WorldWideScience

Sample records for understanding irregular coevolutionary

  1. Venom Resistance as a Model for Understanding the Molecular Basis of Complex Coevolutionary Adaptations.

    Science.gov (United States)

    Holding, Matthew L; Drabeck, Danielle H; Jansa, Sharon A; Gibbs, H Lisle

    2016-11-01

    SynopsisVenom and venom resistance are molecular phenotypes widely considered to have diversified through coevolution between predators and prey. However, while evolutionary and functional studies on venom have been extensive, little is known about the molecular basis, variation, and complexity of venom resistance. We review known mechanisms of venom resistance and relate these mechanisms to their predicted impact on coevolutionary dynamics with venomous enemies. We then describe two conceptual approaches which can be used to examine venom/resistance systems. At the intraspecific level, tests of local adaptation in venom and resistance phenotypes can identify the functional mechanisms governing the outcomes of coevolution. At deeper evolutionary timescales, the combination of phylogenetically informed analyses of protein evolution coupled with studies of protein function promise to elucidate the mode and tempo of evolutionary change on potentially coevolving genes. We highlight case studies that use each approach to extend our knowledge of these systems as well as address larger questions about coevolutionary dynamics. We argue that resistance and venom are phenotypic traits which hold exceptional promise for investigating the mechanisms, dynamics, and outcomes of coevolution at the molecular level. Furthermore, extending the understanding of single gene-for-gene interactions to the whole resistance and venom phenotypes may provide a model system for examining the molecular and evolutionary dynamics of complex multi-gene interactions. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  2. Coevolutionary modeling in network formation

    KAUST Repository

    Al-Shyoukh, Ibrahim

    2014-12-03

    Network coevolution, the process of network topology evolution in feedback with dynamical processes over the network nodes, is a common feature of many engineered and natural networks. In such settings, the change in network topology occurs at a comparable time scale to nodal dynamics. Coevolutionary modeling offers the possibility to better understand how and why network structures emerge. For example, social networks can exhibit a variety of structures, ranging from almost uniform to scale-free degree distributions. While current models of network formation can reproduce these structures, coevolutionary modeling can offer a better understanding of the underlying dynamics. This paper presents an overview of recent work on coevolutionary models of network formation, with an emphasis on the following three settings: (i) dynamic flow of benefits and costs, (ii) transient link establishment costs, and (iii) latent preferential attachment.

  3. Coevolutionary modeling in network formation

    KAUST Repository

    Al-Shyoukh, Ibrahim; Chasparis, Georgios; Shamma, Jeff S.

    2014-01-01

    Network coevolution, the process of network topology evolution in feedback with dynamical processes over the network nodes, is a common feature of many engineered and natural networks. In such settings, the change in network topology occurs at a comparable time scale to nodal dynamics. Coevolutionary modeling offers the possibility to better understand how and why network structures emerge. For example, social networks can exhibit a variety of structures, ranging from almost uniform to scale-free degree distributions. While current models of network formation can reproduce these structures, coevolutionary modeling can offer a better understanding of the underlying dynamics. This paper presents an overview of recent work on coevolutionary models of network formation, with an emphasis on the following three settings: (i) dynamic flow of benefits and costs, (ii) transient link establishment costs, and (iii) latent preferential attachment.

  4. Understanding herding based on a co-evolutionary model for strategy and game structure

    International Nuclear Information System (INIS)

    Wang, Tao; Huang, Keke; Cheng, Yuan; Zheng, Xiaoping

    2015-01-01

    Highlights: •We model herding effect in emergency from perspective of evolutionary game theory. •Rational subpopulation survives only when the game parameter is significantly large. •Herding effect may arise if the relative rewarding for rational agents is small. •Increasing the relative rewarding for rational agents will prevent herding effect. •The evolution result is unstable if the game parameter approaches critical points. -- Abstract: So far, there has been no conclusion on the mechanism for herding, which is often discussed in the academia. Assuming escaping behavior of individuals in emergency is rational rather than out of panic according to recent findings in social psychology, we investigate the behavioral evolution of large crowds from the perspective of evolutionary game theory. Specifically, evolution of the whole population divided into two subpopulations, namely the co-evolution of strategy and game structure, is numerically simulated based on the game theoretical models built and the evolutionary rule designed, and a series of phenomena including extinction of one subpopulation and herding effect are predicted in the proposed framework. Furthermore, if the rewarding for rational agents becomes significantly larger than that for emotional ones, herding effect will disappear. It is exciting that some phase transition points with interesting properties for the system can be found. In addition, our model framework is able to explain the fact that it is difficult for mavericks to prevail in society. The current results of this work will be helpful in understanding and restraining herding effect in real life

  5. Coevolutionary ecological economics

    Energy Technology Data Exchange (ETDEWEB)

    Kallis, Giorgos [ICREA Researcher, ICTA, Universidad Autonoma de Barcelona, ETSE, QC/3095, 08193 Bellatera, Barcelona (Spain); Norgaard, Richard B. [Energy and Resources Group, University of California at Berkeley, 310 Barrows Hall, Berkeley, CA, 94720-3050 (United States)

    2010-02-15

    This paper maps a coevolutionary research agenda for ecological economics. At an epistemological level coevolution offers a powerful logic for transcending environmental and social determinisms and developing a cross-disciplinary approach in the study of socio-ecological systems. We identify four consistent stories emerging out of coevolutionary studies in ecological economics, concerning: environmental degradation and development failure in peripheral regions; the lock-in of unsustainable production-consumption patterns; the vicious cycle between human efforts to control undesirable micro-organisms and the evolution of these organisms; and the adaptive advantages of other-regarding, cooperative behaviors and institutions. We identify challenges in the conceptualization of coevolutionary relationships in relation to: the interaction between different hierarchical levels of evolution; the role of space and social power; uneven rates of change and crises. We conclude with the political implications of a coevolutionary perspective based on the premises of pragmatism. (author)

  6. Testing for coevolutionary diversification: linking pattern with process.

    Science.gov (United States)

    Althoff, David M; Segraves, Kari A; Johnson, Marc T J

    2014-02-01

    Coevolutionary diversification is cited as a major mechanism driving the evolution of diversity, particularly in plants and insects. However, tests of coevolutionary diversification have focused on elucidating macroevolutionary patterns rather than the processes giving rise to such patterns. Hence, there is weak evidence that coevolution promotes diversification. This is in part due to a lack of understanding about the mechanisms by which coevolution can cause speciation and the difficulty of integrating results across micro- and macroevolutionary scales. In this review, we highlight potential mechanisms of coevolutionary diversification, outline approaches to examine this process across temporal scales, and propose a set of minimal requirements for demonstrating coevolutionary diversification. Our aim is to stimulate research that tests more rigorously for coevolutionary diversification. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Coevolutionary aesthetics in human and biotic artworlds.

    Science.gov (United States)

    Prum, Richard O

    2013-01-01

    This work proposes a coevolutionary theory of aesthetics that encompasses both biotic and human arts. Anthropocentric perspectives in aesthetics prevent the recognition of the ontological complexity of the aesthetics of nature, and the aesthetic agency of many non-human organisms. The process of evaluative coevolution is shared by all biotic advertisements. I propose that art consists of a form of communication that coevolves with its own evaluation. Art and art history are population phenomena. I expand Arthur Danto's Artworld concept to any aesthetic population of producers and evaluators. Current concepts of art cannot exclusively circumscribe the human arts from many forms of non-human biotic art. Without assuming an arbitrarily anthropocentric perspective, any concept of art will need to engage with biodiversity, and either recognize many instances of biotic advertisements as art, or exclude some instances of human art. Coevolutionary aesthetic theory provides a heuristic account of aesthetic change in both human and biotic artworlds, including the coevolutionary origin of aesthetic properties and aesthetic value within artworlds. Restructuring aesthetics, art criticism, and art history without human beings at the organizing centers of these disciplines stimulate new progress in our understanding of art, and the unique human contributions to aesthetics and aesthetic diversity.

  8. Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

    International Nuclear Information System (INIS)

    Mahony, Jennifer; Ainsworth, Stuart; Stockdale, Stephen; Sinderen, Douwe van

    2012-01-01

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

  9. Phages of lactic acid bacteria: The role of genetics in understanding phage-host interactions and their co-evolutionary processes

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, Jennifer, E-mail: j.mahony@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Ainsworth, Stuart; Stockdale, Stephen [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Sinderen, Douwe van, E-mail: d.vansinderen@ucc.ie [Department of Microbiology, University College Cork, Western Road, Cork (Ireland); Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Western Road, Cork (Ireland)

    2012-12-20

    Dairy fermentations are among the oldest food processing applications, aimed at preservation and shelf-life extension through the use of lactic acid bacteria (LAB) starter cultures, in particular strains of Lactococcus lactis, Streptococcus thermophilus, Lactobacillus spp. and Leuconostoc spp. Traditionally this was performed by continuous passaging of undefined cultures from a finished fermentation to initiate the next fermentation. More recently, consumer demands on consistent and desired flavours and textures of dairy products have led to a more defined approach to such processes. Dairy (starter) companies have responded to the need to define the nature and complexity of the starter culture mixes, and dairy fermentations are now frequently based on defined starter cultures of low complexity, where each starter component imparts specific technological properties that are desirable to the product. Both mixed and defined starter culture approaches create the perfect environment for the proliferation of (bacterio)phages capable of infecting these LAB. The repeated use of the same starter cultures in a single plant, coupled to the drive towards higher and consistent production levels, increases the risk and negative impact of phage infection. In this review we will discuss recent advances in tracking the adaptation of phages to the dairy industry, the advances in understanding LAB phage-host interactions, including evolutionary and genomic aspects.

  10. Robust Traffic Flow Management: Coevolutionary Approach, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We will develop a Coevolutionary Decision Support Tool (CDST) that explicitly incorporates weather uncertainty (non-probabilistically) into strategic Traffic Flow...

  11. Public goods games on adaptive coevolutionary networks

    Science.gov (United States)

    Pichler, Elgar; Shapiro, Avi M.

    2017-07-01

    Productive societies feature high levels of cooperation and strong connections between individuals. Public Goods Games (PGGs) are frequently used to study the development of social connections and cooperative behavior in model societies. In such games, contributions to the public good are made only by cooperators, while all players, including defectors, reap public goods benefits, which are shares of the contributions amplified by a synergy factor. Classic results of game theory show that mutual defection, as opposed to cooperation, is the Nash Equilibrium of PGGs in well-mixed populations, where each player interacts with all others. In this paper, we explore the coevolutionary dynamics of a low information public goods game on a complex network in which players adapt to their environment in order to increase individual payoffs relative to past payoffs parameterized by greediness. Players adapt by changing their strategies, either to cooperate or to defect, and by altering their social connections. We find that even if players do not know other players' strategies and connectivity, cooperation can arise and persist despite large short-term fluctuations.

  12. Coevolutionary and genetic algorithm based building spatial and structural design

    NARCIS (Netherlands)

    Hofmeyer, H.; Davila Delgado, J.M.

    2015-01-01

    In this article, two methods to develop and optimize accompanying building spatial and structural designs are compared. The first, a coevolutionary method, applies deterministic procedures, inspired by realistic design processes, to cyclically add a suitable structural design to the input of a

  13. Irregular Applications: Architectures & Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Feo, John T.; Villa, Oreste; Tumeo, Antonino; Secchi, Simone

    2012-02-06

    Irregular applications are characterized by irregular data structures, control and communication patterns. Novel irregular high performance applications which deal with large data sets and require have recently appeared. Unfortunately, current high performance systems and software infrastructures executes irregular algorithms poorly. Only coordinated efforts by end user, area specialists and computer scientists that consider both the architecture and the software stack may be able to provide solutions to the challenges of modern irregular applications.

  14. Coevolutionary genetic variation in the legume-rhizobium transcriptome.

    Science.gov (United States)

    Heath, Katy D; Burke, Patricia V; Stinchcombe, John R

    2012-10-01

    Coevolutionary change requires reciprocal selection between interacting species, where the partner genotypes that are favoured in one species depend on the genetic composition of the interacting species. Coevolutionary genetic variation is manifested as genotype × genotype (G × G) interactions for fitness in interspecific interactions. Although quantitative genetic approaches have revealed abundant evidence for G × G interactions in symbioses, the molecular basis of this variation remains unclear. Here we study the molecular basis of G × G interactions in a model legume-rhizobium mutualism using gene expression microarrays. We find that, like quantitative traits such as fitness, variation in the symbiotic transcriptome may be partitioned into additive and interactive genetic components. Our results suggest that plant genetic variation had the largest influence on nodule gene expression and that plant genotype and the plant genotype × rhizobium genotype interaction determine global shifts in rhizobium gene expression that in turn feedback to influence plant fitness benefits. Moreover, the transcriptomic variation we uncover implicates regulatory changes in both species as drivers of symbiotic gene expression variation. Our study is the first to partition genetic variation in a symbiotic transcriptome and illuminates potential molecular routes of coevolutionary change. © 2012 Blackwell Publishing Ltd.

  15. Coevolutionary patterning of teeth and taste buds

    Science.gov (United States)

    Bloomquist, Ryan F.; Parnell, Nicholas F.; Phillips, Kristine A.; Fowler, Teresa E.; Yu, Tian Y.; Sharpe, Paul T.; Streelman, J. Todd

    2015-01-01

    Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium. PMID:26483492

  16. Coevolutionary patterning of teeth and taste buds.

    Science.gov (United States)

    Bloomquist, Ryan F; Parnell, Nicholas F; Phillips, Kristine A; Fowler, Teresa E; Yu, Tian Y; Sharpe, Paul T; Streelman, J Todd

    2015-11-03

    Teeth and taste buds are iteratively patterned structures that line the oro-pharynx of vertebrates. Biologists do not fully understand how teeth and taste buds develop from undifferentiated epithelium or how variation in organ density is regulated. These organs are typically studied independently because of their separate anatomical location in mammals: teeth on the jaw margin and taste buds on the tongue. However, in many aquatic animals like bony fishes, teeth and taste buds are colocalized one next to the other. Using genetic mapping in cichlid fishes, we identified shared loci controlling a positive correlation between tooth and taste bud densities. Genome intervals contained candidate genes expressed in tooth and taste bud fields. sfrp5 and bmper, notable for roles in Wingless (Wnt) and bone morphogenetic protein (BMP) signaling, were differentially expressed across cichlid species with divergent tooth and taste bud density, and were expressed in the development of both organs in mice. Synexpression analysis and chemical manipulation of Wnt, BMP, and Hedgehog (Hh) pathways suggest that a common cichlid oral lamina is competent to form teeth or taste buds. Wnt signaling couples tooth and taste bud density and BMP and Hh mediate distinct organ identity. Synthesizing data from fish and mouse, we suggest that the Wnt-BMP-Hh regulatory hierarchy that configures teeth and taste buds on mammalian jaws and tongues may be an evolutionary remnant inherited from ancestors wherein these organs were copatterned from common epithelium.

  17. Cyber Security Research Frameworks For Coevolutionary Network Defense

    Energy Technology Data Exchange (ETDEWEB)

    Rush, George D. [Missouri Univ. of Science and Technology, Rolla, MO (United States); Tauritz, Daniel Remy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-03

    Several architectures have been created for developing and testing systems used in network security, but most are meant to provide a platform for running cyber security experiments as opposed to automating experiment processes. In the first paper, we propose a framework termed Distributed Cyber Security Automation Framework for Experiments (DCAFE) that enables experiment automation and control in a distributed environment. Predictive analysis of adversaries is another thorny issue in cyber security. Game theory can be used to mathematically analyze adversary models, but its scalability limitations restrict its use. Computational game theory allows us to scale classical game theory to larger, more complex systems. In the second paper, we propose a framework termed Coevolutionary Agent-based Network Defense Lightweight Event System (CANDLES) that can coevolve attacker and defender agent strategies and capabilities and evaluate potential solutions with a custom network defense simulation. The third paper is a continuation of the CANDLES project in which we rewrote key parts of the framework. Attackers and defenders have been redesigned to evolve pure strategy, and a new network security simulation is devised which specifies network architecture and adds a temporal aspect. We also add a hill climber algorithm to evaluate the search space and justify the use of a coevolutionary algorithm.

  18. Star Formation in Irregular Galaxies.

    Science.gov (United States)

    Hunter, Deidre; Wolff, Sidney

    1985-01-01

    Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

  19. A Case Study of a Multiobjective Elitist Recombinative Genetic Algorithm with Coevolutionary Sharing

    NARCIS (Netherlands)

    Neef, R.M.; Thierens, D.; Arciszewski, H.F.R.

    1999-01-01

    We present a multiobjective genetic algorithm that incorporates various genetic algorithm techniques that have been proven to be efficient and robust in their problem domain. More specifically, we integrate rank based selection, adaptive niching through coevolutionary sharing, elitist recombination,

  20. A case study of a multiobjective recombinative genetic algorithm with coevolutionary sharing

    NARCIS (Netherlands)

    Neef, R.M.; Thierens, D.; Arciszewski, H.F.R.

    1999-01-01

    We present a multiobjective genetic algorithm that incorporates various genetic algorithm techniques that have been proven to be efficient and robust in their problem domain. More specifically, we integrate rank based selection, adaptive niching through coevolutionary sharing, elitist recombination,

  1. Perception-based Co-evolutionary Reinforcement Learning for UAV Sensor Allocation

    National Research Council Canada - National Science Library

    Berenji, Hamid

    2003-01-01

    .... A Perception-based reasoning approach based on co-evolutionary reinforcement learning was developed for jointly addressing sensor allocation on each individual UAV and allocation of a team of UAVs...

  2. A Multipopulation Coevolutionary Strategy for Multiobjective Immune Algorithm

    Directory of Open Access Journals (Sweden)

    Jiao Shi

    2014-01-01

    Full Text Available How to maintain the population diversity is an important issue in designing a multiobjective evolutionary algorithm. This paper presents an enhanced nondominated neighbor-based immune algorithm in which a multipopulation coevolutionary strategy is introduced for improving the population diversity. In the proposed algorithm, subpopulations evolve independently; thus the unique characteristics of each subpopulation can be effectively maintained, and the diversity of the entire population is effectively increased. Besides, the dynamic information of multiple subpopulations is obtained with the help of the designed cooperation operator which reflects a mutually beneficial relationship among subpopulations. Subpopulations gain the opportunity to exchange information, thereby expanding the search range of the entire population. Subpopulations make use of the reference experience from each other, thereby improving the efficiency of evolutionary search. Compared with several state-of-the-art multiobjective evolutionary algorithms on well-known and frequently used multiobjective and many-objective problems, the proposed algorithm achieves comparable results in terms of convergence, diversity metrics, and running time on most test problems.

  3. Epidemiological, evolutionary, and coevolutionary implications of context-dependent parasitism.

    Science.gov (United States)

    Vale, Pedro F; Wilson, Alastair J; Best, Alex; Boots, Mike; Little, Tom J

    2011-04-01

    Abstract Victims of infection are expected to suffer increasingly as parasite population growth increases. Yet, under some conditions, faster-growing parasites do not appear to cause more damage, and infections can be quite tolerable. We studied these conditions by assessing how the relationship between parasite population growth and host health is sensitive to environmental variation. In experimental infections of the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa, we show how easily an interaction can shift from a severe interaction, that is, when host fitness declines substantially with each unit of parasite growth, to a tolerable relationship by changing only simple environmental variables: temperature and food availability. We explored the evolutionary and epidemiological implications of such a shift by modeling pathogen evolution and disease spread under different levels of infection severity and found that environmental shifts that promote tolerance ultimately result in populations harboring more parasitized individuals. We also find that the opportunity for selection, as indicated by the variance around traits, varied considerably with the environmental treatment. Thus, our results suggest two mechanisms that could underlie coevolutionary hotspots and coldspots: spatial variation in tolerance and spatial variation in the opportunity for selection.

  4. Age structure and cooperation in coevolutionary games on dynamic network

    Science.gov (United States)

    Qin, Zilong; Hu, Zhenhua; Zhou, Xiaoping; Yi, Jingzhang

    2015-04-01

    Our proposed model imitates the growth of a population and describes the age structure and the level of cooperation in games on dynamic network with continuous changes of structure and topology. The removal of nodes and links caused by age-dependent attack, together with the nodes addition standing for the newborns of population, badly ruins Matthew effect in this coevolutionary process. Though the network is generated by growth and preferential attachment, it degenerates into random network and it is no longer heterogeneous. When the removal of nodes and links is equal to the addition of nodes and links, the size of dynamic network is maintained in steady-state, so is the low level of cooperation. Severe structure variation, homogeneous topology and continuous invasion of new defection jointly make dynamic network unsuitable for the survival of cooperator even when the probability with which the newborn players initially adopt the strategy cooperation is high, while things change slightly when the connections of newborn players are restricted. Fortunately, moderate interactions in a generation trigger an optimal recovering process to encourage cooperation. The model developed in this paper outlines an explanation of the cohesion changes in the development process of an organization. Some suggestions for cooperative behavior improvement are given in the end.

