADF/CFL subclass specific, and all of the sites under selection were located in regions of the protein that could serve in new functional roles. We suggest these sites may have been important in the functional diversification of ADF/CFL proteins.

  8. Design Application Translates 2-D Graphics to 3-D Surfaces

    Science.gov (United States)

    2007-01-01

    Fabric Images Inc., specializing in the printing and manufacturing of fabric tension architecture for the retail, museum, and exhibit/tradeshow communities, designed software to translate 2-D graphics for 3-D surfaces prior to print production. Fabric Images' fabric-flattening design process models a 3-D surface based on computer-aided design (CAD) specifications. The surface geometry of the model is used to form a 2-D template, similar to a flattening process developed by NASA's Glenn Research Center. This template or pattern is then applied in the development of a 2-D graphic layout. Benefits of this process include 11.5 percent time savings per project, less material wasted, and the ability to improve upon graphic techniques and offer new design services. Partners include Exhibitgroup/Giltspur (end-user client: TAC Air, a division of Truman Arnold Companies Inc.), Jack Morton Worldwide (end-user client: Nickelodeon), as well as 3D Exhibits Inc., and MG Design Associates Corp.

  9. Lack of low frequency variants masks patterns of non-neutral evolution following domestication.

    Directory of Open Access Journals (Sweden)

    Céline H Frère

    Full Text Available Detecting artificial selection in the genome of domesticated species can not only shed light on human history but can also be beneficial to future breeding strategies. Evidence for selection has been documented in domesticated species including maize and rice, but few studies have to date detected signals of artificial selection in the Sorghum bicolor genome. Based on evidence that domesticated S. bicolor and its wild relatives show significant differences in endosperm structure and quality, we sequenced three candidate seed storage protein (kafirin loci and three candidate starch biosynthesis loci to test whether these genes show non-neutral evolution resulting from the domestication process. We found strong evidence of non-neutral selection at the starch synthase IIa gene, while both starch branching enzyme I and the beta kafirin gene showed weaker evidence of non-neutral selection. We argue that the power to detect consistent signals of non-neutral selection in our dataset is confounded by the absence of low frequency variants at four of the six candidate genes. A future challenge in the detection of positive selection associated with domestication in sorghum is to develop models that can accommodate for skewed frequency spectrums.

  10. Lack of low frequency variants masks patterns of non-neutral evolution following domestication.

    Science.gov (United States)

    Frère, Céline H; Prentis, Peter J; Gilding, Edward K; Mudge, Agnieszka M; Cruickshank, Alan; Godwin, Ian D

    2011-01-01

    Detecting artificial selection in the genome of domesticated species can not only shed light on human history but can also be beneficial to future breeding strategies. Evidence for selection has been documented in domesticated species including maize and rice, but few studies have to date detected signals of artificial selection in the Sorghum bicolor genome. Based on evidence that domesticated S. bicolor and its wild relatives show significant differences in endosperm structure and quality, we sequenced three candidate seed storage protein (kafirin) loci and three candidate starch biosynthesis loci to test whether these genes show non-neutral evolution resulting from the domestication process. We found strong evidence of non-neutral selection at the starch synthase IIa gene, while both starch branching enzyme I and the beta kafirin gene showed weaker evidence of non-neutral selection. We argue that the power to detect consistent signals of non-neutral selection in our dataset is confounded by the absence of low frequency variants at four of the six candidate genes. A future challenge in the detection of positive selection associated with domestication in sorghum is to develop models that can accommodate for skewed frequency spectrums.

  11. Episode-Based Evolution Pattern Analysis of Haze Pollution: Method Development and Results from Beijing, China.

    Science.gov (United States)

    Zheng, Guangjie; Duan, Fengkui; Ma, Yongliang; Zhang, Qiang; Huang, Tao; Kimoto, Takashi; Cheng, Yafang; Su, Hang; He, Kebin

    2016-05-01

    Haze episodes occurred in Beijing repeatedly in 2013, resulting in 189 polluted days. These episodes differed in terms of sources, formation processes, and chemical composition and thus required different control policies. Therefore, an overview of the similarities and differences among these episodes is needed. For this purpose, we conducted one-year online observations and developed a program that can simultaneously divide haze episodes and identify their shapes. A total of 73 episodes were identified, and their shapes were linked with synoptic conditions. Pure-haze events dominated in wintertime, whereas mixed haze-dust (PM2.5/PM10 haze-fog (Aerosol Water/PM2.5 ∼ 0.3) events dominated in spring and summer-autumn, respectively. For all types, increase of ratio of PM2.5 in PM10 was typically achieved before PM2.5 reached ∼150 μg/m(3). In all PM2.5 species observed, organic matter (OM) was always the most abundant component (18-60%), but it was rarely the driving factor: its relative contribution usually decreased as the pollution level increased. The only OM-driven episode observed was associated with intensive biomass-burning activities. In comparison, haze evolution generally coincided with increasing sulfur and nitrogen oxidation ratios (SOR and NOR), indicating the enhanced production of secondary inorganic species. Applicability of these conclusions required further tests with simultaneously multisite observations.

  12. Evolution of dislocation patterns and its application in prediction of flow stress

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhimin; SUN Yanrui

    2004-01-01

    The feature of dislocation patterns generated in plastic deformation is the ordered structure of alternative appearance of high and low dislocation density zones. With regard to the system of edge and screw dislocations, a nonlinear partial differential equation (eq. (13) in the text)including high order terms is established based on the reaction-diffusion equation. The contribution of cross slip of screw dislocations to the edge dislocation density is also considered in the analysis. The established equation has the typical feature of nonlinear system. Therefore, one does not need to deal with the complex expressions of the reaction and generation terms for dislocations. By theoretical analysis, the distance between adjacent high dislocation density zones (cell size or distance between cell walls) is obtained. By using this relationship, the flow stresses of ultrafine grained (UFG)copper and aluminum are predicted. The calculated results are well consistent with the experimental.

  13. Angiosperm n-alkane distribution patterns and the geologic record of C4 grassland evolution

    Science.gov (United States)

    Henderson, A.; Graham, H. V.; Patzkowsky, M.; Fox, D. L.; Freeman, K. H.

    2012-12-01

    n-Alkane average chain-length (ACL) patterns vary regionally with community composition and climate. To clarify the influence of phylogenetic and community patterns, we compiled and analyzed a global database of published n-alkane abundance for n-C27 to C35 homologs in modern plant specimens (n=205). ACL for waxes in C4 non-woody plants are longer than for woody plants, suggesting ACL can serve as an indicator of the three-dimensional structure of local vegetation. Further, these findings suggest compound-specific isotopic data for longer alkane homologs (C31, C33, C35) will proportionately represent non-woody vegetation and isotope measurements of C29 are more representative of woody vegetation. Thus, the combination of ACL and carbon isotope compositions should allow us to disentangle C3 woody, C3 non-woody, and C4 non-woody signals in terrestrial paleorecords. Application of this approach to the geologic record of Miocene C4 grassland expansion in the US Great Plains and the Siwaliks in Pakistan illustrate two very different transition scenarios. Alkane-specific isotopic data indicate C4 grasslands appeared 2.5 Ma in the Great Plains and 6.5 Ma in the Siwaliks, and ACL analysis indicates that this transition involved the replacement of woody vegetation in the US and the replacement of C3 grasses in Pakistan. Our analysis illustrates that, consistent with differences in the timing of C4 grassland, the drivers of change were likely not the same in these regions. Oxygen isotope records suggest that the more recent transition in the Great Plains was associated with climate cooling and possibly changes in disturbance regimes and that the transition in the Siwaliks was likely associated with warming and drying.

  14. 2-D geometrical analysis of deformation

    International Nuclear Information System (INIS)

    Engineering structures such as dams, bridges, high rise buildings, etc. are subject to deformation. Deformation survey is therefore necessary to determine the magnitude and direction of such movements for the purpose of safety assessment. In this study, a strategy for two-step analyses for deformation survey rising the two dimensional (2-D) geodetic method has been developed, consisting of independent least squares estimation (LSE) of each epoch followed by deformation detection. Important aspects on LSE include global and local testing. In deformation detection, the following aspects were implemented; datum definition by the user. determination of stable datum points, geometrical analysis of deformation and graphic presentation. The developed strategy has been implemented in three computer programs, COMPUT, DEFORM and STRANS. Tests carried out with simulated and known data show that the developed strategy and programs are applicable for 2-D geometrical detection of deformation. (Author)

  15. Robust and resistant 2D shape alignment

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Eiriksson, Hrafnkell

    2001-01-01

    We express the alignment of 2D shapes as the minimization of the norm of a linear vector function. The minimization is done in the \\$l\\_1\\$, \\$l\\_2\\$ and the \\$l\\_\\$\\backslash\\$infty\\$ norms using well known standard numerical methods. In particular, the \\$l\\_1\\$ and the \\$l\\_\\$\\backslash\\$infty\\......We express the alignment of 2D shapes as the minimization of the norm of a linear vector function. The minimization is done in the \\$l\\_1\\$, \\$l\\_2\\$ and the \\$l\\_\\$\\backslash\\$infty\\$ norms using well known standard numerical methods. In particular, the \\$l\\_1\\$ and the \\$l......\\_\\$\\backslash\\$infty\\$ norm alignments are formulated as linear programming problems. The linear vector function formulation along with the different norms results in alignment methods that are both resistant from influence from outliers, robust wrt. errors in the annotation and capable of handling missing datapoints...

  16. A new experimental approach for studying bacterial genomic island evolution identifies island genes with bacterial host-specific expression patterns

    Directory of Open Access Journals (Sweden)

    Nickerson Cheryl A

    2006-01-01

    Full Text Available Abstract Background Genomic islands are regions of bacterial genomes that have been acquired by horizontal transfer and often contain blocks of genes that function together for specific processes. Recently, it has become clear that the impact of genomic islands on the evolution of different bacterial species is significant and represents a major force in establishing bacterial genomic variation. However, the study of genomic island evolution has been mostly performed at the sequence level using computer software or hybridization analysis to compare different bacterial genomic sequences. We describe here a novel experimental approach to study the evolution of species-specific bacterial genomic islands that identifies island genes that have evolved in such a way that they are differentially-expressed depending on the bacterial host background into which they are transferred. Results We demonstrate this approach by using a "test" genomic island that we have cloned from the Salmonella typhimurium genome (island 4305 and transferred to a range of Gram negative bacterial hosts of differing evolutionary relationships to S. typhimurium. Systematic analysis of the expression of the island genes in the different hosts compared to proper controls allowed identification of genes with genera-specific expression patterns. The data from the analysis can be arranged in a matrix to give an expression "array" of the island genes in the different bacterial backgrounds. A conserved 19-bp DNA site was found upstream of at least two of the differentially-expressed island genes. To our knowledge, this is the first systematic analysis of horizontally-transferred genomic island gene expression in a broad range of Gram negative hosts. We also present evidence in this study that the IS200 element found in island 4305 in S. typhimurium strain LT2 was inserted after the island had already been acquired by the S. typhimurium lineage and that this element is likely not

  17. Non-linear Ice Sheet influence during deglaciation and its impact on the evolution of atmospheric teleconnection patterns

    Science.gov (United States)

    Dietrich, Stephan; Wassenburg, Jasper; Wei, Wei; Lohmann, Gerrit; Jens, Fohlmeister; Adrian, Immenhauser

    2013-04-01

    During present conditions atmospheric teleconnections such as the Arctic Oscillation/North Atlantic Oscillation (AO/NAO) have a major impact on Northern Hemispheric climate. However, the Early Holocene is characterized by the presence and melting of the Laurentide Ice Sheet (LIS) leading to a different background climate in comparison to today. Here we investigate the climate evolution during the early (9 ka BP, including LIS and melt water), mid (6 ka BP) and late Holocene (pre-industrial conditions) focussing on the mechanisms and feedbacks during deglaciation by applying the state-of-the-art earth system model COSMOS. A special interest is set on the evolution of atmospheric teleconnection patterns such as the AO/NAO and the Atlantic Multidecadal Oscillation (AMO) that have a major influence on North Atlantic/European climate. The evolution and relative importance of these oscillations throughout the Holocene, however, is still largely unknown. We demonstrate that North Atlantic/European climate is affected by a shift from a more ocean-ice-dominated climate during approx. 9 ka towards a more atmosphere-dominated one during the mid to late Holocene. To isolate the contributions of the presence of the LIS and the melt water we run four different model simulations for the early Holocene sensitivity study (a standard configuration only forced with green house gases and orbital parameters, one with the additional LIS topography, one with a melt water flux of 0.09 Sv, and a fourth that combines all the external forcings). The model results show that the influence of the LIS and its melt water contribution lead to a strong non-linear cooling of surface air temperatures during deglaciation. This synergetic influence of the Laurentide Ice Sheet strengthens the effect of melting on ocean circulation during the early Holocene. The severe colder background climate during deglaciation leads to a more vulnerable ocean circulation in terms of the Atlantic Meridional

  18. 2D-Tasks for Cognitive Rehabilitation

    OpenAIRE

    Caballero Hernandez, Ruth; Martinez Moreno, Jose Maria; García Molina, A.; Ferrer Celma, S.; Solana Sánchez, Javier; Sanchez Carrion, R.; Fernandez Casado, E.; Pérez Rodríguez, Rodrigo; Gomez Pulido, A.; Anglès Tafalla, C.; Cáceres Taladriz, César; Ferre Vergada, M.; Roig Rovira, Teresa; Garcia Lopez, P.; Tormos Muñoz, Josep M.

    2011-01-01

    Neuropsychological Rehabilitation is a complex clinic process which tries to restore or compensate cognitive and behavioral disorders in people suffering from a central nervous system injury. Information and Communication Technologies (ICTs) in Biomedical Engineering play an essential role in this field, allowing improvement and expansion of present rehabilitation programs. This paper presents a set of cognitive rehabilitation 2D-Tasks for patients with Acquired Brain Injury (ABI). These t...

  19. Realistic and efficient 2D crack simulation

    Science.gov (United States)

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  20. 2D materials: Graphene and others

    Science.gov (United States)

    Bansal, Suneev Anil; Singh, Amrinder Pal; Kumar, Suresh

    2016-05-01

    Present report reviews the recent advancements in new atomically thick 2D materials. Materials covered in this review are Graphene, Silicene, Germanene, Boron Nitride (BN) and Transition metal chalcogenides (TMC). These materials show extraordinary mechanical, electronic and optical properties which make them suitable candidates for future applications. Apart from unique properties, tune-ability of highly desirable properties of these materials is also an important area to be emphasized on.

  1. Engineering light outcoupling in 2D materials

    KAUST Repository

    Lien, Derhsien

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.

  2. Design of Spiking Central Pattern Generators for Multiple Locomotion Gaits in Hexapod Robots by Christiansen Grammar Evolution

    Directory of Open Access Journals (Sweden)

    Andrés Espinal

    2016-07-01

    Full Text Available This paper deals with the design of Spiking Central Pattern Generators (SCPGs to achieve locomotion at different frequencies in legged robots and their hardware implementation in a FPGA and validation on a real hexapod robot. Herein, the SCPGs are automatically designed by a Christiansen Grammar Evolution (CGE-based methodology. It is, the CGE performs a solution for the configurations (synaptic weights and connections of each neuron in the SCPG. This is carried out through the indirect representation of a candidate solution that evolves to replicate a specific spike train according to a locomotion pattern (gait by measuring the similarity between the spike train with the SPIKE-Distance to drive the search to a correct configuration. By using this evolutionary approach, several SCPG design specifications can be explicitly added into the fitness function to achieve the SPIKE-distance criteria, such as: looking for SNNs with minimal connectivity or a CPG able to generate different locomotion gaits only by changing the initial input stimuli. The SCPG designs have been successfully implemented on a Spartan 6 FPGA board and a real time validation on a 12 DOFs hexapod robot is presented.

  3. Adaptive evolution and environmental durability jointly structure phylodynamic patterns in avian influenza viruses.

    Directory of Open Access Journals (Sweden)

    Benjamin Roche

    2014-08-01

    Full Text Available Avian influenza viruses (AIVs have been pivotal to the origination of human pandemic strains. Despite their scientific and public health significance, however, there remains much to be understood about the ecology and evolution of AIVs in wild birds, where major pools of genetic diversity are generated and maintained. Here, we present comparative phylodynamic analyses of human and AIVs in North America, demonstrating (i significantly higher standing genetic diversity and (ii phylogenetic trees with a weaker signature of immune escape in AIVs than in human viruses. To explain these differences, we performed statistical analyses to quantify the relative contribution of several potential explanations. We found that HA genetic diversity in avian viruses is determined by a combination of factors, predominantly subtype-specific differences in host immune selective pressure and the ecology of transmission (in particular, the durability of subtypes in aquatic environments. Extending this analysis using a computational model demonstrated that virus durability may lead to long-term, indirect chains of transmission that, when coupled with a short host lifespan, can generate and maintain the observed high levels of genetic diversity. Further evidence in support of this novel finding was found by demonstrating an association between subtype-specific environmental durability and predicted phylogenetic signatures: genetic diversity, variation in phylogenetic tree branch lengths, and tree height. The conclusion that environmental transmission plays an important role in the evolutionary biology of avian influenza viruses-a manifestation of the "storage effect"-highlights the potentially unpredictable impact of wildlife reservoirs for future human pandemics and the need for improved understanding of the natural ecology of these viruses.

  4. Evolution of OTP-independent larval skeleton patterning in the direct-developing sea urchin, Heliocidaris erythrogramma.

    Science.gov (United States)

    Zhou, Na; Wilson, Keen A; Andrews, Mary E; Kauffman, Jeffery S; Raff, Rudolf A

    2003-12-15

    Heliocidaris erythrogramma is a direct-developing sea urchin that has evolved a modified ontogeny, a reduced larval skeleton, and accelerated development of the adult skeleton. The Orthopedia gene (Otp) encodes a homeodomain transcription factor crucial in patterning the larval skeleton of indirect-developing sea urchins. We compare the role of Otp in larvae of the indirect-developing sea urchin Heliocidaris tuberculata and its direct-developing congener H. erythrogramma. Otp is a single-copy gene with an identical protein sequence in these species. Expression of Otp is initiated by the late gastrula, initially in two cells of the oral ectoderm in H. tuberculata. These cells are restricted to oral ectoderm and exhibit left-right symmetry. There are about 266 copies of Otp mRNA per Otp- expressing cell in H. tuberculata. We tested OTP function in H. tuberculata and H. erythrogramma embryos by microinjection of Otp mRNA. Mis-expression of Otp mRNA in H. tuberculata radialized the embryos and caused defects during larval skeletogenesis. Mis-expression of Otp mRNA in H. erythrogramma embryos did not affect skeleton formation. This is consistent with the observation by in situ hybridization of no concentration of Otp transcript in any particular cells or region of the H. erythrogramma larva, and measurement of a level of less than one copy of endogenous Otp mRNA per cell in H. erythrogramma. OTP plays an important role in patterning the larval skeleton of H. tuberculata, but this role apparently has been lost in the evolution of the H. erythrogramma larva, and replaced by a new patterning mechanism.

  5. In silico evolution of gene cooption in pattern-forming gene networks.

    Science.gov (United States)

    Spirov, Alexander V; Sabirov, Marat A; Holloway, David M

    2012-01-01

    Gene recruitment or cooption occurs when a gene, which may be part of an existing gene regulatory network (GRN), comes under the control of a new regulatory system. Such re-arrangement of pre-existing networks is likely more common for increasing genomic complexity than the creation of new genes. Using evolutionary computations (EC), we investigate how cooption affects the evolvability, outgrowth and robustness of GRNs. We use a data-driven model of insect segmentation, for the fruit fly Drosophila, and evaluate fitness by robustness to maternal variability-a major constraint in biological development. We compare two mechanisms of gene cooption: a simpler one with gene Introduction and Withdrawal operators; and one in which GRN elements can be altered by transposon infection. Starting from a minimal 2-gene network, insufficient for fitting the Drosophila gene expression patterns, we find a general trend of coopting available genes into the GRN, in order to better fit the data. With the transposon mechanism, we find co-evolutionary oscillations between genes and their transposons. These oscillations may offer a new technique in EC for overcoming premature convergence. Finally, we comment on how a differential equations (in contrast to Boolean) approach is necessary for addressing realistic continuous variation in biochemical parameters. PMID:23365523

  6. In Silico Evolution of Gene Cooption in Pattern-Forming Gene Networks

    Directory of Open Access Journals (Sweden)

    Alexander V. Spirov

    2012-01-01

    Full Text Available Gene recruitment or cooption occurs when a gene, which may be part of an existing gene regulatory network (GRN, comes under the control of a new regulatory system. Such re-arrangement of pre-existing networks is likely more common for increasing genomic complexity than the creation of new genes. Using evolutionary computations (EC, we investigate how cooption affects the evolvability, outgrowth and robustness of GRNs. We use a data-driven model of insect segmentation, for the fruit fly Drosophila, and evaluate fitness by robustness to maternal variability—a major constraint in biological development. We compare two mechanisms of gene cooption: a simpler one with gene Introduction and Withdrawal operators; and one in which GRN elements can be altered by transposon infection. Starting from a minimal 2-gene network, insufficient for fitting the Drosophila gene expression patterns, we find a general trend of coopting available genes into the GRN, in order to better fit the data. With the transposon mechanism, we find co-evolutionary oscillations between genes and their transposons. These oscillations may offer a new technique in EC for overcoming premature convergence. Finally, we comment on how a differential equations (in contrast to Boolean approach is necessary for addressing realistic continuous variation in biochemical parameters.

  7. Patterns of evolution of myocyte damage after human heart transplantation detected by indium-111 monoclonal antimyosin

    International Nuclear Information System (INIS)

    The indium-111 labeled Fab fragment of antimyosin monoclonal antibody was used to study cardiac rejection and the time course of myocyte damage after transplantation. Fifty-three studies were performed in 21 patients, 17 men and 4 women, aged 19 to 54 years (mean 37 +/- 8), from 7 to 40 months after transplantation. Repeat studies were available in 8, and 10 were studied after the first year of transplantation. A heart-to-lung ratio was used for quantitation of uptake (normal 1.46 +/- 0.04). Differences between absent (1.69 +/- 0.29) and moderate (1.90 +/- 0.36) rejection were significant (p less than 0.03). Antimyosin ratio at 1 to 3 months (1.89 +/- 0.35) differed from that at greater than 12 months (1.65 +/- 0.2) (p less than 0.01). Repeat studies revealed a decrease in antimyosin ratio in 5 patients with uneventful clinical course; 2 had persistent activity after transplantation and suffered heart failure from rejection. After 1 year of transplantation uptake was within normal limits in 7 of 10 patients, and high uptake was associated with vascular rejection in 1. Because they can define evolving patterns of myocardial lesion activity, antimyosin studies could be useful both in patient management and in concentrating resources for those patients who most require them. The heart-to-lung ratio is suggested to monitor sequentially the degree of myocyte damage after transplantation

  8. 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.

  9. Fluctuation-induced patterns and rapid evolution in predator-prey ecosystems

    Science.gov (United States)

    Goldenfeld, Nigel

    2014-03-01

    Predator-prey ecosystems exhibit noisy, persistent cycles that cannot be described by intuitive population-level differential equations such as the Lotka-Volterra equations. Traditionally this paradox has been met by including additional nonlinearities such as predator satiation to force limit cycle behavior. Over the last few years, it has been realized that individual-level descriptions, combined with systematic perturbation techniques can reproduce the key features of such systems in a minimal way, without requiring many additional assumptions or fine tunings. Here I review work in this area that uses these techniques to treat spatial patterns and the phenomenon of rapidly evolving prey sub-populations. In the latter case, I show how stochastic individual-level models reproduce the key features observed in chemostats and in the wild, including anomalous phase shifts between predator and prey species, evolutionary cycles and cryptic cycles. This work shows that stochastic individual-level models naturally describe systems where evolutionary time scales surprisingly match ecosystem time scales.

  10. Long bone histology and growth patterns in ankylosaurs: implications for life history and evolution.

    Directory of Open Access Journals (Sweden)

    Martina Stein

    Full Text Available The ankylosaurs are one of the major dinosaur groups and are characterized by unique body armor. Previous studies on other dinosaur taxa have revealed growth patterns, life history and evolutionary mechanisms based on their long bone histology. However, to date nothing is known about long bone histology in the Ankylosauria. This study is the first description of ankylosaurian long bone histology based on several limb elements, which were sampled from different individuals from the Ankylosauridae and Nodosauridae. The histology is compared to that of other dinosaur groups, including other Thyreophora and Sauropodomorpha. Ankylosaur long bone histology is characterized by a fibrolamellar bone architecture. The bone matrix type in ankylosaurs is closest to that of Stegosaurus. A distinctive mixture of woven and parallel-fibered bone together with overall poor vascularization indicates slow growth rates compared to other dinosaurian taxa. Another peculiar characteristic of ankylosaur bone histology is the extensive remodeling in derived North American taxa. In contrast to other taxa, ankylosaurs substitute large amounts of their primary tissue early in ontogeny. This anomaly may be linked to the late ossification of the ankylosaurian body armor. Metabolically driven remodeling processes must have liberated calcium to ossify the protective osteodermal structures in juveniles to subadult stages, which led to further remodeling due to increased mechanical loading. Abundant structural fibers observed in the primary bone and even in remodeled bone may have improved the mechanical properties of the Haversian bone.

  11. The Influence of Facial Characteristics on the Relation between Male 2D:4D and Dominance.

    Directory of Open Access Journals (Sweden)

    Jan Ryckmans

    Full Text Available Although relations between 2D:4D and dominance rank in both baboons and rhesus macaques have been observed, evidence in humans is mixed. Whereas behavioral patterns in humans have been discovered that are consistent with these animal findings, the evidence for a relation between dominance and 2D:4D is weak or inconsistent. The present study provides experimental evidence that male 2D:4D is related to dominance after (fictitious male-male interaction when the other man has a dominant, but not a submissive or neutral face. This finding provides evidence that the relationship between 2D:4D and dominance emerges in particular, predictable situations and that merely dominant facial characteristics of another person are enough to activate supposed relationships between 2D:4D and dominance.

  12. Limit theorems for 2D invasion percolation

    CERN Document Server

    Damron, Michael

    2010-01-01

    We prove limit theorems and variance estimates for quantities related to ponds and outlets for 2D invasion percolation. We first exhibit several properties of a sequence (O(n)) of outlet variables, the n-th of which gives the number of outlets in the box centered at the origin of side length 2^n. The most important of these properties describe the sequence's renewal structure and exponentially fast mixing behavior. We use these to prove a central limit theorem and strong law of large numbers for (O(n)). We then show consequences of these limit theorems for the pond radii and outlet weights.

