WorldWideScience

Sample records for random walker evolving

  1. Quincke random walkers

    Science.gov (United States)

    Pradillo, Gerardo; Heintz, Aneesh; Vlahovska, Petia

    2017-11-01

    The spontaneous rotation of a sphere in an applied uniform DC electric field (Quincke effect) has been utilized to engineer self-propelled particles: if the sphere is initially resting on a surface, it rolls. The Quincke rollers have been widely used as a model system to study collective behavior in ``active'' suspensions. If the applied field is DC, an isolated Quincke roller follows a straight line trajectory. In this talk, we discuss the design of a Quincke roller that executes a random-walk-like behavior. We utilize AC field - upon reversal of the field direction a fluctuation in the axis of rotation (which is degenerate in the plane perpendicular to the field and parallel to the surface) introduces randomness in the direction of motion. The MSD of an isolated Quincke walker depends on frequency, amplitude, and waveform of the electric field. Experiment and theory are compared. We also investigate the collective behavior of Quincke walkers,the transport of inert particles in a bath of Quincke walkers, and the spontaneous motion of a drop containing Quincke active particle. supported by NSF Grant CBET 1437545.

  2. MUSCLE MRI SEGMENTATION USING RANDOM WALKER METHOD

    Directory of Open Access Journals (Sweden)

    A. V. Shukelovich

    2013-01-01

    Full Text Available A technique of marker set construction for muscle MRI segmentation using random walker approach is introduced. The possibility of clinician’s manual labor amount reduction and random walker algorithm optimization is studied.

  3. Passive random walkers and riverlike networks on growing surfaces.

    Science.gov (United States)

    Chin, Chen-Shan

    2002-08-01

    Passive random walker dynamics is introduced on a growing surface. The walker is designed to drift upward or downward and then follow specific topological features, such as hill tops or valley bottoms, of the fluctuating surface. The passive random walker can thus be used to directly explore scaling properties of otherwise somewhat hidden topological features. For example, the walker allows us to directly measure the dynamical exponent of the underlying growth dynamics. We use the Kardar-Parisi-Zhang (KPZ) -type surface growth as an example. The world lines of a set of merging passive walkers show nontrivial coalescence behaviors and display the riverlike network structures of surface ridges in space-time. In other dynamics, such as Edwards-Wilkinson growth, this does not happen. The passive random walkers in KPZ-type surface growth are closely related to the shock waves in the noiseless Burgers equation. We also briefly discuss their relations to the passive scalar dynamics in turbulence.

  4. Asymmetric evolving random networks

    Science.gov (United States)

    Coulomb, S.; Bauer, M.

    2003-10-01

    We generalize the Poissonian evolving random graph model of M. Bauer and D. Bernard (2003), to deal with arbitrary degree distributions. The motivation comes from biological networks, which are well-known to exhibit non Poissonian degree distributions. A node is added at each time step and is connected to the rest of the graph by oriented edges emerging from older nodes. This leads to a statistical asymmetry between incoming and outgoing edges. The law for the number of new edges at each time step is fixed but arbitrary. Thermodynamical behavior is expected when this law has a large time limit. Although (by construction) the incoming degree distributions depend on this law, this is not the case for most qualitative features concerning the size distribution of connected components, as long as the law has a finite variance. As the variance grows above 1/4, the average being < 1/2, a giant component emerges, which connects a finite fraction of the vertices. Below this threshold, the distribution of component sizes decreases algebraically with a continuously varying exponent. The transition is of infinite order, in sharp contrast with the case of static graphs. The local-in-time profiles for the components of finite size allow to give a refined description of the system.

  5. Evolving Random Forest for Preference Learning

    DEFF Research Database (Denmark)

    Abou-Zleikha, Mohamed; Shaker, Noor

    2015-01-01

    This paper introduces a novel approach for pairwise preference learning through a combination of an evolutionary method and random forest. Grammatical evolution is used to describe the structure of the trees in the Random Forest (RF) and to handle the process of evolution. Evolved random forests ...... obtained for predicting pairwise self-reports of users for the three emotional states engagement, frustration and challenge show very promising results that are comparable and in some cases superior to those obtained from state-of-the-art methods....

  6. Random Walker Coverage Analysis for Information Dissemination in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Konstantinos Skiadopoulos

    2017-06-01

    Full Text Available The increasing technological progress in electronics provides network nodes with new and enhanced capabilities that allow the revisit of the traditional information dissemination (and collection problem. The probabilistic nature of information dissemination using random walkers is exploited here to deal with challenges imposed by unconventional modern environments. In such systems, node operation is not deterministic (e.g., does not depend only on network nodes’ battery, but it rather depends on the particulars of the ambient environment (e.g., in the case of energy harvesting: sunshine, wind. The mechanism of information dissemination using one random walker is studied and analyzed in this paper under a different and novel perspective. In particular, it takes into account the stochastic nature of random walks, enabling further understanding of network coverage. A novel and original analysis is presented, which reveals the evolution network coverage by a random walker with respect to time. The derived analytical results reveal certain additional interesting aspects regarding network coverage, thus shedding more light on the random walker mechanism. Further analytical results, regarding the walker’s spatial movement and its associated neighborhood, are also confirmed through experimentation. Finally, simulation results considering random geometric graph topologies, which are suitable for modeling mobile environments, support and confirm the analytical findings.

  7. Random walker and the telegrapher's equation: A paradigm of a generalized hydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Rosenau, P. (Department of Mechanical Engineering, Technion, Haifa 32000 (Israel) Center for Nonlinear Studies, MS-B258, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

    1993-08-01

    The telegrapher's equation (TE) is the continuum limit of a persisting random walker. We find that the TE reproduces the original spectrum almost exactly for all wavelengths---far beyond the validity of the expansion. This surprising property is used as a paradigm towards the derivation of a generalized hydrodynamics. Applications to other problems are explored.

  8. Effective trapping of random walkers in complex networks.

    Science.gov (United States)

    Hwang, S; Lee, D-S; Kahng, B

    2012-04-01

    Exploring the World Wide Web has become one of the key issues in information science, specifically in view of its application to the PageRank-like algorithms used in search engines. The random walk approach has been employed to study such a problem. The probability of return to the origin (RTO) of random walks is inversely related to how information can be accessed during random surfing. We find analytically that the RTO probability for a given starting node shows a crossover from a slow to a fast decay behavior with time and the crossover time increases with the degree of the starting node. We remark that the RTO probability becomes almost constant in the early-time regime as the degree exponent approaches two. This result indicates that a random surfer can be effectively trapped at the hub and supports the necessity of the random jump strategy empirically used in the Google's search engine.

  9. On the number of common sites visited by N random walkers

    CERN Document Server

    Turban, L

    2016-01-01

    Majumdar and Tamm [Phys. Rev. E 86 021135 (2012), arXiv:1206.6184] recently obtained analytical expressions for the mean number of common sites W_N(t) visited up to time t by N independent random walkers starting from the origin of a d-dimensional lattice. In this short note I show how the different regimes and the corresponding asymptotic power laws can be retrieved using the notion of fractal intersection.

  10. Coupled uncertainty provided by a multifractal random walker

    Energy Technology Data Exchange (ETDEWEB)

    Koohi Lai, Z. [Department of Physics, Firoozkooh Branch, Islamic Azad University, Firoozkooh (Iran, Islamic Republic of); Vasheghani Farahani, S. [Department of Physics, Tafresh University, P.O. Box 39518-79611, Tafresh (Iran, Islamic Republic of); Movahed, S.M.S. [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); The Abdus Salam International Centre for Theoretical Physics, Strada Costiera, 11, Trieste 34151 (Italy); Jafari, G.R., E-mail: g_jafari@sbu.ac.ir [Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of)

    2015-10-09

    The aim here is to study the concept of pairing multifractality between time series possessing non-Gaussian distributions. The increasing number of rare events creates “criticality”. We show how the pairing between two series is affected by rare events, which we call “coupled criticality”. A method is proposed for studying the coupled criticality born out of the interaction between two series, using the bivariate multifractal random walk (BiMRW). This method allows studying dependence of the coupled criticality on the criticality of each individual system. This approach is applied to data sets of gold and oil markets, and inflation and unemployment. - Highlights: • The coupled criticality between two systems is modeled by the bivariate multifractal random walk. • This coupled criticality is generally directed. • This coupled criticality is inversely proportional to the criticality of either of the systems. • The coupled criticality can emerge when at least one of the systems posses a Gaussian distribution.

  11. Encounter distribution of two random walkers on a finite one-dimensional interval

    Energy Technology Data Exchange (ETDEWEB)

    Tejedor, Vincent; Schad, Michaela; Metzler, Ralf [Physics Department, Technical University of Munich, James Franck Strasse, 85747 Garching (Germany); Benichou, Olivier; Voituriez, Raphael, E-mail: metz@ph.tum.de [Laboratoire de Physique Theorique de la Matiere Condensee (UMR 7600), Universite Pierre et Marie Curie, 4 Place Jussieu, 75255 Paris Cedex (France)

    2011-09-30

    We analyse the first-passage properties of two random walkers confined to a finite one-dimensional domain. For the case of absorbing boundaries at the endpoints of the interval, we derive the probability that the two particles meet before either one of them becomes absorbed at one of the boundaries. For the case of reflecting boundaries, we obtain the mean first encounter time of the two particles. Our approach leads to closed-form expressions that are more easily tractable than a previously derived solution in terms of the Weierstrass' elliptic function. (paper)

  12. Integrability and tau-functions on Random Walkers & Isomonodromy Deformation Systems

    Science.gov (United States)

    Saenz Rodriguez, Axel Ivan

    We consider three types of integrable models which happen to lie under the classification of random walkers or isomonodromic deformations. We deal with an infinite queue that moves forward at random times, indecisive walkers on a circle walking left with probability p and walking right with probability 1-p at any given time, and a deformation of a matrix multi-valued holomorphic function on the projective line which preserves the monodromy structure of the function. Particularly, we work with the Plancherel growth process where we write the Schur generating function and show that it is a KP tau-function. Also, we work with the asymmetric simple exclusion process (ASEP) on a finite ring lattice and prove that the Bethe ansatz gives a complete set of eigenfunctions for generic parameters. Lastly, we write a solution and the tau-function to the Painleve 1 isomonodromy system using the Eynard-Orantin topological recursion. Additionally, we include an introductory background for integrable systems and an appendix that gives a resolution of a family of singular maps through blow-ups, which is used for the proof on the Bethe ansatz.

  13. Automatic liver segmentation on Computed Tomography using random walkers for treatment planning

    Science.gov (United States)

    Moghbel, Mehrdad; Mashohor, Syamsiah; Mahmud, Rozi; Saripan, M. Iqbal Bin

    2016-01-01

    Segmentation of the liver from Computed Tomography (CT) volumes plays an important role during the choice of treatment strategies for liver diseases. Despite lots of attention, liver segmentation remains a challenging task due to the lack of visible edges on most boundaries of the liver coupled with high variability of both intensity patterns and anatomical appearances with all these difficulties becoming more prominent in pathological livers. To achieve a more accurate segmentation, a random walker based framework is proposed that can segment contrast-enhanced livers CT images with great accuracy and speed. Based on the location of the right lung lobe, the liver dome is automatically detected thus eliminating the need for manual initialization. The computational requirements are further minimized utilizing rib-caged area segmentation, the liver is then extracted by utilizing random walker method. The proposed method was able to achieve one of the highest accuracies reported in the literature against a mixed healthy and pathological liver dataset compared to other segmentation methods with an overlap error of 4.47 % and dice similarity coefficient of 0.94 while it showed exceptional accuracy on segmenting the pathological livers with an overlap error of 5.95 % and dice similarity coefficient of 0.91. PMID:28096782

  14. Confined Random Walkers in Dimensions Higher Than One and Analysis of Transmission of Infection in Epidemics

    CERN Document Server

    Sugaya, S

    2016-01-01

    A pair of random walkers, the motion of each of which in two dimensions is confined spatially by the action of a quadratic potential centered at different locations for the two walks, are analyzed in the context of reaction-diffusion. The application sought is to the process of transmission of infection in epidemics. The walkers are animals such as rodents in considerations of the Hantavirus epidemic, infected or susceptible, the reaction is the transmission of infection, and the confining potential represents the tendency of the animals to stay in the neighborhood of their home range centers. Calculations are based on a recently developed formalism (Kenkre and Sugaya, Bull. Math. Bio. 76, 3016 (2014)) structured around analytic solutions of a Smoluchowski equation and one of its aims is the resolution of peculiar but well-known problems of reaction-diffusion theory in 2-dimensions. In the present analysis, reaction occurs not at points but in spatial regions of dimensions larger than 0. The analysis uncovers...

  15. Exact distributions of cover times for N independent random walkers in one dimension

    Science.gov (United States)

    Majumdar, Satya N.; Sabhapandit, Sanjib; Schehr, Grégory

    2016-12-01

    We study the probability density function (PDF) of the cover time tc of a finite interval of size L by N independent one-dimensional Brownian motions, each with diffusion constant D . The cover time tc is the minimum time needed such that each point of the entire interval is visited by at least one of the N walkers. We derive exact results for the full PDF of tc for arbitrary N ≥1 for both reflecting and periodic boundary conditions. The PDFs depend explicitly on N and on the boundary conditions. In the limit of large N , we show that tc approaches its average value of ≈L2/(16 D lnN ) with fluctuations vanishing as 1 /(lnN) 2 . We also compute the centered and scaled limiting distributions for large N for both boundary conditions and show that they are given by nontrivial N independent scaling functions.

  16. EVOLVE

    CERN Document Server

    Deutz, André; Schütze, Oliver; Legrand, Pierrick; Tantar, Emilia; Tantar, Alexandru-Adrian

    2017-01-01

    This book comprises nine selected works on numerical and computational methods for solving multiobjective optimization, game theory, and machine learning problems. It provides extended versions of selected papers from various fields of science such as computer science, mathematics and engineering that were presented at EVOLVE 2013 held in July 2013 at Leiden University in the Netherlands. The internationally peer-reviewed papers include original work on important topics in both theory and applications, such as the role of diversity in optimization, statistical approaches to combinatorial optimization, computational game theory, and cell mapping techniques for numerical landscape exploration. Applications focus on aspects including robustness, handling multiple objectives, and complex search spaces in engineering design and computational biology.

  17. Random walker in temporally deforming higher-order potential forces observed in a financial crisis.

    Science.gov (United States)

    Watanabe, Kota; Takayasu, Hideki; Takayasu, Misako

    2009-11-01

    Basic peculiarities of market price fluctuations are known to be well described by a recently developed random-walk model in a temporally deforming quadratic potential force whose center is given by a moving average of past price traces [M. Takayasu, T. Mizuno, and H. Takayasu, Physica A 370, 91 (2006)]. By analyzing high-frequency financial time series of exceptional events, such as bubbles and crashes, we confirm the appearance of higher-order potential force in the markets. We show statistical significance of its existence by applying the information criterion. This time series analysis is expected to be applied widely for detecting a nonstationary symptom in random phenomena.

  18. Random walker in temporally deforming higher-order potential forces observed in a financial crisis

    Science.gov (United States)

    Watanabe, Kota; Takayasu, Hideki; Takayasu, Misako

    2009-11-01

    Basic peculiarities of market price fluctuations are known to be well described by a recently developed random-walk model in a temporally deforming quadratic potential force whose center is given by a moving average of past price traces [M. Takayasu, T. Mizuno, and H. Takayasu, Physica A 370, 91 (2006)]. By analyzing high-frequency financial time series of exceptional events, such as bubbles and crashes, we confirm the appearance of higher-order potential force in the markets. We show statistical significance of its existence by applying the information criterion. This time series analysis is expected to be applied widely for detecting a nonstationary symptom in random phenomena.

  19. Analytic expression for the mean time to absorption for a random walker on the Sierpinski fractal. III. The effect of non-nearest-neighbor jumps

    Science.gov (United States)

    Balakrishnan, V.; Kozak, John J.

    2013-11-01

    We present exact, analytic results for the mean time to trapping of a random walker on the class of deterministic Sierpinski graphs embedded in d≥2 Euclidean dimensions, when both nearest-neighbor (NN) and next-nearest-neighbor (NNN) jumps are included. Mean first-passage times are shown to be modified significantly as a consequence of the fact that NNN transitions connect fractals of two consecutive generations.

  20. Analytic expression for the mean time to absorption for a random walker on the Sierpinski gasket

    Science.gov (United States)

    Kozak, John J.; Balakrishnan, V.

    2002-02-01

    The exact analytic expression for the mean time to absorption (or mean walk length) for a particle performing a random walk on a finite Sierpinski gasket with a trap at one vertex is found to be T(n)=[3n5n+1+4(5n)- 3n]/(3n+1+1) where n denotes the generation index of the gasket, and the mean is over a set of starting points of the walk distributed uniformly over all the other sites of the gasket. In terms of the number Nn of sites on the gasket and the spectral dimension d~ of the gasket, the precise asymptotic behavior for large Nn is T(n)-->1/3(2Nn)2/d~~N1.464. This serves as a partial check on our result, as it is (a) intermediate between the known results T~N2 (d=1) and T~N ln N (d=2) for random walks on d-dimensional Euclidean lattices and (b) consistent with the known result for the asymptotic behavior of the mean number of distinct sites visited in a random walk on a fractal lattice.

  1. Combined fuzzy logic and random walker algorithm for PET image tumor delineation.

    Science.gov (United States)

    Soufi, Motahare; Kamali-Asl, Alireza; Geramifar, Parham; Abdoli, Mehrsima; Rahmim, Arman

    2016-02-01

    The random walk (RW) technique serves as a powerful tool for PET tumor delineation, which typically involves significant noise and/or blurring. One challenging step is hard decision-making in pixel labeling. Fuzzy logic techniques have achieved increasing application in edge detection. We aimed to combine the advantages of fuzzy edge detection with the RW technique to improve PET tumor delineation. A fuzzy inference system was designed for tumor edge detection from RW probabilities. Three clinical PET/computed tomography datasets containing 12 liver, 13 lung, and 18 abdomen tumors were analyzed, with manual expert tumor contouring as ground truth. The standard RW and proposed combined method were compared quantitatively using the dice similarity coefficient, the Hausdorff distance, and the mean standard uptake value. The dice similarity coefficient of the proposed method versus standard RW showed significant mean improvements of 21.0±7.2, 12.3±5.8, and 18.4%±6.1% for liver, lung, and abdominal tumors, respectively, whereas the mean improvements in the Hausdorff distance were 3.6±1.4, 1.3±0.4, 1.8±0.8 mm, and the mean improvements in SUVmean error were 15.5±6.3, 11.7±8.6, and 14.1±6.8% (all P's<0.001). For all tumor sizes, the proposed method outperformed the RW algorithm. Furthermore, tumor edge analysis demonstrated further enhancement of the performance of the algorithm, relative to the RW method, with decreasing edge gradients. The proposed technique improves PET lesion delineation at different tumor sites. It depicts greater effectiveness in tumors with smaller size and/or low edge gradients, wherein most PET segmentation algorithms encounter serious challenges. Favorable execution time and accurate performance of the algorithm make it a great tool for clinical applications.

  2. Coevolution of quantum and classical strategies on evolving random networks.

    Directory of Open Access Journals (Sweden)

    Qiang Li

    Full Text Available We study the coevolution of quantum and classical strategies on weighted and directed random networks in the realm of the prisoner's dilemma game. During the evolution, agents can break and rewire their links with the aim of maximizing payoffs, and they can also adjust the weights to indicate preferences, either positive or negative, towards their neighbors. The network structure itself is thus also subject to evolution. Importantly, the directionality of links does not affect the accumulation of payoffs nor the strategy transfers, but serves only to designate the owner of each particular link and with it the right to adjust the link as needed. We show that quantum strategies outperform classical strategies, and that the critical temptation to defect at which cooperative behavior can be maintained rises, if the network structure is updated frequently. Punishing neighbors by reducing the weights of their links also plays an important role in maintaining cooperation under adverse conditions. We find that the self-organization of the initially random network structure, driven by the evolutionary competition between quantum and classical strategies, leads to the spontaneous emergence of small average path length and a large clustering coefficient.

  3. Randomly evolving idiotypic networks: modular mean field theory.

    Science.gov (United States)

    Schmidtchen, Holger; Behn, Ulrich

    2012-07-01

    We develop a modular mean field theory for a minimalistic model of the idiotypic network. The model comprises the random influx of new idiotypes and a deterministic selection. It describes the evolution of the idiotypic network towards complex modular architectures, the building principles of which are known. The nodes of the network can be classified into groups of nodes, the modules, which share statistical properties. Each node experiences only the mean influence of the groups to which it is linked. Given the size of the groups and linking between them the statistical properties such as mean occupation, mean lifetime, and mean number of occupied neighbors are calculated for a variety of patterns and compared with simulations. For a pattern which consists of pairs of occupied nodes correlations are taken into account.

  4. Dandy-Walker Malformation

    African Journals Online (AJOL)

    rme

    Dandy-Walker variant consist of vermian hypoplasia and cystic dilttion of the fourth ventricle without enlargement of the posterior fossa. (Figure 1). Fig. 1: Dandy-Walker malformation. Dandy-. Walker variant in a 13-year-old girl with thoracal scoliosis. Sagittal T1-weighted MRI shows agenesis of the corpus callosum and a.

  5. Wobbly walker evolves into soccer star

    NARCIS (Netherlands)

    Van der Linde, R.; Wisse, M.; Hobbelen, D.; De Boer, T.; Verdult, E.

    2012-01-01

    Seventeen years ago, a graduate student of the Faculty of Mechanical, Maritime and Materials Engineering built the first Delft walking robot. Not a walking computer with heavy motors, but an energy-efficient autonomous robot. That quest into human walking has developed into the Delft Biorobotics

  6. Acquiring Efficient Locomotion in a Simulated Quadruped through Evolving Random and Predefined Neural Networks

    DEFF Research Database (Denmark)

    Veenstra, Frank; Struck, Alexander; Krauledat, Matthias

    2015-01-01

    The acquisition and optimization of dynamically stable locomotion is important to engender fast and energy efficient locomotion in animals. Conventional optimization strategies tend to have difficulties in acquiring dynamically stable gaits in legged robots. In this paper, an evolving neural...... network (ENN) was implemented with the aim to optimize the locomotive behavior of a four-legged simulated robot. In the initial generation, individuals had neural networks (NNs) that were either predefined or randomly initialized. Additional investigations show that the efficiency of applying additional...... sensors to the simulated quadruped improved the performance of the ENN slightly. Promising results were seen in the evolutionary runs where the initial predefined NNs of the population contributed to slight movements of the limbs. This paper shows how a predefined ENNs linked to bio-inspired sensors can...

  7. Exploring complex networks by means of adaptive walkers

    OpenAIRE

    Prignano, Luce; Moreno, Yamir; Diaz-Guilera, Albert

    2012-01-01

    Finding efficient algorithms to explore large networks with the aim of recovering information about their structure is an open problem. Here, we investigate this challenge by proposing a model in which random walkers with previously assigned home nodes navigate through the network during a fixed amount of time. We consider that the exploration is successful if the walker gets the information gathered back home, otherwise, no data is retrieved. Consequently, at each time step, the walkers, wit...

  8. Dandy-Walker malformation

    National Research Council Canada - National Science Library

    Maria Silian Mandu Fonseca; Marta Wey Vieira; Sandra Regina Dantas Nascimento; Sandro Blasi Esposito

    2017-01-01

    Dandy-Walker malformation is characterized by complete or partial agenesis of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa with displacement...

  9. Sir Gilbert Thomas Walker

    Indian Academy of Sciences (India)

    and Iceland as 'North Atlantic Oscillation' and similar oscillation in the northern. Pacific Ocean as 'North Pacific Oscillation'. These three oscillations of surface pressure playa fundamental role in the variability of the earth's climate. Walker noted a tendency of the Southern Oscillation to persist for at least one to two seasons ...

  10. Dandy Walker malformation

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2014-10-01

    Oct 1, 2014 ... Dandy Walker Syndrome is a rare congenital malforma- tion of the central nervous system. It results ... studies have detected deletion of cerebellar genes Z1C1 and Z1C43. Incidence is 1:25,000-30,000 in ... syndrome and an emerging class of dis- eases called ciliopathies., Diagnosis is by CT scan which.

  11. Dandy Walker malformation

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2014-10-01

    Oct 1, 2014 ... Abstract: We present a rare case of Dandy Walker Syndrome in a child who presents with com- plaints of frontal headache, neck pain, fever, progressive visual impairment and multiple general- ized tonic clonic seizures, inabil- ity to stand and urinary inconti- nence. Given the clinical and neuro-imaging ...

  12. Dandy-Walker malformation

    Directory of Open Access Journals (Sweden)

    Maria Silian Mandu Fonseca

    2017-03-01

    Full Text Available Dandy-Walker malformation is characterized by complete or partial agenesis of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa with displacement of the lateral sinuses. This article aims to present current, anatomical, etiological, pathophysiological, syndromic and treatment aspects of this malformation.

  13. Exploring complex networks by means of adaptive walkers.

    Science.gov (United States)

    Prignano, Luce; Moreno, Yamir; Díaz-Guilera, Albert

    2012-12-01

    Finding efficient algorithms to explore large networks with the aim of recovering information about their structure is an open problem. Here, we investigate this challenge by proposing a model in which random walkers with previously assigned home nodes navigate through the network during a fixed amount of time. We consider that the exploration is successful if the walker gets the information gathered back home, otherwise no data are retrieved. Consequently, at each time step, the walkers, with some probability, have the choice to either go backward approaching their home or go farther away. We show that there is an optimal solution to this problem in terms of the average information retrieved and the degree of the home nodes and design an adaptive strategy based on the behavior of the random walker. Finally, we compare different strategies that emerge from the model in the context of network reconstruction. Our results could be useful for the discovery of unknown connections in large-scale networks.

  14. Perceiving Direction of a Walker: Effect of Body Appearance

    Directory of Open Access Journals (Sweden)

    Kazuya Ono

    2011-05-01

    Full Text Available Human can perceive others' walking direction accurately even with 117ms observation (Sato, et al., ECVP2008. We aimed to see whether appearance of walker's body affects the accuracy of perceiving direction of the walker. Thus, we employed three different appearances: realistic human computer-graphics body (CG-human, nonrealistic cylinder-assembled body (Cylinders, and point-light walker (Points. We made a three-dimensional model of an adult-size walker who walked at a place. CG-human stimuli were generated by rendering the model with smooth shading. We made Cylinders stimuli by replacing body parts such as arms, legs, head, and hands with cylinders. Points stimuli were made by tracking 18 positions (mostly joints of the body like biological motion. One of walkers was presented for 117, 250, 500 or 1000ms while its direction was randomly varied by 3deg steps to 21deg left or right. Observers judged whether the walker was walking toward them (hit or not (miss, and self-range was measured in terms of the standard deviation for hit distributions. The perceived self-range was narrowed with long duration, and with CG-human stimulus. It is suggested that the accuracy of perceiving walker's direction depends on body appearance, and it is higher for human-like body than nonhuman body.

  15. Lessons Learned from EVOLVE for Planning of Future Randomized Trials in Patients on Dialysis.

    Science.gov (United States)

    Parfrey, Patrick S; Block, Geoffrey A; Correa-Rotter, Ricardo; Drüeke, Tilman B; Floege, Jürgen; Herzog, Charles A; London, Gerard M; Mahaffey, Kenneth W; Moe, Sharon M; Wheeler, David C; Chertow, Glenn M

    2016-03-07

    The effect of the calcimimetic cinacalcet on cardiovascular disease in patients undergoing hemodialysis with secondary hyperparathyroidism was assessed in the Evaluation of Cinacalcet Hydrochloride Therapy to Lower Cardiovascular Events trial. This was the largest (in size) and longest (in duration) randomized controlled clinical trial undertaken in this population. During planning, execution, analysis, and reporting of the trial, many lessons were learned, including those related to the use of a composite cardiovascular primary endpoint, definition of endpoints (particularly heart failure and severe unremitting hyperparathyroidism), importance of age for optimal stratification at randomization, use of unadjusted and adjusted intention-to-treat analysis for the primary outcome, how to respond to a lower-than-predicted event rate during the trial, development of a prespecified analytic plan that accounted for nonadherence and for cointerventions that diminished the power of the trial to observe a treatment effect, determination of the credibility of a subgroup effect, use of adverse effects database to investigate rare diseases, collection of blood for biomarker measurement not designated before trial initiation, and interpretation of the benefits-to-harms ratio for individual patients. It is likely that many of these issues will arise in the planning of future trials in CKD. Copyright © 2016 by the American Society of Nephrology.

  16. Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment

    Science.gov (United States)

    Costa, Vania; Tu, Hong Anh; Wells, David; Weir, Mark; Holubowich, Corinne; Walter, Melissa

    2017-01-01

    Background Diabetic neuropathic foot ulcers are a risk factor for lower leg amputation. Many experts recommend offloading with fibreglass total contact casting, removable cast walkers, and irremovable cast walkers as a way to treat these ulcers. Methods We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for offloading devices. We performed a systematic literature search on August 17, 2016, to identify randomized controlled trials that compared fibreglass total contact casting, removable cast walkers, and irremovable cast walkers with other treatments (offloading or non-offloading) in patients with diabetic neuropathic foot ulcers. We developed a decision-analytic model to assess the cost-effectiveness of fibreglass total contact casting, removable cast walkers, and irremovable cast walkers, and we conducted a 5-year budget impact analysis. Finally, we interviewed people with diabetes who had lived experience with foot ulcers, asking them about the different offloading devices and the factors that influenced their treatment choices. Results We identified 13 randomized controlled trials. The evidence suggests that total contact casting, removable cast walkers, and irremovable cast walkers are beneficial in the treatment of neuropathic, noninfected foot ulcers in patients with diabetes but without severe peripheral arterial disease. Compared to removable cast walkers, ulcer healing was improved with total contact casting (moderate quality evidence; risk difference 0.17 [95% confidence interval 0.00–0.33]) and irremovable cast walkers (low quality evidence; risk difference 0.21 [95% confidence interval 0.01–0.40]). We found no difference in ulcer healing between total contact casting and irremovable cast walkers (low quality evidence; risk difference 0.02 [95% confidence interval −0.11–0.14]). The economic analysis showed that total contact casting and irremovable

  17. Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment.

    Science.gov (United States)

    2017-01-01

    Diabetic neuropathic foot ulcers are a risk factor for lower leg amputation. Many experts recommend offloading with fibreglass total contact casting, removable cast walkers, and irremovable cast walkers as a way to treat these ulcers. We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for offloading devices. We performed a systematic literature search on August 17, 2016, to identify randomized controlled trials that compared fibreglass total contact casting, removable cast walkers, and irremovable cast walkers with other treatments (offloading or non-offloading) in patients with diabetic neuropathic foot ulcers. We developed a decision-analytic model to assess the cost-effectiveness of fibreglass total contact casting, removable cast walkers, and irremovable cast walkers, and we conducted a 5-year budget impact analysis. Finally, we interviewed people with diabetes who had lived experience with foot ulcers, asking them about the different offloading devices and the factors that influenced their treatment choices. We identified 13 randomized controlled trials. The evidence suggests that total contact casting, removable cast walkers, and irremovable cast walkers are beneficial in the treatment of neuropathic, noninfected foot ulcers in patients with diabetes but without severe peripheral arterial disease. Compared to removable cast walkers, ulcer healing was improved with total contact casting (moderate quality evidence; risk difference 0.17 [95% confidence interval 0.00-0.33]) and irremovable cast walkers (low quality evidence; risk difference 0.21 [95% confidence interval 0.01-0.40]). We found no difference in ulcer healing between total contact casting and irremovable cast walkers (low quality evidence; risk difference 0.02 [95% confidence interval -0.11-0.14]). The economic analysis showed that total contact casting and irremovable cast walkers were less expensive and

  18. Fall prevention walker during rehabilitation

    Science.gov (United States)

    Tee, Kian Sek; E, Chun Zhi; Saim, Hashim; Zakaria, Wan Nurshazwani Wan; Khialdin, Safinaz Binti Mohd; Isa, Hazlita; Awad, M. I.; Soon, Chin Fhong

    2017-09-01

    This paper proposes on the design of a walker for the prevention of falling among elderlies or patients during rehabilitation whenever they use a walker to assist them. Fall happens due to impaired balance or gait problem. The assistive device is designed by applying stability concept and an accelerometric fall detection system is included. The accelerometric fall detection system acts as an alerting device that acquires body accelerometric data and detect fall. Recorded accelerometric data could be useful for further assessment. Structural strength of the walker was verified via iterations of simulation using finite element analysis, before being fabricated. Experiments were conducted to identify the fall patterns using accelerometric data. The design process and detection of fall pattern demonstrates the design of a walker that could support the user without fail and alerts the helper, thus salvaging the users from injuries due to fall and unattended situation.

  19. Walker-Warburg syndrome

    Directory of Open Access Journals (Sweden)

    Schachter Harry

    2006-08-01

    Full Text Available Abstract Walker-Warburg Syndrome (WWS is a rare form of autosomal recessive congenital muscular dystrophy associated with brain and eye abnormalities. WWS has a worldwide distribution. The overall incidence is unknown but a survey in North-eastern Italy has reported an incidence rate of 1.2 per 100,000 live births. It is the most severe form of congenital muscular dystrophy with most children dying before the age of three years. WWS presents at birth with generalized hypotonia, muscle weakness, developmental delay with mental retardation and occasional seizures. It is associated with type II cobblestone lissencephaly, hydrocephalus, cerebellar malformations, eye abnormalities and congenital muscular dystrophy characterized by hypoglycosylation of α-dystroglycan. Several genes have been implicated in the etiology of WWS, and others are as yet unknown. Several mutations were found in the Protein O-Mannosyltransferase 1 and 2 (POMT1 and POMT2 genes, and one mutation was found in each of the fukutin and fukutin-related protein (FKRP genes. Laboratory investigations usually show elevated creatine kinase, myopathic/dystrophic muscle pathology and altered α-dystroglycan. Antenatal diagnosis is possible in families with known mutations. Prenatal ultrasound may be helpful for diagnosis in families where the molecular defect is unknown. No specific treatment is available. Management is only supportive and preventive.

  20. Effect of everolimus on survival in advanced hepatocellular carcinoma after failure of sorafenib: the EVOLVE-1 randomized clinical trial.

    Science.gov (United States)

    Zhu, Andrew X; Kudo, Masatoshi; Assenat, Eric; Cattan, Stéphane; Kang, Yoon-Koo; Lim, Ho Yeong; Poon, Ronnie T P; Blanc, Jean-Frederic; Vogel, Arndt; Chen, Chao-Long; Dorval, Etienne; Peck-Radosavljevic, Markus; Santoro, Armando; Daniele, Bruno; Furuse, Junji; Jappe, Annette; Perraud, Kevin; Anak, Oezlem; Sellami, Dalila B; Chen, Li-Tzong

    2014-07-02

    Aside from the multikinase inhibitor sorafenib, there are no effective systemic therapies for the treatment of advanced hepatocellular carcinoma. To assess the efficacy of everolimus in patients with advanced hepatocellular carcinoma for whom sorafenib treatment failed. EVOLVE-1 was a randomized, double-blind, phase 3 study conducted among 546 adults with Barcelona Clinic Liver Cancer stage B or C hepatocellular carcinoma and Child-Pugh A liver function whose disease progressed during or after sorafenib or who were intolerant of sorafenib. Patients were enrolled from 17 countries between May 2010 and March 2012. Randomization was stratified by region (Asia vs rest of world) and macrovascular invasion (present vs absent). Everolimus, 7.5 mg/d, or matching placebo, both given in combination with best supportive care and continued until disease progression or intolerable toxicity. Per the 2:1 randomization scheme, 362 patients were randomized to the everolimus group and 184 patients to the placebo group. The primary end point was overall survival. Secondary end points included time to progression and the disease control rate (the percentage of patients with a best overall response of complete or partial response or stable disease). No significant difference in overall survival was seen between treatment groups, with 303 deaths (83.7%) in the everolimus group and 151 deaths (82.1%) in the placebo group (hazard ratio [HR], 1.05; 95% CI, 0.86-1.27; P = .68; median overall survival, 7.6 months with everolimus, 7.3 months with placebo). Median time to progression with everolimus and placebo was 3.0 months and 2.6 months, respectively (HR, 0.93; 95% CI, 0.75-1.15), and disease control rate was 56.1% and 45.1%, respectively (P = .01). The most common grade 3/4 adverse events for everolimus vs placebo were anemia (7.8% vs 3.3%, respectively), asthenia (7.8% vs 5.5%, respectively), and decreased appetite (6.1% vs 0.5%, respectively). No patients experienced hepatitis C

  1. On a random walk with memory and its relation with Markovian processes

    Energy Technology Data Exchange (ETDEWEB)

    Turban, Loic, E-mail: turban@lpm.u-nancy.f [Groupe de Physique Statistique, Departement Physique de la Matiere et des Materiaux, Institut Jean Lamour (Laboratoire associe au CNRS UMR 7198), CNRS-Nancy Universite-UPV Metz, BP 70239, F-54506 Vandoeuvre les Nancy Cedex (France)

    2010-07-16

    We study a one-dimensional random walk with memory in which the step lengths to the left and to the right evolve at each step in order to reduce the wandering of the walker. The feedback is quite efficient and leads to a non-diffusive walk. The time evolution of the displacement is given by an equivalent Markovian dynamical process. The probability density for the position of the walker is the same at any time as for a random walk with shrinking steps, although the two-time correlation functions are quite different.

  2. Intelligently Controllable Walker with Magnetorheological Fluid Brake

    Science.gov (United States)

    Kikuchi, Takehito; Tanida, Sosuke; Tanaka, Toshimasa; Kobayashi, Keigo; Mitobe, Kazuhisa

    Caster walkers are supporting frames with casters and wheels. These tools are regularly utilized as life support tools or walking rehabilitation tools in hospitals, nursing homes and individual residences. Users of the walkers can easily move it thanks to its wheels and casters. However falling accidents often happen when it moves without users. The falling accident is very serious problem and one of leading causes of secondary injuries. In the other case, it is hard to move to desired directions if users have imbalance in their motor functions or sensory functions, e.g., hemiplegic patients. To improve safeness and operability of the walkers, we installed compact MR fluid brakes on the wheels and controlled walking speed and direction of the walker. We named this intelligently controllable walker, “i-Walker” and discussed on the control methods and experimental results in this paper. Preliminary trials for direction control of the first-generation of the i-Walker (i-Walker1) are presented. On the basis of the results, we improved the control method and hardware of the i-Walker1, and developed the second-generation (i-Walker2). System description and experimental results of the i-Walker2 are also described. The i-Walker2 has better operability and lower energy consumption than that of the i-Walker1. The line-tracing controller of the i-Walker2 well controls human motions during walking experiments on the target straight line.

  3. A DNA Walker as a Fluorescence Signal Amplifier.

    Science.gov (United States)

    Wang, Dongfang; Vietz, Carolin; Schröder, Tim; Acuna, Guillermo; Lalkens, Birka; Tinnefeld, Philip

    2017-09-13

    Sensing nucleic acids typically involves the recognition of a specific sequence and reporting by, for example, a fluorogenic reaction yielding one activated dye molecule per detected nucleic acid. Here, we show that after binding to a DNA origami track a bound DNA target (a "DNA walker") can release the fluorescence of many molecules by acting as the catalyst of an enzymatic nicking reaction. As the walking kinetics sensitively depends on the walker sequence, the resulting brightness distribution of DNA origamis is a sequence fingerprint with single-nucleotide sensitivity. Using Monte Carlo simulations, we rationalize that the random self-avoiding walk is mainly terminated when steps to nearest neighbors are exhausted. Finally, we demonstrate that the DNA walker is also active in a plasmonic hotspot for fluorescence enhancement, indicating the potential of combining different amplification mechanisms enabled by the modularity of DNA nanotechnology.

  4. Evolving virtual creatures and catapults.

    Science.gov (United States)

    Chaumont, Nicolas; Egli, Richard; Adami, Christoph

    2007-01-01

    We present a system that can evolve the morphology and the controller of virtual walking and block-throwing creatures (catapults) using a genetic algorithm. The system is based on Sims' work, implemented as a flexible platform with an off-the-shelf dynamics engine. Experiments aimed at evolving Sims-type walkers resulted in the emergence of various realistic gaits while using fairly simple objective functions. Due to the flexibility of the system, drastically different morphologies and functions evolved with only minor modifications to the system and objective function. For example, various throwing techniques evolved when selecting for catapults that propel a block as far as possible. Among the strategies and morphologies evolved, we find the drop-kick strategy, as well as the systematic invention of the principle behind the wheel, when allowing mutations to the projectile.

  5. 21 CFR 890.3825 - Mechanical walker.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mechanical walker. 890.3825 Section 890.3825 Food... DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3825 Mechanical walker. (a) Identification. A mechanical walker is a four-legged device with a metal frame intended for medical purposes to...

  6. The escape problem for mortal walkers

    CERN Document Server

    Grebenkov, D S

    2016-01-01

    We introduce and investigate the escape problem for random walkers that may eventually die, decay, bleach, or lose activity during their diffusion towards an escape or reactive region on the boundary of a confining domain. In the case of a first-order kinetics (i.e., exponentially distributed lifetimes), we study the effect of the associated death rate onto the survival probability, the exit probability, and the mean first passage time. We derive the upper and lower bounds and some approximations for these quantities. We reveal three asymptotic regimes of small, intermediate and large death rates. General estimates and asymptotics are compared to several explicit solutions for simple domains, and to numerical simulations. These results allow one to account for stochastic photobleaching of fluorescent tracers in bio-imaging, degradation of mRNA molecules in genetic translation mechanisms, or high mortality rates of spermatozoa in the fertilization process. This is also a mathematical ground for optimizing stor...

  7. Value of first day angiography/angioplasty in evolving Non-ST segment elevation myocardial infarction: an open multicenter randomized trial. The VINO Study.

    Science.gov (United States)

    Spacek, R; Widimský, P; Straka, Z; Jiresová, E; Dvorák, J; Polásek, R; Karel, I; Jirmár, R; Lisa, L; Budesínský, T; Málek, F; Stanka, P

    2002-02-01

    Direct angioplasty is an effective treatment for ST-elevation myocardial infarction. The role of very early angioplasty in non-ST-elevation infarction is not known. Thus, a randomized study of first day angiography/angioplasty vs early conservative therapy of evolving myocardial infarction without persistent ST-elevation was conducted. One hundred and thirty-one patients with confirmed acute myocardial infarction without ST-segment elevations were randomized within 24 h of last rest chest pain: 64 in the first day angiography/angioplasty group and 67 in the early conservative group (coronary angiography only after recurrent or stress induced myocardial ischaemia). All patients in the invasive group underwent coronary angiography on the day of admission (mean randomization-angiography time 6.2 h). First day angioplasty of the infarct related artery was performed in 47% of the patients and bypass surgery in 35%. In the conservative group, 55% underwent coronary angiography, 10% angioplasty and 30% bypass surgery within 6 months. The primary end-point (death/reinfarction) at 6 months occurred in 6.2% vs 22.3% (P<0.001). Six month mortality in the first day angiography/angioplasty group was 3.1% vs 13.4% in the conservative group (P<0.03). Non-fatal reinfarction occurred in 3.1% vs. 14.9% (P<0.02). First day coronary angiography followed by angioplasty whenever possible reduces mortality and reinfarction in evolving myocardial infarction without persistent ST-elevation, in comparison with an early conservative treatment strategy. Copyright 2001 The European Society of Cardiology.

  8. COMPUTER ANALYSIS OF ELECTROMOTORIC SWIVEL WALKER MOVEMENT

    Directory of Open Access Journals (Sweden)

    Jozef VARGA

    2016-12-01

    Full Text Available The first mechanical construction of swivel walker is from year 1963 and it was aimed for support movement of people with disabilities. This solution was very difficult and it was main reason for purpose of electromotoric module, which facilitates movement and reduce effort of people with disabilities. Therefore further research in this area are still provided. In this paper trajectory of swivel walker with electromotoric modules is described. To analyze the tilt and trajectory structure of the walker SolidWorks software was implemented.

  9. CommWalker: Correctly Evaluating Modules in Molecular Networks in Light of Annotation Bias.

    Science.gov (United States)

    Luecken, M D; Page, M J T; Crosby, A J; Mason, S; Reinert, G; Deane, C M

    2017-11-03

    Detecting novel functional modules in molecular networks is an important step in biological research. In the absence of gold standard functional modules, functional annotations are often used to verify whether detected modules/communities have biological meaning. However, as we show, the uneven distribution of functional annotations means that such evaluation methods favour communities of well-studied proteins. We propose a novel framework for the evaluation of communities as functional modules. Our proposed framework, CommWalker, takes communities as inputs and evaluates them in their local network environment by performing short random walks. We test CommWalker's ability to overcome annotation bias using input communities from four community detection methods on two protein interaction networks. We find that modules accepted by CommWalker are similarly co-expressed as those accepted by current methods. Crucially, CommWalker performs well not only in well-annotated regions, but also in regions otherwise obscured by poor annotation. CommWalker community prioritization both faithfully captures well-validated communities, and identifies functional modules that may correspond to more novel biology. The CommWalker algorithm is freely available at opig.stats.ox.ac.uk/resources or as a docker image on the Docker Hub at hub.docker.com/r/lueckenmd/commwalker/. deane@stats.ox.ac.uk. Supplementary data are available at Bioinformatics online.

  10. The escape problem for mortal walkers

    Science.gov (United States)

    Grebenkov, D. S.; Rupprecht, J.-F.

    2017-02-01

    We introduce and investigate the escape problem for random walkers that may eventually die, decay, bleach, or lose activity during their diffusion towards an escape or reactive region on the boundary of a confining domain. In the case of a first-order kinetics (i.e., exponentially distributed lifetimes), we study the effect of the associated death rate onto the survival probability, the exit probability, and the mean first passage time. We derive the upper and lower bounds and some approximations for these quantities. We reveal three asymptotic regimes of small, intermediate, and large death rates. General estimates and asymptotics are compared to several explicit solutions for simple domains and to numerical simulations. These results allow one to account for stochastic photobleaching of fluorescent tracers in bio-imaging, degradation of mRNA molecules in genetic translation mechanisms, or high mortality rates of spermatozoa in the fertilization process. Our findings provide a mathematical ground for optimizing storage containers and materials to reduce the risk of leakage of dangerous chemicals or nuclear wastes.

  11. Genetics Home Reference: Dandy-Walker malformation

    Science.gov (United States)

    ... Walker malformation , signs and symptoms caused by abnormal brain development are present at birth or develop within the first year of life. Some children have a buildup of fluid in the brain ( ...

  12. Anatomic variants in Dandy-Walker complex.

    Science.gov (United States)

    Jurcă, Maria Claudia; Kozma, Kinga; Petcheşi, CodruŢa Diana; Bembea, Marius; Pop, Ovidiu Laurean; MuŢiu, Gabriela; Coroi, Mihaela Cristiana; Jurcă, Alexandru Daniel; Dobjanschi, Luciana

    2017-01-01

    Dandy-Walker complex (DWC) is a malformative association of the central nervous system. DWC includes four different types: Dandy-Walker malformation (vermis agenesis or hypoplasia, cystic dilatation of the fourth ventricle and a large posterior fossa); Dandy-Walker variant (vermis hypoplasia, cystic dilatation of the fourth ventricle, normal posterior fossa); mega cysterna magna (large posterior fossa, normal vermis and fourth ventricle) and posterior fossa arachnoid cyst. We present and discuss four cases with different morphological and clinical forms of the Dandy-Walker complex. In all four cases, diagnosis was reached by incorporation of clinical (macrocephaly, seizures) and imaging [X-ray, computed tomography (CT), magnetic resonance imaging (MRI)] data. Two patients were diagnosed with Dandy-Walker complex, one patient was diagnosed with Dandy-Walker variant in a rare association with neurofibromatosis and one patient was diagnosed with a posterior fossa arachnoid cyst associated with left-sided Claude Bernard-Horner syndrome, congenital heart disease (coarctation of the aorta, mitral stenosis) and gastroesophageal reflux. In all forms of DWC, the clinical, radiological and functional manifestations are variable and require adequate diagnostic and therapeutic measures.

  13. [Dandy-Walker complex: a clinicopathologic study of 9 cases].

    Science.gov (United States)

    Zhang, Xiao-bo; Gu, Yi-qun; Sun, Xiao-fei; Wang, Ying-nan; Wang, Ai-chun

    2013-12-01

    To investigate the etiology, pathogenesis, clinicopathologic characteristics, clinical prognosis and treatment of Dandy-Walker syndrome. Nine cases of Dandy-Walker syndrome were included in the study. The autopsy findings and clinical history were evaluated along with review of the literature. The causes, pathogenetic mechanism, pathologic features and prognosis of Dandy-Walker syndrome were analyzed. Among 9 Dandy-Walker syndrome cases, six patients presented with variants of Dandy-Walker complex and 3 cases had classic Dandy-Walker malformation. In addition, 4 patients presented with combined lateral ventricle expansion and multiple malformations were seen in 7 cases. Combined umbilical cord abnormality was noted in 4 patients with variant of Dandy-Walker complex and combined placental abnormality was seen in one classic Dandy-Walker syndrome. Dandy-Walker syndrome is a rare disease. In addition to complex pathogenesis with possible genetic and environmental antigenic etiologies, placental and umbilical cord abnormality may be also related to its development.

  14. Emerging trends in evolving networks: Recent behaviour dominant and non-dominant model

    Science.gov (United States)

    Abbas, Khushnood; Shang, Mingsheng; Luo, Xin; Abbasi, Alireza

    2017-10-01

    Novel phenomenon receives similar attention as popular one. Therefore predicting novelty is as important as popularity. Emergence is the side effect of competition and ageing in evolving systems. Recent behaviour or recent link gain in networks plays an important role in emergence. We exploited this wisdom and came up with two models considering different scenarios and systems. Where recent behaviour dominates over total behaviour (total link gain) in the first one, and recent behaviour is as important as total behaviour for future link gain in the second one. It supposes that random walker walks on a network and can jump to any node, the probability of jumping or making a connection to other node is based on which node is recently more active or receiving more links. In our assumption, the random walker can also jump to the node which is already popular but recently not popular. We are able to predict emerging nodes which are generally suppressed under preferential attachment effect. To show the performance of our model we have conducted experiments on four real data sets namely, MovieLens, Netflix, Facebook and Arxiv High Energy Physics paper citation. For testing our model we used four information retrieval indices namely Precision, Novelty, Area Under Receiving Operating Characteristic (AUC) and Kendal's rank correlation coefficient. We have used four benchmark models for validating our proposed models. Although our model does not perform better in all the cases but, it has theoretical significance in working better for recent behaviour dominated systems.

  15. (N+1)-dimensional Lorentzian evolving wormholes supported by polytropic matter

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Mauricio [Universidad del Bio-Bio, Departamento de Fisica, Facultad de Ciencias, Concepcion (Chile); Arostica, Fernanda; Bahamonde, Sebastian [Universidad de Concepcion, Departamento de Fisica, Concepcion (Chile)

    2013-08-15

    In this paper we study (N+1)-dimensional evolving wormholes supported by energy satisfying a polytropic equation of state. The considered evolving wormhole models are described by a constant redshift function and generalizes the standard flat Friedmann-Robertson-Walker spacetime. The polytropic equation of state allows us to consider in (3+1)-dimensions generalizations of the phantom energy and the generalized Chaplygin gas sources. (orig.)

  16. Maintaining evolvability.

    Science.gov (United States)

    Crow, James F

    2008-12-01

    Although molecular methods, such as QTL mapping, have revealed a number of loci with large effects, it is still likely that the bulk of quantitative variability is due to multiple factors, each with small effect. Typically, these have a large additive component. Conventional wisdom argues that selection, natural or artificial, uses up additive variance and thus depletes its supply. Over time, the variance should be reduced, and at equilibrium be near zero. This is especially expected for fitness and traits highly correlated with it. Yet, populations typically have a great deal of additive variance, and do not seem to run out of genetic variability even after many generations of directional selection. Long-term selection experiments show that populations continue to retain seemingly undiminished additive variance despite large changes in the mean value. I propose that there are several reasons for this. (i) The environment is continually changing so that what was formerly most fit no longer is. (ii) There is an input of genetic variance from mutation, and sometimes from migration. (iii) As intermediate-frequency alleles increase in frequency towards one, producing less variance (as p --> 1, p(1 - p) --> 0), others that were originally near zero become more common and increase the variance. Thus, a roughly constant variance is maintained. (iv) There is always selection for fitness and for characters closely related to it. To the extent that the trait is heritable, later generations inherit a disproportionate number of genes acting additively on the trait, thus increasing genetic variance. For these reasons a selected population retains its ability to evolve. Of course, genes with large effect are also important. Conspicuous examples are the small number of loci that changed teosinte to maize, and major phylogenetic changes in the animal kingdom. The relative importance of these along with duplications, chromosome rearrangements, horizontal transmission and polyploidy

  17. Fermi-Walker transport and Thomas precession

    Science.gov (United States)

    Pastor Lambare, Justo

    2017-07-01

    An exact derivation of the Thomas precession formula is presented based on the Fermi-Walker transport equation. Given that the Thomas precession effect is not a particularly intuitive phenomenon, such that when discovered in 1925 it took by surprise even experts in relativity theory, Einstein included, an alternative perspective can be useful at an intermediate level for physics students. The existing literature linking the Thomas precession to Fermi-Walker transport use geometric algebra as mathematical tool. Here the mathematics is kept within the limits of the usual vector and tensor algebra commonly used in special relativity theory at a level appropriate for advanced undergraduate and beginning graduate students.

  18. Two cases of Dandy-Walker syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Chul Koo; Chang, Kee Hyun [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1982-06-15

    Two cases of Dandy- Walker syndrome are reported with emphasis on CT findings. The Dandy-Walker syndrome is known to be a developmental anomaly, which is a congenital cystic dilatation of the fourth ventricle due to atresia of foramen Magendie and possibly also foramen Luschka, associated with some form of vermian dysgenesis. The CT finding of one cases reveal huge cystic mass in midline of the posterior cranial fossa with small compressed cerebellar hemisphere in the lateral portion, associated with hydrocephalus. The other shows semilunar-shaped cystic mass in posterior cranial fossa with anteriorly displaced cerebellum, which communicates with apparent fourth ventricle through the vallecula. Both cases show no inferior.

  19. Digital elevation model of Walker Lake, West-Central Nevada

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Accurately determining the bathymetry and...

  20. Dandy Walker malformation (variant): late presentation with ...

    African Journals Online (AJOL)

    We present a rare case of Dandy Walker Syndrome in a child who presents with complaints of frontal headache, neck pain, fever, progressive visual impairment and multiple generalized tonic clonic seizures, inability to stand and urinary incontinence. Given the clinical and neuro-imaging findings, the diagnosis of Dandy ...

  1. Síndrome de Dandy-walker

    Directory of Open Access Journals (Sweden)

    Jaderson Costa da Costa

    1973-03-01

    Full Text Available São relatados os casos de 4 pacientes com síndrome de Dandy-Walker diagnosticada pela pneumencefalografia fracionada e ventriculografia. O tratamento e a patogenia desta malformação são discutidos com base em dados embriológicos.

  2. Psychiatric misdiagnoses in Dandy-Walker variant.

    Science.gov (United States)

    Blaettner, C; Pfaffenberger, N M; Cartes-Zumelzu, F; Hofer, A

    2015-01-01

    Cases of intellectual impairment and aberrant behavior in patients with cerebellar diseases have been described since the early nineteenth century. Here, we report on a patient suffering from Dandy-Walker variant who presented with symptoms of obsessive compulsive disorder and delusional disorder. The current findings emphasize the potential relevance of focal cerebellar lesions as organic correlates of these disorders.

  3. Three Cases of Walker Warburg Syndrome

    Directory of Open Access Journals (Sweden)

    Adnan Ayvaz

    2013-10-01

    Full Text Available    Walker-Warburg syndrome (WWS, a rare form of congenital muscular dystrophy, is an autosomal recessive disorder affecting the brain, eye, and muscles. In this study, three WWS cases followed in the pediatric clinic of Cumhuriyet University are presented. According to our knowledge, one of our patients is the longestlived case who has been reported.

  4. Obituary: Robert Mowbray Walker, 1929-2004

    Science.gov (United States)

    Schoenherr, Neil T.

    2004-12-01

    Robert M. Walker, PhD, Professor of Physics in Arts & Sciences and a faculty fellow of the McDonnell Center for the Space Sciences, died of stomach cancer Thursday, 12 February 2004, in Brussels, Belgium. He was 75. Walker worked on the frontiers of space research for more than four decades. Robert Walker was born in Philadelphia on 6 February 1929. His mother was Dorothy Potter and he considered Roger Potter his father though he was not his biological father. His early years were spent in New York City and in upstate New York. He attended the Bronx High School of Science, earned his BS in physics from Union College and in 1954, he received his PhD in particle physics from Yale University. He subsequently joined the General Electric Laboratory in Schenectady, New York where he studied the radiation effects in solids. His work on defects in irradiated copper is still regarded as the definitive work on the topic. In the early 1960s, Walker's discovery of fossil nuclear particle tracks in minerals was instrumental to new developments in geo-chronology and cosmic ray physics. In particular, his discovery of tracks from nuclei heavier than iron opened a new frontier of cosmic ray physics. He subsequently pioneered the use of plastics to detect and count such nuclei in cosmic ray balloon flights. Beginning in 1966, when he moved to Washington University and became the first McDonnell Professor of Physics, his research interests turned more toward space physics. He was the inaugural director of the McDonnell Center, which was established in 1975 by a gift from aerospace pioneer James S. McDonnell. Walker was a member of the NASA committee that allocated samples of the first returned lunar materials, and his laboratory led the way in deciphering their record of lunar, solar system and galactic evolution. Together with Ghislaine Crozaz and other colleagues, Walker made path breaking laboratory studies of the first moon rocks revealing the history of solar radiation and

  5. Space Walker - the Cognitive Visualization System

    Science.gov (United States)

    Komarinskiy, S.; Vitkovskiy, V. V.; Gorohov, V.; Zakharevski, D.

    2008-08-01

    The data cognitive visualization system --- ``Space Walker'' is presented. The creation of program products requires the practical mastery of the entire complex of achievements in the field of mathematical statistics, theory of illegible sets, cognitive machine drawing, cognitive psychology and theory of knowledge. SW system base on the ground of possibility use already acting program software intellectual support adopted solution in task control complex system with deep a priori uncertainty.

  6. Dandy–Walker malformation: An incidental finding

    Science.gov (United States)

    Tadakamadla, Jyothi; Kumar, Santhosh; Mamatha, G. P.

    2010-01-01

    Dandy–Walker malformation (DWM) is a rare intracranial congenital abnormality that affects the cerebellum and some of its components; particularly cerebellar vermis, fourth ventricle and is characterized by an enlarged posterior fossa. Although there is an extensive list of signs attributed to DWM, final diagnosis is solely dependent on imaging techniques as there are no signs that are characteristic of DWM. This article reports a case with DWM who was diagnosed by magnetic resonance imaging. PMID:20838490

  7. Hydrocephalus in Dandy-Walker malformation.

    Science.gov (United States)

    Spennato, Pietro; Mirone, Giuseppe; Nastro, Anna; Buonocore, Maria Consiglio; Ruggiero, Claudio; Trischitta, Vincenzo; Aliberti, Ferdinando; Cinalli, Giuseppe

    2011-10-01

    Even if the first description of Dandy-Walker dates back 1887, difficulty in the establishment of correct diagnosis, especially concerning differential diagnosis with other types of posterior fossa CSF collection, still persists. Further confusion is added by the inclusion, in some classification, of different malformations with different prognosis and therapeutic strategy under the same label of "Dandy-Walker". An extensive literature review concerning embryologic, etiologic, pathogenetic, clinical and neuroradiological aspects has been performed. Therapeutic options, prognosis and intellectual outcome are also reviewed. The correct interpretation of the modern neuroradiologic techniques, including CSF flow MR imaging, may help in identifying a "real" Dandy-Walker malformation. Among therapeutical strategies, single shunting (ventriculo-peritoneal or cyst-peritoneal shunts) appears effective in the control of both ventricle and cyst size. Endoscopic third ventriculostomy may be considered an acceptable alternative, especially in older children, with the aim to reduce the shunt-related problems. Prognosis and intellectual outcome mostly depend on the presence of associated malformations, the degree of vermian malformation and the adequate control of hydrocephalus.

  8. [Dandy-Walker variant: Case report].

    Science.gov (United States)

    Cueva-Núñez, José E; Lozano-Bustillo, Alejandra; Irias-Álvarez, Merlyn S; Vásquez-Montes, Raúl F; Varela-González, Douglas M

    Dandy Walker variant is defined by a variable hypoplasia of the cerebellar vermix with or without posterior fossa increase and without tentorium elevation. describe the case of a rare disease and emphasise the need to clarify the aetiology of prenatal malformations, as well as its multidisciplinary management. A male patient, 8 years of age, with a history of Infantile Cerebral Palsy and epilepsy, who was admitted with a history of tonic-clonic seizures. He was admitted due to psycho-motor developmental delay. During his hospitalisation, he had multiple seizure episodes, controlled with anticonvulsants. A computerized tomography was performed, in which communication was observed between the cisterna magna and fourth ventricle (the latter increased in size). In addition, the cerebellar vermix showed a partial hypoplasia. All these findings were compatible with a variant of the Dandy Walker syndrome. Dandy Walker variant may be asymptomatic and the images found may not indicate them as the cause of developmental disorders, due to its association with multiple syndromes and chromosomal abnormalities. Clinical presentation and prognosis depends on the related disorders, and a multidisciplinary approach is important, because the treatment depends on the symptoms presented. Copyright © 2016 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Auditory perception of a human walker.

    Science.gov (United States)

    Cottrell, David; Campbell, Megan E J

    2014-01-01

    When one hears footsteps in the hall, one is able to instantly recognise it as a person: this is an everyday example of auditory biological motion perception. Despite the familiarity of this experience, research into this phenomenon is in its infancy compared with visual biological motion perception. Here, two experiments explored sensitivity to, and recognition of, auditory stimuli of biological and nonbiological origin. We hypothesised that the cadence of a walker gives rise to a temporal pattern of impact sounds that facilitates the recognition of human motion from auditory stimuli alone. First a series of detection tasks compared sensitivity with three carefully matched impact sounds: footsteps, a ball bouncing, and drumbeats. Unexpectedly, participants were no more sensitive to footsteps than to impact sounds of nonbiological origin. In the second experiment participants made discriminations between pairs of the same stimuli, in a series of recognition tasks in which the temporal pattern of impact sounds was manipulated to be either that of a walker or the pattern more typical of the source event (a ball bouncing or a drumbeat). Under these conditions, there was evidence that both temporal and nontemporal cues were important in recognising theses stimuli. It is proposed that the interval between footsteps, which reflects a walker's cadence, is a cue for the recognition of the sounds of a human walking.

  10. [Differential diagnosis of Dandy-Walker syndrome different presentations].

    Science.gov (United States)

    Tobías-González, Pablo; Gil Mira, Mar; Valero de Bernabé, Javier; Zapardiel, Ignacio

    2012-08-01

    Dandy-Walker syndrome is a set of abnormalities of the posterior fossa including three modalities: classic Dandy-Walker malformation, Dandy-Walker variant and mega-cisterna magna. Our objective is clarify the differential diagnosis among these entities. Descriptive and retrospective study of Dandy-Walker cases diagnosed at our Department during the last five years plus a review of the related Medical literature. Three cases of Dandy-Walker modalities are reported: one case of classic Dandy-Walker malformation, one case of Dandy-Walker variant, and one case of false Dandy-Walker. In the first two cases the patients underwent legal abortion, whereas in the last one a healthy male newborn was delivered in the week 38 of gestation. Malformations in the posterior fossa, including Dandy-Walker syndrome, are still a challenge in prenatal diagnosis. Technical developments in imaging, such as in three-dimensional sonography and magnetic resonance, allow higher resolution and multiplanar images for an easier diagnose. There is a high rate of false positive, particularly before the 18th week of gestation. It is advisable not to establish a final diagnose before that week.

  11. DNA Walker-Regulated Cancer Cell Growth Inhibition.

    Science.gov (United States)

    Li, Feiran; Cha, Tae-Gon; Pan, Jing; Ozcelikkale, Altug; Han, Bumsoo; Choi, Jong Hyun

    2016-06-16

    We demonstrate a DNAzyme-based walker system as a controlled oligonucleotide drug AS1411 release platform for breast cancer treatment. In this system, AS1411 strands are released from fuel strands as a walker moves along its carbon nanotube track. The release rate and amount of anticancer oligonucleotides are controlled by the walker operation. With a walker system embedded within the collagen extracellular matrix, we show that this drug release system can be used for in situ cancer cell growth inhibition. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Chinese species of Pediobius Walker (Hymenoptera: Eulophidae).