  5. A scalable coevolutionary multi-objective particle swarm optimizer

    Directory of Open Access Journals (Sweden)

    Xiangwei Zheng

    2010-11-01

    Full Text Available Multi-Objective Particle Swarm Optimizers (MOPSOs are easily trapped in local optima, cost more function evaluations and suffer from the curse of dimensionality. A scalable cooperative coevolution and ?-dominance based MOPSO (CEPSO is proposed to address these issues. In CEPSO, Multi-objective Optimization Problems (MOPs are decomposed in terms of their decision variables and are optimized by cooperative coevolutionary subswarms, and a uniform distribution mutation operator is adopted to avoid premature convergence. All subswarms share an external archive based on ?-dominance, which is also used as a leader set. Collaborators are selected from the archive and used to construct context vectors in order to evaluate particles in a subswarm. CEPSO is tested on several classical MOP benchmark functions and experimental results show that CEPSO can readily escape from local optima and optimize both low and high dimensional problems, but the number of function evaluations only increases linearly with respect to the number of decision variables. Therefore, CEPSO is competitive in solving various MOPs.

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

    LENUS (Irish Health Repository)

    Sen, Lin

    2011-06-03

    Abstract Background The chloroplast-localized ribulose-1, 5-biphosphate carboxylase\\/oxygenase (Rubisco), the primary enzyme responsible for autotrophy, is instrumental in the continual adaptation of plants to variations in the concentrations of CO2. The large subunit (LSU) of Rubisco is encoded by the chloroplast rbcL gene. Although adaptive processes have been previously identified at this gene, characterizing the relationships between the mutational dynamics at the protein level may yield clues on the biological meaning of such adaptive processes. The role of such coevolutionary dynamics in the continual fine-tuning of RbcL remains obscure. Results We used the timescale and phylogenetic analyses to investigate and search for processes of adaptive evolution in rbcL gene in three gymnosperm families, namely Podocarpaceae, Taxaceae and Cephalotaxaceae. To understand the relationships between regions identified as having evolved under adaptive evolution, we performed coevolutionary analyses using the software CAPS. Importantly, adaptive processes were identified at amino acid sites located on the contact regions among the Rubisco subunits and on the interface between Rubisco and its activase. Adaptive amino acid replacements at these regions may have optimized the holoenzyme activity. This hypothesis was pinpointed by evidence originated from our analysis of coevolution that supported the correlated evolution between Rubisco and its activase. Interestingly, the correlated adaptive processes between both these proteins have paralleled the geological variation history of the concentration of atmospheric CO2. Conclusions The gene rbcL has experienced bursts of adaptations in response to the changing concentration of CO2 in the atmosphere. These adaptations have emerged as a result of a continuous dynamic of mutations, many of which may have involved innovation of functional Rubisco features. Analysis of the protein structure and the functional implications of such

  7. Cry-wolf signals emerging from coevolutionary feedbacks in a tritrophic system

    Science.gov (United States)

    Yamauchi, Atsushi; van Baalen, Minus; Kobayashi, Yutaka; Takabayashi, Junji; Shiojiri, Kaori; Sabelis, Maurice W.

    2015-01-01

    For a communication system to be stable, senders should convey honest information. Providing dishonest information, however, can be advantageous to senders, which imposes a constraint on the evolution of communication systems. Beyond single populations and bitrophic systems, one may ask whether stable communication systems can evolve in multitrophic systems. Consider cross-species signalling where herbivore-induced plant volatiles (HIPVs) attract predators to reduce the damage from arthropod herbivores. Such plant signals may be honest and help predators to identify profitable prey/plant types via HIPV composition and to assess prey density via the amount of HIPVs. There could be selection for dishonest signals that attract predators for protection from possible future herbivory. Recently, we described a case in which plants release a fixed, high amount of HIPVs independent of herbivore load, adopting what we labelled a ‘cry-wolf’ strategy. To understand when such signals evolve, we model coevolutionary interactions between plants, herbivores and predators, and show that both ‘honest’ and ‘cry-wolf’ types can emerge, depending on the assumed plant–herbivore encounter rates and herbivore population density. It is suggested that the ‘cry-wolf’ strategy may have evolved to reduce the risk of heavy damage in the future. Our model suggests that eco-evolutionary feedback loops involving a third species may have important consequences for the stability of this outcome. PMID:26538597

  8. Connecting functional and statistical definitions of genotype by genotype interactions in coevolutionary studies

    Directory of Open Access Journals (Sweden)

    Katy Denise Heath

    2014-04-01

    Full Text Available Predicting how species interactions evolve requires that we understand the mechanistic basis of coevolution, and thus the functional genotype-by-genotype interactions (G × G that drive reciprocal natural selection. Theory on host-parasite coevolution provides testable hypotheses for empiricists, but depends upon models of functional G × G that remain loosely tethered to the molecular details of any particular system. In practice, reciprocal cross-infection studies are often used to partition the variation in infection or fitness in a population that is attributable to G × G (statistical G × G. Here we use simulations to demonstrate that within-population statistical G × G likely tells us little about the existence of coevolution, its strength, or the genetic basis of functional G × G. Combined with studies of multiple populations or points in time, mapping and molecular techniques can bridge the gap between natural variation and mechanistic models of coevolution, while model-based statistics can formally confront coevolutionary models with cross-infection data. Together these approaches provide a robust framework for inferring the infection genetics underlying statistical G × G, helping unravel the genetic basis of coevolution.

  9. Understanding the Unique Equatorial Density Irregularities

    Science.gov (United States)

    2015-04-01

    research, 55, 184-198, 2015. • Tesema, F., B. Damtie, M. Nigussie, The response of the ionosphere to intense geomagnetic storms in 2012 using GPS-TEC...Approved for public release; distribution is unlimited. fountain effect between 1000 to 1500 UT, which could be due to strong pre- reversal enhancement of...investigate different ionospheric phenomena such as the effect of the geomagnetic disturbance on the distribution of the low latitude ionospheric electron

  10. Understanding the sensory irregularities of esophageal disease.

    Science.gov (United States)

    Farmer, Adam D; Brock, Christina; Frøkjaer, Jens Brøndum; Gregersen, Hans; Khan, Sheeba; Lelic, Dina; Lottrup, Christian; Drewes, Asbjørn Mohr

    2016-08-01

    Symptoms relating to esophageal sensory abnormalities can be encountered in the clinical environment. Such sensory abnormalities may be present in demonstrable disease, such as erosive esophagitis, and in the ostensibly normal esophagus, such as non-erosive reflux disease or functional chest pain. In this review, the authors discuss esophageal sensation and the esophageal pain system. In addition, the authors provide a primer concerning the techniques that are available for investigating the autonomic nervous system, neuroimaging and neurophysiology of esophageal sensory function. Such technological advances, whilst not readily available in the clinic may facilitate the stratification and individualization of therapy in disorders of esophageal sensation in the future.

  11. Co-evolutionary dynamics of the human-environment system in the Heihe River basin in the past 2000years.

    Science.gov (United States)

    Lu, Zhixiang; Wei, Yongping; Feng, Qi; Xie, Jiali; Xiao, Honglang; Cheng, Guodong

    2018-09-01

    There is limited quantitative understanding of interactions between human and environmental systems over the millennial scale. We aim to reveal the co-evolutionary dynamics of the human-environment system in a river basin by simulating the water use and net primary production (NPP) allocation for human and environmental systems over the last 2000years in Heihe River basin (HRB) in northwest China. We partition the catchment total evapotranspiration (ET) into ET for human and environmental systems with a social-hydrological framework and estimate the NPP for human and environmental systems using the Box-Lieth model, then classify the co-evolutionary processes of the human-environment system into distinct phases using the rate of changes of NPP over time, and discover the trade-offs or synergies relationships between them based on the elasticity of change of the NPP for humans to the change of NPP for environment. The co-evolutionary dynamics of human-environment system in the HRB can be divided into four periods, including: Phase I (Han Dynasty-Yuan Dynasty): predevelopment characterized by nearly no trade-offs between human and environment; Phase II (Yuan Dynasty-RC): slow agricultural development: characterized by a small human win due to small trade-offs between human and environment; Phase III (RC-2000): rapid agricultural development: characterized by a large human win due to large trade-offs between human and environment, and Phase IV (2000-2010): a rebalance characterized by large human wins with a small-environment win due to synergies, although these occurred very occasionally. This study provides a quantitative approach to describe the co-evolution of the human-environment system from the perspective of trade-offs and synergies in the millennial scale for the first time. The relationships between humans and environment changed from trade-off to synergy with the implementation of the water reallocation scheme in 2000. These findings improve the

  12. Saturn's Irregular Moon Ymir

    Science.gov (United States)

    Denk, Tilmann; Mottola, S.

    2012-10-01

    Ymir (diameter 18 km), Saturn's second largest retrograde outer or irregular moon, has been observed six times by the Cassini narrow-angle camera (NAC) during the first 7 months in 2012. The observations span phase angles from 2° up to 102° and were taken at ranges between 15 and 18 million kilometers. From such a distance, Ymir is smaller than a pixel in the Cassini NAC. The data reveal a sidereal rotation period of 11.93 hrs, which is 1.6x longer than the previously reported value (Denk et al. 2011, EPSC/DPS #1452). Reason for this discrepancy is that the rotational light curve shows a rather uncommon 3-maxima and 3-minima shape at least in the phase angle range 50° to 100°, which was not recognizable in earlier data. The data cover several rotations from different viewing and illumination geometries and allow for a convex shape inversion with possibly a unique solution for the pole direction. The model reproduces the observed light curves to a very good accuracy without requiring albedo variegation, thereby suggesting that the lightcurve is dominated by the shape of Ymir. Among Saturn's irregular moons, the phenomenon of more than two maxima and minima at moderate to high phase angles is not unique to Ymir. At least Siarnaq and Paaliaq also show light curves with a strong deviation from a double-sine curve. Their rotation periods, however, remain unknown until more data can be taken. The light curve of Phoebe is fundamentally different to Ymir's because it is mainly shaped by local albedo differences and not by shape. Other reliable rotation periods of irregular satellites measured by Cassini include: Mundilfari 6.74 h; Kari 7.70 h; Albiorix 13.32 h; Kiviuq 21.82 h. More uncertain values are: Skathi 12 h; Bebhionn 16 h; Thrymr 27 h; Erriapus 28 h.

  13. Coevolutionary constraints in the sequence-space of macromolecular complexes reflect their self-assembly pathways.

    Science.gov (United States)

    Mallik, Saurav; Kundu, Sudip

    2017-07-01

    Is the order in which biomolecular subunits self-assemble into functional macromolecular complexes imprinted in their sequence-space? Here, we demonstrate that the temporal order of macromolecular complex self-assembly can be efficiently captured using the landscape of residue-level coevolutionary constraints. This predictive power of coevolutionary constraints is irrespective of the structural, functional, and phylogenetic classification of the complex and of the stoichiometry and quaternary arrangement of the constituent monomers. Combining this result with a number of structural attributes estimated from the crystal structure data, we find indications that stronger coevolutionary constraints at interfaces formed early in the assembly hierarchy probably promotes coordinated fixation of mutations that leads to high-affinity binding with higher surface area, increased surface complementarity and elevated number of molecular contacts, compared to those that form late in the assembly. Proteins 2017; 85:1183-1189. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Species co-evolutionary algorithm: a novel evolutionary algorithm based on the ecology and environments for optimization

    DEFF Research Database (Denmark)

    Li, Wuzhao; Wang, Lei; Cai, Xingjuan

    2015-01-01

    and affect each other in many ways. The relationships include competition, predation, parasitism, mutualism and pythogenesis. In this paper, we consider the five relationships between solutions to propose a co-evolutionary algorithm termed species co-evolutionary algorithm (SCEA). In SCEA, five operators...

  15. An Agent-Based Co-Evolutionary Multi-Objective Algorithm for Portfolio Optimization

    Directory of Open Access Journals (Sweden)

    Rafał Dreżewski

    2017-08-01

    Full Text Available Algorithms based on the process of natural evolution are widely used to solve multi-objective optimization problems. In this paper we propose the agent-based co-evolutionary algorithm for multi-objective portfolio optimization. The proposed technique is compared experimentally to the genetic algorithm, co-evolutionary algorithm and a more classical approach—the trend-following algorithm. During the experiments historical data from the Warsaw Stock Exchange is used in order to assess the performance of the compared algorithms. Finally, we draw some conclusions from these experiments, showing the strong and weak points of all the techniques.

  16. Irregular Migrants and the Law

    OpenAIRE

    Kassim, Azizah; Mat Zin, Ragayah Hj.

    2013-01-01

    This paper examines Malaysia`s policy on irregular migrants and its implementation, and discusses its impact. A survey and interview covering 404 respondents was conducted between July 2010 and June 2011 to ascertain the real situations surrounding irregular migrants in Malaysia, which is one of the major host countries of international migrants from developing nations. The policy on foreign workers was formulated in the mid-1980s to deal with the large number of irregular migrants and their ...

  17. Optimization of DP-M-QAM Transmitter using Cooperative Coevolutionary Genetic Algorithm

    DEFF Research Database (Denmark)

    Medeiros Diniz, Júlio César; Da Ros, Francesco; Porto da Silva, Edson

    2018-01-01

    We present a method for joint optimization of transmitter in-phase, quadrature and inter-polarization time skew, amplitude mismatch, and bias voltages. The method is based on a cooperative coevolutionary genetic algorithm with fitness functions extracted from a directly detected reference QAM sig...

  18. Phylogenetic framework for coevolutionary studies: a compass for exploring jungles of tangled trees.

    Science.gov (United States)

    Martínez-Aquino, Andrés

    2016-08-01

    Phylogenetics is used to detect past evolutionary events, from how species originated to how their ecological interactions with other species arose, which can mirror cophylogenetic patterns. Cophylogenetic reconstructions uncover past ecological relationships between taxa through inferred coevolutionary events on trees, for example, codivergence, duplication, host-switching, and loss. These events can be detected by cophylogenetic analyses based on nodes and the length and branching pattern of the phylogenetic trees of symbiotic associations, for example, host-parasite. In the past 2 decades, algorithms have been developed for cophylogetenic analyses and implemented in different software, for example, statistical congruence index and event-based methods. Based on the combination of these approaches, it is possible to integrate temporal information into cophylogenetical inference, such as estimates of lineage divergence times between 2 taxa, for example, hosts and parasites. Additionally, the advances in phylogenetic biogeography applying methods based on parametric process models and combined Bayesian approaches, can be useful for interpreting coevolutionary histories in a scenario of biogeographical area connectivity through time. This article briefly reviews the basics of parasitology and provides an overview of software packages in cophylogenetic methods. Thus, the objective here is to present a phylogenetic framework for coevolutionary studies, with special emphasis on groups of parasitic organisms. Researchers wishing to undertake phylogeny-based coevolutionary studies can use this review as a "compass" when "walking" through jungles of tangled phylogenetic trees.

  19. Process rather than pattern: finding pine needles in the coevolutionary haystack

    DEFF Research Database (Denmark)

    Nash, David R

    2008-01-01

    The geographic mosaic theory is fast becoming a unifying framework for coevolutionary studies. A recent experimental study of interactions between pines and mycorrhizal fungi in BMC Biology is the first to rigorously test geographical selection mosaics, one of the cornerstones of the theory....

  20. The bitterling–mussel coevolutionary relationship in areas of recent and ancient sympatry

    Czech Academy of Sciences Publication Activity Database

    Reichard, Martin; Polačik, Matej; Tarkan, A. S.; Spence, R.; Gaygusuz, Ö.; Ercan, E.; Ondračková, Markéta; Smith, C.

    2010-01-01

    Roč. 64, č. 10 (2010), s. 3047-3056 ISSN 0014-3820 R&D Projects: GA AV ČR KJB600930802 Institutional research plan: CEZ:AV0Z60930519 Keywords : coevolutionary arm races * evolutionary lag * gentes * host race * specialization * symbiosis Subject RIV: EG - Zoology Impact factor: 5.659, year: 2010

  1. Strategic Analysis of Irregular Warfare

    Science.gov (United States)

    2010-03-01

    the same mathematical equations used by Lanchester .10 Irregular Warfare Theory and Doctrine It is time to develop new analytical methods and models...basis on which to build, similar to what Lanchester provided almost 100 years ago. Figure 9 portrays both Lanchester’s approach and an irregular 17

  2. Irregular Dwarf Galaxy IC 1613

    Science.gov (United States)

    2005-01-01

    Ultraviolet image (left) and visual image (right) of the irregular dwarf galaxy IC 1613. Low surface brightness galaxies, such as IC 1613, are more easily detected in the ultraviolet because of the low background levels compared to visual wavelengths.

  3. Transdisciplinary Perspectives in Bioethics: A Co-evolutionary Introduction from the Big History

    Directory of Open Access Journals (Sweden)

    Javier Collado-Ruano

    2016-10-01

    Full Text Available The main objective of this work is to expand the bioethics notion expressed in the Article 17th of the Universal Declaration on Bioethics and Human Rights, concerning the interconnections between human beings and other life forms. For this purpose, it is combined the transdisciplinary methodology with the theoretical framework of the “Big History” to approach the co-evolutionary phenomena that life is developing on Earth for some 3.8 billion years. As a result, the study introduces us to the unification, integration and inclusion of the history of the universe, the solar system, Earth, and life with the history of human beings. In conclusion, I consider to safeguard the cosmic miracle that represents the emergence of life we must adopt new transdisciplinary perspectives into bioethics to address the ecosystem complexity of co-evolutionary processes of life on Gaia as a whole.

  4. Predicting protein folding rate change upon point mutation using residue-level coevolutionary information.

    Science.gov (United States)

    Mallik, Saurav; Das, Smita; Kundu, Sudip

    2016-01-01

    Change in folding kinetics of globular proteins upon point mutation is crucial to a wide spectrum of biological research, such as protein misfolding, toxicity, and aggregations. Here we seek to address whether residue-level coevolutionary information of globular proteins can be informative to folding rate changes upon point mutations. Generating residue-level coevolutionary networks of globular proteins, we analyze three parameters: relative coevolution order (rCEO), network density (ND), and characteristic path length (CPL). A point mutation is considered to be equivalent to a node deletion of this network and respective percentage changes in rCEO, ND, CPL are found linearly correlated (0.84, 0.73, and -0.61, respectively) with experimental folding rate changes. The three parameters predict the folding rate change upon a point mutation with 0.031, 0.045, and 0.059 standard errors, respectively. © 2015 Wiley Periodicals, Inc.

  5. Multi-step-prediction of chaotic time series based on co-evolutionary recurrent neural network

    International Nuclear Information System (INIS)

    Ma Qianli; Zheng Qilun; Peng Hong; Qin Jiangwei; Zhong Tanwei

    2008-01-01

    This paper proposes a co-evolutionary recurrent neural network (CERNN) for the multi-step-prediction of chaotic time series, it estimates the proper parameters of phase space reconstruction and optimizes the structure of recurrent neural networks by co-evolutionary strategy. The searching space was separated into two subspaces and the individuals are trained in a parallel computational procedure. It can dynamically combine the embedding method with the capability of recurrent neural network to incorporate past experience due to internal recurrence. The effectiveness of CERNN is evaluated by using three benchmark chaotic time series data sets: the Lorenz series, Mackey-Glass series and real-world sun spot series. The simulation results show that CERNN improves the performances of multi-step-prediction of chaotic time series

  6. Phylogeny of diving beetles reveals a coevolutionary arms race between the sexes.

    Directory of Open Access Journals (Sweden)

    Johannes Bergsten

    Full Text Available BACKGROUND: Darwin illustrated his sexual selection theory with male and female morphology of diving beetles, but maintained a cooperative view of their interaction. Present theory suggests that instead sexual conflict should be a widespread evolutionary force driving both intersexual coevolutionary arms races and speciation. METHODOLOGY/PRINCIPAL FINDINGS: We combined Bayesian phylogenetics, complete taxon sampling and a multi-gene approach to test the arms race scenario on a robust diving beetle phylogeny. As predicted, suction cups in males and modified dorsal surfaces in females showed a pronounced coevolutionary pattern. The female dorsal modifications impair the attachment ability of male suction cups, but each antagonistic novelty in females corresponds to counter-differentiation of suction cups in males. CONCLUSIONS: A recently diverged sibling species pair in Japan is possibly one consequence of this arms race and we suggest that future studies on hypoxia might reveal the key to the extraordinary selection for female counter-adaptations in diving beetles.