  13. Interparticle attraction in 2D complex plasmas

    CERN Document Server

    Kompaneets, Roman; Ivlev, Alexei V

    2015-01-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecular-like. In this Letter, we propose how to achieve a molecular-like interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  14. Periodically sheared 2D Yukawa systems

    Energy Technology Data Exchange (ETDEWEB)

    Kovács, Anikó Zsuzsa [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Hartmann, Peter [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Center for Astrophysics, Space Physics and Engineering Research (CASPER), One Bear Place 97310, Baylor University, Waco, Texas 76798 (United States); Donkó, Zoltán [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Physics Department, Boston College, Chestnut Hill, Massachusetts 20467 (United States)

    2015-10-15

    We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.

  15. Extrinsic curvature induced 2-d gravity

    CERN Document Server

    Viswanathan, K S

    1993-01-01

    Abtract: 2-dimensional fermions are coupled to extrinsic geometry of a conformally immersed surface in ${\\bf R}^3$ through gauge coupling. By integrating out the fermions, we obtain a WZNW action involving extrinsic curvature of the surface. Restricting the resulting effective action to surfaces of $h\\sqrt g=1$, an explicit form of the action invariant under Virasaro symmetry is obtained. This action is a sum of the geometric action for the Virasaro group and the light-cone action of 2-d gravity plus an interaction term. The central charges of the theory in both the left and right sectors are calculated.

  16. 2-d Simulations of Test Methods

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm

    2004-01-01

    using both a Newton and Bingham model for characterisation of the rheological properties of the concrete. From the results, it is expected that both the slump flow and L-box can be simulated quite accurately when the model is extended to 3-d and the concrete is characterised according to the Bingham...... approach is presented by showing initial results from 2-d simulations of the empirical test methods slump flow and L-box. This method assumes a homogeneous material, which is expected to correspond to particle suspensions e.g. concrete, when it remains stable. The simulations have been carried out when...... model....

  17. Instant HTMl5 2D platformer

    CERN Document Server

    Temple, Aidan

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. The step-by-step approach taken by this book will show you how to develop a 2D HTML5 platformer-based game that you will be able to publish to multiple devices.This book is great for anyone who has an interest in HTML5 games development, and who already has a basic to intermediate grasp on both the HTML markup and JavaScript programming languages. Therefore, due to this requirement, the book will not discuss the inner workings of either of these languages but will instead attempt to

  18. Phase Engineering of 2D Tin Sulfides.

    OpenAIRE

    Mutlu, Z; Wu, RJ; Wickramaratne, D.; Shahrezaei, S; Liu, C; Temiz, S; Patalano, A; M Ozkan; Lake, RK; Mkhoyan, KA; Ozkan, CS

    2016-01-01

    Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2...

  19. Interparticle Attraction in 2D Complex Plasmas

    Science.gov (United States)

    Kompaneets, Roman; Morfill, Gregor E.; Ivlev, Alexei V.

    2016-03-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecularlike. In this Letter, we propose how to achieve a molecularlike interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  20. Evolution of geographical place and niche space: Patterns of diversification in the North American sedge (Cyperaceae) flora.

    Science.gov (United States)

    Spalink, Daniel; Drew, Bryan T; Pace, Matthew C; Zaborsky, John G; Li, Pan; Cameron, Kenneth M; Givnish, Thomas J; Sytsma, Kenneth J

    2016-02-01

    The role of geography and ecology in speciation are often discussed in the context of phylogenetic niche conservatism (PNC), the propensity of lineages to retain ancestral niche related traits. However, a recent paradigm shift focuses instead on measuring divergence of these traits in conjunction with patterns of speciation. Under this framework, we analyzed the diversification of North America's third most diverse family, Cyperaceae ("sedges"), using a modified Parsimony Analysis of Endemicity approach to identify floristic regions and ordination statistics to quantify species distribution in a continuous manner. Utilizing over 200,000 georeferenced specimens, we characterized the geographical distribution and climatic and edaphic niche space occupied by each species. We constructed a supermatrix phylogeny of the North American sedge flora, aided in part by the sequencing of all sedges of Wisconsin, and employed a multifaceted approach to assess the role of geographical and ecological divergence on lineage diversification. In addition to measuring phylogenetic signal for these traits, we also measured pairwise phylogenetic distance of species within floristic regions, calculated rates of speciation, and tested for correlations of speciation rate to tempo of geographical and ecological evolution. Our analyses consistently show that evolutionarily related species tend to be geographically unrelated. Rates of geographical and ecological diversification are closely linked to tempo of speciation, and exploration of geographical place coincides with divergence in ecological niche space. We highlight the benefits of treating geography in a continuous manner, and stress the importance of employing a diverse suite of analytical approaches in testing hypotheses regarding the evolution of range and niche.

  1. Evolution of geographical place and niche space: Patterns of diversification in the North American sedge (Cyperaceae) flora.

    Science.gov (United States)

    Spalink, Daniel; Drew, Bryan T; Pace, Matthew C; Zaborsky, John G; Li, Pan; Cameron, Kenneth M; Givnish, Thomas J; Sytsma, Kenneth J

    2016-02-01

    The role of geography and ecology in speciation are often discussed in the context of phylogenetic niche conservatism (PNC), the propensity of lineages to retain ancestral niche related traits. However, a recent paradigm shift focuses instead on measuring divergence of these traits in conjunction with patterns of speciation. Under this framework, we analyzed the diversification of North America's third most diverse family, Cyperaceae ("sedges"), using a modified Parsimony Analysis of Endemicity approach to identify floristic regions and ordination statistics to quantify species distribution in a continuous manner. Utilizing over 200,000 georeferenced specimens, we characterized the geographical distribution and climatic and edaphic niche space occupied by each species. We constructed a supermatrix phylogeny of the North American sedge flora, aided in part by the sequencing of all sedges of Wisconsin, and employed a multifaceted approach to assess the role of geographical and ecological divergence on lineage diversification. In addition to measuring phylogenetic signal for these traits, we also measured pairwise phylogenetic distance of species within floristic regions, calculated rates of speciation, and tested for correlations of speciation rate to tempo of geographical and ecological evolution. Our analyses consistently show that evolutionarily related species tend to be geographically unrelated. Rates of geographical and ecological diversification are closely linked to tempo of speciation, and exploration of geographical place coincides with divergence in ecological niche space. We highlight the benefits of treating geography in a continuous manner, and stress the importance of employing a diverse suite of analytical approaches in testing hypotheses regarding the evolution of range and niche. PMID:26702956

  2. Human NKG2D-ligands: cell biology strategies to ensure immune recognition

    Directory of Open Access Journals (Sweden)

    Lola eFernández-Messina

    2012-09-01

    Full Text Available Immune recognition mediated by the activating receptor NKG2D plays an important role for the elimination of stressed cells, including tumours and virus-infected cells. On the other hand, the ligands for NKG2D can also be shed into the sera of cancer patients where they weaken the immune response by downmodulating the receptor on effector cells, mainly NK and T cells. Although both families of NKG2D-ligands, MICA/B and ULBPs, are related to MHC molecules and their expression is increased after stress, many differences are observed in terms of their biochemical properties and cell trafficking. In this paper, we summarise the variety of NKG2D-ligands and propose that selection pressure has driven evolution of diversity in their trafficking and shedding, but not receptor binding affinity. However, it is also possible to identify functional properties common to individual ULBP molecules and MICA/B alleles, but not generally conserved within the MIC or ULBP families. These characteristics likely represent examples of convergent evolution for efficient immune recognition, but are also attractive targets for pathogen immune evasion strategies. Categorization of NKG2D-ligands according to their biological features, rather than their genetic family, may help to achieve a better understanding of NKG2D-ligand association with disease.

  3. Optimal Control of 1D and 2D Circuit QED

    CERN Document Server

    Fisher, R; Glaser, S J; Marquardt, F; Schulte-Herbrueggen, T

    2009-01-01

    Optimal control can be used to significantly improve multi-qubit gates in quantum information processing hardware architectures based on superconducting circuit quantum electrodynamics. We apply this approach not only to dispersive gates of two qubits inside a cavity, but, more generally, to architectures based on two-dimensional arrays of cavities and qubits. For high-fidelity gate operations, simultaneous evolutions of controls and couplings in the two coupling dimensions of cavity grids are shown to be significantly faster than conventional sequential implementations. Even under experimentally realistic conditions speedups by a factor of three can be gained. The methods immediately scale to large grids and indirect gates between arbitrary pairs of qubits on the grid. They are anticipated to be paradigmatic for 2D arrays and lattices of controllable qubits.

  4. WFR-2D: an analytical model for PWAS-generated 2D ultrasonic guided wave propagation

    Science.gov (United States)

    Shen, Yanfeng; Giurgiutiu, Victor

    2014-03-01

    This paper presents WaveFormRevealer 2-D (WFR-2D), an analytical predictive tool for the simulation of 2-D ultrasonic guided wave propagation and interaction with damage. The design of structural health monitoring (SHM) systems and self-aware smart structures requires the exploration of a wide range of parameters to achieve best detection and quantification of certain types of damage. Such need for parameter exploration on sensor dimension, location, guided wave characteristics (mode type, frequency, wavelength, etc.) can be best satisfied with analytical models which are fast and efficient. The analytical model was constructed based on the exact 2-D Lamb wave solution using Bessel and Hankel functions. Damage effects were inserted in the model by considering the damage as a secondary wave source with complex-valued directivity scattering coefficients containing both amplitude and phase information from wave-damage interaction. The analytical procedure was coded with MATLAB, and a predictive simulation tool called WaveFormRevealer 2-D was developed. The wave-damage interaction coefficients (WDICs) were extracted from harmonic analysis of local finite element model (FEM) with artificial non-reflective boundaries (NRB). The WFR-2D analytical simulation results were compared and verified with full scale multiphysics finite element models and experiments with scanning laser vibrometer. First, Lamb wave propagation in a pristine aluminum plate was simulated with WFR-2D, compared with finite element results, and verified by experiments. Then, an inhomogeneity was machined into the plate to represent damage. Analytical modeling was carried out, and verified by finite element simulation and experiments. This paper finishes with conclusions and suggestions for future work.

  5. Comments on Thermalization in 2D CFT

    CERN Document Server

    de Boer, Jan

    2016-01-01

    We revisit certain aspects of thermalization in 2D CFT. In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a BTZ black hole. The extra conserved charges, while rendering $c < 1$ theories essentially integrable, therefore seem to have little effect o...

  6. Photocurrent spectroscopy of 2D materials

    Science.gov (United States)

    Cobden, David

    Confocal photocurrent measurements provide a powerful means of studying many aspects of the optoelectronic and electrical properties of a 2D device or material. At a diffraction-limited point they can provide a detailed absorption spectrum, and they can probe local symmetry, ultrafast relaxation rates and processes, electron-electron interaction strengths, and transport coefficients. We illustrate this with several examples, once being the photo-Nernst effect. In gapless 2D materials, such as graphene, in a perpendicular magnetic field a photocurrent antisymmetric in the field is generated near to the free edges, with opposite sign at opposite edges. Its origin is the transverse thermoelectric current associated with the laser-induced electron temperature gradient. This effect provides an unambiguous demonstration of the Shockley-Ramo nature of long-range photocurrent generation in gapless materials. It also provides a means of investigating quasiparticle properties. For example, in the case of graphene on hBN, it can be used to probe the Lifshitz transition that occurs due to the minibands formed by the Moire superlattice. We also observe and discuss photocurrent generated in other semimetallic (WTe2) and semiconducting (WSe2) monolayers. Work supported by DoE BES and NSF EFRI grants.

  7. Investigating embryonic expression patterns and evolution of AHI1 and CEP290 genes, implicated in Joubert syndrome.

    Directory of Open Access Journals (Sweden)

    Yu-Zhu Cheng

    Full Text Available Joubert syndrome and related diseases (JSRD are developmental cerebello-oculo-renal syndromes with phenotypes including cerebellar hypoplasia, retinal dystrophy and nephronophthisis (a cystic kidney disease. We have utilised the MRC-Wellcome Trust Human Developmental Biology Resource (HDBR, to perform in-situ hybridisation studies on embryonic tissues, revealing an early onset neuronal, retinal and renal expression pattern for AHI1. An almost identical pattern of expression is seen with CEP290 in human embryonic and fetal tissue. A novel finding is that both AHI1 and CEP290 demonstrate strong expression within the developing choroid plexus, a ciliated structure important for central nervous system development. To test if AHI1 and CEP290 may have co-evolved, we carried out a genomic survey of a large group of organisms across eukaryotic evolution. We found that, in animals, ahi1 and cep290 are almost always found together; however in other organisms either one may be found independent of the other. Finally, we tested in murine epithelial cells if Ahi1 was required for recruitment of Cep290 to the centrosome. We found no obvious differences in Cep290 localisation in the presence or absence of Ahi1, suggesting that, while Ahi1 and Cep290 may function together in the whole organism, they are not interdependent for localisation within a single cell. Taken together these data support a role for AHI1 and CEP290 in multiple organs throughout development and we suggest that this accounts for the wide phenotypic spectrum of AHI1 and CEP290 mutations in man.

  8. Buckling in quasi-2D polymers

    NARCIS (Netherlands)

    Edmondson, S; Frieda, K; Comrie, JE; Onck, PR; Huck, WTS

    2006-01-01

    Buckle-driven delamination and subsequent collapse of strained thin polymer films upon triggered release from the substrate is exploited to fabricate striking, well-defined ridging patterns (see figure). An analysis of these patterns is presented, including the effects of film thickness and the exte

  9. DEPTH-AVERAGED 2-D CALCULATION OF FLOW AND SEDIMENT TRANSPORT IN CURVED CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Weiming WU; Sam S. Y. WANG

    2004-01-01

    The helical flow significantly affects the flow, sediment transport and morphological evolution in curved channels. A semi-empirical formula is proposed to determine the cross-stream distribution of the helical flow intensity in the developed regions of a channel bend. It is then used to evaluate the dispersion terms in the depth-averaged 2-D momentum equations and suspended-load transport equation as well as the bed-load transport angle, thus enhancing the depth-averaged 2-D model to account for the effect of helical flow. The tests in several experimental and field cases show that the enhanced depth-averaged 2-D model can much more reasonably predict the shifting of main flow from inner bank to outer bank, the erosion along outer bank and deposition along inner bank than the depth-averaged 2-D model without considering this effect.

  10. Structural shifts of aldehyde dehydrogenase enzymes were instrumental for the early evolution of retinoid-dependent axial patterning in metazoans.

    Science.gov (United States)

    Sobreira, Tiago J P; Marlétaz, Ferdinand; Simões-Costa, Marcos; Schechtman, Deborah; Pereira, Alexandre C; Brunet, Frédéric; Sweeney, Sarah; Pani, Ariel; Aronowicz, Jochanan; Lowe, Christopher J; Davidson, Bradley; Laudet, Vincent; Bronner, Marianne; de Oliveira, Paulo S L; Schubert, Michael; Xavier-Neto, José

    2011-01-01

    Aldehyde dehydrogenases (ALDHs) catabolize toxic aldehydes and process the vitamin A-derived retinaldehyde into retinoic acid (RA), a small diffusible molecule and a pivotal chordate morphogen. In this study, we combine phylogenetic, structural, genomic, and developmental gene expression analyses to examine the evolutionary origins of ALDH substrate preference. Structural modeling reveals that processing of small aldehydes, such as acetaldehyde, by ALDH2, versus large aldehydes, including retinaldehyde, by ALDH1A is associated with small versus large substrate entry channels (SECs), respectively. Moreover, we show that metazoan ALDH1s and ALDH2s are members of a single ALDH1/2 clade and that during evolution, eukaryote ALDH1/2s often switched between large and small SECs after gene duplication, transforming constricted channels into wide opened ones and vice versa. Ancestral sequence reconstructions suggest that during the evolutionary emergence of RA signaling, the ancestral, narrow-channeled metazoan ALDH1/2 gave rise to large ALDH1 channels capable of accommodating bulky aldehydes, such as retinaldehyde, supporting the view that retinoid-dependent signaling arose from ancestral cellular detoxification mechanisms. Our analyses also indicate that, on a more restricted evolutionary scale, ALDH1 duplicates from invertebrate chordates (amphioxus and ascidian tunicates) underwent switches to smaller and narrower SECs. When combined with alterations in gene expression, these switches led to neofunctionalization from ALDH1-like roles in embryonic patterning to systemic, ALDH2-like roles, suggesting functional shifts from signaling to detoxification. PMID:21169504

  11. Initial Images of the Synthetic Aperture Radiometer 2D-STAR

    Science.gov (United States)

    Initial results obtained using a new synthetic aperture radiometer, 2D-STAR, a dual polarized, L-band radiometer that employs aperture synthesis in two dimensions are presented and analyzed. This airborne instrument is the natural evolution of a previous design that employed employs aperture synthes...

  12. 2D Time-lapse Seismic Tomography Using An Active Time Constraint (ATC) Approach

    Science.gov (United States)

    We propose a 2D seismic time-lapse inversion approach to image the evolution of seismic velocities over time and space. The forward modeling is based on solving the eikonal equation using a second-order fast marching method. The wave-paths are represented by Fresnel volumes rathe...

  13. Mining of the Topic Evolution Pattern of Network News%网络新闻话题演化模式挖掘

    Institute of Scientific and Technical Information of China (English)

    赵旭剑; 张立; 李波; 张晖; 杨春明; 喻琼; 王耀彬

    2015-01-01

    针对特定主题的新闻话题演化模式挖掘对于话题动态演化研究具有重要的研究意义和应用价值,能帮助人们清晰地梳理话题事件的来龙去脉,直观地展现话题演化轨迹的逻辑结构。针对该需求,本文提出一种面向特定话题的网络新闻话题演化模式挖掘方法,拟从挖掘话题演化逻辑的角度出发,针对特定话题(矿难事件)进行话题演化一般规律的深入分析,对话题演变过程进行阶段化表示,建立话题演化模式。实验结果表明,本文构建的特定话题演化模式具有较强的语义表达能力,符合话题逻辑。%Patterns mining for topic evolution of topic-specific news is of great significance and value in the research on topic dynamic evolution. It can help people clearly sort out topics of the whole story and intuitively show the logical structure of the topic evolution track. According to the requirement, this paper proposes a pattern mining method for topic-specific news evolution. Firstly, this method takes the in-depth analysis to the general rules of the topic evolution for the specific topic from the logical point of view of the topic evolution discovery, and then studies the topic evolution stage representation to establish the topic evolution patterns. Experimental results show that the topic-specific evolution pattern constructed in this paper has strong semantic expression ability, and accords with the topic logic.

  14. Epigenetic regulation of developmental expression of Cyp2d genes in mouse liver

    Directory of Open Access Journals (Sweden)

    Ye Li

    2012-04-01

    Full Text Available CYP2D6 expression in liver is age-dependent. Because epigenetic mechanisms, such as DNA methylation and histone modifications, modulate age-related gene expression during development, and are highly conserved among species, the current study examined the epigenetic regulation of age-related expression of the Cyp2d genes in mouse liver. DNA methylation (DNAme, histone 3 lysine 4 dimethylation (H3K4me2, and histone 3 lysine 27 trimethylation (H3K27me3 was established by ChIP-on-chip tiling microarrays from mouse livers at prenatal, neonatal, and adult stages. Levels of DNAme, H3K4me2, and H3K27me3 were analyzed in a genomic region containing the Cyp2d clustering genes and their surrounding genes. Gradually increased expression levels of the Cyp2d9, Cyp2d10, Cyp2d22, and Cyp2d26 genes from prenatal, through neonatal, to adult are associated with gradually increased levels of H3K4me2 in the nucleosomes associated with these genes. Gene expression patterns during liver development in several Cyp2d surrounding genes, such as Srebf2, Sept3, Ndufa6, Tcf2, Nfam1, and Cyb5r3, could be also explained by changes of DNA methylation, H3K4me2, or H3K27me3 in those genes. In conclusion, the current study demonstrates that the changes of DNA methylation and histone modifications are associated with age-related expression patterns of the Cyp2d genes and their surrounding genes in liver cells during development.

  15. Locality constraints and 2D quasicrystals

    International Nuclear Information System (INIS)

    The plausible assumption that long-range interactions between atoms are negligible in a quasicrystal leaks to the study of tilings that obey constraints on the local configurations of tiles. The theory of such constraints (called matching rules) for 2D quasicrystal tilings is reviewed here. Different types of matching rules are defined and examples of tilings obeying them are given where known. The role of tile decoration is discussed and is shown to be significant in at least two cases (octagonal and dodecagonal duals of periodic 4-grids and 6-grids). A new result is introduced: a constructive procedure is described for generating weak matching rules for tilings with N-fold symmetry, for any N that is either a prime number or twice a prime number. The physics associated with weak matching rules, results on local growth rules, and the case of icosahedral symmetry are all briefly discussed. (author). 29 refs, 4 figs

  16. Alignment free characterization of 2D gratings

    CERN Document Server

    Madsen, Morten Hannibal; Hansen, Poul-Erik; Jørgensen, Jan Friis

    2015-01-01

    Fast characterization of 2-dimensional gratings is demonstrated using a Fourier lens optical system and a differential optimization algorithm. It is shown that both the grating specific parameters such as the basis vectors and the angle between them and the alignment of the sample, such as the rotation of the sample around the x-, y-, and z-axis, can be deduced from a single measurement. More specifically, the lattice vectors and the angle between them have been measured, while the corrections of the alignment parameters are used to improve the quality of the measurement, and hence reduce the measurement uncertainty. Alignment free characterization is demonstrated on both a 2D hexagonal grating with a period of 700 nm and a checkerboard grating with a pitch of 3000 nm. The method can also be used for both automatic alignment and in-line characterization of gratings.

  17. Area preserving diffeomorphisms and 2-d gravity

    CERN Document Server

    La, H S

    1995-01-01

    Area preserving diffeomorphisms of a 2-d compact Riemannian manifold with or without boundary are studied. We find two classes of decompositions of a Riemannian metric, namely, h- and g-decomposition, that help to formulate a gravitational theory which is area preserving diffeomorphism (SDiffM-) invariant but not necessarily diffeomorphism invariant. The general covariance of equations of motion of such a theory can be achieved by incorporating proper Weyl rescaling. The h-decomposition makes the conformal factor of a metric SDiffM-invariant and the rest of the metric invariant under conformal diffeomorphisms, whilst the g-decomposition makes the conformal factor a SDiffM scalar and the rest a SDiffM tensor. Using these, we reformulate Liouville gravity in SDiffM invariant way. In this context we also further clarify the dual formulation of Liouville gravity introduced by the author before, in which the affine spin connection is dual to the Liouville field.

  18. Graphene suspensions for 2D printing

    Science.gov (United States)

    Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.

    2016-04-01

    It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).

  19. Numerical Evaluation of 2D Ground States

    Science.gov (United States)

    Kolkovska, Natalia

    2016-02-01

    A ground state is defined as the positive radial solution of the multidimensional nonlinear problem \\varepsilon propto k_ bot 1 - ξ with the function f being either f(u) =a|u|p-1u or f(u) =a|u|pu+b|u|2pu. The numerical evaluation of ground states is based on the shooting method applied to an equivalent dynamical system. A combination of fourth order Runge-Kutta method and Hermite extrapolation formula is applied to solving the resulting initial value problem. The efficiency of this procedure is demonstrated in the 1D case, where the maximal difference between the exact and numerical solution is ≈ 10-11 for a discretization step 0:00025. As a major application, we evaluate numerically the critical energy constant. This constant is defined as a functional of the ground state and is used in the study of the 2D Boussinesq equations.

  20. Metrology for graphene and 2D materials

    Science.gov (United States)

    Pollard, Andrew J.

    2016-09-01

    The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the

  1. 2D Gridded Surface Data Value-Added Product

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Q [Lawrence Livermore National Laboratory; Xie, S [Lawrence Livermore National Laboratory

    2015-08-30

    This report describes the Atmospheric Radiation Measurement (ARM) Best Estimate (ARMBE) 2-dimensional (2D) gridded surface data (ARMBE2DGRID) value-added product. Spatial variability is critically important to many scientific studies, especially those that involve processes of great spatial variations at high temporal frequency (e.g., precipitation, clouds, radiation, etc.). High-density ARM sites deployed at the Southern Great Plains (SGP) allow us to observe the spatial patterns of variables of scientific interests. The upcoming megasite at SGP with its enhanced spatial density will facilitate the studies at even finer scales. Currently, however, data are reported only at individual site locations at different time resolutions for different datastreams. It is difficult for users to locate all the data they need and requires extra effort to synchronize the data. To address these problems, the ARMBE2DGRID value-added product merges key surface measurements at the ARM SGP sites and interpolates the data to a regular 2D grid to facilitate the data application.

  2. Local currents in a 2D topological insulator.

    Science.gov (United States)

    Dang, Xiaoqian; Burton, J D; Tsymbal, Evgeny Y

    2015-12-23

    Symmetry protected edge states in 2D topological insulators are interesting both from the fundamental point of view as well as from the point of view of potential applications in nanoelectronics as perfectly conducting 1D channels and functional elements of circuits. Here using a simple tight-binding model and the Landauer-Büttiker formalism we explore local current distributions in a 2D topological insulator focusing on effects of non-magnetic impurities and vacancies as well as finite size effects. For an isolated edge state, we show that the local conductance decays into the bulk in an oscillatory fashion as explained by the complex band structure of the bulk topological insulator. We demonstrate that although the net conductance of the edge state is topologically protected, impurity scattering leads to intricate local current patterns. In the case of vacancies we observe vortex currents of certain chirality, originating from the scattering of current-carrying electrons into states localized at the edges of hollow regions. For finite size strips of a topological insulator we predict the formation of an oscillatory band gap in the spectrum of the edge states, the emergence of Friedel oscillations caused by an open channel for backscattering from an impurity and antiresonances in conductance when the Fermi energy matches the energy of the localized state created by an impurity. PMID:26610145

  3. A Comprehensive Analysis of Fermi Gamma-ray Burst Data: II. $E_{\\rm p}$-Evolution Patterns and Implications for the Observed Spectrum-Luminosity Relations

    CERN Document Server

    Lu, Rui-Jing; Liang, En-Wei; Zhang, Bin-Bin; Lü, Hou-Jun; Lian-Zhong,; Lü,; Lei, Wei-Hua; Zhang, Bing

    2012-01-01

    We present a time-resolved spectral analysis of 51 long and 11 short bright GRBs observed with the {\\em Femri}/GBM, paying special attention to $E_{\\rm p}$ evolution within a same burst. Among 8 single-pulse long GRBs, 5 show hard-to-soft evolution, while 3 show intensity-tracking. The multi-pulse long GRBs have more complicated patterns. Among the GRBs whose time-resolved spectrum is available for the first pulse, almost half (15/32 GRBs) show clear hard-to-soft evolution, and the other half (17/32 GRBs) show clear intensity-tracking. Later pulses typically show the tracking behavior, although a hard-to-soft evolution pattern was identified in the 2nd pulse of 2 GRBs whose pulses are well separated. Statistically, the hard-to-soft evolution pulses tend to be more asymmetric than the intensity-tracking ones, with a steeper rising wing than the falling wing. Short GRBs have $E_{\\rm p}$ tracking intensity exclusively with the 16ms time resolution analysis. We performed a simulation analysis, and suggest that at...