    Science.gov (United States)

    Cao, Huan-Xi; Salle, John LA; Zhu, Chao-Dong

    2017-03-08

    The Chinese species of Pediobius Walker, 1846 are treated in this paper, resulting in 34 species, of which 5 are newly described: P. bisulcatus Cao & Zhu sp. n., P. elongatus Cao & Zhu sp. n., P.petiolapilus Cao & Zhu sp. n., P. prominentis Cao & Zhu, sp. n., and P. tortricida Cao & Zhu, sp. n. Nine species are also newly recorded from China: P. anomalus (Gahan, 1920), P. bethylicidus Kerrich, 1973, P. bruchicida (Rondani, 1872), P. cassidae Erdös, 1958, P. claviger (Thomson, 1878), P. erionotae Kerrich, 1973, P. phragmitis Bouček, 1965, P. saulius (Walker, 1839), and P. tetratomus (Thomson, 1878). Four new synonyms are proposed: P. illiberidis Liao, 1987 under P. pyrgo (Walker, 1839) syn. n., P. planiceps Sheng & Kamijo, 1992 under P. inexpectatus Kerrich, 1973 syn. n., P. sinensis Sheng & Wang, 1994 under P. facialis (Giraud, 1863) syn. n., and P. songshaominus Liao, 1987 under P. yunanensis Liao, 1987 syn. n. The species-group concept is used to compare similar species, of which eight are recognized in China including two newly recognized groups: the cassidae-group and the crassicornis-group. One species complex, the P. eubius complex, is also recognized. An updated checklist of the Chinese species of Pediobius is provided, with species-group placement. New host records for Pediobius species from China are summarized in a table and valid species possibly present in China but not included in this study in another table. A key to all known females and males of Chinese Pediobius is also provided.

  13. [Physical risks whilst walking the Nijmegen Four Days Marches in 2007: electrolyte imbalance in 1 in 5 walkers

    NARCIS (Netherlands)

    Eijsvogels, T.M.H.; Thijssen, D.H.J.; Poelkens, F.; Binkhorst, M.; Wouters, C.W.; Schouwenberg, B.J.J.W.; Hopman, M.T.E.

    2008-01-01

    OBJECTIVE: To determine the physiological impact and health risks for walkers during the Nijmegen (the Netherlands) Four Days Marches in 2007, the largest walking event in the world with more than 45,000 participants. DESIGN: Observational study. METHODS: 66 volunteers were randomly selected and

  14. GPS constraints on shear accommodation in the northern Walker Lane, western Nevada, USA

    Science.gov (United States)

    Bormann, J. M.; Hammond, W. C.; Kreemer, C. W.; Blewitt, G.; Wesnousky, S. G.

    2009-12-01

    The Walker Lane is a zone of active intracontinental transtension that accommodates approximately 10 mm/yr of right-lateral deformation, up to 20-25% of Pacific-North America relative plate motion. Between Walker Lake and Lake Tahoe, the Walker Lane lacks optimally oriented strike-slip faults to accommodate northwest-directed dextral shear. In this region Quaternary deformation appears to be concentrated in a northwest-trending series of north-striking, normal fault-bounded basins. To address the question of how shear is transferred through this portion of the Walker Lane, we combine GPS data from the University of Nevada, Reno’s semi-continuous MAGNET GPS network with observations from EarthScope’s Plate Boundary Observatory to present a new velocity field for the Walker Lane with an average station spacing of 20 km. Measurements in MAGNET (http://geodesy.unr.edu/networks) began in January 2004 and now provide time series of up to 6 years for the longest running sites and >3 years for all sites. Together with recent improvements in GPS data processing models using the GIPSY-OASIS II software, this allows us to estimate rates with uncertainty well below 1 mm/yr. These recent improvements include the use of reprocessed GPS orbits from the IGS Analysis Center at JPL. Our GPS processing now includes satellite and station antenna calibrations, random-walk tropospheric zenith delay and gradients using the GMF mapping function, second-order ionospheric corrections, global-scale ambiguity resolution using our custom Ambizap software, and our custom Great Basin spatially-filtered reference frame. The velocity solution shows a smooth and continuous increase in shear across the Walker Lane in addition to NW-SE directed extension. We use a block model driven by GPS velocities to estimate the role that vertical axis rotation of fault-bounded blocks and slip on basin-bounding faults play in shear accommodation. The block model also allows us to incorporate published

  15. Variante de Dandy Walker: relato de caso = Dandy Walker variant: a case report

    Directory of Open Access Journals (Sweden)

    Khan, Richard Lester et al.

    2009-01-01

    Full Text Available Objetivos: relatar o caso de um paciente com variante de Dandy Walker, chamando atenção para a importância da suspeita, investigação e manejo das repercussões clínicas. Descrição do caso: é relatado o caso de um paciente do sexo masculino, com quadro clínico e radiológico típico da Variante de Dandy Walker. Durante o pré-natal, através de ecografia obstétrica com 23 semanas e 3 dias, apresentou alterações sugestivas de Síndrome de Dandy Walker. Ao nascimento apresentou exame físico com fenda palatina, criptorquidia à direita, hexodactilia em ambos os pés. Apresentava ainda ecocardiograma com forame oval patente e persistência do canal arterial. O diagnóstico foi estabelecido através da ressonância magnética realizada após o nascimento, que evidenciava hipoplasia do vermis cerebelar, alargamento da fossa posterior e leve dilatação ventricular. Conclusões: este artigo procura caracterizar a variante de Dandy Walker, que é uma malformação congênita do sistema nervoso central e é o tipo mais comum da Síndrome de Dandy Walker. Seu fenótipo é variável, devendo-se sempre pesquisar malformações tanto intra quanto extracranianas, visto que o risco de mortalidade pós-natal aumenta quando existe esta associação. O tratamento envolve equipe multidisciplinar e o prognóstico é reservado, variando conforme o fenótipo.

  16. Case Report: Trigonocephaly and Dandy walker variant in an ...

    African Journals Online (AJOL)

    ... with Opitz trigonocephaly C syndrome (OTCS). We consider our patient as a mild form of OTCS and he needs close follow up because over time there may be a developmental delay, severe mental retardation and seizures. Keywords: Dandy walker malformation – Dandy walker variant; Craniosynostosis; Trigonocephaly ...

  17. Non-linear continuous time random walk models★

    Science.gov (United States)

    Stage, Helena; Fedotov, Sergei

    2017-11-01

    A standard assumption of continuous time random walk (CTRW) processes is that there are no interactions between the random walkers, such that we obtain the celebrated linear fractional equation either for the probability density function of the walker at a certain position and time, or the mean number of walkers. The question arises how one can extend this equation to the non-linear case, where the random walkers interact. The aim of this work is to take into account this interaction under a mean-field approximation where the statistical properties of the random walker depend on the mean number of walkers. The implementation of these non-linear effects within the CTRW integral equations or fractional equations poses difficulties, leading to the alternative methodology we present in this work. We are concerned with non-linear effects which may either inhibit anomalous effects or induce them where they otherwise would not arise. Inhibition of these effects corresponds to a decrease in the waiting times of the random walkers, be this due to overcrowding, competition between walkers or an inherent carrying capacity of the system. Conversely, induced anomalous effects present longer waiting times and are consistent with symbiotic, collaborative or social walkers, or indirect pinpointing of favourable regions by their attractiveness. Contribution to the Topical Issue "Continuous Time Random Walk Still Trendy: Fifty-year History, Current State and Outlook", edited by Ryszard Kutner and Jaume Masoliver.

  18. Evolvable synthetic neural system

    Science.gov (United States)

    Curtis, Steven A. (Inventor)

    2009-01-01

    An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

  19. Speed and exercise intensity of recreational walkers.

    Science.gov (United States)

    Murtagh, Elaine M; Boreham, Colin A G; Murphy, Marie H

    2002-10-01

    Brisk walking has been identified as an activity suited to meet American College of Sport Medicine/Centers for Disease Control and Prevention recommendations for moderate intensity exercise (55-69% HR(max), 40-59% VO(2)R). However, little is known about whether recreational walkers self-select a pace which elicits this intensity and how they interpret the term "brisk walking." The walking speed of 82 adults was covertly observed in a public park. Fifty-nine of these participants demonstrated their interpretation of "brisk walking" and the speed was noted. Eleven of these subjects subsequently walked on a treadmill at their observed and "brisk walk" speeds. Heart rate (HR), respiratory gases, and ratings of perceived exertion (RPE) were measured. Mean observed and "brisk" walking speeds were 1.56 +/- 0.17 m. s(-1) and 1.79 +/- 0.19 m x s(-1) respectively (P exercise intensities during the treadmill test (n = 11) were 59.0 +/- 13.4% VO(2max) and 67.3 +/- 11.6% HR(max) for the observed speed (1.60 + 0.24 m x s(-1)). The brisk speed (1.86 +/- 0.12 m x s(-1)) equated to 68.6 +/- 14.9% VO(2max) and 78.5 +/- 15.5% HR(max). The speed and intensity selected by this group of walkers meets current recommendations for moderate intensity exercise. Instructing individuals to "walk briskly" prompts more vigorous activity. Copyright 2002 American Health Foundation and Elsevier Science (USA)

  20. Síndrome de Dandy-walker The Dandy-Walker syndrome. Report of four cases

    Directory of Open Access Journals (Sweden)

    Jaderson Costa da Costa

    1973-03-01

    Full Text Available São relatados os casos de 4 pacientes com síndrome de Dandy-Walker diagnosticada pela pneumencefalografia fracionada e ventriculografia. O tratamento e a patogenia desta malformação são discutidos com base em dados embriológicos.Four cases of Dandy-Walker syndrome diagnosed through encephalography and ventriculography with air are reported. The pathogenesis of this malformation is discussed. Particularly stressed are the radiological aspects of the condition, which are considered to be pathognomonic. The roentgenological findings are quite typical, indicating the extreme dolichocephaly, thinning and bulging of the bones of the posterior cranial fossa, prominent separation of the lambdoid sutures and an abnormal position of the lateral sinuses. Ventriculography shows symmetric hydrocephalus with extremely large cyst -like formation in the posterior fossa. Surgical indications are also considered. The ventricle lateral shunt is the recommended treatment for the DandyWalker malformations which show cerebral subarachnoid agenesis by pneumoencephalography.

  1. Myopic random walkers and exclusion processes: Single and multispecies

    Science.gov (United States)

    Landman, Kerry A.; Fernando, Anthony E.

    2011-10-01

    A motility mechanism based on a simple exclusion process, where the probability of movement of an agent depends on the number of unoccupied nearest-neighbor sites is considered. Such interacting agents are termed myopic. This problem is an extension of the famous blind or myopic ant in a labyrinth problem. For the interacting agent models considered here, each agent plays the role of an ant in a labyrinth, where the paths of allowed sites though the labyrinth consist of sites not occupied by other agents. We derive a nonlinear diffusion equation for the average occupancy of the discrete agent-based model for myopic agents. In contrast, interacting blind agents have a constant probability of movement to each of their nearest-neighbor sites, giving rise to a linear diffusion equation. Insight into the various terms in the nonlinear diffusion coefficient is obtained from a study of multiple subpopulations of interacting myopic agents, where an advection-diffusion equation for each subpopulation is derived, and from tracking an individual agent within the crowd, where a motility coefficient is extracted. Averaged discrete simulation data compares very well with the solution to the continuum models. We also compare the behavior of myopic and blind agents. The myopic motility mechanism is biologically motivated to emulate information an individual cell gathers from environment cues. The multispecies model developed and investigated here assists with the interpretation of experimental data involving the tracking subpopulations of cells within a total cell population.

  2. Human-robot interaction strategies for walker-assisted locomotion

    CERN Document Server

    Cifuentes, Carlos A

    2016-01-01

    This book presents the development of a new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation. The aim is to achieve a closer interaction between the robotic device and the individual, empowering the rehabilitation potential of such devices in clinical applications. A new multimodal human-robot interface for testing and validating control strategies applied to robotic walkers for assisting human mobility and gait rehabilitation is presented. Trends and opportunities for future advances in the field of assistive locomotion via the development of hybrid solutions based on the combination of smart walkers and biomechatronic exoskeletons are also discussed. .

  3. Dandy-Walker Malformation Presenting with Psychological Manifestations.

    Science.gov (United States)

    Rohanachandra, Yasodha Maheshi; Dahanayake, Dulangi Maneksha Amerasinghe; Wijetunge, Swarna

    2016-01-01

    Dandy-Walker malformation, which is a congenital malformation of the cerebellum, is documented in literature to be associated with psychotic symptoms, obsessive compulsive symptoms, mood symptoms, hyperactivity, and impulsive behavior. The pathogenesis of psychiatric symptoms in Dandy-Walker malformation is thought to be due to disruption of the corticocerebellar tracts, resulting in what is known as cerebellar cognitive affective syndrome. We present a case of Dandy-Walker malformation presenting with psychiatric symptoms. This case highlights the necessity to be aware of psychiatric manifestations of cerebellar disease as it has an impact on the diagnosis and treatment.

  4. Dandy-Walker Malformation Presenting with Psychological Manifestations

    Directory of Open Access Journals (Sweden)

    Yasodha Maheshi Rohanachandra

    2016-01-01

    Full Text Available Dandy-Walker malformation, which is a congenital malformation of the cerebellum, is documented in literature to be associated with psychotic symptoms, obsessive compulsive symptoms, mood symptoms, hyperactivity, and impulsive behavior. The pathogenesis of psychiatric symptoms in Dandy-Walker malformation is thought to be due to disruption of the corticocerebellar tracts, resulting in what is known as cerebellar cognitive affective syndrome. We present a case of Dandy-Walker malformation presenting with psychiatric symptoms. This case highlights the necessity to be aware of psychiatric manifestations of cerebellar disease as it has an impact on the diagnosis and treatment.

  5. Instability of Walker propagating domain wall in magnetic nanowires.

    Science.gov (United States)

    Hu, B; Wang, X R

    2013-07-12

    The stability of the well-known Walker propagating domain wall (DW) solution of the Landau-Lifshitz-Gilbert equation is analytically investigated. Surprisingly, a propagating DW is always dressed with spin waves so that the Walker rigid-body propagating DW mode does not occur in reality. In the low field region only stern spin waves are emitted while both stern and bow waves are generated under high fields. In a high enough field, but below the Walker breakdown field, the Walker solution could be convective or absolute unstable if the transverse magnetic anisotropy is larger than a critical value, corresponding to a significant modification of the DW profile and DW propagating speed.

  6. Walker Branch Watershed Vegetation Inventory, 1967-2006, R1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains five data files, in comma-separated format (.csv), derived from the Walker Branch Watershed (WBW) vegetation inventory in eastern Tennessee....

  7. Walker Branch Watershed Vegetation Inventory, 1967-1997

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The original objectives of the long-term vegetation survey of Walker Branch Watershed in eastern Tennessee (WBW; Curlin and Nelson 1968) was to quantify...

  8. Dandy-Walker malformation: a rare association with hypoparathyroidism.

    Science.gov (United States)

    Coban, Dilek; Akin, Mustafa Ali; Kurtoglu, Selim; Oktem, Suat; Yikilmaz, Ali

    2010-12-01

    Dandy-Walker malformation is characterized by cystic dilatation of the fourth ventricle and an enlarged posterior cranial fossa with upward displacement of the tentorium, lateral sinuses, and torcular, with agenesis or hypoplasia of the cerebellar vermis. Dandy-Walker malformation occurs in approximately the 4th week of gestation and is associated with various abnormalities involving the cardiac, skeletal, genitourinary, and gastrointestinal systems. The parathyroid gland also forms in the 3rd and 4th gestational weeks. Reported here is the case of a male infant with Dandy-Walker malformation with ventricular and atrial septal defect, unilateral renal agenesis, and hypoparathyroidism. To our knowledge, this rare association with neural crest events during the development of Dandy-Walker malformation has not been reported previously. Crown Copyright © 2010. Published by Elsevier Inc. All rights reserved.

  9. Dandy-Walker variant associated with bipolar affective disorder.

    Science.gov (United States)

    Lingeswaran, Anand; Barathi, Deepak; Sharma, Gyaneswahr

    2009-07-01

    The Dandy-Walker malformation is a congenital brain malformation, typically involving the fourth ventricle and the cerebellum. To date, the Dandy-Walker syndrome has not been described in association with bipolar disorder type I mania, and therefore we briefly report the case of a Dandy-Walker variant associated with acute mania. A 10-year-old boy was brought by his mother to the outpatient clinic of the Department of Psychiatry of a tertiary care hospital, with symptoms of mania. The MRI brain of the patient showed a posterior fossa cystic lesion, a giant cisterna magna communicating with the fourth ventricle and mild hypoplasia of the cerebellar vermis, with the rest of the structures being normal and no signs of hydrocephalus. These findings showed that the patient had a Dandy-Walker variant. He responded partially to valproate and olanzepine, which controlled the acute manic symptoms in the ward.

  10. SYMMETRY AS CONCEPTUAL METAPHOR IN WALKER'S THE COLOR PURPLE

    OpenAIRE

    Elena Tapia

    2003-01-01

    The author analyzes three types of the conceptual metaphor of embodied symmetry in Alice Walker's novel, The color purple (1982). These metaphorical projections, perceived as equilibrium and its breakage in abstract phenomena, enable readers to reexamine issues of race, non-traditional families, and gender roles. The dis/equilibrium emerges in the novel's epistolary structure. Biological equilibrium breaks in incidents of rape and incest. Walker creates characters in ...

  11. A Rare Cause of Congenital Hypotonia: Walker Warburg Syndrome

    OpenAIRE

    Cigdem Sivrice

    2014-01-01

    Walker-Warburg syndrome (WWS) is an autosomal recessive rare muscle disease which characterized by type 2 lissencephaly, cerebellar abnormalities, and congenital muscular dystrophy of the retinal abnormalities. In this article, we described a patient who born from 1st degree consanguineous marriage mother and father and admitted to our hospital suction weakness and had been diagnosed Walker- Warburg syndrome with physical examination and laboratory tests as a result of severe hypotonia, atypi...

  12. Dandy-Walker Malformation Associated with Neurocutaneous Melanosis

    Science.gov (United States)

    Cho, In Yong; Kim, Sung-Hak

    2011-01-01

    Neurocutaneous melanosis associated with Dandy-Walker malformation is a rare dysmorphogenesis that is associated with single or multiple giant pigmented cutaneous nevi and diffuse involvement of the central nervous system. In this article, we present a 2-month-old patient with neurocutaneous melanosis associated with Dandy-Walker malformation. In addition, we reviewed the literature and discussed the pathogenesis based on the preferred hypotheses. PMID:22259699

  13. ACADEMIC TRAINING (R.P. Walker)

    CERN Multimedia

    Françoise Benz

    2002-01-01

    15, 16, 17 May LECTURE SERIES from 11.00 to 12.00 hrs - Council room, bldg. 503 on 15 May, Auditorium, bldg. 500 on 16 and 17 May Introduction to free electron lasers by R.P. Walker / Rutherford Laboratory, UK The Free-electron laser (FEL) is a source of coherent electromagnetic radiation based on a relativistic electron beam. First operated 25 years ago, the FEL has now reached a stage of maturity for operation in the infra-red region of the spectrum and several facilities provide intense FEL radiation beams for research covering a wide range of disciplines. Several projects both underway and proposed aim at pushing the minimum wavelength from its present limit around 100 nm progressively down to the 1 Angstrom region where the X-ray FEL would open up many new and exciting research possibilities. Other developments aim at increasing power levels to the 10's of kW level. In this series of lectures we give an introduction to the basic principles of FELs and their different modes of operation, and summarise the...

  14. Neurodevelopment in preschool idiopathic toe-walkers.

    Science.gov (United States)

    Martín-Casas, P; Ballestero-Pérez, R; Meneses-Monroy, A; Beneit-Montesinos, J V; Atín-Arratibel, M A; Portellano-Pérez, J A

    2017-09-01

    Idiopathic toe walking, a differential diagnosis for neurological and orthopaedic disorders, has been associated with neurodevelopmental alterations. Neurodevelopmental assessment at early ages using specific tests may improve management and follow-up of these patients. The aim of our study is to analyse the neurodevelopmental characteristics of preschool idiopathic toe-walkers (ITW) by comparing them to a control group. Our descriptive cross-sectional study compared possible risk factors, neurodevelopmental characteristics, and scores on the Child Neuropsychological Maturity Questionnaire (CUMANIN) between a group of 56 ITWs aged 3 to 6 and a control group including 40 children. The proportion of males was significantly higher in the ITW group (P=.008). The percentage of patients with a family history (P=.000) and biological risk factors during the perinatal period (P=.032) was also higher in this group. According to the parents' reports, motor coordination in ITWs was significantly poorer (59%; P=.009). ITWs scored significantly lower on CUMANIN subscales of psychomotricity (=0,001) and memory (P=.001), as well as in verbal development (P=.000), non-verbal development (P=.026), and overall development (P=.004). Foot preference was less marked in the ITW group (P=.047). The neurodevelopmental characteristics of our sample suggest that idiopathic toe walking is a marker of neurodevelopmental impairment. However, further studies are necessary to confirm these findings. Copyright © 2016 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Experimental model of ultrasound thermotherapy in rats inoculated with Walker-236 tumor Modelo experimental de termoterapia ultrassônica em ratos inoculados com tumor de Walker-236

    Directory of Open Access Journals (Sweden)

    José Antonio Carlos Otaviano David Morano

    2011-01-01

    Full Text Available PURPOSE: To develop a model to evaluate the effects of focal pulsed ultrasound (US waves as a source of heat for treatment of murine subcutaneous implanted Walker tumor. METHODS: An experimental, controlled, comparative study was conducted. Twenty male Wistar rats (160-300 g randomized in 2 equal groups (G-1: Control and G-2: Hyperthermia were inoculated with Walker-256 carcinosarcoma tumor. After 5 days G-2 rats were submitted to 45ºC hyperthermia. Heat was delivered directly to the tumor by an ultrasound (US equipment (3 MHz frequency, 1,5W/cm³. Tumor temperature reached 45º C in 3 minutes and was maintained at this level for 5 minutes. Tumor volume was measured on days 5, 8, 11, 14 e 17 post inoculation in both groups. Unpaired t-test was used for comparison. POBJETIVO: Desenvolver um modelo para avaliar os efeitos do ultra-som focal pulsado como fonte de calor para o tratamento de tumores de Walker subcutâneos implantados em ratos. MÉTODOS: Um estudo experimental, controlado, comparativo foi realizado. Vinte ratos Wistar machos (160-300 g divididos em dois grupos (G-1: Controle e G-2: hipertermia foram inoculados com tumor de Walker carcinossarcoma-256. Após cinco dias os ratos do grupo G-2 ratos foram submetidos a hipertermia (45ºC. O calor foi aplicado diretamente no tumor por um equipamento de ultrassonografia (3 MHz, 1,5 W/cm³. A temperatura no tumor atingiu 45ºC em 3 minutos e foi mantida nesse nível por 5 minutos. O volume do tumor foi medido nos dias 5, 8, 11, 14 e 17 após a inoculação, em ambos os grupos. Teste t não pareado foi utilizado para comparação. P <0,05 foi considerado significante. RESULTADOS: O volume do tumor foi significativamente maior no 5º dia e diminuiu nos dias 11, 14 e 17 nos ratos tratados. Animais submetidos à hipertermia sobreviveram mais tempo que os animais do grupo controle. No 29º dia após a inoculação do tumor, 40% dos ratos do grupo controle e 77,78% dos ratos tratados com

  16. Multiple Walkers in the Wang-Landau Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G

    2005-12-28

    The mean cost for converging an estimated density of states using the Wang-Landau algorithm is measured for the Ising and Heisenberg models. The cost increases in a power-law fashion with the number of spins, with an exponent near 3 for one-dimensional models, and closer to 2.4 for two-dimensional models. The effect of multiple, simultaneous walkers on the cost is also measured. For the one-dimensional Ising model the cost can increase with the number of walkers for large systems. For both the Ising and Heisenberg models in two-dimensions, no adverse impact on the cost is observed. Thus multiple walkers is a strategy that should scale well in a parallel computing environment for many models of magnetic materials.

  17. [Congenital generalized lipodystrophy in a patient with Dandy Walker anomaly].

    Science.gov (United States)

    Luna, Cecilia Inés; Fernández Cordero, Marisa; Escruela, Romina; Sierra, Valeria; Córdoba, Antonela; Goñi, Ignacio María; Berridi, Ricardo

    2014-10-01

    The objective of this study is to describe the unexpected association between the congenital generalized lipodystrophy (CGL) and Dandy Walker anomaly. We report the case of a 1-year-old infant who was hospitalized at her fourth month of life with Dandy Walker anomaly diagnosis and an increased social risk. During her hospitalization, she developed progressively: acromegaloid aspect, triangular fascia, hirsutism, lipoatrophy, muscle hypertrophy, clitoromegaly, abdominal distention, progressive hepatomegaly, and hypertriglyceridemia. This led to the clinical diagnosis of congenital generalized lipodystrophy. Importance should be given to the examination of clinical aspects as well as the interdisciplinary follow-up for proper detection of insulin resistance and diabetes, early puberty, cardiomyopathy, among others. In case of Dandy Walker anomaly, it should be checked the evolution to search intracranial hypertension signs. Due to its autosomal recessive nature, it is important to provide genetic counseling to the parents.

  18. Retinal vascular nonperfusion in siblings with Dandy-Walker variant.

    Science.gov (United States)

    Rusu, Irene; Gupta, Mrinali Patel; Patel, Samir N; Oltra, Erica; Chan, R V Paul

    2016-04-01

    We report the case of a 2-month-old girl with Dandy-Walker variant who presented with strabismus, pathologic myopia measuring -16.00 D in each eye, diffuse chorioretinal atrophy and pigment mottling in the macula of both eyes, and areas of retinal capillary nonperfusion in both eyes. The patient's brother also has Dandy-Walker variant and was found to have bilateral severe myopia, myopic fundi, tilted optic disks with peripapillary atrophy, extensive areas of white without pressure, areas of lattice degeneration, and several chronic-appearing atrophic retinal holes surrounded by pigmentation. We hypothesize that children with Dandy-Walker variant may present with refractive errors such as pathologic myopia and with diverse retinal findings, including retinal ischemia. A lower threshold for ophthalmologic examination may be considered in this population. Copyright © 2016 American Association for Pediatric Ophthalmology and Strabismus. Published by Elsevier Inc. All rights reserved.

  19. Dandy walker variant and bipolar I disorder with graphomania.

    Science.gov (United States)

    Can, Serdar Suleyman; Karakaş Uğurlu, Görkem; Cakmak, Selcen

    2014-07-01

    Cerebellum is known to play an important role in coordination and motor functions. In some resent studies it is also considered to be involved in modulation of mood, cognition and psychiatric disorders. Dandy Walker Malformation is a congenital malformation that is characterized by hypoplasia or aplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle and enlargement of the posterior fossa. When the volume of posterior fossa is normal, the malformation is called Dandy Walker Variant. Case is a 32 year old male with a 12 year history of Bipolar I Disorder presented with manic and depresive symptoms, including dysphoric and depressive affect, anhedonia, suicidal thoughts and behaviours, thoughts of fear about future, overtalkativeness and graphomania, increased energy, irregular sleep, loss of appetite, increased immersion in projects, irritability, agressive behavior, impulsivity. Cranial Magnetic Resonance Imaging was compatible to the morphological features of Dandy Walker Variant.

  20. Dandy-Walker malformation: analysis of 19 cases.

    Science.gov (United States)

    Alexiou, George A; Sfakianos, George; Prodromou, Neofytos

    2010-02-01

    Dandy-Walker malformation is a congenital disorder that involves the cerebellum and fourth ventricle. Regarding treatment, there is still controversy over the optimum surgical management. In the current study, we present 19 consecutive cases of Dandy-Walker malformation diagnosed between January 1992 and January 2008 that were treated in our institute. All patients presented with hydrocephalus at the time of diagnosis and were treated surgically. Combined drainage of the ventricular system and posterior fossa cyst, using a 3-way connector was performed in 5 patients. Posterior fossa cyst drainage alone was performed in 10 patients and the remaining 4 patients were treated by ventricular drainage alone. All patients improved after treatment. Dandy-Walker malformation is a developmental abnormality of the central nervous system associated with various brain and extracranial abnormalities. Surgical treatment remains controversial, whereas prognosis varies greatly according to the severity of syndrome and associated comorbidities.

  1. [Dandy-walker syndrome and microdeletions on chromosome 7].

    Science.gov (United States)

    Liao, Can; Fu, Fang; Li, Ru; Pan, Min; Yang, Xin; Yi, Cui-xing; Li, Jian; Li, Dong-zhi

    2012-02-01

    To investigate genetic etiology of Dandy-Walker syndrome with array-based comparative genomic hybridization (array-CGH). Eight fetuses with Dandy-Walker malformations but normal karyotypes by conventional cytogenetic technique were selected. DNA samples were extracted and hybridized with Affymetrix cytogenetic 2.7 M arrays by following the manufacturer's standard protocol. The data were analyzed by special software packages. By using array-CGH technique, common deletions and duplication on chromosome 7p21.3 were identified in three cases, within which were central nervous system disease associated genes NDUFA4 and PHF14. Copy number variations (CNVs) of chromosome 7p21.3 region are associated with Dandy-Walker malformations which may be due to haploinsufficiency or overexpression of NDUFA4 and PHF14 genes.

  2. Dandy-Walker Malformation Presenting with Affective Symptoms.

    Science.gov (United States)

    Batmaz, Mert; Balçik, Zeynep Ezgi; Özer, Ürün; Hamurişçi Yalçin, Burcu; Özen, Şakir

    2017-09-01

    Dandy-Walker malformation is defined by enlarged posterior fossa, cystic dilatation of the fourth ventricle, and cerebellar hypoplasia. Although developmental delay and mental retardation are common in Dandy-Walker malformation cases, other comorbid psychiatric conditions have been rarely reported. There are limited numbers of case reports about comorbidity of bipolar disorder with Dandy-Walker malformation in the literature. Herein, a Dandy-Walker malformation case presenting affective symptoms is reported, and psychiatric symptoms which might be seen in this rare malformation are discussed along with diagnosis, treatment, and follow-up processes. A 27-year-old male patient, hospitalized for compulsory treatment, had been diagnosed with Dandy-Walker malformation in childhood. First complaints were attention deficiency, behavioral problems, learning difficulties; and manic and depressive episodes have occurred during follow-ups. He recently complained of decreased need for sleep, irritability, and increased speed of thought, and psychiatric examination was consistent with manic episode. Cranial computed tomography (CT) revealed bilateral ventriculomegaly, enlarged third and fourth ventricles with posterior fossa cyst, and cerebellar hypoplasia. His treatment included 30 mg/day aripiprazole, 1000 mg/day valproic acid, 200 mg/day quetiapine, 4 mg/day biperiden, and 100 mg/month paliperidone palmitate. Beside its traditional role in the regulation of coordination and motor functions, cerebellum is increasingly emphasized for its involvement in the mood regulation. Thus, as seen in Dandy-Walker malformation, cerebellar anomalies are suggested to play a role in the pathophysiology of mood disorders. Further studies are needed to better understand the relationship between mood disorders and cerebellum. Moreover, treatment options should be considered carefully in terms of resistance to treatment and potential side effects, for psychiatric disorders occurring in these

  3. A Rare Cause of Congenital Hypotonia: Walker Warburg Syndrome

    Directory of Open Access Journals (Sweden)

    Cigdem Sivrice

    2014-08-01

    Full Text Available Walker-Warburg syndrome (WWS is an autosomal recessive rare muscle disease which characterized by type 2 lissencephaly, cerebellar abnormalities, and congenital muscular dystrophy of the retinal abnormalities. In this article, we described a patient who born from 1st degree consanguineous marriage mother and father and admitted to our hospital suction weakness and had been diagnosed Walker- Warburg syndrome with physical examination and laboratory tests as a result of severe hypotonia, atypical facial appearance, accompanying eye and brain abnormalities are very high serum creatine phosphokinase levels and wanted to draw attention to this rare muscle disease in the differential diagnosis of hypotonic infants.

  4. Evolving digital ecological networks.

    Directory of Open Access Journals (Sweden)

    Miguel A Fortuna

    Full Text Available "It is hard to realize that the living world as we know it is just one among many possibilities" [1]. Evolving digital ecological networks are webs of interacting, self-replicating, and evolving computer programs (i.e., digital organisms that experience the same major ecological interactions as biological organisms (e.g., competition, predation, parasitism, and mutualism. Despite being computational, these programs evolve quickly in an open-ended way, and starting from only one or two ancestral organisms, the formation of ecological networks can be observed in real-time by tracking interactions between the constantly evolving organism phenotypes. These phenotypes may be defined by combinations of logical computations (hereafter tasks that digital organisms perform and by expressed behaviors that have evolved. The types and outcomes of interactions between phenotypes are determined by task overlap for logic-defined phenotypes and by responses to encounters in the case of behavioral phenotypes. Biologists use these evolving networks to study active and fundamental topics within evolutionary ecology (e.g., the extent to which the architecture of multispecies networks shape coevolutionary outcomes, and the processes involved.

  5. The role of walkers' needs and expectations in supporting maintenance of attendance at walking groups: a longitudinal multi-perspective study of walkers and walk group leaders.

    Directory of Open Access Journals (Sweden)

    Aikaterini Kassavou

    Full Text Available There is good evidence that when people's needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers' needs and walk leaders' actions to address them. The present study was aimed at addressing both of these gaps in the research.Two preliminary thematic analyses were conducted on face-to-face interviews with (a eight walkers when they joined walking groups, five of whom were interviewed three months later, and (b eight walk leaders. A multi-perspective analysis building upon these preliminary analyses identified similarities and differences within the themes that emerged from the interviews with walkers and walk leaders.Walkers indicated that their main needs and expectations when joining walking groups were achieving long-term social and health benefits. At the follow up interviews, walkers indicated that satisfaction with meeting similar others within the groups was the main reason for continued attendance. Their main source of dissatisfaction was not feeling integrated in the existing walking groups. Walk leaders often acknowledged the same reasons for walkers joining and maintaining attendance at walking. However, they tended to attribute dissatisfaction and drop out to uncontrollable environmental factors and/or walkers' personalities. Walk leaders reported a lack of efficacy to effectively address walkers' needs.Interventions to increase retention of walkers should train walk leaders with the skills to help them modify the underlying psychological factors affecting walkers' maintenance at walking groups. This should result in greater retention of walkers in walking

  6. The role of walkers' needs and expectations in supporting maintenance of attendance at walking groups: a longitudinal multi-perspective study of walkers and walk group leaders.

    Science.gov (United States)

    Kassavou, Aikaterini; Turner, Andrew; French, David P

    2015-01-01

    There is good evidence that when people's needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers' needs and walk leaders' actions to address them. The present study was aimed at addressing both of these gaps in the research. Two preliminary thematic analyses were conducted on face-to-face interviews with (a) eight walkers when they joined walking groups, five of whom were interviewed three months later, and (b) eight walk leaders. A multi-perspective analysis building upon these preliminary analyses identified similarities and differences within the themes that emerged from the interviews with walkers and walk leaders. Walkers indicated that their main needs and expectations when joining walking groups were achieving long-term social and health benefits. At the follow up interviews, walkers indicated that satisfaction with meeting similar others within the groups was the main reason for continued attendance. Their main source of dissatisfaction was not feeling integrated in the existing walking groups. Walk leaders often acknowledged the same reasons for walkers joining and maintaining attendance at walking. However, they tended to attribute dissatisfaction and drop out to uncontrollable environmental factors and/or walkers' personalities. Walk leaders reported a lack of efficacy to effectively address walkers' needs. Interventions to increase retention of walkers should train walk leaders with the skills to help them modify the underlying psychological factors affecting walkers' maintenance at walking groups. This should result in greater retention of walkers in walking groups, thereby

  7. Alice Walker in the Classroom: "Living by the Word." The NCTE High School Literature Series.

    Science.gov (United States)

    Jago, Carol

    This small book is a handy guide for bringing the work of author Alice Walker into the classroom. It includes biographical information, ideas for literature circles using Walker's short stories, sample writing lessons using Walker's poems, suggestions for teaching "The Color Purple," and a wealth of resources for further investigation of…

  8. 75 FR 35279 - Revocation of Regulations Banning Certain Baby-Walkers

    Science.gov (United States)

    2010-06-21

    ... section G of this notice.) 2. Recent statutory changes affecting baby-walkers. The Consumer Product Safety... standard for infant walkers, based largely on the provisions of the current ASTM voluntary standard. Given... Specification for Infant Walkers (ASTM F977-07) is published by the American Society for Testing and Materials...

  9. 75 FR 24753 - The Walker Auto Group, Inc., Miamisburg, OH; Notice of Negative Determination Regarding...

    Science.gov (United States)

    2010-05-05

    ... Employment and Training Administration The Walker Auto Group, Inc., Miamisburg, OH; Notice of Negative... TAA petition filed on behalf of workers at The Walker Auto Group, Inc., Miamisburg, Ohio, was based on... Walker Auto Group, Inc., Miamisburg, Ohio, supplies a service (sales and service of Pontiac automobiles...

  10. Karyotype and meiosis studies in Oxycatantops spissus (Walker ...

    African Journals Online (AJOL)

    The standard karyotype of Oxycatantops spissus (Walker) (Orthoptera: Acrididae: Acridinae) from Limbe in the South West Province of Cameroon, comprises 2n = 23 acrocentric chromosomes in the male with the XO/XX sex determining mechanism [2n = 23 (22AA+XO)]. The karyotype structure is represented by five pairs of ...

  11. Karyotype and meiosis studies in Oxycatantops spissus (Walker ...

    African Journals Online (AJOL)

    RHUMSIKI

    The standard karyotype of Oxycatantops spissus (Walker) (Orthoptera: Acrididae: Acridinae) from. Limbe in the South West Province of Cameroon, comprises 2n = 23 acrocentric chromosomes in the male with the XO/XX sex determining mechanism [2n = 23 (22AA+XO)]. The karyotype structure is represented by five pairs of ...

  12. Hazard Patterns and Injury Prevention with Infant Walkers and Strollers.

    Science.gov (United States)

    Wishon, Phillip M.; And Others

    Mindful of the potential hazards associated with products intended for young children, this article examines pediatric accidents involving strollers and walkers. According to the latest figures available from the National Electronic Injury Surveillance System of the United States (NEISS), more than 11,800 stroller injuries in 1987 were serious…

  13. A methodology to calibrate pedestrian walker models using multiple objectives

    NARCIS (Netherlands)

    Campanella, M.C.; Daamen, W.; Hoogendoorn, S.P.

    2012-01-01

    The application of walker models to simulate real situations require accuracy in several traffic situations. One strategy to obtain a generic model is to calibrate the parameters in several situations using multiple-objective functions in the optimization process. In this paper, we propose a general

  14. winged females of the cricket Gryllodes supplicans (Walker)

    African Journals Online (AJOL)

    other orders of insects (Jago 1985; Masaki & Walker 1987;. Roff 1990). In several of !.hese cases, including the one under discussion, the two forms were originally described in different genera. One of the mOSt imJXlrtant reasons for regarding the two fonns of G. supp/icans as one species is !.he fact !.hat winged forms ...

  15. David Walker Receives 2010 Harry H. Hess Medal

    Science.gov (United States)

    Agee, Carl B.; Walker, David

    2011-01-01

    David Walker was awarded the 2010 Harry H. Hess Medal at the AGU Fall Meeting Honors Ceremony, held on 15 December 2010 in San Francisco, Calif. The medal is for “outstanding achievements in research of the constitution and evolution of Earth and other planets.”

  16. 75 FR 35265 - Safety Standard for Infant Walkers: Final Rule

    Science.gov (United States)

    2010-06-21

    ... demonstrated the adequacy of the stability test in the ASTM F 977-07 standard. G. Effective Date The Commission... as a voluntary standard developed by ASTM International (formerly known as the American Society for Testing and Materials), ASTM F 977-07, Standard Consumer Safety Specification for Infant Walkers, but with...

  17. Dandy-Walker malformation | Hamid | Egyptian Journal of Medical ...

    African Journals Online (AJOL)

    Dandy-Walker malformation is a rare congenital malformation and involves the cerebellum and fourth ventricle. The condition is characterized by agenesis or hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa. A large number of concomitant problems may be ...

  18. A new species of Culcua Walker (Diptera: Stratiomyidae) from Vietnam

    Science.gov (United States)

    A new species of Culcua Walker (Diptera: Stratiomyidae), C. lingafelteri Woodley, new species, is described from northern Vietnam. It is diagnosed relative to other species using the recent revision of the genus by Rozkošný and Kozánek (2007). This is the first species of Culcua reported from Viet...

  19. Spruce aphid (Elatobium abietinum Walker) (Hemiptera: Aphididae) [Chapter XXIV

    Science.gov (United States)

    Ann M. Lynch

    2014-01-01

    Elatobium abietinum Walker is a spruce-feeding aphid that in Europe is referred to as the green spruce aphid (Day et al., 1998a) (Fig. 1). However, in North America E. abietinum is known simply as the spruce aphid, while the common name "green spruce aphid" refers to a different species, Cinara fornacula Hottes (Hemiptera: Aphididae) (http://www.entsoc.org/...

  20. Bathymetry of Walker Lake, West-Central Nevada

    Science.gov (United States)

    Lopes, Thomas J.; Smith, J. LaRue

    2007-01-01

    Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Much of the streamflow in the Walker River is diverted for irrigation, which has contributed to a decline in lake-surface altitude of about 150 feet and an increase in dissolved solids from 2,500 to 16,000 milligrams per liter in Walker Lake since 1882. The increase in salinity threatens the fresh-water ecosystem and survival of the Lahontan cutthroat trout, a species listed as threatened under the Endangered Species Act. Accurately determining the bathymetry and relations between lake-surface altitude, surface area, and storage volume are part of a study to improve the water budget for Walker Lake. This report describes the updated bathymetry of Walker Lake, a comparison of results from this study and a study by Rush in 1970, and an estimate of the 1882 lake-surface altitude. Bathymetry was measured using a single-beam echosounder coupled to a differentially-corrected global positioning system. Lake depth was subtracted from the lake-surface altitude to calculate the altitude of the lake bottom. A Lidar (light detection and ranging) survey and high resolution aerial imagery were used to create digital elevation models around Walker Lake. The altitude of the lake bottom and digital elevation models were merged together to create a single map showing land-surface altitude contours delineating areas that are currently or that were submerged by Walker Lake. Surface area and storage volume for lake-surface altitudes of 3,851.5-4,120 feet were calculated with 3-D surface-analysis software. Walker Lake is oval shaped with a north-south trending long axis. On June 28, 2005, the lake-surface altitude was 3,935.6 feet, maximum depth was 86.3 feet, and the surface area was 32,190 acres. The minimum altitude of the lake bottom from discrete point depths is 3,849.3 feet near the center of Walker Lake. The lake bottom is remarkably smooth except for mounds near

  1. Philip Glass, Scott Walker ja Sigur Ros! / Immo Mihkelson

    Index Scriptorium Estoniae

    Mihkelson, Immo, 1959-

    2007-01-01

    Pimedate Ööde 11. filmifestivali muusikafilme - Austraalia "Glass: Philipi portree 12 osas" (rež. Scott Hicks), Islandi "Sigur Ros kodus" (rež. Dean DeBois), Suurbritannia "Scott Walker: 30 Century Man" (rež. Stephen Kijak)

  2. Mapping a Memoir within Australian Landscapes: Shirley Walker

    Directory of Open Access Journals (Sweden)

    Alejandra Moreno Álvarez

    2012-10-01

    Full Text Available Shirley Walker (1927, retired Senior Lecturer in English from the University of New England at Armidale, where she taught Australian Literature, decided to try her own hand at writing a memoir. The result is Roundabout at Bangalow: An Intimate Chronicle (2001, which is her account of growing up in the Northern Rivers area of New South Wales in Australia. The author has also published numerous critical articles on Australian Literature, commenting thoroughly on the work of Mary Gilmore (1865- 1962, Judith Wright (1915-2000 and Dorothy Hewett (1923-2002. Walker has also published The Ghost at the Wedding (2009 based on the life of Walker’s mother in law, a woman whose life was largely shaped by war, and who, in 1918 near the end of WW1, married a returned soldier. This biography, which was awarded the Asher Literary Prize (2009 and the Nita B Kibble Award (2010, Australia’s premier award for women’s writing, has been described as a major work of Australian literature and a major contribution to Australian history. The present article focuses on Roundabout at Bangalow: An Intimate Chronicle, where Walker narrates the complicated and, sometimes, blurred resonances of her “half-a-lifetime” memoir. This work exemplifies how Walker is deeply concerned with the unreliability of memory and the way it can exaggerate grievances or distort past perceptions, unloosing itself from historical and geographical truth and adopting first and foremost a primal function in the formation of identities.

  3. Bobble-Head Doll and Dandy-Walker Syndromes

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2007-10-01

    Full Text Available A female infant with macrocephaly (head circumference >95th%, hydrocephalus, and Dandy-Walker syndrome, who developed horizontal head movements of the 'no-no' type at 1 year of age, is reported from Federal University of Minas Gerais, and other centers in Brazil.

  4. Nursery Pest Management of Phytolyma lata Walker (Scott) Attack ...

    African Journals Online (AJOL)

    The establishment of plantations of Milicia excelsa has been constrained by the gall-forming psyllid Phytolyma lata Walker (Scott) that causes extensive damage to young plants. We present findings of an experiment aimed at preventing Phytolyma attack on Milicia seedlings in the nursery using chemical control and ...

  5. Revalidation of Ceresa terminalis walker and its placement in Stictocephala Stål (Hemiptera, Membracidae Revalidação de Ceresa terminalis walker e sua alocação em Stictocephala Stål (Hemiptera, Membracidae

    Directory of Open Access Journals (Sweden)

    Gabriel S. de Andrade

    2005-12-01

    Full Text Available Ceresa terminalis Walker, 1851 is reinstated and transferred to Stictocephala Stål, 1869: Stictocephala terminalis (Walker, 1851 sp. rev., comb. nov.Ceresa terminalis Walker, 1851 é revalidada e transferida para Stictocephala Stål, 1869: Stictocephala terminalis (Walker, 1851 sp. rev., comb. nov.

  6. Mentoring: An Evolving Relationship.

    Science.gov (United States)

    Block, Michelle; Florczak, Kristine L

    2017-04-01

    The column concerns itself with mentoring as an evolving relationship between mentor and mentee. The collegiate mentoring model, the transformational transcendence model, and the humanbecoming mentoring model are considered in light of a dialogue with mentors at a Midwest university and conclusions are drawn.

  7. Measurably evolving populations

    DEFF Research Database (Denmark)

    Drummond, Alexei James; Pybus, Oliver George; Rambaut, Andrew

    2003-01-01

    processes through time. Populations for which such studies are possible � measurably evolving populations (MEPs) � are characterized by sufficiently long or numerous sampled sequences and a fast mutation rate relative to the available range of sequence sampling times. The impact of sequences sampled through...... understanding of evolutionary processes in diverse organisms, from viruses to vertebrates....

  8. Reduced incidence of cardiac arrhythmias in walkers and runners.

    Directory of Open Access Journals (Sweden)

    Paul T Williams

    Full Text Available Walking is purported to reduce the risk of atrial fibrillation by 48%, whereas jogging is purported to increase its risk by 53%, suggesting a strong anti-arrhythmic benefit of walking over running. The purpose of these analyses is to compare incident self-reported physician-diagnosed cardiac arrhythmia to baseline energy expenditure (metabolic equivalent hours per day, METhr/d from walking, running and other exercise.Proportional hazards analysis of 14,734 walkers and 32,073 runners.There were 1,060 incident cardiac arrhythmias (412 walkers, 648 runners during 6.2 years of follow-up. The risk for incident cardiac arrhythmias declined 4.4% per baseline METhr/d walked by the walkers, or running in the runners (P = 0.0001. Specifically, the risk declined 14.2% (hazard ratio: 0.858 for 1.8 to 3.6 METhr/d, 26.5% for 3.6 to 5.4 METhr/d, and 31.7% for ≥5.4 METhr/d, relative to <1.8 METhr/d. The risk reduction per METhr/d was significantly greater for walking than running (P<0.01, but only because walkers were at 34% greater risk than runners who fell below contemporary physical activity guideline recommendations; otherwise the walkers and runners had similar risks for cardiac arrhythmias. Cardiac arrhythmias were unrelated to walking and running intensity, and unrelated to marathon participation and performance.The risk for cardiac arrhythmias was similar in walkers and runners who expended comparable METhr/d during structured exercise. We found no significant risk increase for self-reported cardiac arrhythmias associated with running distance, exercise intensity, or marathon participation. Rhythm abnormalities were based on self-report, precluding definitive categorization of the nature of the rhythm disturbance. However, even if the runners' arrhythmias include sinus bradycardia due to running itself, there was no increase in arrhythmias with greater running distance.

  9. Entrevista al profesor D. Michael Walker. - Interview with Professor D. Michael Walker.

    Directory of Open Access Journals (Sweden)

    Caravaca Guerrero, Consuelo Isabel

    2014-12-01

    Full Text Available Entrevistar a un investigador de la talla de D. Michael Walker supone hablar de un investigador reconocido a nivel nacional e internacional, uno de los mayores expertos en evolución humana de nuestros días. Nació en Colchester (Inglaterra en 1941 y tiene doble nacionalidad: británica y australiana. Actualmente es profesor emérito de la Universidad de Murcia en el Departamento de Zoología y Antropología Física de la Facultad de Biología. Pero su currículum no acaba aquí, Michael realizó tres carreras, Fisiología Animal, Medicina, y Arqueología Prehistórica, en la Universidad de Oxford. Es Doctor por esta universidad, gracias a su tesis leída sobre Paleoantropología y Prehistoria de las cuencas de los ríos Segura y Vinalopó. Nuestro entrevistado, también fue elegido Académico (Fellow –F.S.A.- en 1988 de la Society of Antiquaries of Londono SAL. Fundada en 1707, la SAL es la equivalente británica de la española Real Academia de la Historia. Es Fellow también del Real Instituto Antropológico de la Gran Bretaña (Royal Anthropological Institute of Great Britain y socio emérito de la Asociación Americana de Antropólogos Físicos (American Association of Physical Anthropologists.

  10. Developmental outcomes of Down syndrome and Dandy-Walker malformation

    Science.gov (United States)

    Love, Kaitlin; Huddleston, Lillie; Olney, Pat; Wrubel, David; Visootsak, Jeannie

    2012-01-01

    Dandy-Walker syndrome (DWS), or Dandy-Walker complex, is a congenital brain malformation of the posterior fossa, typically resulting in developmental delay and cognitive disability. The co-occurrence of Down syndrome (DS) and DWS is relatively uncommon; thus, its impact on developmental outcomes has not been fully elucidated. Herein, we report a case of a 37-month-old child with DS and DWS, who is functioning at the following age-equivalent: gross motor at a 9-mo level, fine motor 6 mo, expressive language 14 mo, receptive language 9 mo. As such, it is important to determine how the DWS influences developmental outcomes, and appreciate the importance of early interventional therapy. PMID:22866020

  11. Dandy-Walker syndrome with psychotic symptoms: a case report.

    Science.gov (United States)

    Buonaguro, Elisabetta F; Cimmarosa, Sara; de Bartolomeis, Andrea

    2014-01-01

    Here we report the case of a patient with psychotic symptoms apparently resistant to antipsychotic treatments. Since the last admission in a psychiatric division the patient was diagnosed with Bipolar Disorder type I and then referred to our Outpatients Unit of Treatment Resistant Psychosis, where she was subsequently re-diagnosed with Dandy-Walker Syndrome. The Dandy Walker Complex is a congenital brain malformation involving the fourth ventricle and the cerebellum. We investigated the cognitive impairment of the patient and found deficits prominently in executive functions. This report may add further evidence on the importance of a correct diagnosis prior to defining a patient as treatment resistant and highlights cerebellar dysfunctions that may contribute to neuropsychiatric symptoms and cognitive impairment.

  12. Dandy-Walker syndrome studied by computed tomography and pneumoencephalography

    Energy Technology Data Exchange (ETDEWEB)

    Masdeu, J.C. (Hines Veterans Administration Hospital, Maywood, IL); Dobben, G.D.; Azar-Kia, B.

    1983-04-01

    Based on air studies, some authors have disputed the ability of computed tomography (CT) to diagnose posterior fossa cysts. The authors correlated the pneumoencephalographic, CT, and pathological findings in 4 patients with classic Dandy-Walker syndrome. Three cases had been misdiagnosed as retrocerebellar arachnoid cysts because the fourth ventricle was incorrectly considered normal on brow-up or erect air studies, reflecting the inability of such studies to evaluate an agenetic vermis and deficient posterior medullary velum which are characteristic of Dandy-Walker malformation. Careful correlation with autopsy findings showed that even with complete agenesis of the inferior vermis, if the slit between the cerebellar hemispheres is narrow, the fourth ventricle could be misinterpreted as normal on pneumoencephalography and sagittal CT. Radionuclide studies, a small amount of air, or metrizamide may be needed to determine whether the cyst communicates with the subarachnoid space.

  13. Coarctation of the aorta associated with Dandy–Walker variant

    Science.gov (United States)

    Zhou, Li; Lui, George K.; Shenoy, Rajesh; Taub, Cynthia C.

    2013-01-01

    This article reports a rare case of coarctation of the aorta associated with Dandy–Walker variant in a 17-year-old girl. Differential diagnoses of coarctation of the aorta and Dandy–Walker variant are extensively discussed. In addition, standard surgical treatment of coarctation as well as new approaches such as endovascular stenting are described in detail to provide therapeutic insights into her management. Although surgical or endovascular repair of coarctation results in significant improvement of systemic hypertension and is associated with better survival, cardiovascular complications are still very common. Thus, long-term follow-up after repair is required, and high-quality imaging studies such as echocardiography, CT and MRI are warranted. PMID:24396258

  14. Coarctation of the aorta associated with Dandy-Walker variant.

    Science.gov (United States)

    Zhou, Li; Lui, George K; Shenoy, Rajesh; Taub, Cynthia C

    2013-09-01

    This article reports a rare case of coarctation of the aorta associated with Dandy-Walker variant in a 17-year-old girl. Differential diagnoses of coarctation of the aorta and Dandy-Walker variant are extensively discussed. In addition, standard surgical treatment of coarctation as well as new approaches such as endovascular stenting are described in detail to provide therapeutic insights into her management. Although surgical or endovascular repair of coarctation results in significant improvement of systemic hypertension and is associated with better survival, cardiovascular complications are still very common. Thus, long-term follow-up after repair is required, and high-quality imaging studies such as echocardiography, CT and MRI are warranted.

  15. Trigeminal neuralgia due to Dandy-Walker syndrome.

    Science.gov (United States)

    Zhang, Wenhao; Chen, Minjie; Zhang, Weijie

    2013-07-01

    Trigeminal neuralgia (TN) is a common pain in the orofacial region. Dandy-Walker syndrome (DWS) is a congenital malformation of the cerebellar and the fourth ventricle foramina atresia. Dandy-Walker syndrome is rarely found in patients with TN. This article presents a 36-year-old man with the symptoms of typical TN. His physical examination was entirely normal. An enhanced magnetic resonance imaging was taken. Magnetic resonance imaging revealed the bilateral lateral ventricle, the fourth and third ventricle significantly enlarged with severe obstructive hydrocephalus, a huge posterior fossa cyst connected with the fourth ventricle, and hypoplastic vermis. The pain was controlled by Tegretol. The reported case suggests that DWS is an unusual cause of TN.

  16. EVOLVE 2014 International Conference

    CERN Document Server

    Tantar, Emilia; Sun, Jian-Qiao; Zhang, Wei; Ding, Qian; Schütze, Oliver; Emmerich, Michael; Legrand, Pierrick; Moral, Pierre; Coello, Carlos

    2014-01-01

    This volume encloses research articles that were presented at the EVOLVE 2014 International Conference in Beijing, China, July 1–4, 2014.The book gathers contributions that emerged from the conference tracks, ranging from probability to set oriented numerics and evolutionary computation; all complemented by the bridging purpose of the conference, e.g. Complex Networks and Landscape Analysis, or by the more application oriented perspective. The novelty of the volume, when considering the EVOLVE series, comes from targeting also the practitioner’s view. This is supported by the Machine Learning Applied to Networks and Practical Aspects of Evolutionary Algorithms tracks, providing surveys on new application areas, as in the networking area and useful insights in the development of evolutionary techniques, from a practitioner’s perspective. Complementary to these directions, the conference tracks supporting the volume, follow on the individual advancements of the subareas constituting the scope of the confe...

  17. Evolvable Neural Software System

    Science.gov (United States)

    Curtis, Steven A.

    2009-01-01

    The Evolvable Neural Software System (ENSS) is composed of sets of Neural Basis Functions (NBFs), which can be totally autonomously created and removed according to the changing needs and requirements of the software system. The resulting structure is both hierarchical and self-similar in that a given set of NBFs may have a ruler NBF, which in turn communicates with other sets of NBFs. These sets of NBFs may function as nodes to a ruler node, which are also NBF constructs. In this manner, the synthetic neural system can exhibit the complexity, three-dimensional connectivity, and adaptability of biological neural systems. An added advantage of ENSS over a natural neural system is its ability to modify its core genetic code in response to environmental changes as reflected in needs and requirements. The neural system is fully adaptive and evolvable and is trainable before release. It continues to rewire itself while on the job. The NBF is a unique, bilevel intelligence neural system composed of a higher-level heuristic neural system (HNS) and a lower-level, autonomic neural system (ANS). Taken together, the HNS and the ANS give each NBF the complete capabilities of a biological neural system to match sensory inputs to actions. Another feature of the NBF is the Evolvable Neural Interface (ENI), which links the HNS and ANS. The ENI solves the interface problem between these two systems by actively adapting and evolving from a primitive initial state (a Neural Thread) to a complicated, operational ENI and successfully adapting to a training sequence of sensory input. This simulates the adaptation of a biological neural system in a developmental phase. Within the greater multi-NBF and multi-node ENSS, self-similar ENI s provide the basis for inter-NBF and inter-node connectivity.

  18. Reduced incidence of cardiac arrhythmias in walkers and runners.

    Science.gov (United States)

    Williams, Paul T; Franklin, Barry A

    2013-01-01

    Walking is purported to reduce the risk of atrial fibrillation by 48%, whereas jogging is purported to increase its risk by 53%, suggesting a strong anti-arrhythmic benefit of walking over running. The purpose of these analyses is to compare incident self-reported physician-diagnosed cardiac arrhythmia to baseline energy expenditure (metabolic equivalent hours per day, METhr/d) from walking, running and other exercise. Proportional hazards analysis of 14,734 walkers and 32,073 runners. There were 1,060 incident cardiac arrhythmias (412 walkers, 648 runners) during 6.2 years of follow-up. The risk for incident cardiac arrhythmias declined 4.4% per baseline METhr/d walked by the walkers, or running in the runners (P = 0.0001). Specifically, the risk declined 14.2% (hazard ratio: 0.858) for 1.8 to 3.6 METhr/d, 26.5% for 3.6 to 5.4 METhr/d, and 31.7% for ≥5.4 METhr/d, relative to cardiac arrhythmias. Cardiac arrhythmias were unrelated to walking and running intensity, and unrelated to marathon participation and performance. The risk for cardiac arrhythmias was similar in walkers and runners who expended comparable METhr/d during structured exercise. We found no significant risk increase for self-reported cardiac arrhythmias associated with running distance, exercise intensity, or marathon participation. Rhythm abnormalities were based on self-report, precluding definitive categorization of the nature of the rhythm disturbance. However, even if the runners' arrhythmias include sinus bradycardia due to running itself, there was no increase in arrhythmias with greater running distance.

  19. Host plants of Chrysodeixis includens (Walker (Lepidoptera, Noctuidae, Plusiinae

    Directory of Open Access Journals (Sweden)

    Alexandre Specht

    2015-12-01

    Full Text Available ABSTRACT This work has the objective to catalogue the information of Chrysodeixis includens (Walker, [1858] (Lepidoptera: Noctuidae: Plusiinae host plants. The list of plants comprehends new reports of host plants in Brazil and information from literature review around the world. It is listed 174 plants which are from 39 botanic families. The higher number of host plants of C. includens are in Asteraceae (29, Solanaceae (21, Fabaceae (18 and Lamiaceae (12.

  20. Host plants of Chrysodeixis includens (Walker) (Lepidoptera, Noctuidae, Plusiinae)

    OpenAIRE

    Specht, Alexandre; Paula-Moraes, Silvana Vieira de; Sosa-Gómez,Daniel Ricardo

    2015-01-01

    ABSTRACT This work has the objective to catalogue the information of Chrysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae: Plusiinae) host plants. The list of plants comprehends new reports of host plants in Brazil and information from literature review around the world. It is listed 174 plants which are from 39 botanic families. The higher number of host plants of C. includens are in Asteraceae (29), Solanaceae (21), Fabaceae (18) and Lamiaceae (12).

  1. Cochlear implantation in patient with Dandy-walker syndrome.

    Science.gov (United States)

    de Oliveira, Adriana Kosma Pires; Hamerschmidt, Rogerio; Mocelin, Marcos; Rezende, Rodrigo K

    2012-07-01

     Dandy Walker Syndrome is a congenital abnormality in the central nervous system, characterized by a deficiency in the development of middle cerebelar structures, cystic dilatation of the posterior pit communicating with the fourth ventricle and upward shift of the transverse sinuses, tentorium and dyes. Among the clinical signs are occipital protuberances, a progressive increase of the skull, bowing before the fontanels, papilledema, ataxia, gait disturbances, nystagmus, and intellectual impairment.  To describe a case of female patient, 13 years old with a diagnosis of this syndrome and bilateral hearing loss underwent cochlear implant surgery under local anesthesia and sedation.  CGS, 13 years old female was referred to the Otolaryngological Department of Otolaryngology Institute of Parana with a diagnosis of "Dandy-Walker syndrome" for Otolaryngological evaluation for bilateral hearing loss with no response to the use of hearing aids. Final Comments: The field of cochlear implants is growing rapidly. We believe that the presence of Dandy-Walker syndrome cannot be considered a contraindication to the performance of cochlear implant surgery, and there were no surgical complications due to neurological disorders with very favorable results for the patient who exhibits excellent discrimination. It has less need for lip reading with improvement in speech quality.

  2. Cochlear implantation in patient with Dandy-walker syndrome

    Directory of Open Access Journals (Sweden)

    Oliveira, Adriana Kosma Pires de

    2012-01-01

    Full Text Available Introduction: Dandy Walker Syndrome is a congenital abnormality in the central nervous system, characterized by a deficiency in the development of middle cerebelar structures, cystic dilatation of the posterior pit communicating with the fourth ventricle and upward shift of the transverse sinuses, tentorium and dyes. Among the clinical signs are occipital protuberances, a progressive increase of the skull, bowing before the fontanels, papilledema, ataxia, gait disturbances, nystagmus, and intellectual impairment. Objectives: To describe a case of female patient, 13 years old with a diagnosis of this syndrome and bilateral hearing loss underwent cochlear implant surgery under local anesthesia and sedation. Case Report: CGS, 13 years old female was referred to the Otolaryngological Department of Otolaryngology Institute of Parana with a diagnosis of "Dandy-Walker syndrome" for Otolaryngological evaluation for bilateral hearing loss with no response to the use of hearing aids. Final Comments: The field of cochlear implants is growing rapidly. We believe that the presence of Dandy-Walker syndrome cannot be considered a contraindication to the performance of cochlear implant surgery, and there were no surgical complications due to neurological disorders with very favorable results for the patient who exhibits excellent discrimination. It has less need for lip reading with improvement in speech quality.