  7. Coevolutionary particle swarm optimization using Gaussian distribution for solving constrained optimization problems.

    Science.gov (United States)

    Krohling, Renato A; Coelho, Leandro dos Santos

    2006-12-01

    In this correspondence, an approach based on coevolutionary particle swarm optimization to solve constrained optimization problems formulated as min-max problems is presented. In standard or canonical particle swarm optimization (PSO), a uniform probability distribution is used to generate random numbers for the accelerating coefficients of the local and global terms. We propose a Gaussian probability distribution to generate the accelerating coefficients of PSO. Two populations of PSO using Gaussian distribution are used on the optimization algorithm that is tested on a suite of well-known benchmark constrained optimization problems. Results have been compared with the canonical PSO (constriction factor) and with a coevolutionary genetic algorithm. Simulation results show the suitability of the proposed algorithm in terms of effectiveness and robustness.

  8. GARCH and Irregularly Spaced Data

    NARCIS (Netherlands)

    Meddahi, N.; Renault, E.; Werker, B.J.M.

    2003-01-01

    An exact discretization of continuous time stochastic volatility processes observed at irregularly spaced times is used to give insights on how a coherent GARCH model can be specified for such data. The relation of our approach with those in the existing literature is studied.

  9. Transdisciplinary Perspectives in Bioethics: A Co-evolutionary Introduction from the Big History

    OpenAIRE

    Javier Collado-Ruano

    2016-01-01

    The main objective of this work is to expand the bioethics notion expressed in the Article 17th of the Universal Declaration on Bioethics and Human Rights, concerning the interconnections between human beings and other life forms. For this purpose, it is combined the transdisciplinary methodology with the theoretical framework of the “Big History” to approach the co-evolutionary phenomena that life is developing on Earth for some 3.8 billion years. As a result, the study introduces us to t...

  10. Ionospheric Irregularities at Mars Probed by MARSIS Topside Sounding

    Science.gov (United States)

    Harada, Y.; Gurnett, D. A.; Kopf, A. J.; Halekas, J. S.; Ruhunusiri, S.

    2018-01-01

    The upper ionosphere of Mars contains a variety of perturbations driven by solar wind forcing from above and upward propagating atmospheric waves from below. Here we explore the global distribution and variability of ionospheric irregularities around the exobase at Mars by analyzing topside sounding data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express. As irregular structure gives rise to off-vertical echoes with excess propagation time, the diffuseness of ionospheric echo traces can be used as a diagnostic tool for perturbed reflection surfaces. The observed properties of diffuse echoes above unmagnetized regions suggest that ionospheric irregularities with horizontal wavelengths of tens to hundreds of kilometers are particularly enhanced in the winter hemisphere and at high solar zenith angles. Given the known inverse dependence of neutral gravity wave amplitudes on the background atmospheric temperature, the ionospheric irregularities probed by MARSIS are most likely associated with plasma perturbations driven by atmospheric gravity waves. Though extreme events with unusually diffuse echoes are more frequently observed for high solar wind dynamic pressures during some time intervals, the vast majority of the diffuse echo events are unaffected by varying solar wind conditions, implying limited influence of solar wind forcing on the generation of ionospheric irregularities. Combination of remote and in situ measurements of ionospheric irregularities would offer the opportunity for a better understanding of the ionospheric dynamics at Mars.

  11. The co-evolutionary dynamics of directed network of spin market agents

    Science.gov (United States)

    Horváth, Denis; Kuscsik, Zoltán; Gmitra, Martin

    2006-09-01

    The spin market model [S. Bornholdt, Int. J. Mod. Phys. C 12 (2001) 667] is generalized by employing co-evolutionary principles, where strategies of the interacting and competitive traders are represented by local and global couplings between the nodes of dynamic directed stochastic network. The co-evolutionary principles are applied in the frame of Bak-Sneppen self-organized dynamics [P. Bak, K. Sneppen, Phys. Rev. Lett. 71 (1993) 4083] that includes the processes of selection and extinction actuated by the local (node) fitness. The local fitness is related to orientation of spin agent with respect to the instant magnetization. The stationary regime is formed due to the interplay of self-organization and adaptivity effects. The fat tailed distributions of log-price returns are identified numerically. The non-trivial model consequence is the evidence of the long time market memory indicated by the power-law range of the autocorrelation function of volatility with exponent smaller than one. The simulations yield network topology with broad-scale node degree distribution characterized by the range of exponents 1.3social networks.

  12. Success of cuckoo catfish brood parasitism reflects coevolutionary history and individual experience of their cichlid hosts

    Science.gov (United States)

    Polačik, Matej; Smith, Carl; Honza, Marcel; Reichard, Martin

    2018-01-01

    Obligate brood parasites manipulate other species into raising their offspring. Avian and insect brood parasitic systems demonstrate how interacting species engage in reciprocal coevolutionary arms races through behavioral and morphological adaptations and counteradaptations. Mouthbrooding cichlid fishes are renowned for their remarkable evolutionary radiations and complex behaviors. In Lake Tanganyika, mouthbrooding cichlids are exploited by the only obligate nonavian vertebrate brood parasite, the cuckoo catfish Synodontis multipunctatus. We show that coevolutionary history and individual learning both have a major impact on the success of cuckoo catfish parasitism between coevolved sympatric and evolutionarily naïve allopatric cichlid species. The rate of cuckoo catfish parasitism in coevolved Tanganyikan hosts was 3 to 11 times lower than in evolutionarily naïve cichlids. Moreover, using experimental infections, we demonstrate that parasite egg rejection in sympatric hosts was much higher, leading to seven times greater parasite survival in evolutionarily naïve than sympatric hosts. However, a high rejection frequency of parasitic catfish eggs by coevolved sympatric hosts came at a cost of increased rejection of their own eggs. A significant cost of catfish parasitism was universal, except for coevolved sympatric cichlid species with previous experience of catfish parasitism, demonstrating that learning and individual experience both contribute to a successful host response.

  13. Coevolutionary arms race versus host defense chase in a tropical herbivore-plant system.

    Science.gov (United States)

    Endara, María-José; Coley, Phyllis D; Ghabash, Gabrielle; Nicholls, James A; Dexter, Kyle G; Donoso, David A; Stone, Graham N; Pennington, R Toby; Kursar, Thomas A

    2017-09-05

    Coevolutionary models suggest that herbivores drive diversification and community composition in plants. For herbivores, many questions remain regarding how plant defenses shape host choice and community structure. We addressed these questions using the tree genus Inga and its lepidopteran herbivores in the Amazon. We constructed phylogenies for both plants and insects and quantified host associations and plant defenses. We found that similarity in herbivore assemblages between Inga species was correlated with similarity in defenses. There was no correlation with phylogeny, a result consistent with our observations that the expression of defenses in Inga is independent of phylogeny. Furthermore, host defensive traits explained 40% of herbivore community similarity. Analyses at finer taxonomic scales showed that different lepidopteran clades select hosts based on different defenses, suggesting taxon-specific histories of herbivore-host plant interactions. Finally, we compared the phylogeny and defenses of Inga to phylogenies for the major lepidopteran clades. We found that closely related herbivores fed on Inga with similar defenses rather than on closely related plants. Together, these results suggest that plant defenses might be more evolutionarily labile than the herbivore traits related to host association. Hence, there is an apparent asymmetry in the evolutionary interactions between Inga and its herbivores. Although plants may evolve under selection by herbivores, we hypothesize that herbivores may not show coevolutionary adaptations, but instead "chase" hosts based on the herbivore's own traits at the time that they encounter a new host, a pattern more consistent with resource tracking than with the arms race model of coevolution.

  14. A CO-EVOLUTIONARY PERSPECTIVE AND ITS APPLICATION TO THE THEORY OF ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Flavia Luciane Scherer

    2012-11-01

    Full Text Available This article pointed out the reasons and possibilities of co-evolutionary studies, requirements and problems to develop such studies, as well as discuss some of the central theoretical frameworks to the theory of organizations, from the perspective of coevolution (lewin and volberda , 1999. From this, we identify the possible links that can be established between different lenses of study, when integrated into a co-evolutionary study. Such links are drawn by taking the analysis of institutional theory (dimaggio and powell, 1991; meyer and rowan, 1991; scott, 1995, the transaction costs theory (williamson, 1981 and the theory of social relations in economic action (granovetter, 1992. Thus, it is expected to contribute to the discussion about the possibilities for greater integration in organizational studies, when calling attention to the importance of moving toward a more inclusive, taking into account the macro economic and social dynamics and their impact on the level the firm (in terms of effect size, identity, culture and learning processes and its inverse relationships - from the firm to the macro environment.

  15. Co-evolutionary interactions between host resistance and pathogen avirulence genes in rice-Magnaporthe oryzae pathosystem.

    Science.gov (United States)

    Singh, Pankaj Kumar; Ray, Soham; Thakur, Shallu; Rathour, Rajeev; Sharma, Vinay; Sharma, Tilak Raj

    2018-06-01

    Rice and Magnaporthe oryzae constitutes an ideal pathosystem for studying host-pathogen interaction in cereals crops. There are two alternative hypotheses, viz. Arms race and Trench warfare, which explain the co-evolutionary dynamics of hosts and pathogens which are under continuous confrontation. Arms race proposes that both R- and Avr- genes of host and pathogen, respectively, undergo positive selection. Alternatively, trench warfare suggests that either R- or Avr- gene in the pathosystem is under balanced selection intending to stabilize the genetic advantage gained over the opposition. Here, we made an attempt to test the above-stated hypotheses in rice-M. oryzae pathosystem at loci of three R-Avr gene pairs, Piz-t-AvrPiz-t, Pi54-AvrPi54 and Pita-AvrPita using allele mining approach. Allele mining is an efficient way to capture allelic variants existing in the population and to study the selective forces imposed on the variants during evolution. Results of nucleotide diversity, neutrality statistics and phylogenetic analyses reveal that Piz-t, Pi54 and AvrPita are diversified and under positive selection at their corresponding loci, while their counterparts, AvrPiz-t, AvrPi54 and Pita are conserved and under balancing selection, in nature. These results imply that rice-M. oryzae populations are engaged in a trench warfare at least at the three R/Avr loci studied. It is a maiden attempt to study the co-evolution of three R-Avr gene pairs in this pathosystem. Knowledge gained from this study will help in understanding the evolutionary dynamics of host-pathogen interaction in a better way and will also aid in developing new durable blast resistant rice varieties in future. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

    DEFF Research Database (Denmark)

    Larsen, Simon Tylsgaard; Andersen, Nis Korsgaard; Søgaard, Emil

    2014-01-01

    -off angles is found to be caused by a decrease of the receding contact angle, which in turn is caused by an increase of the triple phase contact line of the drops for those more irregular surfaces. To understand the observation, we propose to treat the microdrops as rigid bodies and apply a torque balance...

  17. Orbital and Collisional Evolution of the Irregular Satellites

    Science.gov (United States)

    Nesvorný, David; Alvarellos, Jose L. A.; Dones, Luke; Levison, Harold F.

    2003-07-01

    instabilities operating on longer time spans. The average orbits calculated from this experiment were then used to probe the collisional evolution of the irregular satellite systems. We found that (1) the large irregular moons must have collisionally eliminated many small irregular moons, thus shaping their population to the currently observed structures; (2) some dynamical families of satellites could have been formed by catastrophic collisions among the irregular moons; and (3) Phoebe's surface must have been heavily cratered by impacts from an extinct population of Saturnian irregular moons, much larger than the present one. We therefore suggest that the Cassini imaging of Phoebe in 2004 can be used to determine the primordial population of small irregular moons of Saturn. In such a case, we will also better understand the overall efficiency of the formation process of the irregular satellites and the physical conditions that existed during planetary formation. We discovered two dynamical families of tightly clustered orbits within the Jovian retrograde group. We believe that these two clusters may be the remnants of two collisionally disrupted bodies. We found that the entire Jovian retrograde group and the Saturnian inclination groups were not produced by single breakups, because the ejection velocities derived from the orbital structures of these groups greatly exceed values calculated by modern numerical models of collisional breakups. Taken together, the evidence presented here suggests that many properties of the irregular moons previously assigned to their formation process may have resulted from their later dynamical and collisional evolution. Finally, we have found that several irregular moons, namely, Pasiphae, Sinope, S/2001 J10, S/2000 S5, S/2000 S6, and S/2000 S3, have orbits characterized by secular resonances. The orbits of some of these moons apparently evolved by some slow dissipative process in the past and became captured in tiny resonant volumes.

  18. Complex coevolutionary history of symbiotic Bacteroidales bacteria of various protists in the gut of termites

    Science.gov (United States)

    Noda, Satoko; Hongoh, Yuichi; Sato, Tomoyuki; Ohkuma, Moriya

    2009-01-01

    Background The microbial community in the gut of termites is responsible for the efficient decomposition of recalcitrant lignocellulose. Prominent features of this community are its complexity and the associations of prokaryotes with the cells of cellulolytic flagellated protists. Bacteria in the order Bacteroidales are involved in associations with a wide variety of gut protist species as either intracellular endosymbionts or surface-attached ectosymbionts. In particular, ectosymbionts exhibit distinct morphological patterns of the associations. Therefore, these Bacteroidales symbionts provide an opportunity to investigate not only the coevolutionary relationships with the host protists and their morphological evolution but also how symbiotic associations between prokaryotes and eukaryotes occur and evolve within a complex symbiotic community. Results Molecular phylogeny of 31 taxa of Bacteroidales symbionts from 17 protist genera in 10 families was examined based on 16S rRNA gene sequences. Their localization, morphology, and specificity were also examined by fluorescent in situ hybridizations. Although a monophyletic grouping of the ectosymbionts occurred in three related protist families, the symbionts of different protist genera were usually dispersed among several phylogenetic clusters unique to termite-gut bacteria. Similar morphologies of the associations occurred in multiple lineages of the symbionts. Nevertheless, the symbionts of congeneric protist species were closely related to one another, and in most cases, each host species harbored a unique Bacteroidales species. The endosymbionts were distantly related to the ectosymbionts examined so far. Conclusion The coevolutionary history of gut protists and their associated Bacteroidales symbionts is complex. We suggest multiple independent acquisitions of the Bacteroidales symbionts by different protist genera from a pool of diverse bacteria in the gut community. In this sense, the gut could serve as a

  19. Irregular Migration in Jordan, 1995-2007

    OpenAIRE

    AROURI, Fathi A.

    2008-01-01

    Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) This paper tackles the question of irregular migration in Jordan through its four main aspects. The first concerns irregular labour migrants and has been approached by using figures showing the socio-economic profile of non Jordanians working in Jordan and, additionally, unemployment in Jordan. This is done by assuming close similarities between legal and irregular labour migrants. The second is an attemp...

  20. Criticality predicts maximum irregularity in recurrent networks of excitatory nodes.

    Directory of Open Access Journals (Sweden)

    Yahya Karimipanah

    Full Text Available A rigorous understanding of brain dynamics and function requires a conceptual bridge between multiple levels of organization, including neural spiking and network-level population activity. Mounting evidence suggests that neural networks of cerebral cortex operate at a critical regime, which is defined as a transition point between two phases of short lasting and chaotic activity. However, despite the fact that criticality brings about certain functional advantages for information processing, its supporting evidence is still far from conclusive, as it has been mostly based on power law scaling of size and durations of cascades of activity. Moreover, to what degree such hypothesis could explain some fundamental features of neural activity is still largely unknown. One of the most prevalent features of cortical activity in vivo is known to be spike irregularity of spike trains, which is measured in terms of the coefficient of variation (CV larger than one. Here, using a minimal computational model of excitatory nodes, we show that irregular spiking (CV > 1 naturally emerges in a recurrent network operating at criticality. More importantly, we show that even at the presence of other sources of spike irregularity, being at criticality maximizes the mean coefficient of variation of neurons, thereby maximizing their spike irregularity. Furthermore, we also show that such a maximized irregularity results in maximum correlation between neuronal firing rates and their corresponding spike irregularity (measured in terms of CV. On the one hand, using a model in the universality class of directed percolation, we propose new hallmarks of criticality at single-unit level, which could be applicable to any network of excitable nodes. On the other hand, given the controversy of the neural criticality hypothesis, we discuss the limitation of this approach to neural systems and to what degree they support the criticality hypothesis in real neural networks. Finally

  1. Distributed parallel cooperative coevolutionary multi-objective large-scale immune algorithm for deployment of wireless sensor networks

    DEFF Research Database (Denmark)

    Cao, Bin; Zhao, Jianwei; Yang, Po

    2018-01-01

    -objective evolutionary algorithms the Cooperative Coevolutionary Generalized Differential Evolution 3, the Cooperative Multi-objective Differential Evolution and the Nondominated Sorting Genetic Algorithm III, the proposed algorithm addresses the deployment optimization problem efficiently and effectively.......Using immune algorithms is generally a time-intensive process especially for problems with a large number of variables. In this paper, we propose a distributed parallel cooperative coevolutionary multi-objective large-scale immune algorithm that is implemented using the message passing interface...... (MPI). The proposed algorithm is composed of three layers: objective, group and individual layers. First, for each objective in the multi-objective problem to be addressed, a subpopulation is used for optimization, and an archive population is used to optimize all the objectives. Second, the large...

  2. Ethical issues in irregular migration research

    NARCIS (Netherlands)

    Duvell, F.; Triandafyllidou, A.; Vollmer, B.

    2008-01-01

    This paper is concerned with the ethical issues arising for researchers engaged in the study of irregular migration. Irregular migration is by definition an elusive phenomenon as it takes place in violation of the law and at the margins of society. This very nature of the phenomenon raises important

  3. The Riddle of a Human Being: A Human Singularity of Co-evolutionary Processes

    Directory of Open Access Journals (Sweden)

    Helena N. Knyazeva

    2008-10-01

    Full Text Available span style="font-size: 10pt; font-family: #39;Times New Roman#39;"The theory of self-organization of complex systems studies laws of sustainable co-evolutionary development of structures having different speeds of development as well as laws of assembling of a complex evolutionary whole from parts when some elements of ldquo;memoryrdquo; (the biological memory, i.e. DNA, the memory of culture, i.e. the cultural and historical traditions, etc. must be included. The theory reveals general rules of nonlinear synthesis of complex evolutionary structures. The most important and paradoxical consequences of the holistic view, including an approach to solving the riddle of human personality, are as follows: 1 the explanation why and under what conditions a part (a human can be more complex than a whole (society; 2 in order to reconstruct society it is necessary to change an individual but not by cutting off the supposed undesirable past, since a human being as a microcosm is the synthesis of all previous stages of evolution, and as a result of repression of, it would seem, the wild past one can extinguish a ldquo;divine sparkrdquo; in his soul; 3 in the physical sense, singularity denotes a moment of instability, phase transition; one can talk about the human singularity of co-evolutionary processes, since in such a moment of instability individual actions of a human can play a key role in determining a channel of further development as well as in appearance of a new pattern of collective behavior in society; 4 as the models of nonlinear dynamics, elaborated at the Keldysh Institute of Applied Mathematics of the Russian Academy of Sciences in Moscow, show, there is a possibility of a direct influence of the future and even a touch of an infinitely remote future in certain evolutionary regimes and under rigorously definite conditions, more over, it turns out that such a possibility exists only for a human (admittedly, through a specific state of being

  4. Signatures of co-evolutionary host-pathogen interactions in the genome of the entomopathogenic nematode Steinernema carpocapsae.