  4. Patterns of sequence divergence and evolution of the S orthologous regions between Asian and African cultivated rice species.

    Science.gov (United States)

    Guyot, Romain; Garavito, Andrea; Gavory, Frédérick; Samain, Sylvie; Tohme, Joe; Ghesquière, Alain; Lorieux, Mathias

    2011-01-01

    A strong postzygotic reproductive barrier separates the recently diverged Asian and African cultivated rice species, Oryza sativa and O. glaberrima. Recently a model of genetic incompatibilities between three adjacent loci: S(1)A, S(1) and S(1)B (called together the S(1) regions) interacting epistatically, was postulated to cause the allelic elimination of female gametes in interspecific hybrids. Two candidate factors for the S(1) locus (including a putative F-box gene) were proposed, but candidates for S(1)A and S(1)B remained undetermined. Here, to better understand the basis of the evolution of regions involved in reproductive isolation, we studied the genic and structural changes accumulated in the S(1) regions between orthologous sequences. First, we established an 813 kb genomic sequence in O. glaberrima, covering completely the S(1)A, S(1) and the majority of the S(1)B regions, and compared it with the orthologous regions of O. sativa. An overall strong structural conservation was observed, with the exception of three isolated regions of disturbed collinearity: (1) a local invasion of transposable elements around a putative F-box gene within S(1), (2) the multiple duplication and subsequent divergence of the same F-box gene within S(1)A, (3) an interspecific chromosomal inversion in S(1)B, which restricts recombination in our O. sativa×O. glaberrima crosses. Beside these few structural variations, a uniform conservative pattern of coding sequence divergence was found all along the S(1) regions. Hence, the S(1) regions have undergone no drastic variation in their recent divergence and evolution between O. sativa and O. glaberrima, suggesting that a small accumulation of genic changes, following a Bateson-Dobzhansky-Muller (BDM) model, might be involved in the establishment of the sterility barrier. In this context, genetic incompatibilities involving the duplicated F-box genes as putative candidates, and a possible strengthening step involving the

  5. Patterns of Sequence Divergence and Evolution of the S1 Orthologous Regions between Asian and African Cultivated Rice Species

    Science.gov (United States)

    Gavory, Frédérick; Samain, Sylvie; Tohme, Joe; Ghesquière, Alain; Lorieux, Mathias

    2011-01-01

    A strong postzygotic reproductive barrier separates the recently diverged Asian and African cultivated rice species, Oryza sativa and O. glaberrima. Recently a model of genetic incompatibilities between three adjacent loci: S1A, S1 and S1B (called together the S1 regions) interacting epistatically, was postulated to cause the allelic elimination of female gametes in interspecific hybrids. Two candidate factors for the S1 locus (including a putative F-box gene) were proposed, but candidates for S1A and S1B remained undetermined. Here, to better understand the basis of the evolution of regions involved in reproductive isolation, we studied the genic and structural changes accumulated in the S1 regions between orthologous sequences. First, we established an 813 kb genomic sequence in O. glaberrima, covering completely the S1A, S1 and the majority of the S1B regions, and compared it with the orthologous regions of O. sativa. An overall strong structural conservation was observed, with the exception of three isolated regions of disturbed collinearity: (1) a local invasion of transposable elements around a putative F-box gene within S1, (2) the multiple duplication and subsequent divergence of the same F-box gene within S1A, (3) an interspecific chromosomal inversion in S1B, which restricts recombination in our O. sativa×O. glaberrima crosses. Beside these few structural variations, a uniform conservative pattern of coding sequence divergence was found all along the S1 regions. Hence, the S1 regions have undergone no drastic variation in their recent divergence and evolution between O. sativa and O. glaberrima, suggesting that a small accumulation of genic changes, following a Bateson-Dobzhansky-Muller (BDM) model, might be involved in the establishment of the sterility barrier. In this context, genetic incompatibilities involving the duplicated F-box genes as putative candidates, and a possible strengthening step involving the chromosomal inversion might participate to

  6. Patterns of sequence divergence and evolution of the S orthologous regions between Asian and African cultivated rice species.

    Directory of Open Access Journals (Sweden)

    Romain Guyot

    Full Text Available A strong postzygotic reproductive barrier separates the recently diverged Asian and African cultivated rice species, Oryza sativa and O. glaberrima. Recently a model of genetic incompatibilities between three adjacent loci: S(1A, S(1 and S(1B (called together the S(1 regions interacting epistatically, was postulated to cause the allelic elimination of female gametes in interspecific hybrids. Two candidate factors for the S(1 locus (including a putative F-box gene were proposed, but candidates for S(1A and S(1B remained undetermined. Here, to better understand the basis of the evolution of regions involved in reproductive isolation, we studied the genic and structural changes accumulated in the S(1 regions between orthologous sequences. First, we established an 813 kb genomic sequence in O. glaberrima, covering completely the S(1A, S(1 and the majority of the S(1B regions, and compared it with the orthologous regions of O. sativa. An overall strong structural conservation was observed, with the exception of three isolated regions of disturbed collinearity: (1 a local invasion of transposable elements around a putative F-box gene within S(1, (2 the multiple duplication and subsequent divergence of the same F-box gene within S(1A, (3 an interspecific chromosomal inversion in S(1B, which restricts recombination in our O. sativa×O. glaberrima crosses. Beside these few structural variations, a uniform conservative pattern of coding sequence divergence was found all along the S(1 regions. Hence, the S(1 regions have undergone no drastic variation in their recent divergence and evolution between O. sativa and O. glaberrima, suggesting that a small accumulation of genic changes, following a Bateson-Dobzhansky-Muller (BDM model, might be involved in the establishment of the sterility barrier. In this context, genetic incompatibilities involving the duplicated F-box genes as putative candidates, and a possible strengthening step involving the chromosomal

  7. HIV evolution in early infection: selection pressures, patterns of insertion and deletion, and the impact of apobec

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette [Los Alamos National Laboratory; Bhattacharya, Tanmoy [Los Alamos National Laboratory; Giorgi, Elena [Los Alamos National Laboratory; Gaschen, B [Los Alamos National Laboratory; Daniels, M [Los Alamos National Laboratory

    2009-01-01

    The pattern of viral diversification in newly infected individuals provides information about the host environment and immune responses typically experienced by the newly transmitted virus. For example, sites that tend to evolve rapidly across multiple early-infection patients could be involved in enabling escape from common early immune responses, represent adaptation for rapid growth in a newly infected host, or reversion from less fit forms of the virus that were selected for immune escape in previous hosts. Here we investigated the diversification of HIV -I env coding sequences in 81 very early B SUbtype infections previously shown to have resulted from transmission or expansion of single viruses (n=78) or two closely related viruses (n=3). In these cases the sequence of the infecting virus can be estimated accurately, enabling inference of both the direction of substitutions as well as distinction between insertion and deletion events. By integrating information across multiple acutely infected hosts, we find evidence of adaptive evolution of HIV-1 envand identified a subset of codon sites that diversified more rapidly than can be explained by a model of neutral evolution. Of 24 such rapidly diversifying sites, 14 were either (i) clustered and embedded in CTL epitopes that were verified experimentally or predicted based on the individual's HLA or (ii) in a nucleotide context indicative of APOBEC mediated G-to-A substitutions, despite having excluded heavily hypermutated sequences prior to the analysis. In several cases, a rapidly evolving site was both embedded in an APOBEC motif and in a CTL epitope, suggesting that APOBEC may facilitate early immune escape. Ten rapidly diversifying sites could not be explained by CTL escape or APOBEC hypermutation, including the most frequently mutated site, in the fusion peptide of gp4l. We also examined the distribution, extent, and sequence context of insertions and deletions and provide evidence that the length

  8. Cervical cancer cell lines expressing NKG2D-ligands are able to down-modulate the NKG2D receptor on NKL cells with functional implications

    Directory of Open Access Journals (Sweden)

    Jimenez-Perez Miriam I

    2012-02-01

    Full Text Available Abstract Background Cervical cancer represents the third most commonly diagnosed cancer and the fourth leading cause of cancer-related deaths in women worldwide. Natural killer (NK cells play an important role in the defense against viruses, intracellular bacteria and tumors. NKG2D, an activating receptor on NK cells, recognizes MHC class I chain-related molecules, such as MICA/B and members of the ULBP/RAET1 family. Tumor-derived soluble NKG2D-ligands have been shown to down-modulate the expression of NKG2D on NK cells. In addition to the down-modulation induced by soluble NKG2D-ligands, it has recently been described that persistent cell-cell contact can also down-modulate NKG2D expression. The goal of this study was to determine whether the NKG2D receptor is down-modulated by cell-cell contact with cervical cancer cells and whether this down-modulation might be associated with changes in NK cell activity. Results We demonstrate that NKG2D expressed on NKL cells is down-modulated by direct cell contact with cervical cancer cell lines HeLa, SiHa, and C33A, but not with non-tumorigenic keratinocytes (HaCaT. Moreover, this down-modulation had functional implications. We found expression of NKG2D-ligands in all cervical cancer cell lines, but the patterns of ligand distribution were different in each cell line. Cervical cancer cell lines co-cultured with NKL cells or fresh NK cells induced a marked diminution of NKG2D expression on NKL cells. Additionally, the cytotoxic activity of NKL cells against K562 targets was compromised after co-culture with HeLa and SiHa cells, while co-culture with C33A increased the cytotoxic activity of the NKL cells. Conclusions Our results suggest that differential expression of NKG2D-ligands in cervical cancer cell lines might be associated with the down-modulation of NKG2D, as well as with changes in the cytotoxic activity of NKL cells after cell-cell contact with the tumor cells.

  9. 2-D soft x-ray arrays in the EAST

    Science.gov (United States)

    Chen, Kaiyun; Xu, Liqing; Hu, Liqun; Duan, Yanmin; Li, Xueqin; Yuan, Yi; Mao, Songtao; Sheng, Xiuli; Zhao, Jinlong

    2016-06-01

    A high spatial and temporal resolution soft x-ray (SXR) imaging diagnostic has been installed in EAST for the study of magnetohydrodynamics activities and core high-Z impurity transport. Up to 122 lines of sight view the poloidal plasma from three directions (two up-down symmetrical horizontal arrays and one vertical array), which renders the diagnostic able to provide detailed tomographic reconstructions under various conditions. Fourier-Bessel method based on flux coordinates was employed for 2-D SXR tomographic reconstruction. Examples of several events measured by SXR diagnostic in EAST are shown, namely the crash patterns of sawtooth, periodical burst of edge localized modes, and the transport of high-Z intrinsic impurities.

  10. 2D Seismic Reflection Data across Central Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Valerie; Leetaru, Hannes

    2014-09-30

    In a continuing collaboration with the Midwest Geologic Sequestration Consortium (MGSC) on the Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins project, Schlumberger Carbon Services and WesternGeco acquired two-dimensional (2D) seismic data in the Illinois Basin. This work included the design, acquisition and processing of approximately 125 miles of (2D) seismic reflection surveys running west to east in the central Illinois Basin. Schlumberger Carbon Services and WesternGeco oversaw the management of the field operations (including a pre-shoot planning, mobilization, acquisition and de-mobilization of the field personnel and equipment), procurement of the necessary permits to conduct the survey, post-shoot closure, processing of the raw data, and provided expert consultation as needed in the interpretation of the delivered product. Three 2D seismic lines were acquired across central Illinois during November and December 2010 and January 2011. Traversing the Illinois Basin, this 2D seismic survey was designed to image the stratigraphy of the Cambro-Ordovician sections and also to discern the basement topography. Prior to this survey, there were no regionally extensive 2D seismic data spanning this section of the Illinois Basin. Between the NW side of Morgan County and northwestern border of Douglas County, these seismic lines ran through very rural portions of the state. Starting in Morgan County, Line 101 was the longest at 93 miles in length and ended NE of Decatur, Illinois. Line 501 ran W-E from the Illinois Basin – Decatur Project (IBDP) site to northwestern Douglas County and was 25 miles in length. Line 601 was the shortest and ran N-S past the IBDP site and connected lines 101 and 501. All three lines are correlated to well logs at the IBDP site. Originally processed in 2011, the 2D seismic profiles exhibited a degradation of signal quality below ~400 millisecond (ms) which made

  11. Face recognition method based on 2D-PCA and 2D-LDA%基于2D-PCA和2D-LDA的人脸识别方法

    Institute of Scientific and Technical Information of China (English)

    温福喜; 刘宏伟

    2007-01-01

    提出了基于2D-PCA、2D-LDA两种特征采用融合分类器的人脸识别方法.首先提取人脸图像的2D-PCA和2D-LDA特征,对不同特征在决策层对分类器进行融合.在ORL人脸库上的试验结果表明,分类器决策层融合方法在识别性能上优于2D-PCA和2D-LDA,更具有鲁棒性.

  12. Analysis list: Kmt2d [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Kmt2d Adipocyte,Pluripotent stem cell + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Kmt2d....1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Kmt2d.5.tsv http://dbarchiv...e.biosciencedbc.jp/kyushu-u/mm9/target/Kmt2d.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Kmt2d....Adipocyte.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Kmt2d.Pluripo

  13. Analysis list: KMT2D [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available KMT2D Blood,Digestive tract + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/KM...T2D.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/KMT2D.5.tsv http://dbarchive.biosc...iencedbc.jp/kyushu-u/hg19/target/KMT2D.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/KMT2D.Blo...od.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/KMT2D.Digestive_tract

  14. 2D manifold-independent spinfoam theory

    International Nuclear Information System (INIS)

    A number of background-independent quantization procedures have recently been employed in 4D nonperturbative quantum gravity. We investigate and illustrate these techniques and their relation in the context of a simple 2D topological theory. We discuss canonical quantization, loop or spin network states, path integral quantization over a discretization of the manifold, spin foam formulation and the fully background-independent definition of the theory using an auxiliary field theory on a group manifold. While several of these techniques have already been applied to this theory by Witten, the last one is novel: it allows us to give a precise meaning to the sum over topologies, and to compute background-independent and, in fact, 'manifold-independent' transition amplitudes. These transition amplitudes play the role of Wightman functions of the theory. They are physical observable quantities, and the canonical structure of the theory can be reconstructed from them via a C* algebraic GNS construction. We expect an analogous structure to be relevant in 4D quantum gravity

  15. Ion Transport in 2-D Graphene Nanochannels

    Science.gov (United States)

    Xie, Quan; Foo, Elbert; Duan, Chuanhua

    2015-11-01

    Graphene membranes have recently attracted wide attention due to its great potential in water desalination and selective molecular sieving. Further developments of these membranes, including enhancing their mass transport rate and/or molecular selectivity, rely on the understanding of fundamental transport mechanisms through graphene membranes, which has not been studied experimentally before due to fabrication and measurement difficulties. Herein we report the fabrication of the basic constituent of graphene membranes, i.e. 2-D single graphene nanochannels (GNCs) and the study of ion transport in these channels. A modified bonding technique was developed to form GNCs with well-defined geometry and uniform channel height. Ion transport in such GNCs was studied using DC conductance measurement. Our preliminary results showed that the ion transport in GNCs is still governed by surface charge at low concentrations (10-6M to 10-4M). However, GNCs exhibits much higher ionic conductances than silica nanochannels with the same geometries in the surface-charge-governed regime. This conductance enhancement can be attributed to the pre-accumulation of charges on graphene surfaces. The work is supported by the Faculty Startup Fund (Boston University, USA).

  16. Intermittency in 2D soap film turbulence

    CERN Document Server

    Cerbus, R T

    2013-01-01

    The Reynolds number dependency of intermittency for 2D turbulence is studied in a flowing soap film. The Reynolds number used here is the Taylor microscale Reynolds number R_{\\lambda}, which ranges from 20 to 800. Strong intermittency is found for both the inverse energy and direct enstrophy cascades as measured by (a) the pdf of velocity differences P(\\delta u(r)) at inertial scales r, (b) the kurtosis of P(\\partial_x u), and (c) the scaling of the so-called intermittency exponent \\mu, which is zero if intermittency is absent. Measures (b) and (c) are quantitative, while (a) is qualitative. These measurements are in disagreement with some previous results but not all. The velocity derivatives are nongaussian at all R_{\\lambda} but show signs of becoming gaussian as R_{\\lambda} increases beyond the largest values that could be reached. The kurtosis of P(\\delta u(r)) at various r indicates that the intermittency is scale dependent. The structure function scaling exponents also deviate strongly from the Kraichn...

  17. 2D DIGITAL SIMPLIFIED FLOW VALVE

    Institute of Scientific and Technical Information of China (English)

    Ruan Jian; Li Sheng; Pei Xiang; Burton R; Ukrainetz P; Bitner D

    2004-01-01

    The 2D digital simplified flow valve is composed of a pilot-operated valve designed with both rotary and linear motions of a single spool,and a stepper motor under continual control.How the structural parameters affect the static and dynamic characteristics of the valve is first clarified and a criterion for stability is presented.Experiments are designed to test the performance of the valve.It is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless,it is possible to maintain the dynamic response at a fairly high level,while keeping the leakage of the pilot stage at an acceptable level.One of the features of the digital valve is stage control.In stage control the nonlinearities,such as electromagnetic saturation and hysteresis,are greatly reduced.To a large extent the dynamic response of the valve is decided by the executing cycle of the control algorithm.

  18. Resolution Independent 2D Cartoon Video Conversion

    Directory of Open Access Journals (Sweden)

    MSF. Fayaza

    2016-03-01

    Full Text Available This paper describes a novel system for vectorizing 2D raster cartoon. The output videos are the resolution independent, smaller in file size. As a first step, input video is segment to scene thereafter all processes are done for each scene separately. Every scene contains foreground and background objects so in each and every scene foreground background classification is performed. Background details can occlude by foreground objects but when foreground objects move its previous position such occluded details exposed in one of the next frame so using that frame can fill the occluded area and can generate static background. Classified foreground objects are identified and the motion of the foreground objects tracked for this simple user assistance is required from those motion details of foreground object’s animation generated. Static background and foreground objects segmented using K-means clustering and each and every cluster’s vectorized using potrace. Using vectored background and foreground object animation path vector video regenerated.

  19. Identification of novel CYP2D7-2D6 hybrids: non-functional and functional variants

    Directory of Open Access Journals (Sweden)

    Andrea Gaedigk

    2010-10-01

    Full Text Available Polymorphic expression of CYP2D6 contributes to the wide range of activity observed for this clinically important drug metabolizing enzyme. In this report we describe novel CYP2D7/2D6 hybrid genes encoding non-functional and functional CYP2D6 protein and a CYP2D7 variant that mimics a CYP2D7/2D6 hybrid gene. Five kb long PCR products encompassing the novel genes were entirely sequenced. A quantitative assay probing in different gene regions was employed to determine CYP2D6 and 2D7 copy number variations and the relative position of the hybrid genes within the locus was assessed by long-range PCR. In addition to the previously known CYP2D6*13 and *66 hybrids, we describe three novel non-functional CYP2D7-2D6 hybrids with gene switching in exon 2 (CYP2D6*79, intron 2 (CYP2D6*80 and intron 5 (CYP2D6*67. A CYP2D7-specific T-ins in exon 1 causes a detrimental frame shift. One subject revealed a CYP2D7 conversion in the 5’-flanking region of a CYP2D6*35 allele, was otherwise unaffected (designated CYP2D6*35B. Finally, three DNAs revealed a CYP2D7 gene with a CYP2D6-like region downstream of exon 9 (designated CYP2D7[REP6]. Quantitative copy number determination, sequence analyses and long-range PCR mapping were in agreement and excluded the presence of additional gene units. Undetected hybrid genes may cause over-estimation of CYP2D6 activity (CYP2D6*1/*1 vs *1/hybrid, etc, but may also cause results that may interfere with the genotype determination. Detection of hybrid events, ‘single’ and tandem, will contribute to more accurate phenotype prediction from genotype data.

  20. Coalescence of Anderson-localized modes at an exceptional point in 2D random media

    CERN Document Server

    Bachelard, Nicolas; Arlandis, Julien; Touzani, Rachid; Sebbah, Patrick

    2014-01-01

    In non-hermitian systems, the particular position at which two eigenstates coalesce under a variation of a parameter in the complex plane is called an exceptional point. A non-perturbative theory is proposed which describes the evolution of modes in 2D open dielectric systems when permittivity distribution is modified. We successfully test this theory in a 2D disordered system to predict the position in the parameter space of the exceptional point between two Anderson-localized states. We observe that the accuracy of the prediction depends on the number of localized states accounted for. Such an exceptional point is experimentally accessible in practically relevant disordered photonic systems

  1. 2D to 3D transition of polymeric carbon nitride nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Chamorro-Posada, Pedro [Dpto. de Teoría de la Señal y Comunicaciones e IT, Universidad de Valladolid, ETSI Telecomunicación, Paseo Belén 15, 47011 Valladolid (Spain); Vázquez-Cabo, José [Dpto. de Teoría de la Señal y Comunicaciones, Universidad de Vigo, ETSI Telecomunicación, Lagoas Marcosende s/n, Vigo (Spain); Sánchez-Arévalo, Francisco M. [Instituto de Investigaciones en Materiales (IIM), Universidad Nacional Autónoma de México, Apdo. Postal 70–360, Cd. Universitaria, México D.F. 04510 (Mexico); Martín-Ramos, Pablo [Dpto. de Teoría de la Señal y Comunicaciones e IT, Universidad de Valladolid, ETSI Telecomunicación, Paseo Belén 15, 47011 Valladolid (Spain); Laboratorio de Materiales Avanzados (Advanced Materials Laboratory) ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, 34004 Palencia (Spain); Martín-Gil, Jesús; Navas-Gracia, Luis M. [Laboratorio de Materiales Avanzados (Advanced Materials Laboratory) ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, 34004 Palencia (Spain); Dante, Roberto C., E-mail: rcdante@yahoo.com [Laboratorio de Materiales Avanzados (Advanced Materials Laboratory) ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, 34004 Palencia (Spain)

    2014-11-15

    The transition from a prevalent turbostratic arrangement with low planar interactions (2D) to an array of polymeric carbon nitride nanosheets with stronger interplanar interactions (3D), occurring for samples treated above 650 °C, was detected by terahertz-time domain spectroscopy (THz-TDS). The simulated 3D material made of stacks of shifted quasi planar sheets composed of zigzagged polymer ribbons, delivered a XRD simulated pattern in relatively good agreement with the experimental one. The 2D to 3D transition was also supported by the simulation of THz-TDS spectra obtained from quantum chemistry calculations, in which the same broad bands around 2 THz and 1.5 THz were found for 2D and 3D arrays, respectively. This transition was also in accordance with the tightening of the interplanar distance probably due to an interplanar π bond contribution, as evidenced also by a broad absorption around 2.6 eV in the UV–vis spectrum, which appeared in the sample treated at 650 °C, and increased in the sample treated at 700 °C. The band gap was calculated for 1D and 2D cases. The value of 3.374 eV for the 2D case is, within the model accuracy and precision, in a relative good agreement with the value of 3.055 eV obtained from the experimental results. - Graphical abstract: 2D lattice mode vibrations and structural changes correlated with the so called “2D to 3D transition”. - Highlights: • A 2D to 3D transition has been detected for polymeric carbon nitride. • THz-TDS allowed us to discover and detect the 2D to 3D transition of polymeric carbon nitride. • We propose a structure for polymeric carbon nitride confirming it with THz-TDS.

  2. Finite state models of constrained 2d data

    DEFF Research Database (Denmark)

    Justesen, Jørn

    2004-01-01

    This paper considers a class of discrete finite alphabet 2D fields that can be characterized using tools front finite state machines and Markov chains. These fields have several properties that greatly simplify the analysis of 2D coding methods.......This paper considers a class of discrete finite alphabet 2D fields that can be characterized using tools front finite state machines and Markov chains. These fields have several properties that greatly simplify the analysis of 2D coding methods....

  3. Polynomial solution of 2D Kalman-Bucy filtering problem

    NARCIS (Netherlands)

    Sebek, M.

    1992-01-01

    The 2D version of the Kalman-Bucy filtering problem is formulated and then solved via 2D polynomial methods. The optimal filter is restricted to be a linear causal system. The design procedure is shown to consist of one 2D spectral factorization equation only. In fact, it works for n-D signals (n>2)

  4. Polynomial solution of 2D Kalman-Bucy filtering problem

    OpenAIRE

    Sebek, M.

    1992-01-01

    The 2D version of the Kalman-Bucy filtering problem is formulated and then solved via 2D polynomial methods. The optimal filter is restricted to be a linear causal system. The design procedure is shown to consist of one 2D spectral factorization equation only. In fact, it works for n-D signals (n>2) as well.