  3. Regolith Evolved Gas Analyzer

    Science.gov (United States)

    Hoffman, John H.; Hedgecock, Jud; Nienaber, Terry; Cooper, Bonnie; Allen, Carlton; Ming, Doug

    2000-01-01

    The Regolith Evolved Gas Analyzer (REGA) is a high-temperature furnace and mass spectrometer instrument for determining the mineralogical composition and reactivity of soil samples. REGA provides key mineralogical and reactivity data that is needed to understand the soil chemistry of an asteroid, which then aids in determining in-situ which materials should be selected for return to earth. REGA is capable of conducting a number of direct soil measurements that are unique to this instrument. These experimental measurements include: (1) Mass spectrum analysis of evolved gases from soil samples as they are heated from ambient temperature to 900 C; and (2) Identification of liberated chemicals, e.g., water, oxygen, sulfur, chlorine, and fluorine. REGA would be placed on the surface of a near earth asteroid. It is an autonomous instrument that is controlled from earth but does the analysis of regolith materials automatically. The REGA instrument consists of four primary components: (1) a flight-proven mass spectrometer, (2) a high-temperature furnace, (3) a soil handling system, and (4) a microcontroller. An external arm containing a scoop or drill gathers regolith samples. A sample is placed in the inlet orifice where the finest-grained particles are sifted into a metering volume and subsequently moved into a crucible. A movable arm then places the crucible in the furnace. The furnace is closed, thereby sealing the inner volume to collect the evolved gases for analysis. Owing to the very low g forces on an asteroid compared to Mars or the moon, the sample must be moved from inlet to crucible by mechanical means rather than by gravity. As the soil sample is heated through a programmed pattern, the gases evolved at each temperature are passed through a transfer tube to the mass spectrometer for analysis and identification. Return data from the instrument will lead to new insights and discoveries including: (1) Identification of the molecular masses of all of the gases

  4. Walker-assisted gait in rehabilitation: a study of biomechanics and instrumentation.

    Science.gov (United States)

    Bachschmidt, R A; Harris, G F; Simoneau, G G

    2001-03-01

    While walkers are commonly prescribed to improve patient stability and ambulatory ability, quantitative study of the biomechanical and functional requirements for effective walker use is limited. To date no one has addressed the changes in upper extremity kinetics that occur with the use of a standard walker, which was the objective of this study. A strain gauge-based walker instrumentation system was developed for the six degree-of-freedom measurement of resultant subject hand loads. The walker dynamometer was integrated with an upper extremity biomechanical model. Preliminary system data were collected for seven healthy, right-handed young adults following informed consent. Bilateral upper extremity kinematic data were acquired with a six camera Vicon motion analysis system using a Micro-VAX workstation. Internal joint moments at the wrist, elbow, and shoulder were determined in the three clinical planes using the inverse dynamics method. The walker dynamometer system allowed characterization of upper extremity loading demands. Significantly differing upper extremity loading patterns were identified for three walker usage methods. Complete description of upper extremity kinetics and kinematics during walker-assisted gait may provide insight into walker design parameters and rehabilitative strategies.

  5. Mechanical-Kinetic Modeling of a Molecular Walker from a Modular Design Principle

    Science.gov (United States)

    Hou, Ruizheng; Loh, Iong Ying; Li, Hongrong; Wang, Zhisong

    2017-02-01

    Artificial molecular walkers beyond burnt-bridge designs are complex nanomachines that potentially replicate biological walkers in mechanisms and functionalities. Improving the man-made walkers up to performance for widespread applications remains difficult, largely because their biomimetic design principles involve entangled kinetic and mechanical effects to complicate the link between a walker's construction and ultimate performance. Here, a synergic mechanical-kinetic model is developed for a recently reported DNA bipedal walker, which is based on a modular design principle, potentially enabling many directional walkers driven by a length-switching engine. The model reproduces the experimental data of the walker, and identifies its performance-limiting factors. The model also captures features common to the underlying design principle, including counterintuitive performance-construction relations that are explained by detailed balance, entropy production, and bias cancellation. While indicating a low directional fidelity for the present walker, the model suggests the possibility of improving the fidelity above 90% by a more powerful engine, which may be an improved version of the present engine or an entirely new engine motif, thanks to the flexible design principle. The model is readily adaptable to aid these experimental developments towards high-performance molecular walkers.

  6. Primordial evolvability: Impasses and challenges.

    Science.gov (United States)

    Vasas, Vera; Fernando, Chrisantha; Szilágyi, András; Zachár, István; Santos, Mauro; Szathmáry, Eörs

    2015-09-21

    While it is generally agreed that some kind of replicating non-living compounds were the precursors of life, there is much debate over their possible chemical nature. Metabolism-first approaches propose that mutually catalytic sets of simple organic molecules could be capable of self-replication and rudimentary chemical evolution. In particular, the graded autocatalysis replication domain (GARD) model, depicting assemblies of amphiphilic molecules, has received considerable interest. The system propagates compositional information across generations and is suggested to be a target of natural selection. However, evolutionary simulations indicate that the system lacks selectability (i.e. selection has negligible effect on the equilibrium concentrations). We elaborate on the lessons learnt from the example of the GARD model and, more widely, on the issue of evolvability, and discuss the implications for similar metabolism-first scenarios. We found that simple incorporation-type chemistry based on non-covalent bonds, as assumed in GARD, is unlikely to result in alternative autocatalytic cycles when catalytic interactions are randomly distributed. An even more serious problem stems from the lognormal distribution of catalytic factors, causing inherent kinetic instability of such loops, due to the dominance of efficiently catalyzed components that fail to return catalytic aid. Accordingly, the dynamics of the GARD model is dominated by strongly catalytic, but not auto-catalytic, molecules. Without effective autocatalysis, stable hereditary propagation is not possible. Many repetitions and different scaling of the model come to no rescue. Despite all attempts to show the contrary, the GARD model is not evolvable, in contrast to reflexively autocatalytic networks, complemented by rare uncatalyzed reactions and compartmentation. The latter networks, resting on the creation and breakage of chemical bonds, can generate novel ('mutant') autocatalytic loops from a given set of

  7. On the Instabilities of the Walker Propagating Domain Wall Solution

    OpenAIRE

    Hu, Bin; Wang, Xiangrong

    2013-01-01

    A powerful mathematical method for front instability analysis that was recently developed in the field of nonlinear dynamics is applied to the 1+1 (spatial and time) dimensional Landau-Lifshitz-Gilbert (LLG) equation. From the essential spectrum of the LLG equation, it is shown that the famous Walker rigid body propagating domain wall (DW) is not stable against the spin wave emission. In the low field region only stern spin waves are emitted while both stern and bow waves are generated under ...

  8. Gravitational birefringence of light in Robertson-Walker cosmologies

    Science.gov (United States)

    Duval, C.; Schücker, T.

    2017-08-01

    The spacetime evolution of massless spinning particles in a Robertson-Walker background is derived using the deterministic system of equations of motion from Papapetrou, Souriau and Saturnini. A numerical integration of this system of differential equations in the case of the standard model of cosmology is performed. The deviation of the photon worldlines from the null geodesics is of the order of the wavelength. Perturbative solutions are also worked out in a more general case. An experimental measurement of this deviation would test the acceleration of our expanding Universe.

  9. Difficulties with Prenatal Diagnosis of the Walker-Warburg Syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Low, A.S.C.; Lee, S.L.; Tan, A.S.A.; Chan, D.K.L.; Chan, L.L. [Singapore General Hospital (Singapore). Depts. of Diagnostic Radiology, Obstetrics and Gynecology and Neonatology

    2005-10-01

    We describe a postnatally diagnosed case of Walker-Warburg syndrome - a form of congenital muscular dystrophy with lissencephaly and eye abnormalities. We reviewed the literature to highlight its clinico-radiological diagnostic features and discuss the difficulties encountered with prenatal diagnosis, especially in cases with no positive family history. An increased awareness of this rare but lethal condition, and a high index of suspicion during routine antenatal ultrasound, could prompt further advanced fetal ultrasonography and magnetic resonance imaging, and aid in timely prenatal diagnosis, management, and counseling. Brain/brainstem, congenital, magnetic resonance imaging, obstetrics, pediatrics, ultrasound.

  10. Constructive solution of the robotic chassis AnyWalker

    Directory of Open Access Journals (Sweden)

    Riadchykov Igor

    2016-01-01

    Full Text Available Presented constructive solution of the robotic system effectively solves the problem of movement in human-adapted not pre-prepared environment. AnyWalker stabilization system consists of three flywheels, implemented in the form of motor-wheels or driven with the help of transfer mechanisms each from its motor, in orthogonal planes, and the centers of mass flywheels are the same. It is proposed to formalize the functionality of the movement in the human-adapted environment in the form of a standard architecture for robotic chassis with the possibility of hardware and software extension.

  11. A newborn with neurocutaneous melanocytosis and Dandy-Walker malformation.

    Science.gov (United States)

    De Cock, Jens; Snauwaert, Julie; Van Rompaey, Walter; Morren, Marie-Anne; Demaerel, Philippe

    2014-03-01

    Neurocutaneous melanocytosis is a rare congenital dysplasia of the neuroectodermal melanocyte precursor cells that leads to proliferation of melanin-producing cells in the skin and leptomeninges. We describe a newborn with a giant congenital melanocytic nevus on his back, buttocks, and thighs. His brain magnetic resonance imaging study revealed bilateral T1 hyperintense lesions in the cerebellum and in the amygdala, hydrocephalus, and a Blake's pouch cyst, consistent with neurocutaneous melanocytosis and Dandy-Walker malformation. Neurocutaneous melanocytosis has a wide clinical spectrum that includes hydrocephalus, epilepsy, cranial nerve palsy, increased intracranial pressure, and sensorimotor deficits. Copyright © 2014. Published by Elsevier Inc.

  12. Atypical psychotic symptoms and Dandy-Walker variant.

    Science.gov (United States)

    Williams, Aislinn J; Wang, Zhenni; Taylor, Stephan F

    2016-10-01

    New-onset psychotic symptoms often respond well to antipsychotic treatment; however, symptoms may be difficult to treat when an underlying brain malformation is present. Here, we present a case of atypical psychotic symptoms in the context of a congenital cerebellar malformation (Dandy-Walker variant). The patient ultimately improved with paliperidone palmitate after multiple antipsychotic medication trials (both oral and one long-acting injectable) were ineffective. Neuroimaging may provide valuable diagnostic and prognostic information in cases of new-onset psychosis with atypical features and treatment resistance, even in the absence of neurologic signs and symptoms.

  13. Dispersion, Topological Scattering, and Self-Interference in Multiply Connected Robertson-Walker Cosmologies

    CERN Document Server

    Tomaschitz, R

    1994-01-01

    We investigate scattering effects in open Robertson-Walker cosmologies whose spacelike slices are multiply connected hyperbolic manifolds. We work out an example in which the 3-space is infinite and has the topology of a solid torus. The world-lines in these cosmologies are unstable, and classical probability densities evolving under the horospherical geodesic flow show dispersion, as do the densities of scalar wave packets. The rate of dispersion depends crucially on the expansion factor, and we calculate the time evolution of their widths. We find that the cosmic expansion can confine dispersion: The diameter of the domain of chaoticity in the 3-manifold provides the natural, time-dependent length unit in an infinite, multiply connected universe. In a toroidal 3-space manifold this diameter is just the length of the limit cycle. On this scale we find that the densities take a finite limit width in the late stage of the expansion. In the early stage classical densities and conformally coupled fields approach...

  14. Fat: an evolving issue

    Directory of Open Access Journals (Sweden)

    John R. Speakman

    2012-09-01

    Work on obesity is evolving, and obesity is a consequence of our evolutionary history. In the space of 50 years, we have become an obese species. The reasons why can be addressed at a number of different levels. These include separating between whether the primary cause lies on the food intake or energy expenditure side of the energy balance equation, and determining how genetic and environmental effects contribute to weight variation between individuals. Opinion on whether increased food intake or decreased energy expenditure drives the obesity epidemic is still divided, but recent evidence favours the idea that food intake, rather than altered expenditure, is most important. There is more of a consensus that genetics explains most (probably around 65% of weight variation between individuals. Recent advances in genome-wide association studies have identified many polymorphisms that are linked to obesity, yet much of the genetic variance remains unexplained. Finding the causes of this unexplained variation will be an impetus of genetic and epigenetic research on obesity over the next decade. Many environmental factors – including gut microbiota, stress and endocrine disruptors – have been linked to the risk of developing obesity. A better understanding of gene-by-environment interactions will also be key to understanding obesity in the years to come.

  15. Evolving Concepts of Asthma

    Science.gov (United States)

    Ray, Anuradha; Wenzel, Sally E.

    2015-01-01

    Our understanding of asthma has evolved over time from a singular disease to a complex of various phenotypes, with varied natural histories, physiologies, and responses to treatment. Early therapies treated most patients with asthma similarly, with bronchodilators and corticosteroids, but these therapies had varying degrees of success. Similarly, despite initial studies that identified an underlying type 2 inflammation in the airways of patients with asthma, biologic therapies targeted toward these type 2 pathways were unsuccessful in all patients. These observations led to increased interest in phenotyping asthma. Clinical approaches, both biased and later unbiased/statistical approaches to large asthma patient cohorts, identified a variety of patient characteristics, but they also consistently identified the importance of age of onset of disease and the presence of eosinophils in determining clinically relevant phenotypes. These paralleled molecular approaches to phenotyping that developed an understanding that not all patients share a type 2 inflammatory pattern. Using biomarkers to select patients with type 2 inflammation, repeated trials of biologics directed toward type 2 cytokine pathways saw newfound success, confirming the importance of phenotyping in asthma. Further research is needed to clarify additional clinical and molecular phenotypes, validate predictive biomarkers, and identify new areas for possible interventions. PMID:26161792

  16. Evolving endoscopic surgery.

    Science.gov (United States)

    Sakai, Paulo; Faintuch, Joel

    2014-06-01

    Since the days of Albukasim in medieval Spain, natural orifices have been regarded not only as a rather repugnant source of bodily odors, fluids and excreta, but also as a convenient invitation to explore and treat the inner passages of the organism. However, surgical ingenuity needed to be matched by appropriate tools and devices. Lack of technologically advanced instrumentation was a strong deterrent during almost a millennium until recent decades when a quantum jump materialized. Endoscopic surgery is currently a vibrant and growing subspecialty, which successfully handles millions of patients every year. Additional opportunities lie ahead which might benefit millions more, however, requiring even more sophisticated apparatuses, particularly in the field of robotics, artificial intelligence, and tissue repair (surgical suturing). This is a particularly exciting and worthwhile challenge, namely of larger and safer endoscopic interventions, followed by seamless and scarless recovery. In synthesis, the future is widely open for those who use together intelligence and creativity to develop new prototypes, new accessories and new techniques. Yet there are many challenges in the path of endoscopic surgery. In this new era of robotic endoscopy, one will likely need a virtual simulator to train and assess the performance of younger doctors. More evidence will be essential in multiple evolving fields, particularly to elucidate whether more ambitious and complex pathways, such as intrathoracic and intraperitoneal surgery via natural orifice transluminal endoscopic surgery (NOTES), are superior or not to conventional techniques. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

  17. Evolving a photosynthetic organelle

    Directory of Open Access Journals (Sweden)

    Nakayama Takuro

    2012-04-01

    Full Text Available Abstract The evolution of plastids from cyanobacteria is believed to represent a singularity in the history of life. The enigmatic amoeba Paulinella and its 'recently' acquired photosynthetic inclusions provide a fascinating system through which to gain fresh insight into how endosymbionts become organelles. The plastids, or chloroplasts, of algae and plants evolved from cyanobacteria by endosymbiosis. This landmark event conferred on eukaryotes the benefits of photosynthesis - the conversion of solar energy into chemical energy - and in so doing had a huge impact on the course of evolution and the climate of Earth 1. From the present state of plastids, however, it is difficult to trace the evolutionary steps involved in this momentous development, because all modern-day plastids have fully integrated into their hosts. Paulinella chromatophora is a unicellular eukaryote that bears photosynthetic entities called chromatophores that are derived from cyanobacteria and has thus received much attention as a possible example of an organism in the early stages of organellogenesis. Recent studies have unlocked the genomic secrets of its chromatophore 23 and provided concrete evidence that the Paulinella chromatophore is a bona fide photosynthetic organelle 4. The question is how Paulinella can help us to understand the process by which an endosymbiont is converted into an organelle.

  18. SYMMETRY AS CONCEPTUAL METAPHOR IN WALKER'S THE COLOR PURPLE

    Directory of Open Access Journals (Sweden)

    Elena Tapia

    2003-05-01

    Full Text Available The author analyzes three types of the conceptual metaphor of embodied symmetry in Alice Walker's novel, The color purple (1982. These metaphorical projections, perceived as equilibrium and its breakage in abstract phenomena, enable readers to reexamine issues of race, non-traditional families, and gender roles. The dis/equilibrium emerges in the novel's epistolary structure. Biological equilibrium breaks in incidents of rape and incest. Walker creates characters in the novel through default-concept opposites of black/white, submissive/dominant, male/female and others. These contraries foreground issues of race and gender. The novel's asymmetries engage readers, leading them to rethink individual character histories and motives. The removal of objects (e.g., rape, mothers deprived of children suggests conceptual asymmetry and alerts readers to parallel themes of sexual and racial oppression. Subjugation sometimes subtle, sometimes blatant- manifests in simple oppositions. In epistemological terms, readers seek causal explanations for the asymmetries of the narrative, interpreting each to recover its history.

  19. FreeWalker: a smart insole for longitudinal gait analysis.

    Science.gov (United States)

    Wang, Baitong; Rajput, Kuldeep Singh; Tam, Wing-Kin; Tung, Anthony K H; Yang, Zhi

    2015-08-01

    Gait analysis is an important diagnostic measure to investigate the pattern of walking. Traditional gait analysis is generally carried out in a gait lab, with equipped force and body tracking sensors, which needs a trained medical professional to interpret the results. This procedure is tedious, expensive, and unreliable and makes it difficult to track the progress across multiple visits. In this paper, we present a smart insole called FreeWalker, which provides quantitative gait analysis outside the confinement of traditional lab, at low- cost. The insole consists of eight pressure sensors and two motion tracking sensors, i.e. 3-axis accelerometer and 3-axis gyroscope. This enables measurement of under-foot pressure distribution and motion sequences in real-time. The insole is enabled with onboard SD card as well as wireless data transmission, which help in continuous gait-cycle analysis. The data is then sent to a gateway, for analysis and interpretation of data, using a user interface where gait features are graphically displayed. We also present validation result of a subject's left foot, who was asked to perform a specific task. Experiment results show that we could achieve a data-sampling rate of over 1 KHz, transmitting data up to a distance of 20 meter and maintain a battery life of around 24 hours. Taking advantage of these features, FreeWalker can be used in various applications, like medical diagnosis, rehabilitation, sports and entertainment.

  20. Neuroimaging of Dandy-Walker malformation: new concepts.

    Science.gov (United States)

    Correa, Gustavo Gumz; Amaral, Lázaro Faria; Vedolin, Leonardo Modesti

    2011-12-01

    Dandy-Walker malformation (DWM) is the most common human cerebellar malformation, characterized by hypoplasia of the cerebellar vermis, cystic dilation of the fourth ventricle, and an enlarged posterior fossa with upward displacement of the lateral sinuses, tentorium, and torcular. Although its pathogenesis is not completely understood, there are several genetic loci related to DWM as well as syndromic malformations and congenital infections. Dandy-Walker malformation is associated with other central nervous system abnormalities, including dysgenesis of corpus callosum, ectopic brain tissue, holoprosencephaly, and neural tube defects. Hydrocephalus plays an important role in the development of symptoms and neurological outcome in patients with DWM, and the aim of surgical treatment is usually the control of hydrocephalus and the posterior fossa cyst. Imaging modalities, especially magnetic resonance imaging, are crucial for the diagnosis of DWM and distinguishing this disorder from other cystic posterior fossa lesions. Persistent Blake's cyst is seen as a retrocerebellar fluid collection with cerebrospinal fluid signal intensity and a median line communication with the fourth ventricle, commonly associated with hydrocephalus. Mega cisterna magna presents as an extraaxial fluid collection posteroinferior to an intact cerebellum. Retrocerebellar arachnoid cysts frequently compress the cerebellar hemispheres and the fourth ventricle. Patients with DWM show an enlarged posterior fossa filled with a cystic structure that communicates freely with the fourth ventricle and hypoplastic vermis. Comprehension of hindbrain embryology is of utmost importance for understanding the cerebellar malformations, including DWM, and other related entities.

  1. Vertical force and wrist deviation angle when using a walker to stand up and sit down.

    Science.gov (United States)

    Leung, Cherng-Yee; Yeh, Po-Chan

    2011-08-01

    Research investigating walkers suggests that safety and assistance for the elderly with weak lower limbs were important. However, the relationship between the use of a walker and the upper limbs has received little investigation. Standing up and sitting down are important daily activities. Therefore, the aim of this study was to explore wrist deviation and vertical force among elderly individuals using a walker for assistance to stand up and sit down. In total, 64 elderly volunteers (M age = 80.22, SD = 9.36) were enrolled. Data were obtained from four load cells and a twin-axis wrist goniometer. Wrist deviation and vertical force were examined when participants used a walker with horizontal handles to assist in standing up and sitting down. Significant wrist angle deviation occurred with the use of a walker, with dorsiflexion of the right hand greater than that of the left. Males exerted significantly greater vertical force. In the sitting position, greater ulnar deviation was seen among experienced walker users, whereas during standing, experienced users exhibited greater dorsiflexion. The horizontal handles of most marketed walkers may cause user wrist deviations, suggesting researchers should pursue improvements in walker design.

  2. Dandy-Walker sendromlu çocuk hastada anestezi yönetimi

    OpenAIRE

    Çelik, Feyzi; Tüfek, Adnan; Temel, Vildan; Akdemir, Salim; Yıldırım, Zeynep Baysal; Kavak, Gönül Ölmez

    2011-01-01

    General anesthesia management of patients with Dandy-Walker syndrome is important since intubation may be difficult due to concomitant anomalies such as hydrocephalus, micrognathia and cleft palate. It should be considered that these patients may require postoperative intensive care support. In this article, anesthesia management of a patient with Dandy-Walker syndrome underwent persistent ventriculo-peritoneal shunt was presented.

  3. The Role of Walkers? Needs and Expectations in Supporting Maintenance of Attendance at Walking Groups: A Longitudinal Multi-Perspective Study of Walkers and Walk Group Leaders

    OpenAIRE

    Aikaterini Kassavou; Andrew Turner; French, David P.

    2015-01-01

    Background There is good evidence that when people?s needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers? nee...

  4. Impact of strut height on offloading capacity of removable cast walkers.

    Science.gov (United States)

    Crews, Ryan T; Sayeed, Fraaz; Najafi, Bijan

    2012-08-01

    Reducing weight-bearing stress to diabetic foot ulcers is critical to healing and commonly called offloading. Removable cast walkers are frequently used for offloading; however, patient compliance is often poor. Walkers commonly extend to the knee. Patients complain about walkers' weight and diminished balance with their use. This study compared the offloading capacity of walkers that varied by height. Heights included: knee, ankle, and shoe levels. To ensure a fair comparison the outsole and insole were standardized across the devices. Eleven diabetic subjects with moderate to high risk of ulceration were recruited. Subjects completed four 20 m walking trials. Subjects performed one trial with each walker and one trial with an athletic shoe. Primary outcomes focused on plantar loading and were measured by pressure insoles. Secondary outcomes were associated with gait kinematics as collected by body worn sensors. Significant differences were found for the peak pressure and pressure time integrals of the different footwear. All walkers performed better than the athletic shoe. The ankle and knee-high devices performed best. Center of mass rotation data showed a trend of the ankle walker yielding a smaller range of motion (18% medial/lateral and 22% anterior/posterior) than the knee level. The ankle-high walker was able to provide similar offloading capacities as the knee-high walker. The diminished weight, along with potentially improved stability, may result in improved compliance with ankle-high walkers. A study comparing the use of the two devices for treating ulcers is now suggested. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Walker-Warburg syndrome: report of two cases

    Directory of Open Access Journals (Sweden)

    VASCONCELOS MARCIO M.

    1999-01-01

    Full Text Available The purpose of this study is to describe two infants that were diagnosed with Walker-Warburg syndrome (WWS, a rare form of congenital muscular dystrophy (CMD.They were studied in their clinical, laboratory, and neuroradiologic features. The index case had a brain magnetic resonance imaging (MRI and the second patient had a head computerized tomography (CT. In addition, a literature review was performed to describe the main forms of CMD. The index case fulfilled all criteria for WWS. A brain MRI performed at age 4 months served to corroborate the clinical diagnosis, showing severe hydrocephalus, type II lissencephaly, cerebellar vermian aplasia, and a hypoplastic brain stem. The authors were able to establish a retrospective diagnosis of WWS in the index case's older sister, based upon her clinical picture and head CT report.

  6. Electromagnetic Radiation in Multiply Connected Robertson-Walker Cosmologies

    CERN Document Server

    Tomaschitz, R

    1993-01-01

    Maxwell's equations on a topologically nontrivial cosmological background are studied. The cosmology is locally determined by a Robertson-Walker line element, but the spacelike slices are open hyperbolic manifolds, whose topology and geometry may vary in time. In this context the spectral resolution of Maxwell's equations in terms of horospherical elementary waves generated at infinity of hyperbolic space is given. The wave fronts are orthogonal to bundles of unstable geodesic rays, and the eikonal of geometric optics appears just as the phase of the horospherical waves. This fact is used to attach to the unstable geodesic rays a quantum mechanical momentum. In doing so the quantized energy-momentum tensor of the radiation field is constructed in a geometrically and dynamically transparent way, without appealing to the intricacies of the second quantization. In particular Planck's radiation formula, and the bearing of the multiply connected topology on the fluctuations in the temperature of the background rad...

  7. A Newborn with Dandy-Walker Malformation and Aortic Coarctation

    Directory of Open Access Journals (Sweden)

    Ayşe Anık

    2017-11-01

    Full Text Available Dandy-Walker malformation (DWM is a rare anomaly of the posterior cranial fossa. Concomitant brain or systemic malformations are frequent and can influence the prognosis. DWM is associated with cardiac abnormalities. Recognition of these anomalies are important for diagnosis and accurate surgical management. Association of aortic coarctation with DWM is extremely rare. Here, we report a newborn with DWM and aortic coarctation. Our aim was to emphasize that DWM can be associated with cardiac anomalies. Cardiac congenital defects are often associated with a poor prognosis. These kinds of features should alert the clinician to consider extensive screening in these patients not only for cerebral structures but also for cardiovascular abnormalities.

  8. Field diet of the grasshopper Abracris dilecta Walker (Orthoptera, Acrididae

    Directory of Open Access Journals (Sweden)

    Carlos Frankl Sperber

    1996-01-01

    Full Text Available Abracris dilecta Walker, 1870 (Orthoptera, Acrididae, Ommatolampinae ate leafs of at least 14 plant species, in the families Asteraceae, Lamiaceae, Malvales (Sterculiaceae, Tiliaceae or Malvaceae, Poaceae, Fabaceae, Verbenaceae, Aristolochiaceae, Rubiaceae and Melastomataccae. Elephantopus mollis H.B.K. (Asteraceae and Hyptis suaveolens Poit. (Lamiaceae comprised 50% of the diet. The diet breadth of A. dilecta was compared to that of other 11 grasshopper species of the same sub-family, with rarefaction curves. The number of plant species eaten by A. dilecta was greater than that of nine other grasshopper species of the same sub-family (Rhachicreagra spp. but was lower then two others (Microptylopteryx hebardi Rehn, 1905 and Rhachicreagra astytophallus Jago & Rowell, 1981. This results are discussed in view of the broad geographical range and possession of developed wings by A. dilecta, which contrasts with most Ommatolampinae grasshoppers.

  9. [Aicardi syndrome with Dandy-Walker type malformation].

    Science.gov (United States)

    Laguado-Herrera, Yuly V; Manrique-Hernández, Edgar F; Peñaloza-Mantilla, Camilo A; Quintero-Gómez, David A; Contreras-García, Gustavo A; Sandoval-Martínez, Diana K

    2015-07-16

    Aicardi syndrome (OMIM 304050) was first described in 1965. Its classic triad consists of infantile spasms, partial or total agenesis of the corpus callosum and ocular disorders, such as chorioretinal lacunae. It has been posited that it is due to a mechanism involving X-linked dominant inheritance. We report the case of a full-term female, with no pathological familial history or parental consanguinity, with a prenatal diagnosis of Dandy-Walker type malformation, who presented convulsions, coloboma of the optic nerve, thoracic vertebral block with presence of scoliosis, transfontanellar ultrasound imaging showing agenesis of the corpus callosum and karyotype 46,XX. She was diagnosed with Aicardi syndrome and died at the age of one and a half months. The autopsy revealed supratentorial hydrocephalus with the presence of choroid plexus papilloma, a cyst in the posterior fossa (fourth ventricle), hypoplasia of the cerebellar vermis, agenesis of the left hemisphere of the corpus callosum and cerebellum, characteristic facial features of the syndrome, ogival palate, pectus excavatum, scoliosis, paraovarian cyst and hepatomegaly. Few cases of an association between the pathology and the presence of Dandy-Walker malformation have been described. We report a new case of the association, bearing in mind that the related disorders, mainly agenesis or hypoplasia of the corpus callosum, suggest the existence of an underlying genetic component. A study of the search for the aetiology must be focused on evaluating those genes that are related with neurodevelopment and its activation in the organogenesis stage. The definitive diagnosis establishes the prognosis, management and genetic counselling of the family.

  10. Natural selection promotes antigenic evolvability

    NARCIS (Netherlands)

    Graves, C.J.; Ros, V.I.D.; Stevenson, B.; Sniegowski, P.D.; Brisson, D.

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide

  11. Disgust: Evolved function and structure

    NARCIS (Netherlands)

    Tybur, J.M.; Lieberman, D.; Kurzban, R.; DeScioli, P.

    2013-01-01

    Interest in and research on disgust has surged over the past few decades. The field, however, still lacks a coherent theoretical framework for understanding the evolved function or functions of disgust. Here we present such a framework, emphasizing 2 levels of analysis: that of evolved function and

  12. [Upper extremity kinetics and energy expenditure during walker-assisted gait in children with cerebral palsy].

    Science.gov (United States)

    Konop, Katherine A; Strifling, Kelly M B; Wang, Mei; Cao, Kevin; Eastwood, Daniel; Jackson, Scott; Ackman, Jeffrey; Altiok, Haluk; Schwab, Jeffrey; Harris, Gerald F

    2009-01-01

    We evaluated the relationships between upper extremity (UE) kinetics and the energy expenditure index during anterior and posterior walker-assisted gait in children with spastic diplegic cerebral palsy (CP). Ten children (3 boys, 7 girls; mean age 12.1 years; range 8 to 18 years) with spastic diplegic CP, who ambulated with a walker underwent gait analyses that included UE kinematics and kinetics. Upper extremity kinetics were obtained using instrumented walker handles. Energy expenditure index was obtained using the heart rate method (EEIHR) by subtracting resting heart rate from walking heart rate, and dividing by the walking speed. Correlations were sought between the kinetic variables and the EEIHR and temporal and stride parameters. In general, anterior walker use was associated with a higher EEIHR. Several kinetic variables correlated well with temporal and stride parameters, as well as the EEIHR. All of the significant correlations (r>0.80; p<0.005) occurred during anterior walker use and involved joint reaction forces (JRF) rather than moments. Some variables showed multiple strong correlations during anterior walker use, including the medial JRF in the wrist, the posterior JRF in the elbow, and the inferior and superior JRFs in the shoulder. The observed correlations may indicate a relationship between the force used to advance the body forward within the walker frame and an increased EEIHR. More work is needed to refine the correlations, and to explore relationships with other variables, including the joint kinematics.

  13. Vertical force and wrist deviation angle in a sample of elderly people using walkers.

    Science.gov (United States)

    Leung, Cherng-Yee; Yeh, Po-Chan

    2013-02-01

    Walkers are frequently used by elderly people with weak lower limbs and limited balance, but the ergonomic relationship between the use of a walker and stress on the upper limbs is relatively unstudied. The current study assessed wrist deviation and vertical force among elderly individuals using a walker for assistance in walking. 60 elderly volunteers (M age = 81.0 yr., SD = 8.8) participated, 30 of whom frequently used a walker, and 30 who had no such prior experience. Data were obtained from four load cells and a twin-axis wrist goniometer during assisted ambulation using the walker. No significant group difference was found in gait cycle. Significant wrist deviation occurred, with ulnar deviation/dorsiflexion of the right hand, which was greater than that of the left. Non-experienced participants had larger dorsiflexion than experienced participants. Experienced participants produced larger vertical force than non-experienced participants. The greaterthe wrist deviation, the greater was the vertical force. The horizontal handles of most marketed walkers cause wrist deviations. This is a concern for users, clinicians, and related industries. Improvements in walker design should be considered.

  14. Assistive devices alter gait patterns in Parkinson disease: advantages of the four-wheeled walker.

    Science.gov (United States)

    Kegelmeyer, Deb A; Parthasarathy, Sowmya; Kostyk, Sandra K; White, Susan E; Kloos, Anne D

    2013-05-01

    Gait abnormalities are a hallmark of Parkinson's disease (PD) and contribute to fall risk. Therapy and exercise are often encouraged to increase mobility and decrease falls. As disease symptoms progress, assistive devices are often prescribed. There are no guidelines for choosing appropriate ambulatory devices. This unique study systematically examined the impact of a broad range of assistive devices on gait measures during walking in both a straight path and around obstacles in individuals with PD. Quantitative gait measures, including velocity, stride length, percent swing and double support time, and coefficients of variation were assessed in 27 individuals with PD with or without one of six different devices including canes, standard and wheeled walkers (two, four or U-Step). Data were collected using the GAITRite and on a figure-of-eight course. All devices, with the exception of four-wheeled and U-Step walkers significantly decreased gait velocity. The four-wheeled walker resulted in less variability in gait measures and had less impact on spontaneous unassisted gait patterns. The U-Step walker exhibited the highest variability across all parameters followed by the two-wheeled and standard walkers. Higher variability has been correlated with increased falls. Though subjects performed better on a figure-of-eight course using either the four-wheeled or the U-Step walker, the four-wheeled walker resulted in the most consistent improvement in overall gait variables. Laser light use on a U-Step walker did not improve gait measures or safety in figure-of-eight compared to other devices. Of the devices tested, the four-wheeled-walker offered the most consistent advantages for improving mobility and safety. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Metabolic memory: Evolving concepts.

    Science.gov (United States)

    Misra, Anoop; Bloomgarden, Zachary

    2018-03-01

    The relationships of glycemic control over time with the development of complications have been investigated in several studies, but new areas of debate continue to arise. Does glycemic control have greater benefit when attained earlier than when attained later in the natural history of diabetes? Is it simply the duration of better or worse levels of glycemia that lead a given individual to have fewer or greater levels of complications? Might glycemic control have similar benefit throughout the duration of diabetes until irreversible damage occurs, perhaps varying by organ system (neurologic, renal, retinal, cardiovascular)? Specific benefits or adverse effects of treatment agents may further complicate the interpretation of what has been characterized as "metabolic memory." The notion of metabolic memory was based on findings of the Diabetes Control and Complications Trial (DCCT) of type 1 diabetes (T1D), in which the initial 2% HbA1c separation between the groups of patients randomized to intensive or conventional control was lost during the follow up Epidemiology of Diabetes Interventions and Complications (EDIC) study, when the two groups of participants returned to standard treatment and showed similar HbA1c levels but the initial intensively treated group continued to have lower rates of development of microvascular and, subsequently, macrovascular complications. Similarly, a decade after the conclusion of the UK Prospective Diabetes Study (UKPDS), patients with type 2 diabetes (T2D) in the intensive therapy group, despite showing similar levels of glycemic control to those receiving standard care, continued to have significant reductions in microvascular endpoints and reductions in myocardial infarction and all-cause mortality. A 6-year follow up of the Veteran's Administration Diabetes Trial suggested that the formerly intensively controlled subset were more likely to maintain an estimated glomerular filtration rate >60 ml/min/1.73m 2 than those randomized

  16. Scoliosis in Dandy-Walker syndrome: a case report and review of literature.

    Science.gov (United States)

    Menon, Venugopal K; Sorur, Tamer M M; Al Ghafri, Khalifa A; Shahin, Marwan M H E

    2017-12-01

    This submission presents a case of scoliosis in a patient with established Dandy-Walker anomaly of the brain. A retrospective review of the patient's case notes was undertaken and the limited literature on this subject reviewed. The 13-year-old girl presented with a stiff right thoracic scoliosis typical of adolescent idiopathic scoliosis. The scoliotic segment also presented with significant lordosis. She had facial and truncal dysmorphism characteristic of Dandy-Walker complex and her brain images confirmed the diagnosis. She underwent scoliosis surgery by the posterior approach uneventfully. In conclusion scoliosis is hitherto unreported in the Dandy-Walker complex. The results of intervention appear satisfactory.

  17. Safe childbirth: Concept Analysis According to the Walker and Avant Method

    Directory of Open Access Journals (Sweden)

    Fernanda Maria Carvalho Fontenele

    2017-06-01

    Full Text Available Objective: This study analyzed the concept of "Safe delivery" using the method proposed by Walker and Avant, which establishes eight steps for the construction of a concept. Method: Literature search was carried out in the Virtual Health Library (VHL and the Scientific Electronic Library Online (Scielo in the period from April to July 2016. Controlled descriptors were: "Parturition", "Safety" and "Patient safety", in Portuguese and English.  The compound term "Safe Delivery" was also used.  Thirty two productions were included in this analysis. Results: Among the attributes, maternal and fetal monitoring stand out and, as antecedent, the identification of risks for preventing damage. The reduction of maternal and infant mortality and the well-being of the mother-child binomial were evident in this work. Following the establishment of model case and opposite case, the definition of safe delivery was obtained: "the set of care measures that seek to identify risks, prevent damage and/or complications during delivery, ensuring maternal and fetal monitoring in favor of the welfare of mother and child ". Conclusion: The analysis of the essential attributes, its antecedents and consequences made it possible to define the concept of safe delivery. However, it is considered that this concept is changeable bearing in mind that there is a lack of randomized studies to identify potential risks to childbirth.

  18. When did oxygenic photosynthesis evolve?

    National Research Council Canada - National Science Library

    Roger Buick

    2008-01-01

    ...2.4 Ga ago, but when the photosynthetic oxygen production began is debatable. However, geological and geochemical evidence from older sedimentary rocks indicates that oxygenic photosynthesis evolved well before this oxygenation event...

  19. Marshal: Maintaining Evolving Models Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SIFT proposes to design and develop the Marshal system, a mixed-initiative tool for maintaining task models over the course of evolving missions. Marshal-enabled...

  20. Natural selection promotes antigenic evolvability.

    Science.gov (United States)

    Graves, Christopher J; Ros, Vera I D; Stevenson, Brian; Sniegowski, Paul D; Brisson, Dustin

    2013-01-01

    The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios) and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish chronic infections.

  1. Natural selection promotes antigenic evolvability.

    Directory of Open Access Journals (Sweden)

    Christopher J Graves

    Full Text Available The hypothesis that evolvability - the capacity to evolve by natural selection - is itself the object of natural selection is highly intriguing but remains controversial due in large part to a paucity of direct experimental evidence. The antigenic variation mechanisms of microbial pathogens provide an experimentally tractable system to test whether natural selection has favored mechanisms that increase evolvability. Many antigenic variation systems consist of paralogous unexpressed 'cassettes' that recombine into an expression site to rapidly alter the expressed protein. Importantly, the magnitude of antigenic change is a function of the genetic diversity among the unexpressed cassettes. Thus, evidence that selection favors among-cassette diversity is direct evidence that natural selection promotes antigenic evolvability. We used the Lyme disease bacterium, Borrelia burgdorferi, as a model to test the prediction that natural selection favors amino acid diversity among unexpressed vls cassettes and thereby promotes evolvability in a primary surface antigen, VlsE. The hypothesis that diversity among vls cassettes is favored by natural selection was supported in each B. burgdorferi strain analyzed using both classical (dN/dS ratios and Bayesian population genetic analyses of genetic sequence data. This hypothesis was also supported by the conservation of highly mutable tandem-repeat structures across B. burgdorferi strains despite a near complete absence of sequence conservation. Diversification among vls cassettes due to natural selection and mutable repeat structures promotes long-term antigenic evolvability of VlsE. These findings provide a direct demonstration that molecular mechanisms that enhance evolvability of surface antigens are an evolutionary adaptation. The molecular evolutionary processes identified here can serve as a model for the evolution of antigenic evolvability in many pathogens which utilize similar strategies to establish

  2. POMT2 mutations cause alpha-dystroglycan hypoglycosylation and Walker-Warburg syndrome.

    NARCIS (Netherlands)

    Reeuwijk, J. van; Janssen, M.; Elzen, C. van der; Beltran Valero de Bernabe, D.; Sabatelli, P.; Merlini, L.; Boon, M.; Scheffer, H.; Brockington, M.; Muntoni, F.; Huynen, M.A.; Verrips, A.; Walsh, C.A.; Barth, P.G.; Brunner, H.G.; Bokhoven, J.H.L.M. van

    2005-01-01

    BACKGROUND: Walker-Warburg syndrome (WWS) is an autosomal recessive condition characterised by congenital muscular dystrophy, structural brain defects, and eye malformations. Typical brain abnormalities are hydrocephalus, lissencephaly, agenesis of the corpus callosum, fusion of the hemispheres,

  3. POMT2 mutations cause alpha-dystroglycan hypoglycosylation and Walker-Warburg syndrome

    NARCIS (Netherlands)

    van Reeuwijk, J.; Janssen, M.; van den Elzen, C.; Beltran-Valero de Bernabé, D.; Sabatelli, P.; Merlini, L.; Boon, M.; Scheffer, H.; Brockington, M.; Muntoni, F.; Huynen, M. A.; Verrips, A.; Walsh, C. A.; Barth, P. G.; Brunner, H. G.; van Bokhoven, H.

    2005-01-01

    Walker-Warburg syndrome (WWS) is an autosomal recessive condition characterised by congenital muscular dystrophy, structural brain defects, and eye malformations. Typical brain abnormalities are hydrocephalus, lissencephaly, agenesis of the corpus callosum, fusion of the hemispheres, cerebellar

  4. POMT2 mutations cause alpha-dystroglycan hypoglycosylation and Walker-Warburg syndrome

    NARCIS (Netherlands)

    van Reeuwijk, J; Janssen, M; van den Elzen, C; de Bernabe, DBV; Sabatelli, P; Merlini, L; Boon, M; Scheffer, H; Brockington, M; Muntoni, F; Huynen, MA; Verrips, A; Walsh, CA; Barth, PG; Brunner, HG; van Bokhoven, H

    2005-01-01

    Background: Walker-Warburg syndrome (WWS) is an autosomal recessive condition characterised by congenital muscular dystrophy, structural brain defects, and eye malformations. Typical brain abnormalities are hydrocephalus, lissencephaly, agenesis of the corpus callosum, fusion of the hemispheres,

  5. Mercury in biota and sediment in the Walker River Basin, Nevada and California

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Common loons (Gavia immer) that stage during migration at Walker Lake, Nevada, were found to have elevated concentrations of mercury in their blood. The source of...

  6. Investigating GAIM-GM’s Capability to Sense Ionospheric Irregularities via Walker Satellite Constellations

    Science.gov (United States)

    2015-03-26

    INVESTIGATING GAIM-GM’S CAPABILITY TO SENSE IONOSPHERIC IRREGULARITIES VIA WALKER SATELLITE CONSTELLATIONS THESIS Brandon T. McClung, Captain, USAF...CAPABILITY TO SENSE IONOSPHERIC IRREGULARITIES VIA WALKER SATELLITE CONSTELLATIONS THESIS Presented to the Faculty Department of Engineering Physics...APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENP-MS-15-M-076 INVESTIGATING GAIM-GM’S CAPABILITY TO SENSE IONOSPHERIC IRREGULARITIES VIA

  7. Usher syndrome associated with a variant of Dandy-Walker malformation.

    Science.gov (United States)

    Simsek, Tulay; Ozdamar, Yasemin; Simsek, Enver; Men, Gamze

    2010-05-21

    Three cases of Usher syndrome associated with a variant of Dandy-Walker malformation in three siblings from consanguineous Turkish parents are described. The siblings had retinitis pigmentosa and hearing loss. Two of the siblings also had mental retardation, which is not a constant finding in Usher syndrome. Dandy-Walker malformation might have contributed to the mental retardation in two of these patients and might be a coincidental finding with Usher syndrome. Copyright 2010, SLACK Incorporated.

  8. New-onset psychosis associated with dandy-walker variant in an adolescent female patient.

    Science.gov (United States)

    Ryan, Molly; Grenier, Ernesto; Castro, Anthony; Nemeroff, Charles B

    2012-01-01

    The relationship between psychotic disorders, in particular, schizophrenia, and neurodevelopmental abnormalities has been conceptualized in the latest literature. Dandy-Walker variant, defined by cystic dilatation of the fourth ventricle and hypoplasia of the inferior portion of the vermis without enlargement of the posterior fossa, is a distinctive entity believed to represent a mild subtype of Dandy-Walker complex. The authors hypothesize a correlation between new onset of psychosis and cerebellar abnormalities in an adolescent patient.

  9. Anesthesia management in a pediatric patient with Dandy-Walker syndrome

    Directory of Open Access Journals (Sweden)

    Zeynep Baysal Yıldırım

    2011-09-01

    Full Text Available General anesthesia management of patients with Dandy-Walker syndrome is important since intubation may be difficult due to concomitant anomalies such as hydrocephalus, micrognathia and cleft palate. It should be considered that these patients may require postoperative intensive care support. In this article, anesthesia management of a patient with Dandy-Walker syndrome underwent persistent ventriculo-peritoneal shunt was presented. J Clin Exp Invest 2011; 2 (3: 327-329.

  10. Bipolar Disorder in a Young Girl with Dandy-Walker Syndrome

    Directory of Open Access Journals (Sweden)

    Mahin Eslami Shahre Babaki

    2015-11-01

    Full Text Available  Dandy-Walker syndrome is a congenital brain malformation involving the cerebellum and the fourth ventricle. The key features of this syndrome are mental retardation, cerebellar ataxia, and symptoms related to hydrocephaly. The psychiatric aspects of this syndrome have been insufficiently appreciated. Described here is a 17- year- old girl with an acute manic episode emerged in the course of Dandy-Walker syndrome. Presentation and treatment are then addressed.

  11. Adaptation of Escherichia coli to glucose promotes evolvability in lactose.

    Science.gov (United States)

    Phillips, Kelly N; Castillo, Gerardo; Wünsche, Andrea; Cooper, Tim F

    2016-02-01

    The selective history of a population can influence its subsequent evolution, an effect known as historical contingency. We previously observed that five of six replicate populations that were evolved in a glucose-limited environment for 2000 generations, then switched to lactose for 1000 generations, had higher fitness increases in lactose than populations started directly from the ancestor. To test if selection in glucose systematically increased lactose evolvability, we started 12 replay populations--six from a population subsample and six from a single randomly selected clone--from each of the six glucose-evolved founder populations. These replay populations and 18 ancestral populations were evolved for 1000 generations in a lactose-limited environment. We found that replay populations were initially slightly less fit in lactose than the ancestor, but were more evolvable, in that they increased in fitness at a faster rate and to higher levels. This result indicates that evolution in the glucose environment resulted in genetic changes that increased the potential of genotypes to adapt to lactose. Genome sequencing identified four genes--iclR, nadR, spoT, and rbs--that were mutated in most glucose-evolved clones and are candidates for mediating increased evolvability. Our results demonstrate that short-term selective costs during selection in one environment can lead to changes in evolvability that confer longer term benefits. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  12. A new walker with upper trunk suspension system for severely disabled patients.

    Science.gov (United States)

    Scoppetta, C; Scoppetta, M

    2013-10-01

    We have recently designed a new type of walker for those severely disabled patients who cannot walk with commonly used medical walkers. A drawing and the description of this new walker is reported in order to permit the worldwide companies as well as artisans to develop and produce it for the people affected from severe motor problems. This walker supposes the patient wearing either a modified climbing harness or equipped clothes and being suspended to the walking frame. It consists in two series of bands suspending the patient from the frame; the upper one suspends him for the upper part of his trunk, the lower one by his pelvis. This walker is suggested for patients belonging to three principal groups: (1) Persons who have no trunk control (e.g.: patients affected by severe stroke or ataxias). (2) Persons whose walk is allowed only if they achieve a significant reduction (up to 30-40%) of the their body weight charging on trunk, spine, and lower limbs. (3) Persons who need a differentiated reduction of the body weight either among anterior and posterior side or among their right and left part of the body (hemiparesis, Parkinson disease, scoliosis, kyphosis). Creating this walker is easy; producing costs are low; there are no maintenance costs.

  13. Aesthetic Image of the Animal Epithet in Alice Walker's Short Story "Everyday Use"

    Directory of Open Access Journals (Sweden)

    Shaimaa Hadi Radhi

    2017-11-01

    Full Text Available In her short story Everyday Use, the African American writer Alice Walker labels her female characters Mrs. Johnson, and her two daughters: Maggie, and Dee by associating them with an animal quality. In my present paper I attempt to show the central and pivotal role played by the mechanism of 'Animal Epithet' in order to investigate to what extent does the writer apply the theory of 'Womanism' to her short fiction's protagonist and the other characters. Walker wants the reader to share her investigation journey in order to find a logical answer for the crucial questions raised in the research-paper: Why does Walker portray female characters by comparing them to animals? How does Walker manage to treat this topic aesthetically? What portrait of black woman does she prove? To answer these central questions, Walker is committed to construct her short narrative work on the base of the key elements of inversion, signifying, and quilting-like. Walker, as a womanist and animal activist is defiant and ridiculous of the mainstream agent of humanism represented by white males. She aesthetically inverts the meaning of the negative, dehumanizing image devised and everyday used by the men of ruling class into aesthetic and positive one to represent the identity of black women.

  14. Design Principles of DNA Enzyme-Based Walkers: Translocation Kinetics and Photoregulation.

    Science.gov (United States)

    Cha, Tae-Gon; Pan, Jing; Chen, Haorong; Robinson, Heather N; Li, Xiang; Mao, Chengde; Choi, Jong Hyun

    2015-07-29

    Dynamic DNA enzyme-based walkers complete their stepwise movements along the prescribed track through a series of reactions, including hybridization, enzymatic cleavage, and strand displacement; however, their overall translocation kinetics is not well understood. Here, we perform mechanistic studies to elucidate several key parameters that govern the kinetics and processivity of DNA enzyme-based walkers. These parameters include DNA enzyme core type and structure, upper and lower recognition arm lengths, and divalent metal cation species and concentration. A theoretical model is developed within the framework of single-molecule kinetics to describe overall translocation kinetics as well as each reaction step. A better understanding of kinetics and design parameters enables us to demonstrate a walker movement near 5 μm at an average speed of ∼1 nm s(-1). We also show that the translocation kinetics of DNA walkers can be effectively controlled by external light stimuli using photoisomerizable azobenzene moieties. A 2-fold increase in the cleavage reaction is observed when the hairpin stems of enzyme catalytic cores are open under UV irradiation. This study provides general design guidelines to construct highly processive, autonomous DNA walker systems and to regulate their translocation kinetics, which would facilitate the development of functional DNA walkers.

  15. Dandy-Walker Malformation: is the 'tail sign' the key sign?

    Science.gov (United States)

    Bernardo, Silvia; Vinci, Valeria; Saldari, Matteo; Servadei, Francesca; Silvestri, Evelina; Giancotti, Antonella; Aliberti, Camilla; Porpora, Maria Grazia; Triulzi, Fabio; Rizzo, Giuseppe; Catalano, Carlo; Manganaro, Lucia

    2015-12-01

    The study aims to demonstrate the value of the 'tail sign' in the assessment of Dandy-Walker malformation. A total of 31 fetal magnetic resonance imaging (MRI), performed before 24 weeks of gestation after second-line ultrasound examination between May 2013 and September 2014, were examined retrospectively. All MRI examinations were performed using a 1.5 Tesla magnet without maternal sedation. Magnetic resonance imaging diagnosed 15/31 cases of Dandy-Walker malformation, 6/31 of vermian partial caudal agenesis, 2/31 of vermian hypoplasia, 4/31 of vermian malrotation, 2/31 of Walker-Warburg syndrome, 1/31 of Blake pouch cyst and 1/31 of rhombencephalosynapsis. All data were compared with fetopsy results, fetal MRI after the 30th week or postnatal MRI; the follow-up depended on the maternal decision to terminate or continue pregnancy. In our review study, we found the presence of the 'tail sign'; this sign was visible only in Dandy-Walker malformation and Walker-Warburg syndrome. The 'tail sign' could be helpful in the difficult differential diagnosis between Dandy-Walker, vermian malrotation, vermian hypoplasia and vermian partial agenesis. © 2015 John Wiley & Sons, Ltd.

  16. An Architect Cicada in Brazilian Rainforest: Guyalna chlorogena (Walker).

    Science.gov (United States)

    Béguin, C F

    2017-04-01

    To study the noteworthy nest building behavior of the nymph of the Brazilian Rainforest cicada Guyalna chlorogena (Walker) during the last year of its underground life, we monitored a large number of edifices, consisting of a vertical well (up to 1 m deep) with a turret (20 to 40 cm tall) on top, and we also performed experiments. We have shown that the buildings are occupied by a single nymph, male or female, which increases the height of its turret each night by about 3 cm, during a short active growing phase. The nymph softens and reshapes the apex by pushing upwards a lump of freshly mixed soaked clay, without any opening present, i. e., without ever exposing itself to the outside. We also established that the nymph is very active once its building is achieved. For example, it restores the height of the turret to its original value when shortening and opens the top of its building in case of variation of environmental parameters. Finally, we have shown how the nymph opens its edifice to reach the outside for molting into an adult stage (imago). With this work, we contributed to a better understanding of the nesting behavior of Amazon cicadas.

  17. Third annual Walker Branch Watershed research symposium. Program and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    The methods and concepts of watershed research, originally applied in an experimental or monitoring mode to relatively small catchments, are increasingly being used at larger scales and for specific applied problems. Research at Oak Ridge National Laboratory, the Tennessee Valley Authority, the US Forest Service, and other agencies and institutions participating in this symposium reflects research over a broad range of spatial scales that is being integrated through large-scale experiments along with computer modeling and graphical interfaces. These research projects address the basic atmospheric, geophysical, biogeochemical, and biological processes that regulate the responses of forested ecosystems to natural environmental variation and anthropogenic stresses. Regional and global issues addressed by presentations include emissions of carbon dioxide, methane, and other hydrocarbons; deposition of sulfate, nitrate, and mercury; land-use changes; biological diversity; droughts; and water quality. The reports presented in this symposium illustrate a wide range of methods and approaches and focus more on concepts and techniques than on a specific physical site. Sites and projects that have contributed research results to this symposium include Walker Branch Watershed (DOE), the Coweeta Hydrologic Laboratory and LTER site (USFS and NSF), Great Smoky Mountains National Park (research funded by NPS, TVA, and EPRI), Imnavait Creek, Alaska (DOE), the TVA-Norris Whole-tree Facility (TVA and EPRI), and DOE`s Biomass Program.

  18. Central brain herniation in shunted Dandy Walker cyst.

    Science.gov (United States)

    Mandiwanza, Tafadzwa; Kaliaperumal, Chandrasekaran; Caird, John

    2013-06-01

    Dandy-Walker Syndrome (DWS) is a constellation of congenital anomalies of the central nervous system consisting of cerebellar vermis hypoplasia or agenesis, cystic dilatation of the fourth ventricle, enlarged posterior fossa, and a high tentorium. Hydrocephalus is a common occurrence in DWS and its treatment varies between shunting-ventriculoperitoneal or cystoperitoneal or both, endoscopic cyst fenestration, and third ventriculostomy. Chronic cerebral herniation is a known complication of treatment in DWS; however, we present an unusual case of central brain herniation. A 2 year old boy with shunted DWS presented with status epilepticus. Initial CT brain scan showed no increase in ventricle or cyst size; however, tapping the shunt reservoir did not yield any CSF prompting a shunt revision. Postoperatively, he was very slow to wake and subsequently experienced an episode of fixed pupils and extensor posturing. MRI brain demonstrated severe herniation of both thalami through the tentorium. This child had chronic central brain herniation (CCBH) secondary to the shunting of his cyst. To our knowledge, this is the first case of CCBH following treatment of DW cyst.

  19. Dandy-Walker Malformation: A Clinical and Surgical Outcome Analysis.

    Science.gov (United States)

    Bokhari, Iram; Rehman, Lal; Hassan, Sher; Hashim, M Sattar

    2015-06-01

    To determine the clinical presentations, complications and mortality in patients with Dandy-Walker Malformation (DWM) after surgery i.e., shunt with y-connector. Case series. Neurosurgery Ward, JPMC, Karachi, from January 2009 to December 2013. Cases of DWM, with associated hydrocephalus, further confirmed on CT scan of brain, were admitted through OPD. Those who were previously operated, those with other associated co-morbid or anomalies were excluded from this study. Combined drainage of the ventricular system and posterior fossa cyst, via dual shunt i.e. cystoperitoneal and ventriculoperitoneal shunt with y-connector was performed in all patients. Complications and mortality after surgical intervention in these patients were noted upto one month after surgery. The data analysis for descriptive statistics was done on SPSS version 20. In this study of 70 patients, majority of the patients were female aged between 1 - 2 years. Hydrocephalus was the predominant symptom as being present in all patients, followed by cerebellar signs in 60 (86%), and other in 5 (7.14%) patients. Complications of surgery were infection and shunt fracture dislocation in 7 (10%) each, malpositioning and shunt blockage in 6 (8.5%) each within one month of surgery, intracranial haemorrhage in 5 (7.14%) patients. Only one patient (1.42%) expired after surgical intervention. In DWM, the commonest presentation is that of hydrocephalus. Shunt malfunction and infection are the commonest complication after shunting. Dual shunt with y-connector has the lowest mortality when compared with other methods for treatment of shunt with y-connector.

  20. A retrospective benefit-cost analysis of the 1997 stair-fall requirements for baby walkers.

    Science.gov (United States)

    Rodgers, Gregory B; Leland, Elizabeth W

    2008-01-01

    Based on estimates from the U.S. Consumer Product Safety Commission (CPSC), there were about 25,000 baby walker-related injuries treated annually in U.S. hospital emergency departments during the early 1990s. This amounted to about 8 injuries for every 1000 baby walkers in use. Most injuries resulted from falls down stairs. After CPSC initiated a regulatory proceeding in 1994, the CPSC staff worked with industry to address the stair-fall hazard. This cooperative effort resulted in requirements designed to prevent stair-fall injuries that became effective in 1997 as part of a revised voluntary safety standard. This study presents a retrospective benefit-cost analysis of the 1997 stair-fall requirements. The benefits were defined as the reduction in the costs of injuries resulting from the use of the safer walkers. The costs were defined as the additional resource costs associated with making baby walkers safer. The study found that the stair-fall requirements were highly effective in reducing the risk of stair-fall injury, and that the benefits of the requirements substantially exceeded the costs. The expected net benefits (i.e., benefits minus costs) amounted to an average of about $169 per walker, over the walker's expected product life. Given current U.S. sales of about 600,000 baby walkers annually, the present value of the expected net benefits associated with 1 year's production amounts to over $100 million annually. A sensitivity analysis showed that the major findings were robust with respect to variations in underlying assumptions.

  1. Obituary: Richard L. (Dick) Walker, Jr., 1938-2005

    Science.gov (United States)

    Pier, Jeffrey R.; Mason, Brian

    2005-12-01

    Dick Walker, 67, died 30 March 2005 in Flagstaff, AZ, following a long illness. He was born on 9 March 1938 in Hampton, Iowa and grew up in Waterloo, Iowa. As a child, Dick was fascinated with astronomy and built his own telescope. He saved his pennies and bought and read every book on the subject he could find. He also raised pigeons, naming four of them Hertzsprung, Hoyle, Gamow, and Kron. In 1957, the year Sputnik was launched, Dick began his college studies at the University of Northern Iowa in Cedar Falls. In 1959, he transferred to the State University of Iowa (subsequently renamed the University of Iowa) in Iowa City, where he earned a BA degree in astronomy and physics in 1963. He joined the staff of the U.S. Naval Observatory in Washington, DC, where he worked in the Time Service Division for a year before his assignment to the Astrometry and Astrophysics Division. Dick relocated to Flagstaff, AZ, in 1966 to continue his Naval Observatory service at the Flagstaff Station. His retirement in May 1999, ended a thirty-six-year career with USNO. Dick was first and foremost an observational astronomer. From the mid 1960s through the late 1970s, much of Dick's time was devoted to the measurement of binary stars, observing with the 12-inch and 26-inch refractors in Washington and later the 40-inch and 61-inch reflectors in Flagstaff. He also made many trips to Lick Observatory to work with the 36-inch Clark Refractor there. During this time he consulted with Charles Worley, who was observing on the 26-inch, to make sure time was well-spent examining doubles that could not be observed in Washington. This period of observing overlapped with the early years of speckle interferometry, and Dick's observations, made with the largest telescope used for micrometry at the time, were very important for ascertaining the veracity of this new technique. He was a studious and very careful observer of doubles and made over 8,000 measures, resulting in almost 3,000 mean positions

  2. Comparison of metabolic cost and cardiovascular response to stair ascending and descending with walkers and canes in older adults.

    Science.gov (United States)

    Foley, Michael; Bowen, Brett

    2014-09-01

    To compare oxygen cost (mL·kg(-1)·m(-1)) and cardiovascular response (beats/m) and oxygen consumption (mL·kg(-1)·min(-1)) and heart rate (beats/min) to stair ascending and descending with walkers, with canes, and without assistive devices (ADs) in older adults. Descriptive, repeated measures. Indoor stairway. Convenience sample of able-bodied volunteers, non-AD users (N=14; mean age, 63.71 ± 11.7 y; mean body mass, 72.7 ± 14.1 kg; mean height, 165.7 ± 9.2 cm). Participants performed 4 randomized trials of stair ascending and descending at their own self-selected speed with 3 ADs: single-point cane, standard walker (SW), and wheeled walker (WW). They also performed unassisted stair ascending and descending. Each trial consisted of a 5-minute steady-state session followed by a 2-minute data collection period. Steady-state expired ventilations were collected in Douglas bags for metabolic analysis. Oxygen cost (mL·kg(-1)·m(-1)), heart rate (HR) response (beats/m), oxygen consumption (mL·kg(-1)·min(-1)), and HR (beats/min) were compared for each trial of stair ascending and descending using analysis of variance repeated measures (Pstair ascending and descending using the single-point cane (121%), SW (217%), and WW (232%) compared with unassisted stair ascending and descending (Pstair ascending and descending using the single-point cane (116%), SW (126%), and WW (147%) compared with unassisted stair ascending and descending (Pstair ascending and descending with the ADs compared with unassisted stair ascending and descending. Participants stair ascended and descended at significantly (Pspeeds during trials with the ADs. This research should aid clinicians by providing evidence to base recommendations on regarding AD usage when encountering stairs during home and community ambulation. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  3. The Dynamical Classification of Centaurs which Evolve into Comets

    Science.gov (United States)

    Wood, Jeremy R.; Horner, Jonathan; Hinse, Tobias; Marsden, Stephen; Swinburne University of Technology

    2016-10-01

    Centaurs are small Solar system bodies with semi-major axes between Jupiter and Neptune and perihelia beyond Jupiter. Centaurs can be further subclassified into two dynamical categories - random walk and resonance hopping. Random walk Centaurs have mean square semi-major axes () which vary in time according to a generalized diffusion equation where ~t2H. H is the Hurst exponent with 0 for resonance hopping Centaurs is not well described by generalized diffusion.The aim of this study is to determine which dynamical type of Centaur is most likely to evolve into each class of comet. 31,722 fictional massless test particles were integrated for 3 Myr in the 6-body problem (Sun, Jovian planets, test particle). Initially each test particle was a member of one of four groups. The semi-major axes of all test particles in a group were clustered within 0.27 au from a first order, interior Mean Motion resonance of Neptune. The resonances were centered at 18.94 au, 22.95 au, 24.82 au and 28.37 au.If the perihelion of a test particle reached particle was considered to be a comet and classified as either a random walk or resonance hopping Centaur. The results showed that over 4,000 test particles evolved into comets within 3 Myr. 59% of these test particles were random walk and 41% were resonance hopping. The behavior of the semi-major axis in time was usually well described by generalized diffusion for random walk Centaurs (ravg = 0.98) and poorly described for resonance hopping Centaurs (ravg = 0.52). The average Hurst exponent was 0.48 for random walk Centaurs and 0.20 for resonance hopping Centaurs. Random walk Centaurs were more likely to evolve into short period comets while resonance hopping Centaurs were more likely to evolve into long period comets. For each initial cluster, resonance hopping Centaurs took longer to evolve into comets than random walk Centaurs. Overall the population of random walk Centaurs averaged 143 kyr to evolve into comets, and the population of

  4. How Do Ants Make Sense of Gravity? A Boltzmann Walker Analysis of Lasius niger Trajectories on Various Inclines

    Science.gov (United States)

    Khuong, Anaïs; Lecheval, Valentin; Fournier, Richard; Blanco, Stéphane; Weitz, Sébastian; Bezian, Jean-Jacques; Gautrais, Jacques

    2013-01-01

    The goal of this study is to describe accurately how the directional information given by support inclinations affects the ant Lasius niger motion in terms of a behavioral decision. To this end, we have tracked the spontaneous motion of 345 ants walking on a 0.5×0.5 m plane canvas, which was tilted with 5 various inclinations by rad ( data points). At the population scale, support inclination favors dispersal along uphill and downhill directions. An ant's decision making process is modeled using a version of the Boltzmann Walker model, which describes an ant's random walk as a series of straight segments separated by reorientation events, and was extended to take directional influence into account. From the data segmented accordingly ( segments), this extension allows us to test separately how average speed, segments lengths and reorientation decisions are affected by support inclination and current walking direction of the ant. We found that support inclination had a major effect on average speed, which appeared approximately three times slower on the incline. However, we found no effect of the walking direction on speed. Contrastingly, we found that ants tend to walk longer in the same direction when they move uphill or downhill, and also that they preferentially adopt new uphill or downhill headings at turning points. We conclude that ants continuously adapt their decision making about where to go, and how long to persist in the same direction, depending on how they are aligned with the line of maximum declivity gradient. Hence, their behavioral decision process appears to combine klinokinesis with geomenotaxis. The extended Boltzmann Walker model parameterized by these effects gives a fair account of the directional dispersal of ants on inclines. PMID:24204636

  5. The fire-walker's high: affect and physiological responses in an extreme collective ritual.

    Directory of Open Access Journals (Sweden)

    Ronald Fischer

    Full Text Available How do people feel during extreme collective rituals? Despite longstanding speculation, few studies have attempted to quantify ritual experiences. Using a novel pre/post design, we quantified physiological fluctuations (heart rates and self-reported affective states from a collective fire-walking ritual in a Mauritian Hindu community. Specifically, we compared changes in levels of happiness, fatigue, and heart rate reactivity among high-ordeal participants (fire-walkers, low-ordeal participants (non-fire-walking participants with familial bonds to fire-walkers and spectators (unrelated/unknown to the fire-walkers. We observed that fire-walkers experienced the highest increase in heart rate and reported greater happiness post-ritual compared to low-ordeal participants and spectators. Low-ordeal participants reported increased fatigue after the ritual compared to both fire-walkers and spectators, suggesting empathetic identification effects. Thus, witnessing the ritualistic suffering of loved ones may be more exhausting than experiencing suffering oneself. The findings demonstrate that the level of ritual involvement is important for shaping affective responses to collective rituals. Enduring a ritual ordeal is associated with greater happiness, whereas observing a loved-one endure a ritual ordeal is associated with greater fatigue post-ritual.