    Science.gov (United States)

    Flores-Ponce, Mitzi; Vallebueno-Estrada, Miguel; González-Orozco, Eduardo; Ramos-Aboites, Hilda E; García-Chávez, J Noé; Simões, Nelson; Montiel, Rafael

    2017-04-26

    The entomopathogenic nematode Steinernema carpocapsae has been used worldwide as a biocontrol agent for insect pests, making it an interesting model for understanding parasite-host interactions. Two models propose that these interactions are co-evolutionary processes in such a way that equilibrium is never reached. In one model, known as "arms race", new alleles in relevant genes are fixed in both host and pathogens by directional positive selection, producing recurrent and alternating selective sweeps. In the other model, known as"trench warfare", persistent dynamic fluctuations in allele frequencies are sustained by balancing selection. There are some examples of genes evolving according to both models, however, it is not clear to what extent these interactions might alter genome-level evolutionary patterns and intraspecific diversity. Here we investigate some of these aspects by studying genomic variation in S. carpocapsae and other pathogenic and free-living nematodes from phylogenetic clades IV and V. To look for signatures of an arms-race dynamic, we conducted massive scans to detect directional positive selection in interspecific data. In free-living nematodes, we detected a significantly higher proportion of genes with sites under positive selection than in parasitic nematodes. However, in these genes, we found more enriched Gene Ontology terms in parasites. To detect possible effects of dynamic polymorphisms interactions we looked for signatures of balancing selection in intraspecific genomic data. The observed distribution of Tajima's D values in S. carpocapsae was more skewed to positive values and significantly different from the observed distribution in the free-living Caenorhabditis briggsae. Also, the proportion of significant positive values of Tajima's D was elevated in genes that were differentially expressed after induction with insect tissues as compared to both non-differentially expressed genes and the global scan. Our study provides a first

  5. A further analysis of the role of heterogeneity in coevolutionary spatial games

    Science.gov (United States)

    Cardinot, Marcos; Griffith, Josephine; O'Riordan, Colm

    2018-03-01

    Heterogeneity has been studied as one of the most common explanations of the puzzle of cooperation in social dilemmas. A large number of papers have been published discussing the effects of increasing heterogeneity in structured populations of agents, where it has been established that heterogeneity may favour cooperative behaviour if it supports agents to locally coordinate their strategies. In this paper, assuming an existing model of a heterogeneous weighted network, we aim to further this analysis by exploring the relationship (if any) between heterogeneity and cooperation. We adopt a weighted network which is fully populated by agents playing both the Prisoner's Dilemma or the Optional Prisoner's Dilemma games with coevolutionary rules, i.e., not only the strategies but also the link weights evolve over time. Surprisingly, results show that the heterogeneity of link weights (states) on their own does not always promote cooperation; rather cooperation is actually favoured by the increase in the number of overlapping states and not by the heterogeneity itself. We believe that these results can guide further research towards a more accurate analysis of the role of heterogeneity in social dilemmas.

  6. Epidemiological, evolutionary and co-evolutionary implications of context-dependent parasitism

    Science.gov (United States)

    Vale, Pedro F.; Wilson, Alastair J.; Best, Alex; Boots, Mike; Little, Tom J.

    2013-01-01

    Victims of infection are expected to suffer increasingly as parasite population growth increases. Yet, under some conditions, faster growing parasites do not appear to cause more damage and infections can be quite tolerable. We studied these conditions by assessing how the relationship between parasite population growth and host health is sensitive to environmental variation. In experimental infections of the crustacean Daphnia magna and its bacterial parasite Pasteuria ramosa we show how easily an interaction can shift from a severe interaction, i.e. when host fitness declines substantially with each unit of parasite growth, to a tolerable relationship by changing only simple environmental variables: temperature and food availability. We explored the evolutionary and epidemiological implications of such a shift by modelling pathogen evolution and disease spread under different levels of infection severity, and find that environmental shifts that promote tolerance ultimately result in populations harbouring more parasitized individuals. We also find that the opportunity for selection, as indicated by the variance around traits, varied considerably with the environmental treatment. Thus our results suggest two mechanisms that could underlie co-evolutionary hot- and coldspots: spatial variation in tolerance and spatial variation in the opportunity for selection. PMID:21460572

  7. Reciprocal selection causes a coevolutionary arms race between crossbills and lodgepole pine.

    Science.gov (United States)

    Benkman, Craig W; Parchman, Thomas L; Favis, Amanda; Siepielski, Adam M

    2003-08-01

    Few studies have shown both reciprocal selection and reciprocal adaptations for a coevolving system in the wild. The goal of our study was to determine whether the patterns of selection on Rocky Mountain lodgepole pine (Pinus contorta spp. latifolia) and red crossbills (Loxia curvirostra complex) were concordant with earlier published evidence of reciprocal adaptations in lodgepole pine and crossbills on isolated mountain ranges in the absence of red squirrels (Tamiasciurus hudsonicus). We found that selection (directional) by crossbills on lodgepole pine where Tamiasciurus are absent was divergent from the selection (directional) exerted by Tamiasciurus on lodgepole pine. This resulted in divergent selection between areas with and without Tamiasciurus that was congruent with the geographic patterns of cone variation. In the South Hills, Idaho, where Tamiasciurus are absent and red crossbills are thought to be coevolving with lodgepole pine, crossbills experienced stabilizing selection on bill size, with cone structure as the agent of selection. These results show that crossbills and lodgepole pine exhibit reciprocal adaptations in response to reciprocal selection, and they provide insight into the traits mediating and responding to selection in a coevolutionary arms race.

  8. Ship Pipe Routing Design Using NSGA-II and Coevolutionary Algorithm

    Directory of Open Access Journals (Sweden)

    Wentie Niu

    2016-01-01

    Full Text Available Pipe route design plays a prominent role in ship design. Due to the complex configuration in layout space with numerous pipelines, diverse design constraints, and obstacles, it is a complicated and time-consuming process to obtain the optimal route of ship pipes. In this article, an optimized design method for branch pipe routing is proposed to improve design efficiency and to reduce human errors. By simplifying equipment and ship hull models and dividing workspace into three-dimensional grid cells, the mathematic model of layout space is constructed. Based on the proposed concept of pipe grading method, the optimization model of pipe routing is established. Then an optimization procedure is presented to deal with pipe route planning problem by combining maze algorithm (MA, nondominated sorting genetic algorithm II (NSGA-II, and cooperative coevolutionary nondominated sorting genetic algorithm II (CCNSGA-II. To improve the performance in genetic algorithm procedure, a fixed-length encoding method is presented based on improved maze algorithm and adaptive region strategy. Fuzzy set theory is employed to extract the best compromise pipeline from Pareto optimal solutions. Simulation test of branch pipe and design optimization of a fuel piping system were carried out to illustrate the design optimization procedure in detail and to verify the feasibility and effectiveness of the proposed methodology.

  9. Developing pathways for energy storage in the UK using a coevolutionary framework

    International Nuclear Information System (INIS)

    Taylor, Peter G.; Bolton, Ronan; Stone, Dave; Upham, Paul

    2013-01-01

    A number of recent techno-economic studies have shown that energy storage could offer significant benefits to a low-carbon UK energy system as it faces increased challenges in matching supply and demand. However, the majority of this work has not investigated the real-world issues affecting the widespread deployment of storage. This paper is designed to address this gap by drawing on the systems innovation and socio-technical transitions literature to identify some of the most important contextual factors which are likely to influence storage deployment. Specifically it uses a coevolutionary framework to examine how changes in ecosystems, user practices, business strategies, institutions and technologies are creating a new selection environment and potentially opening up the energy system to new variations of storage for both electricity and heat. The analysis shows how these different dimensions of the energy regime can coevolve in mutually reinforcing ways to create alternative pathways for the energy system which in turn have different flexibility requirements and imply different roles for storage technologies. Using this framework three pathways are developed – user led, decentralised and centralised – which illustrate potential long-term trajectories for energy storage technologies in a low-carbon energy system. - highlights: • Energy storage can play a significant role in a low carbon UK energy system. • Changes in the selection environment will impact its deployment. • Several different deployment pathways are possible. • Its precise role is still subject to considerable uncertainty

  10. Escalation of a coevolutionary arms race through host rejection of brood parasitic young.

    Science.gov (United States)

    Langmore, Naomi E; Hunt, Sarah; Kilner, Rebecca M

    2003-03-13

    Cuckoo nestlings that evict all other young from the nest soon after hatching impose a high reproductive cost on their hosts. In defence, hosts have coevolved strategies to prevent brood parasitism. Puzzlingly, they do not extend beyond the egg stage. Thus, hosts adept at recognizing foreign eggs remain vulnerable to exploitation by cuckoo nestlings. Here we show that the breach of host egg defences by cuckoos creates a new stage in the coevolutionary cycle. We found that defences used during the egg-laying period by host superb fairy-wrens (Malurus cyaneus) are easily evaded by the Horsfield's bronze-cuckoo (Chrysococcyx basalis), a specialist fairy-wren brood parasite. However, although hosts never deserted their own broods, they later abandoned 40% of nests containing a lone Horsfield's bronze-cuckoo nestling, and 100% of nests with a lone shining bronze-cuckoo nestling (Chrysococcyx lucidus), an occasional fairy-wren brood parasite. Our experiments demonstrate that host discrimination against evictor-cuckoo nestlings is possible, and suggest that it has selected for the evolution of nestling mimicry in bronze-cuckoos.

  11. Vibration-Based Damage Detection in Beams by Cooperative Coevolutionary Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Kittipong Boonlong

    2014-03-01

    Full Text Available Vibration-based damage detection, a nondestructive method, is based on the fact that vibration characteristics such as natural frequencies and mode shapes of structures are changed when the damage happens. This paper presents cooperative coevolutionary genetic algorithm (CCGA, which is capable for an optimization problem with a large number of decision variables, as the optimizer for the vibration-based damage detection in beams. In the CCGA, a minimized objective function is a numerical indicator of differences between vibration characteristics of the actual damage and those of the anticipated damage. The damage detection in a uniform cross-section cantilever beam, a uniform strength cantilever beam, and a uniform cross-section simply supported beam is used as the test problems. Random noise in the vibration characteristics is also considered in the damage detection. In the simulation analysis, the CCGA provides the superior solutions to those that use standard genetic algorithms presented in previous works, although it uses less numbers of the generated solutions in solution search. The simulation results reveal that the CCGA can efficiently identify the occurred damage in beams for all test problems including the damage detection in a beam with a large number of divided elements such as 300 elements.

  12. Capture of irregular satellites at Jupiter

    International Nuclear Information System (INIS)

    Nesvorný, David; Vokrouhlický, David; Deienno, Rogerio

    2014-01-01

    The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early solar system instability when encounters between the outer planets occurred. Nesvorný et al. already showed that the irregular satellites of Saturn, Uranus, and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encounters with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary disk is found to be (1.3-3.6) × 10 –8 . This is roughly enough to explain the observed population of jovian irregular moons. We also confirm Nesvorný et al.'s results for the irregular satellites of Saturn, Uranus, and Neptune.

  13. Significance of scatter radar studies of E and F region irregularities at high latitudes

    International Nuclear Information System (INIS)

    Greenwald, R.A.

    1983-01-01

    This chapter considers the mechanisms by which electron density irregularities may be generated in the high latitude ionosphere and the techniques through which they are observed with ground base radars. The capabilities of radars used for studying these irregularities are compared with the capabilities of radars used for incoherent scatter measurements. The use of irregularity scatter techniques for dynamic studies of larger scale structured phenomena is discussed. Topics considered include E-region irregularities, observations with auroral radars, plasma drifts associated with a westward travelling surge, and ionospheric plasma motions associated with resonant waves. It is shown why high latitude F-region irregularity studies must be made in the HF frequency band (3-30 MHz). The joint use of the European Incoherent Scatter Association (EISCAT), STARE and SAFARI facilities is examined, and it is concluded that the various techniques will enhance each other and provide a better understanding of the various processes being studied

  14. Examining U.S. Irregular Warfare Doctrine

    National Research Council Canada - National Science Library

    Kimbrough, IV, James M

    2008-01-01

    ... of insurgency and terrorism. In response to the associated strategic challenges, a growing debate occurred among military historians, strategists, and leaders about the proper principles necessary for contemporary irregular...

  15. Sequence co-evolutionary information is a natural partner to minimally-frustrated models of biomolecular dynamics [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Jeffrey K Noel

    2016-01-01

    Full Text Available Experimentally derived structural constraints have been crucial to the implementation of computational models of biomolecular dynamics. For example, not only does crystallography provide essential starting points for molecular simulations but also high-resolution structures permit for parameterization of simplified models. Since the energy landscapes for proteins and other biomolecules have been shown to be minimally frustrated and therefore funneled, these structure-based models have played a major role in understanding the mechanisms governing folding and many functions of these systems. Structural information, however, may be limited in many interesting cases. Recently, the statistical analysis of residue co-evolution in families of protein sequences has provided a complementary method of discovering residue-residue contact interactions involved in functional configurations. These functional configurations are often transient and difficult to capture experimentally. Thus, co-evolutionary information can be merged with that available for experimentally characterized low free-energy structures, in order to more fully capture the true underlying biomolecular energy landscape.

  16. Locating irregularly shaped clusters of infection intensity

    Directory of Open Access Journals (Sweden)

    Niko Yiannakoulias

    2010-05-01

    Full Text Available Patterns of disease may take on irregular geographic shapes, especially when features of the physical environment influence risk. Identifying these patterns can be important for planning, and also identifying new environmental or social factors associated with high or low risk of illness. Until recently, cluster detection methods were limited in their ability to detect irregular spatial patterns, and limited to finding clusters that were roughly circular in shape. This approach has less power to detect irregularly-shaped, yet important spatial anomalies, particularly at high spatial resolutions. We employ a new method of finding irregularly-shaped spatial clusters at micro-geographical scales using both simulated and real data on Schistosoma mansoni and hookworm infection intensities. This method, which we refer to as the “greedy growth scan”, is a modification of the spatial scan method for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the “greedy growth scan” is a suitable method for exploratory geographical analysis of infection intensity data when irregular shapes are suspected, especially at micro-geographical scales.

  17. Detecting chaos in irregularly sampled time series.

    Science.gov (United States)

    Kulp, C W

    2013-09-01

    Recently, Wiebe and Virgin [Chaos 22, 013136 (2012)] developed an algorithm which detects chaos by analyzing a time series' power spectrum which is computed using the Discrete Fourier Transform (DFT). Their algorithm, like other time series characterization algorithms, requires that the time series be regularly sampled. Real-world data, however, are often irregularly sampled, thus, making the detection of chaotic behavior difficult or impossible with those methods. In this paper, a characterization algorithm is presented, which effectively detects chaos in irregularly sampled time series. The work presented here is a modification of Wiebe and Virgin's algorithm and uses the Lomb-Scargle Periodogram (LSP) to compute a series' power spectrum instead of the DFT. The DFT is not appropriate for irregularly sampled time series. However, the LSP is capable of computing the frequency content of irregularly sampled data. Furthermore, a new method of analyzing the power spectrum is developed, which can be useful for differentiating between chaotic and non-chaotic behavior. The new characterization algorithm is successfully applied to irregularly sampled data generated by a model as well as data consisting of observations of variable stars.

  18. Approaches to understanding the impact of life-history features on plant-pathogen co-evolutionary dynamics

    Science.gov (United States)

    Jeremy J. Burdon; Peter H. Thrall; Adnane Nemri

    2012-01-01

    Natural plant-pathogen associations are complex interactions in which the interplay of environment, host, and pathogen factors results in spatially heterogeneous ecological and epidemiological dynamics. The evolutionary patterns that result from the interaction of these factors are still relatively poorly understood. Recently, integration of the appropriate spatial and...

  19. Irregular menstruation according to occupational status.

    Science.gov (United States)

    Kwak, Yeunhee; Kim, Yoonjung

    2017-07-06

    This cross-sectional study explored associations of irregular menstruation with occupational characteristics, using secondary analyses of data from 4,731 women aged 19-54 years, collected from a nationally representative sample, the Korea National Health and Nutrition Examination Survey-V during 2010-2012. The associations between irregular menstruation and occupation were explored using multiple logistic regression. Compared to non-manual workers, service/sales workers had a greater odds of irregular menstruation (adjusted odds ratio [aOR]: 1.44; 95percent confidence interval [CI]: 1.04-1.99) as did manual workers and unemployed women (aOR: 1.56; 95percent CI: 1.10-2.22, aOR: 1.46; 95percent CI: 1.14-1.89, respectively). Compared to regular workers, temporary workers and unemployed women had aORs of 1.52 (95percent CI: 1.08-2.13) and 1.33 (95percent CI: 1.05-1.69), respectively. Also, when compared to full-time workers, part-time workers and unemployed women had greater odds of irregular menstruation (aOR: 1.41; 95percent CI: 1.00-2.00 and aOR: 1.29; 95percent CI: 1.03-1.63, respectively). Furthermore, compared to daytime workers, shift workers and unemployed women had greater odds irregular menstruation (aOR: 1.39; 95percent CI: 1.03-1.88 and aOR: 1.28; 95percent CI: 1.04-1.59, respectively). Women with these occupational characteristics should be screened for early diagnosis and intervention for irregular menstruation.

  20. COEVOLUTIONARY SEMANTICS OF TECHNOLOGICAL CIVILIZATION GENESIS AND EVOLUTIONARY RISK (BETWEEN THE BIOAESTHETICS AND BIOPOLITICS

    Directory of Open Access Journals (Sweden)

    V. T. Cheshko

    2016-12-01

    Full Text Available Purpose (metatask of the present work is to attempt to give a glance at the problem of existential and anthropological risk caused by the contemporary man-made civilization from the perspective of comparison and confrontation of aesthetics, the substrate of which is emotional and metaphorical interpretation of individual subjective values and politics feeding by objectively rational interests of social groups. In both cases there is some semantic gap present between the represented social reality and its representation in perception of works of art and in the political doctrines as well. Methodology of the research is evolutionary anthropologicalcomparativistics. Originality of the conducted analysis comes to the following: As the antithesis to biological and social reductionism in interpretation of the phenomenon of bio-power it is proposed a co-evolutionary semantic model in accordance with which the described semantic gap is of the substantial nature related to the complex module organization of a consistent and adaptive human strategy consisting of three associated but independently functional modules (genetic, cultural and techno-rational. Evolutionary trajectory of all anthropogenesis components including civilization cultural and social-political evolution is identified by the proportion between two macro variables – evolutionary effectiveness and evolutionary stability (sameness, i.e. preservation in the context of consequential transformations of some invariants of Homo sapiens species specificity organization. It should be noted that inasmuch as in respect to human, some modules of the evolutionary (adaptive strategy assume self-reflection attributes, it would be more correctly to state about evolutionary correctness, i.e. correspondence to some perfection. As a result, the future of human nature depends not only on the rationalist principles of ethics of Homo species (the archaism of Jurgen Habermas, but also on the holistic and

  1. Advances in electron dosimetry of irregular fields

    International Nuclear Information System (INIS)

    Mendez V, J.

    1998-01-01

    In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm 2 with percentile error less than 1 % . (Author)

  2. New Model for Ionospheric Irregularities at Mars

    Science.gov (United States)

    Keskinen, M. J.

    2018-03-01

    A new model for ionospheric irregularities at Mars is presented. It is shown that wind-driven currents in the dynamo region of the Martian ionosphere can be unstable to the electromagnetic gradient drift instability. This plasma instability can generate ionospheric density and magnetic field irregularities with scale sizes of approximately 15-20 km down to a few kilometers. We show that the instability-driven magnetic field fluctuation amplitudes relative to background are correlated with the ionospheric density fluctuation amplitudes relative to background. Our results can explain recent observations made by the Mars Atmosphere and Volatile EvolutioN spacecraft in the Martian ionosphere dynamo region.

  3. High energy model for irregular absorbing particles

    International Nuclear Information System (INIS)

    Chiappetta, Pierre.

    1979-05-01

    In the framework of a high energy formulation of relativistic quantum scattering a model is presented which describes the scattering functions and polarization of irregular absorbing particles, whose dimensions are greater than the incident wavelength. More precisely in the forward direction an amplitude parametrization of eikonal type is defined which generalizes the usual diffraction theory, and in the backward direction a reflective model is used including a shadow function. The model predictions are in good agreement with the scattering measurements off irregular compact and fluffy particles performed by Zerull, Giese and Weiss (1977)

  4. Synchronizing data from irregularly sampled sensors

    Science.gov (United States)

    Uluyol, Onder

    2017-07-11

    A system and method include receiving a set of sampled measurements for each of multiple sensors, wherein the sampled measurements are at irregular intervals or different rates, re-sampling the sampled measurements of each of the multiple sensors at a higher rate than one of the sensor's set of sampled measurements, and synchronizing the sampled measurements of each of the multiple sensors.