  5. FEM-2D, 2-D MultiGroup Diffusion in X-Y Geometry

    International Nuclear Information System (INIS)

    1 - Nature of physical problem solved: FEM-2D solves the two-dimensional diffusion equation in x-y geometry. This is done by the finite elements method. 2 - Method of solution: FEM-2D uses triangular elements with first and second order Lagrange approximations. The systems equations are formulated in multigroup form and solved by Cholesky procedure which operates only on nonzero elements. Various acceleration techniques are available for the outer iteration. Fluxes along various lines and rates in arbitrary zones may be output. 3 - Restrictions on the complexity of the problem: The code uses variable dimensioning. Thus, the problem size is restricted by the largest array which usually is the systems matrix. Fluxes of all groups are kept in memory. This might become another restrictive data set for a large number of groups. The validity of the results is restricted by the approximations used. FEM-2D requires a finite element net which allows the approximation of fluxes by at most parabolas. The node distribution should be more dense in areas of heavy flux changes (near absorbers or the reflector)

  6. 2D-DCT的FPGA实现%Implementation of 2D-DCT using FPGA

    Institute of Scientific and Technical Information of China (English)

    郭前岗; 潘磊; 周西峰

    2012-01-01

    This paper presents an implementation for 2D-DCT using FPGA. It replaces the adders and multipliers with distributed arithmetic which is based on lookup tables, This design reduces resources and improves the operation speed. The simulation results show that the datas transformed by 2D-DCT are consistent with expectations, which is significant for the digital image and video compression.%设计了采用FPGA来实现2D—DCT的方案,对于其中的关键部分——乘加运算,给出了基于查找表的分布式算法。整个设计节省了资源,提高了运算速度。仿真结果表明,经LC-2D-DCT变换后的数据与期望值总体上是一致的,这对于数字图像和视频压缩的研究有一定的意义。

  7. Similar patterns of rDNA evolution in synthetic and recently formed natural populations of Tragopogon (Asteraceae allotetraploids

    Directory of Open Access Journals (Sweden)

    Soltis Pamela S

    2010-09-01

    homeologous rRNA gene copies occurred in both synthetic and natural populations of Tragopogon allopolyploids. The extent of these rDNA changes was generally higher in natural populations than in the synthetic lines. We hypothesize that locus-specific and chromosomal changes in early generations of allopolyploids may influence patterns of rDNA evolution in later generations.

  8. Power loss analysis of n-PASHA cells validated by 2D simulations

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, G.J.M.; Gutjahr, A.; Burgers, A.R.; Saynova, D.S.; Cesar, I.; Romijn, I.G.

    2013-10-15

    To reach >21% efficiency for the n-Pasha (passivated all sides H-pattern) cell of ECN, reliable power-loss analyses are essential. A power-loss analysis is presented that is based on experimental data but validated and completed by 2D simulations. The analysis is used to identify the key factors that will contribute most to achieving >21% efficiency.

  9. Sparse Non-negative Matrix Factor 2-D Deconvolution for Automatic Transcription of Polyphonic Music

    DEFF Research Database (Denmark)

    Schmidt, Mikkel N.; Mørup, Morten

    2006-01-01

    We present a novel method for automatic transcription of polyphonic music based on a recently published algorithm for non-negative matrix factor 2-D deconvolution. The method works by simultaneously estimating a time-frequency model for an instrument and a pattern corresponding to the notes which...... are played based on a log-frequency spectrogram of the music....

  10. Correlated Electron Phenomena in 2D Materials

    Science.gov (United States)

    Lambert, Joseph G.

    In this thesis, I present experimental results on coherent electron phenomena in layered two-dimensional materials: single layer graphene and van der Waals coupled 2D TiSe2. Graphene is a two-dimensional single-atom thick sheet of carbon atoms first derived from bulk graphite by the mechanical exfoliation technique in 2004. Low-energy charge carriers in graphene behave like massless Dirac fermions, and their density can be easily tuned between electron-rich and hole-rich quasiparticles with electrostatic gating techniques. The sharp interfaces between regions of different carrier densities form barriers with selective transmission, making them behave as partially reflecting mirrors. When two of these interfaces are set at a separation distance within the phase coherence length of the carriers, they form an electronic version of a Fabry-Perot cavity. I present measurements and analysis of multiple Fabry-Perot modes in graphene with parallel electrodes spaced a few hundred nanometers apart. Transition metal dichalcogenide (TMD) TiSe2 is part of the family of materials that coined the term "materials beyond graphene". It contains van der Waals coupled trilayer stacks of Se-Ti-Se. Many TMD materials exhibit a host of interesting correlated electronic phases. In particular, TiSe2 exhibits chiral charge density waves (CDW) below TCDW ˜ 200 K. Upon doping with copper, the CDW state gets suppressed with Cu concentration, and CuxTiSe2 becomes superconducting with critical temperature of T c = 4.15 K. There is still much debate over the mechanisms governing the coexistence of the two correlated electronic phases---CDW and superconductivity. I will present some of the first conductance spectroscopy measurements of proximity coupled superconductor-CDW systems. Measurements reveal a proximity-induced critical current at the Nb-TiSe2 interfaces, suggesting pair correlations in the pure TiSe2. The results indicate that superconducting order is present concurrently with CDW in

  11. Stability Test for 2-D Continuous-Discrete Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Models of 2-D continuous-discrete systems are introduced, which can be used to describe some complex systems. Different from classical 2-D continuous systems or 2-D discrete systems, the asymptotic stability of the continuous-discrete systems is determined by Hurwitz-Schur stability (hybrid one) of 2-D characteristic polynomials of the systems. An algebraic algorithm with simpler test procedure for Hurwitz-Schur stability test of 2-D polynomials is developed. An example to illustrate the applications of the test approach is provided.

  12. Analysis list: Mef2d [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Mef2d Muscle + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Mef2d.1.ts...v http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Mef2d.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Mef2d....10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Mef2d.Muscle.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Muscle.gml ...

  13. CYP2D7 sequence variation interferes with TaqMan CYP2D6*15 and *35 genotyping

    Directory of Open Access Journals (Sweden)

    Amanda K Riffel

    2016-01-01

    Full Text Available TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35 which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696 SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe

  14. Latent heat induced rotation limited aggregation in 2D ice nanocrystals

    Science.gov (United States)

    Bampoulis, Pantelis; Siekman, Martin H.; Kooij, E. Stefan; Lohse, Detlef; Zandvliet, Harold J. W.; Poelsema, Bene

    2015-07-01

    The basic science responsible for the fascinating shapes of ice crystals and snowflakes is still not understood. Insufficient knowledge of the interaction potentials and the lack of relevant experimental access to the growth process are to blame for this failure. Here, we study the growth of fractal nanostructures in a two-dimensional (2D) system, intercalated between mica and graphene. Based on our scanning tunneling spectroscopy data, we provide compelling evidence that these fractals are 2D ice. They grow while they are in material contact with the atmosphere at 20 °C and without significant thermal contact to the ambient. The growth is studied in situ, in real time and space at the nanoscale. We find that the growing 2D ice nanocrystals assume a fractal shape, which is conventionally attributed to Diffusion Limited Aggregation (DLA). However, DLA requires a low mass density mother phase, in contrast to the actual currently present high mass density mother phase. Latent heat effects and consequent transport of heat and molecules are found to be key ingredients for understanding the evolution of the snow (ice) flakes. We conclude that not the local availability of water molecules (DLA), but rather them having the locally required orientation is the key factor for incorporation into the 2D ice nanocrystal. In combination with the transport of latent heat, we attribute the evolution of fractal 2D ice nanocrystals to local temperature dependent rotation limited aggregation. The ice growth occurs under extreme supersaturation, i.e., the conditions closely resemble the natural ones for the growth of complex 2D snow (ice) flakes and we consider our findings crucial for solving the "perennial" snow (ice) flake enigma.

  15. Functional characterization of a first avian cytochrome P450 of the CYP2D subfamily (CYP2D49.

    Directory of Open Access Journals (Sweden)

    Hua Cai

    Full Text Available The CYP2D family members are instrumental in the metabolism of 20-25% of commonly prescribed drugs. Although many CYP2D isoforms have been well characterized in other animal models, research concerning the chicken CYP2Ds is limited. In this study, a cDNA encoding a novel CYP2D enzyme (CYP2D49 was cloned from the chicken liver for the first time. The CYP2D49 cDNA contained an open reading frame of 502 amino acids that shared 52%-57% identities with other CYP2Ds. The gene structure and neighboring genes of CYP2D49 are conserved and similar to those of human CYP2D6. Additionally, similar to human CYP2D6, CYP2D49 is un-inducible in the liver and expressed predominantly in the liver, kidney and small intestine, with detectable levels in several other tissues. Metabolic assays of the CYP2D49 protein heterologously expressed in E. coli and Hela cells indicated that CYP2D49 metabolized the human CYP2D6 substrate, bufuralol, but not debrisoquine. Moreover, quinidine, a potent inhibitor of human CYP2D6, only inhibited the bufuralol 1'-hydroxylation activity of CYP2D49 to a negligible degree. All these results indicated that CYP2D49 had functional characteristics similar to those of human CYP2D6 but measurably differed in the debrisoquine 4'-hydroxylation and quinidine inhibitory profile. Further structure-function investigations that employed site-directed mutagenesis and circular dichroism spectroscopy identified the importance of Val-126, Glu-222, Asp-306, Phe-486 and Phe-488 in keeping the enzymatic activity of CYP2D49 toward bufuralol as well as the importance of Asp-306, Phe-486 and Phe-488 in maintaining the conformation of CYP2D49 protein. The current study is only the first step in characterizing the metabolic mechanism of CYP2D49; further studies are still required.

  16. Fabrication of 2D and 3D dendritic nanoarchitectures of CdS

    Institute of Scientific and Technical Information of China (English)

    GU Li

    2008-01-01

    The controlled preparation of two-dimensional (2D) and three-dimensional (3D) dendritic nanostructures of CdS was reported. 2D dendritic patterns are obtained through the self-assembly of nanoparticles under the entropy-driven force. 3D dendritic needle-like nanocrystals are prepared through an aqueous solution synthesis regulated by oleic acid molecules. Their growth mechanism is presumed to be the selective binding of OA molecules onto growing crystal planes. Techniques such as SEM, TEM, XRD, and FT-IR were employed to characterize the morphologies and structures of the obtained products.

  17. 2D wave-front shaping in optical superlattices using nonlinear volume holography.

    Science.gov (United States)

    Yang, Bo; Hong, Xu-Hao; Lu, Rong-Er; Yue, Yang-Yang; Zhang, Chao; Qin, Yi-Qiang; Zhu, Yong-Yuan

    2016-07-01

    Nonlinear volume holography is employed to realize arbitrary wave-front shaping during nonlinear processes with properly designed 2D optical superlattices. The concept of a nonlinear polarization wave in nonlinear volume holography is investigated. The holographic imaging of irregular patterns was performed using 2D LiTaO3 crystals with fundamental wave propagating along the spontaneous polarization direction, and the results agree well with the theoretical predictions. This Letter not only extends the application area of optical superlattices, but also offers an efficient method for wave-front shaping technology.

  18. The 2D Linearly Polarized Near-Field Focusing Based on Angularly Discretized Slot Arrays

    CERN Document Server

    Chen, Menglin; Ma, Zilong; Jiang, Lijun

    2014-01-01

    A 2-D near-field focusing design is proposed based on the circular slot array waveguide structures, synthesized using the array-factor theory, and demonstrated by full-wave simulations. The principle of beam-focusing is extended to the 2-D angularly discretized configuration using regular center-fed linear slots arranged in a circular pattern. By the mirror image arrangement of the slots, a linearly polarized focus in the near-field of the antenna, with negligible cross-polarization is achieved. Its beam-focusing properties are discussed in details and demonstrated by simulations.

  19. Climate and evolution: implications of some extinction patterns in African and European Machairodontine Cats of the Plio-Pleistocene

    Directory of Open Access Journals (Sweden)

    Antón, M.

    1998-12-01

    Full Text Available Estudios recientes sobre las correlaciones entre cambios climáticos globales y la evolución de la biota del Plio-Pleistoceno Africano han revelado aparentes discrepancias entre las fechas y la significación de eventos registrados en distintas fuentes. Las diferencias mas notables se refieren a un importante cambio en la proporción de isótopos de oxígeno marinas hace 2,5 millones de años, y a la posibilidad de una transición biótica relacionada causalmente con dicho cambio. Cambios en la vegetación detectados a través de los valores de isótopos estables en los paleosuelos sugieren que el principal cambio hacia una vegetación mas abierta ocurrió mas tarde, hace ∼1,7 millones de años. Nosotros estudiamos el problema refiriendonos en particular a los eventos de hace 1,7 millones de años, y a la extinción en Africa de los félidos con dientes de sable que se produce poco después, puesto que las extinciones de taxones euritópicos como estos probablemente señala cambios significativos en las condiciones ambientales. Nosotros comparamos el patrón de dichas extinciones con los de taxones semejantes 0 idénticos, en Eurasia y América, y sugerimos que en cada caso hay claros indicios de importantes cambios ambientales. Es probable que los cambios en la vegetación de Africa registrados hace ∼1,7 millones de años representen una respuesta en el medio terrestre alas cambios climáticos globales reflejados en el registro marino hace ∼1,9 millones de años.Recent discussions of correlations between global climatic change and evolution of the African Plio-Pleistocene biota have revealed apparent discrepancies between the timing and significance of events recorded in different data sets. The most notable differences have occurred in relation to a major shift in the ratio of marine oxygen isotopes by 2.5 myr and claims for a causally related transition in the biota. Vegetational changes recorded in palaeosol stable isotope

  20. Combining the switched-beam and beam-steering capabilities in a 2-D phased array antenna system

    Science.gov (United States)

    Tsai, Yi-Che; Chen, Yin-Bing; Hwang, Ruey-Bing

    2016-01-01

    This paper presents the development, fabrication, and measurement of a novel beam-forming system consisting of 16 subarray antennas, each containing four aperture-coupled patch antennas, and the application of this system in smart wireless communication systems. The beam patterns of each of the subarray antennas can be switched toward one of nine zones over a half space by adjusting the specific phase delay angles among the four antenna elements. Furthermore, when all subarrays are pointed at the same zone, slightly continuous beam steering in around 1° increments can be achieved by dynamically altering the progressive phase delay angle among the subarrays. Phase angle calibration was implemented by coupling each transmitter output and down converter into the in-phase/quadrature baseband to calculate the correction factor to the weight. In addition, to validate the proposed concepts and the fabricated 2-D phased array antenna system, this study measured the far-field radiation patterns of the aperture-coupled patch array integrated with feeding networks and a phase-calibration system to carefully verify its spatially switched-beam and beam-steering characteristics at a center frequency of 2.4 GHz which can cover the industrial, scientific, and medical band and some long-term evolution applications. In addition, measured results were compared with calculated results, and agreement between them was observed.

  1. Wavelet characterization of 2D turbulence and intermittency in magnetized electron plasmas

    Science.gov (United States)

    Romé, M.; Chen, S.; Maero, G.

    2016-06-01

    A study of the free relaxation of turbulence in a two-dimensional (2D) flow is presented, with a focus on the role of the initial vorticity conditions. Exploiting a well-known analogy with 2D inviscid incompressible fluids, the system investigated here is a magnetized pure electron plasma. The dynamics of this system are simulated by means of a 2D particle-in-cell code, starting from different spiral density (vorticity) distributions. A wavelet multiresolution analysis is adopted, which allows the coherent and incoherent parts of the flow to be separated. Comparison of the turbulent evolution in the different cases is based on the investigation of the time evolution of statistical properties, including the probability distribution functions and structure functions of the vorticity increments. It is also based on an analysis of the enstrophy evolution and its spectrum for the two components. In particular, while the statistical features assess the degree of flow intermittency, spectral analysis allows us not only to estimate the time required to reach a state of fully developed turbulence, but also estimate its dependence on the thickness of the initial spiral density distribution, accurately tracking the dynamics of both the coherent structures and the turbulent background. The results are compared with those relevant to annular initial vorticity distributions (Chen et al 2015 J. Plasma Phys. 81 495810511).

  2. Maximizing entropy of image models for 2-D constrained coding

    OpenAIRE

    Forchhammer, Søren; Danieli, Matteo; Burini, Nino; Zamarin, Marco; Ukhanova, Ann

    2010-01-01

    This paper considers estimating and maximizing the entropy of two-dimensional (2-D) fields with application to 2-D constrained coding. We consider Markov random fields (MRF), which have a non-causal description, and the special case of Pickard random fields (PRF). The PRF are 2-D causal finite context models, which define stationary probability distributions on finite rectangles and thus allow for calculation of the entropy. We consider two binary constraints and revisit the hard square const...

  3. Sparse Non-negative Matrix Factor 2-D Deconvolution

    DEFF Research Database (Denmark)

    Mørup, Morten; Schmidt, Mikkel N.

    2006-01-01

    We introduce the non-negative matrix factor 2-D deconvolution (NMF2D) model, which decomposes a matrix into a 2-dimensional convolution of two factor matrices. This model is an extension of the non-negative matrix factor deconvolution (NMFD) recently introduced by Smaragdis (2004). We derive...... and prove the convergence of two algorithms for NMF2D based on minimizing the squared error and the Kullback-Leibler divergence respectively. Next, we introduce a sparse non-negative matrix factor 2-D deconvolution model that gives easy interpretable decompositions and devise two algorithms for computing...

  4. Self-leveling 2D DPN probe arrays

    Science.gov (United States)

    Haaheim, Jason R.; Val, Vadim; Solheim, Ed; Bussan, John; Fragala, J.; Nelson, Mike

    2010-02-01

    Dip Pen Nanolithography® (DPN®) is a direct write scanning probe-based technique which operates under ambient conditions, making it suitable to deposit a wide range of biological and inorganic materials. Precision nanoscale deposition is a fundamental requirement to advance nanoscale technology in commercial applications, and tailoring chemical composition and surface structure on the sub-100 nm scale benefits researchers in areas ranging from cell adhesion to cell-signaling and biomimetic membranes. These capabilities naturally suggest a "Desktop Nanofab" concept - a turnkey system that allows a non-expert user to rapidly create high resolution, scalable nanostructures drawing upon well-characterized ink and substrate pairings. In turn, this system is fundamentally supported by a portfolio of MEMS devices tailored for microfluidic ink delivery, directed placement of nanoscale materials, and cm2 tip arrays for high-throughput nanofabrication. Massively parallel two-dimensional nanopatterning is now commercially available via NanoInk's 2D nano PrintArray™, making DPN a high-throughput (>3×107 μm2 per hour), flexible and versatile method for precision nanoscale pattern formation. However, cm2 arrays of nanoscopic tips introduce the nontrivial problem of getting them all evenly touching the surface to ensure homogeneous deposition; this requires extremely precise leveling of the array. Herein, we describe how we have made the process simple by way of a selfleveling gimbal attachment, coupled with semi-automated software leveling routines which bring the cm^2 chip to within 0.002 degrees of co-planarity. This excellent co-planarity yields highly homogeneous features across a square centimeter, with standard deviation. We have engineered the devices to be easy to use, wire-free, and fully integrated with both of our patterning tools: the DPN 5000, and the NLP 2000.

  5. Klassifikation von Standardebenen in der 2D-Echokardiographie mittels 2D-3D-Bildregistrierung

    Science.gov (United States)

    Bergmeir, Christoph; Subramanian, Navneeth

    Zum Zweck der Entwicklung eines Systems, das einen unerfahrenen Anwender von Ultraschall (US) zur Aufnahme relevanter anatomischer Strukturen leitet, untersuchen wir die Machbarkeit von 2D-US zu 3D-CT Registrierung. Wir verwenden US-Aufnahmen von Standardebenen des Herzens, welche zu einem 3D-CT-Modell registriert werden. Unser Algorithmus unterzieht sowohl die US-Bilder als auch den CT-Datensatz Vorverarbeitungsschritten, welche die Daten durch Segmentierung auf wesentliche Informationen in Form von Labein für Muskel und Blut reduzieren. Anschließend werden diese Label zur Registrierung mittels der Match-Cardinality-Metrik genutzt. Durch mehrmaliges Registrieren mit verschiedenen Initialisierungen ermitteln wir die im US-Bild sichtbare Standardebene. Wir evaluierten die Methode auf sieben US-Bildern von Standardebenen. Fünf davon wurden korrekt zugeordnet.

  6. Soccer players awarded one or more red cards exhibit lower 2D:4D ratios.

    Science.gov (United States)

    Mailhos, Alvaro; Buunk, Abraham P; Del Arca, Denise; Tutte, Verónica

    2016-09-01

    Anatomical, cognitive and behavioral sex differences are widely recognized in many species. It has been proposed that some of these differences might result from the organizing effects of prenatal sex steroids. In humans, males usually exhibit higher levels of physical aggression and prowess. In this study, we analyze the relationship between second-to-fourth digit (2D:4D) ratios-a proxy for prenatal androgen levels-and foul play and sporting performance in a sample of junior soccer players from a professional Uruguayan soccer club. Our results show that the most aggressive players (i.e., those awarded one or more red cards) have a more masculine finger pattern (lower 2D:4D ratio), while no relationship could be found between sporting performance and 2D:4D ratios. The results are discussed in the context of previous findings. Aggr. Behav. 42:417-426, 2016. © 2015 Wiley Periodicals, Inc. PMID:26699684

  7. Streamflow recession patterns can help unravel the role of climate and humans in landscape co-evolution

    Science.gov (United States)

    Bogaart, Patrick W.; van der Velde, Ype; Lyon, Steve W.; Dekker, Stefan C.

    2016-04-01

    Traditionally, long-term predictions of river discharges and their extremes include constant relationships between landscape properties and model parameters. However, due to the co-evolution of many landscape properties more sophisticated methods are necessary to quantify future landscape-hydrological model relationships. As a first step towards such an approach we use the Brutsaert and Nieber (1977) analysis method to characterize streamflow recession behaviour of ≈ 200 Swedish catchments within the context of global change and landscape co-evolution. Results suggest that the Brutsaert-Nieber parameters are strongly linked to the climate, soil, land use, and their interdependencies. Many catchments show a trend towards more non-linear behaviour, meaning not only faster initial recession but also slower recession towards base flow. This trend has been found to be independent from climate change. Instead, we suggest that land cover change, both natural (restoration of natural soil profiles in forested areas) and anthropogenic (reforestation and optimized water management), is probably responsible. Both change types are characterised by system adaptation and change, towards more optimal ecohydrological conditions, suggesting landscape co-evolution is at play. Given the observed magnitudes of recession changes during the past 50 years, predictions of future river discharge critically need to include the effects of landscape co-evolution. The interconnections between the controls of land cover and climate on river recession behaviour, as we have quantified in this paper, provide first-order handles to do so.

  8. 2D Four-Channel Perfect Reconstruction Filter Bank Realized with the 2D Lattice Filter Structure

    Directory of Open Access Journals (Sweden)

    Sezen S

    2006-01-01

    Full Text Available A novel orthogonal 2D lattice structure is incorporated into the design of a nonseparable 2D four-channel perfect reconstruction filter bank. The proposed filter bank is obtained by using the polyphase decomposition technique which requires the design of an orthogonal 2D lattice filter. Due to constraint of perfect reconstruction, each stage of this lattice filter bank is simply parameterized by two coefficients. The perfect reconstruction property is satisfied regardless of the actual values of these parameters and of the number of the lattice stages. It is also shown that a separable 2D four-channel perfect reconstruction lattice filter bank can be constructed from the 1D lattice filter and that this is a special case of the proposed 2D lattice filter bank under certain conditions. The perfect reconstruction property of the proposed 2D lattice filter approach is verified by computer simulations.

  9. Shared human-chimpanzee pattern of perinatal femoral shaft morphology and its implications for the evolution of hominin locomotor adaptations.

    Directory of Open Access Journals (Sweden)

    Naoki Morimoto

    Full Text Available BACKGROUND: Acquisition of bipedality is a hallmark of human evolution. How bipedality evolved from great ape-like locomotor behaviors, however, is still highly debated. This is mainly because it is difficult to infer locomotor function, and even more so locomotor kinematics, from fossil hominin long bones. Structure-function relationships are complex, as long bone morphology reflects phyletic history, developmental programs, and loading history during an individual's lifetime. Here we discriminate between these factors by investigating the morphology of long bones in fetal and neonate great apes and humans, before the onset of locomotion. METHODOLOGY/PRINCIPAL FINDINGS: Comparative morphometric analysis of the femoral diaphysis indicates that its morphology reflects phyletic relationships between hominoid taxa to a greater extent than taxon-specific locomotor adaptations. Diaphyseal morphology in humans and chimpanzees exhibits several shared-derived features, despite substantial differences in locomotor adaptations. Orangutan and gorilla morphologies are largely similar, and likely represent the primitive hominoid state. CONCLUSIONS/SIGNIFICANCE: These findings are compatible with two possible evolutionary scenarios. Diaphyseal morphology may reflect retained adaptive traits of ancestral taxa, hence human-chimpanzee shared-derived features may be indicative of the locomotor behavior of our last common ancestor. Alternatively, diaphyseal morphology might reflect evolution by genetic drift (neutral evolution rather than selection, and might thus be more informative about phyletic relationships between taxa than about locomotor adaptations. Both scenarios are consistent with the hypothesis that knuckle-walking in chimpanzees and gorillas resulted from convergent evolution, and that the evolution of human bipedality is unrelated to extant great ape locomotor specializations.

  10. A post-processing framework for localized 2D MR spectroscopy in vivo

    International Nuclear Information System (INIS)

    We propose a post-processing framework for localized two-dimensional (2D) magnetic resonance spectroscopy (MRS) in vivo. Our framework consists of corrections on eddy current and subject motion along with the framework used in conventional analytical 2D nuclear magnetic resonance (NMR) spectroscopy. In the eddy current correction, the phases of the free induction decays (FIDs) of the metabolite 1H are corrected along the t2 direction by the phase of the FID of water 1H. The corrected FIDs are Fourier transformed along the t2 direction, and interferograms of F(t1, ω2) are calculated. In the motion correction, the zero-order phase of the N-acetyl aspartate (NAA) singlet peak for each t1 axis is corrected after correction of frequency drift. We applied this framework in phantom and human brain measurements in a 4.7 T whole-body MR system. Two-dimensional data were collected by the localized 2D constant-time correlation spectroscopy (CT-COSY) sequence. We used a phantom containing a brain metabolite mixture of NAA, creatine (Cr), glutamate (Glu), glutamine (Gln) and γ-amino butyric acid (GABA). We demonstrated the eddy current correction procedure in the phantom experiments and the subject motion correction in human measurements. Though asymmetric patterns of the singlets of NAA and Cr were shown around the peak along the F2 direction in the reconstructed phantom spectra without eddy current correction, symmetric patterns arose after the correction. The t1 noise caused by those singlets was found in the human brain spectra without motion correction. The t1 noise was sufficiently suppressed by the motion correction. Our proposed post-processing framework for localized 2D MRS can improve the quality of in vivo 2D spectra and may allow improved quantitation and robustness of in vivo 2D spectroscopy. (author)

  11. An Incompressible 2D Didactic Model with Singularity and Explicit Solutions of the 2D Boussinesq Equations

    Science.gov (United States)

    Chae, Dongho; Constantin, Peter; Wu, Jiahong

    2014-09-01

    We give an example of a well posed, finite energy, 2D incompressible active scalar equation with the same scaling as the surface quasi-geostrophic equation and prove that it can produce finite time singularities. In spite of its simplicity, this seems to be the first such example. Further, we construct explicit solutions of the 2D Boussinesq equations whose gradients grow exponentially in time for all time. In addition, we introduce a variant of the 2D Boussinesq equations which is perhaps a more faithful companion of the 3D axisymmetric Euler equations than the usual 2D Boussinesq equations.