  6. A local-world evolving hypernetwork model

    Science.gov (United States)

    Yang, Guang-Yong; Liu, Jian-Guo

    2014-01-01

    Complex hypernetworks are ubiquitous in the real system. It is very important to investigate the evolution mechanisms. In this paper, we present a local-world evolving hypernetwork model by taking into account the hyperedge growth and local-world hyperedge preferential attachment mechanisms. At each time step, a newly added hyperedge encircles a new coming node and a number of nodes from a randomly selected local world. The number of the selected nodes from the local world obeys the uniform distribution and its mean value is m. The analytical and simulation results show that the hyperdegree approximately obeys the power-law form and the exponent of hyperdegree distribution is γ = 2 + 1/m. Furthermore, we numerically investigate the node degree, hyperedge degree, clustering coefficient, as well as the average distance, and find that the hypernetwork model shares the scale-free and small-world properties, which shed some light for deeply understanding the evolution mechanism of the real systems.

  7. The Evolving Resource Metadata Infrastructure

    Science.gov (United States)

    Biemesderfer, Chris

    The search and discovery mechanisms that will facilitate and simplify systematic research on the Internet depend on systematic classifications of resources, as well as on standardized access to such metadata. The principles and technologies that will make this possible are evolving in the work of the Internet Engineering Task Force and the digital library initiatives, among others. The desired outcome is a set of standards, tools, and practices that permits both cataloging and retrieval to be comprehensive and efficient.

  8. Ranking in evolving complex networks

    Science.gov (United States)

    Liao, Hao; Mariani, Manuel Sebastian; Medo, Matúš; Zhang, Yi-Cheng; Zhou, Ming-Yang

    2017-05-01

    Complex networks have emerged as a simple yet powerful framework to represent and analyze a wide range of complex systems. The problem of ranking the nodes and the edges in complex networks is critical for a broad range of real-world problems because it affects how we access online information and products, how success and talent are evaluated in human activities, and how scarce resources are allocated by companies and policymakers, among others. This calls for a deep understanding of how existing ranking algorithms perform, and which are their possible biases that may impair their effectiveness. Many popular ranking algorithms (such as Google's PageRank) are static in nature and, as a consequence, they exhibit important shortcomings when applied to real networks that rapidly evolve in time. At the same time, recent advances in the understanding and modeling of evolving networks have enabled the development of a wide and diverse range of ranking algorithms that take the temporal dimension into account. The aim of this review is to survey the existing ranking algorithms, both static and time-aware, and their applications to evolving networks. We emphasize both the impact of network evolution on well-established static algorithms and the benefits from including the temporal dimension for tasks such as prediction of network traffic, prediction of future links, and identification of significant nodes.

  9. A random walk model to evaluate autism

    Science.gov (United States)

    Moura, T. R. S.; Fulco, U. L.; Albuquerque, E. L.

    2018-02-01

    A common test administered during neurological examination in children is the analysis of their social communication and interaction across multiple contexts, including repetitive patterns of behavior. Poor performance may be associated with neurological conditions characterized by impairments in executive function, such as the so-called pervasive developmental disorders (PDDs), a particular condition of the autism spectrum disorders (ASDs). Inspired in these diagnosis tools, mainly those related to repetitive movements and behaviors, we studied here how the diffusion regimes of two discrete-time random walkers, mimicking the lack of social interaction and restricted interests developed for children with PDDs, are affected. Our model, which is based on the so-called elephant random walk (ERW) approach, consider that one of the random walker can learn and imitate the microscopic behavior of the other with probability f (1 - f otherwise). The diffusion regimes, measured by the Hurst exponent (H), is then obtained, whose changes may indicate a different degree of autism.

  10. Robust Redundant Input Reliable Tracking Control for Omnidirectional Rehabilitative Training Walker

    Directory of Open Access Journals (Sweden)

    Ping Sun

    2014-01-01

    Full Text Available The problem of robust reliable tracking control on the omnidirectional rehabilitative training walker is examined. The new nonlinear redundant input method is proposed when one wheel actuator fault occurs. The aim of the study is to design an asymptotically stable controller that can guarantee the safety of the user and ensure tracking on a training path planned by a physical therapist. The redundant degrees of freedom safety control and the asymptotically zero state detectable concept of the walker are presented, the model of redundant degree is constructed, and the property of center of gravity constant shift is obtained. A controller that can satisfy asymptotic stability is obtained using a common Lyapunov function for admissible uncertainties resulting from an actuator fault. Simulation results confirm the effectiveness of the proposed method and verify that the walker can provide safe sequential motion when one wheel actuator is at fault.

  11. Bilateral Macular Edema: A New Ocular Feature of Dandy-Walker Syndrome.

    Science.gov (United States)

    Tranos, P; Dervenis, N; Kiouras, S

    2017-01-01

    To describe a case of bilateral cystoid macular edema in a patient with Dandy-Walker syndrome. An 18-year-old male was referred to our tertiary referral center for evaluation of his decreased visual acuity. Detailed ophthalmic examination and imaging revealed the presence of bilateral cystoid macular edema, which was successfully treated with intravitreal triamcinolone injections (2 mg in 0.05 ml). Recurrence of macular edema developed after a period of approximately four months. This is an unusual ophthalmic manifestation of Dandy-Walker syndrome. Cystoid macular edema should be included in the differential diagnosis of subjects with Dandy-Walker syndrome presenting with decreased vision. The pathogenetic mechanism for the development macular edema in this case is not clear. Intravitreal triamcinolone is an effective treatment, but edema was recurrent in our case. Other approaches (such as oral Acetazolamide or intravitreal Anti-VEGF) have to be considered as well.

  12. Empowering and Assisting Natural Empowering and Assisting Natural Human Mobility: The Simbiosis Walker

    Directory of Open Access Journals (Sweden)

    Anselmo Frizera-Neto

    2011-08-01

    Full Text Available This paper presents the complete development of the Simbiosis Smart Walker. The device is equipped with a set of sensor subsystems to acquire user-machine interaction forces and the temporal evolution of user's feet during gait. The authors present an adaptive filtering technique used for the identification and separation of different components found on the human-machine interaction forces. This technique allowed isolating the components related with the navigational commands and developing a Fuzzy logic controller to guide the device. The Smart Walker was clinically validated at the Spinal Cord Injury Hospital of Toledo - Spain, presenting great acceptability by spinal chord injury patients and clinical staff.

  13. Test pilots 1962 - Armstrong, Walker, Dana, Peterson, McKay, Thompson, Butchart

    Science.gov (United States)

    1962-01-01

    The research pilots at what in 1962 was called the Flight Research Center standing in front of the X-1E. They are (left to right) Neil Armstrong, Joe Walker, Bill Dana, Bruce Peterson, Jack McKay, Milt Thompson, and Stan Butchart. of the group, Armstrong, Walker, Dana, McKay and Thompson all flew the X-15. Bruce Peterson flew the M2-F2 and HL-10 lifting bodies, while Stan Butchart was the B-29 drop plane pilot for many of the D-558-II and X-1 series research aircraft.

  14. A late presentation of Dandy-Walker malformation and aortic coarctation.

    Science.gov (United States)

    Venturini, Elio; Magni, Lucia; Pucci, Giovanna; Mazzinghi, Fabio

    2017-05-01

    The Dandy-Walker malformation is a rare anomaly of the posterior cranial fossa. Concomitant brain or systemic malformations are frequent and can influence the outcome. Associated cardiac congenital defects usually induce a poor prognosis. We report a case of a 58-yearold man with hydrocephalus, in whom Dandy-Walker malformation was diagnosed, for the first time, after the demonstration of aortic coarctation. This association is very rare and only a few cases have been described; moreover, to our knowledge, this is the first description of this incidence in a middle-aged patient. The characteristic of diseases and physiopathologic features are discussed, focusing attention on the rare and late clinical manifestations.

  15. Ocular Findings in a Case of Trisomy 18 With Variant of Dandy-Walker Syndrome

    Directory of Open Access Journals (Sweden)

    Fong-Fong Lim

    2010-10-01

    Full Text Available Trisomy 18 is the second most common chromosomal syndrome and has multiple dysmorphic features. However, ocular findings in trisomy 18 are rarely reported. Retinal folds are the most common ocular finding described to date, although retinal hypopigmentation, dysplasia, and areas of hemorrhage and gliosis are also found in trisomy 18. Dandy-Walker syndrome is a brain malformation that has been reported in association with numerous chromosomal abnormalities, although it has rarely been reported in association with trisomy 18. Here, we present a case of trisomy 18 with ocular pathology and variant of Dandy-Walker syndrome, a combination that has not previously been reported.

  16. Simulation of the Lower Walker River Basin hydrologic system, west-central Nevada, using PRMS and MODFLOW models

    Science.gov (United States)

    Allander, Kip K.; Niswonger, Richard G.; Jeton, Anne E.

    2014-01-01

    Walker Lake is a terminal lake in west-central Nevada with almost all outflow occurring through evaporation. Diversions from Walker River since the early 1900s have contributed to a substantial reduction in flow entering Walker Lake. As a result, the lake is receding, and salt concentrations have increased to a level in which Oncorhynchus clarkii henshawi (Lahontan Cutthroat trout) are no longer present, and the lake ecosystem is threatened. Consequently, there is a concerted effort to restore the Walker Lake ecosystem and fishery to a level that is more sustainable. However, Walker Lake is interlinked with the lower Walker River and adjacent groundwater system which makes it difficult to understand the full effect of upstream water-management actions on the overall hydrologic system including the lake level, volume, and dissolved-solids concentrations of Walker Lake. To understand the effects of water-management actions on the lower Walker River Basin hydrologic system, a watershed model and groundwater flow model have been developed by the U.S. Geological Survey in cooperation with the Bureau of Reclamation and the National Fish and Wildlife Foundation.

  17. 77 FR 67811 - Porter-Walker LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for...

    Science.gov (United States)

    2012-11-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Porter-Walker LLC; Supplemental Notice That Initial Market-Based Rate Filing...-referenced proceeding of Porter-Walker LLC's application for market-based rate authority, with an...

  18. The evolvability of programmable hardware

    Science.gov (United States)

    Raman, Karthik; Wagner, Andreas

    2011-01-01

    In biological systems, individual phenotypes are typically adopted by multiple genotypes. Examples include protein structure phenotypes, where each structure can be adopted by a myriad individual amino acid sequence genotypes. These genotypes form vast connected ‘neutral networks’ in genotype space. The size of such neutral networks endows biological systems not only with robustness to genetic change, but also with the ability to evolve a vast number of novel phenotypes that occur near any one neutral network. Whether technological systems can be designed to have similar properties is poorly understood. Here we ask this question for a class of programmable electronic circuits that compute digital logic functions. The functional flexibility of such circuits is important in many applications, including applications of evolutionary principles to circuit design. The functions they compute are at the heart of all digital computation. We explore a vast space of 1045 logic circuits (‘genotypes’) and 1019 logic functions (‘phenotypes’). We demonstrate that circuits that compute the same logic function are connected in large neutral networks that span circuit space. Their robustness or fault-tolerance varies very widely. The vicinity of each neutral network contains circuits with a broad range of novel functions. Two circuits computing different functions can usually be converted into one another via few changes in their architecture. These observations show that properties important for the evolvability of biological systems exist in a commercially important class of electronic circuitry. They also point to generic ways to generate fault-tolerant, adaptable and evolvable electronic circuitry. PMID:20534598

  19. The 'E' factor -- evolving endodontics.

    Science.gov (United States)

    Hunter, M J

    2013-03-01

    Endodontics is a constantly developing field, with new instruments, preparation techniques and sealants competing with trusted and traditional approaches to tooth restoration. Thus general dental practitioners must question and understand the significance of these developments before adopting new practices. In view of this, the aim of this article, and the associated presentation at the 2013 British Dental Conference & Exhibition, is to provide an overview of endodontic methods and constantly evolving best practice. The presentation will review current preparation techniques, comparing rotary versus reciprocation, and question current trends in restoration of the endodontically treated tooth.

  20. Alzheimer random walk

    Science.gov (United States)

    Odagaki, Takashi; Kasuya, Keisuke

    2017-09-01

    Using the Monte Carlo simulation, we investigate a memory-impaired self-avoiding walk on a square lattice in which a random walker marks each of sites visited with a given probability p and makes a random walk avoiding the marked sites. Namely, p = 0 and p = 1 correspond to the simple random walk and the self-avoiding walk, respectively. When p> 0, there is a finite probability that the walker is trapped. We show that the trap time distribution can well be fitted by Stacy's Weibull distribution b(a/b){a+1}/{b}[Γ({a+1}/{b})]-1x^a\\exp(-a/bx^b)} where a and b are fitting parameters depending on p. We also find that the mean trap time diverges at p = 0 as p- α with α = 1.89. In order to produce sufficient number of long walks, we exploit the pivot algorithm and obtain the mean square displacement and its Flory exponent ν(p) as functions of p. We find that the exponent determined for 1000 step walks interpolates both limits ν(0) for the simple random walk and ν(1) for the self-avoiding walk as [ ν(p) - ν(0) ] / [ ν(1) - ν(0) ] = pβ with β = 0.388 when p ≪ 0.1 and β = 0.0822 when p ≫ 0.1. Contribution to the Topical Issue "Continuous Time Random Walk Still Trendy: Fifty-year History, Current State and Outlook", edited by Ryszard Kutner and Jaume Masoliver.

  1. Penentuan Distribusi Suhu pada Permukaan Geometri Tak Tentu Menggunakan Metode Random Walk

    Directory of Open Access Journals (Sweden)

    Balduyanus Yosep Godja

    2016-05-01

    Full Text Available Telah dilakukan penentuan distribusi suhu dalam keadaan tunak pada sebuah plat bergeometri tak tentu menggunakan metode Random Walk yang dilengkapi fungsi green. Setiap sisi plat dikondisikan bervariasi terhadap suhu dalam rentang 10°C sampai 100°C dengan 4 (empat konfigurasi berkeadaan steady. Persamaan Laplace yang mendeskripsikan permasalahan ini dihampiri dengan mensimulasikan sejumlah walker pada setiap titik domain permasalahan untuk kemudian secara acak disebar menuju ke setiap sisi plat. Hasil yang diperoleh untuk setiap kondisi plat menunjukkan kesalahan relatif terhadap solusi numerik metode iterasi jacobi yang telah menghampiri solusi analitik, secara rata-rata adalah 0,85%. Nilai kesalahan tersebut diperoleh dengan menggunakan 5000 walker. Penelitian ini juga mendapatkan bahwa akurasi hampiran ditentukan oleh banyaknya walker yang digunakan. Secara umum, semakin banyak jumlah walker yang digunakan maka akurasi hampiran akan semakin baik.

  2. Moebius syndrome with Dandy-Walker variant and agenesis of corpus callosum.

    Science.gov (United States)

    John, Jomol Sara; Vanitha, R

    2013-09-01

    Moebius syndrome is a rare congenital neurological disorder. The most frequent mode of presentation is facial diplegia with bilateral lateral rectus palsy, but there are variations. Here, we report a rare case of Moebius syndrome in a 15-month-old child with unilateral facial palsy, bilateral abducens nerve palsy with Dandy Walker variant, and complete agenesis of corpus callosum.

  3. Moebius syndrome with Dandy-Walker variant and agenesis of corpus callosum

    OpenAIRE

    Jomol Sara John; R Vanitha

    2013-01-01

    Moebius syndrome is a rare congenital neurological disorder. The most frequent mode of presentation is facial diplegia with bilateral lateral rectus palsy, but there are variations. Here, we report a rare case of Moebius syndrome in a 15-month-old child with unilateral facial palsy, bilateral abducens nerve palsy with Dandy Walker variant, and complete agenesis of corpus callosum.

  4. Fundamental solutions of the wave equation in Robertson-Walker spaces

    Science.gov (United States)

    Yagdjian, Karen; Galstian, Anahit

    2008-10-01

    In this article we construct the fundamental solutions for the wave equation in the Robertson-Walker spaces arising in the de Sitter model of the universe. We then use these fundamental solutions to represent solutions of the Cauchy problem for the equation with and without a source term.

  5. High Performance Sustainable School Design: Roy Lee Walker Elementary, McKinney, Texas.

    Science.gov (United States)

    SHW Group, Inc., Dallas, TX.

    This document describes the sustainable features of the Roy Lee Walker Elementary School (Texas), a prototype "Eco Education" school that blends the physical environment with the student learning process while protecting the site. The document also presents the process of integrating sustainability criteria in all phases of the school's…

  6. Influence of infant-walkers on motor development: mimicking spastic diplegia?

    NARCIS (Netherlands)

    Engelbert, R. H.; van Empelen, R.; Scheurer, N. D.; Helders, P. J.; van Nieuwenhuizen, O.

    1999-01-01

    We discuss two patients, who used an infant walker during the period in which they learned to walk. The influence on qualitative and quantitative motor development is illustrated in this report. A disharmonic and delayed motor development, contractures of the calf-muscles and motor development

  7. [Stress parameters and behaviour of horses in walkers with and without the use of electricity].

    Science.gov (United States)

    Giese, C; Gerber, V; Howald, M; Bachmann, I; Burger, D

    2014-04-01

    In order to investigate stress responses of horses in walkers with and without electricity, 12 horses were trained during 3 weeks in a horse walker with and without the use of electricity (3.7 kV). To evaluate the stress response, cortisol levels in the blood were measured, the heart rate was monitored using the Polar® system and the behaviour was evaluated. Neither the cortisol levels nor the heart rates showed any relevant statistically significant difference between horses moved in the horse walker with or without the use of electricity. The highest cortisol levels and heart rates were recorded during the first week (habituation period). A significant difference could be observed regarding spontaneous compartment changes: while this happened mainly during the first week and before the first use of electricity, no horses changed compartments in the periods when electricity was used and thereafter. The results of this study indicate that the use of electricity in the horse walker does not seem to cause significant detectable stress in the horses.

  8. Sound production in an Australian cockroach, Megazosteria patula (Walker) (Blattodea: Blattidae: Polyzosteriinae).

    Science.gov (United States)

    Rentz, David

    2017-02-13

    The large, diurnal Australian cockroach, Megazosteria patula (Walker), produces a sound when disturbed. The sound was found to be a form of stridulation caused by the rubbing of pegs on the underside of the thoracic segments against a ridge on the following segment.

  9. Stick-slip actuation of electrostatic stepper micropositioners for data storage-the µWalker

    NARCIS (Netherlands)

    Patrascu, M.; Stramigioli, Stefano

    2005-01-01

    This paper is about the /spl mu/Walker, an electrostatic stepper motor mainly intended for positioning the data probes with respect to the storage medium in a data storage device. It can deliver forces up to 1.7 mN for ranges as large as 140 /spl mu/m. Controlling the stick-slip effects at the

  10. Swing-Leg Retraction for Limit Cycle Walkers Improves Disturbance Rejection

    NARCIS (Netherlands)

    Hobbelen, D.G.E.; Wisse, M.

    2008-01-01

    Limit cycle walkers are bipeds that exhibit a stable cyclic gaitwithout requiring local controllability at all times during gait. A well-known example of limit cycle walking is McGeer’s “passive dynamic walking,” but the concept expands to actuated bipeds as involved in this study. One of the

  11. On Maximal Surfaces in Certain Non-Flat 3-Dimensional Robertson-Walker Spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Alfonso, E-mail: aromero@ugr.es [Universidad de Granada, Departamento de Geometria y Topologia (Spain); Rubio, Rafael M., E-mail: rmrubio@uco.es [Universidad de Cordoba, Departamento de Matematicas, Campus de Rabanales (Spain)

    2012-09-15

    An upper bound for the integral, on a geodesic disc, of the squared length of the gradient of a distinguished function on any maximal surface in certain non-flat 3-dimensional Robertson-Walker spacetimes is obtained. As an application, a new proof of a known Calabi-Bernstein's theorem is given.

  12. The Deep Semantics of Imagery in Alice Walker's The Color Purple ...

    African Journals Online (AJOL)

    Hinged on this theoretical framework, the paper assesses the deep semantics of imagery in Walker's The Color Purple and highlights the salient non-ostensive references of the text and the new world it proposes. The analysis reveals the key to a deeper and broader perception of God, the imperativeness of equality of ...

  13. Collateral Damage: Veterans and Domestic Violence in Mari Sandoz's "The Tom-Walker"

    Science.gov (United States)

    Bahr, Kathy

    2010-01-01

    "The Tom-Walker" combines the best of Sandoz's realism with her worst attempts at moralizing. Unable to divine exactly what political configuration right-wing post-World War II sentiments might take, Sandoz nevertheless feared a fascist uprising in this country. Perhaps because these concerns dominated her thoughts at the time, she allowed her…

  14. Panel Discussion: Cover Crops Used at Georgia Forestry Commission Flint River and Walker Nurseries

    Science.gov (United States)

    Jeff Fields

    2005-01-01

    Flint River Nursery, located near Montezuma, Georgia, has used rye, wheat, brown top millet, and sorghum sudan grass for cover crops. Flint River has just begun to return to a summer cover crop situation. At Walker Nursery, located near Reidsville, Georgia, certified rye has been sown by the State Department of Corrections (DOC) for their harvesting, with a benefit to...

  15. Experience in the management of Dandy-Walker syndrome in an ...

    African Journals Online (AJOL)

    Dandy-Walker Syndrome (DWS) is a congenital brain malformation involving the cerebellum and the fluid spaces around it. There is atresia of foramenofMagendie and Lushka resulting in a complete absence of the part of the brain located between the two cerebellar hemispheres (cerebellarvermis) and cystic dilatation of ...

  16. Giant occipital meningocele in an 8-year-old child with Dandy-Walker malformation.

    Science.gov (United States)

    Talamonti, Giuseppe; Picano, Marco; Debernardi, Alberto; Bolzon, Moreno; Teruzzi, Mario; D'Aliberti, Giuseppe

    2011-01-01

    The possibility of an association between Dandy-Walker malformation and occipital meningocele is well-known. However, just an overall number of about 40 cases have been previously reported. Giant occipital meningocele has been described only in three newborns. Incidence, pathology, clinical presentation, and proper management of this association are still poorly defined. An 8-year-old boy with Dandy-Walker malformation and giant (25 cm in diameter) occipital meningocele is presented. This boy was born without any apparent occipital mass and harbored no other significant malformations including hydrocephalus. On admission, he was neurologically intact and the giant occipital mass presented partially calcified cyst walls. Treatment consisted of the excision of the occipital malformation, cranioplasty, and cysto-peritoneal shunt. Outcome was excellent. To the best of our knowledge, among the few reported patients with Dandy-Walker malformation associated to occipital meningocele, this is the oldest one and the one with the largest occipital meningocele; he is unique with calcified walls of the occipital meningocele and the only one who survived the repair of the giant malformation. In Dandy-Walker malformation, occipital meningocele may develop and grow regardless of hydrocephalus. Giant size may be reached and the cyst may become calcified. Surgical repair may warrant favorable outcome.

  17. Menkes' disease with a Dandy-Walker variant: case report

    Energy Technology Data Exchange (ETDEWEB)

    Bekiesinska-Figatowska, M. [Dept. of Diagnostic Imaging, Central Railway Hospital, Warsaw (Poland); Rokicki, D.; Gremida, M. [Dept. of Metabolic Diseases, Children' s Memorial Health Institute, Warsaw (Poland); Walecki, J. [Dept. of Radiology and Diagnostic Imaging, Medical Centre for Postgraduate Education, Warsaw (Poland)

    2001-11-01

    We report a boy with Menkes' disease in whom MRI revealed delayed myelination of the white matter, brain atrophy and tortuosity of the intracranial vessels. The characteristic MRI features of Menkes' disease were accompanied by a Dandy-Walker variant. (orig.)

  18. Parenchymal Neurocutaneous Melanosis in Association with Intraventricular Dermoid and Dandy-Walker Variant: A Case Report

    Science.gov (United States)

    Won, Yoo Dong; Kim, Ki Tae; Chang, Eun Deok; Huh, Pil Woo

    2006-01-01

    Neurocutaneous melanosis (NCM) is a rare congenital disease that is characterized by the presence of large or multiple congenital melanocytic nevi and melanotic lesions of the central nervous system. We report here on the CT and MR imaging findings of an unusual case of NCM that was associated with intraventricular dermoid and Dandy-Walker malformation. PMID:16799276

  19. Moebius syndrome with Dandy-Walker variant and agenesis of corpus callosum

    Science.gov (United States)

    John, Jomol Sara; Vanitha, R.

    2013-01-01

    Moebius syndrome is a rare congenital neurological disorder. The most frequent mode of presentation is facial diplegia with bilateral lateral rectus palsy, but there are variations. Here, we report a rare case of Moebius syndrome in a 15-month-old child with unilateral facial palsy, bilateral abducens nerve palsy with Dandy Walker variant, and complete agenesis of corpus callosum. PMID:24470815

  20. Prenatal diagnosis of the Dandy-Walker syndrome by sonography and computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Toelly, E.; Ebner, F.; Oberbauer, R.W.

    1984-07-01

    A case of Dandy-Walker-syndrome is presented, comparing the value of sonography and CT in intrauterine diagnosis. Together with a review of the literature of the subject, pathogenesis, morphology and prognosis in regard to the psychomotoric development are discussed. 3 figs.

  1. Dandy-Walker malformation with postaxial polydactly: a new case of Pierquin syndrome.

    Science.gov (United States)

    Passalacqua, Cristóbal A; Villegas, Victor P; Aracena, Mariana I; Mellado, Cecilia X

    2013-04-01

    The combination of Dandy-Walker malformation, other central nervous system anomalies, and postaxial polydactyly has been reported previously in two pairs of siblings. We propose the name 'Pierquin syndrome' for this combination and we report a new patient with this disorder.

  2. Psychosis in a Case of Dandy-Walker Syndrome: A Case Report.

    Science.gov (United States)

    Dawra, Ripu Daman; Karia, Sagar; Shah, Nilesh; Desousa, Avinash

    2017-05-01

    Dandy Walker Syndrome (DWS) is a congenital malformation with brain abnormalities, intellectual disabilities, epilepsy and visible structural changes in particular brain structures. We present here a case of psychosis in an 18-year-old male with DWS, epilepsy and intellectual disability. The purpose of this paper is to discuss the clinically relevant issues, psychopharmacological issues, neuropsychiatric manifestations and consultation liaison issues involved.

  3. Trans-sphenoidal encephalocele in association with Dandy-Walker complex and cardiovascular anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Joy, H.M.; Barker, C.S. [Wessex Neurological Centre, Southampton (United Kingdom); Small, J.H. [Dept. of Radiology, Royal Bournemouth Hospital (United Kingdom); Armitage, M. [Bournemouth Diabetes and Endocrine Centre, Royal Bournemouth Hospital (United Kingdom)

    2001-01-01

    We present a case of trans-sphenoidal encephalomeningocele in association with a posterior cranial fossa malformation which fulfils the criteria for the Dandy-Walker complex. Congenital cardiovascular defects were also present. An abnormality of neural crest development may be responsible for the combined occurrence of these anomalies. (orig.)

  4. Parenchymal neurocutaneous melanosis in association with intraventricular dermoid and Dandy-walker variant: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Joo; Won, Yoo Dong; Kim, Ki Tae; Chang, Eun Deok; Huh, Pil Woo [The Catholic University of Korea, College of Medicine, Uijongbu (Korea, Republic of)

    2006-06-15

    Neurocutaneous melanosis (NCM) is a rare congenital disease that is characterized by the presence of large or multiple congenital melanocytic nevi and melanotic lesions of the central nervous system. We report here on the CT and MR imaging findings of an unusual case of NCM that was associated with intraventricular dermoid and Dandy-Walker malformation.

  5. Active transtensional intracontinental basins: Walker Lane in the western Great Basin

    Science.gov (United States)

    Jayko, Angela S.; Bursik, Marcus

    2012-01-01

    The geometry and dimensions of sedimentary basins within the Walker Lane are a result of Plio-Pleistocene transtensive deformation and partial detachment of the Sierra Nevada crustal block from the North American plate. Distinct morpho-tectonic domains lie within this active transtensive zone. The northeast end of the Walker Lane is partly buried by active volcanism of the southern Cascades, and adjacent basins are filled or poorly developed. To the south, the basin sizes are moderate, 25–45km × 15–10 km, with narrow 8-12km wide mountain ranges mainly oriented N-S to NNE. These basins form subparallel arrays in discrete zones trending about 300° and have documented clockwise rotation. This is succeeded to the south by a releasing stepover domain ∼85-100km wide, where the basins are elongated E-W to ENE, small (∼15-30km long, 5-15km wide), and locally occupied by active volcanic centers. The southernmost part of the Walker Lane is structurally integrated, with high to extreme relief. Adjacent basins are elongate, 50-200km long and ∼5 -20km wide. Variations in transtensive basin orientations in the Walker Lane are largely attributable to variations in strain partitioning. Large basins in the Walker Lane have 2-6km displacement across basin bounding faults with up to 3 km of clastic accumulation based on gravity and drill hole data. The sedimentary deposits of the basins may include interbedded volcanic deposits with bimodal basaltic and rhyolitic associations. The basins may include lacustrine deposits that record a wide range of water chemistry from cold fresh water conditions to saline-evaporative

  6. Extraction of user's navigation commands from upper body force interaction in walker assisted gait

    Directory of Open Access Journals (Sweden)

    Pons José L

    2010-08-01

    Full Text Available Abstract Background The advances in technology make possible the incorporation of sensors and actuators in rollators, building safer robots and extending the use of walkers to a more diverse population. This paper presents a new method for the extraction of navigation related components from upper-body force interaction data in walker assisted gait. A filtering architecture is designed to cancel: (i the high-frequency noise caused by vibrations on the walker's structure due to irregularities on the terrain or walker's wheels and (ii the cadence related force components caused by user's trunk oscillations during gait. As a result, a third component related to user's navigation commands is distinguished. Results For the cancelation of high-frequency noise, a Benedict-Bordner g-h filter was designed presenting very low values for Kinematic Tracking Error ((2.035 ± 0.358·10-2 kgf and delay ((1.897 ± 0.3697·101ms. A Fourier Linear Combiner filtering architecture was implemented for the adaptive attenuation of about 80% of the cadence related components' energy from force data. This was done without compromising the information contained in the frequencies close to such notch filters. Conclusions The presented methodology offers an effective cancelation of the undesired components from force data, allowing the system to extract in real-time voluntary user's navigation commands. Based on this real-time identification of voluntary user's commands, a classical approach to the control architecture of the robotic walker is being developed, in order to obtain stable and safe user assisted locomotion.

  7. Subtalar joint kinematic correlations with footprint arch index in race walkers.

    Science.gov (United States)

    Elvira, J L L; Vera-García, F J; Meana, M

    2008-06-01

    The aim of the paper was to analyze the relationship between footprint arch index and subtalar joint movement in race walkers. Thirteen young, highly skilled race walkers volunteered to participate. We obtained dominant-foot footprints in a bipedal stance. The arch index was measured to classify arch height. We also conducted a photogrammetric video-3D study on a running track. The support phase was recorded while subjects race walked at their individual competition speed. We calculated 4 angle time series describing the ankle joint kinematics during the support phase. Five specific step instants were calculated for each angle and correlated with the arch index. Race walkers were grouped according to arch height to compare. We also correlated the arch index with the time in medial support, and time to change from lateral to medial support during the stance phase. In the calcaneal angle we found correlations with the footprint (r=0.81; Prace walkers adopt a characteristic propulsion technique in the end of the support. No statistical differences were found in the rearfoot angle, which has been previously associated to specific injuries in running. In conclusion, race walkers with higher arches exhibit a more pronounced support with the lateral side of the foot and they do so for a longer time. Conversely, subjects with flatter feet support with the medial side of the foot. The footprint has been found to be a good predictor for the technique employed with respect to the medial and lateral strike of the foot reflected by the calcaneal angle. Coaches should keep this in mind from both performance and injury prevention viewpoints.

  8. Ground reaction force and 3D biomechanical characteristics of walking in short-leg walkers.

    Science.gov (United States)

    Zhang, Songning; Clowers, Kurt G; Powell, Douglas

    2006-12-01

    Short-leg walking boots offer several advantages over traditional casts. However, their effects on ground reaction forces (GRF) and three-dimensional (3D) biomechanics are not fully understood. The purpose of the study was to examine 3D lower extremity kinematics and joint dynamics during walking in two different short-leg walking boots. Eleven (five females and six males) healthy subjects performed five level walking trials in each of three conditions: two testing boot conditions, Gait Walker (DeRoyal Industries, Inc.) and Equalizer (Royce Medical Co.), and one pair of laboratory shoes (Noveto, Adidas). A force platform and a 6-camera Vicon motion analysis system were used to collect GRFs and 3D kinematic data during the testing session. A one-way repeated measures analysis of variance (ANOVA) was used to evaluate selected kinematic, GRF, and joint kinetic variables (p<0.05). The results revealed that both short-leg walking boots were effective in minimizing ankle eversion and hip adduction. Neither walker increased the bimodal vertical GRF peaks typically observed in normal walking. However, they did impose a small initial peak (<1BW) earlier in the stance phase. The Gait Walker also exhibited a slightly increased vertical GRF during midstance. These characteristics may be related to the sole materials/design, the restriction of ankle movements, and/or the elevated heel heights of the tested walkers. Both walkers appeared to increase the demand on the knee extensors while they decreased the demand of the knee and hip abductors based on the joint kinetic results.

  9. Peripartum hysterectomy: an evolving picture.

    LENUS (Irish Health Repository)

    Turner, Michael J

    2012-02-01

    Peripartum hysterectomy (PH) is one of the obstetric catastrophes. Evidence is emerging that the role of PH in modern obstetrics is evolving. Improving management of postpartum hemorrhage and newer surgical techniques should decrease PH for uterine atony. Rising levels of repeat elective cesarean deliveries should decrease PH following uterine scar rupture in labor. Increasing cesarean rates, however, have led to an increase in the number of PHs for morbidly adherent placenta. In the case of uterine atony or rupture where PH is required, a subtotal PH is often sufficient. In the case of pathological placental localization involving the cervix, however, a total hysterectomy is required. Furthermore, the involvement of other pelvic structures may prospectively make the diagnosis difficult and the surgery challenging. If resources permit, PH for pathological placental localization merits a multidisciplinary approach. Despite advances in clinical practice, it is likely that peripartum hysterectomy will be more challenging for obstetricians in the future.

  10. Extreme evolved solar systems (EESS)

    Science.gov (United States)

    Gaensicke, Boris

    2017-08-01

    In just 20 years, we went from not knowing if the solar system is a fluke of Nature to realising that it is totally normal for stars to have planets. More remarkably, it is now clear that planet formation is a robust process, as rich multi-planet systems are found around stars more massive and less massive than the Sun. More recently, planetary systems have been identified in increasingly complex architectures, including circumbinary planets, wide binaries with planets orbiting one or both stellar components, and planets in triple stellar systems.We have also learned that many planetary systems will survive the evolution of their host stars into the white dwarf phase. Small bodies are scattered by unseen planets into the gravitational field of the white dwarfs, tidally disrupt, form dust discs, and eventually accrete onto the white dwarf, where they can be spectroscopically detected. HST/COS has played a critical role in the study these evolved planetary systems, demonstrating that overall the bulk composition of the debris is rocky and resembles in composition the inner the solar system, including evidence for water-rich planetesimals. Past observations of planetary systems at white dwarfs have focused on single stars with main-sequence progenitors of 1.5 to 2.5Msun. Here we propose to take the study of evolved planetary systems into the extremes of parameter ranges to answer questions such as: * How efficient is planet formation around 4-10Msun stars? * What are the metallicities of the progenitors of debris-accreting white dwarfs?* What is the fate of circumbinary planets?* Can star-planet interactions generate magnetic fields in the white dwarf host?

  11. CERN internal communication is evolving

    CERN Multimedia

    2016-01-01

    CERN news will now be regularly updated on the CERN People page (see here).      Dear readers, All over the world, communication is becoming increasingly instantaneous, with news published in real time on websites and social networks. In order to keep pace with these changes, CERN's internal communication is evolving too. From now on, you will be informed of what’s happening at CERN more often via the “CERN people” page, which will frequently be updated with news. The Bulletin is following this trend too: twice a month, we will compile the most important articles published on the CERN site, with a brand-new layout. You will receive an e-mail every two weeks as soon as this new form of the Bulletin is available. If you have interesting news or stories to share, tell us about them through the form at: https://communications.web.cern.ch/got-story-cern-website​. You can also find out about news from CERN in real time...

  12. Coexistance of cerebral sinovenous thrombosis and Dandy Walker malformation in newborn.

    Science.gov (United States)

    Gverić-Ahmetasević, Snjezana; Colić, Ana; Gverić, Tugomir; Gasparović, Vesna Elvedi; Pavlisa, Goran; Ozretić, David

    2011-01-01

    Cerebral sinovenous thrombosis in neonatal period may cause neurological impairment, epilepsy, and lead to stroke. It is caused primarily by coagulopathy of numerous reasons, occasionally perinatal asphyxia, traumatic delivery and hyperhomocysteinemia. Dandy-Walker malformation is characterized by agenesis or hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa. Dandy-Walker malformation, variant, and mega cisterna magna represent a spectrum of developmental anomalies. Insults to developing cerebellar hemispheres and the fourth ventricle are believed to be the cause of malformation. Our patient was born from noncomplicated pregnancy, noncomplicated nontraumatic vaginal delivery at term, excellent Apgar scores, without peculiarities in clinical status. She was brest-fed by the 42nd hour of life when she had rightsided seizures during sleep that repeated for five times in next 24 hours. Brain Ultrasound (US) revealed clot in left lateral ventricle, slight dilatation of left ventricle, both sided periventricular echodensity, ischemia, slight enlargement of forth ventricle and a bit smaller cerebellum. There was no visible flow through left transverse, superior sagittal and straight sinus. Magnetic Resonance (MRI) confirmed the finding and showed thrombosis of left and right transverse venous sinuses and confluence of sinuses. Electroencephalogram (EEG) showed leftsided focal changes. The newborn was treated with phenobarbiton for 8 days and had no convulsions during that period. All coagulation parameters, homocistein, lipoproteins (a) and D-dimers were normal. There were no mutations on FV R506Q, PT 20210A, MTHFR 677C/T. No antiphospholipides were found. Heart US showed no structural anomalies. No other patology or risk factors were present at the time. Before discharge, US showed hydrocephalus. Flow in affected sinuses was visible with color Doppler. MRI showed recanalization of affected sinuses, also

  13. Baby walker injury awareness among grade-12 girls in a high-prevalence Arab country in the Middle East.

    Science.gov (United States)

    Grivna, Michal; Barss, Peter; Al-Hanaee, Amna; Al-Dhahab, Ayesha; Al-Kaabi, Fatima; Al-Muhairi, Shamma

    2015-03-01

    Baby walkers (BWs) are a consumer product frequently associated with infant injuries. With little research in the Middle East and few population studies anywhere, female students in grade 12 in the United Arab Emirates were surveyed, assessing the prevalence of use, perceived safety, and interventions. The study population included grade-12 students in a large UAE city. Multistage random sampling selected 4/8 female Arab government schools and 3 classes each from science and arts tracks for interview by self-administered questionnaire. Response was 100%, with a total of 696 students, 55% (n = 385) of whom were Emirati citizens; 90% (n = 619) of the families used/had used BWs. Among the reasons for use, 92% reported "keeping baby safe," with 11% perceiving BWs as very safe and 74% as moderately safe. Only 16% perceived that BWs could cause injuries. Despite causing many injuries, including fatalities, BWs were perceived to be safe and used by nearly all families. Effective education of professionals, patients, the public, and decision makers is needed. Governments should consider countermeasures such as prohibiting importation, sales, and advertising, together with public education and provision of stationary activity centers. © 2013 APJPH.

  14. Spatial Distribution and Minimum Sample Size for Overwintering Larvae of the Rice Stem Borer Chilo suppressalis (Walker) in Paddy Fields.

    Science.gov (United States)

    Arbab, A

    2014-10-01

    The rice stem borer, Chilo suppressalis (Walker), feeds almost exclusively in paddy fields in most regions of the world. The study of its spatial distribution is fundamental for designing correct control strategies, improving sampling procedures, and adopting precise agricultural techniques. Field experiments were conducted during 2011 and 2012 to estimate the spatial distribution pattern of the overwintering larvae. Data were analyzed using five distribution indices and two regression models (Taylor and Iwao). All of the indices and Taylor's model indicated random spatial distribution pattern of the rice stem borer overwintering larvae. Iwao's patchiness regression was inappropriate for our data as shown by the non-homogeneity of variance, whereas Taylor's power law fitted the data well. The coefficients of Taylor's power law for a combined 2 years of data were a = -0.1118, b = 0.9202 ± 0.02, and r (2) = 96.81. Taylor's power law parameters were used to compute minimum sample size needed to estimate populations at three fixed precision levels, 5, 10, and 25% at 0.05 probabilities. Results based on this equation parameters suggesting that minimum sample sizes needed for a precision level of 0.25 were 74 and 20 rice stubble for rice stem borer larvae when the average larvae is near 0.10 and 0.20 larvae per rice stubble, respectively.

  15. An evolving model of online bipartite networks

    Science.gov (United States)

    Zhang, Chu-Xu; Zhang, Zi-Ke; Liu, Chuang

    2013-12-01

    Understanding the structure and evolution of online bipartite networks is a significant task since they play a crucial role in various e-commerce services nowadays. Recently, various attempts have been tried to propose different models, resulting in either power-law or exponential degree distributions. However, many empirical results show that the user degree distribution actually follows a shifted power-law distribution, the so-called Mandelbrot’s law, which cannot be fully described by previous models. In this paper, we propose an evolving model, considering two different user behaviors: random and preferential attachment. Extensive empirical results on two real bipartite networks, Delicious and CiteULike, show that the theoretical model can well characterize the structure of real networks for both user and object degree distributions. In addition, we introduce a structural parameter p, to demonstrate that the hybrid user behavior leads to the shifted power-law degree distribution, and the region of power-law tail will increase with the increment of p. The proposed model might shed some lights in understanding the underlying laws governing the structure of real online bipartite networks.

  16. Finite difference method to find period-one gait cycles of simple passive walkers

    Science.gov (United States)

    Dardel, Morteza; Safartoobi, Masoumeh; Pashaei, Mohammad Hadi; Ghasemi, Mohammad Hassan; Navaei, Mostafa Kazemi

    2015-01-01

    Passive dynamic walking refers to a class of bipedal robots that can walk down an incline with no actuation or control input. These bipeds are sensitive to initial conditions due to their style of walking. According to small basin of attraction of passive limit cycles, it is important to start with an initial condition in the basin of attraction of stable walking (limit cycle). This paper presents a study of the simplest passive walker with point and curved feet. A new approach is proposed to find proper initial conditions for a pair of stable and unstable period-one gait limit cycles. This methodology is based on finite difference method which can solve the nonlinear differential equations of motion on a discrete time. Also, to investigate the physical configurations of the walkers and the environmental influence such as the slope angle, the parameter analysis is applied. Numerical simulations reveal the performance of the presented method in finding two stable and unstable gait patterns.

  17. Evaluation of Bone Cancer Pain Induced by Different Doses of Walker 256 Mammary Gland Carcinoma Cells.

    Science.gov (United States)

    Dong, Changsheng; Wu, RuiXin; Wu, Jing; Guo, Jing; Wang, Fangyuan; Fu, Yanli; Wang, Qing; Xu, Ling; Wang, Juyong

    2016-01-01

    Cancer pain is a complex medical syndrome. Understanding its underlying mechanisms relies on the use of animal models which can mimic the human condition. A crucial component of this model is the quantity of tumor cells; however, the exact relationship between the doses of tumor cells on bone cancer pain is yet unknown. We explored the relationship of different doses of Walker 256 carcinoma cells using a bone cancer pain model in rats, and evaluated its success and stability. Experimental animal study using a comparative design. Experimental Animal Center and Tumor Institute of Traditional Chinese Medicine. We constructed the bone cancer pain model by implanting Walker 256 carcinoma cells into the right tibia of Sprague-Dawley (SD) rats (150 - 170 g). Spontaneous pain, mechanical threshold, and paw withdrawal latency (PWL) were measured and x-ray, bone mineral density (BMD), histological, interleukin-1 beta (IL-1beta) mRNA, carboxyterminal telopeptide of type I collagen (ICTP), and bone alkaline phosphatase (BAP) were analyzed for bone pain model evaluation. The results showed that: (1) the 3 doses (3×105, 3.5×105, 4×105) of Walker 256 carcinoma cells can induce bone cancer pain from day 7 to day 21 after implantation into the right tibia of SD rats; (2) compared to the control group, 3×105, 3.5×105, and 4×105 Walker 256 carcinoma cells produced different pain manifestations, where the 3.5×105 dose of Walker 256 carcinoma cells resulted in the greatest bone cancer pain response; (3) the 3.5×105 dose induced the lowest mortality rate in rats; (4) Walker 256 carcinoma cells (3×105, 3.5×105, and 4×105) resulted in a significant decrease in the general condition and body weight of rats, where the 3.5×105 and 4×105 doses of carcinoma cells produced a greater effect than 3×105 dose of carcinoma cells; (5) progressive spontaneous pain, PWL, and mechanical threshold were exacerbated by 3.5×105 and 4×105 doses of carcinoma cells; (6) implantation of 3.5×105

  18. Impulsive behavior and recurrent major depression associated with dandy-walker variant.

    Science.gov (United States)

    Kim, Ji Hyun; Kim, Tae Ho; Choi, Young Chil; Chung, Soon-Cheol; Moon, Seok Woo

    2013-09-01

    Reported herein is a case of recurrent major depression with impulse control difficulty in a 33-year-old man with Dandy-Walker variant. He was diagnosed as having major depressive disorder a year before he presented himself to the authors' hospital, and had a history of three-time admission to a psychiatric unit in the previous 12 months. He was readmitted and treated with sodium valporate 1,500 mg/day, mirtazapine 45 mg/day, and quetiapine 800 mg/day during the three months that he was confined in the authors' hospital, and the symptoms were reduced within three months but remained thereafter. This is the only case so far reporting recurrent depression with impulse control difficulty associated with Dandy-Walker variant. This case implies that any cerebellar lesion may cause the appearance of recurrent depression with impulse control difficulty in major depressive disorder.

  19. Nasopharyngeal teratoma, congenital diaphragmatic hernia and Dandy-Walker malformation - a yet uncharacterized syndrome.

    Science.gov (United States)

    Gupta, N; Shastri, S; Singh, P K; Jana, M; Mridha, A; Verma, G; Kabra, M

    2016-11-01

    An association of congenital diaphragmatic hernia, dandy walker malformation and nasopharyngeal teratoma is very rare. Here, we report a fourth case with this association where chromosomal microarray and whole exome sequencing (WES) was performed to understand the underlying genetic basis. Findings of few variants especially a novel variation in HIRA provided some insights. An association of congenital diaphragmatic hernia, dandy walker malformation and nasopharyngeal teratoma is very rare. Here, we report a fourth case with this association where chromosomal microarray and whole exome sequencing (WES) was performed to understand the underlying genetic basis. Findings of few variants especially a novel variation in HIRA provided some insights. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Dandy-Walker syndrome with severe velopharyngeal dysfunction: a contraindication for Le Fort I surgery?

    Science.gov (United States)

    Nelke, Kamil H; Pawlak, Wojciech; Gerber, Hanna

    2015-01-01

    Dandy-Walker syndrome is a rare congenital brain deformation. Most symptoms are related with fourth ventricle and skull base malformations. Quite often, symptoms develop from infancy or progress rapidly. Cerebellar dysfunction, lack of muscle coordination, and skull deformities involving eye movement might be present. There are several Dandy-Walker syndrome complex types. We present a 23-year-old patient who had a severe dentofacial deformity with mandibular prognathism and extremely undeveloped maxillary bone resulting in palatopharyngeal and velopharyngeal dysfunction with complete lack of soft palate function resulting in increased speech tone and volume. Performing Le Fort I osteotomy in this case is greatly controversial and might result in even greater loss of function or even its total lack. Velopharyngeal complex is very important, and every surgeon should consider its value while planning Le Fort I osteotomies.

  1. Dandy-Walker Variant with Schizophrenia: Comorbidity or Cerebellar Cognitive Affective Syndrome?

    Science.gov (United States)

    Sinha, Pallavi; Tarwani, Jatin; Kumar, Pankaj; Garg, Amit

    2017-01-01

    Dandy-Walker complex (DWC) is a series of neurodevelopmental anomalies involving the posterior cranial fossa. The cerebellum has long been considered to be involved in motor coordination and balance. However, it has now been noted to play an important role in higher order cognitive, emotional, and behavioral functions. The concept of cerebellar cognitive affective syndrome, describing a coherent spectrum of cognitive and behavioral disturbances in adults following cerebellar damage has long been proposed. There have been reported cases of co-occurring psychiatric symptoms and DWC in literature, but the conclusive evidence for an association between the same remains lacking. Herein, we report a case of schizophrenia presenting along with Dandy-Walker Variant.

  2. Schizophrenia-like psychosis and dandy-walker variant comorbidity: case report.

    Science.gov (United States)

    Bozkurt Zincir, Selma; Kıvılcım, Yiğit; Izci, Filiz; Semiz, Umit Basar

    2014-01-01

    Dandy-Walker variant is a developmental malformation consisting of cerebellar hypoplasia and cystic dilatation of the fourth ventricle. Previous research has proposed a possible role for the cerebellum in cognition and in schizophrenia. In this paper we report a schizophrenia-like psychotic disorder in a 30 year-old woman with Dandy-Walker variant. The patient was treated with risperidone 6 mg/day, biperiden 4 mg/day and risperidone depot 50 mg injections fortnightly, and most of the symptoms were ameliorated within 2 months. The similar cognitive profile to populations with cerebellar pathology and rarity of the condition strongly suggests that there may be direct relationship between cerebellar pathology and appearence of psychotic symptoms.

  3. Women in History--Madame C. J. Walker 1867-1919

    Science.gov (United States)

    Huber, Germaine W.

    2009-01-01

    This article profiles Madame C. J. Walker. Sarah Breedlove was born on December 23, 1867, the fifth of six children of Owen and Minerva Breedlove. Sarah was the first of the Breedlove children to be born after the end of slavery. Her parents died when she was six or seven years of age. At age fourteen she married Moses McWilliams, who also died in…

  4. Comparisons between swing phase characteristics of race walkers and distance runners

    OpenAIRE

    Smith, LC; Hanley, B

    2013-01-01

    The aim of this study was to analyze swing characteristics during race walking and to compare these with distance running. The rules of race walking demand that no visible flight time should occur and the stance leg must be straightened from initial contact to midstance. Previous research has not examined whether these rules also have an effect on swing and what consequences might arise. Ten male race walkers and ten male distance runners walked or ran respectively on an instrumented treadmil...

  5. Paciente com variante da síndrome de Dandy Walker

    Directory of Open Access Journals (Sweden)

    Robson Luis Ribeiro Andrade Filho

    2015-10-01

    Full Text Available O quadro que seria conhecido atualmente como Síndrome de Dandy Walker, foi caracterizada por um conjunto de sinais derivados de alterações na embriogênese, principalmente no que tange a gênese do sistema nervoso central. A patogenia é classificada majoritariamente em três formas, sendo a mais comum a variante de Dandy Walker. Tem-se por objetivo, o relato do caso de um paciente masculino, 3 meses de idade, portador da Variante da Síndrome de Dandy Walker. O paciente apresentava ao exame físico geral e específico dos sistemas: macrocefalia, hidrocele, apêndices em mãos e pés, microgenitália, hérnia inguinal. Em relação ao acometimento cardíaco, havia dilatação ventricular esquerda, bulhas hipofonéticas e sopros holossistólicos. Na ressonância magnética foi observada ausência de vermis cerebelar e aumento anormal do quarto ventrículo. Método: as informações foram obtidas mediante revisão de prontuário, exames de imagem e levantamento para estudo de literatura específica referente ao caso. Considerações finais e relevância: o caso relatado e o estudo das referências apontam a caracterização do paciente na variante de Dandy Walker, tendo em consideração seu fenótipo variável. Malformações devem ser pesquisadas intra e extracranianas através de pesquisa clínica e radiológica, de forma a minimizar as taxas de mortalidade em recém-nascidos portadores da síndrome.

  6. Performance of trichogrammatids as biocontrol agents of Pseudoplusia includens Walker (Lepidoptera: Noctuidae)

    OpenAIRE

    Regiane C. O. F. Bueno; Parra,José R.P.; Bueno, Adeney F.; HADDAD, Marinéia L

    2009-01-01

    Este estudo objetivou selecionar as linhagens de tricogramatídeos mais adequadas ao controle da lagarta falsa-medideira, Pseudoplusia includens Walker. Foram avaliados os parâmetros biológicos e a taxa de parasitismo de 11 linhagens de Trichogramma pretiosum Riley, uma linhagem de Trichogramma atopovirilia Oatman & Platner e uma linhagem de Trichogrammatoidea annulata De Santis, criadas em ovos de P. includens. Entre as espécies/linhagens avaliadas, a linhagem T. pretiosum RV, coletada em Rio...

  7. New Analytical Solution of the Equilibrium Ampere's Law Using the Walker's Method: a Didactic Example

    Science.gov (United States)

    Sousa, A. N. Laurindo; Ojeda-González, A.; Prestes, A.; Klausner, V.; Caritá, L. A.

    2017-12-01

    This work aims to demonstrate the analytical solution of the Grad-Shafranov (GS) equation or generalized Ampere's law, which is important in the studies of self-consistent 2.5-D solution for current sheet structures. A detailed mathematical development is presented to obtain the generating function as shown by Walker (RSPSA 91, 410, 1915). Therefore, we study the general solution of the GS equation in terms of the Walker's generating function in details without omitting any step. The Walker's generating function g(ζ) is written in a new way as the tangent of an unspecified function K(ζ). In this trend, the general solution of the GS equation is expressed as exp(- 2Ψ) = 4|K '(ζ)|2/cos2[K(ζ) - K(ζ ∗)]. In order to investigate whether our proposal would simplify the mathematical effort to find new generating functions, we use Harris's solution as a test, in this case K(ζ) = arctan(exp(i ζ)). In summary, one of the article purposes is to present a review of the Harris's solution. In an attempt to find a simplified solution, we propose a new way to write the GS solution using g(ζ) = tan(K(ζ)). We also present a new analytical solution to the equilibrium Ampere's law using g(ζ) = cosh(b ζ), which includes a generalization of the Harris model and presents isolated magnetic islands.

  8. Test pilots 1962 - Thompson, McKay, Dana, Armstrong, Peterson, Butchart, Walker

    Science.gov (United States)

    1962-01-01

    A group photo of NASA research pilots at the front door of the Flight Research Center headquarters building. In the front row are (left to right) Milt Thompson, Jack McKay, and Bill Dana. All three flew the X-15, and Thompson and Dana were also involved in the lifting body flights. McKay was injured in a crash landing in X-15 #2. Although he recovered, the injuries eventually forced him to retire from research flying. In the back row (left to right) are Neil Armstrong, Bruce Peterson, Stanley Butchart, and Joe Walker. Armstrong and Walker also both flew the X-15. Soon after this photo was taken, Armstrong was selected as an astronaut, and seven years later became the first man to walk on the Moon. Walker made the highest flight in the X-15, reaching 354,200 feet. He then went on to fly the Lunar Landing Research Vehicle, and was killed on June 8, 1966 when his F-104N collided with the XB-70. Peterson made the first flight in the HL-10 lifting body, and was later badly injured in the crash of the M2-F2 lifting body. Butchart flew a wide range of research missions in the 1950s, and was the B-29 drop plane pilot for a number of rocket flight.

  9. Detection of Gait Perturbations Based on Proprioceptive Information. Application to Limit Cycle Walkers

    Directory of Open Access Journals (Sweden)

    J. A. Gallego

    2012-01-01

    Full Text Available Walking on irregular surfaces and in the presence of unexpected events is a challenging problem for bipedal machines. Up to date, their ability to cope with gait disturbances is far less successful than humans’: Neither trajectory controlled robots, nor dynamic walking machines (Limit Cycle Walkers are able to handle them satisfactorily. On the contrary, humans reject gait perturbations naturally and efficiently relying on their sensory organs that, if needed, elicit a recovery action. A similar approach may be envisioned for bipedal robots and exoskeletons: An algorithm continuously observes the state of the walker and, if an unexpected event happens, triggers an adequate reaction. This paper presents a monitoring algorithm that provides immediate detection of any type of perturbation based solely on a phase representation of the normal walking of the robot. The proposed method was evaluated in a Limit Cycle Walker prototype that suffered push and trip perturbations at different moments of the gait cycle, providing 100% successful detections for the current experimental apparatus and adequately tuned parameters, with no false positives when the robot is walking unperturbed.

  10. HitWalker2: visual analytics for precision medicine and beyond.

    Science.gov (United States)

    Bottomly, Daniel; McWeeney, Shannon K; Wilmot, Beth

    2016-04-15

    The lack of visualization frameworks to guide interpretation and facilitate discovery is a potential bottleneck for precision medicine, systems genetics and other studies. To address this we have developed an interactive, reproducible, web-based prioritization approach that builds on our earlier work. HitWalker2 is highly flexible and can utilize many data types and prioritization methods based upon available data and desired questions, allowing it to be utilized in a diverse range of studies such as cancer, infectious disease and psychiatric disorders. Source code is freely available at https://github.com/biodev/HitWalker2 and implemented using Python/Django, Neo4j and Javascript (D3.js and jQuery). We support major open source browsers (e.g. Firefox and Chromium/Chrome). wilmotb@ohsu.edu Supplementary data are available at Bioinformatics online. Additional information/instructions are available at https://github.com/biodev/HitWalker2/wiki. © The Author 2015. Published by Oxford University Press.

  11. Do Canes or Walkers Make Any Difference? NonUse and Fall Injuries.

    Science.gov (United States)

    Luz, Clare; Bush, Tamara; Shen, Xiaoxi

    2017-04-01

    Examine patterns of cane and walker use as related to falls and fall injuries. Among people who fall at home, most do not have an assistive device with them when they fall. Nonusers who fall sustain more severe injuries. This was a cross-sectional study using a self-administered written survey completed by 262 people aged 60 and older who were community dwelling, cognitively intact, and current cane/walker users with a history of falls. They were recruited through clinical practice sites, churches, and senior housing in central Michigan. Outcomes of interest included patterns of device use, reasons for nonuse, device use at time of fall, and fall-related injuries. Seventy-five percent of respondents who fell were not using their device at the time of fall despite stating that canes help prevent falls. Reasons for nonuse included believing it was not needed, forgetfulness, the device made them feel old, and inaccessibility. Perceived risk was not high enough to engage in self-protective behavior. However, nonuse led to a significantly higher proportion of falls resulting in surgery than among device users. Among respondents requiring surgery, 100% were nonusers. Most respondents never received a home safety evaluation (68%) and only 50% received training on proper device use. Providers must place increased emphasis on the importance of cane/walker use for injury prevention through patient education to promote personal relevance, proper fitting, and training. New strategies are needed to improve device acceptability and accessibility.

  12. New Analytical Solution of the Equilibrium Ampere's Law Using the Walker's Method: a Didactic Example

    Science.gov (United States)

    Sousa, A. N. Laurindo; Ojeda-González, A.; Prestes, A.; Klausner, V.; Caritá, L. A.

    2018-02-01

    This work aims to demonstrate the analytical solution of the Grad-Shafranov (GS) equation or generalized Ampere's law, which is important in the studies of self-consistent 2.5-D solution for current sheet structures. A detailed mathematical development is presented to obtain the generating function as shown by Walker (RSPSA 91, 410, 1915). Therefore, we study the general solution of the GS equation in terms of the Walker's generating function in details without omitting any step. The Walker's generating function g( ζ) is written in a new way as the tangent of an unspecified function K( ζ). In this trend, the general solution of the GS equation is expressed as exp(- 2Ψ) = 4| K '( ζ)|2/cos2[ K( ζ) - K( ζ ∗)]. In order to investigate whether our proposal would simplify the mathematical effort to find new generating functions, we use Harris's solution as a test, in this case K( ζ) = arctan(exp( i ζ)). In summary, one of the article purposes is to present a review of the Harris's solution. In an attempt to find a simplified solution, we propose a new way to write the GS solution using g( ζ) = tan( K( ζ)). We also present a new analytical solution to the equilibrium Ampere's law using g( ζ) = cosh( b ζ), which includes a generalization of the Harris model and presents isolated magnetic islands.

  13. Protective Effect of Metformin Against Walker 256 Tumor Growth is Not Dependent on Metabolism Improvement

    Directory of Open Access Journals (Sweden)

    Claudinéia Conationi da Silva Franco

    2014-11-01

    Full Text Available Background/Aims: The objective of the current work was to test the effect of metformin on the tumor growth in rats with metabolic syndrome. Methods: We obtained pre-diabetic hyperinsulinemic rats by neonatal treatment with monosodium L-glutamate (MSG, which were chronically treated every day, from weaning to 100 day old, with dose of metformin (250 mg/kg body weight. After the end of metformin treatment, the control and MSG rats, treated or untreated with metformin, were grafted with Walker 256 carcinoma cells. Tumor weight was evaluated 14 days after cancer cell inoculation. The blood insulin, glucose levels and glucose-induced insulin secretion were evaluated. Results: Chronic metformin treatment improved the glycemic homeostasis in pre-diabetic MSG-rats, glucose intolerance, tissue insulin resistance, hyperinsulinemia and decreased the fat tissue accretion. Meanwhile, the metformin treatment did not interfere with the glucose insulinotropic effect on isolated pancreatic islets. Chronic treatment with metformin was able to decrease the Walker 256 tumor weight by 37% in control and MSG rats. The data demonstrated that the anticancer effect of metformin is not related to its role in correcting metabolism imbalances, such as hyperinsulinemia. However, in morphological assay to apoptosis, metformin treatment increased programmed cell death. Conclusion: Metformin may have a direct effect on cancer growth, and it may programs the rat organism to attenuate the growth of Walker 256 carcinoma.