  5. Natural convection inside an irregular porous cavity

    International Nuclear Information System (INIS)

    Beltran, Jorge I. LLagostera; Trevisan, Osvair Vidal

    1990-01-01

    Natural convection flow induced by heating from below in a irregular porous cavity is investigated numerically. The influence of the modified Rayleigh number and geometric ratios on heat transfer and fluid flow is studied. Global and local Nusselt for Rayleigh numbers covering the range 0 - 1600 and for several geometric ratios. The fluid flow and the temperature field are illustrated by contour maps. (author)

  6. Fitting Irregular Shape Figures into Irregular Shape Areas for the Nesting Problem in the Leather Industry

    Directory of Open Access Journals (Sweden)

    Guevara-Palma Luis

    2015-01-01

    Full Text Available The nesting problem of irregular shapes within irregular areas has been studied from several approaches due to their application in different industries. The particular case of cutting leather involves several restrictions that add complexity to this problem, it is necessary to generate products that comply with the quality required by customers This paper presents a methodology for the accommodation of irregular shapes in an irregular area (leather considering the constraints set by the footwear industry, and the results of this methodology when applied by a computer system. The scope of the system is to develop a working prototype that operates under the guidelines of a commercial production line of a sponsor company. Preliminary results got a reduction of 70% of processing time and improvement of 5% to 7% of the area usage when compared with manual accommodation.

  7. Radar Observations of 8.3-m scale equatorial spread F irregularities over Trivandrum

    Directory of Open Access Journals (Sweden)

    D. Tiwari

    2004-03-01

    Full Text Available In this paper, we present observations of equatorial spread F (ESF irregularities made using a newly installed 18MHz radar located at Trivandrum. We characterize the morphology and the spectral parameters of the 8.3-m ESF irregularities which are found to be remarkably different from that observed so extensively at the 3-m scale size. We also present statistical results of the irregularities in the form of percentage occurrence of the echoes and spectral parameters (SNR, Doppler velocity, Spectral width. The Doppler spectra are narrower, less structured and less variable in time as compared to those observed for 3-m scale size. We have never observed the ESF irregularity velocities to be supersonic here unlike those at Jicamarca, and the velocities are found to be within ±200ms–1. The spectral widths are found to be less than 150ms–1. Hence, the velocities and spectral width both are smaller than those reported for 3-m scale size. The velocities and spectral widths are further found to be much smaller than those of the American sector. These observations are compared with those reported elsewhere and discussed in the light of present understanding on the ESF irregularities at different wavelengths.

    Key words. Ionoshphere (equatorial ionosphere, plasma waves and instabilities; ionospheric irregularities

  8. Radar Observations of 8.3-m scale equatorial spread F irregularities over Trivandrum

    Directory of Open Access Journals (Sweden)

    D. Tiwari

    2004-03-01

    Full Text Available In this paper, we present observations of equatorial spread F (ESF irregularities made using a newly installed 18MHz radar located at Trivandrum. We characterize the morphology and the spectral parameters of the 8.3-m ESF irregularities which are found to be remarkably different from that observed so extensively at the 3-m scale size. We also present statistical results of the irregularities in the form of percentage occurrence of the echoes and spectral parameters (SNR, Doppler velocity, Spectral width. The Doppler spectra are narrower, less structured and less variable in time as compared to those observed for 3-m scale size. We have never observed the ESF irregularity velocities to be supersonic here unlike those at Jicamarca, and the velocities are found to be within ±200ms–1. The spectral widths are found to be less than 150ms–1. Hence, the velocities and spectral width both are smaller than those reported for 3-m scale size. The velocities and spectral widths are further found to be much smaller than those of the American sector. These observations are compared with those reported elsewhere and discussed in the light of present understanding on the ESF irregularities at different wavelengths. Key words. Ionoshphere (equatorial ionosphere, plasma waves and instabilities; ionospheric irregularities

  9. Generating Performance Models for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Ryan D.; Tallent, Nathan R.; Vishnu, Abhinav; Kerbyson, Darren J.; Hoisie, Adolfy

    2017-05-30

    Many applications have irregular behavior --- non-uniform input data, input-dependent solvers, irregular memory accesses, unbiased branches --- that cannot be captured using today's automated performance modeling techniques. We describe new hierarchical critical path analyses for the \\Palm model generation tool. To create a model's structure, we capture tasks along representative MPI critical paths. We create a histogram of critical tasks with parameterized task arguments and instance counts. To model each task, we identify hot instruction-level sub-paths and model each sub-path based on data flow, instruction scheduling, and data locality. We describe application models that generate accurate predictions for strong scaling when varying CPU speed, cache speed, memory speed, and architecture. We present results for the Sweep3D neutron transport benchmark; Page Rank on multiple graphs; Support Vector Machine with pruning; and PFLOTRAN's reactive flow/transport solver with domain-induced load imbalance.

  10. Long wavelength irregularities in the equatorial electrojet

    OpenAIRE

    Kudeki, E.; Farley, D. T.; Fejer, Bela G.

    1982-01-01

    We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach...

  11. Improving Transactional Memory Performance for Irregular Applications

    OpenAIRE

    Pedrero, Manuel; Gutiérrez, Eladio; Romero, Sergio; Plata, Óscar

    2015-01-01

    Transactional memory (TM) offers optimistic concurrency support in modern multicore archi- tectures, helping the programmers to extract parallelism in irregular applications when data dependence information is not available before runtime. In fact, recent research focus on ex- ploiting thread-level parallelism using TM approaches. However, the proposed techniques are of general use, valid for any type of application. This work presents ReduxSTM, a software TM system specially d...

  12. Star formation histories of irregular galaxies

    International Nuclear Information System (INIS)

    Gallagher, J.S. III; Hunter, D.A.; Tutukov, A.V.

    1984-01-01

    We explore the star formation histories of a selection of irregular and spiral galaxies by using three parameters that sample the star formation rate (SFR) at different epochs: (1) the mass of a galaxy in the form of stars measures the SFR integrated over a galaxy's lifetime; (2) the blue luminosity is dominated primarily by stars formed over the past few billion years; and (3) Lyman continuum photon fluxes derived from Hα luminosities give the current ( 8 yr) SFR

  13. Parallel Computing Strategies for Irregular Algorithms

    Science.gov (United States)

    Biswas, Rupak; Oliker, Leonid; Shan, Hongzhang; Biegel, Bryan (Technical Monitor)

    2002-01-01

    Parallel computing promises several orders of magnitude increase in our ability to solve realistic computationally-intensive problems, but relies on their efficient mapping and execution on large-scale multiprocessor architectures. Unfortunately, many important applications are irregular and dynamic in nature, making their effective parallel implementation a daunting task. Moreover, with the proliferation of parallel architectures and programming paradigms, the typical scientist is faced with a plethora of questions that must be answered in order to obtain an acceptable parallel implementation of the solution algorithm. In this paper, we consider three representative irregular applications: unstructured remeshing, sparse matrix computations, and N-body problems, and parallelize them using various popular programming paradigms on a wide spectrum of computer platforms ranging from state-of-the-art supercomputers to PC clusters. We present the underlying problems, the solution algorithms, and the parallel implementation strategies. Smart load-balancing, partitioning, and ordering techniques are used to enhance parallel performance. Overall results demonstrate the complexity of efficiently parallelizing irregular algorithms.

  14. The Impact of Irregular Warfare on the US Army

    National Research Council Canada - National Science Library

    McDonald, III, Roger L

    2006-01-01

    Although the U.S. Army has yet to clearly define irregular warfare, it is imperative that the Army take near-term action to enhance the ability of Soldiers and units to operate effectively in an irregular warfare environment...

  15. State reconstruction and irregular wavefunctions for the hydrogen atom

    Science.gov (United States)

    Krähmer, D. S.; Leonhardt, U.

    1997-07-01

    Inspired by a recently proposed procedure by Leonhardt and Raymer for wavepacket reconstruction, we calculate the irregular wavefunctions for the bound states of the Coulomb potential. We select the irregular solutions which have the simplest semiclassical limit.

  16. On irregularity strength of disjoint union of friendship graphs

    Directory of Open Access Journals (Sweden)

    Ali Ahmad

    2013-11-01

    Full Text Available We investigate the vertex total and edge total modication of the well-known irregularity strength of graphs. We have determined the exact values of the total vertex irregularity strength and the total edge irregularity strength of a disjoint union of friendship graphs.

  17. 16 CFR 501.6 - Cellulose sponges, irregular dimensions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

  18. Kilometer-Spaced GNSS Array for Ionospheric Irregularity Monitoring

    Science.gov (United States)

    Su, Yang

    This dissertation presents automated, systematic data collection, processing, and analysis methods for studying the spatial-temporal properties of Global Navigation Satellite Systems (GNSS) scintillations produced by ionospheric irregularities at high latitudes using a closely spaced multi-receiver array deployed in the northern auroral zone. The main contributions include 1) automated scintillation monitoring, 2) estimation of drift and anisotropy of the irregularities, 3) error analysis of the drift estimates, and 4) multi-instrument study of the ionosphere. A radio wave propagating through the ionosphere, consisting of ionized plasma, may suffer from rapid signal amplitude and/or phase fluctuations known as scintillation. Caused by non-uniform structures in the ionosphere, intense scintillation can lead to GNSS navigation and high-frequency (HF) communication failures. With specialized GNSS receivers, scintillation can be studied to better understand the structure and dynamics of the ionospheric irregularities, which can be parameterized by altitude, drift motion, anisotropy of the shape, horizontal spatial extent and their time evolution. To study the structuring and motion of ionospheric irregularities at the sub-kilometer scale sizes that produce L-band scintillations, a closely-spaced GNSS array has been established in the auroral zone at Poker Flat Research Range, Alaska to investigate high latitude scintillation and irregularities. Routinely collecting low-rate scintillation statistics, the array database also provides 100 Hz power and phase data for each channel at L1/L2C frequency. In this work, a survey of seasonal and hourly dependence of L1 scintillation events over the course of a year is discussed. To efficiently and systematically study scintillation events, an automated low-rate scintillation detection routine is established and performed for each day by screening the phase scintillation index. The spaced-receiver technique is applied to cross

  19. Locating irregularly shaped clusters of infection intensity

    DEFF Research Database (Denmark)

    Yiannakoulias, Niko; Wilson, Shona; Kariuki, H. Curtis

    2010-01-01

    of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the "greedy growth scan" is a suitable method for exploratory geographical analysis...... for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis...

  20. Equatorial Ionospheric Irregularities Study from ROCSAT Data

    Science.gov (United States)

    2017-10-20

    UNLIMITED: PB Public Release 13. SUPPLEMENTARY NOTES 14. ABSTRACT Ionospheric irregularity/scintillation occurrences can be caused by external driving ...Academia Sinica, Taipei, Taiwan e-mail: chliu2@gate.sinica.edu.tw phone :886-3-4227151x34757 CoPI: Shin-Yi Su Institution: National Central...University, Chung-Li, Taiwan e-mail: sysu@csrsr.ncu.edu.tw phone :886-3-4227151x57643 CoPI: Lung-Chi Tsai Institution: National Central University, Chung-Li

  1. Artificial periodic irregularities in the auroral ionosphere

    Directory of Open Access Journals (Sweden)

    M. T. Rietveld

    1996-12-01

    Full Text Available Artificial periodic irregularities (API are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at mid-latitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75–115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50–70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the

  2. Legal aspects of the EU policy on irregular immigration

    Directory of Open Access Journals (Sweden)

    Voinikov Vadim

    2015-12-01

    Full Text Available This article addresses the issues pertaining to the adoption and development of legislation on irregular migration in the context of uncontrolled growth in the number of immigrants from North Africa and the Middle East to the EU. The article attempts at studying the EU legislation on irregular migration, classifying it, and analysing the prospects of EU migration legislation in the light of an increase in irregular immigration into the EU. The author systematises, classifies the current EU legislation on irregular immigration, and analyses the conditions, in which this legislation was developed. Using the legislation analysis method, the author proposes the following system of EU legislation on irregular immigration: rules preventing assistance to irregular immigration, rules preventing employment of irregular immigrants, rules on the return of irregular migrants and readmission, rules on border control, and rules on collaboration with third countries. The author pays special attention to analysing the current state of irregular immigration to the EU, which was dubbed the ‘greatest migration crisis in Europe’. The conclusion is that the European Union succeeded in the development of pioneering legislation on irregular immigration, which can serve as the basis for reception by other states. However, changes in the political and economic situation in the EU’s southern borderlands made the current legal mechanisms incapable of withstanding new threats. It necessitates a radical reform of the legislation on irregular immigration.

  3. The transition from regular to irregular motions, explained as travel on Riemann surfaces

    International Nuclear Information System (INIS)

    Calogero, F; Santini, P M; Gomez-Ullate, D; Sommacal, M

    2005-01-01

    We introduce and discuss a simple Hamiltonian dynamical system, interpretable as a three-body problem in the (complex) plane and providing the prototype of a mechanism explaining the transition from regular to irregular motions as travel on Riemann surfaces. The interest of this phenomenology-illustrating the onset in a deterministic context of irregular motions-is underlined by its generality, suggesting its eventual relevance to understand natural phenomena and experimental investigations. Here only some of our main findings are reported, without detailing their proofs: a more complete presentation will be published elsewhere

  4. Irregularities of ionospheric VTEC during lightning activity over Antarctic Peninsula

    International Nuclear Information System (INIS)

    Suparta, W; Wan Mohd Nor, W N A

    2017-01-01

    This paper investigates the irregularities of vertical total electron content (VTEC) during lightning activity and geomagnetic quiet days over Antarctic Peninsula in year 2014. During the lightning event, the ionosphere may be disturbed which may cause disruption in the radio signal. Thus, it is important to understand the influence of lightning on VTEC in the study of upper-lower interaction. The lightning data is obtained from World Wide Lightning Location Network (WWLLN) and the VTEC data has analyzed from Global Positioning System (GPS) for O’Higgins (OHI3), Palmer (PALV), and Rothera (ROTH). The results demonstrate the VTEC variation of ∼0.2 TECU during low lightning activity which could be caused by energy dissipation through lightning discharges from troposphere into the thermosphere. (paper)

  5. Sustainability and collapse in a coevolutionary model of local resource stocks and behavioral patterns on a social network

    Science.gov (United States)

    Wiedermann, Marc; Donges, Jonathan F.; Heitzig, Jobst; Kurths, Jürgen

    2014-05-01

    When investigating the causes and consequences of global change, the collective behavior of human beings is considered as having a considerable impact on natural systems. In our work, we propose a conceptual coevolutionary model simulating the dynamics of local renewable resources in interaction with simplistic societal agents exploiting those resources. The society is represented by a social network on which social traits may be transmitted between agents. These traits themselves induce a certain rate of exploitation of the resource, leading either to its depletion or sustainable existence. Traits are exchanged probabilistically according to their instantaneous individual payoff, and hence this process depends on the status of the natural resource. At the same time agents may adaptively restructure their set of acquaintances. Connections with agents having a different trait may be broken while new connections with agents of the same trait are established. We investigate which choices of social parameters, like the frequency of social interaction, rationality and rate of social network adaptation, cause the system to end in a sustainable state and, hence, what can be done to avoid a collapse of the entire system. The importance and influence of the social network structure is analyzed by the variation of link-densities in the underlying network topology and shows significant influence on the expected outcome of the model. For a static network with no adaptation we find a robust phase transition between the two different regimes, sustainable and non-sustainable, which co-exist in parameter space. High connectivity within the social network, e.g., high link-densities, in combination with a fast rate of social learning lead to a likely collapse of the entire co-evolutionary system, whereas slow learning and small network connectivity very likely result in the sustainable existence of the natural resources. Collapse may be avoided by an intelligent rewiring, e

  6. Computing proton dose to irregularly moving targets

    International Nuclear Information System (INIS)

    Phillips, Justin; Gueorguiev, Gueorgui; Grassberger, Clemens; Dowdell, Stephen; Paganetti, Harald; Sharp, Gregory C; Shackleford, James A

    2014-01-01

    Purpose: While four-dimensional computed tomography (4DCT) and deformable registration can be used to assess the dose delivered to regularly moving targets, there are few methods available for irregularly moving targets. 4DCT captures an idealized waveform, but human respiration during treatment is characterized by gradual baseline shifts and other deviations from a periodic signal. This paper describes a method for computing the dose delivered to irregularly moving targets based on 1D or 3D waveforms captured at the time of delivery. Methods: The procedure uses CT or 4DCT images for dose calculation, and 1D or 3D respiratory waveforms of the target position at time of delivery. Dose volumes are converted from their Cartesian geometry into a beam-specific radiological depth space, parameterized in 2D by the beam aperture, and longitudinally by the radiological depth. In this new frame of reference, the proton doses are translated according to the motion found in the 1D or 3D trajectory. These translated dose volumes are weighted and summed, then transformed back into Cartesian space, yielding an estimate of the dose that includes the effect of the measured breathing motion. The method was validated using a synthetic lung phantom and a single representative patient CT. Simulated 4DCT was generated for the phantom with 2 cm peak-to-peak motion. Results: A passively-scattered proton treatment plan was generated using 6 mm and 5 mm smearing for the phantom and patient plans, respectively. The method was tested without motion, and with two simulated breathing signals: a 2 cm amplitude sinusoid, and a 2 cm amplitude sinusoid with 3 cm linear drift in the phantom. The tumor positions were equally weighted for the patient calculation. Motion-corrected dose was computed based on the mid-ventilation CT image in the phantom and the peak exhale position in the patient. Gamma evaluation was 97.8% without motion, 95.7% for 2 cm sinusoidal motion, 95.7% with 3 cm drift in

  7. Actors and factors in the governance of irregular migration : a comparative analysis of Albanian, Georgian, Ukrainian, Pakistani and Afghani irregular flows to Greece

    OpenAIRE

    TRIANDAFYLLIDOU, Anna

    2015-01-01

    Proceedings from the conference "Governing Irregular Migration : States, Actors and Intermediaries", Athens 8-9 July 2015 The loss of over a thousand human lives in the effort to cross the Mediterranean during April 2015 has once again drawn media and political attention to the challenges that the EU is facing in its efforts to govern migration and asylum. However, what seems to be still far from complete is our (the experts and the politicians) understanding of what drives people to put t...

  8. Long wavelength irregularities in the equatorial electrojet

    International Nuclear Information System (INIS)

    Kudeki, E.; Farley, D.T.; Fejer, B.G.

    1982-01-01

    We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach or exceed the ion-acoustic velocity even though the horizontal phase velocity of the wave is considerably smaller. A straightforward extension to the long wavelength regime of the usual linear theory of the electrojet instability explains this and several other observed features of these dominant primary waves

  9. Irregular employment amongst migrants in Spanish cities.

    Science.gov (United States)

    Sole, C; Ribas, N; Bergalli, V; Parella, S

    1998-04-01

    This article presents the irregular employment situation of non-European union immigrants in Spanish cities. Foreign labor is remarkable for its heterogeneity in terms of country of origin, demographic characteristics, and the different ways in which immigrants have entered the job market. Legal immigrants tend to concentrate in five different branches of activity, such as domestic service (mostly women), hotel and restaurant industry, agriculture, building and retail trade. Migrants who work in agriculture suffer the worst labor conditions than all other migrants. However, all migrants experience difficulty in obtaining residency and labor permits. Four integration strategies among Moroccan immigrants in Catalonia are discussed and can be viewed as support networks of the immigrants.

  10. Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant-folivore coevolutionary processes?

    Energy Technology Data Exchange (ETDEWEB)

    Rivas-Ubach, Albert [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland Washington 99354 USA; CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; Hódar, José A. [Grupo de Ecología Terrestre, Departamento de Biología Animal y Ecología, Facultad de Ciencias, Universidad de Granada, 18071 Granada Spain; Sardans, Jordi [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain; Kyle, Jennifer E. [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Kim, Young-Mo [Biological Sciences Division, Pacific Northwest National Laboratory, Richland Washington 99354 USA; Oravec, Michal [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Urban, Otmar [Global Change Research Centre, Academy of Sciences of the Czech Republic, Bĕlidla 4a CZ-603 00 Brno Czech Republic; Guenther, Alex [Department of Earth System Science, University of California, Irvine California 92697 USA; Peñuelas, Josep [CREAF, Cerdanyola del Vallès 08913 Catalonia Spain; CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Vallès 08913 Catalonia Spain

    2016-06-02

    The debate whether the coevolution of plants and insects or macroevolutionary processes (phylogeny) is the main driver determining the arsenal of molecular defensive compounds of plants remains unresolved. Attacks by herbivorous insects affect not only the composition of defensive compounds in plants but the entire metabolome (the set of molecular metabolites), including defensive compounds. Metabolomes are the final products of genotypes and are directly affected by macroevolutionary processes, so closely related species should have similar metabolomic compositions and may respond in similar ways to attacks by folivores. We analyzed the elemental compositions and metabolomes of needles from Pinus pinaster, P. nigra and P. sylvestris to determine if these closely related Pinus species with different coevolutionary histories with the caterpillars of the processionary moth respond similarly to attacks by this lepidopteran. All pines had different metabolomes and metabolic responses to herbivorous attack. The metabolomic variation among the pine species and the responses to folivory reflected their macroevolutionary relationships, with P. pinaster having the most divergent metabolome. The concentrations of phenolic metabolites were generally not higher in the attacked trees, which had lower concentrations of terpenes, suggesting that herbivores avoid individuals with high concentrations of terpenes. Our results suggest that macroevolutionary history plays important roles in the metabolomic responses of these pine species to folivory, but plant-insect coevolution probably constrains those responses. Combinations of different evolutionary factors and trade-offs are likely responsible for the different responses of each species to folivory, which is not necessarily exclusively linked to plant-insect coevolution.