  12. Understanding the interaction between energetic ions and freestanding graphene towards practical 2D perforation

    Science.gov (United States)

    Buchheim, Jakob; Wyss, Roman M.; Shorubalko, Ivan; Park, Hyung Gyu

    2016-04-01

    We report experimentally and theoretically the behavior of freestanding graphene subjected to bombardment of energetic ions, investigating the capability of large-scale patterning of freestanding graphene with nanometer sized features by focused ion beam technology. A precise control over the He+ and Ga+ irradiation offered by focused ion beam techniques enables investigating the interaction of the energetic particles and graphene suspended with no support and allows determining sputter yields of the 2D lattice. We found a strong dependency of the 2D sputter yield on the species and kinetic energy of the incident ion beams. Freestanding graphene shows material semi-transparency to He+ at high energies (10-30 keV) allowing the passage of >97% He+ particles without creating destructive lattice vacancy. Large Ga+ ions (5-30 keV), in contrast, collide far more often with the graphene lattice to impart a significantly higher sputter yield of ~50%. Binary collision theory applied to monolayer and few-layer graphene can successfully elucidate this collision mechanism, in great agreement with experiments. Raman spectroscopy analysis corroborates the passage of a large fraction of He+ ions across graphene without much damaging the lattice whereas several colliding ions create single vacancy defects. Physical understanding of the interaction between energetic particles and suspended graphene can practically lead to reproducible and efficient pattern generation of unprecedentedly small features on 2D materials by design, manifested by our perforation of sub-5 nm pore arrays. This capability of nanometer-scale precision patterning of freestanding 2D lattices shows the practical applicability of focused ion beam technology to 2D material processing for device fabrication and integration.We report experimentally and theoretically the behavior of freestanding graphene subjected to bombardment of energetic ions, investigating the capability of large-scale patterning of

  13. PiCode: A New Picture-Embedding 2D Barcode.

    Science.gov (United States)

    Chen, Changsheng; Huang, Wenjian; Zhou, Baojian; Liu, Chenchen; Mow, Wai Ho

    2016-08-01

    Nowadays, 2D barcodes have been widely used as an interface to connect potential customers and advertisement contents. However, the appearance of a conventional 2D barcode pattern is often too obtrusive for integrating into an aesthetically designed advertisement. Besides, no human readable information is provided before the barcode is successfully decoded. This paper proposes a new picture-embedding 2D barcode, called PiCode, which mitigates these two limitations by equipping a scannable 2D barcode with a picturesque appearance. PiCode is designed with careful considerations on both the perceptual quality of the embedded image and the decoding robustness of the encoded message. Comparisons with the existing beautified 2D barcodes show that PiCode achieves one of the best perceptual qualities for the embedded image, and maintains a better tradeoff between image quality and decoding robustness in various application conditions. PiCode has been implemented in the MATLAB on a PC and some key building blocks have also been ported to Android and iOS platforms. Its practicality for real-world applications has been successfully demonstrated.

  14. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

    Directory of Open Access Journals (Sweden)

    Thomas Sturmberger

    2016-05-01

    Full Text Available We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK levels, and the patient was discharged on the third day after admission. Learning points: • Acute myocarditis can mimic acute coronary syndromes. • Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities. • 2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis.

  15. Symmetries and solvable models for evaporating 2D black holes

    OpenAIRE

    Cruz Muñoz, José Luis; Navarro-Salas, José; Navarro Navarro, Miguel; Talavera, C. F.

    1997-01-01

    We study the evaporation process of a 2D black hole in thermal equilibrium when the ingoing radiation is suddenly switched off. We also introduce global symmetries of generic 2D dilaton gravity models which generalize the extra symmetry of the CGHS model. © Elsevier Science B.V

  16. New Type of 2-D Laser Doppler Vibrometer

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The fundamentals and method of 2-D laser Doppler vibrometer are introduced.The factors influencing the measuring accuracy are analyzed. Moreover, the circuit for signal processing is designed. The vibrating amplitude and frequency of 2-D vibration in wider range can be measured simultaneously in non-contact means,the measuring results are accurate.

  17. Statische verweking talud: Handleiding Windows versie SLIQ2D

    NARCIS (Netherlands)

    Van den Ham, G.

    2009-01-01

    SLIQ2D is een quasi-2D computerprogramma waarmee het optreden voorspeld kan worden van een verwekingsvloeiing ofwel een instabiliteit van een onderwatertalud ten gevolge van verweking, gegeven de taludhelling, relatieve dichtheid en materiaaleigenschappen van het zand. Dit programma is in 1994 door

  18. Cascading Constrained 2-D Arrays using Periodic Merging Arrays

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Laursen, Torben Vaarby

    2003-01-01

    We consider a method for designing 2-D constrained codes by cascading finite width arrays using predefined finite width periodic merging arrays. This provides a constructive lower bound on the capacity of the 2-D constrained code. Examples include symmetric RLL and density constrained codes....... Numerical results for the capacities are presented....

  19. The relation between Euclidean and Lorentzian 2D quantum gravity

    NARCIS (Netherlands)

    Ambjørn, J.; Correia, J.; Kristjansen, C.; Loll, R.

    2006-01-01

    Starting from 2D Euclidean quantum gravity, we show that one recovers 2D Lorentzian quantum gravity by removing all baby universes. Using a peeling procedure to decompose the discrete, triangulated geometries along a one-dimensional path, we explicitly associate with each Euclidean space-time a (gen

  20. Van der Waals stacked 2D layered materials for optoelectronics

    Science.gov (United States)

    Zhang, Wenjing; Wang, Qixing; Chen, Yu; Wang, Zhuo; Wee, Andrew T. S.

    2016-06-01

    The band gaps of many atomically thin 2D layered materials such as graphene, black phosphorus, monolayer semiconducting transition metal dichalcogenides and hBN range from 0 to 6 eV. These isolated atomic planes can be reassembled into hybrid heterostructures made layer by layer in a precisely chosen sequence. Thus, the electronic properties of 2D materials can be engineered by van der Waals stacking, and the interlayer coupling can be tuned, which opens up avenues for creating new material systems with rich functionalities and novel physical properties. Early studies suggest that van der Waals stacked 2D materials work exceptionally well, dramatically enriching the optoelectronics applications of 2D materials. Here we review recent progress in van der Waals stacked 2D materials, and discuss their potential applications in optoelectronics.

  1. Microstructural properties and dislocation evolution on a GaN grown on patterned sapphire substrate: A transmission electron microscopy study

    Science.gov (United States)

    Kim, Y. H.; Ruh, H.; Noh, Y. K.; Kim, M. D.; Oh, J. E.

    2010-03-01

    The microstructural properties of a GaN layer grown on a patterned sapphire substrate (PSS) were studied in detail using transmission electron microscope techniques to determine dislocation and growth behaviors. Regular and uniform recrystallized GaN islands were observed on the protruding pattern. On a flat sapphire surface, the crystallographic orientation relationship of ⟨1¯21¯0⟩GaN on FS//⟨11¯00⟩sapphire and {11¯01}GaN on FS//{12¯13}sapphire existed between the GaN and the substrate. On the other hand, the orientation relationship of ⟨1¯21¯0⟩GaN layer//⟨1¯21¯0⟩GaN island on IS//⟨11¯00⟩sapphire and {11¯01}GaN layer//{0002}GaN island on IS//{12¯13}sapphire was confirmed among the GaN layer, the recrystallized GaN islands on an inclined sapphire surface and the PSS. The flat surface among the protruding patterns began to fill rapidly with GaN. Then, the GaN gradually overgrew the protruding pattern and coalesced near the summit as the growth time increased. The generation of threading dislocations was observed in the vicinity of the coalescence points near the top of the protruding patterns.

  2. Age, distance, and geochemical evolution within a monogenetic volcanic field: Analyzing patterns in the Auckland Volcanic Field eruption sequence

    Science.gov (United States)

    Corvec, Nicolas Le; Bebbington, Mark S.; Lindsay, Jan M.; McGee, Lucy E.

    2013-09-01

    The Auckland Volcanic Field (AVF) is a young active monogenetic basaltic field, which contains ˜50 volcanoes scattered across the Auckland metropolitan area. Understanding the temporal, spatial, and chemical evolution of the AVF during the last c.a. 250 ka is crucial in order to forecast a future eruption. Recent studies have provided new age constraints and potential temporal sequences of the past eruptions within the AVF. We use this information to study how the spatial distribution of the volcanic centers evolves with time, and how the chemical composition of the erupted magmas evolves with time and space. We seek to develop a methodology which compares successive eruptions to describe the link between geochemical and spatiotemporal evolution of volcanic centers within a monogenetic volcanic field. This methodology is tested with the present day data of the AVF. The Poisson nearest neighbor analysis shows that the spatial behavior of the field has been constant overtime, with the spatial distribution of the volcanic centers fitting the Poisson model within the significance levels. The results of the meta-analysis show the existence of correlations between the chemical composition of the erupted magmas and distance, volume, and time. The apparent randomness of the spatiotemporal evolution of the volcanic centers observed at the surface is probably influenced by the activity of the source. The methodology developed in this study can be used to identify possible relationships between composition trends and volume, time and/or distance to the behavior of the source, for successive eruptions of the AVF.

  3. Improved treatment of asthenosphere flow and melting in 2D numerical solutions for continental rifting: embedded vs nested modeling approaches.

    Science.gov (United States)

    de Monserrat, Albert; Morgan, Jason P.; Taramón, Jorge M.; Hall, Robert

    2016-04-01

    This work focuses on improving current 2D numerical approaches to modeling the boundary conditions associated with computing accurate deformation and melting associated with continental rifting. Recent models primarily use far-field boundary conditions that have been used for decades with little assessment of their effects on asthenospheric flow beneath the rifting region. All are extremely oversimplified. All are likely to significantly shape the pattern of asthenospheric flow beneath the stretching lithosphere which is associated with pressure-release melting and rift volcanism. The choice of boundary conditions may lead to different predictions of asthenospheric flow and melting associated with lithospheric stretching and breakup. We also find that they may affect the mode of crustal stretching. Here we discuss a suite of numerical experiments using a Lagrangian formulation, that compare these choices to likely more realistic boundary condition choices like the analytical solution for flow associated with two diverging plates stretching over a finite-width region. We also compare embedded and nested meshes with a high-resolution 2-D region within a cartesian 'whole mantle cross-section' box. Our initial results imply that the choice of far-field boundary conditions does indeed significantly influence predicted melting distributions and melt volumes associated with continental breakup. For calculations including asthenospheric melting, the 'finite width plate spreading' and embedded rifting boundary condition treatments lead to significantly smaller BC-influenced signals when using high-resolution calculation regions of order ~1000 km wide and 600 km deep within a lower resolution box of the order of >5000 km wide and 2800 km. We recommend their use when models are attempting to resolve the effects of asthenosphere flow and melting. We also discuss several examples of typical numerical 'artifacts' related to 'edge convection' at the sides of the stretching region

  4. Targeted fluorescence imaging enhanced by 2D materials: a comparison between 2D MoS2 and graphene oxide.

    Science.gov (United States)

    Xie, Donghao; Ji, Ding-Kun; Zhang, Yue; Cao, Jun; Zheng, Hu; Liu, Lin; Zang, Yi; Li, Jia; Chen, Guo-Rong; James, Tony D; He, Xiao-Peng

    2016-08-01

    Here we demonstrate that 2D MoS2 can enhance the receptor-targeting and imaging ability of a fluorophore-labelled ligand. The 2D MoS2 has an enhanced working concentration range when compared with graphene oxide, resulting in the improved imaging of both cell and tissue samples. PMID:27378648

  5. Sub-wavelength Lithography of Complex 2D and 3D Nanostructures without Dyes

    CERN Document Server

    Chaudhary, Raghvendra P; Ummethala, Govind; Hawal, Suyog R; Saxena, Sumit; Shukla, Shobha

    2016-01-01

    One-photon or two photon absorption by dye molecules in photopolymers enable direct 2D & 3D lithography of micro/nano structures with high spatial resolution and can be used effectively in fabricating artificially structured nanomaterials. However, the major bottleneck in unleashing the potential of this useful technique is the indispensable usage of dyes that are extremely expensive, highly toxic and usually insoluble in commercially available photopolymers. Here we report a simple, inexpensive and one-step technique for direct-writing of micro/nanostructures, with sub-wavelength resolution at extremely high speeds without using any one photon or two photon absorbing dye. We incorporated large amount (20 weight %) of inexpensive photoinitiator into the photopolymer and utilized its two-photon absorbing property for sub-wavelength patterning. Complex 2D and 3D patterns were fabricated with sub-micron resolution, in commercially available liquid photopolymer to show the impact/versatility of this technique...

  6. The evolution pattern of rDNA ITS in Avena and phylogenetic relationship of the Avena species (Poaceae: Aveneae).

    Science.gov (United States)

    Peng, Yuan-Ying; Baum, Bernard R; Ren, Chang-Zhong; Jiang, Qian-Tao; Chen, Guo-Yue; Zheng, You-Liang; Wei, Yu-Ming

    2010-10-01

    Ribosomal ITS sequences are commonly used for phylogenetic reconstruction because they are included in rDNA repeats, and these repeats often undergo rapid concerted evolution within and between arrays. Therefore, the rDNA ITS copies appear to be virtually identical and can sometimes be treated as a single gene. In this paper we examined ITS polymorphism within and among 13 diploid (A and C genomes), seven tetraploid (AB, AC and CC genomes) and four hexaploid (ACD genome) to infer the extent and direction of concerted evolution, and to reveal the phylogenetic and genome relationship among species of Avena. A total of 170 clones of the ITS1-5.8S-ITS2 fragment were sequenced to carry out haplotype and phylogenetic analysis. In addition, 111 Avena ITS sequences retrieved from GenBank were combined with 170 clones to construct a phylogeny and a network. We demonstrate the major divergence between the A and C genomes whereas the distinction among the A and B/D genomes was generally not possible. High affinity among the A(d) genome species A. damascena and the ACD genome species A. fatua was found, whereas the rest of the ACD genome hexaploids and the AACC tetraploids were highly affiliated with the A(l) genome diploid A. longiglumis. One of the AACC species A. murphyi showed the closest relationship with most of the hexaploid species. Both C(v) and C(p) genome species have been proposed as paternal donors of the C-genome carrying polyploids. Incomplete concerted evolution is responsible for the observed differences among different clones of a single Avena individual. The elimination of C-genome rRNA sequences and the resulting evolutionary inference of hexaploid species are discussed.

  7. Dissociation of expression patterns of homeodomain transcription factors in the evolution of developmental mode in the sea urchins Heliocidaris tuberculata and H. erythrogramma.

    Science.gov (United States)

    Wilson, Keen A; Andrews, Mary E; Raff, Rudolf A

    2005-01-01

    The direct-developing sea urchin species Heliocidaris erythrogramma has a radically modified ontogeny. Along with gains of novel features, its entire ectoderm has been reorganized, resulting in the apparent absence of a differentiated oral ectoderm, a major module present in the pluteus of indirect-developing species, such as H. tuberculata. The restoration of an obvious oral ectoderm in H. erythrogrammaxH. tuberculata hybrids, indicates the action of dominant regulatory factors from the H. tuberculata genome. We sought candidate regulatory genes based on the prediction that they should include genes that govern development of the oral ectoderm in the pluteus, but play different roles in H. erythrogramma. Such genes may have a large effect in the evolution of development. Goosecoid (Gsc), Msx, and the sea urchin Abd-B-like gene (Hox11/13b) are present and expressed in both species and the hybrid embryos. Both Gsc and Msx are oral ectoderm specific in H. tuberculata, and show novel and distinct expression patterns in H. erythrogramma. Gsc assumes a novel ectodermal pattern and Msx shifts to a novel and largely mesodermal pattern. Both Gsc and Msx show a restoration of oral ectoderm expression in hybrids. Hox11/13b is not expressed in oral ectoderm in H. tuberculata, but is conserved in posterior spatial expression among H. tuberculata, H. erythrogramma and hybrids, serving as a control. Competitive RT-PCR shows that Gsc, Msx, and Hox11/13b are under different quantitative and temporal controls in the Heliocidaris species and the hybrids. The implications for the involvement of these genes in the rapid evolution of a direct developing larva are discussed.

  8. Project Paleonao: How know the pattern of the rains. Spanish and Portuguese researchers reconstruct the climatic evolution of the North

    International Nuclear Information System (INIS)

    NAO, the effect of the North Atlantic oscillation, is the difference of air pressure between Iceland and the Azores, and that which governs climate variation every twelve months. To study and understand this phenomenon, which determines the arrival or not of the rains and influence on marine and terrestrial ecosystems are It launched the Paleonao Project. Based on historical weather records, its researchers use sensors natural lakes to collect data. is the case of the Penalara glacial lagoon, whose sediments they allow to know the evolution of the climate since thousands of years and to observe long-term trends of what will eventually passing in terms of precipitation and temperature changes. (Author)

  9. 2D and 3D Numerical Simulations of Flux Cancellation

    Science.gov (United States)

    Karpen, Judith T.; DeVore, C.; Antiochos, S. K.; Linton, M. G.

    2009-01-01

    Cancellation of magnetic flux in the solar photosphere and chromosphere has been linked observationally and theoretically to a broad range of solar activity, from filament channel formation to CME initiation. Because this phenomenon is typically measured at only a single layer in the atmosphere, in the radial (line of sight) component of the magnetic field, the actual processes behind this observational signature are ambiguous. It is clear that reconnection is involved in some way, but the location of the reconnection sites and associated connectivity changes remain uncertain in most cases. We are using numerical modeling to demystify flux cancellation, beginning with the simplest possible configuration: a subphotospheric Lundquist flux tube surrounded by a potential field, immersed in a gravitationally stratified atmosphere, spanning many orders of magnitude in plasma beta. In this system, cancellation is driven slowly by a 2-cell circulation pattern imposed in the convection zone, such that the tops of the cells are located around the beta=1 level (i.e., the photosphere) and the flows converge and form a downdraft at the polarity inversion line; note however that no flow is imposed along the neutral line. We will present the results of 2D and 3D MHD-AMR simulations of flux cancellation, in which the flux at the photosphere begins in either an unsheared or sheared state. In all cases, a low-lying flux rope is formed by reconnection at the polarity inversion line within a few thousand seconds. The flux rope remains stable and does not rise, however, in contrast to models which do not include the presence of significant mass loading.

  10. Distinctive expression patterns of Hedgehog pathway genes in the Ciona intestinalis larva: implications for a role of Hedgehog signaling in postembryonic development and chordate evolution.

    Science.gov (United States)

    Islam, A F M Tariqul; Moly, Pricila Khan; Miyamoto, Yuki; Kusakabe, Takehiro G

    2010-02-01

    Members of the Hedgehog (Hh) family are soluble ligands that orchestrate a wide spectrum of developmental processes ranging from left-right axis determination of the embryo to tissue patterning and organogenesis. Tunicates, including ascidians, are the closest relatives of vertebrates, and elucidation of Hh signaling in ascidians should provide an important clue towards better understanding the role of this pathway in development. In previous studies, expression patterns of genes encoding Hh and its downstream factor Gli have been examined up to the tailbud stage in the ascidian embryo, but their expression in the larva has not been reported. Here we show the spatial expression patterns of hedgehog (Ci-hh1, Ci-hh2), patched (Ci-ptc), smoothened (Ci-smo), and Gli (Ci-Gli) orthologs in larvae of the ascidian Ciona intestinalis. The expression patterns of Ci-hh2 and Ci-Gli dramatically change during the period between the late tailbud embryo and the swimming larva. At the larval stage, expression of Ci-Gli was found in a central part of the endoderm and in the visceral ganglion, while Ci-hh2 was expressed in two discrete endodermal regions, anteriorly and posteriorly adjacent to the cells expressing Gli. The expression patterns of these genes suggest that the Hh ligand controls postembryonic development of the endoderm and the central nervous system. Expression of a gene encoding Hh in the anterior and/or pharyngeal endoderm is probably an ancient chordate character; diversification of regulation and targets of the Hh signaling in this region may have played a major role in the evolution of chordate body structures.

  11. Introduction to game physics with Box2D

    CERN Document Server

    Parberry, Ian

    2013-01-01

    Written by a pioneer of game development in academia, Introduction to Game Physics with Box2D covers the theory and practice of 2D game physics in a relaxed and entertaining yet instructional style. It offers a cohesive treatment of the topics and code involved in programming the physics for 2D video games. Focusing on writing elementary game physics code, the first half of the book helps you grasp the challenges of programming game physics from scratch, without libraries or outside help. It examines the mathematical foundation of game physics and illustrates how it is applied in practice thro

  12. Maximizing entropy of image models for 2-D constrained coding

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Danieli, Matteo; Burini, Nino;

    2010-01-01

    This paper considers estimating and maximizing the entropy of two-dimensional (2-D) fields with application to 2-D constrained coding. We consider Markov random fields (MRF), which have a non-causal description, and the special case of Pickard random fields (PRF). The PRF are 2-D causal finite...... £ 2 squares contains all 0s or all 1s. The maximum values of the entropy for the constraints are estimated and binary PRF satisfying the constraint are characterized and optimized w.r.t. the entropy. The maximum binary PRF entropy is 0.839 bits/symbol for the no uniform squares constraint. The entropy...

  13. The NH$_2$D hyperfine structure revealed by astrophysical observations

    OpenAIRE

    Daniel, F.; Coudert, L. H.; Punanova, A.; Harju, J.; Faure, A.; Roueff, E.; Sipilä, O.; Caselli, P.; Güsten, R.; Pon, A.; Pineda, J E

    2016-01-01

    The 1$_{11}$-1$_{01}$ lines of ortho and para--NH$_2$D (o/p-NH$_2$D), respectively at 86 and 110 GHz, are commonly observed to provide constraints on the deuterium fractionation in the interstellar medium. In cold regions, the hyperfine structure due to the nitrogen ($^{14}$N) nucleus is resolved. To date, this splitting is the only one which is taken into account in the NH$_2$D column density estimates. We investigate how the inclusion of the hyperfine splitting caused by the deuterium (D) n...

  14. Kalman Filter for Generalized 2-D Roesser Models

    Institute of Scientific and Technical Information of China (English)

    SHENG Mei; ZOU Yun

    2007-01-01

    The design problem of the state filter for the generalized stochastic 2-D Roesser models, which appears when both the state and measurement are simultaneously subjected to the interference from white noise, is discussed. The wellknown Kalman filter design is extended to the generalized 2-D Roesser models. Based on the method of "scanning line by line", the filtering problem of generalized 2-D Roesser models with mode-energy reconstruction is solved. The formula of the optimal filtering, which minimizes the variance of the estimation error of the state vectors, is derived. The validity of the designed filter is verified by the calculation steps and the examples are introduced.

  15. Optimization and practical implementation of ultrafast 2D NMR experiments

    Directory of Open Access Journals (Sweden)

    Luiz H. K. Queiroz Júnior

    2013-01-01

    Full Text Available Ultrafast 2D NMR is a powerful methodology that allows recording of a 2D NMR spectrum in a fraction of second. However, due to the numerous non-conventional parameters involved in this methodology its implementation is no trivial task. Here, an optimized experimental protocol is carefully described to ensure efficient implementation of ultrafast NMR. The ultrafast spectra resulting from this implementation are presented based on the example of two widely used 2D NMR experiments, COSY and HSQC, obtained in 0.2 s and 41 s, respectively.

  16. Materials for Flexible, Stretchable Electronics: Graphene and 2D Materials

    Science.gov (United States)

    Kim, Sang Jin; Choi, Kyoungjun; Lee, Bora; Kim, Yuna; Hong, Byung Hee

    2015-07-01

    Recently, 2D materials have been intensively studied as emerging materials for future electronics, including flexible electronics, photonics, and electrochemical energy storage devices. Among representative 2D materials (such as graphene, boron nitride, and transition metal dichalcogenides) that exhibit extraordinary properties, graphene stands out in the flexible electronics field due to its combination of high electron mobility, high thermal conductivity, high specific surface area, high optical transparency, excellent mechanical flexibility, and environmental stability. This review covers the synthesis, transfer, and characterization methods of graphene and 2D materials and graphene's application to flexible devices as well as comparison with other competing materials.

  17. Optimization and practical implementation of ultrafast 2D NMR experiments

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz Junior, Luiz H. K., E-mail: professorkeng@gmail.com [Universidade Federal de Sao Carlos (UFSC), SP (Brazil). Departamento de Quimica; Universidade Federal de Goias (UFGO), Goiania, GO (Brazil). Inst. de Quimica; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSC), SP (Brazil). Departamento de Quimica; Giraudeau, Patrick [Universite de Nantes (France). CNRS, Chimie et Interdisciplinarite: Synthese, Analyse, Modelisation

    2013-09-01

    Ultrafast 2D NMR is a powerful methodology that allows recording of a 2D NMR spectrum in a fraction of second. However, due to the numerous non-conventional parameters involved in this methodology its implementation is no trivial task. Here, an optimized experimental protocol is carefully described to ensure efficient implementation of ultrafast NMR. The ultrafast spectra resulting from this implementation are presented based on the example of two widely used 2D NMR experiments, COSY and HSQC, obtained in 0.2 s and 41 s, respectively. (author)

  18. 2D electron cyclotron emission imaging at ASDEX Upgrade (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Classen, I. G. J. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Boom, J. E.; Vries, P. C. de [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Suttrop, W.; Schmid, E.; Garcia-Munoz, M.; Schneider, P. A. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); Tobias, B.; Domier, C. W.; Luhmann, N. C. Jr. [University of California at Davis, Davis, California 95616 (United States); Donne, A. J. H. [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Jaspers, R. J. E. [Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Park, H. K. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Munsat, T. [University of Colorado, Boulder, Colorado 80309 (United States)

    2010-10-15

    The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfven eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.