  14. Effects of aquatic walking exercise using a walker in a chronic stroke patient.

    Science.gov (United States)

    Matsuda, Tadashi; Akezaki, Yoshiteru

    2017-07-01

    [Purpose] The aim of this study was to examine the usefulness of aquatic walking exercise using a walker for chronic stroke patients. We also examined the psychological effects on the study subject and the primary caregiver before and after aquatic walking exercise. [Subject and Methods] The subject was a 60-year-old male with bilateral paralysis after a cerebrovascular accident. The Fugl-Meyer Assessment (FMA) total score was 116 on the right and 115 on the left. The intervention combined aquatic and land walking exercise. A U-shaped walker was used for both water and land exercise. Continuous walking distance was the measure used to evaluate land walking ability. The psychological effects on the study subject and the primary caregiver were examined with the questionnaire. [Results] In aquatic walking, the mean time to walk 5 m showed an increase from the intervention after two months. After the aquatic walking and land walking combination, continuous walking distance also showed a prolonged trend. In the survey given to the main caregivers, improvements were observed. [Conclusion] Aquatic walking practice using a walker improved motivation in a chronic stroke patient, leading to improved walking ability, with a positive psychological influence on the participant and family caregiver.

  15. [Genetic analysis of two cases with Dandy-Walker deformed fetus].

    Science.gov (United States)

    Yao, Juan; Fang, Rong; Shen, Xueping; Shen, Guosong; Zhang, Su

    2017-10-10

    To explore the genetic etiology of two fetuses with Dandy-Walker malformation using single nucleotide polymorphism microarray (SNP-array). The fetuses and their parents were subjected to G banding karyotype analysis. The fetuses were also subjected to SNP-array analysis. The parents of both fetuses showed a normal karyotype. One fetus has a 46,X,?i(X)(q10), while for another conventional cell culture has failed. SNP-array showed that one fetus carried a 6p25.3p25.2 microdeletion, and another carried a Xp22.33p22.2 deletion and a Yq11.221q11 duplication. The abnormal fragments have involved FOXC1, SHOX and STS genes, which are associated with Dandy-Walker malformation. Alteration of 6p25.3p25.2, Xp22.33p22.2 copy numbers probably underlies the Dandy-Walker syndrome in the fetuses. The disorder may be attributed to abnormal expression of FOXC1, SHOX, and STS genes. SNP-array can provide an important supplement for prenatal diagnosis.

  16. A Novel Function for the Conserved Glutamate Residue in the Walker B Motif of Replication Factor C

    Directory of Open Access Journals (Sweden)

    Linda B. Bloom

    2013-03-01

    Full Text Available In all domains of life, sliding clamps tether DNA polymerases to DNA to increase the processivity of synthesis. Clamp loaders load clamps onto DNA in a multi-step process that requires ATP binding and hydrolysis. Like other AAA+ proteins, clamp loaders contain conserved Walker A and Walker B sequence motifs, which participate in ATP binding and hydrolysis, respectively. Mutation of the glutamate residue in Walker B motifs (or DExx-boxes in AAA+ proteins typically reduces ATP hydrolysis by as much as a couple orders of magnitude, but has no effect on ATP binding. Here, the Walker B Glu in each of the four active ATP sites of the eukaryotic clamp loader, RFC, was mutated to Gln and Ala separately, and ATP binding- and hydrolysis-dependent activities of the quadruple mutant clamp loaders were characterized. Fluorescence-based assays were used to measure individual reaction steps required for clamp loading including clamp binding, clamp opening, DNA binding and ATP hydrolysis. Our results show that the Walker B mutations affect ATP-binding-dependent interactions of RFC with the clamp and DNA in addition to reducing ligand-dependent ATP hydrolysis activity. Here, we show that the Walker B glutamate is required for ATP-dependent ligand binding activity, a previously unknown function for this conserved Glu residue in RFC.

  17. Land-sea thermal contrast determines the trend of Walker circulation simulated in atmospheric general circulation models

    Science.gov (United States)

    Yim, Bo Young; Yeh, Sang-Wook; Song, Hwan-Jin; Dommenget, Dietmar; Sohn, B. J.

    2017-06-01

    Strengthening or weakening of the Walker circulation can highly influence the global weather and climate variability by altering the location and strength of tropical heating. Therefore, there is considerable interest in understanding the mechanisms that lead to the trends in the Walker circulation intensity. Conventional wisdom indicates that a strengthening or weakening of the Walker circulation is primarily controlled by inhomogeneous sea surface temperature (SST) patterns across the tropical Pacific basin. However, we show that Atmospheric Model Intercomparison Project climate model simulations with identical SST forcing have different Walker circulation trends that can be linked to differences in land surface temperatures. More prominently, stronger land-sea thermal contrast leads to increases in the precipitation in South America as well as the sea level pressure in the eastern tropical Pacific through a local circulation, resulting in a strengthening of the Walker circulation trend. This implies that correctly simulating the land temperature in atmospheric models is crucial to simulating the intensity of the Walker circulation in the present climate as well as its future change.

  18. Upper-Ocean Heat Balance Processes and the Walker Circulation in CMIP5 Model Projections

    Science.gov (United States)

    Robertson, F. R.; Roberts, J. B.; Funk, C.; Lyon, B.; Ricciardulli, L.

    2012-01-01

    Considerable uncertainty remains as to the importance of mechanisms governing decadal and longer variability of the Walker Circulation, its connection to the tropical climate system, and prospects for tropical climate change in the face of anthropogenic forcing. Most contemporary climate models suggest that in response to elevated CO2 and a warmer but more stratified atmosphere, the required upward mass flux in tropical convection will diminish along with the Walker component of the tropical mean circulation as well. Alternatively, there is also evidence to suggest that the shoaling and increased vertical stratification of the thermocline in the eastern Pacific will enable a muted SST increase there-- preserving or even enhancing some of the dynamical forcing for the Walker cell flow. Over the past decade there have been observational indications of an acceleration in near-surface easterlies, a strengthened Pacific zonal SST gradient, and globally-teleconnected dislocations in precipitation. But is this evidence in support of an ocean dynamical thermostat process posited to accompany anthropogenic forcing, or just residual decadal fluctuations associated with variations in warm and cold ENSO events and other stochastic forcing? From a modeling perspective we try to make headway on this question by examining zonal variations in surface energy fluxes and dynamics governing tropical upper ocean heat content evolution in the WCRP CMIP5 model projections. There is some diversity among model simulations; for example, the CCSM4 indicates net ocean warming over the IndoPacific region while the CSIRO model concentrates separate warming responses over the central Pacific and Indian Ocean regions. The models, as with observations, demonstrate strong local coupling between variations in column water vapor, downward surface longwave radiation and SST; but the spatial patterns of changes in the sign of this relationship differ among models and, for models as a whole, with

  19. DNA evolved to minimize frameshift mutations

    OpenAIRE

    Agoni, Valentina

    2013-01-01

    Point mutations can surely be dangerous but what is worst than to lose the reading frame?! Does DNA evolved a strategy to try to limit frameshift mutations?! Here we investigate if DNA sequences effectively evolved a system to minimize frameshift mutations analyzing the transcripts of proteins with high molecular weights.

  20. Modelo experimental de tumor na cavidade oral de ratos com carcinossarcoma de Walker 256 Experimental model of Walker 256 carcinosarcoma developed in the oral cavity of rats

    Directory of Open Access Journals (Sweden)

    Ana Paula Negreiros Nunes Alves

    2004-08-01

    Full Text Available OBJETIVO: Estabelecer um modelo experimental de desenvolvimento tumoral na cavidade oral de ratos, permitindo, assim, o estudo da osteólise induzida pelo tumor nos ossos do complexo maxilomandibular como também nas estruturas dentais, através da caracterização histomorfológica da reabsorção óssea e dentária. MÉTODOS: Uma suspensão de células tumorais (0,1mL do Carcinossarcoma de Walker 256, na concentração de 10(6 células/mL foi implantado na cavidade alveolar de ratos previamente aberta por exodontia. Os animais foram observados durante 12 (doze dias consecutivos para determinação da curva de peso corpóreo, sendo posteriormente sacrificados e as mandíbulas removidas para exames radiográfico e histológico. RESULTADOS: No exame radiográfico foi verificada área lítica, sem evidência de reparo, na região dos alvéolos. No exame microscópico foi identificada infiltração óssea, periférica e central, de pequenas células hipercromáticas e pleomórficas, com leve infiltrado inflamatório mononuclear associado e áreas de necrose. O índice de pega foi de 100%. CONCLUSÃO: O modelo animal de invasão óssea, do tumor de Walker na cavidade oral, possibilita a avaliação in vivo de drogas antitumorais e esquemas terapêuticos no tratamento do câncer bucal.PURPOSE: To estabilish an experimental model of tumor development in the oral cavity of rats, that would enable to study the tumor-induced autolysis in the maxillomandibular bone complex as well as of the dental structures, through histomorphological characterization of bone and dental resorption. METHODS: Walker 256 carcinossarcoma cell suspension (0,1 mL containing 10(6 cell/mL was implanted in the alveoli of first and second molars. The animals were observed during twelve consecutive days and the body weigth were determined. Later, the animals were sacrificed and their mandibles removed to radiographic and hystologic analysis. RESULTS: The radiographic image

  1. Random walks with long-range steps generated by functions of Laplacian matrices

    OpenAIRE

    Riascos, A. P.; Michelitsch, T. M.; Collet, B. A.; Nowakowski, A. F.; Nicolleau, F. C. G. A

    2017-01-01

    In this paper, we explore different Markovian random walk strategies on networks with transition probabilities between nodes defined in terms of functions of the Laplacian matrix. We generalize random walk strategies with local information in the Laplacian matrix, that describes the connections of a network, to a dynamics determined by functions of this matrix. The resulting processes is non-local allowing transitions of the random walker from one node to nodes beyond its nearest neighbors. I...

  2. Robust spinal neuroinflammation mediates mechanical allodynia in Walker 256 induced bone cancer rats

    Directory of Open Access Journals (Sweden)

    Mao-Ying Qi-Liang

    2012-05-01

    Full Text Available Abstract It has been reported that remarkable and sustained activation of astrocytes and/or microglia occurs in cancer induced pain (CIP, which is different from neuropathic and inflammatory pain. The present study was designed to investigate the role of spinal Toll-like receptor 4 (TLR4 induced glial neuroinflammation in cancer induced pain using a modified rat model of bone cancer. The rat model of CIP consisted of unilateral intra-tibial injection with Walker 256 mammary gland carcinoma. Nine days after Walker 256 inoculation, a robust activation of both astrocytes and microglia in bilateral spinal dorsal horn was observed together with significant bilateral mechanical allodynia. This neuroinflammation was characterized by enhanced immunostaining of both glial fibrillary acidic protein (GFAP, astrocyte marker and OX-42 (microglia marker, and an elevated level of IL-1β, IL-6 and TNF-α mRNA. I.t. administration of fluorocitrate (an inhibitor of glial metabolism, 1 nmol or minocycline (an inhibitor of microglia, 100 μg has significant anti-allodynic effects on day 12 after Walker 256 inoculation. Naloxone (a nonstereoselective TLR4 signaling blocker, 60 μg, i.t. also significantly alleviated mechanical allodynia and simultaneously blocked the increased inflammatory cytokine mRNA. The results suggested that spinal TLR4 might play an important role in the sustained glial activation that critically contributed to the robust and sustained spinal neuroinflammation in CIP. This result could potentially help clinicians and researchers to better understand the mechanism of complicated cancer pain.

  3. The influence of septal lesions on sodium and water retention induced by Walker 256 tumor

    Directory of Open Access Journals (Sweden)

    F. Guimarães

    1999-03-01

    Full Text Available In the course of studies on the effects of septal area lesions on neuroimmunomodulation and Walker 256 tumor development, it was observed that tumor-induced sodium and water retention was less marked in lesioned than in non-lesioned rats. In the present study possible mechanisms involved in this phenomenon were investigated. The experiments were performed in septal-lesioned (LW; N = 15 and sham-operated (SW; N = 7 8-week-old male Wistar rats, which received multifocal simultaneous subcutaneous (sc inoculations of Walker 256 tumor cells about 30 days after the stereotaxic surgery. Control groups (no tumor, sham-operated food-restricted (SFR, N = 7 and lesioned food-restricted (LFR, N = 10 were subjected to a feeding pattern similar to that observed in tumor-bearing animals. Multifocal inoculation of Walker 256 tumor rapidly induces anorexia, which is paradoxically accompanied by an increase in body weight, as a result of renal Na+ and fluid retention. These effects of the tumor were also seen in LW rats, although the rise in fractional sodium balance during the early clinical period was significantly smaller than in SW rats (day 4: SW = 47.6 ± 6.4% and LW = 13.8 ± 5.2%; day 5: SW = 57.5 ± 3.5% and LW = 25.7 ± 4.8%; day 6: SW = 54.4 ± 3.8% and LW = 32.1 ± 4.4%; P<0.05, suggesting a temporary reduction in tumor-induced sodium retention. In contrast, urine output was significantly reduced in SW rats and increased in LW rats (LW up to -0.85 and SW up to 4.5 ml/100 g body weight, with no change in osmolar excretion. These temporary changes in the tumor's effects on LW rats may reflect a "reversal" of the secondary central antidiuretic response induced by the tumor (from antidiuretic to diuretic.

  4. Baby walker injury, disability, and death in a high-income middle eastern country, as reported by siblings.

    Science.gov (United States)

    Barss, Peter; Grivna, Michal; Al-Hanaee, Amna; Al-Dhahab, Ayesha; Al-Kaabi, Fatima; Al-Muhairi, Shamma

    2016-12-01

    Baby walkers (BWs) are frequent causes of infant injuries. Little research is reported from the Middle East and few population-based studies anywhere. Using multistage random sampling in a city of the United Arab Emirates, 4 of 8 female Arab government high schools and 3 final-year classes each from science and arts tracks were selected. Structured self-administered questionnaires assessed prevalence, frequency, severity, and external causes of BW incidents and injuries, and residential hazards. Response was 100 %, 696 students, 55 % (n = 385) Emirati citizens. 87 % (n = 605) of families used/had used BWs. Among 646 injuries were 118 ER (emergency) visits, 42 hospitalizations, 11 disabilities, and 3 deaths. Average risk was 1 incident/user, 1 injury/4 users, 1 ER visit/20, 1 hospitalization/55, 1 disability/200, 1 death/1000. Odds ratios for >1:1 floor levels were 2.3 (95 % confidence interval: 1.2, 4.3) for hospitalization, 16.8 (95 % CI: 2.1, 132.5) disability. Incidents included hitting objects 48 % (n = 1322), overturning 23 % (n = 632), accessing hazardous objects 17 % (n = 473), and falling down stairs 11 % (n = 300); 1 % (n = 32) fell into swimming pools. In 49 % (n = 297/605) of user families, ≥1 child had been injured. Despite causing many injuries including disabilities and fatalities, BWs were used by nearly all families. Governments should consider Canada's lead in prohibiting importation, sales, and advertising of BWs.

  5. Random walk centrality for temporal networks

    Science.gov (United States)

    Rocha, Luis E. C.; Masuda, Naoki

    2014-06-01

    Nodes can be ranked according to their relative importance within a network. Ranking algorithms based on random walks are particularly useful because they connect topological and diffusive properties of the network. Previous methods based on random walks, for example the PageRank, have focused on static structures. However, several realistic networks are indeed dynamic, meaning that their structure changes in time. In this paper, we propose a centrality measure for temporal networks based on random walks under periodic boundary conditions that we call TempoRank. It is known that, in static networks, the stationary density of the random walk is proportional to the degree or the strength of a node. In contrast, we find that, in temporal networks, the stationary density is proportional to the in-strength of the so-called effective network, a weighted and directed network explicitly constructed from the original sequence of transition matrices. The stationary density also depends on the sojourn probability q, which regulates the tendency of the walker to stay in the node, and on the temporal resolution of the data. We apply our method to human interaction networks and show that although it is important for a node to be connected to another node with many random walkers (one of the principles of the PageRank) at the right moment, this effect is negligible in practice when the time order of link activation is included.

  6. Global surgery formula for the Casson-Walker invariant (AM-140)

    CERN Document Server

    Lescop, Christine

    2014-01-01

    This book presents a new result in 3-dimensional topology. It is well known that any closed oriented 3-manifold can be obtained by surgery on a framed link in S 3. In Global Surgery Formula for the Casson-Walker Invariant, a function F of framed links in S 3 is described, and it is proven that F consistently defines an invariant, lamda (l), of closed oriented 3-manifolds. l is then expressed in terms of previously known invariants of 3-manifolds. For integral homology spheres, l is the invariant introduced by Casson in 1985, which allowed him to solve old and famous questions in 3-dimensional

  7. Maternal grand mal seizure leads to a surprising diagnosis of Dandy-Walker variant.

    Science.gov (United States)

    Mendelson, Sherri G

    2011-01-01

    Pregnant women may present with abnormal symptoms that are assumed to be related to the pregnancy. The purpose of this case study is to examine an obstetric case that provides a wider view of a grand mal seizure in a perinatal patient with previously undiagnosed Dandy-Walker Variant. When a pregnant or newly postpartum woman has seizures, eclampsia may be the most the most likely diagnosis, but it may not be accurate. © 2011 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

  8. PET/CT in a Patient Diagnosed With Dandy-Walker Syndrome.

    Science.gov (United States)

    Infante, Jose R; Garcia, Lucia; Rayo, Juan I; Serrano, Justo; Dominguez, Maria L; Moreno, Manuel

    2016-01-01

    The Dandy-Walker syndrome (DWS) is a rare congenital posterior fossa malformation characterized by aplasia or hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa. We present a 52-year-old Caucasian man diagnosed with gastrointestinal stromal tumor and submitted to 18F-FDG PET/CT as a staging procedure. The patient was previously diagnosed with DWS in brain CT scan. PET/CT images revealed an ametabolic large cyst in the posterior fossa and hypoplasia of cerebellar vermis. The case is presented with the aim to show the appearance of this syndrome on PET/CT study.

  9. Dandy Walker Syndrome with Unusual Associated Findings in a Fetal Autopsy Study

    Directory of Open Access Journals (Sweden)

    Surekha U Arakeri

    2015-01-01

    Full Text Available Dandy Walker Syndrome (DWS is a congenital brain malformation characterized by hypoplasia or absence of cerebellar vermis, cystic dilatation of fourth ventricle and hydrocephalus. It is frequently associated with other congenital anomalies. Associated central nervous system anomalies such as agenesis of corpus callosum and vermis are associated with poor prognosis. Association of DWS with congenital absence of spleen is life threatening condition and has been reported very rarely. Autopsy findings of DWS with association of congenital absence of corpus callosum, vermis and spleen are reported in a stillborn fetus of 28 weeks gestation and review of relevant literature was done

  10. Very severe spinal muscular atrophy: Type 0 with Dandy-Walker variant.

    Science.gov (United States)

    Gathwala, Geeta; Silayach, Joginder; Bhakhari, Bhanu Kiran; Narwal, Varun

    2014-01-01

    Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by degeneration of alpha motor neurons in the spinal cord, resulting in progressive proximal muscle weakness and paralysis. In addition to the three classical SMA types, a new form known as type 0 with intrauterine onset, profound hypotonia and a progressive and early fatal course has been described. Herein we report a case of type 0 SMA with a Dandy Walker variant anomaly, which has not hitherto been reported in the world literature.

  11. Dandy–Walker syndrome with duplex kidney abnormalities in trisomy 18 – A rare case report

    Directory of Open Access Journals (Sweden)

    Tun-Jun Wang

    2017-10-01

    We report a case involving a 39-year-old pregnant female with a case of trisomy 18 associated with Dandy–Walker malformation (DWM. Fetal ultrasonography showed hypoplasia of the cerebellar vermis and dilatation of the fourth ventricle and was characterized by an enlarged posterior fossa. Fetal magnetic resonance imaging showed inferior vermian hypoplasia and a large posterior fossa cyst communicating with the fourth ventricle causing high insertion of the torcular herophili, which was compatible with DWM. Furthermore, the karyotyping report revealed trisomy 18. The incidence of trisomy 18 associated with DWM is rare, and our report presents an unusual case that supplements our knowledge of this condition.

  12. Central diabetes insipidus, central hypothyroidism, renal tubular acidosis and dandy-walker syndrome: new associations.

    Science.gov (United States)

    Alafif, M M; Aljaid, S S; Al-Agha, A E

    2015-01-01

    Dandy-Walker syndrome (DWS) is a rare brain malformation involving the cerebellum, and the fluid filled spaces around it, usually detected during the antenatal period or the early infancy. Clinically, it is characterized by mental retardation, developmental delay as well as cerebellar ataxia. It has been frequently associated with other conditions such as congenital heart diseases, primary hypothyroidism, and other disorders of the central nervous, gastrointestinal, genitourinary, and orthopedic systems. In this report, we describe a 3-month-old Saudi boy with the rare association of DWS with central diabetes insipidus, congenital central hypothyroidism, and type-2 renal tubular acidosis.

  13. On the scalar particle creation by electromagnetic fields in Robertson–Walker spacetime

    Directory of Open Access Journals (Sweden)

    Kenan Sogut

    2015-12-01

    Full Text Available In the present paper, we obtained the scalar particle creation number density by using the Klein–Gordon equation coupled to the electromagnetic fields in the Robertson–Walker spacetime with the help of the Bogoliubov transformation method. We analyzed the resulting expression for the effect of a time-dependent electric field and a constant magnetic field on the particle production rate and found that the strong time-dependent electric field amplifies the particle creation and the magnetic field reduces the rate, in accordance with the previous findings.

  14. WSC-07: Evolving the Web Services Challenge

    NARCIS (Netherlands)

    Blake, M. Brian; Cheung, William K.W.; Jaeger, Michael C.; Wombacher, Andreas

    Service-oriented architecture (SOA) is an evolving architectural paradigm where businesses can expose their capabilities as modular, network-accessible software services. By decomposing capabilities into modular services, organizations can share their offerings at multiple levels of granularity

  15. Satcom access in the evolved packet core

    NARCIS (Netherlands)

    Cano, M.D.; Norp, A.H.J.; Popova, M.P.

    2012-01-01

    Satellite communications (Satcom) networks are increasingly integrating with terrestrial communications networks, namely Next Generation Networks (NGN). In the area of NGN the Evolved Packet Core (EPC) is a new network architecture that can support multiple access technologies. When Satcom is

  16. Acquisition: Acquisition of the Evolved SEASPARROW Missile

    National Research Council Canada - National Science Library

    2002-01-01

    .... The Evolved SEASPARROW Missile, a Navy Acquisition Category II program, is an improved version of the RIM-7P SEASPARROW missile that will intercept high-speed maneuvering, anti-ship cruise missiles...

  17. Cyberspace Operations: Influence Upon Evolving War Theory

    Science.gov (United States)

    2011-03-18

    St ra te gy R es ea rc h Pr oj ec t CYBERSPACE OPERATIONS: INFLUENCE UPON EVOLVING WAR THEORY BY COLONEL KRISTIN BAKER United States...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Cyberspace Operations: Influence Upon Evolving War Theory 5a. CONTRACT NUMBER... Leadership 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S

  18. Evolving effective incremental SAT solvers with GP

    OpenAIRE

    Bader, Mohamed; Poli, R.

    2008-01-01

    Hyper-Heuristics could simply be defined as heuristics to choose other heuristics, and it is a way of combining existing heuristics to generate new ones. In a Hyper-Heuristic framework, the framework is used for evolving effective incremental (Inc*) solvers for SAT. We test the evolved heuristics (IncHH) against other known local search heuristics on a variety of benchmark SAT problems.

  19. Evolved Control of Natural Plants: Crossing the Reality Gap for User-Defined Steering of Growth and Motion

    DEFF Research Database (Denmark)

    Hofstadler, Daniel Nicolas; Wahby, Mostafa; Heinrich, Mary Katherine

    2017-01-01

    in response to the simple controller is captured by image processing, and a model of the plant tip dynamics is developed. The model is used in simulation to evolve a robot controller that steers the plant tip such that it follows a number of randomly generated target points. Finally, we test the simulation-evolved...

  20. The oophorectomy effect on Walker 256 tumor inoculated into the vagina and uterine cervix of female rats Efeito da ooforectomia no tumor de Walker 256 inoculado em vagina e colo de útero de ratos fêmeas

    Directory of Open Access Journals (Sweden)

    Nara Macedo Botelho Brito

    2009-02-01

    Full Text Available PURPOSE: Verify the effect of oophorectomy on the evolution of the Walker 256 tumor inoculated into the vagina and cervix of female rats. METHODS: Ten Wistar, female rats were used, distributed into two groups with 05 animals each: Tumor group (TG: Rats inoculated with Walker 256 tumor; Oophorectomy group (OG: oophorectomized rats inoculated with Walker 256 tumor. The day before the tumor vaginal inoculation, acetic acid was inoculated into the vaginas of both groups of rats; the following day, the vaginal walls were scarified with an endocervix brush, and then Walker 256 tumor was inoculated. After 12 days, the tumor was removed together with the vagina and uterine horns for macro and microscopic analyses. The data were submitted to statistical analyses. RESULTS: There was no statistical difference between the two groups; however it was observed that the behavior of tumor growth on the OG group presented greater invasion, compromising the uterine horns. CONCLUSION: The results of the study on the GO group presented a macroscopic behavior different from the TG group, however, both of them presented similar development in terms of tumor mass.OBJETIVO: Verificar o efeito da ooforectomia à inoculação do tumor de Walker 256 em vagina e colo de útero de ratas. MÉTODOS: Foram utilizadas 10 ratas Wistar, fêmeas, virgens, adultas, distribuídas em dois grupos de estudo com 05 animais cada: grupo tumor (GT: ratas inoculadas com tumor de Walker 256, e grupo Ooforectomia (GO: ratas ooforectomizadas e inoculadas com tumor de Walker 256. No dia anterior à inoculação vaginal do tumor, foram inoculados 0,3ml de ácido acético na vagina das ratas de ambos os grupos; no dia seguinte, foi realizada a escarificação da parede vaginal com uma escova de endocérvice e inoculado tumor de Walker 256. Após 12 dias, foi removido o tumor em bloco com vagina e cornos uterinos para análise macro e microscópica. Os dados foram submetidos à análise estat

  1. Analysis of the genetic diversity in Metopolophium dirhodum (Walker (Hemiptera, Aphididae by RAPD markers Análise da diversidade genética de Metopolophium dirhodum (Walker (Hemiptera, Aphididae por meio de marcadores RAPD

    Directory of Open Access Journals (Sweden)

    Marcelo Lopes-da-Silva

    2007-03-01

    Full Text Available The emergence of host-races within aphids may constitute an obstacle to pest management by means of plant resistance. There are examples of host-races within cereals aphids, but their occurrence in Rose Grain Aphid, Metopolophium dirhodum (Walker, 1849, has not been reported yet. In this work, RAPD markers were used to assess effects of the hosts and geographic distance on the genetic diversity of M. dirhodum lineages. Twenty-three clones were collected on oats and wheat in twelve localitites of southern Brazil. From twenty-seven primers tested, only four primers showed polymorphisms. Fourteen different genotypes were revealed by cluster analysis. Five genotypes were collected only on wheat; seven only on oats and two were collected in both hosts. Genetic and geographical distances among all clonal lineages were not correlated. Analysis of molecular variance showed that some molecular markers are not randomly distributed among clonal lineages collected on oats and on wheat. These results suggest the existence of host-races within M. dirhodum, which should be further investigated using a combination of ecological and genetic data.A emergência de raças hospedeiro-especialistas em afídeos pode constituir um obstáculo ao manejo de pragas por meio de plantas resistentes. Existem exemplos de raças hospedeiro-especialistas em afídeos de cereais, embora a ocorrência de raça hospedeiro-especialista no pulgão-verde-pálido-do-trigo Metopolophium dirhodum (Walker, 1849 (Hemiptera, Aphididae não tenha sido relatada ainda. Marcadores RAPD foram utilizados para avaliar os efeitos da distância geográfica e do hospedeiro sobre a diversidade genética de linhas clonais de M. dirhodum. Vinte e três clones foram coletados em aveia e trigo em doze localidades do sul do Brasil. De vinte e sete iniciadores usados para a análise, apenas quatro iniciadores mostraram polimorfismos. A análise de agrupamento por similaridade genética revelou haver quatorze

  2. Fallot Pentalojisi’nin eşlik ettiği Dandy-Walker varyasyonu: Olgu sunumu

    OpenAIRE

    Güven, Ahmet; Oflaz, Mehmet; Kaya, Ali; Bolat, Fatih; Gülsever, Osman; Şalk, İsmail; Bozoklu Akkar, Özlem; İçağasıoğlu, Füsun

    2014-01-01

    ÖzetDandy-Walker varyasyonu, 4. ventrikül ve sisterna magna arasındaki devamlılıkla sonuçlanan vermisin parsiyel agenezisi ile karakterize santral sinir sisteminin nadir bir anomalisidir. Literatürde ilk kez 1988’de Kohyama ve arkadaşları tarafından bildirilen Dandy-Walker varyasyonu ve Fallot Tetralojisi birlikteliği daha sonraki yıllarda birkaç vaka sunumu şeklinde bildirilmiştir. Biz bu yazıda, Dandy-Walker varyasyonu ve Fallot Pentalojisi olan 2 günlük bir erkek hastayı bildiriyoruz.Anaht...

  3. Random Multi-Hopper Model. Super-Fast Random Walks on Graphs

    OpenAIRE

    Estrada, Ernesto; Delvenne, Jean-Charles; Hatano, Naomichi; Mateos, José L.; Metzler, Ralf; Riascos ( Universidad Mariana, Pasto, Colombia), Alejandro P; Schaub, Michael T.

    2016-01-01

    We develop a model for a random walker with long-range hops on general graphs. This random multi-hopper jumps from a node to any other node in the graph with a probability that decays as a function of the shortest-path distance between the two nodes. We consider here two decaying functions in the form of the Laplace and Mellin transforms of the shortest-path distances. Remarkably, when the parameters of these transforms approach zero asymptotically, the multi-hopper's hitting times between an...

  4. Analysis of growth directions of columnar stromatolites from Walker Lake, western Nevada.

    Science.gov (United States)

    Petryshyn, V A; Corsetti, F A

    2011-09-01

    Samples of digitate, branching, columnar stromatolites were collected from the steep sides and near horizontal top of four in situ boulders located on the southwestern side of Walker Lake, Nevada, to test the widely held assumption that stromatolite column formation represents a phototropic response. We would predict that the columns on the steeply dipping sides of the boulder would bend upwards toward the light during growth if phototropism was significant during stromatolite morphogenesis. Angle of growth measurements on >300 stromatolites demonstrate that the stromatolites grew nearly normal to their growth surface, regardless of the inclination of their growth surface. No significant differences in the distribution of growth angles between north-, south-, east-, or west-facing samples were observed, and stromatolite lamina thickness did not systematically vary with position on the boulder. The lack of a strong phototropic response does not rule out a biological origin for the Walker Lake structures, but it does suggest that phototropic growth was not a dominant factor controlling stromatolite morphogenesis in these stromatolites and that column formation cannot be uniquely attributed as a phototropic response in stromatolites. It is interesting to note that the morphology of the stromatolites on the top of the boulder is identical to stromatolites on the steep sides. Stromatolite morphogenetic models that predict branching typically require a vertically directed sedimentary component, a feature that would have likely affected the stromatolites on the tops of the boulders, but not the sides, suggesting that other factors may be important in stromatolite morphogenesis. © 2011 Blackwell Publishing Ltd.

  5. A biological walker is faster and better recognized when aligned with body axis observer.

    Science.gov (United States)

    Barbieri, Guillaume; Fouque, Florent; Pozzo, Thierry; Pérennou, Dominic

    2013-09-01

    The representation of the vertical direction is a compromise between the directions given by the egocentric and allocentric references. Dissociations between these two referentials in the discrimination of a biological walker which typically refers to a model of verticality questions the coordinate system (allocentric and/or egocentric) used to perceive it. With a point-light display paradigm, the characteristics of an artificial walking pattern were manipulated in order to offer to 10 healthy participants (5 men/5 women; 24.6±3.4 years) a female or male locomotion which had to be identified as such. The body position of the viewer (sitting/lying) and the walking pattern viewed (aligned/rotated in relation to the egocentric referential) were crossed. Three indices were analyzed and 200 trials recorded: percentage of correct identification, reaction time and confidence score. This paper confirms the validity of the walking pattern model since the more pronounced the gradient of the walking pattern (as female or male) the better the recognition. Furthermore, whatever the body position, artificial walking patterns were more easily identified when they were aligned with the egocentric referential rather than tilted. The participant gender had no influence on the walking pattern recognition. We conclude that the perception of a biological walker referenced to the vertical is exclusively improved by a representation of the spatial information in an egocentric coordinate system. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Preliminary stability analysis of a Friedman-Lemaitre-Robertson-Walker universe

    Science.gov (United States)

    Yahalom, Asher

    2017-05-01

    It is stated in many text books that the any metric appearing in general relativity should be locally Lorentzian i.e. of the type gµν = diag (1, -1, -1, -1) this is usually presented as an independent axiom of the theory, which cannot be deduced from other assumptions. The meaning of this assertion is that a specific coordinate (the temporal coordinate) is given a unique significance with respect to the other spatial coordinates. It was shown that the above assertion is a consequence of requirement that the metric of empty space should be linearly stable and need not be assumed. In this work we remove the empty space assumption and investigate the consequences of spatially uniform matter on the stability of a locally Lorentzian space-time that is the Friedman-Lemaitre-Robertson-Walker space-time. It is shown that a partial stability analysis restricts the type of allowable solutions to the Friedman-Lemaitre-Robertson-Walker space-time. In particular it is shown that an open section universe is stable while an Euclidean and a closed section universes are not in accordance with observation. It will be suggested that in the presence of matter an upper limit scale to the size of a locally Lorentzian universe exists which incidentally is about the size of the observable universe.

  7. A class of almost equilibrium states in Robertson-Walker spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Kueskue, Muharrem

    2008-11-06

    In quantum field theory in curved spacetimes the construction of the algebra of observables of linear fields is today well understood. However, it remains a non-trivial task to construct physically meaningful states on the algebra. For instance, we are in the unsatisfactory situation that there exist no examples of states suited to describe local thermal equilibrium in a non-stationary spacetime. In this thesis, we construct a class of states for the Klein-Gordon field in Robertson-Walker spacetimes, which seem to provide the first example of thermal states in a spacetime without time translation symmetry. More precisely, in the setting of real, linear, scalar fields in Robertson-Walker spacetimes we define on the set of homogeneous, isotropic, quasi-free states a free energy functional that is based on the averaged energy density measured by an isotropic observer along his worldline. This functional is well defined and lower bounded by a suitable quantum energy inequality. Subsequently, we minimize this functional and obtain states that we interpret as 'almost equilibrium states'. It turns out that the states of low energy are the ground states of the almost equilibrium states. Finally, we prove that the almost equilibrium states satisfy the Hadamard condition, which qualifies them as physically meaningful states. (orig.)

  8. Recent Walker circulation strengthening and Pacific cooling amplified by Atlantic warming

    Science.gov (United States)

    McGregor, Shayne; Timmermann, Axel; Stuecker, Malte F.; England, Matthew H.; Merrifield, Mark; Jin, Fei-Fei; Chikamoto, Yoshimitsu

    2014-10-01

    An unprecedented strengthening of Pacific trade winds since the late 1990s (ref. ) has caused widespread climate perturbations, including rapid sea-level rise in the western tropical Pacific, strengthening of Indo-Pacific ocean currents, and an increased uptake of heat in the equatorial Pacific thermocline. The corresponding intensification of the atmospheric Walker circulation is also associated with sea surface cooling in the eastern Pacific, which has been identified as one of the contributors to the current pause in global surface warming. In spite of recent progress in determining the climatic impacts of the Pacific trade wind acceleration, the cause of this pronounced trend in atmospheric circulation remains unknown. Here we analyse a series of climate model experiments along with observational data to show that the recent warming trend in Atlantic sea surface temperature and the corresponding trans-basin displacements of the main atmospheric pressure centres were key drivers of the observed Walker circulation intensification, eastern Pacific cooling, North American rainfall trends and western Pacific sea-level rise. Our study suggests that global surface warming has been partly offset by the Pacific climate response to enhanced Atlantic warming since the early 1990s.

  9. Anestesia em criança com síndrome de Walker-Warburg

    Directory of Open Access Journals (Sweden)

    Emine Arzu Kose

    2014-04-01

    Full Text Available Justificativa e objetivos: A síndrome de Walker-Warburg é uma distrofia muscular autossômica recessiva congênita rara, manifestada pelo sistema nervoso central com malformações oculares e possível envolvimento de vários sistemas. O diagnóstico é estabelecido pela presença de quatro critérios: distrofia muscular congênita, lisencefalia tipo II, malformação cerebelar e malformação da retina. A maioria das crianças com a síndrome morre nos primeiros três anos de vida por causa de insuficiência respiratória, pneumonia, convulsões, hipertermia e fibrilação ventricular. Relato de caso: É discutida a conduta anestésica em uma criança do sexo masculino, de dois meses, programada para cirurgia eletiva de derivação ventrículo-peritoneal. Conclusões: Uma abordagem anestésica cuidadosa é necessária por causa do envolvimento de vários sistemas. Relatamos a conduta anestésica em uma criança do sexo masculino de dois meses com síndrome de Walker-Warburg, que foi programada para cirurgia eletiva de derivação ventrículo-peritoneal.

  10. An anxiety-induced bias in the perception of a bistable point-light walker.

    Science.gov (United States)

    Van de Cruys, Sander; Schouten, Ben; Wagemans, Johan

    2013-11-01

    Human sensitivity for social cues is exquisite, as illustrated by the ease with which simplified point-light movements invoke social and emotional responses. Compared to faces, these biological motion stimuli only recently started to be used to explore questions regarding social cognition and anxiety. We presented human point-light walkers that could be perceived as facing towards or facing away from the observer, and tested whether participants with high social anxiety would perceive these bistable stimuli differently, because this type of stimuli has particular relevance for them. The results showed that observers with high social anxiety tended to see walkers as facing away more frequently than those with low social anxiety. This may mean that high socially anxious observers are biased towards the more positive perceptual alternative because they are motivated to protect themselves against threatening social experiences, but we also explore alternative explanations. The findings are in line with the evidence for a positivity bias in perception, also called wishful seeing, but in contrast with the attentional negativity bias often found in social anxiety. We discuss reasons for this divergence and possible limitations of the current study. © 2013.

  11. The Most Common Comorbidities in Dandy-Walker Syndrome Patients: A Systematic Review of Case Reports.

    Science.gov (United States)

    Stambolliu, Emelina; Ioakeim-Ioannidou, Myrsini; Kontokostas, Kimonas; Dakoutrou, Maria; Kousoulis, Antonis A

    2017-09-01

    Dandy-Walker syndrome (DWS) is a rare neurologic multi-entity malformation. This review aimed at reporting its main nonneurologic comorbidities. Following PRISMA guidelines, search in Medline was conducted (2000-2014, keyword: dandy-walker). Age, sex, country, DWS type, consanguinity or siblings with DWS, and recorded coexistent conditions (by ICD10 category) were extracted for 187 patients (46.5% male, 43% from Asia) from 168 case reports. Diagnosis was most often set in 12 years old (27.8%). One-third of cases had a chromosomal abnormality or syndrome (n = 8 PHACE), 27% had a cardiovascular condition (n = 7 Patent Ductus Arteriosus), 24% had a disease of eye and ear (n = 9 cataract); most common malignancy was nephroblastoma (n = 8, all Asian). Almost one-fifth had a mental illness diagnosis; only 6.4% had mild or severe intellectual disability. The spread of comorbidities calls for early diagnosis and multidisciplinary research and practice, especially as many cases remain clinically asymptomatic for years.

  12. Neurocutaneous melanosis and the Dandy-Walker complex: an uncommon but not so insignificant association.

    Science.gov (United States)

    Marnet, Dominique; Vinchon, Matthieu; Mostofi, Keyvan; Catteau, Benoit; Kerdraon, Olivier; Dhellemmes, Patrick

    2009-12-01

    Neurocutaneous melanosis represents a rare congenital but nonheritable phakomatosis defined as the association of giant or multiple congenital nonmalignant melanocytic nevi with leptomeningeal melanosis or melanoma of the central nervous system. We describe the case of an adolescent with a giant congenital bathing trunk melanocytic nevus who developed progressive intracranial hypertension due to leptomeningeal melanosis confirmed by surgical biopsy. Brain and spine magnetic resonance images showed posterior fossa malformation compatible with the Dandy-Walker complex, hydrocephalus, and extensive enhancement of posterior fossa then spine. Shunt placement, corticotherapy, and chemotherapy were attempted leading to transient relief but the boy died 12 months after the onset of primary neurological symptoms. We discuss diagnosis, pathogenesis, management, and prognosis in the light of data from the recent literature. Neurocutaneous melanosis is considered to follow from neurulation disorders which could account for associated developmental malformations as the so-called Dandy-Walker complex. Cutaneous lesions are usually recognized at birth whereas neurological manifestations develop later. Numerous neurological symptoms have been reported according to extent of leptomeningeal and parenchymal infiltration. Whether magnetic resonance imaging of the neuroaxis represents the choice radiological exam, definite diagnosis relies upon the histological data obtained by mean of biopsy. Once symptomatic, surgical and medical measures remain palliative since death occurs within 3 years.

  13. Dandy–Walker malformation is a rare cause of syringomyelia in adults

    Directory of Open Access Journals (Sweden)

    G. Yu. Evzikov

    2017-01-01

    Full Text Available Neural tube defects are the most common central nervous system malformation. Dandy–Walker malformation (DWM is a rare abnormality of the posterior cranial fossa, which is generally diagnosed in the prenatal period or early infancy.The paper describes a case of the late clinical manifestation of DWM, which has caused syringomyelia. All variants of pathological changes within the Dandy–Walker complex very rarely become a cause of syringomyelia. Only four cases of DWM, in which syringomyelia was found in adults, are known.The authors believe that formation of syringomyelia cysts in these patients is associated with the impaired circulation of normal cerebrospinal fluid between the superior cistern and the subarachnoid spaces of the spinal cord due to the caudal dislocation of the cyst formed in the fourth ventricle.Decompression of the craniovertebral junction, by resecting the caudal portion of the cyst in the foramen magnum, and repair of the free communication between the superior cistern and the cerebrospinal fluid spaces of the spinal cord, which is complemented by duroplasty, are pointed out to be an optimal treatment in these patients.

  14. Dandy-Walker syndrome with duplex kidney abnormalities in trisomy 18 - A rare case report.

    Science.gov (United States)

    Wang, Tun-Jun; Li, Yi-Ying; Wu, Wan-Ju; Lin, Chi-Kang; Wang, Chun-Kai; Wang, Chen-Yu; Hwang, Kwei-Shuai; Su, Her-Young

    2017-10-01

    Trisomy 18 is one of the major numerical chromosomal disorders. The incidence of trisomy 18 is approximately one in 6000 live births. Dandy-Walker malformation (DWM) is the most common congenital malformation of the cerebellum, with an incidence of about one in 5000 live births. The incidence of trisomy 18 associated with DWM is rare and long-term survival rate is very low. A case involving a 39-year-old pregnant female with a case of trisomy 18 associated with DWM. The incidence of trisomy 18 associated with DWM is rare, and our report presents an unusual case that supplements our knowledge of this condition. We report a case involving a 39-year-old pregnant female with a case of trisomy 18 associated with Dandy-Walker malformation (DWM). Fetal ultrasonography showed hypoplasia of the cerebellar vermis and dilatation of the fourth ventricle and was characterized by an enlarged posterior fossa. Fetal magnetic resonance imaging showed inferior vermian hypoplasia and a large posterior fossa cyst communicating with the fourth ventricle causing high insertion of the torcular herophili, which was compatible with DWM. Furthermore, the karyotyping report revealed trisomy 18. The incidence of trisomy 18 associated with DWM is rare, and our report presents an unusual case that supplements our knowledge of this condition. Copyright © 2017. Published by Elsevier B.V.

  15. Dandy-Walker syndrome in adult mimicking myasthenia gravis Síndrome de Dandy-Walker em adulto simulando miastenia gravis

    Directory of Open Access Journals (Sweden)

    Juliana Cardoso

    2007-03-01

    Full Text Available The Dandy-Walker syndrome (DWS is a rare posterior fossa malformation. The DWS can occur associated with other brain or systemic malformations, but ocular abnormalities in this disease are rare and clinical findings mimicking myasthenia gravis have not been described to date. We report a 23-year-old woman who presented mild limitation of the ocular movements with progressive palpebral ptosis, which changed in intensity during the day. The investigation showed negative anti-acetylcholine receptor antibody, repetitive nerve stimulation and "Tensilon test", but the brain magnetic resonance image reveals DWS with hydrocephalus associated with calosal dysgenesis. The characteristic of disease, clinical manifestations and pathologic features, specially the clinical evaluation of ocular abnormalities in suspicion of DWS, including the MG in differential diagnosis are discussed.A síndrome de Dandy-Walker (DWS é uma rara malformação da fossa posterior que pode ocorrer associada com outras malformações cerebrais ou sistêmicas. As alterações oculares são raras e as manifestações clínicas, simulando miastenia gravis (MG, não foram descritas até o momento. Descrevemos uma mulher de 23 anos apresentando discreta limitação da movimentação ocular com progressiva ptose palpebral que mudava de intensidade durante o dia. A investigação mostrou negativos o anticorpo anti-receptor de acetilcolina, a estimulação nervosa repetitiva e o "teste do Tensilon", porém a ressonância magnética de crânio revelou DWS com hidrocefalia associada à disgenesia de corpo caloso. As características da doença, manifestações clínicas e patológicas, especialmente a avaliação clínica de anormalidade ocular na suspeita de DWS serão discutidas, incluindo a MG no diagnóstico diferencial.

  16. Evolvability Search: Directly Selecting for Evolvability in order to Study and Produce It

    DEFF Research Database (Denmark)

    Mengistu, Henok; Lehman, Joel Anthony; Clune, Jeff

    2016-01-01

    One hallmark of natural organisms is their significant evolvability, i.e.,their increased potential for further evolution. However, reproducing such evolvability in artificial evolution remains a challenge, which both reduces the performance of evolutionary algorithms and inhibits the study...... of evolvable digital phenotypes. Although some types of selection in evolutionary computation indirectly encourage evolvability, one unexplored possibility is to directly select for evolvability. To do so, we estimate an individual's future potential for diversity by calculating the behavioral diversity of its...... immediate offspring, and select organisms with increased offspring variation. While the technique is computationally expensive, we hypothesized that direct selection would better encourage evolvability than indirect methods. Experiments in two evolutionary robotics domains confirm this hypothesis: in both...

  17. Haruki Murakami’s Deconstructive Reading of the Myth of Johnnie Walker and Colonel Sanders in Kafka on the Shore

    Directory of Open Access Journals (Sweden)

    Limanta L. S.

    2012-01-01

    Full Text Available This study aims to analyze how Haruki Murakami reads the real icons of Johnnie Walker and Colonel Sanders in Kafka on the Shore deconstructively. First, we will focus on the signification process of the icon, which are to a great extent molded by advertisements, and then on the deconstruction of their signifieds. For the purpose, we will apply Barthes’ idea of myth. We are also interested in revealing how Murakami constructs Johnnie Walker and Colonel Sanders to be characters in the novel. The analysis shows that the construction of the icons through advertisements leads to the creation of their mtyhs, and then Murakami reads them deconstructively to be opposite signifieds.

  18. Mutations in extracellular matrix genes NID1 and LAMC1 cause autosomal dominant Dandy-Walker malformation and occipital cephaloceles.

    Science.gov (United States)

    Darbro, Benjamin W; Mahajan, Vinit B; Gakhar, Lokesh; Skeie, Jessica M; Campbell, Elizabeth; Wu, Shu; Bing, Xinyu; Millen, Kathleen J; Dobyns, William B; Kessler, John A; Jalali, Ali; Cremer, James; Segre, Alberto; Manak, J Robert; Aldinger, Kimerbly A; Suzuki, Satoshi; Natsume, Nagato; Ono, Maya; Hai, Huynh Dai; Viet, Le Thi; Loddo, Sara; Valente, Enza M; Bernardini, Laura; Ghonge, Nitin; Ferguson, Polly J; Bassuk, Alexander G

    2013-08-01

    We performed whole-exome sequencing of a family with autosomal dominant Dandy-Walker malformation and occipital cephaloceles and detected a mutation in the extracellular matrix (ECM) protein-encoding gene NID1. In a second family, protein interaction network analysis identified a mutation in LAMC1, which encodes a NID1-binding partner. Structural modeling of the NID1-LAMC1 complex demonstrated that each mutation disrupts the interaction. These findings implicate the ECM in the pathogenesis of Dandy-Walker spectrum disorders. © 2013 WILEY PERIODICALS, INC.

  19. Evolved atmospheric entry corridor with safety factor

    Science.gov (United States)

    Liang, Zixuan; Ren, Zhang; Li, Qingdong

    2018-02-01

    Atmospheric entry corridors are established in previous research based on the equilibrium glide condition which assumes the flight-path angle to be zero. To get a better understanding of the highly constrained entry flight, an evolved entry corridor that considers the exact flight-path angle is developed in this study. Firstly, the conventional corridor in the altitude vs. velocity plane is extended into a three-dimensional one in the space of altitude, velocity, and flight-path angle. The three-dimensional corridor is generated by a series of constraint boxes. Then, based on a simple mapping method, an evolved two-dimensional entry corridor with safety factor is obtained. The safety factor is defined to describe the flexibility of the flight-path angle for a state within the corridor. Finally, the evolved entry corridor is simulated for the Space Shuttle and the Common Aero Vehicle (CAV) to demonstrate the effectiveness of the corridor generation approach. Compared with the conventional corridor, the evolved corridor is much wider and provides additional information. Therefore, the evolved corridor would benefit more to the entry trajectory design and analysis.

  20. Interactively Evolving Compositional Sound Synthesis Networks

    DEFF Research Database (Denmark)

    Jónsson, Björn Þór; Hoover, Amy K.; Risi, Sebastian

    2015-01-01

    While the success of electronic music often relies on the uniqueness and quality of selected timbres, many musicians struggle with complicated and expensive equipment and techniques to create their desired sounds. Instead, this paper presents a technique for producing novel timbres that are evolved......, CPPNs can theoretically compute any function and can build on those present in traditional synthesizers (e.g. square, sawtooth, triangle, and sine waves functions) to produce completely novel timbres. Evolved with NeuroEvolution of Augmenting Topologies (NEAT), the aim of this paper is to explore...... the space of potential sounds that can be generated through such compositional sound synthesis networks (CSSNs). To study the effect of evolution on subjective appreciation, participants in a listener study ranked evolved timbres by personal preference, resulting in preferences skewed toward the first...

  1. Quantifying evolvability in small biological networks

    Energy Technology Data Exchange (ETDEWEB)

    Nemenman, Ilya [Los Alamos National Laboratory; Mugler, Andrew [COLUMBIA UNIV; Ziv, Etay [COLUMBIA UNIV; Wiggins, Chris H [COLUMBIA UNIV

    2008-01-01

    The authors introduce a quantitative measure of the capacity of a small biological network to evolve. The measure is applied to a stochastic description of the experimental setup of Guet et al. (Science 2002, 296, pp. 1466), treating chemical inducers as functional inputs to biochemical networks and the expression of a reporter gene as the functional output. The authors take an information-theoretic approach, allowing the system to set parameters that optimise signal processing ability, thus enumerating each network's highest-fidelity functions. All networks studied are highly evolvable by the measure, meaning that change in function has little dependence on change in parameters. Moreover, each network's functions are connected by paths in the parameter space along which information is not significantly lowered, meaning a network may continuously change its functionality without completely losing it along the way. This property further underscores the evolvability of the networks.

  2. Evolution of evolvability in gene regulatory networks.

    Directory of Open Access Journals (Sweden)

    Anton Crombach

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

  3. How the first biopolymers could have evolved.

    Science.gov (United States)

    Abkevich, V I; Gutin, A M; Shakhnovich, E I

    1996-01-01

    In this work, we discuss a possible origin of the first biopolymers with stable unique structures. We suggest that at the prebiotic stage of evolution, long organic polymers had to be compact to avoid hydrolysis and had to be soluble and thus must not be exceedingly hydrophobic. We present an algorithm that generates such sequences for model proteins. The evolved sequences turn out to have a stable unique structure, into which they quickly fold. This result illustrates the idea that the unique three-dimensional native structures of first biopolymers could have evolved as a side effect of nonspecific physicochemical factors acting at the prebiotic stage of evolution. PMID:8570645

  4. Evolving Intelligent Systems Methodology and Applications

    CERN Document Server

    Angelov, Plamen; Kasabov, Nik

    2010-01-01

    From theory to techniques, the first all-in-one resource for EIS. There is a clear demand in advanced process industries, defense, and Internet and communication (VoIP) applications for intelligent yet adaptive/evolving systems. Evolving Intelligent Systems is the first self- contained volume that covers this newly established concept in its entirety, from a systematic methodology to case studies to industrial applications. Featuring chapters written by leading world experts, it addresses the progress, trends, and major achievements in this emerging research field, with a strong emphasis on th

  5. Multiple random walks on complex networks: A harmonic law predicts search time

    Science.gov (United States)

    Weng, Tongfeng; Zhang, Jie; Small, Michael; Hui, Pan

    2017-05-01

    We investigate multiple random walks traversing independently and concurrently on complex networks and introduce the concept of mean first parallel passage time (MFPPT) to quantify their search efficiency. The mean first parallel passage time represents the expected time required to find a given target by one or some of the multiple walkers. We develop a general theory that allows us to calculate the MFPPT analytically. Interestingly, we find that the global MFPPT follows a harmonic law with respect to the global mean first passage times of the associated walkers. Remarkably, when the properties of multiple walkers are identical, the global MFPPT decays in a power law manner with an exponent of unity, irrespective of network structure. These findings are confirmed by numerical and theoretical results on various synthetic and real networks. The harmonic law reveals a universal principle governing multiple random walks on networks that uncovers the contribution and role of the combined walkers in a target search. Our paradigm is also applicable to a broad range of random search processes.

  6. Cenozoic evolution of the central Walker Lane Belt, west-central Nevada

    Science.gov (United States)

    Petronis, Michael S.

    This dissertation is a collection of four papers that investigate deformation along the North America/Pacific plate boundary, geomagnetic field behavior, and aspects of volcanism in the western part of the Basin and Range Province. Active deformation along the America/Pacific plate boundary is distributed eastward across a wide zone of the western margin of the North American plate, from the San Andreas Fault eastward into the western Basin and Range province an area referred to as the Walker Lane Belt. Chapter three and four investigate aspects of deformation that has been transferred inboard of the continental plate boundary since the mid-Cenozoic inception of the system by investigating a key areas of the central Walker Lane Belt, west-central Nevada (Mina Deflection and southwest Silver Peak Range), where a significant component of the residual strain is being distributed. Deformation in these two areas is being accommodated along a system of late Cenozoic faults with strain partitioned into components of extension, strike slip faulting, and rotation of crustal blocks between the fault systems in the region. The results of this study allow for an assessment of late Tertiary deformation, which leads to a better understanding of the kinematics of deformation in this important part of the Walker Lane Belt. Chapter two investigates the transport direction of the Candelaria pyroclastic sequence by the anisotropy of magnetic susceptibility (AMS) technique. The AMS data are spatially variable across the region and indicate variable transport directions of the three regionally extensive ignimbrite deposits. The AMS fabric data indicate that the Candelaria pyroclastic sequence was erupted from distinct source areas likely separated by several kilometers. Chapter one investigates unusual geomagnetic field behavior at 25.7 Ma and 23.8 Ma preserved in volcanic rocks in the Mina Deflection. Paleomagnetic data indicate that parts of two transitional field records or reversal

  7. Pore size distribution and methane equilibrium conditions at Walker Ridge Block 313, northern Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Bihani, Abhishek [University of Texas at Austin; Daigle, Hugh [University of Texas at Austin; Cook, Ann [Ohio State University; Glosser, Deborah [Ohio State University; Shushtarian, Arash [University of Texas at Austin

    2015-12-15

    Coexistence of three methane phases (liquid (L), gas (G), hydrate (H)) in marine gas hydrate systems may occur according to in-situ pressure, temperature, salinity and pore size. In sediments with salinity close to seawater, a discrete zone of three-phase (3P) equilibrium may occur near the base of the regional hydrate stability zone (RHSZ) due to capillary effects. The existence of a 3P zone influences the location of the bottom-simulating reflection (BSR) and has implications for methane fluxes at the base of the RHSZ. We studied hydrate stability conditions in two wells, WR313-G and WR313-H, at Walker Ridge Block 313 in the northern Gulf of Mexico. We determined pore size distributions (PSD) by constructing a synthetic nuclear magnetic resonance (NMR) relaxation time distribution. Correlations were obtained by non-linear regression on NMR, gamma ray, and bulk density logs from well KC-151 at Keathley Canyon. The correlations enabled construction of relaxation time distributions for WR313-G and WR313-H, which were used to predict PSD through comparison with mercury injection capillary pressure measurements. With the computed PSD, L+H and L+G methane solubility was determined from in-situ pressure and temperature. The intersection of the L+G and L+H curves for various pore sizes allowed calculation of the depth range of the 3P equilibrium zone. As in previous studies at Blake Ridge and Hydrate Ridge, the top of the 3P zone moves upwards with increasing water depth and overlies the bulk 3P equilibrium depth. In clays at Walker Ridge, the predicted thickness of the 3P zone is approximately 35 m, but in coarse sands it is only a few meters due to the difference in absolute pore sizes and the width of the PSD. The thick 3P zone in the clays may explain in part why the BSR is only observed in the sand layers at Walker Ridge, although other factors may influence the presence or absence of a BSR.

  8. Pore Size Distribution and Methane Equilibrium Conditions at Walker Ridge Block 313, Northern Gulf of Mexico

    Science.gov (United States)

    Bihani, A. D.; Daigle, H.; Cook, A.; Glosser, D.; Shushtarian, A.

    2015-12-01

    Coexistence of three methane phases (liquid (L), gas (G), hydrate (H)) in marine gas hydrate systems may occur according to in-situ pressure, temperature, salinity and pore size. In sediments with salinity close to seawater, a discrete zone of three-phase (3P) equilibrium may occur near the base of the regional hydrate stability zone (RHSZ) due to capillary effects. The existence of a 3P zone influences the location of the bottom-simulating reflection (BSR) and has implications for methane fluxes at the base of the RHSZ. We studied hydrate stability conditions in two wells, WR313-G and WR313-H, at Walker Ridge Block 313 in the northern Gulf of Mexico. We determined pore size distributions (PSD) by constructing a synthetic nuclear magnetic resonance (NMR) relaxation time distribution. Correlations were obtained by non-linear regression on NMR, gamma ray, and bulk density logs from well KC-151 at Keathley Canyon. The correlations enabled construction of relaxation time distributions for WR313-G and WR313-H, which were used to predict PSD through comparison with mercury injection capillary pressure measurements. With the computed PSD, L+H and L+G methane solubility was determined from in-situ pressure and temperature. The intersection of the L+G and L+H curves for various pore sizes allowed calculation of the depth range of the 3P equilibrium zone. As in previous studies at Blake Ridge and Hydrate Ridge, the top of the 3P zone moves upwards with increasing water depth and overlies the bulk 3P equilibrium depth. In clays at Walker Ridge, the predicted thickness of the 3P zone is approximately 35 m, but in coarse sands it is only a few meters due to the difference in absolute pore sizes and the width of the PSD. The thick 3P zone in the clays may explain in part why the BSR is only observed in the sand layers at Walker Ridge, although other factors may influence the presence or absence of a BSR.

  9. Preface: evolving rotifers, evolving science: Proceedings of the XIV International Rotifer Symposium

    Czech Academy of Sciences Publication Activity Database

    Devetter, Miloslav; Fontaneto, D.; Jersabek, Ch.D.; Welch, D.B.M.; May, L.; Walsh, E.J.

    2017-01-01

    Roč. 796, č. 1 (2017), s. 1-6 ISSN 0018-8158 Institutional support: RVO:60077344 Keywords : evolving rotifers * 14th International Rotifer Symposium * evolving science Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 2.056, year: 2016

  10. Review of the East Palaearctic and North Oriental Psyttalia Walker, with the description of three new species (Hymenoptera, Braconidae, Opiinae)

    NARCIS (Netherlands)

    Wu, Q.; Achterberg, van C.; Tan, J.-L.; Chen, X.-X.

    2016-01-01

    The East Palaearctic and North Oriental species of the genus Psyttalia Walker (Hymenoptera, Braconidae, Opiinae) are reviewed. Three new species are described and illustrated: P. latinervis Wu & van Achterberg, sp. n. and P. majocellata Wu & van Achterberg, sp. n. from China, and P. spectabilis van

  11. Description of a new species and subspecies of Idalus Walker from Costa Rica, Honduras and Guatemala (Lepidoptera, Erebidae, Arctiinae, Arctiini)

    Science.gov (United States)

    Espinoza, Bernardo A.; Janzen, Daniel H.; Winnie Hallwachs;  J. Bolling Sullivan

    2013-01-01

    Abstract A new species and subspecies of Idalus Walker are described from Costa Rica, Honduras and Guatemala. Images of males and females and their genitalia are provided. Locality information and distribution maps for Costa Rica and for Guatemala are included. The biology and phylogeny of Idalus are discussed. PMID:23730178

  12. Kinetic equations for ultrarelativistic particles in a Robertson-Walker Universe and isotropization of relict radiation by gravitational interactions

    CERN Document Server

    Ignatyev, Yu G

    2011-01-01

    Kinetic equations for ultrarelativistic particles with due account of gravitational interactions with massive particles in the Robertson-Walker universe are obtained. On the basis of an exact solution of the kinetic equations thus obtained, a conclusion is made as to the high degree of the uniformity of the relict radiation on scales with are less than $10'$.

  13. Case 3724 - Metochus abbreviatus Scott, 1874 (Insecta, Heteroptera): proposed precedence over Rhyparochromus erosus Walker, 1872 (currently Metochus erosus)

    Science.gov (United States)

    The purpose of this application, under Article 23.9.3 of the Code, is to conserve the widely used specific name Metochus abbreviatus Scott, 1874, for a species of rhyparochromid bugs from East Asia. The name is threatened by the senior subjective synonym Metochus erosus (Walker, 1872), which has bee...

  14. Rapid Communication. Tamarixia monesus (Walker (Hym.: Eulophidae parasitoid of Bactericera tremblayi (Wagner, 1961 (Hemiptera: Triozidae in Iran

    Directory of Open Access Journals (Sweden)

    Lotfalizadeh Hossein

    2016-08-01

    Full Text Available Bactericera tremblayi (Wagner, 1961 (Hemiptera: Triozidae is reported on Brassica oleracea var. capitata (Brassicaceae in northwestern Iran. Tamarixia monesus (Walker (Hymenoptera: Chalcidoidea, Eulophidae was reared for the first time on B. tremblayi, and compared with Tamarixia tremblayi, another parasitoid of B. tremblayi. This is a new record of T. monesus from the Middle East.

  15. Low carbohydrate, high fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers.

    Science.gov (United States)

    Burke, Louise M; Ross, Megan L; Garvican-Lewis, Laura A; Welvaert, Marijke; Heikura, Ida A; Forbes, Sara G; Mirtschin, Joanne G; Cato, Louise E; Strobel, Nicki; Sharma, Avish P; Hawley, John A

    2017-05-01

    Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support. Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole-body fat oxidation during exercise in race walkers over a range of exercise intensities. The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real-life race performance in elite race walkers. In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity. We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world-class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg -1  day -1 : 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (economy. © 2016 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

  16. Changes in Energy Cost and Total External Work of Muscles in Elite Race Walkers Walking at Different Speeds

    Directory of Open Access Journals (Sweden)

    Chwała Wiesław

    2014-12-01

    Full Text Available The aim of the study was to assess energy cost and total external work (total energy depending on the speed of race walking. Another objective was to determine the contribution of external work to total energy cost of walking at technical, threshold and racing speed in elite competitive race walkers.