  11. Irregular activity arises as a natural consequence of synaptic inhibition

    International Nuclear Information System (INIS)

    Terman, D.; Rubin, J. E.; Diekman, C. O.

    2013-01-01

    Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects

  12. Irregular activity arises as a natural consequence of synaptic inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Terman, D., E-mail: terman@math.ohio-state.edu [Department of Mathematics, The Ohio State University, Columbus, Ohio 43210 (United States); Rubin, J. E., E-mail: jonrubin@pitt.edu [Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Diekman, C. O., E-mail: diekman@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)

    2013-12-15

    Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects.

  13. Decomposing Oriented Graphs into Six Locally Irregular Oriented Graphs

    DEFF Research Database (Denmark)

    Bensmail, Julien; Renault, Gabriel

    2016-01-01

    An undirected graph G is locally irregular if every two of its adjacent vertices have distinct degrees. We say that G is decomposable into k locally irregular graphs if there exists a partition E1∪E2∪⋯∪Ek of the edge set E(G) such that each Ei induces a locally irregular graph. It was recently co...

  14. Characteristics of ionospheric irregularities causing scintillations at VHF/UHF

    International Nuclear Information System (INIS)

    Vats, H.O.; Deshpande, M.R.; Rastogi, R.G.

    1978-01-01

    Some properties of ionization irregularities using amplitude scintillation records of radio beacons from ATS-6 (phase II) at Ootacamund, India have been investigated. For the estimation of scale-size and strength of the irregularities a simple diffraction model has been used which explains only weak and moderate equatorial scintillation observations. It was found that the scale sizes of day time E-region irregularities are smaller than those in the F-region during night time in addition, irregularities are generated initially at large scale sizes which later break up into smaller scale sizes

  15. Experimental Study of Irregular Waves on a Gravel Beach

    Science.gov (United States)

    Hu, Nai-Ren; Wu, Yun-Ta; Hwung, Hwung-Hweng; Yang, Ray-Yeng

    2017-04-01

    In the east coast of Taiwan, the sort grain size more belongs to cobble or gravel, which is physically distinct compared to the sandy beach in the west coast of Taiwan. Although gravel beaches can dissipate more of wave energy, gravel beaches were eroded and coastal road were damaged especially during typhoons. The purpose of this study is to investigate the geomorphological response of gravel beach due to irregular waves. This experiment was carry out in a 21m long, 50 cm wide, 70 cm high wave tank at Tainan Hydraulics Laboratory, National Cheng-Kung University, Taiwan. To simulate of the geometry in the east coast of Taiwan, a physical model with 1/36 scale-down was used, in which the seawall was 10cm built upon a 1:10 slope and gravel grains with D50 being 3.87 mm was nourished in front of the seawall. In terms of typhoon-scale wave condition, irregular waves with scale-down conditions were generated for 600 s for each scenarios and, three different water levels with respect to the gravel beach are designed. Application of laser combined with image processing to produce 3D topographic map, the erosion zone and accretion zone would be found. The resulting morphological change of gravel beach will be measured using an integrated laser and image processing tool to have 3D topographic maps. It is expected to have more understanding about under what conditions the gravel coasts suffer the least damage. In particular, the relation between erosion rates of gravel beach, the angle of gravel slope and the length of the plane on the gravel slope will be achieved

  16. ESA' s novel gravitational modeling of irregular planetary bodies

    Science.gov (United States)

    Ortega, Guillermo

    A detailed understanding and modeling of the gravitational modeling is required for realistic investigation of the dynamics of orbits close to irregularly shaped bodies. Gravity field modelling up to a certain maximum spherical harmonic degree N involves N2 unkown spherical harmonic coefficients or complex harmonics. The corresponding number of matrix entries reaches till N4 . For missions like CHAMP, GRACE or GOCE, the maximum degree of resolution is 75, 150 and 300 respectively. Therefore, the number of unknowns for a satellite like GOCE will be around 100.000. Since these missions usually fly for a period of time of several years, the number of observations is huge. Hence, gravity field recovery from these missions is a high demanding task. The classical approaches like spherical expansion of the potential lead generally to a high number of coefficients, which reduce the software computational efficiency of the orbit propagation and which have mostly a limited physical meaning. One of the main targets of the activity is the modelling of asteroids, small moons, and cometary bodies. All celestial bodies are irregular by definition. However, the scope of the activity is broad enough as to be able to use the models and the software in quasy-regular bodies as well. Therefore the models and tools could be used for bodies such as the Moon, Mars, Venus, Deimos, Europa, Eros, Mathilda, and Churyumov-Gerasimenko, etc., being these applications relevant for scientific (Rosetta, Bepi Colombo), exploration (Exo-Mars), NEO mitigation (Don Quijote) and Earth observation (GOCE) missions of ESA.

  17. Advances in electron dosimetry of irregular fields; Avances en dosimetria de electrones de campos irregulares

    Energy Technology Data Exchange (ETDEWEB)

    Mendez V, J. [Departamento de Radioterapia, Instituto de Enfermedades Neoplasicas, Avenida Angamos Este 2520, Lima 34 (Peru)

    1998-12-31

    In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm{sup 2} with percentile error less than 1 % . (Author)

  18. Irregular radiation response of a chondrosarcoma

    International Nuclear Information System (INIS)

    Marsden, J.J.; Kember, N.F.; Shaw, J.E.H.

    1980-01-01

    The DC II mouse chondrosarcoma was shown to be a potentially valuable radiobiological tumour system since it recovered from radiation injury by regrowth from clones that could be counted in histological sections. Unfortunately, the normal growth of this tumour following s.c. implantation in the thigh was irregular both in the time before growth became evident and in the rate of growth. The response to radiation was also unreliable since tumours irradiated with the same dose (e.g. 30 Gy) showed a range of responses from shrinkage to no detectable change in growth rate. The delay in normal growth can be attributed largely to delays in vascularization while changes in growth rate may be explained by differences in tumour architecture. Radiation response may depend on variations in hypoxic fraction and in relative cellularity. Tumours having the same external dimensions may differ by a factor of 80 in the numbers of tumour cells they contain. This chondrosarcoma may prove a closer model to some human tumours than many transplantable tumours that display regular growth patterns. (author)

  19. Regularities and irregularities in order flow data

    Science.gov (United States)

    Theissen, Martin; Krause, Sebastian M.; Guhr, Thomas

    2017-11-01

    We identify and analyze statistical regularities and irregularities in the recent order flow of different NASDAQ stocks, focusing on the positions where orders are placed in the order book. This includes limit orders being placed outside of the spread, inside the spread and (effective) market orders. Based on the pairwise comparison of the order flow of different stocks, we perform a clustering of stocks into groups with similar behavior. This is useful to assess systemic aspects of stock price dynamics. We find that limit order placement inside the spread is strongly determined by the dynamics of the spread size. Most orders, however, arrive outside of the spread. While for some stocks order placement on or next to the quotes is dominating, deeper price levels are more important for other stocks. As market orders are usually adjusted to the quote volume, the impact of market orders depends on the order book structure, which we find to be quite diverse among the analyzed stocks as a result of the way limit order placement takes place.

  20. Evaporation From Soil Containers With Irregular Shapes

    Science.gov (United States)

    Assouline, Shmuel; Narkis, Kfir

    2017-11-01

    Evaporation from bare soils under laboratory conditions is generally studied using containers of regular shapes where the vertical edges are parallel to the flow lines in the drying domain. The main objective of this study was to investigate the impact of irregular container shapes, for which the flow lines either converge or diverge toward the surface. Evaporation from initially saturated sand and sandy loam soils packed in cones and inverted cones was compared to evaporation from corresponding cylindrical columns. The initial evaporation rate was higher in the cones, and close to potential evaporation. At the end of the experiment, the cumulative evaporation depth in the sand cone was equal to that in the column but higher than in the inverted cone, while in the sandy loam, the order was cone > column > inverted cone. By comparison to the column, stage 1 evaporation was longer in the cones, and practically similar in the inverted cones. Stage 2 evaporation rate decreased with the increase of the evaporating surface area. These results were more pronounced in the sandy loam. For the sand column, the transition between stage 1 and stage 2 evaporation occurred when the depth of the saturation front was approximately equal to the characteristic length of the soil. However, for the cone and the inverted cone, it occurred for a shallower depth of the saturation front. It seems therefore that the concept of the characteristic length derived from the soil hydraulic properties is related to drying systems of regular shapes.

  1. Design strategies for irregularly adapting parallel applications

    International Nuclear Information System (INIS)

    Oliker, Leonid; Biswas, Rupak; Shan, Hongzhang; Sing, Jaswinder Pal

    2000-01-01

    Achieving scalable performance for dynamic irregular applications is eminently challenging. Traditional message-passing approaches have been making steady progress towards this goal; however, they suffer from complex implementation requirements. The use of a global address space greatly simplifies the programming task, but can degrade the performance of dynamically adapting computations. In this work, we examine two major classes of adaptive applications, under five competing programming methodologies and four leading parallel architectures. Results indicate that it is possible to achieve message-passing performance using shared-memory programming techniques by carefully following the same high level strategies. Adaptive applications have computational work loads and communication patterns which change unpredictably at runtime, requiring dynamic load balancing to achieve scalable performance on parallel machines. Efficient parallel implementations of such adaptive applications are therefore a challenging task. This work examines the implementation of two typical adaptive applications, Dynamic Remeshing and N-Body, across various programming paradigms and architectural platforms. We compare several critical factors of the parallel code development, including performance, programmability, scalability, algorithmic development, and portability

  2. Multiresolution Analysis Adapted to Irregularly Spaced Data

    Directory of Open Access Journals (Sweden)

    Anissa Mokraoui

    2009-01-01

    Full Text Available This paper investigates the mathematical background of multiresolution analysis in the specific context where the signal is represented by irregularly sampled data at known locations. The study is related to the construction of nested piecewise polynomial multiresolution spaces represented by their corresponding orthonormal bases. Using simple spline basis orthonormalization procedures involves the construction of a large family of orthonormal spline scaling bases defined on consecutive bounded intervals. However, if no more additional conditions than those coming from multiresolution are imposed on each bounded interval, the orthonormal basis is represented by a set of discontinuous scaling functions. The spline wavelet basis also has the same problem. Moreover, the dimension of the corresponding wavelet basis increases with the spline degree. An appropriate orthonormalization procedure of the basic spline space basis, whatever the degree of the spline, allows us to (i provide continuous scaling and wavelet functions, (ii reduce the number of wavelets to only one, and (iii reduce the complexity of the filter bank. Examples of the multiresolution implementations illustrate that the main important features of the traditional multiresolution are also satisfied.

  3. Resolution optimization with irregularly sampled Fourier data

    International Nuclear Information System (INIS)

    Ferrara, Matthew; Parker, Jason T; Cheney, Margaret

    2013-01-01

    Image acquisition systems such as synthetic aperture radar (SAR) and magnetic resonance imaging often measure irregularly spaced Fourier samples of the desired image. In this paper we show the relationship between sample locations, their associated backprojection weights, and image resolution as characterized by the resulting point spread function (PSF). Two new methods for computing data weights, based on different optimization criteria, are proposed. The first method, which solves a maximal-eigenvector problem, optimizes a PSF-derived resolution metric which is shown to be equivalent to the volume of the Cramer–Rao (positional) error ellipsoid in the uniform-weight case. The second approach utilizes as its performance metric the Frobenius error between the PSF operator and the ideal delta function, and is an extension of a previously reported algorithm. Our proposed extension appropriately regularizes the weight estimates in the presence of noisy data and eliminates the superfluous issue of image discretization in the choice of data weights. The Frobenius-error approach results in a Tikhonov-regularized inverse problem whose Tikhonov weights are dependent on the locations of the Fourier data as well as the noise variance. The two new methods are compared against several state-of-the-art weighting strategies for synthetic multistatic point-scatterer data, as well as an ‘interrupted SAR’ dataset representative of in-band interference commonly encountered in very high frequency radar applications. (paper)

  4. Irregular Homogeneity Domains in Ternary Intermetallic Systems

    Directory of Open Access Journals (Sweden)

    Jean-Marc Joubert

    2015-12-01

    Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

  5. 14 CFR 135.65 - Reporting mechanical irregularities.

    Science.gov (United States)

    2010-01-01

    ... irregularities and their correction. (b) The pilot in command shall enter or have entered in the aircraft maintenance log each mechanical irregularity that comes to the pilot's attention during flight time. Before each flight, the pilot in command shall, if the pilot does not already know, determine the status of...

  6. Uniform irradiation of irregularly shaped cavities for photodynamic therapy

    NARCIS (Netherlands)

    Rem, A. I.; van Gemert, M. J.; van der Meulen, F. W.; Gijsbers, G. H.; Beek, J. F.

    1997-01-01

    It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a

  7. Software support for irregular and loosely synchronous problems

    Science.gov (United States)

    Choudhary, A.; Fox, G.; Hiranandani, S.; Kennedy, K.; Koelbel, C.; Ranka, S.; Saltz, J.

    1992-01-01

    A large class of scientific and engineering applications may be classified as irregular and loosely synchronous from the perspective of parallel processing. We present a partial classification of such problems. This classification has motivated us to enhance FORTRAN D to provide language support for irregular, loosely synchronous problems. We present techniques for parallelization of such problems in the context of FORTRAN D.

  8. Regularisation of irregular verbs in child English second language ...

    African Journals Online (AJOL)

    Data was collected from the language of English medium preschool children. The study concludes that when the Blocking Principle interferes, children resort to a novel interlanguage rule that regularises irregular verbs. This interlanguage rule applies in a similar way to all irregular verbs, thus children produce utterances ...

  9. Irregular conformal block, spectral curve and flow equations

    International Nuclear Information System (INIS)

    Choi, Sang Kwan; Rim, Chaiho; Zhang, Hong

    2016-01-01

    Irregular conformal block is motivated by the Argyres-Douglas type of N=2 super conformal gauge theory. We investigate the classical/NS limit of irregular conformal block using the spectral curve on a Riemann surface with irregular punctures, which is equivalent to the loop equation of irregular matrix model. The spectral curve is reduced to the second order (Virasoro symmetry, SU(2) for the gauge theory) and third order (W_3 symmetry, SU(3)) differential equations of a polynomial with finite degree. The conformal and W symmetry generate the flow equations in the spectral curve and determine the irregular conformal block, hence the partition function of the Argyres-Douglas theory ala AGT conjecture.

  10. Star Formation Histories of Dwarf Irregular Galaxies

    Science.gov (United States)

    Skillman, Evan

    1995-07-01

    We propose to obtain deep WFPC2 `BVI' color-magnitude diagrams {CMDs} for the dwarf irregular {dI} Local Group galaxies GR 8, Leo A, Pegasus, and Sextans A. In addition to resolved stars, we will use star clusters, and especially any globulars, to probe the history of intense star formation. These data will allow us to map the Pop I and Pop II stellar components, and thereby construct the first detailed star formation histories for non-interacting dI galaxies. Our results will bear on a variety of astrophysical problems, including the evolution of small galaxies, distances in the Local Group, age-metallicity distributions in small galaxies, ages of dIs, and the physics of star formation. The four target galaxies are typical dI systems in terms of luminosity, gas content, and H II region abundance, and represent a range in current star forming activity. They are sufficiently near to allow us to reach to stars at M_V = 0, have 0.1 of the luminosity of the SMC and 0.25 of its oxygen abundance. Unlike the SMC, these dIs are not near giant galaxies. This project will allow the extension of our knowledge of stellar populations in star forming galaxies from the spirals in the Local Group down to its smallest members. We plan to take maximum advantage of the unique data which this project will provide. Our investigator team brings extensive and varied experience in studies of dwarf galaxies, stellar populations, imaging photometry, and stellar evolution to this project.

  11. Spatial snowdrift game in heterogeneous agent systems with co-evolutionary strategies and updating rules

    International Nuclear Information System (INIS)

    Xia Hai-Jiang; Li Ping-Ping; Ke Jian-Hong; Lin Zhen-Quan

    2015-01-01

    We propose an evolutionary snowdrift game model for heterogeneous systems with two types of agents, in which the inner-directed agents adopt the memory-based updating rule while the copycat-like ones take the unconditional imitation rule; moreover, each agent can change his type to adopt another updating rule once the number he sequentially loses the game at is beyond his upper limit of tolerance. The cooperative behaviors of such heterogeneous systems are then investigated by Monte Carlo simulations. The numerical results show the equilibrium cooperation frequency and composition as functions of the cost-to-benefit ratio r are both of plateau structures with discontinuous steplike jumps, and the number of plateaux varies non-monotonically with the upper limit of tolerance ν T as well as the initial composition of agents f a0 . Besides, the quantities of the cooperation frequency and composition are dependent crucially on the system parameters including ν T , f a0 , and r. One intriguing observation is that when the upper limit of tolerance is small, the cooperation frequency will be abnormally enhanced with the increase of the cost-to-benefit ratio in the range of 0 < r < 1/4. We then probe into the relative cooperation frequencies of either type of agents, which are also of plateau structures dependent on the system parameters. Our results may be helpful to understand the cooperative behaviors of heterogenous agent systems. (paper)

  12. Computational Analysis of Residue Interaction Networks and Coevolutionary Relationships in the Hsp70 Chaperones: A Community-Hopping Model of Allosteric Regulation and Communication.

    Directory of Open Access Journals (Sweden)

    Gabrielle Stetz

    2017-01-01

    Full Text Available Allosteric interactions in the Hsp70 proteins are linked with their regulatory mechanisms and cellular functions. Despite significant progress in structural and functional characterization of the Hsp70 proteins fundamental questions concerning modularity of the allosteric interaction networks and hierarchy of signaling pathways in the Hsp70 chaperones remained largely unexplored and poorly understood. In this work, we proposed an integrated computational strategy that combined atomistic and coarse-grained simulations with coevolutionary analysis and network modeling of the residue interactions. A novel aspect of this work is the incorporation of dynamic residue correlations and coevolutionary residue dependencies in the construction of allosteric interaction networks and signaling pathways. We found that functional sites involved in allosteric regulation of Hsp70 may be characterized by structural stability, proximity to global hinge centers and local structural environment that is enriched by highly coevolving flexible residues. These specific characteristics may be necessary for regulation of allosteric structural transitions and could distinguish regulatory sites from nonfunctional conserved residues. The observed confluence of dynamics correlations and coevolutionary residue couplings with global networking features may determine modular organization of allosteric interactions and dictate localization of key mediating sites. Community analysis of the residue interaction networks revealed that concerted rearrangements of local interacting modules at the inter-domain interface may be responsible for global structural changes and a population shift in the DnaK chaperone. The inter-domain communities in the Hsp70 structures harbor the majority of regulatory residues involved in allosteric signaling, suggesting that these sites could be integral to the network organization and coordination of structural changes. Using a network-based formalism of

  13. Co-Evolutionary Mechanisms of Emotional Bursts in Online Social Dynamics and Networks

    Directory of Open Access Journals (Sweden)

    Bosiljka Tadić

    2013-11-01

    Full Text Available Collective emotional behavior of users is frequently observed on various Web portals; however, its complexity and the role of emotions in the acting mechanisms are still not thoroughly understood. In this work, using the empirical data and agent-based modeling, a parallel analysis is performed of two archetypal systems—Blogs and Internet-Relayed-Chats—both of which maintain self-organized dynamics but not the same communication rules and time scales. The emphasis is on quantifying the collective emotions by means of fractal analysis of the underlying processes as well as topology of social networks, which arise and co-evolve in these stochastic processes. The results reveal that two distinct mechanisms, which are based on different use of emotions (an emotion is characterized by two components, arousal and valence, are intrinsically associated with two classes of emergent social graphs. Their hallmarks are the evolution of communities in accordance with the excess of the negative emotions on popular Blogs, on one side, and smooth spreading of the Bot’s emotional impact over the entire hierarchical network of chats, on the other. Another emphasis of this work is on the understanding of nonextensivity of the emotion dynamics; it was found that, in its own way, each mechanism leads to a reduced phase space of the emotion components when the collective dynamics takes place. That a non-additive entropy describes emotion dynamics, is further confirmed by computing the q-generalized Kolmogorov-Sinai entropy rate in the empirical data of chats as well as in the simulations of interacting emotional agents and Bots.