  19. Common Patterns in the Evolution between the Luminous Neutron Star Low-Mass X-ray Binary Subclasses

    CERN Document Server

    Fridriksson, Joel K; Remillard, Ronald A

    2015-01-01

    The X-ray transient XTE J1701-462 was the first source seen to evolve through all known subclasses of low-magnetic-field neutron star low-mass X-ray binaries (NS-LMXBs), as a result of large changes in its mass accretion rate. To investigate to what extent similar evolution is seen in other NS-LMXBs we have performed a detailed study of the color-color and hardness-intensity diagrams (CDs and HIDs) of Cyg X-2, Cir X-1, and GX 13+1 -- three luminous X-ray binaries, containing weakly magnetized neutron stars, known to exhibit strong secular changes in their CD/HID tracks. Using the full set of Rossi X-ray Timing Explorer Proportional Counter Array data collected for the sources over the 16-year duration of the mission, we show that Cyg X-2 and Cir X-1 display CD/HID evolution with close similarities to XTE J1701-462. Although GX 13+1 shows behavior that is in some ways unique, it also exhibits similarities to XTE J1701-462, and we conclude that its overall CD/HID properties strongly indicate that it should be c...

  20. The complete mitochondrial genome of the Chinese hook snout carp Opsariichthys bidens (Actinopterygii: Cypriniformes) and an alternative pattern of mitogenomic evolution in vertebrate

    DEFF Research Database (Denmark)

    Wang, Xuzhen; Wang, Jun; He, Shunping;

    2007-01-01

    The complete mitochondrial genome sequence of the Chinese hook snout carp, Opsariichthys bidens, was newly determined using the long and accurate polymerase chain reaction method. The 16,611-nucleotide mitogenome contains 13 protein-coding genes, two rRNA genes (12S, 16S), 22 tRNA genes, and a no......The complete mitochondrial genome sequence of the Chinese hook snout carp, Opsariichthys bidens, was newly determined using the long and accurate polymerase chain reaction method. The 16,611-nucleotide mitogenome contains 13 protein-coding genes, two rRNA genes (12S, 16S), 22 tRNA genes...... genome of O. bidens reveals an alternative pattern of vertebrate mitochondrial evolution. For the mitochondrial protein genes of O. bidens, the most frequently used codon generally ends with either A or C, with C preferred over A for most fourfold degenerate codon families; the relative synonymous codon...... usage of G-ending codons is greatly elevated in all categories. The codon usage pattern of O. bidens mitochondrial protein genes is remarkably different from the general pattern found previously in the relatively closely related zebrafish and most other vertebrate mitochondria. Nucleotide bias at third...

  1. 2D Active Antenna Array Design for FD-MIMO System and Antenna Virtualization Techniques

    Directory of Open Access Journals (Sweden)

    Ioannis Tzanidis

    2015-01-01

    Full Text Available Full dimension MIMO (FD-MIMO is one of the key technologies presently studied in the 3GPP for the next generation long-term evolution advanced (LTE-A systems. By incorporating FD-MIMO into LTE/LTE-A systems, it is expected that system throughput will be drastically improved beyond what is possible in conventional LTE systems. This paper presets details on the 2D active antenna array design for FD-MIMO systems supporting 32 antenna elements. The FD-MIMO system allows for dynamic and adaptive precoding to be performed jointly across all antennas thus achieving more directional transmissions in the azimuth and elevation domains simultaneously, to a larger number of users. Finally, we discuss 2D antenna array port virtualization techniques for creating beams with wide coverage, necessary for broadcasting signals to all users within a sector, such as the CRS (Common Reference Signal.

  2. Mechanical Modelling of Pultrusion Process: 2D and 3D Numerical Approaches

    DEFF Research Database (Denmark)

    Baran, Ismet; Hattel, Jesper Henri; Akkerman, Remko;

    2015-01-01

    , a mechanical analysis should be performed. In the present work, the two dimensional (2D) quasi-static plane strain mechanical model for the pultrusion of a thick square profile developed by the authors is further improved using generalized plane strain elements. In addition to that, a more advanced 3D thermo-chemical-mechanical......The process induced variations such as residual stresses and distortions are a critical issue in pultrusion, since they affect the structural behavior as well as the mechanical properties and geometrical precision of the final product. In order to capture and investigate these variations...... analysis is carried out using 3D quadratic elements which is a novel application for the numerical modelling of the pultrusion process. It is found that the 2D mechanical models give relatively reasonable and accurate stress and displacement evolutions in the transverse direction as compared to the 3D...

  3. Orbifold Reduction and 2d (0,2) Gauge Theories

    CERN Document Server

    Franco, Sebastian; Seong, Rak-Kyeong

    2016-01-01

    We introduce Orbifold Reduction, a new method for generating $2d$ $(0,2)$ gauge theories associated to D1-branes probing singular toric Calabi-Yau 4-folds starting from $4d$ $\\mathcal{N}=1$ gauge theories on D3-branes probing toric Calabi-Yau 3-folds. The new procedure generalizes dimensional reduction and orbifolding. In terms of T-dual configurations, it generates brane brick models starting from brane tilings. Orbifold reduction provides an agile approach for generating $2d$ $(0,2)$ theories with a brane realization. We present three practical applications of the new algorithm: the connection between $4d$ Seiberg duality and $2d$ triality, a combinatorial method for generating theories related by triality and a $2d$ $(0,2)$ generalization of the Klebanov-Witten mass deformation.

  4. Emerging and potential opportunities for 2D flexible nanoelectronics

    Science.gov (United States)

    Zhu, Weinan; Park, Saungeun; Akinwande, Deji

    2016-05-01

    The last 10 years have seen the emergence of two-dimensional (2D) nanomaterials such as graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BP) among the growing portfolio of layered van der Waals thin films. Graphene, the prototypical 2D material has advanced rapidly in device, circuit and system studies that has resulted in commercial large-area applications. In this work, we provide a perspective of the emerging and potential translational applications of 2D materials including semiconductors, semimetals, and insulators that comprise the basic material set for diverse nanosystems. Applications include RF transceivers, smart systems, the so-called internet of things, and neurotechnology. We will review the DC and RF electronic performance of graphene and BP thin film transistors. 2D materials at sub-um channel length have so far enabled cut-off frequencies from baseband to 100GHz suitable for low-power RF and sub-THz concepts.

  5. Double resonance rotational spectroscopy of CH2D+

    Science.gov (United States)

    Töpfer, Matthias; Jusko, Pavol; Schlemmer, Stephan; Asvany, Oskar

    2016-09-01

    Context. Deuterated forms of CH are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. There is no unambiguous detection of CH2D+ in space to date. Aims: Four submillimetre rotational lines of CH2D+ are documented in the literature. Our aim is to present a complete dataset of highly resolved rotational lines, including millimetre (mm) lines needed for a potential detection. Methods: We used a low-temperature ion trap and applied a novel IR-mm-wave double resonance method to measure the rotational lines of CH2D+. Results: We measured 21 low-lying (J ≤ 4) rotational transitions of CH2D+ between 23 GHz and 1.1 THz with accuracies close to 2 ppb.

  6. 2D gels still have a niche in proteomics

    DEFF Research Database (Denmark)

    Rogowska-Wrzesinska, Adelina; Le Bihan, Marie-Catherine; Thaysen-Andersen, Morten;

    2013-01-01

    With the rapid advance of MS-based proteomics one might think that 2D gel-based proteomics is dead. This is far from the truth. Current research has shown that there are still a number of places in the field of protein and molecular biology where 2D gels still play a leading role. The aim...... of this review is to highlight some of these applications. Examples from our own research as well as from other published works are used to illustrate the 2D gel driven research in the areas of: 1) de novo sequencing and protein identification from organisms with no or incomplete genome sequences available; 2......) alternative detection methods for modification specific proteomics; 3) identification of protein isoforms and modified proteins. With an example of the glycoprotein TIMP-1 protein we illustrate the unique properties of 2D gels for the separation and characterisation of multiply modified proteins. We also show...

  7. Technical Review of the UNET2D Hydraulic Model

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, William A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Richmond, Marshall C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2009-05-18

    The Kansas City District of the US Army Corps of Engineers is engaged in a broad range of river management projects that require knowledge of spatially-varied hydraulic conditions such as velocities and water surface elevations. This information is needed to design new structures, improve existing operations, and assess aquatic habitat. Two-dimensional (2D) depth-averaged numerical hydraulic models are a common tool that can be used to provide velocity and depth information. Kansas City District is currently using a specific 2D model, UNET2D, that has been developed to meet the needs of their river engineering applications. This report documents a tech- nical review of UNET2D.

  8. Illumination Compensation for 2-D Barcode Recognition Basing Morphologic

    Directory of Open Access Journals (Sweden)

    Jian-Hua Li

    2013-04-01

    Full Text Available Improvement of image quality has been highly demanded in digital imaging systems. This study presents a novel illumination normalization approach for 2-D barcode recognition under varying lighting conditions. MMs (Morphological transformations are employed to original images using big scale multiple SEs (structuring elements. Then we make use of entropy to fuse images. The performance of proposed methodology is illustrated through the processing of images with different kinds of 2-D barcodes under different backgrounds. The experimental results show that this approach can process different kinds of 2-D barcodes under varying lighting conditions adaptively. Compared with other conventional methods, our proposed approach does a better job in processing 2-D barcode under non-uniform illumination.

  9. Recent developments in 2D layered inorganic nanomaterials for sensing

    Science.gov (United States)

    Kannan, Padmanathan Karthick; Late, Dattatray J.; Morgan, Hywel; Rout, Chandra Sekhar

    2015-08-01

    Two dimensional layered inorganic nanomaterials (2D-LINs) have recently attracted huge interest because of their unique thickness dependent physical and chemical properties and potential technological applications. The properties of these layered materials can be tuned via both physical and chemical processes. Some 2D layered inorganic nanomaterials like MoS2, WS2 and SnS2 have been recently developed and employed in various applications, including new sensors because of their layer-dependent electrical properties. This article presents a comprehensive overview of recent developments in the application of 2D layered inorganic nanomaterials as sensors. Some of the salient features of 2D materials for different sensing applications are discussed, including gas sensing, electrochemical sensing, SERS and biosensing, SERS sensing and photodetection. The working principles of the sensors are also discussed together with examples.

  10. Holographic method for site-resolved detection of a 2D array of ultracold atoms

    CERN Document Server

    Hoffmann, Daniel Kai; Limmer, Wolfgang; Denschlag, Johannes Hecker

    2016-01-01

    We propose a novel approach to site-resolved detection of a 2D gas of ultracold atoms in an optical lattice. A near resonant laser beam is coherently scattered by the atomic array and its interference pattern is holographically recorded by superimposing it with a reference laser beam on a CCD chip. Fourier transformation of the recorded intensity pattern reconstructs the atomic distribution in the lattice with single-site resolution. The holographic detection method requires only a few hundred scattered photons per atom in order to achieve a high reconstruction fidelity. Therefore, additional cooling during detection might not be necessary even for light atomic elements such as lithium.

  11. 2d quantum gravity and black hole formation

    International Nuclear Information System (INIS)

    The quantum integral of generic 2d quantum gravity can be performed exactly. The equivalence of dilaton theories to 2d theories with torsion and the use of a light cone gauge are crucial. Scalar matter can be treated perturbatively. A generalization of the Polyakov action emerges. For scattering of scalars in a flat background already in the tree approximation for the first time the intermediate formation of a black hole is observed in an ab initio quantum gravity computation

  12. The Branching of Graphs in 2-d Quantum Gravity

    OpenAIRE

    Harris, M. G.

    1996-01-01

    The branching ratio is calculated for three different models of 2d gravity, using dynamical planar phi-cubed graphs. These models are pure gravity, the D=-2 Gaussian model coupled to gravity and the single spin Ising model coupled to gravity. The ratio gives a measure of how branched the graphs dominating the partition function are. Hence it can be used to estimate the location of the branched polymer phase for the multiple Ising model coupled to 2d gravity.

  13. Illumination Compensation for 2-D Barcode Recognition Basing Morphologic

    OpenAIRE

    Jian-Hua Li; Yi-Wen Wang; Yi Chen; Meng Zhang

    2013-01-01

    Improvement of image quality has been highly demanded in digital imaging systems. This study presents a novel illumination normalization approach for 2-D barcode recognition under varying lighting conditions. MMs (Morphological transformations) are employed to original images using big scale multiple SEs (structuring elements). Then we make use of entropy to fuse images. The performance of proposed methodology is illustrated through the processing of images with different kinds of 2-D barcode...

  14. Collins Model and Phase Diagram of 2D Ternary System

    Institute of Scientific and Technical Information of China (English)

    XIE Chuan-Mei; CHEN Li-Rong

    2004-01-01

    The Collins model is introduced into the two-dimensional (2D) alternative ternary system having the Lennard-Jones (L-J) potential. The Gibbs free energy of this ternary system is calculated, and according to thermodynamic theory, a group of equations that determine the solid-liquid diagram of ternary system are derived, some isothermal sectional diagrams of the 2D ternary system are obtained. The results are quite similar to the behavior of three-dimensional substances.

  15. Chloroplast phylogenomic data from the green algal order Sphaeropleales (Chlorophyceae, Chlorophyta) reveal complex patterns of sequence evolution.

    Science.gov (United States)

    Fučíková, Karolina; Lewis, Paul O; Lewis, Louise A

    2016-05-01

    Chloroplast sequence data are widely used to infer phylogenies of plants and algae. With the increasing availability of complete chloroplast genome sequences, the opportunity arises to resolve ancient divergences that were heretofore problematic. On the flip side, properly analyzing large multi-gene data sets can be a major challenge, as these data may be riddled with systematic biases and conflicting signals. Our study contributes new data from nine complete and four fragmentary chloroplast genome sequences across the green algal order Sphaeropleales. Our phylogenetic analyses of a 56-gene data set show that analyzing these data on a nucleotide level yields a well-supported phylogeny - yet one that is quite different from a corresponding amino acid analysis. We offer some possible explanations for this conflict through a range of analyses of modified data sets. In addition, we characterize the newly sequenced genomes in terms of their structure and content, thereby further contributing to the knowledge of chloroplast genome evolution. PMID:26903036

  16. Distinct expression patterns of glycoprotein hormone subunits in the lophotrochozoan Aplysia: implications for the evolution of neuroendocrine systems in animals.

    Science.gov (United States)

    Heyland, Andreas; Plachetzki, David; Donelly, Evonne; Gunaratne, Dinuka; Bobkova, Yelena; Jacobson, John; Kohn, Andrea B; Moroz, Leonid L

    2012-11-01

    Glycoprotein hormones (GPHs) comprise a group of signaling molecules critical for major metabolic and reproductive functions. In vertebrates they include chorionic gonadotropin, LH, FSH, and TSH. The active hormones are characterized by heterodimerization between a common α and hormone-specific β subunit, which activate leucine-rich repeat-containing G protein coupled receptors. To date, genes referred to as GPHα2 and GPHβ5 have been the only glycoprotein hormone subunits identified in invertebrates, suggesting that other GPHα and GPHβ subunits diversified during vertebrate evolution. Still the functions of GPHα2 and GPHβ5 remain largely unknown for both vertebrates and invertebrates. To further understand the evolution and putative function of these subunits, we cloned and analyzed phylogenetically two glycoprotein subunits, AcaGPHα and AcaGPHβ, from the sea hare Aplysia californica. Model based three-dimensional predictions of AcaGPHβ confirm the presence of a complete cysteine knot, two hairpin loops, and a long loop. As in the human GPHβ5 subunit the seatbelt structure is absent in AcaGPHβ. We also found that AcaGPHα and AcaGPHβ subunits are expressed in larval stages of Aplysia, and we present a detailed expression map of the subunits in the adult central nervous system using in situ hybridizations. Both subunits are expressed in subpopulations of pleural and buccal mechanosensory neurons, suggesting a neuronal modulatory function of these subunits in Aplysia. Furthermore it supports the model of a relatively diffuse neuroendocrine-like system in molluscs, where specific primary sensory neurons release peptides extrasynaptically (paracrine secretion). This is in contrast to vertebrates and insects, in which releasing and stimulating factor from centralized sensory regions of the central nervous system ultimately regulate hormone release in peripheral glands.

  17. Cellular automaton model with dynamical 2D speed-gap relation reproduces empirical and experimental features of traffic flow

    CERN Document Server

    Tian, Junfang; Ma, Shoufeng; Zhu, Chenqiang; Jiang, Rui; Ding, YaoXian

    2015-01-01

    This paper proposes an improved cellular automaton traffic flow model based on the brake light model, which takes into account that the desired time gap of vehicles is remarkably larger than one second. Although the hypothetical steady state of vehicles in the deterministic limit corresponds to a unique relationship between speeds and gaps in the proposed model, the traffic states of vehicles dynamically span a two-dimensional region in the plane of speed versus gap, due to the various randomizations. It is shown that the model is able to well reproduce (i) the free flow, synchronized flow, jam as well as the transitions among the three phases; (ii) the evolution features of disturbances and the spatiotemporal patterns in a car-following platoon; (iii) the empirical time series of traffic speed obtained from NGSIM data. Therefore, we argue that a model can potentially reproduce the empirical and experimental features of traffic flow, provided that the traffic states are able to dynamically span a 2D speed-gap...

  18. Technique of Embedding Depth Maps into 2D Images

    Institute of Scientific and Technical Information of China (English)

    Kazutake Uehira; Hiroshi Unno; Youichi Takashima

    2014-01-01

    This paper proposes a new technique that is used to embed depth maps into corresponding 2-dimensional (2D) images. Since a 2D image and its depth map are integrated into one type of image format, they can be treated as if they were one 2D image. Thereby, it can reduce the amount of data in 3D images by half and simplify the processes for sending them through networks because the synchronization between images for the left and right eyes becomes unnecessary. We embed depth maps in the quantized discrete cosine transform (DCT) data of 2D images. The key to this technique is whether the depth maps could be embedded into 2D images without perceivably deteriorating their quality. We try to reduce their deterioration by compressing the depth map data by using the differences from the next pixel to the left. We assume that there is only one non-zero pixel at most on one horizontal line in the DCT block because the depth map values change abruptly. We conduct an experiment to evaluate the quality of the 2D images embedded with depth maps and find that satisfactory quality could be achieved.

  19. Retention, Molecular Evolution, and Expression Divergence of the Auxin/Indole Acetic Acid and Auxin Response Factor Gene Families in Brassica Rapa Shed Light on Their Evolution Patterns in Plants.

    Science.gov (United States)

    Huang, Zhinan; Duan, Weike; Song, Xiaoming; Tang, Jun; Wu, Peng; Zhang, Bei; Hou, Xilin

    2016-02-01

    Auxin/indole acetic acids (Aux/IAAs) and auxin response factors (ARFs), major components of the Aux signaling network, are involved in many developmental processes in plants. Investigating their evolution will provide new sight on the relationship between the molecular evolution of these genes and the increasing morphotypes of plants. We constructed comparative analyses of the retention, structure, expansion, and expression patterns of Aux/IAAs and ARFs in Brassica rapa and their evolution in eight other plant species, including algae, bryophytes, lycophytes, and angiosperms. All 33 of the ARFs, including 1 ARF-like (AL) (a type of ARF-like protein) and 53 Aux/IAAs, were identified in the B. rapa genome. The genes mainly diverged approximately 13 Ma. After the split, no Aux/IAA was completely lost, and they were more preferentially retained than ARFs. In land plants, compared with ARFs, which increased in stability, Aux/IAAs expanded more rapidly and were under more relaxed selective pressure. Moreover, BraIAAs were expressed in a more tissue-specific fashion than BraARFs and demonstrated functional diversification during gene duplication under different treatments, which enhanced the cooperative interaction of homologs to help plants adapt to complex environments. In addition, ALs existed widely and had a closer relationship with ARFs, suggesting that ALs might be the initial structure of ARFs. Our results suggest that the rapid expansion and preferential retention of Aux/IAAs are likely paralleled by the increasingly complex morphotypes in Brassicas and even in land plants. Meanwhile, the data support the hypothesis that the PB1 domain plays a key role in the origin of both Aux/IAAs and ARFs. PMID:26721260

  20. Retention, Molecular Evolution, and Expression Divergence of the Auxin/Indole Acetic Acid and Auxin Response Factor Gene Families in Brassica Rapa Shed Light on Their Evolution Patterns in Plants

    Science.gov (United States)

    Huang, Zhinan; Duan, Weike; Song, Xiaoming; Tang, Jun; Wu, Peng; Zhang, Bei; Hou, Xilin

    2016-01-01

    Auxin/indole acetic acids (Aux/IAAs) and auxin response factors (ARFs), major components of the Aux signaling network, are involved in many developmental processes in plants. Investigating their evolution will provide new sight on the relationship between the molecular evolution of these genes and the increasing morphotypes of plants. We constructed comparative analyses of the retention, structure, expansion, and expression patterns of Aux/IAAs and ARFs in Brassica rapa and their evolution in eight other plant species, including algae, bryophytes, lycophytes, and angiosperms. All 33 of the ARFs, including 1 ARF-like (AL) (a type of ARF-like protein) and 53 Aux/IAAs, were identified in the B. rapa genome. The genes mainly diverged approximately 13 Ma. After the split, no Aux/IAA was completely lost, and they were more preferentially retained than ARFs. In land plants, compared with ARFs, which increased in stability, Aux/IAAs expanded more rapidly and were under more relaxed selective pressure. Moreover, BraIAAs were expressed in a more tissue-specific fashion than BraARFs and demonstrated functional diversification during gene duplication under different treatments, which enhanced the cooperative interaction of homologs to help plants adapt to complex environments. In addition, ALs existed widely and had a closer relationship with ARFs, suggesting that ALs might be the initial structure of ARFs. Our results suggest that the rapid expansion and preferential retention of Aux/IAAs are likely paralleled by the increasingly complex morphotypes in Brassicas and even in land plants. Meanwhile, the data support the hypothesis that the PB1 domain plays a key role in the origin of both Aux/IAAs and ARFs. PMID:26721260

  1. Evaluation of low-dose limits in 3D-2D rigid registration for surgical guidance

    Science.gov (United States)

    Uneri, A.; Wang, A. S.; Otake, Y.; Kleinszig, G.; Vogt, S.; Khanna, A. J.; Gallia, G. L.; Gokaslan, Z. L.; Siewerdsen, J. H.

    2014-09-01

    An algorithm for intensity-based 3D-2D registration of CT and C-arm fluoroscopy is evaluated for use in surgical guidance, specifically considering the low-dose limits of the fluoroscopic x-ray projections. The registration method is based on a framework using the covariance matrix adaptation evolution strategy (CMA-ES) to identify the 3D patient pose that maximizes the gradient information similarity metric. Registration performance was evaluated in an anthropomorphic head phantom emulating intracranial neurosurgery, using target registration error (TRE) to characterize accuracy and robustness in terms of 95% confidence upper bound in comparison to that of an infrared surgical tracking system. Three clinical scenarios were considered: (1) single-view image + guidance, wherein a single x-ray projection is used for visualization and 3D-2D guidance; (2) dual-view image + guidance, wherein one projection is acquired for visualization, combined with a second (lower-dose) projection acquired at a different C-arm angle for 3D-2D guidance; and (3) dual-view guidance, wherein both projections are acquired at low dose for the purpose of 3D-2D guidance alone (not visualization). In each case, registration accuracy was evaluated as a function of the entrance surface dose associated with the projection view(s). Results indicate that images acquired at a dose as low as 4 μGy (approximately one-tenth the dose of a typical fluoroscopic frame) were sufficient to provide TRE comparable or superior to that of conventional surgical tracking, allowing 3D-2D guidance at a level of dose that is at most 10% greater than conventional fluoroscopy (scenario #2) and potentially reducing the dose to approximately 20% of the level in a conventional fluoroscopically guided procedure (scenario #3).

  2. Intercalation of organic molecules in 2D copper (II) nitroprusside: Intermolecular interactions and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Osiry, H.; Cano, A.; Lemus-Santana, A.A.; Rodríguez, A. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional (Mexico); Carbonio, R.E. [INFIQC-CONICET, Departamento de Físico Química, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba (Argentina); Reguera, E., E-mail: edilso.reguera@gmail.com [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional (Mexico)

    2015-10-15

    This contribution discusses the intercalation of imidazole and its 2-ethyl derivative, and pyridine in 2D copper nitroprusside. In the interlayer region, neighboring molecules remain interacting throu gh their dipole and quadrupole moments, which supports the solid 3D crystal structure. The crystal structure of this series of intercalation compounds was solved and refined from powder X-ray diffraction patterns complemented with spectroscopic information. The intermolecular interactions were studied from the refined crystal structures and low temperature magnetic measurements. Due to strong attractive forces between neighboring molecules, the resulting π–π cloud overlapping enables the ferromagnetic coupling between metal centers on neighboring layers, which was actually observed for the solids containing imidazole and pyridine as intercalated molecules. For these two solids, the magnetic data were properly described with a model of six neighbors. For the solid containing 2-ethylimidazole and for 2D copper nitroprusside, a model of four neighbors in a plane is sufficient to obtain a reliable data fitting. - Highlights: • Intercalation of organic molecules in 2D copper (II) nitroprusside. • Molecular properties of intercalation compounds of 2D copper (II) nitroprusside. • Magnetic properties of hybrid inorganic–organic solids. • Hybrid inorganic–organic 3D framework.

  3. Sparse Non-negative Tensor 2D Deconvolution (SNTF2D) for multi channel time-frequency analysis

    DEFF Research Database (Denmark)

    Mørup, Morten; Schmidt, Mikkel N.

    2006-01-01

    We recently introduced two algorithms for sparse non-negative matrix factor 2-D deconvolution (SNMF2D) that are useful for single channel source separation and music transcription. We here extend this approach to the analysis of the log-frequency spectrograms of a multichannel recording. The model...... algorithms are demonstrated to successfully identify the components of both artificially generated as well as real stereo music....

  4. Phylogeography, Interaction Patterns and the Evolution of Host Choice in Drosophila-Parasitoid Systems in Ryukyu Archipelago and Taiwan.