  17. Dandy-walker malformation and the contribution of radioisotopic studies of cerebral spinal fluid dynamics to its diagnosis. Case report

    Energy Technology Data Exchange (ETDEWEB)

    Palma, A.; Nazar, N.; Castro, M.; Olea, E.; Guzmann, G. (Inst. of Neurosurgery, Santiago (Chile))

    1982-01-01

    One case of Dandy-Walker malformation is described. The diagnosis was mainly reached by dynamic isotope studies of CSF, and was confirmed by axial computerized tomography. The importance of these examinations is discussed, not only as a means of understanding the aetiopathology, but especially because of the functional information they give and the therapeutic consequences they have.

  18. Neuropsychological and Behavioural Phenotype of Dandy-Walker Variant Presenting in Chromosome 22 Trisomy: A Case Study

    Science.gov (United States)

    Searson, Ruth; Hare, Dougal Julian; Sridharan, Sridhar

    2013-01-01

    In this study, a case of Dandy-Walker variant syndrome associated with trisomy 22 in a 17-year-old man is described. This is the first account of this combination in a person surviving into adulthood, and the neuropsychological and behavioural presentation is described in detail and a clinical formulation is presented for the benefit of…

  19. Life table studies of rachiplusia nu (guenée) and chrysodeixis (= pseudoplusia) includens (Walker) (lepidoptera: noctuidae) on artificial diet

    Science.gov (United States)

    Rachiplusia nu (Guenée) and Chrysodeixis (= Pseudoplusia) includens (Walker) (Lepidoptera: Noctuidae) are two economically important species in soybean in northern Argentina. Life cycle, reproductive and population parameters of R. nu and C. includens reared on artificial diet were determined under ...

  20. Random walks along the streets and canals in compact cities: Spectral analysis, dynamical modularity, information, and statistical mechanics

    Science.gov (United States)

    Volchenkov, D.; Blanchard, Ph.

    2007-02-01

    Different models of random walks on the dual graphs of compact urban structures are considered. Analysis of access times between streets helps to detect the city modularity. The statistical mechanics approach to the ensembles of lazy random walkers is developed. The complexity of city modularity can be measured by an informationlike parameter which plays the role of an individual fingerprint of Genius loci. Global structural properties of a city can be characterized by the thermodynamic parameters calculated in the random walk problem.

  1. Thermal and Evolved-Gas Analyzer Illustration

    Science.gov (United States)

    2008-01-01

    This is a computer-aided drawing of the Thermal and Evolved-Gas Analyzer, or TEGA, on NASA's Phoenix Mars Lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  2. Apollo 16 Evolved Lithology Sodic Ferrogabbro

    Science.gov (United States)

    Zeigler, Ryan; Jolliff, B. L.; Korotev, R. L.

    2014-01-01

    Evolved lunar igneous lithologies, often referred to as the alkali suite, are a minor but important component of the lunar crust. These evolved samples are incompatible-element rich samples, and are, not surprisingly, most common in the Apollo sites in (or near) the incompatible-element rich region of the Moon known as the Procellarum KREEP Terrane (PKT). The most commonly occurring lithologies are granites (A12, A14, A15, A17), monzogabbro (A14, A15), alkali anorthosites (A12, A14), and KREEP basalts (A15, A17). The Feldspathic Highlands Terrane is not entirely devoid of evolved lithologies, and rare clasts of alkali gabbronorite and sodic ferrogabbro (SFG) have been identified in Apollo 16 station 11 breccias 67915 and 67016. Curiously, nearly all pristine evolved lithologies have been found as small clasts or soil particles, exceptions being KREEP basalts 15382/6 and granitic sample 12013 (which is itself a breccia). Here we reexamine the petrography and geochemistry of two SFG-like particles found in a survey of Apollo 16 2-4 mm particles from the Cayley Plains 62283,7-15 and 62243,10-3 (hereafter 7-15 and 10-3 respectively). We will compare these to previously reported SFG samples, including recent analyses on the type specimen of SFG from lunar breccia 67915.

  3. Effect of Diapause Ondevelopment and Reproduction of White Rice Stem Borer Scirpophaga innotata Walker (Lepidoptera: Pyralidae

    Directory of Open Access Journals (Sweden)

    Teddy Suparno

    1998-12-01

    Full Text Available The objective of this study was to determine the effect of diapause on the development and reproduction of white rice stem borer (WRSB, Scirpophaga innotata Walker. During diapause, larvae of the WRSB, progressively decreased in weight at the rate 3.2 mg per week. Larvae lost 50 per cent of their initial body mass and had up to four stationary molts. Larvae became less active, lost pigmentation and leg rudimentary. The longer the larvae remained in diapause, the lighter in weight the emerging moths were, with fewer eggs and oocytes. After 5 months in diapause, the emerging moths weighted about half as much and had about half as many eggs and oocytes (230.0±35.8 egg cells in ovaries as moths that emerged from nondiapausing larvae. Key words: insecta, white rice stem rice borer, Scirpophaga innotata, diapause

  4. ENSO impacts on the South American rainfall during 1980s: Hadley and Walker circulation

    Energy Technology Data Exchange (ETDEWEB)

    De Souza, E.B.; Ambrizzi, T. [Departamento de Ciencias Atmosfericas, Instituto Astronomico y Geofisico, Sao Paulo, SP (Brazil)

    2002-04-01

    The changes in the Hadley and Walter cells and their respective impacts on the South American rainfall during the ENSO episodes observed in the decade of 80, were investigated through cross-sections analyses of the atmospheric circulation in altitude, averaged in the zonal and meridional planes. Such large-scale cells almost inverted their climatological circulation pattern, during El Nino events (1982-83 and 1986-87). In these years, manifestation of the anomalous descending branch of the Hadley and Walker cells affects most of the north-northeast of South America, which inhibited the convective activity associated to the Inter Tropical Convergence Zone (ITCZ) and caused drought conditions in the rainy seasons of the Guyana, Surinam, French Guyana, center-east of the Amazon and most of the Northeast Brazil. On the other hand, conditions of excess of precipitation observed in the south-southeast of South America, were favored by the anomalous ascending branch of the Hadley cell. During La Nina events (1984-85 and 1988-89), it was observed an intensification of the ascending and descending branches associated to the Walker and Hadley cells. The anomalous large-scale ascending movement associated to these cells, was extended to the Northeast of Brazil and equatorial South Atlantic, favoring ITCZ to become more active than the normal, which resulted in an above normal rainy season in these areas. An intense subsidence was noticed in the mid latitudes of South America, which inhibited the large-scale convection in the region, explaining the deficient rainy season observed in most of the south-southeast of South America. [Spanish] Los cambios en las celulas de Hadley y Walker y sus respectivos impactos en Suramerica, en las lluvias, durante los episodios en ENOS, observados en la decada de los 80, son investigados a traves de analisis de reacciones cruzadas de la circulacion atmosferica en altitudes promediadas en planos zonal y meridional. Tales celulas de gran escala

  5. Seasonal nutrient dynamics of foliage and litterfall on Walker Branch Watershed, a deciduous forest ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Grizzard, T.; Henderson, G.S.; Clebsch, E.E.C.; Reichle, D.E.

    1976-03-01

    A detailed twelve-month study of litterfall, live foliage biomass, and seasonal nutrient (nitrogen, phosphorus, potassium, calcium, sodium, and magnesium) dynamics in tree components was performed for forest types on Walker Branch Watershed, Oak Ridge, Tennessee. Biomass and nutrient content of foliage, reproductive parts and branches were examined for ten dominant trees in order to assess the relative importance of litterfall in returning nutrients to the forest floor in four different forest types. Litterfall, measured in pine, pine-oak-hickory, oak-hickory, and mesophytic hardwood forests, was separated into three components (leaves, reproductive parts, and branches). Seasonal comparisons of those forest types were made for biomass and nutrient inputs for each component and for total litterfall.

  6. Walker Branch Throughfall Displacement Experiment Data Report: Site Characterization, System Performance, Weather, Species Composition, and Growth

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, P.J.

    2001-09-04

    This numeric data package provides data sets, and accompanying documentation, on site characterization, system performance, weather, species composition, and growth for the Throughfall Displacement Experiment, which was established in the Walker Branch Watershed of East Tennessee to provide data on the responses of forests to altered precipitation regimes. The specific data sets include soil water content and potential, coarse fraction of the soil profile, litter layer temperature, soil temperature, monthly weather, daily weather, hourly weather, species composition of trees and saplings, mature tree and sapling annual growth, and relative leaf area index. Fortran and SAS{trademark} access codes are provided to read the ASCII data files. The data files and this documentation are available without charge on a variety of media and via the Internet from the Carbon Dioxide Information Analysis Center (CDIAC).

  7. "It feels good to be measured": clinical role-play, Walker Percy, and the tingles.

    Science.gov (United States)

    Ahuja, Nitin K

    2013-01-01

    A large online community has recently formed around autonomous sensory meridian response (ASMR), a pleasant and poorly understood somatic reaction to specific interpersonal triggers. Its web-based manifestations include a variety of amateur videos designed to elicit the reaction, many of which feature protracted imitations of a clinician's physical exam. This analysis considers through a literary lens the proximity of this phenomenon to clinical diagnostics, focusing in particular on characterizations of spiritual isolation elaborated in Love in the Ruins (1971), the third novel by physician-writer Walker Percy (1916-1990). Within this speculative framework, the tendency to derive pleasure from clinical milieus, real or constructed, may be interpreted as a quality particular to the postmodern psyche. Viewing web-based clinical role-play in light of Percy's writing also underscores the possibility that routine diagnostic assessments may have independent therapeutic implications.

  8. Effects of field interactions upon particle creation in Robertson-Walker universes

    Science.gov (United States)

    Birrell, N. D.; Davies, P. C. W.; Ford, L. H.

    1980-01-01

    Particle creation due to field interactions in an expanding Robertson-Walker universe is investigated. A model in which pseudoscalar mesons and photons are created as a result of their mutual interaction is considered, and the energy density of created particles is calculated in model universes which undergo a bounce at some maximum curvature. The free-field creation of non-conformally coupled scalar particles and of gravitons is calculated in the same space-times. It is found that if the bounce occurs at a sufficiently early time the interacting particle creation will dominate. This result may be traced to the fact that the model interaction chosen introduces a length scale which is much larger than the Planck length.

  9. Dynamic pedobarographic classification of idiopathic toe-walkers for therapeutical indication

    Directory of Open Access Journals (Sweden)

    Patricia Martín-Casas

    2017-03-01

    Full Text Available Idiopathic toe-walkers (ITWs pedobarographic analysis has not been described yet nor its possible relationship with orthopedical and developmental characteristics. The objective of this research is to develop a dynamic pedobarographic classification of ITWs to propose a specific therapeutical approach. Through an observational study, 56 ITWs aged 3-6 years were classified by their initial foot contact; differences between idiopatic toe-walking (ITW types and with respect to 40 control children were calculated by means of ANOVA and Student t-tests. The results show that the three ITW types displayed different step models for pressure and impulse distribution and also for temporal development (p less than .05. They also showed different orthopedic and developmental characteristics (p less than .05. As a whole, they demonstrated different severity levels, which suggest different therapeutical indications. This study confirms the convenience of a specific orthopedic, developmental, and gait assessment in ITW to clarify therapeutical indication.

  10. NMR images of non-communicating hydrocephalus associated with Dandy-Walker variant and achondroplasia

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Masaharu; Kuroda, Ryotaro; Watanabe, Masaru; Nakatani, Jiro; Ioku, Masahiko; Irisawa, Minoru; Hamada, Tatsumi; Ishida, Osamu

    1988-06-01

    Two cases of non-communicating hydrocephalus caused by a relatively rare etiology were reported. They were both diagnosed by means of nuclear magnetic resonance (NMR). The first patient, a 4-month-old boy, had Dandy-Walker variant, showing hypoplasia of the corpus callosum and the inferior vermis, and a large cyst behind the vermis, communicating with the subarachnoid space, as well as hydrocephalus; the fourth ventricle was partially reserved. The second patient, also a 4-month-old boy, had achondroplasia, resulting in a narrow foramen magnum; the disturbance of the outflow of the cerebro-spinal fluid around the cisterna magna was thought to be the cause of hydrocephalus in his case. The validity of NMR was demonstrated in the diagnoses of these conditions, for a high resolution was needed in examining the complicated structure of the posterior fossa.

  11. Intellectual prognosis of the Dandy-Walker malformation in children: the importance of vermian lobulation

    Energy Technology Data Exchange (ETDEWEB)

    Boddaert, N.; Brunelle, F. [Paediatric Radiology Department, Hopital Necker Enfants-Malades, 149 rue de Sevres, 75015, Paris (France); ERM 0205 INSERM-CEA, Service Hospitalier Frederic Joliot, CEA, Orsay (France); Klein, O.; Parisot, D.; Pierre-Kahn, A. [Neurosurgical Department, Hopital Necker Enfants-Malades, 149 rue de Sevres, 75015, Paris (France); Ferguson, N.; Sonigo, P.; Hertz-Pannier, L.; Baraton, J.; Emond, S.; Simon, I.; Chigot, V.; Schmit, P. [Paediatric Radiology Department, Hopital Necker Enfants-Malades, 149 rue de Sevres, 75015, Paris (France)

    2003-05-01

    Half of patients with the Dandy-Walker malformation (DWM) have normal intellectual development. We aimed to identify feature on MRI associated with good intellectual prognosis. We reviewed 20 patients with DWM diagnosed on MRI, mean age 14.6{+-}9.9 years. We assessed their intellectual development and related it to the MRI features. We found two groups with a statistically different intellectual outcome. All 14 patients with normal intellectual development had a normal lobulation of the vermis, without supratentorial anomalies. Of the six patients with mental retardation, three had an abnormal vermis, together with dysgenesis of the corpus callosum. In the other three, there were normal vermian anatomy with associated anomalies. Normal lobulation of the vermis, in the absence of any supratentorial anomaly, appears to be a good prognostic factor in DWM. Preservation of cerebrocerebellar pathways and neonatal plasticity could explain the normal intellectual development. These findings might be useful in prenatal diagnosis. (orig.)

  12. Dandy-Walker malformation, genitourinary abnormalities, and intellectual disability in two families.

    Science.gov (United States)

    Zaki, Maha S; Masri, Amira; Gregor, Anne; Gleeson, Joseph G; Rosti, Rasim Ozgur

    2015-11-01

    We report on two families, each with documented consanguinity and two affected with overlapping features of Dandy-Walker malformation, genitourinary abnormalities, intellectual disability, and hearing deficit. This phenotype shares similar findings with many well-known syndromes. However, the clinical findings of this syndrome categorize this as a new syndrome as compared with the phenotype of already established syndromes. Due to parental consanguinity, occurrence in siblings of both genders and the absence of manifestations in obligate carrier parents, an autosomal recessive pattern of inheritance is more likely. The authors believe that these families suggest a novel autosomal recessive cerebello-genital syndrome. Array CGH analyses of an affected did not show pathological deletions or duplications. © 2015 Wiley Periodicals, Inc.

  13. Dandy-Walker malformation and neurocutaneous melanosis in a three-month-old infant

    Science.gov (United States)

    Mahgoub, Shaza Mohamed; Yassin, Rehab Omer; Osman, Atika Mohamed

    2013-01-01

    Dandy-Walker Malformation (DWM) is a rare congenital malformation of the brain. It is characterized by cystic enlargement of the fourth ventricle which is communicating with an enlarged posterior fossa, cerebellar dysgenesis, high tentorial insertion and hydrocephalus. Neurocutaneous Melanosis (NCM) is a congenital neurocutaneous syndrome characterized by large or multiple melanocytic nevi and benign or malignant melanocytic tumors of the leptomeninges. We report three months old boy who presented with projectile vomiting associated with a noticeable increase in head size. Several congenital nevi were seen all over his body with evident signs of hydrocephalus. The association of DWM and NCM is a rare complex, and to our knowledge, this is the eleventh case to be reported in the literature. In this article, we discuss the proposed pathogenesis, classification and management of the condition. PMID:27493376

  14. First-trimester sonographic findings associated with a Dandy-Walker malformation and inferior vermian hypoplasia.

    Science.gov (United States)

    Bornstein, Eran; Goncalves Rodríguez, José Luis; Álvarez Pavón, Erika Carolina; Quiroga, Héctor; Or, Drorit; Divon, Michael Y

    2013-10-01

    We report 2 cases in which first-trimester measurements of the intracranial translucency and the brain stem-to-occipital bone diameter were markedly enlarged. This finding was thought to represent an abnormal fourth ventricle-cisterna magna complex. Subsequently, the diagnoses of a Dandy-Walker malformation with partial vermian agenesis in 1 case and inferior vermian hypoplasia in the other were established and confirmed by either postmortem autopsy or postnatal magnetic resonance imaging. These cases suggest that evaluation of the fourth ventricle-cisterna magna complex, by measuring the intracranial translucency or brain stem-to-occipital bone diameter may identify some cases with structural malformations of the cerebellum as early as the first trimester.

  15. Neurocutaneous melanosis in association with dandy-walker complex with extensive intracerebral and spinal cord involvement.

    Science.gov (United States)

    Sung, Kyoung-Su; Song, Young-Jin

    2014-07-01

    Neurocutaneous melanosis (NCM) is a rare congenital syndrome consisting of benign or malignant melanotic tumors of the central nervous system with large or numerous cutaneous melanocytic nevi. The Dandy-Walker complex (DWC) is characterized by an enlarged posterior fossa with high insertion of the tentorium, hypoplasia or aplasia of the cerebellar vermis, and cystic dilatation of the fourth ventricle. These each two conditions are rare, but NCM associated with DWC is even more rare. Most patients of NCM with DWC present neurological symptoms early in life such as intracranial hemorrhage, hydrocephalus, and malignant transformation of the melanocytes. We report a 14-year-old male patient who was finally diagnosed as NCM in association with DWC with extensive intracerebral and spinal cord involvement.

  16. Oral findings and dental treatment in a patient with Dandy-Walker syndrome: a case report.

    Science.gov (United States)

    Kusumoto, Yasuka; Shinozuka, Osamu

    2014-01-01

    Dandy-Walker syndrome (DWS) is congenital disease characterized by hypoplasia of the cerebellum, the formation of cysts that communicate with the fourth ventricle of the posterior cranial fossa, and hydrocephalus. In addition to various other complications, cleft lip/palate, facial retrognathia, a high-arched palate, and maldentition occur at an increased frequency in patients with DWS. However, few studies have reported the dental manifestations of DWS. Herein, we report the clinical manifestations, oral findings, and dental management of a DWS patient who was treated under general anesthesia. Poor oral hygiene, gingivitis, and several congenital dental abnormalities (e.g., generalized microdontia, conical tooth, transposition, and congenitally missing teeth) were observed. This report is the first to describe the oral findings and dental treatment of DWS. Our findings emphasize the importance of a multidisciplinary approach in the diagnosis and treatment of DWS. © 2013 Special Care Dentistry Association and Wiley Periodicals, Inc.

  17. Oral-facial-digital syndrome type 1 with hypothalamic hamartoma and Dandy-Walker malformation.

    Science.gov (United States)

    Azukizawa, Takayuki; Yamamoto, Masahito; Narumiya, Seirou; Takano, Tomoyuki

    2013-04-01

    We report a 1-year-old girl with oral-facial-digital syndrome type 1 with multiple malformations of the oral cavity, face, digits, and central nervous system, including agenesis of the corpus callosum, the presence of intracerebral cysts, and agenesis of the cerebellar vermis, which is associated with the subarachnoid space separating the medial sides of the cerebellar hemispheres. This child also had a hypothalamic hamartoma and a Dandy-Walker malformation, which have not been reported previously. The clinical features, including cerebral malformations, in several types of oral-facial-digital syndrome, overlap with each other. Further accumulation of new case reports and identification of new genetic mutations in oral-facial-digital syndrome may provide novel and important insights into the genetic mechanisms of this syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. [Performance of trichogrammatids as biocontrol agents of Pseudoplusia includens Walker (Lepidoptera: Noctuidae)].

    Science.gov (United States)

    Bueno, Regiane C O F; Parra, José R P; de F Bueno, Adeney; Haddad, Marinéia L

    2009-01-01

    This research aimed to point out the most suitable trichogrammatid strains to control the soybean looper Pseudoplusia includes Walker. Biological parameters and parasitism ratio of 11 Trichogramma pretiosum Riley, one Trichogramma atopovirilia Oatman & Platner and one Trichogrammatoidea annulata De Santis strains reared on P. includens eggs were evaluated. Among all tested strains/species, T. pretiosum strain RV, collected in Rio Verde, GO, had the fastest development cycle and the highest percentage of parasitism of P. includens eggs. There was no difference in the parasitism and in the number of parasitoid emerged per egg among the tested parasitoid species and strains. Accordingly to the cluster analysis, T. pretiosum strain RV reared on P. includens eggs had the best performance. Considering the higher parasitism rate, shorter biological cycle, higher survival and sex ratio, T. pretiosum strain RV is the most appropriated to be used in field releases aiming at P. includens control.

  19. A Kinematic Model for Vertical Axis Rotation within the Mina Deflection of the Walker Lane

    Science.gov (United States)

    Gledhill, T.; Pluhar, C. J.; Johnson, S. A.; Lindeman, J. R.; Petronis, M. S.

    2016-12-01

    The Mina Deflection, at the boundary between the Central and Southern Walker Lane, spans the California-Nevada border and includes a heavily-faulted Pliocene volcanic field overlying Miocene ignimbrites. The dextral Walker Lane accommodates 25% of relative Pacific-North America plate motion and steps right across the sinistral Mina deflection. Ours and previous work shows that the Mina Deflection partially accommodates deformation by vertical-axis rotation of up to 99.9o ± 6.1o rotation since 11 Ma. This rotation is evident in latite ignimbrite of Gilbert et al. (1971), which we have formalized as three members of Tuff of Huntoon Creek (THC). The welded, basal, normal-polarity Huntoon Valley Member of THC is overlain by the unwelded to partially-welded, reversed-polarity Adobe Hills Mbr. This member includes internal breaks suggesting multiple eruptive phases, but the paleomagnetic results from each are statistically indistinguishable, meaning that they were likely erupted in rapid succession (within a few centuries of one another). THC ends with a welded member exhibiting very shallow inclination and south declination that we call Excursional Mbr. One of the upper members has been dated at 11.17 ± 0.04 Ma. These Miocene units are overlain by Pliocene basalts, Quaternary alluvium, and lacustrine deposits. Our paleomagnetic results show a gradient between the zero rotation domain and high rotation across a 20km baseline. A micropolar model, based on 25 years of earthquake data from the Northern and Southern California Seismic Network, suggest the Mina Deflection is currently experiencing transpressional seismogenic deformation (Unruh et al., 2003). Accepting Unruh's model and assuming continuous rotation since 11 Ma, we propose a kinematic model for the western Mina Deflection that accommodates 90o of vertical axis rotation from N-S to ENE-WSW oriented blocks.

  20. “Ancestors We Didn’t Even Know We Had”: Alice Walker, Asian Religion, and Ethnic Authenticity

    Directory of Open Access Journals (Sweden)

    Kyle Garton-Gundling

    2015-03-01

    Full Text Available Recent debates about the ethics of identity in a global age have dealt with how to prioritize conflicting local and global allegiances. Guided by these concerns, the fiction of Alice Walker develops a distinctive view of how local cultures and global movements can fruitfully interact. This vision depends on concepts from Asian religions, a major influence that critics of Walker have largely overlooked. Walker promotes Hindu and Buddhist meditation in a context of widespread African American skepticism toward Asian religions. According to widespread notions of cultural authenticity, Asian religions cannot nourish an African American connection to ethnic roots. In response to this challenge, Alice Walker’s fiction portrays Hindu and Buddhist mystics as African Americans’ ancestors, thus positioning these faiths as authentically black. By creatively enfolding Asian religions into her sense of African American heritage, Walker builds a spiritual cosmopolitanism that relies on claims of ancestral affiliation even when these claims are not literal. This strategy is Walker’s effort to create a new paradigm of cultural authenticity, one that allows individuals and groups to choose their ancestors. Walker’s approach seeks to incorporate disparate global influences while still valorizing the figure of the ancestor. This innovative approach places Walker at the forefront of a growing number of African American artists and intellectuals who promote Asian religions to American minorities. Walker’s work vividly dramatizes larger concerns in transnational American Studies: Eastern philosophy’s relevance to identity politics, the tensions between universal ideals and cultural specifics, and the ethics of cross-cultural appropriation.

  1. Evolving networks-Using past structure to predict the future

    Science.gov (United States)

    Shang, Ke-ke; Yan, Wei-sheng; Small, Michael

    2016-08-01

    Many previous studies on link prediction have focused on using common neighbors to predict the existence of links between pairs of nodes. More broadly, research into the structural properties of evolving temporal networks and temporal link prediction methods have recently attracted increasing attention. In this study, for the first time, we examine the use of links between a pair of nodes to predict their common neighbors and analyze the relationship between the weight and the structure in static networks, evolving networks, and in the corresponding randomized networks. We propose both new unweighted and weighted prediction methods and use six kinds of real networks to test our algorithms. In unweighted networks, we find that if a pair of nodes connect to each other in the current network, they will have a higher probability to connect common nodes both in the current and the future networks-and the probability will decrease with the increase of the number of neighbors. Furthermore, we find that the original networks have their particular structure and statistical characteristics which benefit link prediction. In weighted networks, the prediction algorithm performance of networks which are dominated by human factors decrease with the decrease of weight and are in general better in static networks. Furthermore, we find that geographical position and link weight both have significant influence on the transport network. Moreover, the evolving financial network has the lowest predictability. In addition, we find that the structure of non-social networks has more robustness than social networks. The structure of engineering networks has both best predictability and also robustness.

  2. The Role of Walkers’ Needs and Expectations in Supporting Maintenance of Attendance at Walking Groups: A Longitudinal Multi-Perspective Study of Walkers and Walk Group Leaders

    Science.gov (United States)

    Kassavou, Aikaterini; Turner, Andrew; French, David P.

    2015-01-01

    Background There is good evidence that when people’s needs and expectations regarding behaviour change are met, they are satisfied with that change, and maintain those changes. Despite this, there is a dearth of research on needs and expectations of walkers when initially attending walking groups and whether and how these needs and expectations have been satisfied after a period of attendance. Equally, there is an absence of research on how people who lead these groups understand walkers’ needs and walk leaders’ actions to address them. The present study was aimed at addressing both of these gaps in the research. Methods Two preliminary thematic analyses were conducted on face-to-face interviews with (a) eight walkers when they joined walking groups, five of whom were interviewed three months later, and (b) eight walk leaders. A multi-perspective analysis building upon these preliminary analyses identified similarities and differences within the themes that emerged from the interviews with walkers and walk leaders. Results Walkers indicated that their main needs and expectations when joining walking groups were achieving long-term social and health benefits. At the follow up interviews, walkers indicated that satisfaction with meeting similar others within the groups was the main reason for continued attendance. Their main source of dissatisfaction was not feeling integrated in the existing walking groups. Walk leaders often acknowledged the same reasons for walkers joining and maintaining attendance at walking. However, they tended to attribute dissatisfaction and drop out to uncontrollable environmental factors and/or walkers’ personalities. Walk leaders reported a lack of efficacy to effectively address walkers’ needs. Conclusions Interventions to increase retention of walkers should train walk leaders with the skills to help them modify the underlying psychological factors affecting walkers’ maintenance at walking groups. This should result in

  3. Integrating the Human Sciences to Evolve Effective Policies.

    Science.gov (United States)

    Biglan, Anthony; Cody, Christine

    2013-06-01

    This paper describes an evolutionary perspective on human development and wellbeing and contrasts it with the model of self-interest that is prominent in economics. The two approaches have considerably different implications for how human wellbeing might be improved. Research in psychology, prevention science, and neuroscience is converging on an evolutionary account of the importance of two contrasting suites of social behavior-prosociality vs. antisocial behaviors (crime, drug abuse, risky sexual behavior) and related problems such as depression. Prosociality of individuals and groups evolves in environments that minimize toxic biological and social conditions, promote and richly reinforce prosocial behavior and attitudes, limit opportunities for antisocial behavior, and nurture the pursuit of prosocial values. Conversely, antisocial behavior and related problems emerge in environments that are high in threat and conflict. Over the past 30 years, randomized trials have shown numerous family, school, and community interventions to prevent most problem behaviors and promote prosociality. Research has also shown that poverty and economic inequality are major risk factors for the development of problem behaviors. The paper describes policies that can reduce poverty and benefit youth development. Although it is clear that the canonical economic model of rational self-interest has made a significant contribution to the science of economics, the evidence reviewed here shows that it must be reconciled with an evolutionary perspective on human development and wellbeing if society is going to evolve public policies that advance the health and wellbeing of the entire population.

  4. Evolving wormhole geometries within nonlinear electrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Arellano, Aaron V B [Facultad de Ciencias, Universidad Autonoma del Estado de Mexico, El Cerrillo, Piedras Blancas, CP 50200, Toluca (Mexico); Lobo, Francisco S N [Centro de Astronomia e Astrofisica da Universidade de Lisboa, Campo Grande, Ed C8 1749-016 Lisbon (Portugal)

    2006-10-21

    In this work, we explore the possibility of evolving (2 + 1) and (3 + 1)-dimensional wormhole spacetimes, conformally related to the respective static geometries, within the context of nonlinear electrodynamics. For (3 + 1)-dimensional spacetime, it is found that the Einstein field equation imposes a contracting wormhole solution and the obedience of the weak energy condition. Nevertheless, in the presence of an electric field, the latter presents a singularity at the throat; however, for a pure magnetic field the solution is regular. For (2 + 1)-dimensional case, it is also found that the physical fields are singular at the throat. Thus, taking into account the principle of finiteness, which states that a satisfactory theory should avoid physical quantities becoming infinite, one may rule out evolving (3 + 1)-dimensional wormhole solutions, in the presence of an electric field, and (2 + 1)-dimensional case coupled to nonlinear electrodynamics.

  5. Continual Learning through Evolvable Neural Turing Machines

    DEFF Research Database (Denmark)

    Lüders, Benno; Schläger, Mikkel; Risi, Sebastian

    2016-01-01

    Continual learning, i.e. the ability to sequentially learn tasks without catastrophic forgetting of previously learned ones, is an important open challenge in machine learning. In this paper we take a step in this direction by showing that the recently proposed Evolving Neural Turing Machine (ENT......) approach is able to perform one-shot learning in a reinforcement learning task without catastrophic forgetting of previously stored associations.......Continual learning, i.e. the ability to sequentially learn tasks without catastrophic forgetting of previously learned ones, is an important open challenge in machine learning. In this paper we take a step in this direction by showing that the recently proposed Evolving Neural Turing Machine (ENTM...

  6. Designing Garments to Evolve Over Time

    DEFF Research Database (Denmark)

    Riisberg, Vibeke; Grose, Lynda

    2017-01-01

    This paper proposes a REDO of the current fashion paradigm by investigating how garments might be designed to evolve over time. The purpose is to discuss ways of expanding the traditional role of the designer to include temporal dimensions of creating, producing and using clothes and to suggest a...... to a REDO of design education, to further research and the future fashion and textile industry.......This paper proposes a REDO of the current fashion paradigm by investigating how garments might be designed to evolve over time. The purpose is to discuss ways of expanding the traditional role of the designer to include temporal dimensions of creating, producing and using clothes and to suggest...... a range of potential fashion futures that decouple from declining resources. In the first part literature on 'Past and Present' historical and current aspects of sustainability in fashion and textiles are presented. In the second part, three exploratory case studies are described: Two projects by students...

  7. Antibody therapeutics - the evolving patent landscape.

    Science.gov (United States)

    Petering, Jenny; McManamny, Patrick; Honeyman, Jane

    2011-09-01

    The antibody patent landscape has evolved dramatically over the past 30 years, particularly in areas of technology relating to antibody modification to reduce immunogenicity in humans or improve antibody function. In some cases antibody techniques that were developed in the 1980s are still the subject of patent protection in the United States or Canada. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. The evolving epidemiology of inflammatory bowel disease.

    LENUS (Irish Health Repository)

    Shanahan, Fergus

    2009-07-01

    Epidemiologic studies in inflammatory bowel disease (IBD) include assessments of disease burden and evolving patterns of disease presentation. Although it is hoped that sound epidemiologic studies provide aetiological clues, traditional risk factor-based epidemiology has provided limited insights into either Crohn\\'s disease or ulcerative colitis etiopathogenesis. In this update, we will summarize how the changing epidemiology of IBD associated with modernization can be reconciled with current concepts of disease mechanisms and will discuss studies of clinically significant comorbidity in IBD.

  9. Directional Communication in Evolved Multiagent Teams

    Science.gov (United States)

    2013-06-10

    networks. Artificial Life, 15(2):185– 212, 2009. [23] K. O. Stanley and R. Miikkulainen. Evolving neural networks through augmenting topologies ...paper. 2.2 Neuroevolution of Augmenting Topologies The HyperNEAT approach is itself an extension of the original NEAT (Neu- roevolution of Augmenting ...Gauci and K. O. Stanley. Autonomous evolution of topographic regu- larities in artificial neural networks. Neural Computation, 22(7):1860–1898, 2010

  10. The Evolving Leadership Path of Visual Analytics

    Energy Technology Data Exchange (ETDEWEB)

    Kluse, Michael; Peurrung, Anthony J.; Gracio, Deborah K.

    2012-01-02

    This is a requested book chapter for an internationally authored book on visual analytics and related fields, coordianted by a UK university and to be published by Springer in 2012. This chapter is an overview of the leadship strategies that PNNL's Jim Thomas and other stakeholders used to establish visual analytics as a field, and how those strategies may evolve in the future.

  11. Raeder paratrigeminal neuralgia evolving to hemicrania continua.

    Science.gov (United States)

    Porzukowiak, Tina Renae

    2015-04-01

    Raeder paratrigeminal neuralgia is most commonly characterized as deep, boring, nonpulsatile, severe, unilateral facial and head pain in the distribution of the V1 area combined with ipsilateral oculosympathetic palsy and autonomic symptoms. Raeder paratrigeminal neuralgia evolving into hemicrania continua, a rare primary, chronic headache syndrome characterized by unilateral pain and response to indomethacin, has rarely been documented. The purpose of this case report is to contribute to the medical literature a single case of Raeder paratrigeminal neuralgia presenting as multiple cranial nerve palsies that evolved into hemicrania continua that was successfully treated with onabotulinumtoxinA. A 52-year-old white woman presented to the emergency department with the complaint of severe, aching, constant eye pain radiating to the V1 area for 1 week with associated ptosis and photophobia of the left eye. Ocular examination revealed involvement of cranial nerves II, III, V, and VI. Additional symptoms included ipsilateral lacrimation, eyelid edema, and rhinorrhea. Extensive medical work-up showed normal results. Raeder paratrigeminal neuralgia was diagnosed with multiple cranial nerve involvement; the headache component became chronic with periodic exacerbations of autonomic symptoms evolving to a diagnosis of hemicrania continua. The patient was intolerant to traditional indomethacin treatment, and the headache was successfully treated with onabotulinumtoxinA injections. Recognition of ipsilateral signs such as miosis, ptosis, hydrosis, eyelid edema, hyperemia, rhinorrhea, or nasal congestion is useful in the differential diagnosis of painful ophthalmoplegia, particularly in the diagnosis of Raeder paratrigeminal neuralgia and hemicrania continua. This case study illustrates a rare presentation of Raeder paratrigeminal neuralgia evolving into hemicrania continua presenting as a painful ophthalmoplegia with multiple cranial nerve involvement. The example supports the

  12. Evolvability of Amyloidogenic Proteins in Human Brain

    Science.gov (United States)

    Hashimoto, Makoto; Ho, Gilbert; Sugama, Shuei; Takamatsu, Yoshiki; Shimizu, Yuka; Takenouchi, Takato; Waragai, Masaaki; Masliah, Eliezer

    2018-01-01

     Currently, the physiological roles of amyloidogenic proteins (APs) in human brain, such as amyloid-β and α-synuclein, are elusive. Given that many APs arose by gene duplication and have been resistant against the pressures of natural selection, APs may be associated with some functions that are advantageous for survival of offspring. Nonetheless, evolvability is the sole physiological quality of APs that has been characterized in microorganisms such as yeast. Since yeast and human brain may share similar strategies in coping with diverse range of critical environmental stresses, the objective of this paper was to discuss the potential role of evolvability of APs in aging-associated neurodegenerative disorders, including Alzheimer’s disease and Parkinson’s disease. Given the heterogeneity of APs in terms of structure and cytotoxicity, it is argued that APs might be involved in preconditioning against diverse stresses in human brain. It is further speculated that these stress-related APs, most likely protofibrillar forms, might be transmitted to offspring via the germline, conferring preconditioning against forthcoming stresses. Thus, APs might represent a vehicle for the inheritance of the acquired characteristics against environmental stresses. Curiously, such a characteristic of APs is reminiscent of Charles Darwin’s ‘gemmules’, imagined molecules of heritability described in his pangenesis theory. We propose that evolvability might be a physiological function of APs during the reproductive stage and neurodegenerative diseases could be a by-product effect manifested later in aging. Collectively, our evolvability hypothesis may play a complementary role in the pathophysiology of APs with the conventional amyloid cascade hypothesis. PMID:29439348

  13. Prenatal diagnosis and molecular characterization of a novel locus for Dandy-Walker malformation on chromosome 7p21.3.

    Science.gov (United States)

    Liao, Can; Fu, Fang; Li, Ru; Yang, Xin; Xu, Qing; Li, Dong-Zhi

    2012-01-01

    We present three foetuses with Dandy-Walker malformation, intra-uterine growth restriction and multiple congenital abnormalities, who were studied by array-based comparative genomic hybridization and revealed a novel locus on chromosome 7p21.3. The association of pure chromosome 7p aberrations with Dandy-Walker malformation has rarely been reported. The present study suggests that the critical region associated with Dandy-Walker malformation is restricted to 7p21.3, including the cerebellar disease associated genes NDUFA4 and PHF14. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  14. Diagnosis of a case of Dandy-Walker malformation aided by measurement of the brainstem-vermis angle at 14 weeks gestation.

    Science.gov (United States)

    Ichizuka, Kiyotake; Mishina, Miyuki; Hasegawa, Junichi; Matsuoka, Ryu; Sekizawa, Akihiko; Pooh, Ritsuko K

    2015-05-01

    Reported is a fetal Dandy-Walker malformation that was strongly suspected in the first trimester through measurement of the brainstem-vermis (B-V) angle, which was found to be 119° on transvaginal ultrasound examination at 14 weeks and 2 days gestation. Definitive diagnosis of the Dandy-Walker malformation was made by magnetic resonance imaging following stillbirth. Ultrasound measurement of the B-V angle may be a useful index for prenatal diagnosis of Dandy-Walker anomalies during early pregnancy. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  15. High-order evolving surface finite element method for parabolic problems on evolving surfaces

    OpenAIRE

    Kovács, Balázs

    2016-01-01

    High-order spatial discretisations and full discretisations of parabolic partial differential equations on evolving surfaces are studied. We prove convergence of the high-order evolving surface finite element method, by showing high-order versions of geometric approximation errors and perturbation error estimates and by the careful error analysis of a modified Ritz map. Furthermore, convergence of full discretisations using backward difference formulae and implicit Runge-Kutta methods are als...

  16. Localization Transition Induced by Learning in Random Searches

    Science.gov (United States)

    Falcón-Cortés, Andrea; Boyer, Denis; Giuggioli, Luca; Majumdar, Satya N.

    2017-10-01

    We solve an adaptive search model where a random walker or Lévy flight stochastically resets to previously visited sites on a d -dimensional lattice containing one trapping site. Because of reinforcement, a phase transition occurs when the resetting rate crosses a threshold above which nondiffusive stationary states emerge, localized around the inhomogeneity. The threshold depends on the trapping strength and on the walker's return probability in the memoryless case. The transition belongs to the same class as the self-consistent theory of Anderson localization. These results show that similarly to many living organisms and unlike the well-studied Markovian walks, non-Markov movement processes can allow agents to learn about their environment and promise to bring adaptive solutions in search tasks.

  17. Random Walks with Preferential Relocations to Places Visited in the Past and their Application to Biology

    Science.gov (United States)

    Boyer, Denis; Solis-Salas, Citlali

    2014-06-01

    Strongly non-Markovian random walks offer a promising modeling framework for understanding animal and human mobility, yet, few analytical results are available for these processes. Here we solve exactly a model with long range memory where a random walker intermittently revisits previously visited sites according to a reinforced rule. The emergence of frequently visited locations generates very slow diffusion, logarithmic in time, whereas the walker probability density tends to a Gaussian. This scaling form does not emerge from the central limit theorem but from an unusual balance between random and long-range memory steps. In single trajectories, occupation patterns are heterogeneous and have a scale-free structure. The model exhibits good agreement with data of free-ranging capuchin monkeys.

  18. Environmental noise, genetic diversity and the evolution of evolvability and robustness in model gene networks.

    Directory of Open Access Journals (Sweden)

    Christopher F Steiner

    Full Text Available The ability of organisms to adapt and persist in the face of environmental change is accepted as a fundamental feature of natural systems. More contentious is whether the capacity of organisms to adapt (or "evolvability" can itself evolve and the mechanisms underlying such responses. Using model gene networks, I provide evidence that evolvability emerges more readily when populations experience positively autocorrelated environmental noise (red noise compared to populations in stable or randomly varying (white noise environments. Evolvability was correlated with increasing genetic robustness to effects on network viability and decreasing robustness to effects on phenotypic expression; populations whose networks displayed greater viability robustness and lower phenotypic robustness produced more additive genetic variation and adapted more rapidly in novel environments. Patterns of selection for robustness varied antagonistically with epistatic effects of mutations on viability and phenotypic expression, suggesting that trade-offs between these properties may constrain their evolutionary responses. Evolution of evolvability and robustness was stronger in sexual populations compared to asexual populations indicating that enhanced genetic variation under fluctuating selection combined with recombination load is a primary driver of the emergence of evolvability. These results provide insight into the mechanisms potentially underlying rapid adaptation as well as the environmental conditions that drive the evolution of genetic interactions.

  19. Organic geochemistry and brine composition in Great Salt, Mono, and Walker Lakes

    Science.gov (United States)

    Domagalski, J.L.; Orem, W.H.; Eugster, H.P.

    1989-01-01

    Samples of Recent sediments, representing up to 1000 years of accumulation, were collected from three closed basin lakes (Mono Lake, CA, Walker Lake, NV, and Great Salt Lake, UT) to assess the effects of brine composition on the accumulation of total organic carbon, the concentration of dissolved organic carbon, humic acid structure and diagenesis, and trace metal complexation. The Great Salt Lake water column is a stratified Na-Mg-Cl-SO4 brine with low alkalinity. Algal debris is entrained in the high density (1.132-1.190 g/cc) bottom brines, and in this region maximum organic matter decomposition occurs by anaerobic processes, with sulfate ion as the terminal electron acceptor. Organic matter, below 5 cm of the sediment-water interface, degrades at a very slow rate in spite of very high pore-fluid sulfate levels. The organic carbon concentration stabilizes at 1.1 wt%. Mono Lake is an alkaline (Na-CO3-Cl-SO4) system. The water column is stratified, but the bottom brines are of lower density relative to the Great Salt Lake, and sedimentation of algal debris is rapid. Depletion of pore-fluid sulfate, near l m of core, results in a much higher accumulation of organic carbon, approximately 6 wt%. Walker Lake is also an alkaline system. The water column is not stratified, and decomposition of organic matter occurs by aerobic processes at the sediment-water interface and by anaerobic processes below. Total organic carbon and dissolved organic carbon concentrations in Walker Lake sediments vary with location and depth due to changes in input and pore-fluid sulfate concentrations. Nuclear magnetic resonance studies (13C) of humic substances and dissolved organic carbon provide information on the source of the Recent sedimentary organic carbon (aquatic vs. terrestrial), its relative state of decomposition, and its chemical structure. The spectra suggest an algal origin with little terrestrial signature at all three lakes. This is indicated by the ratio of aliphatic to

  20. Nasonia vitripennis (Walker (Hymenoptera: Pteromalidae parasitóide de dípteros muscóides coletado em Itumbiara, Goiás Nasonia vitripennis (Walker (Hymenoptera: Pteromalidae parasitoid of muscoids dipterous collected in Itumbiara, Goias, Brazil

    Directory of Open Access Journals (Sweden)

    C.H. Marchiori

    2004-06-01

    Full Text Available This work reports the occurrence of parasitoid Nasonia vitripennis (Walker (Hymenoptera: Pteromalidae parasitizing pupae of flies (Diptera in different substrata in Itumbiara, Goiás. The pupae were obtained by the flotation method. They were individually placed in gelatin capsules until the emergence of flies or their parasitoids. From May 1998 through April 2002, 737 parasitoids were collected in human feces, cattle liver, chicken, fish and cattle kidney. The prevalence of parasitism was 67.8%.

  1. Dynamical continuous time random Lévy flights

    Science.gov (United States)

    Liu, Jian; Chen, Xiaosong

    2016-03-01

    The Lévy flights' diffusive behavior is studied within the framework of the dynamical continuous time random walk (DCTRW) method, while the nonlinear friction is introduced in each step. Through the DCTRW method, Lévy random walker in each step flies by obeying the Newton's Second Law while the nonlinear friction f(v) = - γ0v - γ2v3 being considered instead of Stokes friction. It is shown that after introducing the nonlinear friction, the superdiffusive Lévy flights converges, behaves localization phenomenon with long time limit, but for the Lévy index μ = 2 case, it is still Brownian motion.

  2. Evolvability Is an Evolved Ability: The Coding Concept as the Arch-Unit of Natural Selection.

    Science.gov (United States)

    Janković, Srdja; Ćirković, Milan M

    2016-03-01

    Physical processes that characterize living matter are qualitatively distinct in that they involve encoding and transfer of specific types of information. Such information plays an active part in the control of events that are ultimately linked to the capacity of the system to persist and multiply. This algorithmicity of life is a key prerequisite for its Darwinian evolution, driven by natural selection acting upon stochastically arising variations of the encoded information. The concept of evolvability attempts to define the total capacity of a system to evolve new encoded traits under appropriate conditions, i.e., the accessible section of total morphological space. Since this is dependent on previously evolved regulatory networks that govern information flow in the system, evolvability itself may be regarded as an evolved ability. The way information is physically written, read and modified in living cells (the "coding concept") has not changed substantially during the whole history of the Earth's biosphere. This biosphere, be it alone or one of many, is, accordingly, itself a product of natural selection, since the overall evolvability conferred by its coding concept (nucleic acids as information carriers with the "rulebook of meanings" provided by codons, as well as all the subsystems that regulate various conditional information-reading modes) certainly played a key role in enabling this biosphere to survive up to the present, through alterations of planetary conditions, including at least five catastrophic events linked to major mass extinctions. We submit that, whatever the actual prebiotic physical and chemical processes may have been on our home planet, or may, in principle, occur at some time and place in the Universe, a particular coding concept, with its respective potential to give rise to a biosphere, or class of biospheres, of a certain evolvability, may itself be regarded as a unit (indeed the arch-unit) of natural selection.

  3. Field Studies of Streamflow Generation Using Natural and Injected Tracers on Bickford and Walker Branch Watersheds

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, D.

    1992-01-01

    Field studies of streamflow generation were undertaken on two forested watersheds, the West Road subcatchment of Bickford Watershed in central Massachusetts and the West Fork of Walker Branch Watershed in eastern Tennessee. A major component of the research was development of a two-stage methodology for the use of naturally-occurring {sup 222}Rn as a tracer. The first of the two stages was solving a mass-balance equation for {sup 222}Rn around a stream reach of interest in order to calculate [Rn]{sub q}, the {sup 222}Rn content of the lateral inflow to the reach; a conservative tracer (chloride) and a volatile tracer (propane) were injected into the study stream to account for lateral inflow to, and {sup 222}Rn volatilization from, the study reach. The second stage involved quantitative comparison of [Rn]{sub q} to the measured {sup 222}Rn concentrations of different subsurface waters in order to assess how important these waters were in contributing lateral inflow to the stream reach. The method was first applied to a 34 m stream reach at Bickford during baseflow; results suggested that {ge} 70% of the lateral inflow could be considered vadose zone water (water which had been in a saturated zone for less than a few days), and the remainder ''soil groundwater'' or ''saturated zone water'' (which had a longer residence time in a soil saturated zone). The method was then applied to two stream reaches on the West Fork of Walker Branch over a wide range of flow conditions; four springs were also investigated. It was found that springwater and inflow to the stream could be viewed as a mixture of water from three end members: the two defined at Bickford (vadose zone water and soil groundwater) and a third (bedrock groundwater) to account for the movement of water through fractured dolomite bedrock. Calcium was used as a second naturally-occurring tracer to distinguish bedrock groundwater from the other two end members. The behavior

  4. Prof. John Wood, Chief Executive Designate, Dr Gordon Walker, Directorate, Chief Executive, Prof. Ken J. Peach, Head of the Particle Physics Department, CLRC Rutherford Appleton Laboratory, United Kingdom

    CERN Document Server

    Patrice Loïez

    2001-01-01

    L. to. r.: Dr. Ian Wilson, CLIC Deputy Study Leader, Prof. Ken J. Peach, Head of the Particle Physics Department, Prof. John Wood, Chief Executive Designate, Dr. Gordon Walker, Directorate, Chief Executive

  5. Survivability is more fundamental than evolvability.

    Directory of Open Access Journals (Sweden)

    Michael E Palmer

    Full Text Available For a lineage to survive over long time periods, it must sometimes change. This has given rise to the term evolvability, meaning the tendency to produce adaptive variation. One lineage may be superior to another in terms of its current standing variation, or it may tend to produce more adaptive variation. However, evolutionary outcomes depend on more than standing variation and produced adaptive variation: deleterious variation also matters. Evolvability, as most commonly interpreted, is not predictive of evolutionary outcomes. Here, we define a predictive measure of the evolutionary success of a lineage that we call the k-survivability, defined as the probability that the lineage avoids extinction for k generations. We estimate the k-survivability using multiple experimental replicates. Because we measure evolutionary outcomes, the initial standing variation, the full spectrum of generated variation, and the heritability of that variation are all incorporated. Survivability also accounts for the decreased joint likelihood of extinction of sub-lineages when they 1 disperse in space, or 2 diversify in lifestyle. We illustrate measurement of survivability with in silico models, and suggest that it may also be measured in vivo using multiple longitudinal replicates. The k-survivability is a metric that enables the quantitative study of, for example, the evolution of 1 mutation rates, 2 dispersal mechanisms, 3 the genotype-phenotype map, and 4 sexual reproduction, in temporally and spatially fluctuating environments. Although these disparate phenomena evolve by well-understood microevolutionary rules, they are also subject to the macroevolutionary constraint of long-term survivability.

  6. Henri Cartier-Bresson / Walker Evans : Photographier l’Amérique (1929-1947

    Directory of Open Access Journals (Sweden)

    François Brunet

    2009-08-01

    Full Text Available Dans un mot adressé en 2001 à Peter Galassi, conservateur de la photographie au MOMA, Henri Cartier-Bresson, alors âgé de quatre-vingt-treize ans, écrivait plaisamment — mais non pas complaisamment : « If it had not been for the challenge of the work of Walker Evans, I don’t think I would have remained a fotographer » (« sans le défi constitué par le travail de Walker Evans, je ne crois pas que je serais resté fotographe ». Pour fêter le centenaire de Cartier-Bresson, c’est ce défi — plutôt ...

  7. Biological aspects of Periga circumstans Walker, 1855 (Lepidoptera: Saturniidae: Hemileucinae with larvae reared on khaki and mate-plant leaves

    Directory of Open Access Journals (Sweden)

    A. Specht

    Full Text Available The goal of the present study was to investigate biological aspects of Periga circumstans Walker, 1855 (Lepidoptera: Saturniidae: Hemileucinae whose larvae were fed on leaves of khaki-plant (Diospyros khaki Linnaeus - Ebenaceae and Mate-plant (Ilex paraguariensis Saint Hilaire - Aquifoliaceae leaves. The biological parameters were obtained from specimens kept under controlled conditions: temperature of 25 ± 1 °C, relative humidity of 70 ± 10%, and photoperiod of 12 hours. For each developmental stage, morphological and ethological parameters are described. The larvae passed through six instars with a growth average rate of 1.4 for each instar. The host plants influenced significantly only the total duration of the larval phase, which was prolonged for larvae fed on khaki-plant leaves. Several aspects related to the morphology and the ethology of P. circumstans are similar to those described for Lonomia obliqua Walker, 1855.

  8. Seizure and unilateral facial nerve paralysis in a newborn with Dandy-Walker malformation – A case report

    Directory of Open Access Journals (Sweden)

    Subhajit Bhakta

    2014-01-01

    Full Text Available The Dandy-Walker syndrome (DWS is a rare posterior fossa malformation. It can have a varied presentation depending on the age. A newborn presenting with neonatal seizure along with unilateral facial nerve palsy is rather a rare presentation of DWS and very few such cases were reported in the past. We are reporting a case of a newborn male baby presenting with neonatal seizure within 48 hrs of birth along with right sided LMN type facial nerve palsy which on due course of investigation revealed as a case of Dandy–Walker malformation. Journal of College of Medical Sciences-Nepal, 2013, Vol-9, No-1, 48-51 DOI: http://dx.doi.org/10.3126/jcmsn.v9i1.9673

  9. A New Anatomic Variation: Coexistence of Both Dandy-Walker Variant and Ophthalmic Artery Originating From Contralateral Internal Carotid Artery.

    Science.gov (United States)

    Ogul, Hayri; Havan, Nuri; Gedikli, Yusuf; Pirimoglu, Berhan; Kantarci, Mecit

    2016-06-01

    The authors report on 1 patient of variant origin of right ophthalmic artery (OA) from ophthalmic segment of the left internal carotid artery. A 41-year-old man was performed magnetic resonance (MR) imaging and MR angiography. Cerebral MR imaging revealed a Dandy-Walker variant. In MR angiography the authors observed this unusual variant of origin of OA and a complete occlusion of right internal carotid artery. To the authors' knowledge, this is the first patient who has coincidence of both Dandy-Walker variant and origin of OA from contralateral internal carotid artery. Careful observation of MR angiography images with maximum intensity projection is very important for detecting rare vascular variations.

  10. Present weather and climate: evolving conditions

    Science.gov (United States)

    Hoerling, Martin P; Dettinger, Michael; Wolter, Klaus; Lukas, Jeff; Eischeid, Jon K.; Nemani, Rama; Liebmann, Brant; Kunkel, Kenneth E.

    2013-01-01

    This chapter assesses weather and climate variability and trends in the Southwest, using observed climate and paleoclimate records. It analyzes the last 100 years of climate variability in comparison to the last 1,000 years, and links the important features of evolving climate conditions to river flow variability in four of the region’s major drainage basins. The chapter closes with an assessment of the monitoring and scientific research needed to increase confidence in understanding when climate episodes, events, and phenomena are attributable to human-caused climate change.

  11. f( R) gravity solutions for evolving wormholes

    Science.gov (United States)

    Bhattacharya, Subhra; Chakraborty, Subenoy

    2017-08-01

    The scalar-tensor f( R) theory of gravity is considered in the framework of a simple inhomogeneous space-time model. In this research we use the reconstruction technique to look for possible evolving wormhole solutions within viable f( R) gravity formalism. These f( R) models are then constrained so that they are consistent with existing experimental data. Energy conditions related to the matter threading the wormhole are analyzed graphically and are in general found to obey the null energy conditions (NEC) in regions around the throat, while in the limit f(R)=R, NEC can be violated at large in regions around the throat.

  12. Information theory, evolutionary innovations and evolvability.

    Science.gov (United States)

    Wagner, Andreas

    2017-12-05

    How difficult is it to 'discover' an evolutionary adaptation or innovation? I here suggest that information theory, in combination with high-throughput DNA sequencing, can help answer this question by quantifying a new phenotype's information content. I apply this framework to compute the phenotypic information associated with novel gene regulation and with the ability to use novel carbon sources. The framework can also help quantify how DNA duplications affect evolvability, estimate the complexity of phenotypes and clarify the meaning of 'progress' in Darwinian evolution.This article is part of the themed issue 'Process and pattern in innovations from cells to societies'. © 2017 The Author(s).

  13. [Reseña] Charles F. Walker, Smoldering ashes: Cusco and the creation of Republican Peru, 1780-1840

    OpenAIRE

    Latasa, P. (Pilar)

    2002-01-01

    Reseña del libro de Walker, Charles F.: De Túpac Amaru a Gamarra: Cusco y la formación del Perú Republicano, 1780-1840, Cusco, Centro de Estudios Regionales Andinos “Bartolomé de Las Casas”, 1999, 316 págs. [Smoldering ashes: Cusco and the creation of Republican Peru, 1780-1840, Durham, N.C., Duke University Press, 1999].

  14. New Lethal Skeletal Dysplasia with Dandy-Walker Malformation, Congenital Heart Defects, Abnormal Thumbs, Hypoplastic Genitalia, and Distinctive Facies

    Science.gov (United States)

    Stevens, Cathy A.; Lachman, Ralph S.

    2011-01-01

    We report on two sibs with a lethal form of bone dysplasia with distinctive skeletal findings including rhizomelic and mesomelic limb shortening, hooked clavicles, dumbbell femurs, and absence of talus and calcaneus ossification. Other clinical features include Dandy-Walker malformation, congenital heart defects, joint contractures, genital hypoplasia, and distinctive facial features. These sibs appear to have a previously undescribed skeletal dysplasia, which is most likely inherited in an autosomal recessive fashion. PMID:20602491

  15. Hybridization between multi-objective genetic algorithm and support vector machine for feature selection in walker-assisted gait.

    Science.gov (United States)

    Martins, Maria; Costa, Lino; Frizera, Anselmo; Ceres, Ramón; Santos, Cristina

    2014-03-01

    Walker devices are often prescribed incorrectly to patients, leading to the increase of dissatisfaction and occurrence of several problems, such as, discomfort and pain. Thus, it is necessary to objectively evaluate the effects that assisted gait can have on the gait patterns of walker users, comparatively to a non-assisted gait. A gait analysis, focusing on spatiotemporal and kinematics parameters, will be issued for this purpose. However, gait analysis yields redundant information that often is difficult to interpret. This study addresses the problem of selecting the most relevant gait features required to differentiate between assisted and non-assisted gait. For that purpose, it is presented an efficient approach that combines evolutionary techniques, based on genetic algorithms, and support vector machine algorithms, to discriminate differences between assisted and non-assisted gait with a walker with forearm supports. For comparison purposes, other classification algorithms are verified. Results with healthy subjects show that the main differences are characterized by balance and joints excursion in the sagittal plane. These results, confirmed by clinical evidence, allow concluding that this technique is an efficient feature selection approach. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. How do walkers behave when crossing the way of a mobile robot that replicates human interaction rules?

    Science.gov (United States)

    Vassallo, Christian; Olivier, Anne-Hélène; Souères, Philippe; Crétual, Armel; Stasse, Olivier; Pettré, Julien

    2018-02-01

    Previous studies showed the existence of implicit interaction rules shared by human walkers when crossing each other. Especially, each walker contributes to the collision avoidance task and the crossing order, as set at the beginning, is preserved along the interaction. This order determines the adaptation strategy: the first arrived increases his/her advance by slightly accelerating and changing his/her heading, whereas the second one slows down and moves in the opposite direction. In this study, we analyzed the behavior of human walkers crossing the trajectory of a mobile robot that was programmed to reproduce this human avoidance strategy. In contrast with a previous study, which showed that humans mostly prefer to give the way to a non-reactive robot, we observed similar behaviors between human-human avoidance and human-robot avoidance when the robot replicates the human interaction rules. We discuss this result in relation with the importance of controlling robots in a human-like way in order to ease their cohabitation with humans. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Metabolic effects of Hedyotis diffusa on rats bearing Walker 256 tumor revealed by NMR-based metabolomics.

    Science.gov (United States)

    Wang, Zhiyong; Gao, Kuo; Xu, Can; Gao, Jian; Yan, Yujing; Wang, Yingfeng; Li, Zhongfeng; Chen, Jianxin

    2017-08-28

    Hedyotis diffusa, a traditional Chinese herbal medicine, is widely used for oncotherapy and shows a positive effect in the clinical treatment. But its mechanism of anticancer activities is complicated and unclear. This study was undertaken to assess the therapeutic effects and reveal detailed mechanisms of H. diffusa for oncotherapy. A Walker 256 tumor-bearing rat model was established, and metabolomic profiles of plasma and urine were obtained from (1) H NMR technique. Multivariate statistical analysis methods were used to characterize the discriminating metabolites between control (C), Walker 256 tumor-bearing rats model (M), and H. diffusa treatment (H) groups. Finally, 13 and 10 metabolomic biomarkers in urine and plasma samples were further identified as characteristic metabolites in M group, whereas H group showed a partial metabolic balance recovered, such as ornithine, N-acetyl-l-aspartate, l-aspartate, and creatinine in urine samples, and acetate, lactate, choline, l-glutamine, and 3-hydroxybutyrate in plasma samples. On the basis of the methods above, we hypothesized H. diffusa treatment reduced the injury caused by Walker 256 tumor and maintained a metabolic balance. Our study demonstrated that this method provided new insights into metabolic alterations in tumor-bearing biosystems and researching on the effects of H. diffusa on the endogenous metabolism in tumor-bearing rats. Copyright © 2017 John Wiley & Sons, Ltd.

  18. Dandy-Walker malformation associated with heterozygous ZIC1 and ZIC4 deletion: Report of a new patient.

    Science.gov (United States)

    Tohyama, Jun; Kato, Mitsuhiro; Kawasaki, Sari; Harada, Naoki; Kawara, Hiroki; Matsui, Takeshi; Akasaka, Noriyuki; Ohashi, Tsukasa; Kobayashi, Yu; Matsumoto, Naomichi

    2011-01-01

    We report on a female patient with Dandy-Walker malformation possibly caused by heterozygous loss of ZIC1 and ZIC4. The patient presented with mental retardation, epilepsy, and multiple congenital malformations including spina bifida, mild dysmorphic facial features including, thick eyebrows, broad nose, full lips, macroglossia, and hypoplasia of the cerebellar vermis with enlargement of the fourth ventricle on brain magnetic resonance imaging, which is consistent with Dandy-Walker malformation. A chromosome analysis showed interstitial deletion of chromosome 3q23-q25.1. Fluorescence in situ hybridization (FISH) and microarray-based genomic analysis revealed the heterozygous deletion of ZIC1 and ZIC4 loci on 3q24. Her facial features were not consistent with those observed in blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) involving FOXL2 abnormality. Other deleted genes at 3q23-25.1 might contribute to the dysmorphic facial appearance. A milder phenotype as the Dandy-Walker malformation in our patient supports the idea that modifying loci/genes can influence the development of cerebellar malformation. Copyright © 2010 Wiley-Liss, Inc.

  19. Netgram: Visualizing Communities in Evolving Networks.

    Directory of Open Access Journals (Sweden)

    Raghvendra Mall

    Full Text Available Real-world complex networks are dynamic in nature and change over time. The change is usually observed in the interactions within the network over time. Complex networks exhibit community like structures. A key feature of the dynamics of complex networks is the evolution of communities over time. Several methods have been proposed to detect and track the evolution of these groups over time. However, there is no generic tool which visualizes all the aspects of group evolution in dynamic networks including birth, death, splitting, merging, expansion, shrinkage and continuation of groups. In this paper, we propose Netgram: a tool for visualizing evolution of communities in time-evolving graphs. Netgram maintains evolution of communities over 2 consecutive time-stamps in tables which are used to create a query database using the sql outer-join operation. It uses a line-based visualization technique which adheres to certain design principles and aesthetic guidelines. Netgram uses a greedy solution to order the initial community information provided by the evolutionary clustering technique such that we have fewer line cross-overs in the visualization. This makes it easier to track the progress of individual communities in time evolving graphs. Netgram is a generic toolkit which can be used with any evolutionary community detection algorithm as illustrated in our experiments. We use Netgram for visualization of topic evolution in the NIPS conference over a period of 11 years and observe the emergence and merging of several disciplines in the field of information processing systems.

  20. Evolving MEMS Resonator Designs for Fabrication

    Science.gov (United States)

    Hornby, Gregory S.; Kraus, William F.; Lohn, Jason D.