  14. How Many Protein Sequences Fold to a Given Structure? A Coevolutionary Analysis.

    Science.gov (United States)

    Tian, Pengfei; Best, Robert B

    2017-10-17

    Quantifying the relationship between protein sequence and structure is key to understanding the protein universe. A fundamental measure of this relationship is the total number of amino acid sequences that can fold to a target protein structure, known as the "sequence capacity," which has been suggested as a proxy for how designable a given protein fold is. Although sequence capacity has been extensively studied using lattice models and theory, numerical estimates for real protein structures are currently lacking. In this work, we have quantitatively estimated the sequence capacity of 10 proteins with a variety of different structures using a statistical model based on residue-residue co-evolution to capture the variation of sequences from the same protein family. Remarkably, we find that even for the smallest protein folds, such as the WW domain, the number of foldable sequences is extremely large, exceeding the Avogadro constant. In agreement with earlier theoretical work, the calculated sequence capacity is positively correlated with the size of the protein, or better, the density of contacts. This allows the absolute sequence capacity of a given protein to be approximately predicted from its structure. On the other hand, the relative sequence capacity, i.e., normalized by the total number of possible sequences, is an extremely tiny number and is strongly anti-correlated with the protein length. Thus, although there may be more foldable sequences for larger proteins, it will be much harder to find them. Lastly, we have correlated the evolutionary age of proteins in the CATH database with their sequence capacity as predicted by our model. The results suggest a trade-off between the opposing requirements of high designability and the likelihood of a novel fold emerging by chance. Published by Elsevier Inc.

  15. Traffic dispersion through a series of signals with irregular split

    Science.gov (United States)

    Nagatani, Takashi

    2016-01-01

    We study the traffic behavior of a group of vehicles moving through a sequence of signals with irregular splits on a roadway. We present the stochastic model of vehicular traffic controlled by signals. The dynamic behavior of vehicular traffic is clarified by analyzing traffic pattern and travel time numerically. The group of vehicles breaks up more and more by the irregularity of signal's split. The traffic dispersion is induced by the irregular split. We show that the traffic dispersion depends highly on the cycle time and the strength of split's irregularity. Also, we study the traffic behavior through the series of signals at the green-wave strategy. The dependence of the travel time on offset time is derived for various values of cycle time. The region map of the traffic dispersion is shown in (cycle time, offset time)-space.

  16. Irregular Warfare: Impact on Future Professional Military Education

    National Research Council Canada - National Science Library

    Paschal, David G

    2006-01-01

    ... to operate effectively in an irregular warfare environment. The utility of a decisive war between nation states continues to decline and will eventually reach critical mass based upon the extreme imbalance of military power and a U.S. monopoly...

  17. Irregular Warfare: Special Operations Joint Professional Military Education Transformation

    National Research Council Canada - National Science Library

    Cannady, Bryan H

    2008-01-01

    ... on today's battlefront in Afghanistan and Iraq and in the Global War on Terrorism (GWOT). At the forefront of the GWOT and irregular warfare are the United States Special Operations Command (USSOCOM...

  18. Drug Intoxicated Irregular Fighters: Complications, Dangers, and Responses

    National Research Council Canada - National Science Library

    Kan, Paul R

    2008-01-01

    .... Drug consumption in contemporary wars has coincided with the use of child soldiers, has led to increased unpredictability among irregular fighters, provided the conditions for the breakdown of social...

  19. Justice: A Problem for Military Ethics during Irregular War

    National Research Council Canada - National Science Library

    Bauer, John W

    2008-01-01

    ... is?" or "Justice according to whom?" The relative nature of the term "justice" creates a problem for military ethics, particularly when soldiers try to determine what actions are morally acceptable when they are engaged in irregular warfare...

  20. Irregular Warfare: New Challenges for Civil-Military Relations

    National Research Council Canada - National Science Library

    Cronin, Patrick M

    2008-01-01

    .... Irregular warfare introduces new complications to what Eliot Cohen has called an unequal dialogue between civilian and military leaders in which civilian leaders hold the true power but must modulate...

  1. Role of parametric decay instabilities in generating ionospheric irregularities

    International Nuclear Information System (INIS)

    Kuo, S.P.; Cheo, B.R.; Lee, M.C.

    1983-01-01

    We show that purely growing instabilities driven by the saturation spectrum of parametric decay instabilities can produce a broad spectrum of ionospheric irregularities. The threshold field Vertical BarE/sub th/Vertical Bar of the instabilities decreases with the scale lengths lambda of the ionospheric irregularities as Vertical BarE/sub th/Vertical Barproportionallambda -2 in the small-scale range ( -2 with scale lengths larger than a few kilometers. The excitation of kilometer-scale irregularities is strictly restricted by the instabilities themselves and by the spatial inhomogeneity of the medium. These results are drawn from the analyses of four-wave interaction. Ion-neutral collisions impose no net effect on the instabilities when the excited ionospheric irregularities have a field-aligned nature

  2. Punctuated Equilibrium in Statistical Models of Generalized Coevolutionary Resilience: How Sudden Ecosystem Transitions Can Entrain Both Phenotype Expression and Darwinian Selection

    Science.gov (United States)

    Wallace, Rodrick; Wallace, Deborah

    We argue that mesoscale ecosystem resilience shifts akin to sudden phase transitions in physical systems can entrain similarly punctuated events of gene expression on more rapid time scales, and, in part through such means, slower changes induced by selection pressure, triggering punctuated equilibrium Darwinian evolutionary transitions on geologic time scales. The approach reduces ecosystem, gene expression, and Darwinian genetic dynamics to a least common denominator of information sources interacting by crosstalk at markedly differing rates. Pettini's 'topological hypothesis', via a homology between information source uncertainty and free energy density, generates a regression-like class of statistical models of sudden coevolutionary phase transition based on the Rate Distortion and Shannon-McMillan Theorems of information theory which links all three levels. A mathematical treatment of Holling's extended keystone hypothesis regarding the particular role of mesoscale phenomena in entraining both slower and faster dynamical structures produces the result. A main theme is the necessity of a cognitive paradigm for gene expression, mirroring I. Cohen's cognitive approach to immune function. Invocation of the necessary conditions imposed by the asymptotic limit theorems of communication theory enables us to penetrate one layer more deeply before needing to impose an empirically-derived phenomenological system of 'Onsager relation' recursive coevolutionary stochastic differential equations. Extending the development to second order via a large deviations argument permits modeling the influence of human cultural structures on ecosystems as 'farming'.

  3. Edge irregular total labellings for graphs of linear size

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Miškuf, J.

    2009-01-01

    As an edge variant of the well-known irregularity strength of a graph G = (V, E) we investigate edge irregular total labellings, i.e. functions f : V ∪ E → {1, 2, ..., k} such that f (u) + f (u v) + f (v) ≠ f (u) + f (u v) + f (v) for every pair of different edges u v, u v ∈ E. The smallest possi...

  4. Design Optimization of Irregular Cellular Structure for Additive Manufacturing

    Science.gov (United States)

    Song, Guo-Hua; Jing, Shi-Kai; Zhao, Fang-Lei; Wang, Ye-Dong; Xing, Hao; Zhou, Jing-Tao

    2017-09-01

    Irregularcellular structurehas great potential to be considered in light-weight design field. However, the research on optimizing irregular cellular structures has not yet been reporteddue to the difficulties in their modeling technology. Based on the variable density topology optimization theory, an efficient method for optimizing the topology of irregular cellular structures fabricated through additive manufacturing processes is proposed. The proposed method utilizes tangent circles to automatically generate the main outline of irregular cellular structure. The topological layoutof each cellstructure is optimized using the relative density informationobtained from the proposed modified SIMP method. A mapping relationship between cell structure and relative densityelement is builtto determine the diameter of each cell structure. The results show that the irregular cellular structure can be optimized with the proposed method. The results of simulation and experimental test are similar for irregular cellular structure, which indicate that the maximum deformation value obtained using the modified Solid Isotropic Microstructures with Penalization (SIMP) approach is lower 5.4×10-5 mm than that using the SIMP approach under the same under the same external load. The proposed research provides the instruction to design the other irregular cellular structure.

  5. Stability Analysis Method for Rock Slope with an Irregular Shear Plane Based on Interface Model

    Directory of Open Access Journals (Sweden)

    Changqing Qi

    2018-01-01

    Full Text Available Landslide developed in rock mass usually has irregular shear plane. An approach for calculating distributed factor of safety of the irregular shear plane was put forward in this paper. The presented method can obtain not only the detailed stability status at any grid node of a complex shear plane but also the global safety of the slope. Thus, it is helpful to thoroughly understand the mechanism of slope failure. Comparing with the result obtained through the limit equilibrium method, the presented method was proved to be more accurate and suitable for stability analysis of rock slope with a thin shear plane. The stability of a potentially unstable rock slope was analyzed based on the presented method at the end of this paper. The detailed local stability, global stability, and the potential failure mechanism were provided.

  6. Fatigue damage estimation using irregularity factor. First report, irregularity factor calculations for narrow and broadband random time histories

    Science.gov (United States)

    Susuki, I.

    1981-11-01

    The results of an analysis of the irregularity factors of stationary and Gaussian random processes which are generated by filtering the output of a pure or a band-limited white noise are presented. An ideal band pass filter, a trapezoidal filter, and a Butterworth type band pass filter were examined. It was found that the values of the irregularity factors were approximately equal among these filters if only the end-slopes were the same rates. As the band width of filters increases, irregularity factors increase monotonically and approach the respective constant values depending on the end-slopes. This implies that the noise characteristics relevant to the fatigue damage such as statistical aspects of the height of the rise and fall or the distribution of the peak values are not changed for a broad band random time history. It was also found that the effect of band limitation of input white noise on irregularity factors is negligibly small.

  7. Feedback Limiting the Coastal Response to Irregularities in Shelf Bathymetry

    Science.gov (United States)

    List, J. H.; Benedet, L.

    2007-12-01

    Observations and engineering studies have shown that non-uniform inner shelf bathymetry can influence longshore sediment transport gradients and create patterns of shoreline change. One classic example is from Grand Isle, Louisiana, where two offshore borrow pits caused two zones of shoreline accretion landward of the pits. In addition to anthropogenic cases, many natural situations exist in which irregularities in coastal planform are thought to result from offshore shoals or depressions. Recent studies using the hydrodynamic model Delft3D have successfully simulated the observed nearshore erosion and accretion patterns landward of an inner shelf borrow pit. An analysis of the momentum balance in a steady-state simulation has demonstrated that both alongshore pressure gradients (due to alongshore variations in wave setup) and radiation stress gradients (terms relevant to alongshore forcing) are important for forcing the initial pattern of nearshore sedimentation in response to the borrow pit. The response of the coast to non-uniform inner shelf bathymetry appears to be limited, however, because observed shoreline undulations are often rather subtle. (An exception may exist in the case of a very high angle wave climate.) Therefore, feedbacks in processes must exist such that growth of the shoreline salient itself modifies the transport processes in a way that limits further growth (assuming the perturbation in inner shelf bathymetry itself remains unchanged). Examination of the Delft3D momentum balance for an inner shelf pit test case demonstrates that after a certain degree of morphologic development the forcing associated with the well-known shoreline smoothing process (a.k.a., diffusion) counteracts the forcing associated with the inner shelf pit, producing a negative feedback which arrests further growth of the shoreline salient. These results provide insights into the physical processes that control shoreline changes behind inner shelf bathymetric anomalies (i

  8. Geostatistical regularization operators for geophysical inverse problems on irregular meshes

    Science.gov (United States)

    Jordi, C.; Doetsch, J.; Günther, T.; Schmelzbach, C.; Robertsson, J. OA

    2018-05-01

    Irregular meshes allow to include complicated subsurface structures into geophysical modelling and inverse problems. The non-uniqueness of these inverse problems requires appropriate regularization that can incorporate a priori information. However, defining regularization operators for irregular discretizations is not trivial. Different schemes for calculating smoothness operators on irregular meshes have been proposed. In contrast to classical regularization constraints that are only defined using the nearest neighbours of a cell, geostatistical operators include a larger neighbourhood around a particular cell. A correlation model defines the extent of the neighbourhood and allows to incorporate information about geological structures. We propose an approach to calculate geostatistical operators for inverse problems on irregular meshes by eigendecomposition of a covariance matrix that contains the a priori geological information. Using our approach, the calculation of the operator matrix becomes tractable for 3-D inverse problems on irregular meshes. We tested the performance of the geostatistical regularization operators and compared them against the results of anisotropic smoothing in inversions of 2-D surface synthetic electrical resistivity tomography (ERT) data as well as in the inversion of a realistic 3-D cross-well synthetic ERT scenario. The inversions of 2-D ERT and seismic traveltime field data with geostatistical regularization provide results that are in good accordance with the expected geology and thus facilitate their interpretation. In particular, for layered structures the geostatistical regularization provides geologically more plausible results compared to the anisotropic smoothness constraints.

  9. Total edge irregularity strength of (n,t)-kite graph

    Science.gov (United States)

    Winarsih, Tri; Indriati, Diari

    2018-04-01

    Let G(V, E) be a simple, connected, and undirected graph with vertex set V and edge set E. A total k-labeling is a map that carries vertices and edges of a graph G into a set of positive integer labels {1, 2, …, k}. An edge irregular total k-labeling λ :V(G)\\cup E(G)\\to \\{1,2,\\ldots,k\\} of a graph G is a labeling of vertices and edges of G in such a way that for any different edges e and f, weights wt(e) and wt(f) are distinct. The weight wt(e) of an edge e = xy is the sum of the labels of vertices x and y and the label of the edge e. The total edge irregularity strength of G, tes(G), is defined as the minimum k for which a graph G has an edge irregular total k-labeling. An (n, t)-kite graph consist of a cycle of length n with a t-edge path (the tail) attached to one vertex of a cycle. In this paper, we investigate the total edge irregularity strength of the (n, t)-kite graph, with n > 3 and t > 1. We obtain the total edge irregularity strength of the (n, t)-kite graph is tes((n, t)-kite) = \\lceil \\frac{n+t+2}{3}\\rceil .

  10. Irregular water supply, household usage and dengue: a bio-social study in the Brazilian Northeast.

    Science.gov (United States)

    Caprara, Andrea; Lima, José Wellington de Oliveira; Marinho, Alice Correia Pequeno; Calvasina, Paola Gondim; Landim, Lucyla Paes; Sommerfeld, Johannes

    2009-01-01

    Despite increased vector control efforts, dengue fever remains endemic in Fortaleza, Northeast Brazil, where sporadic epidemic outbreaks have occurred since 1986. Multiple factors affect vector ecology such as social policy, migration, urbanization, city water supply, garbage disposal and housing conditions, as well as community level understanding of the disease and related practices. This descriptive study used a multi-disciplinary approach that bridged anthropology and entomology. A multiple case study design was adopted to include research in six study areas, defined as blocks. The water supply is irregular in households from both under-privileged and privileged areas, however, clear differences exist. In the more privileged blocks, several homes are not connected to the public water system, but have a well and pump system and therefore irregularity of supply does not affect them. In households from under-privileged blocks, where the water supply is irregular, the frequent use of water containers such as water tanks, cisterns, barrels and pots, creates environmental conditions with a greater number of breeding areas. In under-privileged homes, there are more possible breeding areas and environmental conditions that may improve the chances of Aedes aegypti survival.

  11. On the Automatic Parallelization of Sparse and Irregular Fortran Programs

    Directory of Open Access Journals (Sweden)

    Yuan Lin

    1999-01-01

    Full Text Available Automatic parallelization is usually believed to be less effective at exploiting implicit parallelism in sparse/irregular programs than in their dense/regular counterparts. However, not much is really known because there have been few research reports on this topic. In this work, we have studied the possibility of using an automatic parallelizing compiler to detect the parallelism in sparse/irregular programs. The study with a collection of sparse/irregular programs led us to some common loop patterns. Based on these patterns new techniques were derived that produced good speedups when manually applied to our benchmark codes. More importantly, these parallelization methods can be implemented in a parallelizing compiler and can be applied automatically.

  12. Measurement of Dynamic Friction Coefficient on the Irregular Free Surface

    International Nuclear Information System (INIS)

    Yeom, S. H.; Seo, K. S.; Lee, J. H.; Lee, K. H.

    2007-01-01

    A spent fuel storage cask must be estimated for a structural integrity when an earthquake occurs because it freely stands on ground surface without a restriction condition. Usually the integrity estimation for a seismic load is performed by a FEM analysis, the friction coefficient for a standing surface is an important parameter in seismic analysis when a sliding happens. When a storage cask is placed on an irregular ground surface, measuring a friction coefficient of an irregular surface is very difficult because the friction coefficient is affected by the surface condition. In this research, dynamic friction coefficients on the irregular surfaces between a concrete cylinder block and a flat concrete slab are measured with two methods by one direction actuator

  13. NEOWISE: OBSERVATIONS OF THE IRREGULAR SATELLITES OF JUPITER AND SATURN

    Energy Technology Data Exchange (ETDEWEB)

    Grav, T. [Planetary Science Institute, Tucson, AZ 85719 (United States); Bauer, J. M.; Mainzer, A. K.; Masiero, J. R.; Sonnett, S.; Kramer, E. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Nugent, C. R.; Cutri, R. M., E-mail: tgrav@psi.edu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2015-08-10

    We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE data set. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer solar system, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.

  14. Bottomside sinusoidal irregularities in the equatorial F region

    Science.gov (United States)

    Valladares, C. E.; Hanson, W. B.; Mcclure, J. P.; Cragin, B. L.

    1983-01-01

    By using the Ogo 6 satellite, McClure and Hanson (1973) have discovered sinusoidal irregularities in the equatorial F region ion number density. In the present investigation, a description is provided of the properties of a distinct category of sinusoidal irregularities found in equatorial data from the AE-C and AE-E satellites. The observed scale sizes vary from about 300 m to 3 km in the direction perpendicular to B, overlapping with and extending the range observed by using Ogo 6. Attention is given to low and high resolution data, a comparison with Huancayo ionograms, the confinement of 'bottomside sinusoidal' (BSS) irregularities essentially to the bottomside of the F layer, spectral characteristics, and BSS, scintillation, and ionosonde observations.

  15. Irregular flowering patterns in terrestrial orchids: theories vs. empirical data

    Directory of Open Access Journals (Sweden)

    P. Kindlmann

    2001-11-01

    Full Text Available Empirical data on many species of terrestrial orchids suggest that their between-year flowering pattern is extremely irregular and unpredictable. A long search for the reason has hitherto proved inconclusive. Here we summarise and critically review the hypotheses that were put forward as explanations of this phenomenon: irregular flowering was attributed to costs associated with sexual reproduction, to herbivory, or to the chaotic behaviour of the system represented by difference equations describing growth of the vegetative and reproductive organs. None of these seems to explain fully the events of a transition from flowering one year to sterility or absence the next year. Data on the seasonal growth of leaves and inflorescence of two terrestrial orchid species, Epipactis albensis and Dactylorhiza fuchsii and our previous results are then used here to fill gaps in what has been published until now and to test alternative explanations of the irregular flowering patterns of orchids.

  16. Track Irregularity Time Series Analysis and Trend Forecasting

    Directory of Open Access Journals (Sweden)

    Jia Chaolong

    2012-01-01

    Full Text Available The combination of linear and nonlinear methods is widely used in the prediction of time series data. This paper analyzes track irregularity time series data by using gray incidence degree models and methods of data transformation, trying to find the connotative relationship between the time series data. In this paper, GM (1,1 is based on first-order, single variable linear differential equations; after an adaptive improvement and error correction, it is used to predict the long-term changing trend of track irregularity at a fixed measuring point; the stochastic linear AR, Kalman filtering model, and artificial neural network model are applied to predict the short-term changing trend of track irregularity at unit section. Both long-term and short-term changes prove that the model is effective and can achieve the expected accuracy.