    Directory of Open Access Journals (Sweden)

    Biljana Novković

    Full Text Available Island biotas provide a great opportunity to study not only the phylogeographic patterns of a group of species, but also to explore the differentiation in their coevolutionary interactions. Drosophila and their parasitoids are exemplary systems for studying complex interaction patterns. However, there is a lack of studies combining interaction-based and molecular marker-based methods. We applied an integrated approach combining phylogeography, interaction, and host-choice behavior studies, with the aim to understand how coevolutionary interactions evolve in Drosophila-parasitoid island populations. The study focused on the three most abundant Drosophila species in Ryukyu archipelago and Taiwan: D. albomicans, D. bipectinata, and D. takahashii, and the Drosophila-parasitoid Leptopilina ryukyuensis. We determined mitochondrial COI haplotypes for samples representing five island populations of Drosophila and four island populations of L. ryukyuensis. We additionally sequenced parts of the autosomal Gpdh for Drosophila samples, and the ITS2 for parasitoid samples. Phylogenetic and coalescent analyses were used to test for demographic events and to place them in a temporal framework. Geographical differences in Drosophila-parasitoid interactions were studied in host-acceptance, host-suitability, and host-choice experiments. All four species showed species-specific phylogeographic patterns. A general trend of the haplotype diversity increasing towards the south was observed. D. albomicans showed very high COI haplotype diversity, and had the most phylogeographically structured populations, with differentiation into the northern and the southern population-group, divided by the Kerama gap. Differentiation in host suitability was observed only between highly structured populations of D. albomicans, possibly facilitated by restricted gene flow. Differentiation in host-acceptance in D. takahashii, and host-acceptance and host-choice in L. ryukyuensis was

  5. Phylogeography, Interaction Patterns and the Evolution of Host Choice in Drosophila-Parasitoid Systems in Ryukyu Archipelago and Taiwan.

    Science.gov (United States)

    Novković, Biljana; Kimura, Masahito T

    2015-01-01

    Island biotas provide a great opportunity to study not only the phylogeographic patterns of a group of species, but also to explore the differentiation in their coevolutionary interactions. Drosophila and their parasitoids are exemplary systems for studying complex interaction patterns. However, there is a lack of studies combining interaction-based and molecular marker-based methods. We applied an integrated approach combining phylogeography, interaction, and host-choice behavior studies, with the aim to understand how coevolutionary interactions evolve in Drosophila-parasitoid island populations. The study focused on the three most abundant Drosophila species in Ryukyu archipelago and Taiwan: D. albomicans, D. bipectinata, and D. takahashii, and the Drosophila-parasitoid Leptopilina ryukyuensis. We determined mitochondrial COI haplotypes for samples representing five island populations of Drosophila and four island populations of L. ryukyuensis. We additionally sequenced parts of the autosomal Gpdh for Drosophila samples, and the ITS2 for parasitoid samples. Phylogenetic and coalescent analyses were used to test for demographic events and to place them in a temporal framework. Geographical differences in Drosophila-parasitoid interactions were studied in host-acceptance, host-suitability, and host-choice experiments. All four species showed species-specific phylogeographic patterns. A general trend of the haplotype diversity increasing towards the south was observed. D. albomicans showed very high COI haplotype diversity, and had the most phylogeographically structured populations, with differentiation into the northern and the southern population-group, divided by the Kerama gap. Differentiation in host suitability was observed only between highly structured populations of D. albomicans, possibly facilitated by restricted gene flow. Differentiation in host-acceptance in D. takahashii, and host-acceptance and host-choice in L. ryukyuensis was found, despite there

  6. Wind patterns as a potential driver in the evolution and maintenance of a North American migratory suture zone.

    Science.gov (United States)

    McCabe, Jennifer D; Olsen, Brian J; Hiebeler, David

    2016-09-01

    Suture zones are areas where range contact zones and hybrid zones of multiple taxa are clustered. Migratory divides, contact zones between divergent populations that breed adjacent to one another but use different migratory routes, are a particular case of suture zones. Although multiple hypotheses for both the formation and maintenance of migratory divides have been suggested, quantitative tests are scarce. Here, we tested whether a novel factor, prevailing winds, was sufficient to explain both the evolution and maintenance of the Cordilleran migratory divide using individual-based models. Empirical observations of eastern birds suggest a circuitous migratory route across Canada before heading south. Western breeders, however, travel south along the Pacific coast to their wintering grounds. We modeled the effect of wind on bird migratory flights by allowing them to float at elevation using spatially explicit modeled wind data. Modeled eastern birds had easterly mean trajectories, whereas western breeders showed significantly more southern trajectories. We also determined that a mean airspeed of 18.5 m s(-1) would be necessary to eliminate this difference in trajectory, a speed that is achieved by waterfowl and shorebirds, but is faster than songbird flight speeds. These results lend support for the potential importance of wind in shaping the phylogeographic history of North American songbirds.

  7. Classic Maya bloodletting and the cultural evolution of religious rituals: quantifying patterns of variation in hieroglyphic texts.

    Science.gov (United States)

    Munson, Jessica; Amati, Viviana; Collard, Mark; Macri, Martha J

    2014-01-01

    Religious rituals that are painful or highly stressful are hypothesized to be costly signs of commitment essential for the evolution of complex society. Yet few studies have investigated how such extreme ritual practices were culturally transmitted in past societies. Here, we report the first study to analyze temporal and spatial variation in bloodletting rituals recorded in Classic Maya (ca. 250-900 CE) hieroglyphic texts. We also identify the sociopolitical contexts most closely associated with these ancient recorded rituals. Sampling an extensive record of 2,480 hieroglyphic texts, this study identifies every recorded instance of the logographic sign for the word ch'ahb' that is associated with ritual bloodletting. We show that documented rituals exhibit low frequency whose occurrence cannot be predicted by spatial location. Conversely, network ties better capture the distribution of bloodletting rituals across the southern Maya region. Our results indicate that bloodletting rituals by Maya nobles were not uniformly recorded, but were typically documented in association with antagonistic statements and may have signaled royal commitments among connected polities.

  8. Molecular characterization and developmental expression pattern of the chicken apolipoprotein D gene: implications for the evolution of vertebrate lipocalins.

    Science.gov (United States)

    Ganfornina, María D; Sánchez, Diego; Pagano, Aldo; Tonachini, Laura; Descalzi-Cancedda, Fiorella; Martínez, Salvador

    2005-01-01

    The insect Lazarillo and the mammalian apolipoprotein D (ApoD) are orthologous members of the lipocalin protein family. We report the cloning and embryonic expression of chicken ApoD, the first molecularly characterized nonmammalian ApoD. We also report the ApoD expression in mouse during postnatal development and some novel aspects of the expression of the paralogous lipocalin prostaglandin D-synthase (PGDS) and discuss these results in view of the lipocalin family evolution in vertebrates. ApoD is expressed in subsets of central nervous system (CNS) neurons and glia during late chicken embryogenesis. Contrary to mouse ApoD, no expression appears in neural crest-derived cephalic mesenchyme and blood vessel pericytes. Also, ApoD is expressed in developing chicken feathers. These expressions are corroborated by quantitative reverse transcriptase-polymerase chain reaction profiles. ApoD is expressed during mouse postnatal development in a subset of CNS neurons, astrocytes and oligodendrocytes, but also in meninges and pericytes. Chicken PGDS is expressed in brain meninges and perivascular cells. Our results suggest that the amniote last common ancestor expressed ApoD and PGDS in the brain during embryogenesis. ApoD appears restricted to ectodermal derivatives, whereas PGDS is expressed by derivatives of the three germ layers.

  9. IGUANA A high-performance 2D and 3D visualisation system

    CERN Document Server

    Alverson, G; Muzaffar, S; Osborne, I; Taylor, L; Tuura, L A

    2004-01-01

    The IGUANA project has developed visualisation tools for multiple high-energy experiments. At the core of IGUANA is a generic, high- performance visualisation system based on OpenInventor and OpenGL. This paper describes the back-end and a feature-rich 3D visualisation system built on it, as well as a new 2D visualisation system that can automatically generate 2D views from 3D data, for example to produce R/Z or X/Y detector displays from existing 3D display with little effort. IGUANA has collaborated with the open-source gl2ps project to create a high-quality vector postscript output that can produce true vector graphics output from any OpenGL 2D or 3D display, complete with surface shading and culling of invisible surfaces. We describe how it works. We also describe how one can measure the memory and performance costs of various OpenInventor constructs and how to test scene graphs. We present good patterns to follow and bad patterns to avoid. We have added more advanced tools such as per-object clipping, sl...

  10. 2D nanostructures for water purification: graphene and beyond.

    Science.gov (United States)

    Dervin, Saoirse; Dionysiou, Dionysios D; Pillai, Suresh C

    2016-08-18

    Owing to their atomically thin structure, large surface area and mechanical strength, 2D nanoporous materials are considered to be suitable alternatives for existing desalination and water purification membrane materials. Recent progress in the development of nanoporous graphene based materials has generated enormous potential for water purification technologies. Progress in the development of nanoporous graphene and graphene oxide (GO) membranes, the mechanism of graphene molecular sieve action, structural design, hydrophilic nature, mechanical strength and antifouling properties and the principal challenges associated with nanopore generation are discussed in detail. Subsequently, the recent applications and performance of newly developed 2D materials such as 2D boron nitride (BN) nanosheets, graphyne, molybdenum disulfide (MoS2), tungsten chalcogenides (WS2) and titanium carbide (Ti3C2Tx) are highlighted. In addition, the challenges affecting 2D nanostructures for water purification are highlighted and their applications in the water purification industry are discussed. Though only a few 2D materials have been explored so far for water treatment applications, this emerging field of research is set to attract a great deal of attention in the near future. PMID:27506268

  11. Failure Mechanism of True 2D Granular Flows

    CERN Document Server

    Nguyen, Cuong T; Fukagawa, R

    2015-01-01

    Most previous experimental investigations of two-dimensional (2D) granular column collapses have been conducted using three-dimensional (3D) granular materials in narrow horizontal channels (i.e., quasi-2D condition). Our recent research on 2D granular column collapses by using 2D granular materials (i.e., aluminum rods) has revealed results that differ markedly from those reported in the literature. We assume a 2D column with an initial height of h0 and initial width of d0, a defined as their ratio (a =h0/d0), a final height of h , and maximum run-out distance of d . The experimental data suggest that for the low a regime (a 0.65), the ratio of a to (d-d0)/d0, h0/h , or d/d0 is expressed by power-law relations. In particular, the following power-function ratios (h0/h=1.42a^2/3 and d/d0=4.30a^0.72) are proposed for every a >0.65. In contrast, the ratio (d-d0)/d0=3.25a^0.96 only holds for 0.651.5. In addition, the influence of ground contact surfaces (hard or soft beds) on the final run-out distance and destru...

  12. The NH$_2$D hyperfine structure revealed by astrophysical observations

    CERN Document Server

    Daniel, F; Punanova, A; Harju, J; Faure, A; Roueff, E; Sipilä, O; Caselli, P; Güsten, R; Pon, A; Pineda, J E

    2016-01-01

    The 1$_{11}$-1$_{01}$ lines of ortho and para--NH$_2$D (o/p-NH$_2$D), respectively at 86 and 110 GHz, are commonly observed to provide constraints on the deuterium fractionation in the interstellar medium. In cold regions, the hyperfine structure due to the nitrogen ($^{14}$N) nucleus is resolved. To date, this splitting is the only one which is taken into account in the NH$_2$D column density estimates. We investigate how the inclusion of the hyperfine splitting caused by the deuterium (D) nucleus affects the analysis of the rotational lines of NH$_2$D. We present 30m IRAM observations of the above mentioned lines, as well as APEX o/p-NH$_2$D observations of the 1$_{01}$-0$_{00}$ lines at 333 GHz. The hyperfine spectra are first analyzed with a line list that only includes the hyperfine splitting due to the $^{14}$N nucleus. We find inconsistencies between the line widths of the 1$_{01}$-0$_{00}$ and 1$_{11}$-1$_{01}$ lines, the latter being larger by a factor of $\\sim$1.6$\\pm0.3$. Such a large difference is...

  13. Ultrafast 2D NMR: An Emerging Tool in Analytical Spectroscopy

    Science.gov (United States)

    Giraudeau, Patrick; Frydman, Lucio

    2014-06-01

    Two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy is widely used in chemical and biochemical analyses. Multidimensional NMR is also witnessing increased use in quantitative and metabolic screening applications. Conventional 2D NMR experiments, however, are affected by inherently long acquisition durations, arising from their need to sample the frequencies involved along their indirect domains in an incremented, scan-by-scan nature. A decade ago, a so-called ultrafast (UF) approach was proposed, capable of delivering arbitrary 2D NMR spectra involving any kind of homo- or heteronuclear correlation, in a single scan. During the intervening years, the performance of this subsecond 2D NMR methodology has been greatly improved, and UF 2D NMR is rapidly becoming a powerful analytical tool experiencing an expanded scope of applications. This review summarizes the principles and main developments that have contributed to the success of this approach and focuses on applications that have been recently demonstrated in various areas of analytical chemistry—from the real-time monitoring of chemical and biochemical processes, to extensions in hyphenated techniques and in quantitative applications.

  14. Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity.

    Science.gov (United States)

    Lyons, Robert P; Scholz, Christopher A; Cohen, Andrew S; King, John W; Brown, Erik T; Ivory, Sarah J; Johnson, Thomas C; Deino, Alan L; Reinthal, Peter N; McGlue, Michael M; Blome, Margaret W

    2015-12-22

    The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9-15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world's largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species. PMID:26644580

  15. An amphioxus Gli gene reveals conservation of midline patterning and the evolution of hedgehog signalling diversity in chordates.

    Directory of Open Access Journals (Sweden)

    Sebastian M Shimeld

    Full Text Available BACKGROUND: Hedgehog signalling, interpreted in receiving cells by Gli transcription factors, plays a central role in the development of vertebrate and Drosophila embryos. Many aspects of the signalling pathway are conserved between these lineages, however vertebrates have diverged in at least one key aspect: they have evolved multiple Gli genes encoding functionally-distinct proteins, increasing the complexity of the hedgehog-dependent transcriptional response. Amphioxus is one of the closest living relatives of the vertebrates, having split from the vertebrate lineage prior to the widespread gene duplication prominent in early vertebrate evolution. PRINCIPAL FINDINGS: We show that amphioxus has a single Gli gene, which is deployed in tissues adjacent to sources of hedgehog signalling derived from the midline and anterior endoderm. This shows the duplication and divergence of the Gli gene family, and hence the origin of vertebrate Gli functional diversity, was specific to the vertebrate lineage. However we also show that the single amphioxus Gli gene produces two distinct transcripts encoding different proteins. We utilise three tests of Gli function to examine the transcription regulatory capacities of these different proteins, demonstrating one has activating activity similar to Gli2, while the other acts as a weak repressor, similar to Gli3. CONCLUSIONS: These data show that vertebrates and amphioxus have evolved functionally-similar repertoires of Gli proteins using parallel molecular routes; vertebrates via gene duplication and divergence, and amphioxus via alternate splicing of a single gene. Our results demonstrate that similar functional complexity of intercellular signalling can be achieved via different evolutionary pathways.

  16. Distinct co-evolution patterns of genes associated to DNA polymerase III DnaE and PolC

    Directory of Open Access Journals (Sweden)

    Engelen Stefan

    2012-02-01

    Full Text Available Abstract Background Bacterial genomes displaying a strong bias between the leading and the lagging strand of DNA replication encode two DNA polymerases III, DnaE and PolC, rather than a single one. Replication is a highly unsymmetrical process, and the presence of two polymerases is therefore not unexpected. Using comparative genomics, we explored whether other processes have evolved in parallel with each polymerase. Results Extending previous in silico heuristics for the analysis of gene co-evolution, we analyzed the function of genes clustering with dnaE and polC. Clusters were highly informative. DnaE co-evolves with the ribosome, the transcription machinery, the core of intermediary metabolism enzymes. It is also connected to the energy-saving enzyme necessary for RNA degradation, polynucleotide phosphorylase. Most of the proteins of this co-evolving set belong to the persistent set in bacterial proteomes, that is fairly ubiquitously distributed. In contrast, PolC co-evolves with RNA degradation enzymes that are present only in the A+T-rich Firmicutes clade, suggesting at least two origins for the degradosome. Conclusion DNA replication involves two machineries, DnaE and PolC. DnaE co-evolves with the core functions of bacterial life. In contrast PolC co-evolves with a set of RNA degradation enzymes that does not derive from the degradosome identified in gamma-Proteobacteria. This suggests that at least two independent RNA degradation pathways existed in the progenote community at the end of the RNA genome world.

  17. Heterochromatin patterns and ribosomal DNA loci distribution in diploid and polyploid Crotalaria species (Leguminosae, Papilionoideae), and inferences on karyotype evolution.

    Science.gov (United States)

    Mondin, Mateus; Aguiar-Perecin, Margarida L R

    2011-09-01

    Most Crotalaria species display a symmetric karyotype with 2n = 16, but 2n = 14 is found in Chrysocalycinae subsection Incanae and 2n = 32 in American species of the section Calycinae. Seven species of the sections Chrysocalycinae, Calycinae, and Crotalaria were analyzed for the identification of heterochromatin types with GC- and AT-specific fluorochromes and chromosomal location of ribosomal DNA loci using fluorescent in situ hybridization (FISH). A major 45S rDNA locus was observed on chromosome 1 in all the species, and a variable number of minor ones were revealed. Only one 5S rDNA locus was observed in the species investigated. Chromomycin A(3) (CMA) revealed CMA(+) bands colocalized with most rDNA loci, small bands unrelated to ribosomal DNA on two chromosome pairs in Crotalaria incana, and CMA(+) centromeric bands that were quenched by distamycin A were detected in species of Calycinae and Crotalaria sections. DAPI(+) bands were detected in C. incana. The results support the species relationships based on flower specialization and were useful for providing insight into mechanisms of karyotype evolution. The heterochromatin types revealed by fluorochromes suggest the occurrence of rearrangements in repetitive DNA families in these heterochromatic blocks during species diversification. This DNA sequence turnover and the variability in number/position of rDNA sites could be interpreted as resulting from unequal crossing over and (or) transposition events. The occurrence of only one 5S rDNA locus and the smaller chromosome size in the polyploids suggest that DNA sequence losses took place following polyploidization events.

  18. Heterochromatin patterns and ribosomal DNA loci distribution in diploid and polyploid Crotalaria species (Leguminosae, Papilionoideae), and inferences on karyotype evolution.

    Science.gov (United States)

    Mondin, Mateus; Aguiar-Perecin, Margarida L R

    2011-09-01

    Most Crotalaria species display a symmetric karyotype with 2n = 16, but 2n = 14 is found in Chrysocalycinae subsection Incanae and 2n = 32 in American species of the section Calycinae. Seven species of the sections Chrysocalycinae, Calycinae, and Crotalaria were analyzed for the identification of heterochromatin types with GC- and AT-specific fluorochromes and chromosomal location of ribosomal DNA loci using fluorescent in situ hybridization (FISH). A major 45S rDNA locus was observed on chromosome 1 in all the species, and a variable number of minor ones were revealed. Only one 5S rDNA locus was observed in the species investigated. Chromomycin A(3) (CMA) revealed CMA(+) bands colocalized with most rDNA loci, small bands unrelated to ribosomal DNA on two chromosome pairs in Crotalaria incana, and CMA(+) centromeric bands that were quenched by distamycin A were detected in species of Calycinae and Crotalaria sections. DAPI(+) bands were detected in C. incana. The results support the species relationships based on flower specialization and were useful for providing insight into mechanisms of karyotype evolution. The heterochromatin types revealed by fluorochromes suggest the occurrence of rearrangements in repetitive DNA families in these heterochromatic blocks during species diversification. This DNA sequence turnover and the variability in number/position of rDNA sites could be interpreted as resulting from unequal crossing over and (or) transposition events. The occurrence of only one 5S rDNA locus and the smaller chromosome size in the polyploids suggest that DNA sequence losses took place following polyploidization events. PMID:21864195

  19. Continuous 1.3-million-year record of East African hydroclimate, and implications for patterns of evolution and biodiversity

    Science.gov (United States)

    Lyons, Robert P.; Scholz, Christopher A.; Cohen, Andrew S.; King, John W.; Brown, Erik T.; Ivory, Sarah J.; Johnson, Thomas C.; Deino, Alan L.; Reinthal, Peter N.; McGlue, Michael M.; Blome, Margaret W.

    2015-12-01

    The transport of moisture in the tropics is a critical process for the global energy budget and on geologic timescales, has markedly influenced continental landscapes, migratory pathways, and biological evolution. Here we present a continuous, first-of-its-kind 1.3-My record of continental hydroclimate and lake-level variability derived from drill core data from Lake Malawi, East Africa (9-15° S). Over the Quaternary, we observe dramatic shifts in effective moisture, resulting in large-scale changes in one of the world's largest lakes and most diverse freshwater ecosystems. Results show evidence for 24 lake level drops of more than 200 m during the Late Quaternary, including 15 lowstands when water levels were more than 400 m lower than modern. A dramatic shift is observed at the Mid-Pleistocene Transition (MPT), consistent with far-field climate forcing, which separates vastly different hydroclimate regimes before and after ∼800,000 years ago. Before 800 ka, lake levels were lower, indicating a climate drier than today, and water levels changed frequently. Following the MPT high-amplitude lake level variations dominate the record. From 800 to 100 ka, a deep, often overfilled lake occupied the basin, indicating a wetter climate, but these highstands were interrupted by prolonged intervals of extreme drought. Periods of high lake level are observed during times of high eccentricity. The extreme hydroclimate variability exerted a profound influence on the Lake Malawi endemic cichlid fish species flock; the geographically extensive habitat reconfiguration provided novel ecological opportunities, enabling new populations to differentiate rapidly to distinct species.

  20. Patterning of the dorsal-ventral axis in echinoderms: insights into the evolution of the BMP-chordin signaling network.

    Directory of Open Access Journals (Sweden)

    François Lapraz

    2009-11-01

    Full Text Available Formation of the dorsal-ventral axis of the sea urchin embryo relies on cell interactions initiated by the TGFbeta Nodal. Intriguingly, although nodal expression is restricted to the ventral side of the embryo, Nodal function is required for specification of both the ventral and the dorsal territories and is able to restore both ventral and dorsal regions in nodal morpholino injected embryos. The molecular basis for the long-range organizing activity of Nodal is not understood. In this paper, we provide evidence that the long-range organizing activity of Nodal is assured by a relay molecule synthesized in the ventral ectoderm, then translocated to the opposite side of the embryo. We identified this relay molecule as BMP2/4 based on the following arguments. First, blocking BMP2/4 function eliminated the long-range organizing activity of an activated Nodal receptor in an axis rescue assay. Second, we demonstrate that BMP2/4 and the corresponding type I receptor Alk3/6 functions are both essential for specification of the dorsal region of the embryo. Third, using anti-phospho-Smad1/5/8 immunostaining, we show that, despite its ventral transcription, the BMP2/4 ligand triggers receptor mediated signaling exclusively on the dorsal side of the embryo, one of the most extreme cases of BMP translocation described so far. We further report that the pattern of pSmad1/5/8 is graded along the dorsal-ventral axis and that two BMP2/4 target genes are expressed in nested patterns centered on the region with highest levels of pSmad1/5/8, strongly suggesting that BMP2/4 is acting as a morphogen. We also describe the very unusual ventral co-expression of chordin and bmp2/4 downstream of Nodal and demonstrate that Chordin is largely responsible for the spatial restriction of BMP2/4 signaling to the dorsal side. Thus, unlike in most organisms, in the sea urchin, a single ventral signaling centre is responsible for induction of ventral and dorsal cell fates. Finally

  1. Evolution of central pattern generators for the control of a five-link planar bipedal walking mechanism

    CERN Document Server

    Baydin, Atilim Gunes

    2008-01-01

    With the aim of producing a stable human-like bipedal gait, a five-link planar walking mechanism was coupled with a central pattern generator (CPG) network, consisting of units based on Matsuoka's half-center oscillator model. As a minimalistic approach to bipedal walking, this type of walking mechanism contains only four actuators (two in the hip joints and two in the knee joints), and is lacking feet and ankles. Firstly, the mechanism was designed and built as a physical simulation programmed from scratch, providing a platform for hand-tuned tests and the creation of a CPG controller by genetic algorithms (GA). The oscillatory characteristics of the CPG network together with its internal connection structure and the feedback pathways from the environment were subject to GA optimization. The approach proved successful and the results were then transferred to a hardware realization of the five-link walking mechanism, to test how well these perform under real-world dynamics. Results suggest that the biological...

  2. Soil evolution dynamics and cultural response: Transformation of habitation patterns in NW Europe (3000-1000 yrs BP)

    Science.gov (United States)

    Kluiving, Sjoerd; Roymans, Nico; Bekkema, Marijke

    2014-05-01

    Long-term archaeological data gathering in the southern Netherlands delivers an interesting scale model that may be tested on the Pleistocene sand areas of the Northwest European Plain. On a micro-scale level it has become clear that Bronze Age and Iron Age farmers intensively used the landscape, resulting in relatively dense distribution patterns of settlements all over the sand plateaus. However, this agricultural use of the landscape - related to the 'celtic field' system - led to a process of soil degeneration during which initially brown moder podzols gradually transformed into degenerated humus podzols that could no longer be used as farmland. Measured loam values of over 250 soil samples of 5 case studies in the southern Netherlands, are in general agreement with the described model that the plaggen cover is located on soils containing high loam% and that humus podzolsoils of former heath areas have low loam content. Local spatial as well as vertical variations in loam content of sand layers are warning against single parameter research. Other potential causes for the deviation of the model are: a) impact of fluctuating groundwater, b) grain size and transmissivity of the sediments, c) organic matter content, d) land management and e) palaeo-climate change. Also studies from nearby NW European Pleistocene sand areas will be presented that show deviations and similarities with the shifting habitation model in the past due to soil degradation.

  3. 2D materials for photon conversion and nanophotonics

    Science.gov (United States)

    Tahersima, Mohammad H.; Sorger, Volker J.

    2015-09-01

    The field of two-dimensional (2D) materials has the potential to enable unique applications across a wide range of the electromagnetic spectrum. While 2D-layered materials hold promise for next-generation photon-conversion intrinsic limitations and challenges exist that shall be overcome. Here we discuss the intrinsic limitations as well as application opportunities of this new class of materials, and is sponsored by the NSF program Designing Materials to Revolutionize and Engineer our Future (DMREF) program, which links to the President's Materials Genome Initiative. We present general material-related details for photon conversion, and show that taking advantage of the mechanical flexibility of 2D materials by rolling MoS2/graphene/hexagonal boron nitride stack to a spiral solar cell allows for solar absorption up to 90%.