    2008-01-01

    Because of their small size and high reliability, microelectromechanical (MEMS) devices have the potential to revolution many areas of engineering. As with conventionally-sized engineering design, there is likely to be a demand for the automated design of MEMS devices. This paper describes our current status as we progress toward our ultimate goal of using an evolutionary algorithm and a generative representation to produce designs of a MEMS device and successfully demonstrate its transfer to an actual chip. To produce designs that are likely to transfer to reality, we present two ways to modify evaluation of designs. The first is to add location noise, differences between the actual dimensions of the design and the design blueprint, which is a technique we have used for our work in evolving antennas and robots. The second method is to add prestress to model the warping that occurs during the extreme heat of fabrication. In future we expect to fabricate and test some MEMS resonators that are evolved in this way.

  1. Netgram: Visualizing Communities in Evolving Networks

    Science.gov (United States)

    Mall, Raghvendra; Langone, Rocco; Suykens, Johan A. K.

    2015-01-01

    Real-world complex networks are dynamic in nature and change over time. The change is usually observed in the interactions within the network over time. Complex networks exhibit community like structures. A key feature of the dynamics of complex networks is the evolution of communities over time. Several methods have been proposed to detect and track the evolution of these groups over time. However, there is no generic tool which visualizes all the aspects of group evolution in dynamic networks including birth, death, splitting, merging, expansion, shrinkage and continuation of groups. In this paper, we propose Netgram: a tool for visualizing evolution of communities in time-evolving graphs. Netgram maintains evolution of communities over 2 consecutive time-stamps in tables which are used to create a query database using the sql outer-join operation. It uses a line-based visualization technique which adheres to certain design principles and aesthetic guidelines. Netgram uses a greedy solution to order the initial community information provided by the evolutionary clustering technique such that we have fewer line cross-overs in the visualization. This makes it easier to track the progress of individual communities in time evolving graphs. Netgram is a generic toolkit which can be used with any evolutionary community detection algorithm as illustrated in our experiments. We use Netgram for visualization of topic evolution in the NIPS conference over a period of 11 years and observe the emergence and merging of several disciplines in the field of information processing systems. PMID:26356538

  2. BOOK REVIEW: OPENING SCIENCE, THE EVOLVING GUIDE ...

    Science.gov (United States)

    The way we get our funding, collaborate, do our research, and get the word out has evolved over hundreds of years but we can imagine a more open science world, largely facilitated by the internet. The movement towards this more open way of doing and presenting science is coming, and it is not taking hundreds of years. If you are interested in these trends, and would like to find out more about where this is all headed and what it means to you, consider downloding Opening Science, edited by Sönke Bartling and Sascha Friesike, subtitled The Evolving Guide on How the Internet is Changing Research, Collaboration, and Scholarly Publishing. In 26 chapters by various authors from a range of disciplines the book explores the developing world of open science, starting from the first scientific revolution and bringing us to the next scientific revolution, sometimes referred to as “Science 2.0”. Some of the articles deal with the impact of the changing landscape of how science is done, looking at the impact of open science on Academia, or journal publishing, or medical research. Many of the articles look at the uses, pitfalls, and impact of specific tools, like microblogging (think Twitter), social networking, and reference management. There is lots of discussion and definition of terms you might use or misuse like “altmetrics” and “impact factor”. Science will probably never be completely open, and Twitter will probably never replace the journal article,

  3. Synopsis of the 6th Walker's Cay Colloquium on Cancer Vaccines and Immunotherapy

    Directory of Open Access Journals (Sweden)

    Marincola Francesco M

    2004-06-01

    Full Text Available Abstract The 6th annual Cancer Vaccines and Immunotherapy Colloquium at Walker's Cay was held under the auspices of the Albert B. Sabin Vaccine Institute on March 10–13, 2004. The Colloquium consisted of a select group of 34 scientists representing academia, biotechnology and pharmaceutical industry. The main goal of this gathering was to promote in a peaceful and comfortable environment exchanges between basic and clinical science. The secondary benefit was to inspire novel bench to bedside ventures and at the same time provide feed back about promising and/or disappointing clinical results that could help re-frame some scientific question or guide the design of future trials. Several topics were covered that included tumor antigen discovery and validation, platforms for vaccine development, tolerance, immune suppression and tumor escape mechanisms, adoptive T cell therapy and dendritic cell-based therapies, clinical trials and assessment of response. Here we report salient points raised by speakers or by the audience during animated discussion that followed each individual presentation.

  4. Discrimination of locomotion direction in impoverished displays of walkers by macaque monkeys.

    Science.gov (United States)

    Vangeneugden, Joris; Vancleef, Kathleen; Jaeggli, Tobias; VanGool, Luc; Vogels, Rufin

    2009-04-28

    A vast literature exists on human biological motion perception in impoverished displays, e.g., point-light walkers. Less is known about the perception of impoverished biological motion displays in macaques. We trained 3 macaques in the discrimination of facing direction (left versus right) and forward versus backward walking using motion-capture-based locomotion displays (treadmill walking) in which the body features were represented by cylinder-like primitives. The displays did not contain translatory motion. Discriminating forward versus backward locomotion requires motion information while the facing-direction/view task can be solved using motion and/or form. All monkeys required lengthy training to learn the forward-backward task, while the view task was learned more quickly. Once acquired, the discriminations were specific to walking and stimulus format but generalized across actors. Although the view task could be solved using form cues, there was a small impact of motion. Performance in the forward-backward task was highly susceptible to degradations of spatiotemporal stimulus coherence and motion information. These results indicate that rhesus monkeys require extensive training in order to use the intrinsic motion cues related to forward versus backward locomotion and imply that extrapolation of observations concerning human perception of impoverished biological motion displays onto monkey perception needs to be made cautiously.

  5. Purification and characterization of hemocyte phenoloxidases in Chilo suppressalis walker (Lepidoptera: Crambidae

    Directory of Open Access Journals (Sweden)

    Mirhaghparast Seyyedeh Kimia

    2015-01-01

    Full Text Available In the current study, two phenoloxidases (POs from the larvae of Chilo suppressalis Walker were extracted and purified by column chromatography using Sepharyl G-100 and DEAE-Cellulose fast flow column. Two proteins possessing PO activity, named as POI and POII, were extracted by purification, 5.08- and 5.62-fold, respectively, with 8.94% and 7.31% recoveries, respectively. Also, the specific activities of POI and POII were 0.478 and 0.529 U/mg protein, respectively. Finally, the molecular weights of POI and POII were calculated as 94.6 and 95.7 kDa, respectively. Kinetic parameters of the purified phenoloxidases by Lineweaver-Burk analysis were Vmax of 2.27 and 1.11 U/mg protein and Km of 15.51 and 17.31 mM for POI and POII, respectively. Mg2+ and Cu2+ significantly increased the PO activities. Ca2+ decreased the activity of POI and showed no statistical effects on POII activity. EDTA and DTC significantly inhibited the activities of the purified enzymes, while triethylenetetramine hexaacetic acid (TTHA and RGTA showed no significant effects on enzymatic activities.

  6. Platynota rostrana (Walker (Tortricidae and Phidotricha erigens Raganot (Pyralidae: artificial diet effects on biological cycle

    Directory of Open Access Journals (Sweden)

    D. E. Nava

    Full Text Available The lepidopterans Platynota rostrana (Walker (Tortricidae and Phidotricha erigens Raganot (Pyralidae have been found frequently in citrus groves in São Paulo State in recent years. Since in Brazil, the fertility cycle of these two species is largely unknown, as are details of the damage wrought by them in crops, this research studied these aspects of the two species, which were kept under laboratory conditions (temperature 25 ± 2 °C, 70 ± 10% RH, 14 h photophase and on an artificial diet. The duration of the biological cycle (egg-adult for P. rostrana was 38.3 days and total viability was 44.0%; for P. erigens these values were 32.5 days and 63.6%, respectively. Both species showed five larval instars. Females of P. rostrana laid an average of 308 eggs, whereas those of P. erigens laid an average of 106 eggs. In both species, female pupae were heavier than males. Male and female longevity for both species was nearly 10 days. Based on the data obtained, the artificial diet produced better results in P. rostrana than in P. erigens. If these species, which have the potential to reach pest status in the citrus groves of São Paulo State, could be reared on an artificial diet, research on their control by alternative methods would be easier.

  7. Approximate KMS states for scalar and spinor fields in Friedmann-Robertson-Walker spacetimes

    Energy Technology Data Exchange (ETDEWEB)

    Dappiaggi, Claudio; Hack, Thomas-Paul [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik; Pinamonti, Nicola [Roma ' ' Tor Vergata' ' Univ. (Italy). Dipt. di Matematica

    2010-09-15

    We construct and discuss Hadamard states for both scalar and Dirac spinor fields in a large class of spatially flat Friedmann-Robertson-Walker spacetimes characterised by an initial phase either of exponential or of power-law expansion. The states we obtain can be interpreted as being in thermal equilibrium at the time when the scale factor a has a specific value a = a{sub 0}. In the case a{sub 0} = 0, these states fulfil a strict KMS condition on the boundary of the spacetime, which is either a cosmological horizon, or a Big Bang hypersurface. Furthermore, in the conformally invariant case, they are conformal KMS states on the full spacetime. However, they provide a natural notion of an approximate KMS state also in the remaining cases, especially for massive fields. On the technical side, our results are based on a bulk-to-boundary reconstruction technique already successfully applied in the scalar case and here proven to be suitable also for spinor fields. The potential applications of the states we find range over a broad spectrum, but they appear to be suited to discuss in particular thermal phenomena such as the cosmic neutrino background or the quantum state of dark matter. (orig.)

  8. Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Mauricio [Departamento de Fisica, Universidad del Bio-Bio, Avenida Collao 1202, Casilla 5-C, Concepcion (Chile)], E-mail: mcataldo@ubiobio.cl; Mella, Patricio [Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)], E-mail: patriciomella@udec.cl; Minning, Paul [Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)], E-mail: pminning@udec.cl; Saavedra, Joel [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4950, Valparaiso (Chile)], E-mail: joel.saavedra@ucv.cl

    2008-05-01

    We provide a detailed description for power-law scaling Friedmann-Robertson-Walker cosmological scenarios dominated by two interacting perfect fluid components during the expansion. As a consequence of the mutual interaction between the two fluids, neither component is conserved separately and the energy densities are proportional to 1/t{sup 2}. It is shown that in flat FRW cosmological models there can exist interacting superpositions of two perfect fluids (each of them having a positive energy density) which accelerate the expansion of the universe. In this family there also exist flat power-law cosmological scenarios where one of the fluids may have a 'cosmological constant' or 'vacuum energy' equation of state (p=-{rho}) interacting with the other component; this scenario exactly mimics the behavior of the standard flat Friedmann solution for a single fluid with a barotropic equation of state. These possibilities of combining interacting perfect fluids do not exist for the non-interacting mixtures of two perfect cosmic fluids, where the general solution for the scale factor is not described by power-law expressions and has a more complicated behavior. In this study is considered also the associated single fluid model interpretation for the interaction between two fluids.

  9. Fitness test profiles and trainng intensities in skilled race-walkers.

    Science.gov (United States)

    Reilly, T; Hopkins, J; Howlett, N

    1979-06-01

    A broad profile of national standard race-walkers was obtained. Subjects were taller and had more body fat than competitive runners of comparable distance as found in the literature. Pulmonary function, blood pressure and maximal heart rates were similar to normal sedentary values. The group's somatotype was 2.5 : 3 : 4, low mesomorphy being reflected in inferior strength measures. Haematological status corresponded to the runners of Brotherhood et al (1975). Predicted VO2 max (x = 70 ml kg min-1) was not related to performance. Time to exhaustion on a treadmill test correlated with 20 km race time (R = -.94; p less than .001). Multiple regression equations derived to predict race performance from combinations of 4 to 6 personality traits were non-significant. Mean heart rate in typical training regimes was 167 beats min-1 for interval training at 13 kmh-1 on the track and 134 beats min-1 over a 2.1 h road walk at 10.3 kmh-1. Physiological strain was greater in uphill than in level or downhill walking (P less than .001).

  10. Biotic potential, fertility and life table ofSpodoptera albula (Walker (Lepidoptera: Noctuidae, under controlled conditions

    Directory of Open Access Journals (Sweden)

    DÉBORA G. MONTEZANO

    2014-06-01

    Full Text Available This study aimed to evaluate the biotic potential, life table parameters and fertility of Spodoptera albula (Walker, 1857 under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photo phase. The longevity, pre, post and oviposition periods, fecundity and fertility of 13 couples were evaluated. The longevity of females (13.500 days was significantly higher than those of males (11.154 days. The mean durations of the pre, post and oviposition periods were 2.615, 1.769 and 9.385 days, respectively. The mean fecundity was 1.417.69 eggs and mean fertility was 1.340.401 larvae, per female. On average, females copulated 1, 231 times. A strong positive correlation was observed between the number of copulations and fecundity (r = 0.847, p <0.001, as well as a strong negative correlation between the number of copulations and the duration of the pre-oviposition period (r = -0.762, p = 0.002, and longevity (r = -0.788, p = 0.001. The biotic potential of S. albula was estimated at 8.768 x 1022 individuals / female / year. The net reproductive rate (Ro was 353,904 times per generation and the mean generation time (T was 37.187 days. The intrinsic rate of increase (rm was 1,105, with a finite rate of increase (λ of 3,019.

  11. A measure on the set of compact Friedmann-Lemaitre-Robertson-Walker models

    Energy Technology Data Exchange (ETDEWEB)

    Roukema, Boudewijn F [Torun Centre for Astronomy, Nicolaus Copernicus University, ul. Gagarina 11, 87-100 Torun (Poland); Blanloeil, Vincent [IRMA, Departement de Mathematiques, Universite de Strasbourg, 7 rue Rene Descartes, 67084 Strasbourg, Cedex (France)

    2010-12-21

    Compact, flat Friedmann-Lemaitre-Robertson-Walker (FLRW) models have recently regained interest as a good fit to the observed cosmic microwave background temperature fluctuations. However, it is generally thought that a globally, exactly flat FLRW model is theoretically improbable. Here, in order to obtain a probability space on the set F of compact, comoving, 3-spatial sections of FLRW models, a physically motivated hypothesis is proposed, using the density parameter {Omega} as a derived rather than fundamental parameter. We assume that the processes that select the 3-manifold also select a global mass-energy and a Hubble parameter. The requirement that the local and global values of {Omega} are equal implies a range in {Omega} that consists of a single real value for any 3-manifold. Thus, the obvious measure over F is the discrete measure. Hence, if the global mass-energy and Hubble parameter are a function of 3-manifold choice among compact FLRW models, then probability spaces parametrized by {Omega} do not, in general, give a zero probability of a flat model. Alternatively, parametrization by a spatial size parameter, the injectivity radius r{sub inj}, suggests the Lebesgue measure. In this case, the probability space over the injectivity radius implies that flat models occur almost surely (a.s.), in the sense of probability theory, and non-flat models a.s. do not occur.

  12. Cortical regions for judgments of emotions and personality traits from point-light walkers.

    Science.gov (United States)

    Heberlein, Andrea S; Adolphs, Ralph; Tranel, Daniel; Damasio, Hanna

    2004-09-01

    Humans are able to use nonverbal behavior to make fast, reliable judgments of both emotional states and personality traits. Whereas a sizeable body of research has identified neural structures critical for emotion recognition, the neural substrates of personality trait attribution have not been explored in detail. In the present study, we investigated the neural systems involved in emotion and personality trait judgments. We used a type of visual stimulus that is known to convey both emotion and personality information, namely, point-light walkers. We compared the emotion and personality trait judgments made by subjects with brain damage to those made by neurologically normal subjects and then conducted a lesion overlap analysis to identify neural regions critical for these two tasks. Impairments on the two tasks dissociated: Some subjects were impaired at emotion recognition, but judged personality normally; other subjects were impaired on the personality task, but normal at emotion recognition. Moreover, these dissociations in performance were associated with damage to specific neural regions: Right somatosensory cortices were a primary focus of lesion overlap in subjects impaired on the emotion task, whereas left frontal opercular cortices were a primary focus of lesion overlap in subjects impaired on the personality task. These findings suggest that attributions of emotional states and personality traits are accomplished by partially dissociable neural systems.

  13. Description and field performance of the Walker Branch throughfall displacement experiment: 1993--1996

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, P.J.; Todd, D.E.; Huston, M.A. [Oak Ridge National lab., TN (United States). Environmental Sciences Div.; Joslin, J.D. [Tennessee Valley Authority, Norris, TN (United States); Croker, J.L.; Auge, R.M. [Univ. of Tennessee, Knoxville, TN (United States). Inst. of Agriculture

    1998-04-01

    The authors are conducting a large-scale manipulative field experiment in an upland oak forest on the Walker Branch Watershed in eastern Tennessee to identify important ecosystem responses that might result from future precipitation changes. The manipulation of soil water content is being implemented by a gravity-driven transfer of throughfall from one 6400-m{sup 2} treatment plot to another. Throughfall is intercepted in {approx}1850 subcanopy troughs suspended above the forest floor of the dry plot and transferred by gravity flow across an ambient plot for subsequent distribution onto the wet treatment plot. Soil water content is being monitored at two depths with time domain reflectometers at 310 sampling locations across the site. The experimental system is able to produce statistically significant differences in soil water content in years having both dry and wet conditions. Maximum soil water content differentials between wet and dry plots in the 0- to 0.35-m horizon were 8 to 10% during summers with abundant precipitation and 3 to 5% during drought periods. Treatment impacts on soil water potential were restricted to the surface soil layer. Comparisons of pre- and post-installation soil and litter temperature measurements showed the ability of the experimental design to produce changes in soil water content and water potential without creating large artifacts in the forest understory environment.

  14. An Acquired Form of Dandy-Walker Malformation with Enveloping Hemosiderin Deposits

    Directory of Open Access Journals (Sweden)

    Tadashi Shiohama

    2017-01-01

    Full Text Available Dandy-Walker malformation (DWM is a posterior fossa anomaly characterized by hypoplasia and upward rotation of the cerebellar vermis and cystic dilation of the fourth ventricle. The cyst of DWM rarely extends posteriorly to almost completely fill the entire posterior fossa, which mimics primary cerebellar agenesis, a cerebellar porencephalic cyst, and an arachnoid cyst due to the lack of clarity of the thin cystic wall. A 10-month-old female born at 23 weeks’ gestation with cerebellar hemorrhage in the neonatal period was admitted to our hospital with dysphagia and side-to-side head bobbing. The detection of hemosiderin deposits enveloping the cyst wall by T2 star-weighted angiography (SWAN was useful for the differential diagnosis of an acquired form of DWM from primary cerebellar agenesis. Cyst fenestration successfully improved dysphagia and head bobbing. A pathological specimen of the perforated cyst consisted of collagen fibers with hemosiderin deposits but lacked congenital cyst components. In infants with posterior fossa cysts, SWAN will be useful for a differential diagnosis between DWM and primary cerebellar agenesis.

  15. Chronic Glibenclamide Treatment Attenuates Walker-256 Tumour Growth in Prediabetic Obese Rats

    Directory of Open Access Journals (Sweden)

    Claudinéia Conationi da Silva Franco

    2017-05-01

    Full Text Available Background/Aims: The sulphonylurea glibenclamide (Gli is widely used in the treatment of type 2 diabetes. In addition to its antidiabetic effects, low incidences of certain types of cancer have been observed in Gli-treated diabetic patients. However, the mechanisms underlying this observation remain unclear. The aim of the present work was to evaluate whether obese adult rats that were chronically treated with an antidiabetic drug, glibenclamide, exhibit resistance to rodent breast carcinoma growth. Methods: Neonatal rats were treated with monosodium L-glutamate (MSG to induce prediabetes. Control and MSG groups were treated with Gli (2 mg/kg body weight/day from weaning to 100 days old. After Gli treatment, the control and MSG rats were grafted with Walker-256 tumour cells. After 14 days, grafted rats were euthanized, and tumour weight as well as glucose homeostasis were evaluated. Results: Treatment with Gli normalized tissue insulin sensitivity and glucose tolerance, suppressed fasting hyperinsulinaemia, reduced fat tissue accretion in MSG rats, and attenuated tumour growth by 27% in control and MSG rats. Conclusions: Gli treatment also resulted in a large reduction in the number of PCNA-positive tumour cells. Although treatment did improve the metabolism of pre-diabetic MSG-rats, tumour growth inhibition may be a more direct effect of glibenclamide.

  16. Long-term follow-up of successful treatment for dandy-walker syndrome (DWS).

    Science.gov (United States)

    Lin, Jun; Liang, Guobiao; Liang, Yong; Kou, Yun

    2015-01-01

    Various managements of Dandy-Walker syndrome (DWS) from open excision of the cysts to CSF diversion have been reported. However, optimal treatment for DWS remains elusive. Cyst fenestration was employed firstly, but failed 15 days after the surgery. Then a ventriculoperitoneal (VP) shunt was inserted and the patient discharged from hospital 13 days after the second surgery. During the 12-year follow-up, CT scanning, MRI, and X-radiation were performed. CT scanning showed that the size of ventricular system gradually returned to normal. MRI revealed similar changes of the ventricular system, and further revealed the development of supratentorial brain. The results of X-radiation during the follow-up years showed that the peritoneal end of the shunt might be already out of the abdominal cavity. Slow refilling of the shunt valve may suggest that the shunt could be probably not functional. The treatment of the patient was successfully, and the abnormal cerebral ventricle system gradually recovered during the 12-year follow-up. Because the patient might be probably independent on the shunt, further choice of the shunt removal should be thinking thoroughly, considering both safety and quality of life for the patient.

  17. Extensive intracranial calcification of pseudo-TORCH syndrome with features of Dandy–Walker malformation

    Science.gov (United States)

    Patnaik, Ashis; Mishra, Sudhansu Sekhar; Das, Srikanta

    2017-01-01

    Pseudo-TORCH syndrome or congenital infection-like syndrome is a group of conditions which resemble congenital infections such as those caused by toxoplasmosis, rubella, cytomegalovirus (CMV), herpes (TORCH) group of organisms, clinico-radiologically, but serological tests are negative for the organisms. One of the variety shows features such as microcephaly, extensive intracranial calcification showing gross resemblance to congenital CMV infection, making its other name as microcephaly intracranial calcification syndrome (MICS). Dandy–Walker malformation (DWM), in addition to posterior fossa large cyst, cerebellar vermis hypoplasia, and hydrocephalus is often associated with agenesis of the corpus callosum and callosal lipomas, dysplasia of the brainstem, and cerebellar hypoplasia or dysgenesis. But radiological features of DWM with microcephaly and intracranial calcification are very unusual and have been rarely reported in the literature.[1] We report a case of infant showing clinical features suggestive of congenital CMV infection with negative serology and radiological imaging suggestive of DWM with extensive intracranial calcification. Pseudo-TORCH syndrome with radiological features of DWM is a congenital developmental abnormality. Inspite of hydrocephalus, it does not require cerebrospinal fluid (CSF) diversionary procedure due to lack of increased intracranial pressure. Conservative management for seizure disorder is the optimal therapy. PMID:28761539

  18. Extensive intracranial calcification of pseudo-TORCH syndrome with features of Dandy-Walker malformation.

    Science.gov (United States)

    Patnaik, Ashis; Mishra, Sudhansu Sekhar; Das, Srikanta

    2017-01-01

    Pseudo-TORCH syndrome or congenital infection-like syndrome is a group of conditions which resemble congenital infections such as those caused by toxoplasmosis, rubella, cytomegalovirus (CMV), herpes (TORCH) group of organisms, clinico-radiologically, but serological tests are negative for the organisms. One of the variety shows features such as microcephaly, extensive intracranial calcification showing gross resemblance to congenital CMV infection, making its other name as microcephaly intracranial calcification syndrome (MICS). Dandy-Walker malformation (DWM), in addition to posterior fossa large cyst, cerebellar vermis hypoplasia, and hydrocephalus is often associated with agenesis of the corpus callosum and callosal lipomas, dysplasia of the brainstem, and cerebellar hypoplasia or dysgenesis. But radiological features of DWM with microcephaly and intracranial calcification are very unusual and have been rarely reported in the literature.[1] We report a case of infant showing clinical features suggestive of congenital CMV infection with negative serology and radiological imaging suggestive of DWM with extensive intracranial calcification. Pseudo-TORCH syndrome with radiological features of DWM is a congenital developmental abnormality. Inspite of hydrocephalus, it does not require cerebrospinal fluid (CSF) diversionary procedure due to lack of increased intracranial pressure. Conservative management for seizure disorder is the optimal therapy.

  19. Syringomyelia caused by an arachnoid web in a patient with shunted Dandy-Walker malformation.

    Science.gov (United States)

    Lee, Hee Chang; Choi, Jung Won; Lee, Ji Yeoun; Phi, Ji Hoon; Kim, Seung-Ki; Cho, Byung-Kyu; Wang, Kyu-Chang

    2017-04-01

    Dandy-Walker malformation (DWM) is a congenital brain anomaly characterized by dysgenesis of the cerebellar vermis and the presence of a posterior fossa cyst. The association of syringomyelia with DWM is extremely rare. A 10-year-old patient who was diagnosed with DWM in infancy presented with progressive scoliosis and fecal incontinence. He had been treated with cystoventriculoperitoneal shunting with a Y-connection during infancy, which was followed by a revision 6 years later. During the revision surgery, intraventricular bleeding occurred and was managed conservatively. Imaging studies for the current visit revealed syringomyelia along the cervicothoracic spinal cord and a membranous structure around the cervicomedullary junction. Phase-contrast cine magnetic resonance imaging (MRI) revealed disturbed cerebrospinal fluid (CSF) flow across the membrane. We excised the arachnoid web that was tethering the brainstem and blocking CSF flow. Postoperatively, the patient experienced symptom relief, and the follow-up imaging study demonstrated a dramatic decrease in the size of the syringomyelia. We suggest that syrinx formation in this patient was possibly caused by disturbed CSF flow and tethering of the brainstem. We experienced an unusual case of DWM with syringomyelia which was caused by an arachnoid web blocking CSF flow and tethering the brainstem. The arachnoid web seems to be formed by previous bleeding which occurred at the time of shunt revision. After excision of the arachnoid web, the patient showed good outcome.

  20. Dandy-Walker Variant in A Fetus of an ICSI Twin Gestation: A Case Report

    Directory of Open Access Journals (Sweden)

    Banu Kumbak

    2011-06-01

    Full Text Available Dandy-Walker variant (DWV might be considered as one of the borderlines in the examination of fetal brain. We report the first case of a DWV in a fetus conceived by ICSI. A 34 year-old woman underwent assisted reproductive treatment due to male factor infertility. A twin gestation was achieved, one of the fetuses was diagnosed as DWV on 22 weeks’ ultrasound examination. Fetal MRI confirmed the diagnosis. The couple did not allow fetal karyotyping. Pregnancy continued uneventfully. Associated cardiac and minor skeletal anomalies were seen in the postpartum examination of the affected newborn. She died six days after birth due to pulmonary insufficiency. Karyotype analysis of the affected infant performed after birth was reported to be partial trisomy 9. Parental karyotype analysis was further performed and balanced reciprocal translocation t(4;9 was found in the mother. A careful posterior fossa evaluation should be performed as part of routine anatomical survey in ICSI conceptions. Upon the detection of an anomaly, a comprehensive fetal ultrasound for associated abnormalities and karyotype analysis are vital for obstetric management and neonatal survival.

  1. "Acquired" Dandy-Walker malformation and cerebellar hemorrhage: Usefulness of serial MRI.

    Science.gov (United States)

    Pichiecchio, Anna; Decio, Alice; Di Perri, Carol; Parazzini, Cecilia; Rossi, Andrea; Signorini, Sabrina

    2016-01-01

    Neuroimaging plays a fundamental role in the diagnosis of Dandy Walker malformation (DWM), a posterior fossa anomaly that is usually associated with genetic abnormalities, but may rarely be ascribed to acquired causes. Here, we report the clinical history and neuroimaging studies of a child with a complex cardiac malformation, developmental delay, and oculomotor anomalies whose neuroimaging findings were consistent with an acquired form of DWM. Fetal MRI at gestational weeks 27 and 31 showed cerebellar and vermis hypoplasia and fourth ventricle enlargement, together with hemosiderin deposits on the cerebellar hemispheric surface, but without significant vermian rotation. Postnatal MRIs at 5 days and 13 months revealed progressive counter-clockwise rotation of the hypoplastic cerebellar vermis with cystic dilation of the fourth ventricle, eventually leading to a full-blown DWM. This case strengthens the opinion that DWM is a heterogeneous condition, and may support the hypothesis that acquired meningeal abnormalities in the form of cortico-pial hemosiderosis may play a role in the development of DWM. This case also demonstrates that serial neuroimaging plays a key role in the correct diagnosis of posterior fossa malformations, whose prognosis is difficult to establish on second trimester fetal MRI and requires longer clinical follow-up. Copyright © 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  2. Modelling the effects of the sterile insect technique applied to Eldana saccharina Walker in sugarcane

    Directory of Open Access Journals (Sweden)

    L Potgieter

    2012-12-01

    Full Text Available A mathematical model is formulated for the population dynamics of an Eldana saccharina Walker infestation of sugarcane under the influence of partially sterile released insects. The model describes the population growth of and interaction between normal and sterile E.saccharina moths in a temporally variable, but spatially homogeneous environment. The model consists of a deterministic system of difference equations subject to strictly positive initial data. The primary objective of this model is to determine suitable parameters in terms of which the above population growth and interaction may be quantified and according to which E.saccharina infestation levels and the associated sugarcane damage may be measured. Although many models have been formulated in the past describing the sterile insect technique, few of these models describe the technique for Lepidopteran species with more than one life stage and where F1-sterility is relevant. In addition, none of these models consider the technique when fully sterile females and partially sterile males are being released. The model formulated is also the first to describe the technique applied specifically to E.saccharina, and to consider the economic viability of applying the technique to this species. Pertinent decision support is provided to farm managers in terms of the best timing for releases, release ratios and release frequencies.

  3. Field studies of streamflow generation using natural and injected tracers on Bickford and Walker Branch Watersheds

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, D.; Hemond, H. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Civil Engineering; Mulholland, P. [Oak Ridge National Lab., TN (United States)

    1992-05-01

    Field studies of streamflow generation were undertaken on two forested watersheds, the West Road subcatchment of Bickford Watershed in central Massachusetts and the West Fork of Walker Branch Watershed in eastern Tennessee. A major component of the research was development of a two-stage methodology for the use of naturally-occurring {sup 222}Rn as a tracer. The first of the two stages was solving a mass-balance equation for {sup 222}Rn around a stream reach of interest in order to calculate Rn{sub q}, the {sup 222}Rn content of the lateral inflow to the reach; a conservative tracer (chloride) and a volatile tracer (propane) were injected into the study stream to account for lateral inflow to, and volatilization from, the study reach. The second stage involved quantitative comparison of Rn{sub q} to the measured {sup 222}Rn concentrations of different subsurface waters in order to assess how important these waters were in contributing lateral inflow to the stream reach.

  4. Evolvability as a Quality Attribute of Software Architectures

    NARCIS (Netherlands)

    Ciraci, S.; van den Broek, P.M.; Duchien, Laurence; D'Hondt, Maja; Mens, Tom

    We review the definition of evolvability as it appears on the literature. In particular, the concept of software evolvability is compared with other system quality attributes, such as adaptability, maintainability and modifiability.

  5. Tracking correlated, simultaneously evolving target populations, II

    Science.gov (United States)

    Mahler, Ronald

    2017-05-01

    This paper is the sixth in a series aimed at weakening the independence assumptions that are typically presumed in multitarget tracking. Earlier papers investigated Bayes …lters that propagate the correlations between two evolving multitarget systems. Last year at this conference we attempted to derive PHD …lter-type approximations that account for both spatial correlation and cardinality correlation (i.e., correlation between the target numbers of the two systems). Unfortunately, this approach required heuristic models of both clutter and target appearance in order to incorporate both spatial and cardinality correlation. This paper describes a fully rigorous approach- provided, however, that spatial correlation between the two populations is ignored and only their cardinality correlations are taken into account. We derive the time-update and measurement-update equations for a CPHD …lter describing the evolution of such correlated multitarget populations.

  6. Resiliently evolving supply-demand networks.

    Science.gov (United States)

    Rubido, Nicolás; Grebogi, Celso; Baptista, Murilo S

    2014-01-01

    The ability to design a transport network such that commodities are brought from suppliers to consumers in a steady, optimal, and stable way is of great importance for distribution systems nowadays. In this work, by using the circuit laws of Kirchhoff and Ohm, we provide the exact capacities of the edges that an optimal supply-demand network should have to operate stably under perturbations, i.e., without overloading. The perturbations we consider are the evolution of the connecting topology, the decentralization of hub sources or sinks, and the intermittence of supplier and consumer characteristics. We analyze these conditions and the impact of our results, both on the current United Kingdom power-grid structure and on numerically generated evolving archetypal network topologies.

  7. The Evolving Theory of Evolutionary Radiations.

    Science.gov (United States)

    Simões, M; Breitkreuz, L; Alvarado, M; Baca, S; Cooper, J C; Heins, L; Herzog, K; Lieberman, B S

    2016-01-01

    Evolutionary radiations have intrigued biologists for more than 100 years, and our understanding of the patterns and processes associated with these radiations continues to grow and evolve. Recently it has been recognized that there are many different types of evolutionary radiation beyond the well-studied adaptive radiations. We focus here on multifarious types of evolutionary radiations, paying special attention to the abiotic factors that might trigger diversification in clades. We integrate concepts such as exaptation, species selection, coevolution, and the turnover-pulse hypothesis (TPH) into the theoretical framework of evolutionary radiations. We also discuss other phenomena that are related to, but distinct from, evolutionary radiations that have relevance for evolutionary biology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Epidemic spreading on evolving signed networks

    CERN Document Server

    Saeedian, M; Jafari, G R; Kertesz, J

    2016-01-01

    Most studies of disease spreading consider the underlying social network as obtained without the contagion, though epidemic influences peoples willingness to contact others: A friendly contact may be turned to unfriendly to avoid infection. We study the susceptible-infected (SI) disease spreading model on signed networks, in which each edge is associated with a positive or negative sign representing the friendly or unfriendly relation between its end nodes. In a signed network, according to Heiders theory, edge signs evolve such that finally a state of structural balance is achieved, corresponding to no frustration in physics terms. However, the danger of infection affects the evolution of its edge signs. To describe the coupled problem of the sign evolution and disease spreading, we generalize the notion of structural balance by taking into account the state of the nodes. We introduce an energy function and carry out Monte-Carlo simulations on complete networks to test the energy landscape, where we find loc...

  9. Finch: A System for Evolving Java (Bytecode)

    Science.gov (United States)

    Orlov, Michael; Sipper, Moshe

    The established approach in genetic programming (GP) involves the definition of functions and terminals appropriate to the problem at hand, after which evolution of expressions using these definitions takes place. We have recently developed a system, dubbed FINCH (Fertile Darwinian Bytecode Harvester), to evolutionarily improve actual, extant software, which was not intentionally written for the purpose of serving as a GP representation in particular, nor for evolution in general. This is in contrast to existing work that uses restricted subsets of the Java bytecode instruction set as a representation language for individuals in genetic programming. The ability to evolve Java programs will hopefully lead to a valuable new tool in the software engineer's toolkit.

  10. Bioactivity-guided isolation of antiplasmodial constituents from Conyza sumatrensis (Retz.) E.H. Walker.

    Science.gov (United States)

    Boniface, Pone Kamdem; Verma, Surjeet; Shukla, Aparna; Cheema, Harveer Singh; Srivastava, Santosh Kumar; Khan, Feroz; Darokar, Mahendra Pandurang; Pal, Anirban

    2015-02-01

    Conyza sumatrensis (Retz.) E.H. Walker (Cs) leaves are used for traditional treatment of malaria in Cameroon. However, the antimalarial activity of the leaf constituents of this plant is still unexplored. The aim of our investigation was to evaluate the antiplasmodial activity of some bioactive constituents from Cs leaves. Compounds were isolated from Cs leaves and structurally elucidated using extensive spectroscopic analysis. The in vitro antiplasmodial activity of the extracts and pure compounds were evaluated on chloroquine-sensitive strain (NF54) of Plasmodium falciparum. The in vivo assay was done by administering seven doses of extracts in mice infected with Plasmodium berghei K173 through oral route. Cytotoxicity of pure compounds on murine macrophage cells was performed through [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] (MTT) test. Hemolysis and lactate dehydrogenase assays were also carried out using standard procedures. The in silico prediction of bioactive constituents was performed through Autodock Vina. Polarity-based extracts from Cs were found to be active against P. falciparum (NF54) and P. berghei (K173) in vitro and in vivo respectively. Further, bioactivity-guided isolation of n-hexane fraction yielded three compounds, (1), (2) and (3) with IC50 of 34, 17.9 and 18μg/ml, respectively, while the ethyl acetate fraction afforded the fourth compound with an IC50 of 25μg/ml, indicating anti-malarial potential of Cs through PfLDH interaction without compromising normal cell growth. This study reports for the first time, the antiplasmodial activity of bioactive constituents from Cs and confirms its traditional use. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Casimir effect for parallel plates in a Friedmann-Robertson-Walker universe

    Science.gov (United States)

    Bezerra de Mello, E. R.; Saharian, A. A.; Setare, M. R.

    2017-03-01

    We evaluate the Hadamard function, the vacuum expectation values (VEVs) of the field squared and the energy-momentum tensor for a massive scalar field with a general curvature coupling parameter in the geometry of two parallel plates on a spatially flat Friedmann-Robertson-Walker background with a general scale factor. On the plates, the field operator obeys the Robin boundary conditions with the coefficients depending on the scale factor. In all the spatial regions, the VEVs are decomposed into the boundary-free and boundary-induced contributions. Unlike the problem with the Minkowski bulk, in the region between the plates, the normal stress is not homogeneous and does not vanish in the geometry of a single plate. Near the plates, it has different signs for accelerated and decelerated expansions of the Universe. The VEV of the energy-momentum tensor, in addition to the diagonal components, has a nonzero off-diagonal component describing an energy flux along the direction normal to the boundaries. Expressions are derived for the Casimir forces acting on the plates. Depending on the Robin coefficients and on the vacuum state, these forces can be either attractive or repulsive. An important difference from the corresponding result in the Minkowski bulk is that the forces on the separate plates, in general, are different if the corresponding Robin coefficients differ. We give the applications of general results for the class of α vacua in the de Sitter bulk. It is shown that, compared with the Bunch-Davies vacuum state, the Casimir forces for a given α vacuum may change the sign.

  12. Experimental in vivo measurements of light emission in plants: a perspective dedicated to David Walker.

    Science.gov (United States)

    Kalaji, Hazem M; Goltsev, Vasilij; Bosa, Karolina; Allakhverdiev, Suleyman I; Strasser, Reto J; Govindjee

    2012-12-01

    This review is dedicated to David Walker (1928-2012), a pioneer in the field of photosynthesis and chlorophyll fluorescence. We begin this review by presenting the history of light emission studies, from the ancient times. Light emission from plants is of several kinds: prompt fluorescence (PF), delayed fluorescence (DF), thermoluminescence, and phosphorescence. In this article, we focus on PF and DF. Chlorophyll a fluorescence measurements have been used for more than 80 years to study photosynthesis, particularly photosystem II (PSII) since 1961. This technique has become a regular trusted probe in agricultural and biological research. Many measured and calculated parameters are good biomarkers or indicators of plant tolerance to different abiotic and biotic stressors. This would never have been possible without the rapid development of new fluorometers. To date, most of these instruments are based mainly on two different operational principles for measuring variable chlorophyll a fluorescence: (1) a PF signal produced following a pulse-amplitude-modulated excitation and (2) a PF signal emitted during a strong continuous actinic excitation. In addition to fluorometers, other instruments have been developed to measure additional signals, such as DF, originating from PSII, and light-induced absorbance changes due to the photooxidation of P700, from PSI, measured as the absorption decrease (photobleaching) at about 705 nm, or increase at 820 nm. In this review, the technical and theoretical basis of newly developed instruments, allowing for simultaneous measurement of the PF and the DF as well as other parameters is discussed. Special emphasis has been given to a description of comparative measurements on PF and DF. However, DF has been discussed in greater details, since it is much less used and less known than PF, but has a great potential to provide useful qualitative new information on the back reactions of PSII electron transfer. A review concerning the history

  13. Increased thermal response to ultrasound in the Walker carcinosarcoma treated with vasoactive drugs

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, W.H.; Debatin, J.; Helus, F.; Sinn, H.J.; Ostertag, H.

    1989-04-01

    In order to evaluate the potential of a highly selective Ca2+ entry blocker (nisoldipine) and of 5-hydroxytryptamine (5-HT) as adjuvant in hyperthermia treatment, we studied the differential flow response and time-course of tumor and normal tissue temperature following the administration of the two substances and during ultrasound heating. In 12 rats bearing Walker 256 carcinomas i.p. injection of 0.2-0.4 mg/kg nisoldipine caused a reduction in the tumor-to-muscle flow relationship of 4.4 +/- 1.9 (SD) to 1.74 +/- 0.86 as determined by intraarterial 133Xe injection; i.p. injection of 2-8 mg/kg 5-HT (N = 13) caused a respective reduction from 3.9 +/- 2.67 to 1.3 +/- 1.59. During a 20-min period of 41 degrees C normal tissue temperature-controlled ultrasound heating without drugs, tumor temperature attained 40.8 +/- 0.9 degrees C (N = 16). Nisoldipine or 5-HT injection at continuing 41 degrees C normal tissue temperature controlled energy delivery produced an instantaneous further increment of tumor temperature, eventually to 44.0 +/- 1.14 degrees C or 44.2 +/- 1.26 degrees C, respectively, after a period of 20 min. Injection of 0.9% NaCl (N = 4) solution caused only insignificant changes. Blood pressure and muscle perfusion were distinctly influenced by nisoldipine, but not by 5-HT. Since both drugs instantaneously increased the temperature differential between tumor and normal tissue, though by different vasoaction, they should be considered as adjuvants in hyperthermia.

  14. Instrumented gait analysis: a measure of gait improvement by a wheeled walker in hospitalized geriatric patients.

    Science.gov (United States)

    Schülein, Samuel; Barth, Jens; Rampp, Alexander; Rupprecht, Roland; Eskofier, Björn M; Winkler, Jürgen; Gaßmann, Karl-Günter; Klucken, Jochen

    2017-02-27

    In an increasing aging society, reduced mobility is one of the most important factors limiting activities of daily living and overall quality of life. The ability to walk independently contributes to the mobility, but is increasingly restricted by numerous diseases that impair gait and balance. The aim of this cross-sectional observation study was to examine whether spatio-temporal gait parameters derived from mobile instrumented gait analysis can be used to measure the gait stabilizing effects of a wheeled walker (WW) and whether these gait parameters may serve as surrogate marker in hospitalized patients with multifactorial gait and balance impairment. One hundred six patients (ages 68-95) wearing inertial sensor equipped shoes passed an instrumented walkway with and without gait support from a WW. The walkway assessed the risk of falling associated gait parameters velocity, swing time, stride length, stride time- and double support time variability. Inertial sensor-equipped shoes measured heel strike and toe off angles, and foot clearance. The use of a WW improved the risk of spatio-temporal parameters velocity, swing time, stride length and the sagittal plane associated parameters heel strike and toe off angles in all patients. First-time users (FTUs) showed similar gait parameter improvement patterns as frequent WW users (FUs). However, FUs with higher levels of gait impairment improved more in velocity, stride length and toe off angle compared to the FTUs. The impact of a WW can be quantified objectively by instrumented gait assessment. Thus, objective gait parameters may serve as surrogate markers for the use of walking aids in patients with gait and balance impairments.

  15. Cystic lesion of posterior cranial fossa: is it Dandy-Walker?

    Directory of Open Access Journals (Sweden)

    Stella De Nardi

    2017-11-01

    Full Text Available Accidental discovery of a fluid collection within the posterior cranial fossa in a fetus or a newborn can be a tricky incidental finding during a routine scan, alarming for a Dandy-Walker Malformation (DWM.The main cystic lesions of the posterior cranial fossa are DWM, Blake’s Pouch Cyst (BPC, Arachnoid Cyst (AC and Mega Cisterna Magna (MCM, although the latter is not a proper cyst. The key event for the development of a DWM is a cerebellar vermis hypoplasia that causes the persistence of the superior membranous area, which expands into the posterior fossa forming a large cystic 4th ventricle. BPC is caused by the persistence and herniation of a different membrane, the inferior membranous area, that is supposed to disappear leaving a median opening that would become the foramen of Magendie. MCM originates if this membrane eventually disappears, leaving an enlarged posterior fossa cavity filled with cerebrospinal fluid physiologically connected with the subarachnoid fluid. Finally, ACs are caused by a defined duplication of the arachnoid membrane filled with CSF-like fluid. Consequently, the radiological finding of a regular cerebellar vermis excludes the hypothesis of DWM and the position of the choroid plexus helps differentiating between DWM and BPC in controversial cases. Moreover, radiological findings in DWM include cystic dilatation of the 4th ventricle and enlargement of the posterior fossa. Absence of hydrocephalus comes out in favor of MCM. Absence of communication with surrounding cerebrospinal fluid defines an AC.This review assesses the cystic lesions of posterior cranial fossa on the basis of embryological development, radiological findings and associated clinical aspects, in order to clarify the radiological differential diagnosis through embryology.

  16. Risk factors for Dandy-Walker malformation: a population-based assessment.

    Science.gov (United States)

    Reeder, Matthew R; Botto, Lorenzo D; Keppler-Noreuil, Kim M; Carey, John C; Byrne, Janice L B; Feldkamp, Marcia L

    2015-09-01

    Dandy-Walker malformation (DWM) is the most common congenital malformation of the cerebellum, but its causes are largely unknown. An increasing number of genes associated with congenital cerebellar malformations have been identified; however, few studies have examined the potential role of non-genetic, potentially modifiable risk factors. From the National Birth Defects Prevention Study, we examined maternal, paternal, and infant characteristics and maternal conditions and periconceptional exposures (from 1 month before to 3 months after conception) among infants with DWM (n = 160) and unaffected controls (n = 10,200), delivered between 1997 and 2009. Odds ratios, crude (cOR) and adjusted (aOR) were computed using logistic regression. Maternal factors associated with DWM included non-Hispanic black race/ethnicity (aOR = 2.0, 95%CI: 1.3-3.2). Among maternal conditions, a history of infertility increased the risk for DWM (all: aOR = 2.4, 95%CI: 1.3-4.6; multiple: aOR = 3.9, 95%CI: 1.7-8.9). The lack of association with many maternal exposures supports the hypothesis of a major contribution of genetic factors to the risk for DWM; however, the observed associations with maternal non-Hispanic black race/ethnicity and maternal history of infertility indicate that further research into factors underlying these characteristics may uncover potentially modifiable risk factors, acting alone or as a component of gene-environment interactions. © 2015 Wiley Periodicals, Inc.

  17. Prenatal diagnosis of 'isolated' Dandy-Walker malformation: imaging findings and prenatal counselling.

    Science.gov (United States)

    Guibaud, Laurent; Larroque, Anne; Ville, Dorothée; Sanlaville, Damien; Till, Marianne; Gaucherand, Pascal; Pracros, Jean-Pierre; des Portes, Vincent

    2012-02-01

    The purpose of this article is to improve prenatal imaging diagnosis and counselling for cases of 'isolated' Dandy-Walker malformation (DWM) in the light of recent literature, which has demonstrated a potential good clinical and intellectual outcome of fetuses presenting with DWM characterised by partial vermian agenesis (identification of two fissures and three lobes) and absence of associated anatomical anomalies. This is a retrospective observational study of six consecutive prenatal cystic posterior fossa malformations, diagnosed as DWM, encountered in a national reference centre for posterior fossa malformations over a 2-year period. In all cases, DWM was diagnosed as isolated (without any associated central nervous system or extra-central nervous system malformations and normal standard karyotype). Despite good-quality imaging, including fetal magnetic resonance imaging (MRI), prenatal analysis of the vermis was impossible because of limited identification of fissuration and lobulation. In three cases, a cytogenetic anomaly was found, including 6p subtelomeric deletion (n = 2) and partial 4 qter deletion associated with partial 7p trisomy (n = 1). One fetus with 6p deletion was terminated. In four of the five postnatal cases, MRI confirmed the diagnosis of DWM but provided only limited information for vermian analysis. In one case, postnatal MRI showed a large Blake's pouch cyst with rotated but complete vermis associated with a marked mass effect on the distal part of the tentorium. Of the four babies born with postnatal diagnosis of DWM, all required ventriculoperitoneal shunting because of early postnatal hydrocephalus. When fetal MRI is necessary to exclude additional cerebral lesions in the diagnosis of DWM, we highlight the inaccuracy of magnetic resonance for anatomical analysis of the vermis. We also emphasise the potential high incidence of subtelomeric anomalies in isolated DWM, especially 6p deletion. In the postnatal period, paediatricians should

  18. Changes in cellular immune responses of Chilo suppressalis Walker (Lepidoptera: Crambidae due to pyriproxyfen treatment

    Directory of Open Access Journals (Sweden)

    Mirhaghparast Seyyedeh Kimia

    2015-07-01

    Full Text Available The effects of pyriproxyfen were determined on the cellular immunity and phenoloxidase activity in the 4th instar larvae of Chilo suppressalis Walker. The bioassay results revealed the effective concentrations of: 10L : 18C, 30L : 72C and 50L : 190C μg · ml−1. The sole effect of 18 and 72 μg · ml−1 concentrations at intervals of 1–3 h caused a higher number of total hemocytes in the treated larvae than the control, but the reverse results were observed after 6–24 h. The number of plasmatocytes was lower than that of the control for intervals of 3–24 h but the number of granulocytes was higher than the control after 1–3 h although no significant differences were observed at the other times. In the treated larvae, the activities of phenoloxidase were higher and lower than those of the control after 1–3 h and 6–24 h, respectively. The combined effects of pyriproxyfen and the entomopathogenic fungus, Beauveria bassiana isolate B3 caused higher numbers of total hemocytes, plasmatocytes, and granulocytes in the treated larvae by use of the three concentrations of pyriproxyfen, at intervals of 6 and 12 h. Although the numbers of nodules in the larvae treated with concentrations of 18 μg · ml−1 were higher than those of other treatments, the overall numbers were lower than those of the control. Finally, the activity of phenoloxidase in the treated larvae was higher than that of the control, at intervals of 6 and 12 h post-treatment. Findings of the current study indicate an intervening role of pyriproxyfen in the cellular immunity of C. suppressalis to entomopathogenic objects.

  19. Population genetics of Eldana saccharina Walker (Lepidoptera: Pyralidae) and the implications for management using biocontrol.

    Science.gov (United States)

    Assefa, Y; Mitchell, A; Le Rü, B P; Conlongs, D E

    2010-01-01

    The African sugarcane stalk borer, Eldona saccharina Walker (Lepidoptera: Pyralidae), is widely distributed throughout sub-Saharan Africa and is an important insect pest of maize and sugarcane. The insect shows significant variation in behaviour, host plant and natural enemy guild in different regions. Several attempts to redistribute the natural enemies of E. saccharina from West Africa to South Africa were unsuccessful. The significant behavioural, host plant and natural enemy variations as well as failures of biocontrol attempts evoked a hypothesis of genetic diversification. To evaluate this hypothesis a molecular analysis was conducted on geographically isolated populations of E. saccharina from East, North, South and West Africa, using the cytochrome c oxidase subunit I (COI) region of the mitochondrial genome. The results revealed that E. saccharina populations are separated into four major units corresponding to the West Africa, Rift Valley, South/East Africa and southern African populations. Mitochondrial DNA divergence among the four populations ranged from 1% to 4.98%. To examine the impact of the observed genetic variation on the fertility of inter-population crosses, a mating experiment was conducted between the Rift valley and South African population to produce an F1 generation, and these were backcrossed with the South African parent population. Fertility of eggs produced by the F1/parent population cross was significantly reduced when compared to fertility of the "true" South African line, and the F1/F1 cross. The contributions of the observed genetic differences and inter population incompatibility for the failure of previous biocontrol attempts are discussed and recommendations on future biocontrol practices are given.

  20. Síndrome de Dandy-Walker: a propósito de 4 casos

    Directory of Open Access Journals (Sweden)

    Gilberto Machado de Almeida

    1960-09-01

    Full Text Available Dá-se o nome de síndrome de Dandy-Walker a um tipo de hidrocefalia cuja principal característica é a transformação do IV ventrículo em um grande cisto, que ocupa quase tôda a fossa posterior; esta, por sua vez, está aumentada, devido à elevação da tenda do cerebelo e abaulamento do occipital. A patogenia do processo é discutida; admite-se geralmente que se trate de um vício de desenvolvimento determinado pela falta de abertura dos orifícios de Luschka e Magendie. Em revisão bibliográfica foram encontrados 60 casos. São apresentados mais 4, dois dos quais foram submetidos à derivação ventrículo-jugular pela técnica de Spitz-Holter. São discutidos os principais sinais clínicos, os exames subsidiários e a terapêutica. A posição anormalmente alta dos seios transversos, observada no craniograma ou na sinugrafia, é considerada como sinal patognomônico. A transiluminação do crânio também pode apresentar aspecto característico. Êstes exames, quando típicos, permitem evitar a realização de exames mais traumatizantes, como as ventriculografias. A terapêutica mais empregada tem sido a abertura da parede do cisto. Não há na literatura referência à operação de Spitz que, em nossa opinião, é a melhor forma de tratamento.

  1. Randomization tests

    CERN Document Server

    Edgington, Eugene

    2007-01-01

    Statistical Tests That Do Not Require Random Sampling Randomization Tests Numerical Examples Randomization Tests and Nonrandom Samples The Prevalence of Nonrandom Samples in Experiments The Irrelevance of Random Samples for the Typical Experiment Generalizing from Nonrandom Samples Intelligibility Respect for the Validity of Randomization Tests Versatility Practicality Precursors of Randomization Tests Other Applications of Permutation Tests Questions and Exercises Notes References Randomized Experiments Unique Benefits of Experiments Experimentation without Mani

  2. Quantifying seepage using heat as a tracer in selected irrigation canals, Walker River Basin, Nevada, 2012 and 2013

    Science.gov (United States)

    Naranjo, Ramon C.; Smith, David W.

    2016-11-16

    The Walker River is an important source of water for western Nevada. The river provides water for agriculture and recharge to local aquifers used by several communities. Farmers began diverting water from the Walker River in the 1860s to support growing agricultural development. Over time, the reduced inflows into Walker Lake from upstream reservoirs and diversions have resulted in 170 feet of lake level decline and increased dissolved-solids concentrations to levels that threaten aquatic ecosystems, including survival of Lahonton cutthroat trout, a native species listed in the Endangered Species Act. Investigations of the water-budget components in the Walker River Basin have revealed uncertainty in the recharge to aquifers from irrigation canals. To address this need, the U.S. Geological Survey conducted an extensive field study from March 2012 through October 2013 to quantify seepage losses in selected canals in the Smith Valley, Mason Valley, and Walker Lake Valley irrigation areas.The seepage rates estimated for the 2012 and 2013 irrigation seasons in the Smith Valley transect sites (Saroni and Plymouth canals) ranged between 0.01 to 2.5 feet per day (ft/d) (0.01 to 0.68 cubic feet per second per mile [ft3/s-mi]). From 2012 to 2013, the average number of days the canals had flowing water decreased from 190 to 125 due to drier climate and lack of water available for diversion from the Walker River. The nearly 50-percent reductions in volumetric loss rates between 2012 and 2013 were associated with less than average diversions into canals from the Walker River and reductions in infiltration rates following routine canal maintenance.Models developed for the Saroni canal in 2012 were recalibrated in 2013 to evaluate changes in seepage as a result of siltation. Just prior to the 2012 irrigation season, nearly the entire length of the canal was cleared of vegetation and debris to improve flow conveyance. In 2013, following the first year of maintenance, a 90-percent

  3. The evolving energy budget of accretionary wedges

    Science.gov (United States)

    McBeck, Jessica; Cooke, Michele; Maillot, Bertrand; Souloumiac, Pauline

    2017-04-01

    The energy budget of evolving accretionary systems reveals how deformational processes partition energy as faults slip, topography uplifts, and layer-parallel shortening produces distributed off-fault deformation. The energy budget provides a quantitative framework for evaluating the energetic contribution or consumption of diverse deformation mechanisms. We investigate energy partitioning in evolving accretionary prisms by synthesizing data from physical sand accretion experiments and numerical accretion simulations. We incorporate incremental strain fields and cumulative force measurements from two suites of experiments to design numerical simulations that represent accretionary wedges with stronger and weaker detachment faults. One suite of the physical experiments includes a basal glass bead layer and the other does not. Two physical experiments within each suite implement different boundary conditions (stable base versus moving base configuration). Synthesizing observations from the differing base configurations reduces the influence of sidewall friction because the force vector produced by sidewall friction points in opposite directions depending on whether the base is fixed or moving. With the numerical simulations, we calculate the energy budget at two stages of accretion: at the maximum force preceding the development of the first thrust pair, and at the minimum force following the development of the pair. To identify the appropriate combination of material and fault properties to apply in the simulations, we systematically vary the Young's modulus and the fault static and dynamic friction coefficients in numerical accretion simulations, and identify the set of parameters that minimizes the misfit between the normal force measured on the physical backwall and the numerically simulated force. Following this derivation of the appropriate material and fault properties, we calculate the components of the work budget in the numerical simulations and in the

  4. Experimental inoculation model of Walker 256 carcinoma into vagina and cervix uteri of female rats Modelo experimental de Tumor de Walker 256 em vagina e colo de útero de ratas

    Directory of Open Access Journals (Sweden)

    Nara Macedo Botelho Brito

    2007-12-01

    Full Text Available PURPOSE: To establish an inoculation model of Walker 256 carcinoma on cervix uteri and vagina of rats. METHODS: Fifteen female rats were used, and assigned to three groups each one with five rats: group A - rats with 4x10(6 cells of Walker 256 carcinoma without acid acetic inoculation; group B - rats with 2x10(6 cells of Walker 256 carcinoma with acid acetic inoculation and group C: rats with 4x10(6 cells of Walker 256 carcinoma with acid acetic inoculation. The day before tumor cells inoculation the rats from groups B and C were anaesthetized with diethylether and 0,3 ml of acetic acid was inoculated into their vaginas. Tumor cell inoculation into the vagina and cervix was done under general anesthesia with diethylether. Then a endocervical brush was used to scrape the vaginal wall and after that 0,3 ml of the liquid containing tumor cells was inoculated on the vagina and cervix. For the tumor analysis, animals were euthanized at day 12 following tumor cell implantation by an excessive inhalation of diethylether. Tumor was resected entirely and weighed and the tumors were then sectioned and counter stained with hematoxylin and eosin for histopathologic evaluation. It was also calculated the percentage of tumor equivalent to the body weight by the formula: P= tumor weight / body weight x 100. Data were analyzed by one-way analysis of variance - ANOVA. P values OBJETIVO: Estabelecer um modelo de inoculação de Tumor de Walker 256 em vagina e colo de útero de ratas. MÉTODOS: Foram utilizadas 15 ratas fêmeas, virgens, adultas, pesando entre 200-250g, distribuídas em três grupos de estudo com cinco animais cada: grupo A (GA: ratas com tumor de Walker 256 em concentração de 4x10(6 sem ácido acético; grupo B (GB: ratas com tumor de Walker 256 em concentração de 2x10(6 células com ácido acético; grupo C (GC: ratas com tumor de Walker 256 em concentração de 4x10(6 células com ácido acético. No dia anterior à inoculação do tumor

  5. On the Critical Role of Divergent Selection in Evolvability

    Directory of Open Access Journals (Sweden)

    Joel Lehman

    2016-08-01

    Full Text Available An ambitious goal in evolutionary robotics is to evolve increasingly complex robotic behaviors with minimal human design effort. Reaching this goal requires evolutionary algorithms that can unlock from genetic encodings their latent potential for evolvability. One issue clouding this goal is conceptual confusion about evolvability, which often obscures the aspects of evolvability that are important or desirable. The danger from such confusion is that it may establish unrealistic goals for evolvability that prove unproductive in practice. An important issue separate from conceptual confusion is the common misalignment between selection and evolvability in evolutionary robotics. While more expressive encodings can represent higher-level adaptations (e.g. sexual reproduction or developmental systems that increase long-term evolutionary potential (i.e. evolvability, realizing such potential requires gradients of fitness and evolvability to align. In other words, selection is often a critical factor limiting increasing evolvability. Thus, drawing from a series of recent papers, this article seeks to both (1 clarify and focus the ways in which the term evolvability is used within artificial evolution, and (2 argue for the importance of one type of selection, i.e. divergent selection, for enabling evolvability. The main argument is that there is a fundamental connection between divergent selection and evolvability (on both the individual and population level that does not hold for typical goal-oriented selection. The conclusion is that selection pressure plays a critical role in realizing the potential for evolvability, and that divergent selection in particular provides a principled mechanism for encouraging evolvability in artificial evolution.

  6. How does cognition evolve? Phylogenetic comparative psychology

    Science.gov (United States)

    Matthews, Luke J.; Hare, Brian A.; Nunn, Charles L.; Anderson, Rindy C.; Aureli, Filippo; Brannon, Elizabeth M.; Call, Josep; Drea, Christine M.; Emery, Nathan J.; Haun, Daniel B. M.; Herrmann, Esther; Jacobs, Lucia F.; Platt, Michael L.; Rosati, Alexandra G.; Sandel, Aaron A.; Schroepfer, Kara K.; Seed, Amanda M.; Tan, Jingzhi; van Schaik, Carel P.; Wobber, Victoria

    2014-01-01

    Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution. PMID:21927850

  7. Approximating centrality in evolving graphs: toward sublinearity

    Science.gov (United States)

    Priest, Benjamin W.; Cybenko, George

    2017-05-01

    The identification of important nodes is a ubiquitous problem in the analysis of social networks. Centrality indices (such as degree centrality, closeness centrality, betweenness centrality, PageRank, and others) are used across many domains to accomplish this task. However, the computation of such indices is expensive on large graphs. Moreover, evolving graphs are becoming increasingly important in many applications. It is therefore desirable to develop on-line algorithms that can approximate centrality measures using memory sublinear in the size of the graph. We discuss the challenges facing the semi-streaming computation of many centrality indices. In particular, we apply recent advances in the streaming and sketching literature to provide a preliminary streaming approximation algorithm for degree centrality utilizing CountSketch and a multi-pass semi-streaming approximation algorithm for closeness centrality leveraging a spanner obtained through iteratively sketching the vertex-edge adjacency matrix. We also discuss possible ways forward for approximating betweenness centrality, as well as spectral measures of centrality. We provide a preliminary result using sketched low-rank approximations to approximate the output of the HITS algorithm.

  8. How does cognition evolve? Phylogenetic comparative psychology.

    Science.gov (United States)

    MacLean, Evan L; Matthews, Luke J; Hare, Brian A; Nunn, Charles L; Anderson, Rindy C; Aureli, Filippo; Brannon, Elizabeth M; Call, Josep; Drea, Christine M; Emery, Nathan J; Haun, Daniel B M; Herrmann, Esther; Jacobs, Lucia F; Platt, Michael L; Rosati, Alexandra G; Sandel, Aaron A; Schroepfer, Kara K; Seed, Amanda M; Tan, Jingzhi; van Schaik, Carel P; Wobber, Victoria

    2012-03-01

    Now more than ever animal studies have the potential to test hypotheses regarding how cognition evolves. Comparative psychologists have developed new techniques to probe the cognitive mechanisms underlying animal behavior, and they have become increasingly skillful at adapting methodologies to test multiple species. Meanwhile, evolutionary biologists have generated quantitative approaches to investigate the phylogenetic distribution and function of phenotypic traits, including cognition. In particular, phylogenetic methods can quantitatively (1) test whether specific cognitive abilities are correlated with life history (e.g., lifespan), morphology (e.g., brain size), or socio-ecological variables (e.g., social system), (2) measure how strongly phylogenetic relatedness predicts the distribution of cognitive skills across species, and (3) estimate the ancestral state of a given cognitive trait using measures of cognitive performance from extant species. Phylogenetic methods can also be used to guide the selection of species comparisons that offer the strongest tests of a priori predictions of cognitive evolutionary hypotheses (i.e., phylogenetic targeting). Here, we explain how an integration of comparative psychology and evolutionary biology will answer a host of questions regarding the phylogenetic distribution and history of cognitive traits, as well as the evolutionary processes that drove their evolution.

  9. On the Discovery of Evolving Truth.

    Science.gov (United States)

    Li, Yaliang; Li, Qi; Gao, Jing; Su, Lu; Zhao, Bo; Fan, Wei; Han, Jiawei

    2015-08-01

    In the era of big data, information regarding the same objects can be collected from increasingly more sources. Unfortunately, there usually exist conflicts among the information coming from different sources. To tackle this challenge, truth discovery, i.e., to integrate multi-source noisy information by estimating the reliability of each source, has emerged as a hot topic. In many real world applications, however, the information may come sequentially, and as a consequence, the truth of objects as well as the reliability of sources may be dynamically evolving. Existing truth discovery methods, unfortunately, cannot handle such scenarios. To address this problem, we investigate the temporal relations among both object truths and source reliability, and propose an incremental truth discovery framework that can dynamically update object truths and source weights upon the arrival of new data. Theoretical analysis is provided to show that the proposed method is guaranteed to converge at a fast rate. The experiments on three real world applications and a set of synthetic data demonstrate the advantages of the proposed method over state-of-the-art truth discovery methods.

  10. Sexual regret: evidence for evolved sex differences.

    Science.gov (United States)

    Galperin, Andrew; Haselton, Martie G; Frederick, David A; Poore, Joshua; von Hippel, William; Buss, David M; Gonzaga, Gian C

    2013-10-01

    Regret and anticipated regret enhance decision quality by helping people avoid making and repeating mistakes. Some of people's most intense regrets concern sexual decisions. We hypothesized evolved sex differences in women's and men's experiences of sexual regret. Because of women's higher obligatory costs of reproduction throughout evolutionary history, we hypothesized that sexual actions, particularly those involving casual sex, would be regretted more intensely by women than by men. In contrast, because missed sexual opportunities historically carried higher reproductive fitness costs for men than for women, we hypothesized that poorly chosen sexual inactions would be regretted more by men than by women. Across three studies (Ns = 200, 395, and 24,230), we tested these hypotheses using free responses, written scenarios, detailed checklists, and Internet sampling to achieve participant diversity, including diversity in sexual orientation. Across all data sources, results supported predicted psychological sex differences and these differences were localized in casual sex contexts. These findings are consistent with the notion that the psychology of sexual regret was shaped by recurrent sex differences in selection pressures operating over deep time.

  11. Extracting evolving pathologies via spectral clustering.

    Science.gov (United States)

    Bernardis, Elena; Pohl, Kilian M; Davatzikos, Christos

    2013-01-01

    A bottleneck in the analysis of longitudinal MR scans with white matter brain lesions is the temporally consistent segmentation of the pathology. We identify pathologies in 3D+t(ime) within a spectral graph clustering framework. Our clustering approach simultaneously segments and tracks the evolving lesions by identifying characteristic image patterns at each time-point and voxel correspondences across time-points. For each 3D image, our method constructs a graph where weights between nodes capture the likeliness of two voxels belonging to the same region. Based on these weights, we then establish rough correspondences between graph nodes at different time-points along estimated pathology evolution directions. We combine the graphs by aligning the weights to a reference time-point, thus integrating temporal information across the 3D images, and formulate the 3D+t segmentation problem as a binary partitioning of this graph. The resulting segmentation is very robust to local intensity fluctuations and yields better results than segmentations generated for each time-point.

  12. Functional Topology of Evolving Urban Drainage Networks

    Science.gov (United States)

    Yang, Soohyun; Paik, Kyungrock; McGrath, Gavan S.; Urich, Christian; Krueger, Elisabeth; Kumar, Praveen; Rao, P. Suresh C.

    2017-11-01

    We investigated the scaling and topology of engineered urban drainage networks (UDNs) in two cities, and further examined UDN evolution over decades. UDN scaling was analyzed using two power law scaling characteristics widely employed for river networks: (1) Hack's law of length (L)-area (A) [L∝Ah] and (2) exceedance probability distribution of upstream contributing area (δ) [P>(A≥δ>)˜aδ-ɛ]. For the smallest UDNs ((A≥δ>) plots for river networks are abruptly truncated, those for UDNs display exponential tempering [P>(A≥δ>)=aδ-ɛexp⁡>(-cδ>)]. The tempering parameter c decreases as the UDNs grow, implying that the distribution evolves in time to resemble those for river networks. However, the power law exponent ɛ for large UDNs tends to be greater than the range reported for river networks. Differences in generative processes and engineering design constraints contribute to observed differences in the evolution of UDNs and river networks, including subnet heterogeneity and nonrandom branching.

  13. The Evolving Classification of Pulmonary Hypertension.

    Science.gov (United States)

    Foshat, Michelle; Boroumand, Nahal

    2017-05-01

    - An explosion of information on pulmonary hypertension has occurred during the past few decades. The perception of this disease has shifted from purely clinical to incorporate new knowledge of the underlying pathology. This transfer has occurred in light of advancements in pathophysiology, histology, and molecular medical diagnostics. - To update readers about the evolving understanding of the etiology and pathogenesis of pulmonary hypertension and to demonstrate how pathology has shaped the current classification. - Information presented at the 5 World Symposia on pulmonary hypertension held since 1973, with the last meeting occurring in 2013, was used in this review. - Pulmonary hypertension represents a heterogeneous group of disorders that are differentiated based on differences in clinical, hemodynamic, and histopathologic features. Early concepts of pulmonary hypertension were largely influenced by pharmacotherapy, hemodynamic function, and clinical presentation of the disease. The initial nomenclature for pulmonary hypertension segregated the clinical classifications from pathologic subtypes. Major restructuring of this disease classification occurred between the first and second symposia, which was the first to unite clinical and pathologic information in the categorization scheme. Additional changes were introduced in subsequent meetings, particularly between the third and fourth World Symposia meetings, when additional pathophysiologic information was gained. Discoveries in molecular diagnostics significantly progressed the understanding of idiopathic pulmonary arterial hypertension. Continued advancements in imaging modalities, mechanistic pathogenicity, and molecular biomarkers will enable physicians to define pulmonary hypertension phenotypes based on the pathobiology and allow for treatment customization.

  14. Evolving application of biomimetic nanostructured hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Norberto Roveri

    2010-11-01

    Full Text Available Norberto Roveri, Michele IafiscoLaboratory of Environmental and Biological Structural Chemistry (LEBSC, Dipartimento di Chimica ‘G. Ciamician’, Alma Mater Studiorum, Università di Bologna, Bologna, ItalyAbstract: By mimicking Nature, we can design and synthesize inorganic smart materials that are reactive to biological tissues. These smart materials can be utilized to design innovative third-generation biomaterials, which are able to not only optimize their interaction with biological tissues and environment, but also mimic biogenic materials in their functionalities. The biomedical applications involve increasing the biomimetic levels from chemical composition, structural organization, morphology, mechanical behavior, nanostructure, and bulk and surface chemical–physical properties until the surface becomes bioreactive and stimulates cellular materials. The chemical–physical characteristics of biogenic hydroxyapatites from bone and tooth have been described, in order to point out the elective sides, which are important to reproduce the design of a new biomimetic synthetic hydroxyapatite. This review outlines the evolving applications of biomimetic synthetic calcium phosphates, details the main characteristics of bone and tooth, where the calcium phosphates are present, and discusses the chemical–physical characteristics of biomimetic calcium phosphates, methods of synthesizing them, and some of their biomedical applications.Keywords: hydroxyapatite, nanocrystals, biomimetism, biomaterials, drug delivery, remineralization

  15. Evolving application of biomimetic nanostructured hydroxyapatite.

    Science.gov (United States)

    Roveri, Norberto; Iafisco, Michele

    2010-11-09

    By mimicking Nature, we can design and synthesize inorganic smart materials that are reactive to biological tissues. These smart materials can be utilized to design innovative third-generation biomaterials, which are able to not only optimize their interaction with biological tissues and environment, but also mimic biogenic materials in their functionalities. The biomedical applications involve increasing the biomimetic levels from chemical composition, structural organization, morphology, mechanical behavior, nanostructure, and bulk and surface chemical-physical properties until the surface becomes bioreactive and stimulates cellular materials. The chemical-physical characteristics of biogenic hydroxyapatites from bone and tooth have been described, in order to point out the elective sides, which are important to reproduce the design of a new biomimetic synthetic hydroxyapatite. This review outlines the evolving applications of biomimetic synthetic calcium phosphates, details the main characteristics of bone and tooth, where the calcium phosphates are present, and discusses the chemical-physical characteristics of biomimetic calcium phosphates, methods of synthesizing them, and some of their biomedical applications.

  16. Epidemic spreading on evolving signed networks

    Science.gov (United States)

    Saeedian, M.; Azimi-Tafreshi, N.; Jafari, G. R.; Kertesz, J.

    2017-02-01

    Most studies of disease spreading consider the underlying social network as obtained without the contagion, though epidemic influences people's willingness to contact others: A "friendly" contact may be turned to "unfriendly" to avoid infection. We study the susceptible-infected disease-spreading model on signed networks, in which each edge is associated with a positive or negative sign representing the friendly or unfriendly relation between its end nodes. In a signed network, according to Heider's theory, edge signs evolve such that finally a state of structural balance is achieved, corresponding to no frustration in physics terms. However, the danger of infection affects the evolution of its edge signs. To describe the coupled problem of the sign evolution and disease spreading, we generalize the notion of structural balance by taking into account the state of the nodes. We introduce an energy function and carry out Monte Carlo simulations on complete networks to test the energy landscape, where we find local minima corresponding to the so-called jammed states. We study the effect of the ratio of initial friendly to unfriendly connections on the propagation of disease. The steady state can be balanced or a jammed state such that a coexistence occurs between susceptible and infected nodes in the system.

  17. Orbital Decay in Binaries with Evolved Stars

    Science.gov (United States)

    Sun, Meng; Arras, Phil; Weinberg, Nevin N.; Troup, Nicholas; Majewski, Steven R.

    2018-01-01

    Two mechanisms are often invoked to explain tidal friction in binary systems. The ``dynamical tide” is the resonant excitation of internal gravity waves by the tide, and their subsequent damping by nonlinear fluid processes or thermal diffusion. The ``equilibrium tide” refers to non-resonant excitation of fluid motion in the star’s convection zone, with damping by interaction with the turbulent eddies. There have been numerous studies of these processes in main sequence stars, but less so on the subgiant and red giant branches. Motivated by the newly discovered close binary systems in the Apache Point Observatory Galactic Evolution Experiment (APOGEE-1), we have performed calculations of both the dynamical and equilibrium tide processes for stars over a range of mass as the star’s cease core hydrogen burning and evolve to shell burning. Even for stars which had a radiative core on the main sequence, the dynamical tide may have very large amplitude in the newly radiative core in post-main sequence, giving rise to wave breaking. The resulting large dynamical tide dissipation rate is compared to the equilibrium tide, and the range of secondary masses and orbital periods over which rapid orbital decay may occur will be discussed, as well as applications to close APOGEE binaries.

  18. UKAEA'S evolving contract philosophy

    Energy Technology Data Exchange (ETDEWEB)

    Nicol, R. D. [UK Atomic Energy Authority, UKAEA, Harwell, Oxfordshire (United Kingdom)

    2003-07-01

    The United Kingdom Atomic Energy Authority (UKAEA) has gone through fundamental change over the last ten years. At the heart of this change has been UKAEA's relationship with the contracting and supply market. This paper describes the way in which UKAEA actively developed the market to support the decommissioning programme, and how the approach to contracting has evolved as external pressures and demands have changed. UKAEA's pro-active approach to industry has greatly assisted the development of a healthy, competitive market for services supporting decommissioning in the UK. There have been difficult changes and many challenges along the way, and some retrenchment was necessary to meet regulatory requirements. Nevertheless, UKAEA has sustained a high level of competition - now measured in terms of competed spend as a proportion of competable spend - with annual out-turns consistently over 80%. The prime responsibility for market development will pass to the new Nuclear Decommissioning Authority (NDA) in 2005, as the owner, on behalf of the Government, of the UK's civil nuclear liabilities. The preparatory work for the NDA indicates that the principles established by UKAEA will be carried forward. (author)

  19. Beliefs about the use of baby walkers Crenças sobre o uso do andador infantil

    Directory of Open Access Journals (Sweden)

    Paula S. C. Chagas

    2011-08-01

    Full Text Available OBJECTIVES: To understand the opinion of the parents about the baby walker and compare the age of gait acquisition between infants that used a walker and those that did not. METHODS: In this quali-quantitative study, an interview involving a semi-structured questionnaire was carried out with 26 parents, 14 of whose infants used the equipment (BWG and 12 of whose infants did not (NBWG prior to gait acquisition. After extensive content analysis, categories for interpreting the results emerged. For data triangulation, the age of gait acquisition was documented by weekly telephone contact. Student's t-test was used for comparison between groups with a significance level of α=0.05. RESULTS: The following categories were identified in the parents' reports: a information about the baby walker; b doubt/decision to use it vs. certainty about not using it; c beliefs about the use of a baby-walker; and d benefits and harm from use. The age of independent gait acquisition did not differ between groups (p=0.837: BWG initiated gait at 376.17 (SD=32.62 days and NBWG did so at 378.75 (SD=27.99 days. CONCLUSIONS: The beliefs and feelings that permeate the decision to use a baby walker illustrate the different rationales adopted by parents about the role of this equipment in the child's development of gait and autonomy. The use of a baby walker did not influence the age of gait acquisition. The results broaden the understanding of choices that influence child-rearing practices prior to gait acquisition.OBJETIVOS: Conhecer a opinião dos pais sobre o uso do andador infantil e comparar a idade de aquisição da marcha independente entre os lactentes que usaram e os que não usaram o andador. MÉTODOS: Neste estudo qualiquantitativo, realizou-se entrevista com questionário semiestruturado com 26 pais, 14 de lactentes que usaram (GUAI e 12 dos que não usaram o equipamento (GNUAI antes da aquisição da marcha. Empregou-se análise de conteúdo, a partir da qual

  20. On the initial value problem for the wave equation in Friedmann-Robertson-Walker space-times.

    Science.gov (United States)

    Abbasi, Bilal; Craig, Walter

    2014-09-08

    The propagator W(t0,t1)(g,h) for the wave equation in a given space-time takes initial data (g(x),h(x)) on a Cauchy surface {(t,x) : t=t0} and evaluates the solution (u(t1,x),∂ tu(t1,x)) at other times t1. The Friedmann-Robertson-Walker space-times are defined for t0,t1>0, whereas for t0→0, there is a metric singularity. There is a spherical means representation for the general solution of the wave equation with the Friedmann-Robertson-Walker background metric in the three spatial dimensional cases of curvature K=0 and K=-1 given by S. Klainerman and P. Sarnak. We derive from the expression of their representation three results about the wave propagator for the Cauchy problem in these space-times. First, we give an elementary proof of the sharp rate of time decay of solutions with compactly supported data. Second, we observe that the sharp Huygens principle is not satisfied by solutions, unlike in the case of three-dimensional Minkowski space-time (the usual Huygens principle of finite propagation speed is satisfied, of course). Third, we show that for 00 emanating from the space-time singularity at t=0. Under reflection t→-t, the Friedmann-Robertson-Walker metric gives a space-time metric for tspace-times which exist for all [Formula: see text] and [Formula: see text], where in conformally regularized coordinates, these solutions are continuous through the singularity t=0 of space-time, taking on specified data u(0,⋅)=g(⋅) at the singular time.

  1. Sesquiterpene lactones of Moquiniastrum polymorphum subsp. floccosum have antineoplastic effects in Walker-256 tumor-bearing rats.

    Science.gov (United States)

    Martins, Gracianny Gomes; Lívero, Francislaine Aparecida dos Reis; Stolf, Aline Maria; Kopruszinski, Caroline Machado; Cardoso, Cibele Campos; Beltrame, Olair Carlos; Queiroz-Telles, José Ederaldo; Strapasson, Regiane Lauriano Batista; Stefanello, Maria Élida Alves; Oude-Elferink, Ronald; Acco, Alexandra

    2015-02-25

    This study aimed to evaluate the in vivo antitumor actions and toxicity of the dichloromethane fraction (F1B) of Moquiniastrum polymorphum subsp. floccosum (formerly Gochnatia polymorpha ssp. floccosa), composed of sesquiterpene lactones, against Walker-256 carcinosarcoma in rats. Male Wistar rats received 100 mg kg(-1) F1B per day orally for 16 days after subcutaneous inoculation of Walker-256 cells in the pelvic limb. The tumor progression was monitored, and after treatment, tumor weight, oxidative stress, plasma biochemistry, inflammatory parameters, gene expression and histology of tumor and/or liver were evaluated. The toxicity of F1B was analyzed through the relative weight of organs. Additionally, an LD50 test was performed in mice. F1B treatment significantly reduced tumor volume and weight. There was no difference in oxidative stress in tumor tissue after treatment. F1B treatment modified hepatic glutathione and superoxide dismutase, and normalized plasma glucose, alkaline phosphatase, and amylase. F1B did not affect the activity of myeloperoxidase and N-acetylglucosaminidase or the nitric oxide levels in tumor tissue. However, F1B decreased the tumor necrosis factor (TNF)-α levels. Additionally, F1B increased apoptosis in the tumor, mediated by up-regulation of the p53 and Bax gene expression. No clinical signs of toxicity or death were observed in the rats treated with F1B. The LD50 calculated for mice was 1209 mg kg(-1). F1B, which is rich in sesquiterpene lactones, showed antitumor activity against Walker-256 carcinosarcoma. This effect may be, at least in part, related to the induction of apoptosis and inhibition of TNF-α signaling. Copyright © 2015. Published by Elsevier Ireland Ltd.

  2. [Fragile X syndrome with Dandy-Walker variant: a clinical study of oral and written communicative manifestations].

    Science.gov (United States)

    Lamônica, Dionísia Aparecida Cusin; Ferraz, Plínio Marcos Duarte Pinto; Ferreira, Amanda Tragueta; Prado, Lívia Maria do; Abramides, Dagma Venturini Marquez; Gejão, Mariana Germano

    2011-01-01

    The Fragile X syndrome is the most frequent cause of inherited intellectual disability. The Dandy-Walker variant is a specific constellation of neuroradiological findings. The present study reports oral and written communication findings in a 15-year-old boy with clinical and molecular diagnosis of Fragile X syndrome and neuroimaging findings consistent with Dandy-Walker variant. The speech-language pathology and audiology evaluation was carried out using the Communicative Behavior Observation, the Phonology assessment of the ABFW - Child Language Test, the Phonological Abilities Profile, the Test of School Performance, and the Illinois Test of Psycholinguistic Abilities. Stomatognathic system and hearing assessments were also performed. It was observed: phonological, semantic, pragmatic and morphosyntactic deficits in oral language; deficits in psycholinguistic abilities (auditory reception, verbal expression, combination of sounds, auditory and visual sequential memory, auditory closure, auditory and visual association); and morphological and functional alterations in the stomatognathic system. Difficulties in decoding the graphical symbols were observed in reading. In writing, the subject presented omissions, agglutinations and multiple representations with the predominant use of vowels, besides difficulties in visuo-spatial organization. In mathematics, in spite of the numeric recognition, the participant didn't accomplish arithmetic operations. No alterations were observed in the peripheral hearing evaluation. The constellation of behavioral, cognitive, linguistic and perceptual symptoms described for Fragile X syndrome, in addition to the structural central nervous alterations observed in the Dandy-Walker variant, caused outstanding interferences in the development of communicative abilities, in reading and writing learning, and in the individual's social integration.

  3. Management of Dandy-Walker complex-associated infant hydrocephalus by combined endoscopic third ventriculostomy and choroid plexus cauterization.

    Science.gov (United States)

    Warf, Benjamin C; Dewan, Michael; Mugamba, John

    2011-10-01

    Dandy-Walker complex (DWC) is a continuum of congenital anomalies comprising Dandy-Walker malformation (DWM), Dandy-Walker variant (DWV), Blake pouch cyst, and mega cisterna magna (MCM). Hydrocephalus is variably associated with each of these, and DWC-associated hydrocephalus has mostly been treated by shunting, often with 2-compartment shunting. There are few reports of management by endoscopic third ventriculostomy (ETV). This study is the largest series of DWC or DWM-associated hydrocephalus treated by ETV, and the first report of treatment by combined ETV and choroid plexus cauterization (ETV/CPC) in young infants with this association. A retrospective review of the CURE Children's Hospital of Uganda clinical database between 2004 and 2010 identified 45 patients with DWC confirmed by CT scanning (25 with DWM, 17 with DWV, and 3 with MCM) who were treated for hydrocephalus by ETV/CPC. Three were excluded because of other potential causes of hydrocephalus (2 postinfectious and 1 posthemorrhagic). The median age at treatment was 5 months (88% of patients were younger than 12 months). There was a 2.4:1 male predominance among patients with DWV. An ETV/CPC (ETV only in one) was successful with no further operations in 74% (mean and median follow-up 24.2 and 20 months, respectively [range 6-65 months]). The rate of success was 74% for DWM, 73% for DWV, and 100% for MCM; 95% had an open aqueduct, and none required posterior fossa shunting. Endoscopic treatment of DWC-associated hydrocephalus should be strongly considered as the primary management in place of the historical standard of creating shunt dependence.

  4. Pharmacokinetic/pharmacodynamic modeling of etoposide tumor growth inhibitory effect in Walker-256 tumor-bearing rat model using free intratumoral drug concentrations.

    Science.gov (United States)

    Pigatto, Maiara Cássia; Roman, Renatha Menti; Carrara, Letizia; Buffon, Andréia; Magni, Paolo; Dalla Costa, Teresa

    2017-01-15

    The purpose of this study was to establish a population pharmacokinetic/pharmacodynamic (PK/PD) model linking etoposide free tumor and total plasma concentrations to the inhibition of solid tumor growth in rats. Walker-256 tumor cells were inoculated subcutaneously in the right flank of Wistar rats, which were randomly divided in control and two treated groups that received etoposide 5 or 10mg/kg i.v. bolus every day for 8 and 4days, respectively, and tumor volume was monitored daily for 30days. The plasma and intratumoral concentrations-time profiles were obtained from a previous study and were modeled by a four-compartment population pharmacokinetic (popPK) model. PK/PD analysis was conducted using MONOLIX v.4.3.3 on average data and by mean of a nonlinear mixed-effect model. PK/PD data were analyzed using a modification of Simeoni Tumor Growth Inhibition (TGI) model by introduction of an Emax function to take into account the concentration dependency of k2variable parameter (variable potency). The Simeoni TGI-Emax model was capable to fit schedule-dependent antitumor effects using the tumor growth curves from the control and two different administered schedules. The PK/PD model was capable of describing the tumor growth inhibition using total plasma or free tumor concentrations, resulting in higher k2max (maximal potency) for free concentrations (25.8mL·μg(-1)·day(-1) - intratumoral vs. 12.6mL·μg(-1)·day(-1) total plasma). These findings indicate that the plasma concentration may not be a good surrogate for pharmacologically active free tumor concentrations, emphasizing the importance of knowing drug tumor penetration to choose the best antitumor therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. The Quality of Lagged Products and Autoregressive Yule–Walker Models as Autocorrelation Estimates

    NARCIS (Netherlands)

    Broersen, P.M.T.

    2009-01-01

    The sample autocorrelation function is defined by the mean lagged products (LPs) of random observations. It is the inverse Fourier transform of the raw periodogram. Both contain the same information, and the quality of the full-length sample autocorrelation to represent random data is as poor as

  6. Simple unified view of branching process statistics: Random walks in balanced logarithmic potentials

    Science.gov (United States)

    di Santo, Serena; Villegas, Pablo; Burioni, Raffaella; Muñoz, Miguel A.

    2017-03-01

    We revisit the problem of deriving the mean-field values of avalanche exponents in systems with absorbing states. These are well known to coincide with those of unbiased branching processes. Here we show that for at least four different universality classes (directed percolation, dynamical percolation, the voter model or compact directed percolation class, and the Manna class of stochastic sandpiles) this common result can be obtained by mapping the corresponding Langevin equations describing each of them into a random walker confined to the origin by a logarithmic potential. We report on the emergence of nonuniversal continuously varying exponent values stemming from the presence of small external driving - that might induce avalanche merging - that, to the best of our knowledge, has not been noticed in the past. Many of the other results derived here appear in the literature as independently derived for individual universality classes or for the branching process itself. Still, we believe that a simple and unified perspective as the one presented here can help (1) clarify the overall picture, (2) underline the superuniversality of the behavior as well as the dependence on external driving, and (3) avoid the common existing confusion between unbiased branching processes (equivalent to a random walker in a balanced logarithmic potential) and standard (unconfined) random walkers.

  7. The construction of identity in Alice Walker's The Color Purple and Zora Neale Hurston's Their Eyes Were Watching God

    OpenAIRE

    Nodari, Janice Inês

    2002-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão. Programa de Pós-Graduação em Letras/Inglês e Literatura Correspondente. Este estudo tem por objetivo analisar a construção da identidade sofrida por Celie, a personagem principal no livro The Color Purple (1982) de Alice Walker, e Janie, a personagem principal no livro Their Eyes Were Watching God (1937) de Zora Neale Hurston. A abordagem empregada favorece a investigação dos aspectos: jorna...

  8. Neuropsychological Function in a Case of Dandy-Walker Variant in a 68-Year-Old Veteran.

    Science.gov (United States)

    Gross, Patricia L; Kays, Jill L; Shura, Robert D

    2016-01-01

    Dandy-Walker syndrome (DWS) is a congenital brain malformation that is characterized by partial or complete agenesis of the cerebellar vermis and cystic dilatation of the 4th ventricle that shifts ventrolaterally to displace the cerebellar hemispheres. This case is a 68-year-old male veteran with complaints of new-onset cognitive disorder who was found to have previously unsuspected DWS on head computed tomography. This is one of the first case studies to present complete neuropsychological test results in a veteran with DWS. Despite the level of abnormality on imaging, the veteran functioned well until onset of mild cognitive impairments in late adulthood.

  9. Comparing Arc-shaped Feet and Rigid Ankles with Flat Feet and Compliant Ankles for a Dynamic Walker

    DEFF Research Database (Denmark)

    Kuhlemann, Ilyas; Matthias Braun, Jan; Wörgötter, Florentin

    2014-01-01

    In this paper we show that exchanging curved feet and rigid ankles by at feet and compliant ankles improves the range of gait parameters for a bipedal dynamic walker. The new lower legs were designed such that they t to the old set-up, allowing for a direct and quantitative comparison. The dynamic...... walking robot RunBot, controlled by an reflexive neural network, uses only few sensors for generating its stable gait. The results show that at feet and compliant ankles extend RunBot's parameter range especially to more leaning back postures. They also allow the robot to stably walk over obstacles...

  10. Simulating Species Richness Using Agents with Evolving Niches, with an Example of Galápagos Plants

    Directory of Open Access Journals (Sweden)

    Randall B. Boone

    2010-01-01

    Full Text Available I sought to evolve plant species richness patterns on 22 Galápagos Islands, Ecuador, as an exploration of the utility of evolutionary computation and an agent-based approach in biogeography research. The simulation was spatially explicit, where agents were plant monocultures defined by three niche dimensions, lava (yes or no, elevation, and slope. Niches were represented as standard normal curves subjected to selection pressure, where neighboring plants bred if their niches overlapped sufficiently, and were considered the same species, otherwise they were different species. Plants that bred produced seeds with mutated niches. Seeds dispersed locally and longer distances, and established if the habitat was appropriate given the seed's niche. From a single species colonizing a random location, hundreds of species evolved to fill the islands. Evolved plant species richness agreed very well with observed plant species richness. I review potential uses of an agent-based representation of evolving niches in biogeography research.

  11. Quantum mechanics in an evolving Hilbert space

    Science.gov (United States)

    Artacho, Emilio; O'Regan, David D.

    2017-03-01

    Many basis sets for electronic structure calculations evolve with varying external parameters, such as moving atoms in dynamic simulations, giving rise to extra derivative terms in the dynamical equations. Here we revisit these derivatives in the context of differential geometry, thereby obtaining a more transparent formalization, and a geometrical perspective for better understanding the resulting equations. The effect of the evolution of the basis set within the spanned Hilbert space separates explicitly from the effect of the turning of the space itself when moving in parameter space, as the tangent space turns when moving in a curved space. New insights are obtained using familiar concepts in that context such as the Riemann curvature. The differential geometry is not strictly that for curved spaces as in general relativity, a more adequate mathematical framework being provided by fiber bundles. The language used here, however, will be restricted to tensors and basic quantum mechanics. The local gauge implied by a smoothly varying basis set readily connects with Berry's formalism for geometric phases. Generalized expressions for the Berry connection and curvature are obtained for a parameter-dependent occupied Hilbert space spanned by nonorthogonal Wannier functions. The formalism is applicable to basis sets made of atomic-like orbitals and also more adaptative moving basis functions (such as in methods using Wannier functions as intermediate or support bases), but should also apply to other situations in which nonorthogonal functions or related projectors should arise. The formalism is applied to the time-dependent quantum evolution of electrons for moving atoms. The geometric insights provided here allow us to propose new finite-difference time integrators, and also better understand those already proposed.

  12. The evolving role of tiotropium in asthma

    Directory of Open Access Journals (Sweden)

    McIvor ER

    2017-08-01

    Full Text Available Emma R McIvor,1 R Andrew McIvor2 1Queen’s University, Belfast, UK; 2Department of Medicine, McMaster University, Firestone Institute for Respiratory Health, Hamilton, Ontario, Canada Abstract: Tiotropium is a long-acting muscarinic antagonist (LAMA that exerts its bronchodilatory effect by blocking endogenous acetylcholine receptors in the airways. Its safety and efficacy are well established for the treatment of COPD, and it is now being recognized for its role in improving lung function and control in asthma. This review discusses the evolving role of tiotropium delivered by the Respimat® in patients across the range of asthma severities and ages, and provides an overview of safety and efficacy data. Tiotropium is the only LAMA currently approved for the treatment of asthma, and evidence from a large-scale clinical trial program, including several Phase III studies in adults, has demonstrated that tiotropium improves lung function and asthma control, with a safety profile comparable with that of placebo. Clinical trials in adolescent patients (aged 12–17 years have also shown improvements in lung function and trends toward improved asthma control. Of note, the efficacy and safety profiles are consistent regardless of baseline characteristics and phenotype. Given the large and growing body of evidence, it is likely that as clinical experience with tiotropium increases, this treatment may possibly emerge as the key choice for add-on therapy to inhaled corticosteroids/long-acting β2-agonists, and in patients who do not tolerate long-acting bronchodilators or other medications, in the future. Keywords: tiotropium, anticholinergics, asthma, efficacy

  13. Emergent spacetime in stochastically evolving dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Afshordi, Niayesh [Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, ON, N2L 2Y5 (Canada); Department of Physics and Astronomy, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada); HEPCOS, Department of Physics, SUNY at Buffalo, Buffalo, NY 14260-1500 (United States); Stojkovic, Dejan, E-mail: ds77@buffalo.edu [Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, ON, N2L 2Y5 (Canada); HEPCOS, Department of Physics, SUNY at Buffalo, Buffalo, NY 14260-1500 (United States)

    2014-12-12

    Changing the dimensionality of the space–time at the smallest and largest distances has manifold theoretical advantages. If the space is lower dimensional in the high energy regime, then there are no ultraviolet divergencies in field theories, it is possible to quantize gravity, and the theory of matter plus gravity is free of divergencies or renormalizable. If the space is higher dimensional at cosmological scales, then some cosmological problems (including the cosmological constant problem) can be attacked from a completely new perspective. In this paper, we construct an explicit model of “evolving dimensions” in which the dimensions open up as the temperature of the universe drops. We adopt the string theory framework in which the dimensions are fields that live on the string worldsheet, and add temperature dependent mass terms for them. At the Big Bang, all the dimensions are very heavy and are not excited. As the universe cools down, dimensions open up one by one. Thus, the dimensionality of the space we live in depends on the energy or temperature that we are probing. In particular, we provide a kinematic Brandenberger–Vafa argument for how a discrete causal set, and eventually a continuum (3+1)-dim spacetime along with Einstein gravity emerges in the Infrared from the worldsheet action. The (3+1)-dim Planck mass and the string scale become directly related, without any compactification. Amongst other predictions, we argue that LHC might be blind to new physics even if it comes at the TeV scale. In contrast, cosmic ray experiments, especially those that can register the very beginning of the shower, and collisions with high multiplicity and density of particles, might be sensitive to the dimensional cross-over.

  14. Emergent spacetime in stochastically evolving dimensions

    Science.gov (United States)

    Afshordi, Niayesh; Stojkovic, Dejan

    2014-12-01

    Changing the dimensionality of the space-time at the smallest and largest distances has manifold theoretical advantages. If the space is lower dimensional in the high energy regime, then there are no ultraviolet divergencies in field theories, it is possible to quantize gravity, and the theory of matter plus gravity is free of divergencies or renormalizable. If the space is higher dimensional at cosmological scales, then some cosmological problems (including the cosmological constant problem) can be attacked from a completely new perspective. In this paper, we construct an explicit model of ;evolving dimensions; in which the dimensions open up as the temperature of the universe drops. We adopt the string theory framework in which the dimensions are fields that live on the string worldsheet, and add temperature dependent mass terms for them. At the Big Bang, all the dimensions are very heavy and are not excited. As the universe cools down, dimensions open up one by one. Thus, the dimensionality of the space we live in depends on the energy or temperature that we are probing. In particular, we provide a kinematic Brandenberger-Vafa argument for how a discrete causal set, and eventually a continuum (3 + 1)-dim spacetime along with Einstein gravity emerges in the Infrared from the worldsheet action. The (3 + 1)-dim Planck mass and the string scale become directly related, without any compactification. Amongst other predictions, we argue that LHC might be blind to new physics even if it comes at the TeV scale. In contrast, cosmic ray experiments, especially those that can register the very beginning of the shower, and collisions with high multiplicity and density of particles, might be sensitive to the dimensional cross-over.

  15. Emergent spacetime in stochastically evolving dimensions

    Directory of Open Access Journals (Sweden)

    Niayesh Afshordi

    2014-12-01

    Full Text Available Changing the dimensionality of the space–time at the smallest and largest distances has manifold theoretical advantages. If the space is lower dimensional in the high energy regime, then there are no ultraviolet divergencies in field theories, it is possible to quantize gravity, and the theory of matter plus gravity is free of divergencies or renormalizable. If the space is higher dimensional at cosmological scales, then some cosmological problems (including the cosmological constant problem can be attacked from a completely new perspective. In this paper, we construct an explicit model of “evolving dimensions” in which the dimensions open up as the temperature of the universe drops. We adopt the string theory framework in which the dimensions are fields that live on the string worldsheet, and add temperature dependent mass terms for them. At the Big Bang, all the dimensions are very heavy and are not excited. As the universe cools down, dimensions open up one by one. Thus, the dimensionality of the space we live in depends on the energy or temperature that we are probing. In particular, we provide a kinematic Brandenberger–Vafa argument for how a discrete causal set, and eventually a continuum (3+1-dim spacetime along with Einstein gravity emerges in the Infrared from the worldsheet action. The (3+1-dim Planck mass and the string scale become directly related, without any compactification. Amongst other predictions, we argue that LHC might be blind to new physics even if it comes at the TeV scale. In contrast, cosmic ray experiments, especially those that can register the very beginning of the shower, and collisions with high multiplicity and density of particles, might be sensitive to the dimensional cross-over.

  16. Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

    Science.gov (United States)

    Diaz, Carlos E., Jr.

    2015-01-01

    This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

  17. Information filtering in evolving online networks

    Science.gov (United States)

    Chen, Bo-Lun; Li, Fen-Fen; Zhang, Yong-Jun; Ma, Jia-Lin

    2018-02-01

    Recommender systems use the records of users' activities and profiles of both users and products to predict users' preferences in the future. Considerable works towards recommendation algorithms have been published to solve the problems such as accuracy, diversity, congestion, cold-start, novelty, coverage and so on. However, most of these research did not consider the temporal effects of the information included in the users' historical data. For example, the segmentation of the training set and test set was completely random, which was entirely different from the real scenario in recommender systems. More seriously, all the objects are treated as the same, regardless of the new, the popular or obsoleted products, so do the users. These data processing methods always lose useful information and mislead the understanding of the system's state. In this paper, we detailed analyzed the difference of the network structure between the traditional random division method and the temporal division method on two benchmark data sets, Netflix and MovieLens. Then three classical recommendation algorithms, Global Ranking method, Collaborative Filtering and Mass Diffusion method, were employed. The results show that all these algorithms became worse in all four key indicators, ranking score, precision, popularity and diversity, in the temporal scenario. Finally, we design a new recommendation algorithm based on both users' and objects' first appearance time in the system. Experimental results showed that the new algorithm can greatly improve the accuracy and other metrics.

  18. De Novo 3q22.3q24 Microdeletion in a Patient With Blepharophimosis–Ptosis–Epicanthus Inversus Syndrome, Dandy-Walker Malformation, and Wisconsin Syndrome

    Science.gov (United States)

    Ramineni, Anand

    2016-01-01

    Interstitial deletions affecting the long arm of chromosome 3 have been associated with a broad phenotype. This has included the features of blepharophimosis–ptosis–epicanthus inversus syndrome, Dandy-Walker malformation, and the rare Wisconsin syndrome. The authors report a young female patient presenting with features consistent with all 3 of these syndromes. This has occurred in the context of a de novo 3q22.3q24 microdeletion including FOXL2, ZIC1, and ZIC4. This patient provides further evidence for the role of ZIC1 and ZIC4 in Dandy-Walker malformation and is the third reported case of Dandy-Walker malformation to have associated corpus callosum thinning. This patient is also only the seventh to be reported with the rare Wisconsin syndrome phenotype. PMID:28503614

  19. De Novo 3q22.3q24 Microdeletion in a Patient With Blepharophimosis-Ptosis-Epicanthus Inversus Syndrome, Dandy-Walker Malformation, and Wisconsin Syndrome.

    Science.gov (United States)

    Ramineni, Anand; Coman, David

    2016-01-01

    Interstitial deletions affecting the long arm of chromosome 3 have been associated with a broad phenotype. This has included the features of blepharophimosis-ptosis-epicanthus inversus syndrome, Dandy-Walker malformation, and the rare Wisconsin syndrome. The authors report a young female patient presenting with features consistent with all 3 of these syndromes. This has occurred in the context of a de novo 3q22.3q24 microdeletion including FOXL2 , ZIC1 , and ZIC4 . This patient provides further evidence for the role of ZIC1 and ZIC4 in Dandy-Walker malformation and is the third reported case of Dandy-Walker malformation to have associated corpus callosum thinning. This patient is also only the seventh to be reported with the rare Wisconsin syndrome phenotype.

  20. De Novo 3q22.3q24 Microdeletion in a Patient With Blepharophimosis–Ptosis–Epicanthus Inversus Syndrome, Dandy-Walker Malformation, and Wisconsin Syndrome

    Directory of Open Access Journals (Sweden)

    Anand Ramineni BSc, MBBS, GSCpMed

    2016-08-01

    Full Text Available Interstitial deletions affecting the long arm of chromosome 3 have been associated with a broad phenotype. This has included the features of blepharophimosis–ptosis–epicanthus inversus syndrome, Dandy-Walker malformation, and the rare Wisconsin syndrome. The authors report a young female patient presenting with features consistent with all 3 of these syndromes. This has occurred in the context of a de novo 3q22.3q24 microdeletion including FOXL2 , ZIC1 , and ZIC4 . This patient provides further evidence for the role of ZIC1 and ZIC4 in Dandy-Walker malformation and is the third reported case of Dandy-Walker malformation to have associated corpus callosum thinning. This patient is also only the seventh to be reported with the rare Wisconsin syndrome phenotype.

  1. Orthogonally Evolved AI to Improve Difficulty Adjustment in Video Games

    DEFF Research Database (Denmark)

    Hintze, Arend; Olson, Randal; Lehman, Joel Anthony

    2016-01-01

    (i.e. agents subject to fewer generations of evolution) make for easier opponents, while highly-evolved agents are more challenging to overcome. In this publication we test a new approach for difficulty adjustment in games: orthogonally evolved AI, where the player receives support from collaborating...... opponents. Furthermore, human interaction can modulate (and be informed by) the performance and behavior of collaborating agents. In this way, orthogonally evolved AI both facilitates smoother difficulty adjustment and enables new game experiences....

  2. Altered stoichiometry of an evolved RNA aptamer.

    Science.gov (United States)

    Ohuchi, Shoji; Suess, Beatrix

    2017-12-28

    Inhibitory aptamers against a protein are promising as antagonistic reagents and repressive genetic components. Typically, improvement of such aptamers is achieved by acquiring higher binding affinity. Here, we report an alternative mechanism for the improvement of aptamer activity. Recently, we reported a transcriptional activator based on an inhibitory RNA aptamer against lambda cI repressor. We improved the aptamer through in vitro selection (SELEX) from a randomly mutagenized aptamer pool, followed by in vivo screening and truncation. Biochemical analyses indicated that the activity improvement was achieved by alteration of the complex formation stoichiometry, rather than by higher affinity or expression. Our results suggest an alternative strategy for improving aptamer activity. Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  3. Evolving R Coronae Borealis Stars with MESA

    Science.gov (United States)

    Clayton, Geoffrey C.; Lauer, Amber; Chatzopoulos, Emmanouil; Frank, Juhan

    2018-01-01

    being a WD. Solving the mystery of how the RCB stars evolve will lead to a better understanding of other important types of stellar merger events such as Type Ia SNe.

  4. Disparate requirements for the Walker A and B ATPase motifs ofhuman RAD51D in homologous recombination

    Energy Technology Data Exchange (ETDEWEB)

    Wiese, Claudia; Hinz, John M.; Tebbs, Robert S.; Nham, Peter B.; Urbin, Salustra S.; Collins, David W.; Thompson, Larry H.; Schild, David

    2006-04-21

    In vertebrates, homologous recombinational repair (HRR) requires RAD51 and five RAD51 paralogs (XRCC2, XRCC3, RAD51B, RAD51C, and RAD51D) that all contain conserved Walker A and B ATPase motifs. In human RAD51D we examined the requirement for these motifs in interactions with XRCC2 and RAD51C, and for survival of cells in response to DNA interstrand crosslinks. Ectopic expression of wild type human RAD51D or mutants having a non-functional A or B motif was used to test for complementation of a rad51d knockout hamster CHO cell line. Although A-motif mutants complement very efficiently, B-motif mutants do not. Consistent with these results, experiments using the yeast two- and three-hybrid systems show that the interactions between RAD51D and its XRCC2 and RAD51C partners also require a functional RAD51D B motif, but not motif A. Similarly, hamster Xrcc2 is unable to bind to the non-complementing human RAD51D B-motif mutants in co-immunoprecipitation assays. We conclude that a functional Walker B motif, but not A motif, is necessary for RAD51D's interactions with other paralogs and for efficient HRR. We present a model in which ATPase sites are formed in a bipartite manner between RAD51D and other RAD51 paralogs.

  5. Autoregressive-moving-average hidden Markov model for vision-based fall prediction-An application for walker robot.

    Science.gov (United States)

    Taghvaei, Sajjad; Jahanandish, Mohammad Hasan; Kosuge, Kazuhiro

    2017-01-01

    Population aging of the societies requires providing the elderly with safe and dependable assistive technologies in daily life activities. Improving the fall detection algorithms can play a major role in achieving this goal. This article proposes a real-time fall prediction algorithm based on the acquired visual data of a user with walking assistive system from a depth sensor. In the lack of a coupled dynamic model of the human and the assistive walker a hybrid "system identification-machine learning" approach is used. An autoregressive-moving-average (ARMA) model is fitted on the time-series walking data to forecast the upcoming states, and a hidden Markov model (HMM) based classifier is built on the top of the ARMA model to predict falling in the upcoming time frames. The performance of the algorithm is evaluated through experiments with four subjects including an experienced physiotherapist while using a walker robot in five different falling scenarios; namely, fall forward, fall down, fall back, fall left, and fall right. The algorithm successfully predicts the fall with a rate of 84.72%.

  6. Maceral Characteristics and Vitrinite Reflectance Variation of The High Rank Coals, South Walker Creek, Bowen Basin, Australia

    Directory of Open Access Journals (Sweden)

    Asep K. Permana

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i2.156The Permian coals of the South Walker Creek area, with a vitrinite reflectance (Rvmax of 1.7 to 1.95% (low-volatile bituminous to semi-anthracite, are one of the highest rank coals currently mined in the Bowen Basin for the pulverized coal injection (PCI market. Studies of petrology of this coal seam have identified that the maceral composition of the coals are dominated by inertinite with lesser vitrinite, and only minor amounts of liptinite. Clay minerals, quartz, and carbonates can be seen under the optical microscope. The mineral matter occurs in association with vitrinite and inertinite macerals as syngenetic and epigenetic mineral phases. The irregular pattern of the vitrinite reflectance profile from the top to the bottom of the seam may represent a response in the organic matter to an uneven heat distribution from such hydrothermal influence. Examination of the maceral and vitrinite reflectance characteristics suggest that the mineralogical variation within the coal seam at South Walker Creek may have been controlled by various geological processes, including sediment input into the peat swamp during deposition, mineralogical changes associated with the rank advance process or metamorphism, and/or hydrothermal effects due to post depositional fluid migration through the coal seam.

  7. Anandan quantum phase for a neutral particle with Fermi-Walker reference frame in the cosmic string background

    Science.gov (United States)

    Bakke, Knut; Furtado, C.

    2010-10-01

    We study geometric quantum phases in the relativistic and non-relativistic quantum dynamics of a neutral particle with a permanent magnetic dipole moment interacting with two distinct field configurations in a cosmic string spacetime. We consider the local reference frames of the observers are transported via Fermi-Walker transport and study the influence of the non-inertial effects on the phase shift of the wave function of the neutral particle due to the choice of this local frame. We show that the wave function of the neutral particle acquires non-dispersive relativistic and non-relativistic quantum geometric phases due to the topology of the spacetime, the interaction between the magnetic dipole moment with external fields and the spin-rotation coupling. However, due to the Fermi-Walker reference frame, no phase shift associated to the Sagnac effect appears in the quantum dynamics of a neutral particle. We show that in the absence of topological defect, the contribution to the quantum phase due to the spin-rotation coupling is equivalent to the Mashhoon effect in non-relativistic dynamics.

  8. Complete trisomy 9 with unusual phenotypic associations: Dandy-Walker malformation, cleft lip and cleft palate, cardiovascular abnormalities.

    Science.gov (United States)

    Tonni, Gabriele; Lituania, Mario; Chitayat, David; Bonasoni, Maria Paola; Keating, Sarah; Thompson, Megan; Shannon, Patrick

    2014-12-01

    Trisomy 9 is a rare chromosomal abnormality usually associated with first-trimester miscarriage; few fetuses survive until the second trimester. We report two new cases of complete trisomy 9 that both present unusual phenotypic associations, and we analyze the genetic pathway involved in this chromosomal abnormality. The first fetus investigated showed Dandy-Walker malformation, cleft lip, and cleft palate) at the second trimester scan. Cardiovascular abnormalities were characterized by a right-sided, U-shaped aortic arch associated with a ventricular septal defect (VSD). Symmetrical intrauterine growth restriction and multicystic dysplastic kidney disease were associated findings. The second fetus showed a dysmorphic face, bilateral cleft lip, hypoplastic corpus callosum, and a Dandy-Walker malformation. Postmortem examination revealed cardiovascular abnormalities such as persistent left superior vena cava draining into the coronary sinus, membranous ventricular septal defect, overriding aorta, pulmonary valve with two cusps and three sinuses, and the origin of the left subclavian artery distal to the junction of ductus arteriosus and aortic arch. Complete trisomy 9 may result in a wide spectrum of congenital abnormalities, and the presented case series contributes further details on the phenotype of this rare aneuploidy. Copyright © 2014. Published by Elsevier B.V.

  9. Changes in a cerebellar peduncle lesion in a patient with Dandy-Walker malformation: A diffusion tensor imaging study.

    Science.gov (United States)

    Lee, Ah Young; Jang, Sung Ho; Yeo, Sang Seok; Lee, Ensil; Cho, Yun Woo; Son, Su Min

    2013-02-15

    We report a patient with severe ataxia due to Dandy-Walker malformation, who showed functional recovery over 10 months corresponding to a change in a cerebellar peduncle lesion. A 20-month-old female patient who was diagnosed with Dandy-Walker syndrome and six age- and sex-matched healthy control subjects were enrolled. The superior cerebellar peduncle, the middle cerebellar peduncle, and the inferior cerebellar peduncle were evaluated using fractional anisotropy and the apparent diffusion coefficient. The patients' functional ambulation category was 0 at the initial visit, but improved to 2 at the follow-up evaluation, and Berg's balance scale score also improved from 0 to 7. Initial diffusion tensor tractography revealed that the inferior cerebellar peduncle was not detected, that the fractional anisotropy of the superior cerebellar peduncle and middle cerebellar peduncle decreased by two standard deviations below, and that the apparent diffusion coefficient increased by two standard deviations over normal control values. However, on follow-up diffusion tensor tractography, both inferior cerebellar peduncles could be detected, and the fractional anisotropy of superior cerebellar peduncle increased to within two standard deviations of normal controls. The functional improvement in this patient appeared to correspond to changes in these cerebellar peduncles. We believe that evaluating cerebellar peduncles using diffusion tensor imaging is useful in cases when a cerebellar peduncle lesion is suspected.

  10. Buses, cars, bicycles and walkers: the influence of the type of human transport on the flight responses of waterbirds.

    Directory of Open Access Journals (Sweden)

    Emily M McLeod

    Full Text Available One way to manage disturbance to waterbirds in natural areas where humans require access is to promote the occurrence of stimuli for which birds tolerate closer approaches, and so cause fewer responses. We conducted 730 experimental approaches to 39 species of waterbird, using five stimulus types (single walker, three walkers, bicycle, car and bus selected to mimic different human management options available for a controlled access, Ramsar-listed wetland. Across species, where differences existed (56% of 25 cases, motor vehicles always evoked shorter flight-initiation distances (FID than humans on foot. The influence of stimulus type on FID varied across four species for which enough data were available for complete cross-stimulus analysis. All four varied FID in relation to stimuli, differing in 4 to 7 of 10 possible comparisons. Where differences occurred, the effect size was generally modest, suggesting that managing stimulus type (e.g. by requiring people to use vehicles may have species-specific, modest benefits, at least for the waterbirds we studied. However, different stimulus types have different capacities to reduce the frequency of disturbance (i.e. by carrying more people and vary in their capacity to travel around important habitat.

  11. Genetic Correlations Greatly Increase Mutational Robustness and Can Both Reduce and Enhance Evolvability.

    Directory of Open Access Journals (Sweden)

    Sam F Greenbury

    2016-03-01

    Full Text Available Mutational neighbourhoods in genotype-phenotype (GP maps are widely believed to be more likely to share characteristics than expected from random chance. Such genetic correlations should strongly influence evolutionary dynamics. We explore and quantify these intuitions by comparing three GP maps-a model for RNA secondary structure, the HP model for protein tertiary structure, and the Polyomino model for protein quaternary structure-to a simple random null model that maintains the number of genotypes mapping to each phenotype, but assigns genotypes randomly. The mutational neighbourhood of a genotype in these GP maps is much more likely to contain genotypes mapping to the same phenotype than in the random null model. Such neutral correlations can be quantified by the robustness to mutations, which can be many orders of magnitude larger than that of the null model, and crucially, above the critical threshold for the formation of large neutral networks of mutationally connected genotypes which enhance the capacity for the exploration of phenotypic novelty. Thus neutral correlations increase evolvability. We also study non-neutral correlations: Compared to the null model, i If a particular (non-neutral phenotype is found once in the 1-mutation neighbourhood of a genotype, then the chance of finding that phenotype multiple times in this neighbourhood is larger than expected; ii If two genotypes are connected by a single neutral mutation, then their respective non-neutral 1-mutation neighbourhoods are more likely to be similar; iii If a genotype maps to a folding or self-assembling phenotype, then its non-neutral neighbours are less likely to be a potentially deleterious non-folding or non-assembling phenotype. Non-neutral correlations of type i and ii reduce the rate at which new phenotypes can be found by neutral exploration, and so may diminish evolvability, while non-neutral correlations of type iii may instead facilitate evolutionary exploration

  12. Genetic Correlations Greatly Increase Mutational Robustness and Can Both Reduce and Enhance Evolvability.

    Science.gov (United States)

    Greenbury, Sam F; Schaper, Steffen; Ahnert, Sebastian E; Louis, Ard A

    2016-03-01

    Mutational neighbourhoods in genotype-phenotype (GP) maps are widely believed to be more likely to share characteristics than expected from random chance. Such genetic correlations should strongly influence evolutionary dynamics. We explore and quantify these intuitions by comparing three GP maps-a model for RNA secondary structure, the HP model for protein tertiary structure, and the Polyomino model for protein quaternary structure-to a simple random null model that maintains the number of genotypes mapping to each phenotype, but assigns genotypes randomly. The mutational neighbourhood of a genotype in these GP maps is much more likely to contain genotypes mapping to the same phenotype than in the random null model. Such neutral correlations can be quantified by the robustness to mutations, which can be many orders of magnitude larger than that of the null model, and crucially, above the critical threshold for the formation of large neutral networks of mutationally connected genotypes which enhance the capacity for the exploration of phenotypic novelty. Thus neutral correlations increase evolvability. We also study non-neutral correlations: Compared to the null model, i) If a particular (non-neutral) phenotype is found once in the 1-mutation neighbourhood of a genotype, then the chance of finding that phenotype multiple times in this neighbourhood is larger than expected; ii) If two genotypes are connected by a single neutral mutation, then their respective non-neutral 1-mutation neighbourhoods are more likely to be similar; iii) If a genotype maps to a folding or self-assembling phenotype, then its non-neutral neighbours are less likely to be a potentially deleterious non-folding or non-assembling phenotype. Non-neutral correlations of type i) and ii) reduce the rate at which new phenotypes can be found by neutral exploration, and so may diminish evolvability, while non-neutral correlations of type iii) may instead facilitate evolutionary exploration and so

  13. Evolving paradigm for fab revenue optimization

    Science.gov (United States)

    Akella, Ramakrishna; Fridgeirsdottir, Kristin; Skumanich, Andrew

    2002-07-01

    Historically for semiconductor processing, defects have been considered in a separate class as yield detractors and significant effort goes into detection, analysis and monitoring of defects. With the increase in complexity of nano technologies, defects now become a competent comprising only part of the overall picture of yield, or more importantly, of revenue. Given the acceleration decrease in feature sizes, there is a corresponding shift from emphasis on random defectivity to both systematical defectivity as well as parametric integrity. With the view that yield loss should be generalized to revenue loss of any type, it can then be understood that the notion of process monitoring generalizes to not just defect count, but also to be broader set of characteristic including device parameters. In this regards, the tool set for monitoring the process needs to be generalized to also include systematic and parametric inspection system. The model is that an inspection tool plus an associated algorithm is required for monitoring the variance in all critical elements. The fab must then optimize the set of tools and algorithms. Including integrated metrology tools in this optimization generalizes the revenue model further, but adds significant revenue enhancement opportunities. The issue and tradeoffs imply that the fabs must consider the full characterization needs in order to determine the proper mix of monitoring tools and algorithms.

  14. Relationships of pinon juniper woodland expansion and climate trends in the Walker Basin, Nevada

    Science.gov (United States)

    Donald, Jonathon

    Landscapes are in constant flux. Vegetation distributions have changed in conjunction with climate, driven by factors such as Milankovitch cycles and atmospheric composition. Until recently, these changes have occurred gradually. Human populations are altering Earth's systems, including atmospheric composition and land use. This is altering vegetation distributions at landscape scales due to changes in species potential niche, as well as current and historical alteration of their realized niche. Vegetation shifts have the potential to be more pronounced in arid and mountainous environments as resources available to plants such as soil moisture are more limiting. In the Great Basin physiographic region of the western United States, woody encroachment of pinon juniper (Pinus monophylla & Juniperus osteosperma) woodlands is well known, but the drivers of its expansion are not well understood across elevational gradients. Predominant theories of future vegetation distribution change due to a changing climate, predict that montane species will move upslope in response to increasing temperatures. In pinon juniper woodlands, the focus has been on downslope movement of woodlands into other ecosystem types. The drivers for this are typically thought to be historical land uses such as grazing and fire exclusion. However, infilling and establishment is occurring throughout its distribution and relatively little attention has been paid to woodland movement uphill. This study focuses on two mountain ranges within the Walker Lake Basin, so as to understand changes occurring along the full gradient of pinon juniper woodlands, from lower to upper treeline, on both the western and eastern side of the ranges. The overall goal of this study was to understand trends of change (increasing, decreasing canopy density) in pinon juniper woodlands and determine if these trends were related to climate change trends. Trends in both vegetation and climate were analyzed for the entire

  15. Wet Little Ice Age in tropical Vietnam consistent with amplification of Pacific Walker Circulation

    Science.gov (United States)

    Stevens, Lora; Doiron, Kelsey

    2017-04-01

    Mean climate of tropical mainland SE Asia (MSEA) results from complex interactions of the ITCZ and related monsoon, Pacific Walker Circulation (PWC) and ENSO. Although millennial and centennial-scale climate variability for MSEA is most frequently attributed to variations in summer monsoon strength, MSEA is "sandwiched" between two monsoonal branches, the Indian summer monsoon and the East Asian monsoon, which may not behave synchronously. In addition to longer climatic trends, abrupt, short-lived droughts in MSEA have been linked to societal instability and food shortages. Specific triggers for, and spatial extent of, the droughts are not well understood. To explore causes and refine the spatial distribution of these droughts, as well as to place them within the mean climate state, a high-resolution oxygen-isotopic record of lacustrine carbonates was constructed from a sediment core from Ao Tiên (Fairy Pond), NW Vietnam (22° 26.9' N, 105° 37.03'E). Ao Tiên is a small sinkhole in the karst region of Bac Kạn Province. It is hydrologically connected via fractured limestone to a larger lake, Ba Be, and the Năng River. The lake is currently anoxic below 4 m depth, and the carbonate-rich sediment preserves alternating homogeneous and laminated sediment packets. We sampled the 1.3 m core in contiguous 5 mm increments for a record with 2-3 yr resolution. High/low isotopic values are interpreted as drier/wetter as a function of moisture balance (inputs minus evaporation) of the lake. Overall dry conditions prevailed during the period AD 1390-1520. A steady increase in effective moisture occurred from AD 1520 to 1645 with peak effective moisture from AD 1645 to 1750, during the heart of the Little Ice Age (LIA). This pattern of hydroclimate is consistent with records from the South China Sea and Indonesia, but opposite to speleothem records from Central China. Thus climatic shifts at Ao Tiên are not consistent with a simple weakening of the summer monsoon or

  16. Loops and autonomy promote evolvability of ecosystem networks.

    Science.gov (United States)

    Luo, Jianxi

    2014-09-29

    The structure of ecological networks, in particular food webs, determines their ability to evolve further, i.e. evolvability. The knowledge about how food web evolvability is determined by the structures of diverse ecological networks can guide human interventions purposefully to either promote or limit evolvability of ecosystems. However, the focus of prior food web studies was on stability and robustness; little is known regarding the impact of ecological network structures on their evolvability. To correlate ecosystem structure and evolvability, we adopt the NK model originally from evolutionary biology to generate and assess the ruggedness of fitness landscapes of a wide spectrum of model food webs with gradual variation in the amount of feeding loops and link density. The variation in network structures is controlled by linkage rewiring. Our results show that more feeding loops and lower trophic link density, i.e. higher autonomy of species, of food webs increase the potential for the ecosystem to generate heritable variations with improved fitness. Our findings allow the prediction of the evolvability of actual food webs according to their network structures, and provide guidance to enhancing or controlling the evolvability of specific ecosystems.

  17. Protein structural modularity and robustness are associated with evolvability.

    Science.gov (United States)

    Rorick, Mary M; Wagner, Günter P

    2011-01-01

    Theory suggests that biological modularity and robustness allow for maintenance of fitness under mutational change, and when this change is adaptive, for evolvability. Empirical demonstrations that these traits promote evolvability in nature remain scant however. This is in part because modularity, robustness, and evolvability are difficult to define and measure in real biological systems. Here, we address whether structural modularity and/or robustness confer evolvability at the level of proteins by looking for associations between indices of protein structural modularity, structural robustness, and evolvability. We propose a novel index for protein structural modularity: the number of regular secondary structure elements (helices and strands) divided by the number of residues in the structure. We index protein evolvability as the proportion of sites with evidence of being under positive selection multiplied by the average rate of adaptive evolution at these sites, and we measure this as an average over a phylogeny of 25 mammalian species. We use contact density as an index of protein designability, and thus, structural robustness. We find that protein evolvability is positively associated with structural modularity as well as structural robustness and that the effect of structural modularity on evolvability is independent of the structural robustness index. We interpret these associations to be the result of reduced constraints on amino acid substitutions in highly modular and robust protein structures, which results in faster adaptation through natural selection.

  18. A Perspective on the Evolving Landscape in Male Reproductive Medicine.

    Science.gov (United States)

    Bhasin, Shalender

    2016-03-01

    Men's health and aging are emerging as important areas of research opportunity because of advances in reproductive biology and the recognition of men's health as a unique and important aspect of public health. A perspective of the evolving landscape in male reproductive medicine. Remarkable discoveries in reproductive biology have greatly advanced the treatment of erectile dysfunction, androgen deficiency, infertility, hormone sensitive cancers, and prostate diseases. Although the off-label use of testosterone in middle-aged and older men has grown, the management of androgen deficiency syndromes remains suboptimal. There is a pressing need for wider adoption of accurate testosterone assays and harmonized reference ranges and large randomized trials of testosterone's efficacy and cardiovascular and prostate safety. The transformation in idealized body image towards greater muscularity has contributed to increasing prevalence of body image disorders and the use of muscle building drugs in men. Therapeutic options for fertility regulation in men remain limited, the pathophysiologic basis of infertility in a vast majority of infertile men remains unknown, and assisted reproductive technologies remain inaccessible to many infertile men. Much of the dogma on testosterone's binding to its binding proteins remains inaccurate, and the role of free and albumin-bound testosterone poorly understood. The reproductive health of cancer survivors and the availability of wider contraceptive choices for men are other areas of unmet need. Suboptimal care of transgender persons has framed transgender medicine as an important healthcare disparities issue. Transformative changes in societal attitudes towards men's sexual health, body image, and gender identity, and in the economics of reproductive healthcare services, offer extraordinary opportunities for translational science that is patient focused, mechanism based, and integrated with healthcare.

  19. Sub-Markov Random Walk for Image Segmentation.

    Science.gov (United States)

    Dong, Xingping; Shen, Jianbing; Shao, Ling; Van Gool, Luc

    2016-02-01

    A novel sub-Markov random walk (subRW) algorithm with label prior is proposed for seeded image segmentation, which can be interpreted as a traditional random walker on a graph with added auxiliary nodes. Under this explanation, we unify the proposed subRW and other popular random walk (RW) algorithms. This unifying view will make it possible for transferring intrinsic findings between different RW algorithms, and offer new ideas for designing novel RW algorithms by adding or changing auxiliary nodes. To verify the second benefit, we design a new subRW algorithm with label prior to solve the segmentation problem of objects with thin and elongated parts. The experimental results on both synthetic and natural images with twigs demonstrate that the proposed subRW method outperforms previous RW algorithms for seeded image segmentation.

  20. Biased and greedy random walks on two-dimensional lattices with quenched randomness: The greedy ant within a disordered environment

    Science.gov (United States)

    Mitran, T. L.; Melchert, O.; Hartmann, A. K.

    2013-12-01

    The main characteristics of biased greedy random walks (BGRWs) on two-dimensional lattices with real-valued quenched disorder on the lattice edges are studied. Here the disorder allows for negative edge weights. In previous studies, considering the negative-weight percolation (NWP) problem, this was shown to change the universality class of the existing, static percolation transition. In the presented study, four different types of BGRWs and an algorithm based on the ant colony optimization heuristic were considered. Regarding the BGRWs, the precise configurations of the lattice walks constructed during the numerical simulations were influenced by two parameters: a disorder parameter ρ that controls the amount of negative edge weights on the lattice and a bias strength B that governs the drift of the walkers along a certain lattice direction. The random walks are “greedy” in the sense that the local optimal choice of the walker is to preferentially traverse edges with a negative weight (associated with a net gain of “energy” for the walker). Here, the pivotal observable is the probability that, after termination, a lattice walk exhibits a total negative weight, which is here considered as percolating. The behavior of this observable as function of ρ for different bias strengths B is put under scrutiny. Upon tuning ρ, the probability to find such a feasible lattice walk increases from zero to 1. This is the key feature of the percolation transition in the NWP model. Here, we address the question how well the transition point ρc, resulting from numerically exact and “static” simulations in terms of the NWP model, can be resolved using simple dynamic algorithms that have only local information available, one of the basic questions in the physics of glassy systems.