  4. Graphene based 2D-materials for supercapacitors

    Science.gov (United States)

    Palaniselvam, Thangavelu; Baek, Jong-Beom

    2015-09-01

    Ever-increasing energy demands and the depletion of fossil fuels are compelling humanity toward the development of suitable electrochemical energy conversion and storage devices to attain a more sustainable society with adequate renewable energy and zero environmental pollution. In this regard, supercapacitors are being contemplated as potential energy storage devices to afford cleaner, environmentally friendly energy. Recently, a great deal of attention has been paid to two-dimensional (2D) nanomaterials, including 2D graphene and its inorganic analogues (transition metal double layer hydroxides, chalcogenides, etc), as potential electrodes for the development of supercapacitors with high electrochemical performance. This review provides an overview of the recent progress in using these graphene-based 2D materials as potential electrodes for supercapacitors. In addition, future research trends including notable challenges and opportunities are also discussed.

  5. Simultaneous 2D Strain Sensing Using Polymer Planar Bragg Gratings

    Directory of Open Access Journals (Sweden)

    Manuel Rosenberger

    2015-02-01

    Full Text Available We demonstrate the application of polymer planar Bragg gratings for multi-axial strain sensing and particularly highlight simultaneous 2D strain measurement. A polymer planar Bragg grating (PPBG fabricated with a single writing step in bulk polymethylmethacrylate is used for measuring both tensile and compressive strain at various angles. It is shown that the sensitivity of the PPBG strongly depends on the angle between the optical waveguide into which the grating is inscribed and the direction along which the mechanical load is applied. Additionally, a 2D PPBG fabricated by writing two Bragg gratings angularly displaced from each other into a single polymer platelet is bonded to a stainless steel plate. The two reflected wavelengths exhibit different sensitivities while tested toward tensile and compressive strain. These characteristics make 2D PPBG suitable for measuring multi-axial tensile and compressive strain.

  6. Cluster algebras in Scattering Amplitudes with special 2D kinematics

    CERN Document Server

    Torres, Marcus A C

    2013-01-01

    We study the cluster algebra of the kinematic configuration space $Conf_n(\\mathbb{P}^3)$ of a n-particle scattering amplitude restricted to the special 2D kinematics. We found that the n-points two loop MHV remainder function found in special 2D kinematics depend on a selection of \\XX-coordinates that are part of a special structure of the cluster algebra related to snake triangulations of polygons. This structure forms a necklace of hypercubes beads in the corresponding Stasheff polytope. Furthermore in $n = 12$, the cluster algebra and the selection of \\XX-coordinates in special 2D kinematics replicates the cluster algebra and the selection of \\XX-coordinates of $n=6$ two loop MHV amplitude in 4D kinematics.

  7. UPLAND EROSION MODELING WITH CASC2D-SED

    Institute of Scientific and Technical Information of China (English)

    Pierre JULIEN; Rosalía ROJAS

    2002-01-01

    Developed at Colorado State University, CASC2D-SED is a physically-based model simulating the hydrologic response of a watershed to a distributed rainfall field. The time-dependent processes include:precipitation, interception, infiltration, surface runoff and channel routing, upland erosion, transport and sedimentation. CASC2D-SED is applied to Goodwin Creek, Mississippi. The watershed covers 21 km2and has been extensively monitored both at the outlet and at several internal locations by the ARS-NSL at Oxford, MS. The model has been calibrated and validated using rainfall data from 16 meteorological stations, 6 stream gauging stations and 6 sediment gauging stations. Sediment erosion/deposition rates by size fraction are predicted both in space and time. Geovisualization, a powerful data exploration technique based on GIS technology, is used to analyze and display the dynamic output time series generated by the CASC2D-SED model.

  8. Design and Realization of Dynamic Obstacle on URWPSSim2D

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2013-07-01

    Full Text Available Simulation system is charged with the strategy validation and dual team meets, and as the 2-dimensional simulation platform for underwater robotic fish game, URWPGSim2D is the assigned platform for Chinese underwater robot contest and Robot cup underwater program. By now on URWPGSim2D, there is only static obstacles,thus short of changeableness. In order to improve the changeableness and innovation of robotic fish contest, to extend the space for the programming of contest strategy, and to increase the interest, this paper study the design of dynamic obstacles on URWPGSim2D, and design and implement two kinds of dynamic obstacles, which are the evadible dynamic obstacle and the forcing dribbling obstacle.  

  9. 2D bifurcations and Newtonian properties of memristive Chua's circuits

    Science.gov (United States)

    Marszalek, W.; Podhaisky, H.

    2016-01-01

    Two interesting properties of Chua's circuits are presented. First, two-parameter bifurcation diagrams of Chua's oscillatory circuits with memristors are presented. To obtain various 2D bifurcation images a substantial numerical effort, possibly with parallel computations, is needed. The numerical algorithm is described first and its numerical code for 2D bifurcation image creation is available for free downloading. Several color 2D images and the corresponding 1D greyscale bifurcation diagrams are included. Secondly, Chua's circuits are linked to Newton's law φ ''= F(t,φ,φ')/m with φ=\\text{flux} , constant m > 0, and the force term F(t,φ,φ') containing memory terms. Finally, the jounce scalar equations for Chua's circuits are also discussed.

  10. Creating bio-inspired hierarchical 3D-2D photonic stacks via planar lithography on self-assembled inverse opals

    CERN Document Server

    Burgess, Ian B; Loncar, Marko

    2012-01-01

    Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top-down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top-down and bottom-up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly, Parides sesostris. These fabrication procedures, combining advantages of both top-down and bottom-up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D-2D photonic crystal devices.

  11. Creating bio-inspired hierarchical 3D–2D photonic stacks via planar lithography on self-assembled inverse opals

    International Nuclear Information System (INIS)

    Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top–down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top–down and bottom–up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly, Parides sesostris. These fabrication procedures, combining advantages of both top–down and bottom–up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D–2D photonic crystal devices. (paper)

  12. Elastomeric 2D Grating and Hemispherical Optofluidic Chamber for Multifunctional Fluidic Sensing

    CERN Document Server

    Xu, Zhida

    2014-01-01

    We present an optofluidic sensor based on an elastomeric two-dimensional (2D) grating integrated inside a hemispherical fluid chamber. Laser beam is diffracted before (reflection) and after (transmission) going through the grating and liquid in the dome chamber. The sensing mechanism is investigated and simulated with a finite difference time domain (FDTD) based electromagnetic (EM) method. For experiment, by analyzing the size, power and shape of the 2D diffraction patterns, we can retrieve multiple parameters of the liquid including the refractive index, pressure and opacity with high sensitivity. We demonstrate that glucose concentration can be monitored when mixed in different concentrated phosphate buffered saline (PBS) solution. The free-solution binding of bovine serum albumin (BSA) and anti-BSA IgG is detected with this optical sensor. This low-cost, multifunctional and reliable optofluidic sensor has the potential to be used as monitor of biofluid such as blood in hemodialysis.

  13. Tracking objects outside the line of sight using 2D intensity images

    Science.gov (United States)

    Klein, Jonathan; Peters, Christoph; Martín, Jaime; Laurenzis, Martin; Hullin, Matthias B.

    2016-08-01

    The observation of objects located in inaccessible regions is a recurring challenge in a wide variety of important applications. Recent work has shown that using rare and expensive optical setups, indirect diffuse light reflections can be used to reconstruct objects and two-dimensional (2D) patterns around a corner. Here we show that occluded objects can be tracked in real time using much simpler means, namely a standard 2D camera and a laser pointer. Our method fundamentally differs from previous solutions by approaching the problem in an analysis-by-synthesis sense. By repeatedly simulating light transport through the scene, we determine the set of object parameters that most closely fits the measured intensity distribution. We experimentally demonstrate that this approach is capable of following the translation of unknown objects, and translation and orientation of a known object, in real time.

  14. Characterization of Seed Storage Proteins from Chickpea Using 2D Electrophoresis Coupled with Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Pramod Kumar Singh

    2016-01-01

    Full Text Available Proteomic analysis was employed to map the seed storage protein network in landrace and cultivated chickpea accessions. Protein extracts were separated by two-dimensional gel electrophoresis (2D-GE across a broad range 3.0–10.0 immobilized pH gradient (IPG strips. Comparative elucidation of differentially expressed proteins between two diverse geographically originated chickpea accessions was carried out using 2D-GE coupled with mass spectrometry. A total of 600 protein spots were detected in these accessions. In-gel protein expression patterns revealed three protein spots as upregulated and three other as downregulated. Using trypsin in-gel digestion, these differentially expressed proteins were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS which showed 45% amino acid homology of chickpea seed storage proteins with Arabidopsis thaliana.

  15. Characterization of Seed Storage Proteins from Chickpea Using 2D Electrophoresis Coupled with Mass Spectrometry.

    Science.gov (United States)

    Singh, Pramod Kumar; Shrivastava, Nidhi; Chaturvedi, Krishna; Sharma, Bechan; Bhagyawant, Sameer S

    2016-01-01

    Proteomic analysis was employed to map the seed storage protein network in landrace and cultivated chickpea accessions. Protein extracts were separated by two-dimensional gel electrophoresis (2D-GE) across a broad range 3.0-10.0 immobilized pH gradient (IPG) strips. Comparative elucidation of differentially expressed proteins between two diverse geographically originated chickpea accessions was carried out using 2D-GE coupled with mass spectrometry. A total of 600 protein spots were detected in these accessions. In-gel protein expression patterns revealed three protein spots as upregulated and three other as downregulated. Using trypsin in-gel digestion, these differentially expressed proteins were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) which showed 45% amino acid homology of chickpea seed storage proteins with Arabidopsis thaliana. PMID:27144024

  16. A Neural-FEM tool for the 2-D magnetic hysteresis modeling

    Science.gov (United States)

    Cardelli, E.; Faba, A.; Laudani, A.; Lozito, G. M.; Riganti Fulginei, F.; Salvini, A.

    2016-04-01

    The aim of this work is to present a new tool for the analysis of magnetic field problems considering 2-D magnetic hysteresis. In particular, this tool makes use of the Finite Element Method to solve the magnetic field problem in real device, and fruitfully exploits a neural network (NN) for the modeling of 2-D magnetic hysteresis of materials. The NS has as input the magnetic inductions components B at the k-th simulation step and returns as output the corresponding values of the magnetic field H corresponding to the input pattern. It is trained by vector measurements performed on the magnetic material to be modeled. This input/output scheme is directly implemented in a FEM code employing the magnetic potential vector A formulation. Validations through measurements on a real device have been performed.

  17. W$_{\\infty}$ structures of 2D string theory

    CERN Document Server

    Hamada, K J

    1996-01-01

    The Ward identities of the W_{\\infty} symmetry in 2D string theory in the tachyon background are studied in the continuum approach. Comparing the solutions with the matrix model results, it is verified that 2D string amplitudes are different from the matrix model amplitudes only by the external leg factors even in higher genus. This talk is based on the recent work [1] and also [2] for the c_M <1 model. (Talk given at the workshop on ``Frontiers in Quantum Field Theory'', Osaka, Japan, December 1995.)

  18. CH2D+, the Search for the Holy Grail

    Science.gov (United States)

    Roueff, Evelyne; Gerin, Maryvonne; Lis, Dariusz C.; Wootten, Alwyn; Marcelino, Nuria; Cernicharo, Jose; Tercero, Belen

    2013-10-01

    CH2D+, the singly deuterated counterpart of CH3+, offers an alternative way to mediate formation of deuterated species at temperatures of several tens of Kelvin, as compared to the release of deuterated species from grains. We report a longstanding observational search for this molecular ion, whose rotational spectroscopy is not yet completely secure. We summarize the main spectroscopic properties of this molecule and discuss the chemical network leading to the formation of CH2D+, with explicit account of the ortho/para forms of H2, H3+, and CH3+. Astrochemical models support the presence of this molecular ion in moderately warm environments at a marginal level.

  19. Isotropic 2D quadrangle meshing with size and orientation control

    KAUST Repository

    Pellenard, Bertrand

    2011-12-01

    We propose an approach for automatically generating isotropic 2D quadrangle meshes from arbitrary domains with a fine control over sizing and orientation of the elements. At the heart of our algorithm is an optimization procedure that, from a coarse initial tiling of the 2D domain, enforces each of the desirable mesh quality criteria (size, shape, orientation, degree, regularity) one at a time, in an order designed not to undo previous enhancements. Our experiments demonstrate how well our resulting quadrangle meshes conform to a wide range of input sizing and orientation fields.

  20. Design of the LRP airfoil series using 2D CFD

    DEFF Research Database (Denmark)

    Zahle, Frederik; Bak, Christian; Sørensen, Niels N.;

    2014-01-01

    This paper describes the design and wind tunnel testing of a high-Reynolds number, high lift airfoil series designed for wind turbines. The airfoils were designed using direct gradient- based numerical multi-point optimization based on a Bezier parameterization of the shape, coupled to the 2D...... Navier-Stokes flow solver EllipSys2D. The resulting airfoils, the LRP2-30 and LRP2-36, achieve both higher operational lift coefficients and higher lift to drag ratios compared to the equivalent FFA-W3 airfoils....

  1. EEG simulation by 2D interconnected chaotic oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Kubany, Adam, E-mail: adamku@bgu.ac.i [Department of Industrial Engineering and Management, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel); Mhabary, Ziv; Gontar, Vladimir [Department of Industrial Engineering and Management, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel)

    2011-01-15

    Research highlights: ANN of 2D interconnected chaotic oscillators is explored for EEG simulation. An inverse problem solution (PRCGA) is proposed. Good matching between the simulated and experimental EEG signals has been achieved. - Abstract: An artificial neuronal network composed by 2D interconnected chaotic oscillators is explored for brain waves (EEG) simulation. For the inverse problem solution a parallel real-coded genetic algorithm (PRCGA) is proposed. In order to conduct thorough comparison between the simulated and target signal characteristics, a spectrum analysis of the signals is undertaken. A good matching between the theoretical and experimental EEG signals has been achieved. Numerical results of calculations are presented and discussed.

  2. Self-dual Strings and 2D SYM

    CERN Document Server

    Hosomichi, Kazuo

    2014-01-01

    We study the system of M2-branes suspended between parallel M5-branes using ABJM model with a natural half-BPS boundary condition. For small separation between M5-branes, the worldvolume theory is shown to reduce to a 2D N=(4,4) super Yang-Mills theory with some similarity to q-deformed Yang-Mills theory. The gauge coupling is related to the position of the branes in an interesting manner. The theory is considerably different from the 2D theory proposed for multiple "M-strings". We make a detailed comparison of elliptic genus of the two descriptions and find only a partial agreement.

  3. EEG simulation by 2D interconnected chaotic oscillators

    International Nuclear Information System (INIS)

    Research highlights: → ANN of 2D interconnected chaotic oscillators is explored for EEG simulation. → An inverse problem solution (PRCGA) is proposed. → Good matching between the simulated and experimental EEG signals has been achieved. - Abstract: An artificial neuronal network composed by 2D interconnected chaotic oscillators is explored for brain waves (EEG) simulation. For the inverse problem solution a parallel real-coded genetic algorithm (PRCGA) is proposed. In order to conduct thorough comparison between the simulated and target signal characteristics, a spectrum analysis of the signals is undertaken. A good matching between the theoretical and experimental EEG signals has been achieved. Numerical results of calculations are presented and discussed.

  4. Quantum process tomography by 2D fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pachón, Leonardo A. [Grupo de Física Atómica y Molecular, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Andrew H. [Department of Chemistry and Biochemistry, Oregon Center for Optics, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 (United States); Aspuru-Guzik, Alán [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-06-07

    Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

  5. CH2D+, the Search for the Holy Grail

    CERN Document Server

    Roueff, E; Lis, D C; Wootten, A; Marcelino, N; cernicharo, J; Tercero, B

    2013-01-01

    CH2D+, the singly deuterated counterpart of CH3+, offers an alternative way to mediate formation of deuterated species at temperatures of several tens of K, as compared to the release of deuterated species from grains. We report a longstanding observational search for this molecular ion, whose rotational spectroscopy is not yet completely secure. We summarize the main spectroscopic properties of this molecule and discuss the chemical network leading to the formation of CH2D+, with explicit account of the ortho/para forms of H2, H3+ and CH3+. Astrochemical models support the presence of this molecular ion in moderately warm environments at a marginal level.

  6. GENERALIZED VARIATIONAL OPTIMAZATION ANALYSIS FOR 2-D FLOW FIELD

    Institute of Scientific and Technical Information of China (English)

    HUANG Si-xun; XU Ding-hua; LAN Wei-ren; TENG Jia-jun

    2005-01-01

    The Variational Optimization Analysis Method (VOAM) for 2-D flow field suggested by Sasaki was reviewed first. It is known that the VOAM can be used efficiently in most cases. However, in the cases where there are high frequency noises in 2-D flow field, it appears to be inefficient. In the present paper, based on Sasaki's VOAM, a Generalized Variational Optimization Analysis Method (GVOAM) was proposed with regularization ideas, which could deal well with flow fields containing high frequency noises. A numerical test shows that observational data can be both variationally optimized and filtered, and therefore the GVOAM is an efficient method.

  7. QSAR Models for P-450 (2D6) Substrate Activity

    DEFF Research Database (Denmark)

    Ringsted, Tine; Nikolov, Nikolai Georgiev; Jensen, Gunde Egeskov;

    2009-01-01

    drugs and other chemicals. A training set of 747 chemicals primarily based on in vivo human data for the CYP isoenzyme 2D6 was collected from the literature. QSAR models focusing on substrate/non substrate activity were constructed by the use of MultiCASE, Leadscope and MDL quantitative structure......Human Cytochrome P450 (CYP) is a large group of enzymes that possess an essential function in metabolising different exogenous and endogenous compounds. Humans have more than 50 different genes encoding CYP enzymes, among these a gene encoding for the CYP isoenzyme 2D6, a CYP able to metabolise...

  8. SKIMO: corto de animación 2D

    OpenAIRE

    VALERO BALLESTER, AIDA AMPARO

    2015-01-01

    El siguiente Trabajo Final de Grado llamado “Skimo” consiste en un teaser de animación 2D enfocado a ser finalizado el próximo año durante la realización del Diploma en Animación de personajes 2D del Máster de animación. Realizado en solitario como reto personal durante el curso presente, siendo la primera vez que trabajaba la animación. Para este proyecto he realizado toda la preproducción (layout, animática, storyboard, diseño de personajes, fondos, etc), animación en pape...

  9. Transmission properties of 2D metamaterial photonic crystals

    Science.gov (United States)

    Mejía-Salazar, Jorge; Porras-Montenegro, Nelson

    2014-03-01

    By using the finite difference time domain technique, we have performed a theoretical study of the transmission properties in 2D photonic crystals composed by circular cilyndrical metamaterial rods. Numerical transmission spectra was compared with its corresponding photonic band structure in the case of an infinite periodic 2D array obtaining a very good agreement. On the other hand, we have characterized the corresponding symmetries for this system and the results were compared with its corresponding conventional plasmonic metamaterial counterpart. J.R. M-S is funded by the Colombian Agency COLCIENCIAS.

  10. Nomenclature for human CYP2D6 alleles.

    Science.gov (United States)

    Daly, A K; Brockmöller, J; Broly, F; Eichelbaum, M; Evans, W E; Gonzalez, F J; Huang, J D; Idle, J R; Ingelman-Sundberg, M; Ishizaki, T; Jacqz-Aigrain, E; Meyer, U A; Nebert, D W; Steen, V M; Wolf, C R; Zanger, U M

    1996-06-01

    To standardize CYP2D6 allele nomenclature, and to conform with international human gene nomenclature guidelines, an alternative to the current arbitrary system is described. Based on recommendations for human genome nomenclature, we propose that alleles be designated by CYP2D6 followed by an asterisk and a combination of roman letters and arabic numerals distinct for each allele with the number specifying the key mutation and, where appropriate, a letter specifying additional mutations. Criteria for classification as a separate allele and protein nomenclature are also presented. PMID:8807658

  11. To move or to evolve: contrasting patterns of intercontinental connectivity and climatic niche evolution in "Terebinthaceae" (Anacardiaceae and Burseraceae.

    Directory of Open Access Journals (Sweden)

    Andrea eWeeks

    2014-11-01

    Full Text Available Many angiosperm families are distributed pantropically, yet for any given continent little is known about which lineages are ancient residents or recent arrivals. Here we use a comprehensive sampling of the pantropical sister pair Anacardiaceae and Burseraceae to assess the relative importance of continental vicariance, long-distance dispersal and niche-conservatism in generating its distinctive pattern of diversity over time. Each family has approximately the same number of species and identical stem age, yet Anacardiaceae display a broader range of fruit morphologies and dispersal strategies and include species that can withstand freezing temperatures, whereas Burseraceae do not. We found that nuclear and chloroplast data yielded a highly supported phylogenetic reconstruction that supports current taxonomic concepts and time-calibrated biogeographic reconstructions that are broadly congruent with the fossil record. We conclude that the most recent common ancestor of these families was widespread and likely distributed in the Northern Hemisphere during the Cretaceous and that vicariance between Eastern and Western Hemispheres coincided with the initial divergence of the families. The tempo of diversification of the families is strikingly different. Anacardiaceae steadily accumulated lineages starting in the Late Cretaceous–Paleocene while the majority of Burseraceae diversification occurred in the Miocene. Multiple dispersal- and vicariance-based intercontinental colonization events are inferred for both families throughout the past 100 million years. However, Anacardiaceae have shifted climatic niches frequently during this time, while Burseraceae have experienced very few shifts between dry and wet climates and only in the tropics. Thus, we conclude that both Anacardiaceae and Burseraceae move easily but that Anacardiaceae have adapted more often, either due to more varied selective pressures or greater intrinsic lability.

  12. Discrete tomographic reconstruction of 2D polycrystal orientation maps from X-ray diffraction projections using Gibbs priors

    DEFF Research Database (Denmark)

    Rodek, L.; Knudsen, E.; Poulsen, H.F.;

    2005-01-01

    The determination of crystalline structures is a demanding and fundamental task of crystallography. This paper offers a new approach for rendering a 2D grain map of a polycrystal based on an orientation map reconstructed from X-ray diffraction patterns. The orientation map is produced by a Bayesian...

  13. Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS gene expression patterns

    Directory of Open Access Journals (Sweden)

    Abercrombie Jason M

    2011-07-01

    and pollen-specific functions in early seed plants and was then recruited to novel expression patterns and functions within pollen tube walls in an ancestor of extant angiosperms.

  14. CYP2D6基因与药物代谢%CYP2D6 gene and drug metabolism

    Institute of Scientific and Technical Information of China (English)

    施安国

    2003-01-01

    细胞色素P-450(CYP)中的CYP2D6酶在抗抑郁药、安定药及某些抗心律失常药的代谢中起重要作用,CYP2D6基因位于22号常染色体上为隐性遗传,CYP2D6基因呈多态性约有70余种等位基因变异型,也存在特异人群差别,因而导致所编码的酶活性不同,这些数据有助于理解药物代谢的个体差异、有助于预测药物之间的相互作用.

  15. Adaptive reorganization of 2D molecular nanoporous network induced by coadsorbed guest molecule.

    Science.gov (United States)

    Zheng, Qing-Na; Wang, Lei; Zhong, Yu-Wu; Liu, Xuan-He; Chen, Ting; Yan, Hui-Juan; Wang, Dong; Yao, Jian-Nian; Wan, Li-Jun

    2014-03-25

    The ordered array of nanovoids in nanoporous networks, such as honeycomb, Kagome, and square, provides a molecular template for the accommodation of "guest molecules". Compared with the commonly studied guest molecules featuring high symmetry evenly incorporated into the template, guest molecules featuring lower symmetry are rare to report. Herein, we report the formation of a distinct patterned superlattice of guest molecules by selective trapping of guest molecules into the honeycomb network of trimesic acid (TMA). Two distinct surface patterns have been achieved by the guest inclusion induced adaptive reconstruction of a 2D molecular nanoporous network. The honeycomb networks can synergetically tune the arrangement upon inclusion of the guest molecules with different core size but similar peripherals groups, resulting in a trihexagonal Kagome or triangular patterns.

  16. Influence of Isotope Effects on Product Polarizations of N(2D)+D2,N(2D)+H2 and N(2D)+HD Reactive Systems

    Institute of Scientific and Technical Information of China (English)

    NIE Shan-shan; CHU Tian-shu

    2012-01-01

    To figure out the influence of isotope effect on product polarizations of the N(2D)+D2 reactive system and its isotope variants,quasi-classical trajectory(QCT) calculation was performed on Ho's potential energy surfacc(PES) of 2A" state.Product polarizations such as product distributions ofP(θr),P(φr) and P(θr,φr),as well as the generalized polarization-dependent differential cross sections(PDDCSs) were discussed and compared in detail among the four product channels of the title reactions.Both the intermolecular and intramolecular isotope effects were proved to be influential on product polarizations.

  17. Wilson loop in 2d noncommutative gauge theories

    OpenAIRE

    Valtancoli, Paolo

    2009-01-01

    We reconsider the perturbative expansion of the Wilson loop in 2d noncommutative gauge theories, using an improved integration method. For the class of maximally crossed diagrams in the $\\theta \\to \\infty$ limit we find an intriguing formula, easily generalizable to all orders in perturbation theory.

  18. The 2dF Galaxy Redshift Survey: Preliminary Results

    OpenAIRE

    Maddox, S.

    1997-01-01

    Spectroscopic observations for a new survey of 250 000 galaxy redshifts are underway, using the 2dF instrument at the AAT. The input galaxy catalogue and commissioning data are described. The first result from the preliminary data is a new estimate of the galaxy luminosity function at =0.1.

  19. H on He: sticking and 2d-superfluidity

    International Nuclear Information System (INIS)

    The sticking coefficient, which governs the sticking time τs, is discussed for high surface-coverage conditions. We point out that τs must remain large compared to a characteristic vortex diffusion time, if the system is to display 2d-superfluidity

  20. 2D Static Light Scattering for Dairy Based Applications

    DEFF Research Database (Denmark)

    Skytte, Jacob Lercke

    Throughout this thesis we investigate a recently introduced optical technique denoted 2D static light scattering (2DSLS). The technique is remote sensing, non-invasive, highly flexible, and appears to be well suited for in-line process control. Moreover, the output signal contains contributions...