  17. Exploring Manycore Multinode Systems for Irregular Applications with FPGA Prototyping

    Energy Technology Data Exchange (ETDEWEB)

    Ceriani, Marco; Palermo, Gianluca; Secchi, Simone; Tumeo, Antonino; Villa, Oreste

    2013-04-29

    We present a prototype of a multi-core architecture implemented on FPGA, designed to enable efficient execution of irregular applications on distributed shared memory machines, while maintaining high performance on regular workloads. The architecture is composed of off-the-shelf soft-core cores, local interconnection and memory interface, integrated with custom components that optimize it for irregular applications. It relies on three key elements: a global address space, multithreading, and fine-grained synchronization. Global addresses are scrambled to reduce the formation of network hot-spots, while the latency of the transactions is covered by integrating an hardware scheduler within the custom load/store buffers to take advantage from the availability of multiple executions threads, increasing the efficiency in a transparent way to the application. We evaluated a dual node system irregular kernels showing scalability in the number of cores and threads.

  18. Deterministic Approach to Detect Heart Sound Irregularities

    Directory of Open Access Journals (Sweden)

    Richard Mengko

    2017-07-01

    Full Text Available A new method to detect heart sound that does not require machine learning is proposed. The heart sound is a time series event which is generated by the heart mechanical system. From the analysis of heart sound S-transform and the understanding of how heart works, it can be deducted that each heart sound component has unique properties in terms of timing, frequency, and amplitude. Based on these facts, a deterministic method can be designed to identify each heart sound components. The recorded heart sound then can be printed with each component correctly labeled. This greatly help the physician to diagnose the heart problem. The result shows that most known heart sounds were successfully detected. There are some murmur cases where the detection failed. This can be improved by adding more heuristics including setting some initial parameters such as noise threshold accurately, taking into account the recording equipment and also the environmental condition. It is expected that this method can be integrated into an electronic stethoscope biomedical system.

  19. Propagation and scattering of electromagnetic waves by the ionospheric irregularities

    International Nuclear Information System (INIS)

    Ho, A.Y.; Kuo, S.P.; Lee, M.C.

    1993-01-01

    The problem of wave propagation and scattering in the ionosphere is particularly important in the areas of communications, remote-sensing and detection. The ionosphere is often perturbed with coherently structured (quasiperiodic) density irregularities. Experimental observations suggest that these irregularities could give rise to significant ionospheric effect on wave propagation such as causing spread-F of the probing HF sounding signals and scintillation of beacon satellite signals. It was show by the latter that scintillation index S 4 ∼ 0.5 and may be as high as 0.8. In this work a quasi-particle theory is developed to study the scintillation phenomenon. A Wigner distribution function for the wave intensity in the (k,r) space is introduced and its governing equation is derived with an effective collision term giving rise to the attenuation and scattering of the wave. This kinetic equation leads to a hierarchy of moment equations in r space. This systems of equations is then truncated to the second moment which is equivalent to assuming a cold quasi-particle distribution In this analysis, the irregularities are modeled as a two dimensional density modulation on an uniform background plasma. The analysis shows that this two dimensional density grating, effectively modulates the intensity of the beacon satellite signals. This spatial modulation of the wave intensity is converted into time modulation due to the drift of the ionospheric irregularities, which then contributes to the scintillation of the beacon satellite signals. Using the proper plasma parameters and equatorial measured data of irregularities, it is shown that the scintillation index defined by S4=( 2 >- 2 )/ 2 where stands for spatial average over an irregularity wavelength is in the range of the experimentally detected values

  20. Irregular Shaped Building Design Optimization with Building Information Modelling

    Directory of Open Access Journals (Sweden)

    Lee Xia Sheng

    2016-01-01

    Full Text Available This research is to recognise the function of Building Information Modelling (BIM in design optimization for irregular shaped buildings. The study focuses on a conceptual irregular shaped “twisted” building design similar to some existing sculpture-like architectures. Form and function are the two most important aspects of new buildings, which are becoming more sophisticated as parts of equally sophisticated “systems” that we are living in. Nowadays, it is common to have irregular shaped or sculpture-like buildings which are very different when compared to regular buildings. Construction industry stakeholders are facing stiff challenges in many aspects such as buildability, cost effectiveness, delivery time and facility management when dealing with irregular shaped building projects. Building Information Modelling (BIM is being utilized to enable architects, engineers and constructors to gain improved visualization for irregular shaped buildings; this has a purpose of identifying critical issues before initiating physical construction work. In this study, three variations of design options differing in rotating angle: 30 degrees, 60 degrees and 90 degrees are created to conduct quantifiable comparisons. Discussions are focused on three major aspects including structural planning, usable building space, and structural constructability. This research concludes that Building Information Modelling is instrumental in facilitating design optimization for irregular shaped building. In the process of comparing different design variations, instead of just giving “yes or no” type of response, stakeholders can now easily visualize, evaluate and decide to achieve the right balance based on their own criteria. Therefore, construction project stakeholders are empowered with superior evaluation and decision making capability.

  1. Low frequency sound reproduction in irregular rooms using CABS (Control Acoustic Bass System)

    DEFF Research Database (Denmark)

    Celestinos, Adrian; Nielsen, Sofus Birkedal

    2011-01-01

    of an irregular room model using the FDTD (Finite Difference Time Domain) method has been presented. CABS has been simulated in the irregular room model. Measurements of CABS in a real irregular room have been performed. The performance of CABS was affected by the irregular shape of the room due to the corner...

  2. Characterizing spontaneous irregular behavior in coupled map lattices

    International Nuclear Information System (INIS)

    Dobyns, York; Atmanspacher, Harald

    2005-01-01

    Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties

  3. Characterizing spontaneous irregular behavior in coupled map lattices

    Energy Technology Data Exchange (ETDEWEB)

    Dobyns, York [PEAR, Princeton University Princeton, NJ 08544-5263 (United States); Atmanspacher, Harald [Institut fuer Grenzgebiete der Psychologie und Psychohygiene Wilhelmstrasse 3a, Freiburg 79098 (Germany)]. E-mail: haa@igpp.de

    2005-04-01

    Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties.

  4. [Artificial cycle therapy of acupuncture and moxibustion for irregular menstruation].

    Science.gov (United States)

    Wu, Jie; Yang, Lijie; Chen, Yajie; Li, Qing; Chen, Lin

    2015-03-01

    Through the discussion on TCM physiological characters of females in follicular, ovulatory, luteal and menstrual phases and treatment principles, the clinical application of artificial cycle therapy of acupuncture and moxibustion was introduced for irregular menstruation and the typical cases were attached. It is suggested that the menstrual cycle follows the growth-consumption rule of yin, yang, qi and blood. The corresponding treatment principles should be applied in accordance with the change rule of menstrual cycle. Hence, it is worth to adopt the artificial cycle therapy of acupuncture and moxibustion for irregular menstruation in clinical application.

  5. Uniform irradiation of irregularly shaped cavities for photodynamic therapy.

    Science.gov (United States)

    Rem, A I; van Gemert, M J; van der Meulen, F W; Gijsbers, G H; Beek, J F

    1997-03-01

    It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a cubical box, a sphere, a cylinder and a 'bottle-neck' geometry have been investigated experimentally and the results have been compared with computed light distributions obtained using the 'radiosity method'. A high reflection coefficient of the mould and the best uniform direct irradiance possible on the inside of the mould were found to be important determinants for achieving a uniform light distribution.

  6. Natural selection drives the fine-scale divergence of a coevolutionary arms race involving a long-mouthed weevil and its obligate host plant

    Directory of Open Access Journals (Sweden)

    Toju Hirokazu

    2009-01-01

    Full Text Available Abstract Background One of the major recent advances in evolutionary biology is the recognition that evolutionary interactions between species are substantially differentiated among geographic populations. To date, several authors have revealed natural selection pressures mediating the geographically-divergent processes of coevolution. How local, then, is the geographic structuring of natural selection in coevolutionary systems? Results I examined the spatial scale of a "geographic selection mosaic," focusing on a system involving a seed-predatory insect, the camellia weevil (Curculio camelliae, and its host plant, the Japanese camellia (Camellia japonica. In this system, female weevils excavate camellia fruits with their extremely-long mouthparts to lay eggs into seeds, while camellia seeds are protected by thick pericarps. Quantitative evaluation of natural selection demonstrated that thicker camellia pericarps are significantly favored in some, but not all, populations within a small island (Yakushima Island, Japan; diameter ca. 30 km. At the extreme, camellia populations separated by only several kilometers were subject to different selection pressures. Interestingly, in a population with the thickest pericarps, camellia individuals with intermediate pericarp thickness had relatively high fitness when the potential costs of producing thick pericarps were considered. Also importantly, some parameters of the weevil - camellia interaction such as the severity of seed infestation showed clines along temperature, suggesting the effects of climate on the fine-scale geographic differentiation of the coevolutionary processes. Conclusion These results show that natural selection can drive the geographic differentiation of interspecific interactions at surprisingly small spatial scales. Future studies should reveal the evolutionary/ecological outcomes of the "fine scale geographic mosaics" in biological communities.

  7. General Lines of Disregard for the Legal Personality on Irregular Dissolution the Company

    Directory of Open Access Journals (Sweden)

    Fábio Augusto Barcelos Moreira Corrêa

    2016-12-01

    Full Text Available This article will analyze the Institute of disregard for the legal personality in situations involving irregular dissolution the limited liability company, in light of the jurisprudence of the Superior Court Tribunal. We highlight the impact that new code of Civil procedure will provide for analysis to safeguard the autonomy of assets of the legal person, as well as the guarantee of due process and of ample defense, directly impacting on business law. The analysis aims to contribute to the understanding of the Institute, and the systematic procedure. Adopting the dialectical methodology and criticism.

  8. Runtime buffer management to improve the performance in irregular ...

    Indian Academy of Sciences (India)

    S¯adhan¯a Vol. 40, Part 4, June 2015, pp. 1117–1137. c Indian Academy of Sciences. Runtime buffer management to improve the performance in irregular Network-on-Chip architecture. UMAMAHESWARI S1,∗, MEGANATHAN D2 and. RAJA PAUL PERINBAM J3. 1Department of Information Technology, Anna University, ...

  9. The regularized monotonicity method: detecting irregular indefinite inclusions

    DEFF Research Database (Denmark)

    Garde, Henrik; Staboulis, Stratos

    2018-01-01

    inclusions, where the conductivity distribution has both more and less conductive parts relative to the background conductivity; one such method is the monotonicity method of Harrach, Seo, and Ullrich. We formulate the method for irregular indefinite inclusions, meaning that we make no regularity assumptions...

  10. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    NARCIS (Netherlands)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-01-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of

  11. Interagency Cooperation for Irregular Warfare at the Combatant Command

    Science.gov (United States)

    2009-01-01

    enemy’s command capability.16 Salamoni argued that the term “irregular warfare” belies an ethnocentric perspective of conflict that will limit military...duty military staffing to form the nucleus of the organization, which would receive augmentation from additional assigned reservists and interagency

  12. Convection-diffusion lattice Boltzmann scheme for irregular lattices

    NARCIS (Netherlands)

    Sman, van der R.G.M.; Ernst, M.H.

    2000-01-01

    In this paper, a lattice Boltzmann (LB) scheme for convection diffusion on irregular lattices is presented, which is free of any interpolation or coarse graining step. The scheme is derived using the axioma that the velocity moments of the equilibrium distribution equal those of the

  13. Swiveling Lathe Jaw Concept for Holding Irregular Pieces

    Science.gov (United States)

    David, J.

    1966-01-01

    Clamp holds irregularly shaped pieces in lathe chuck without damage and eliminates excessive time in selecting optimum mounting. Interchangeable jaws ride in standard jaw slots but swivel so that the jaw face bears evenly against the workpiece regardless of contour. The jaws can be used on both engine and turret lathes.

  14. Why type 2 supernovae do not explode in irregular galaxies

    International Nuclear Information System (INIS)

    Shklovskij, I.S.

    1984-01-01

    The conclusion is drawn that reason for an absence of type 2 supernovae explosions in irregular galaxies is their peculiar chemical composition. The observed lack of stellar wind from massive hot giants is due to relatively low heavy element abundance. For this reason evolving massive stars do not form an extended dense envelopes that is a necessary condition for the type 2 supernova phenomenon

  15. First stellar abundances in the dwarf irregular galaxy Sextans A

    NARCIS (Netherlands)

    Kaufer, A; Venn, KA; Tolstoy, E; Pinte, C; Kudritzki, RP

    We present the abundance analyses of three isolated A-type supergiant stars in the dwarf irregular galaxy Sextans A (= DDO 75) from high-resolution spectra obtained with the Ultraviolet-Visual Echelle Spectrograph (UVES) on the Kueyen telescope (UT2) of the ESO Very Large Telescope (VLT). Detailed

  16. Spectral element method for wave propagation on irregular domains

    Indian Academy of Sciences (India)

    Yan Hui Geng

    2018-03-14

    Mar 14, 2018 ... Abstract. A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the ...

  17. On the Total Edge Irregularity Strength of Generalized Butterfly Graph

    Science.gov (United States)

    Dwi Wahyuna, Hafidhyah; Indriati, Diari

    2018-04-01

    Let G(V, E) be a connected, simple, and undirected graph with vertex set V and edge set E. A total k-labeling is a map that carries vertices and edges of a graph G into a set of positive integer labels {1, 2, …, k}. An edge irregular total k-labeling λ: V(G) ∪ E(G) → {1, 2, …, k} of a graph G is a total k-labeling such that the weights calculated for all edges are distinct. The weight of an edge uv in G, denoted by wt(uv), is defined as the sum of the label of u, the label of v, and the label of uv. The total edge irregularity strength of G, denoted by tes(G), is the minimum value of the largest label k over all such edge irregular total k-labelings. A generalized butterfly graph, BFn , obtained by inserting vertices to every wing with assumption that sum of inserting vertices to every wing are same then it has 2n + 1 vertices and 4n ‑ 2 edges. In this paper, we investigate the total edge irregularity strength of generalized butterfly graph, BFn , for n > 2. The result is tes(B{F}n)=\\lceil \\frac{4n}{3}\\rceil .

  18. On a new process for cusp irregularity production

    Directory of Open Access Journals (Sweden)

    H. C. Carlson

    2008-09-01

    Full Text Available Two plasma instability mechanisms were thought until 2007 to dominate the formation of plasma irregularities in the F region high latitude and polar ionosphere; the gradient-drift driven instability, and the velocity-shear driven instability. The former mechanism was accepted as accounting for plasma structuring in polar cap patches, the latter for plasma structuring in polar cap sun aligned arcs. Recent work has established the need to replace this view of the past two decades with a new patch plasma structuring process (not a new mechanism, whereby shear-driven instabilities first rapidly structure the entering plasma, after which gradient drift instabilities build on these large "seed" irregularities. Correct modeling of cusp and early polar cap patch structuring will not be accomplished without allowing for this compound process. This compound process explains several previously unexplained characteristics of cusp and early polar cap patch irregularities. Here we introduce additional data, coincident in time and space, to extend that work to smaller irregularity scale sizes and relate it to the structured cusp current system.

  19. Irregular ionization and scintillation of the ionosphere in equator region

    International Nuclear Information System (INIS)

    Shinno, Kenji

    1974-01-01

    The latest studies on the scintillation in satellite communication and its related irregularities of ionosphere are reviewed. They were made clear by means of spread-F, the direct measurement with scientific satellites, VHF radar observation, and radio wave propagation in equator region. The fundamental occurrence mechanism may be instability of plasma caused by the interaction of movement of neutral atmosphere and magnetic field. Comparison of the main characteristics of scintillation, namely the dependence on region, solar activity, season, local time, geomagnetic activity, movement in ionosphere, scattering source, frequency and transmission mode, was made and the correlation among spread-F, TEP and scintillation was summarized. The latest principal studies were the observations made by Intelsat and by ATS. Scintillation of Syncom-3 and Intelsat-II-F2 and spread-F by ionosphere observation were compared by Huang. It is reasonable to consider that the occurrence of scintillation is caused by the irregularities in ionosphere which are particular in equator region, because of the similar characteristics of spread-F and VHF propagation in the equator region. These three phenomena may occur in relation to the irregularities of ionosphere. Interpretation of spread-F and the abnormal propagation wave across the equator are given. The study using VHF radar and the movement of irregular ionization by the direct observation with artificial satellites are reviewd. (Iwakiri, K.)

  20. Third-order theory for multi-directional irregular waves

    DEFF Research Database (Denmark)

    Madsen, Per A.; Fuhrman, David R.

    2012-01-01

    A new third-order solution for multi-directional irregular water waves in finite water depth is presented. The solution includes explicit expressions for the surface elevation, the amplitude dispersion and the vertical variation of the velocity potential. Expressions for the velocity potential at...

  1. Irregular menses: an independent risk factor for gestational diabetes mellitus.

    Science.gov (United States)

    Haver, Mary Claire; Locksmith, Gregory J; Emmet, Emily

    2003-05-01

    Our purpose was to determine whether a history of irregular menses predicts gestational diabetes mellitus independently of traditional risk factors. We analyzed demographic characteristics, body mass index, and menstrual history of 85 pregnant women with gestational diabetes mellitus and compared them with 85 systematically selected control subjects who were matched for age, race, and delivery year. Subjects with pregestational diabetes mellitus, previous gestational diabetes mellitus, family history of diabetes mellitus, weight >200 pounds, previous macrosomic infants, or previous stillbirth were excluded. Demographic characteristics between case and control groups were similar. Mean body mass index was higher among cases (26.5 kg/m(2)) versus control subjects (24.5 kg/m(2), P =.004). Irregular cycles were more prevalent in the cases (24% vs 7%, P =.006). With the use of body mass index as a stratification factor, menstrual irregularity maintained a strong association with gestational diabetes mellitus (P =.014). A history of irregular menstrual cycles was a significant independent predictor of gestational diabetes mellitus. If selective screening is implemented for gestational diabetes mellitus, such history should be considered in the decision of whom to test.

  2. Spectral element method for wave propagation on irregular domains

    Indian Academy of Sciences (India)

    A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the physical space are ...

  3. Characteristics of low latitude ionospheric E-region irregularities ...

    Indian Academy of Sciences (India)

    154°E, dip angle = 37.3°, sub-ionospheric dip = 34°) have been analyzed to study the behaviour of ionospheric E-region irregularities during the active solar and magnetic periods. The autocorrelation functions, power spectral densities, signal de-correlation times are computed to study the temporal features of ionospheric ...

  4. Classical limit of irregular blocks and Mathieu functions

    International Nuclear Information System (INIS)

    Piątek, Marcin; Pietrykowski, Artur R.

    2016-01-01

    The Nekrasov-Shatashvili limit of the N = 2 SU(2) pure gauge (Ω-deformed) super Yang-Mills theory encodes the information about the spectrum of the Mathieu operator. On the other hand, the Mathieu equation emerges entirely within the frame of two-dimensional conformal field theory (2d CFT) as the classical limit of the null vector decoupling equation for some degenerate irregular block. Therefore, it seems to be possible to investigate the spectrum of the Mathieu operator employing the techniques of 2d CFT. To exploit this strategy, a full correspondence between the Mathieu equation and its realization within 2d CFT has to be established. In our previous paper http://dx.doi.org/10.1007/JHEP12(2014)032, we have found that the expression of the Mathieu eigenvalue given in terms of the classical irregular block exactly coincides with the well known weak coupling expansion of this eigenvalue in the case in which the auxiliary parameter is the noninteger Floquet exponent. In the present work we verify that the formula for the corresponding eigenfunction obtained from the irregular block reproduces the so-called Mathieu exponent from which the noninteger order elliptic cosine and sine functions may be constructed. The derivation of the Mathieu equation within the formalism of 2d CFT is based on conjectures concerning the asymptotic behaviour of irregular blocks in the classical limit. A proof of these hypotheses is sketched. Finally, we speculate on how it could be possible to use the methods of 2d CFT in order to get from the irregular block the eigenvalues of the Mathieu operator in other regions of the coupling constant.

  5. Comparison of correlation analysis techniques for irregularly sampled time series

    Directory of Open Access Journals (Sweden)

    K. Rehfeld

    2011-06-01

    Full Text Available Geoscientific measurements often provide time series with irregular time sampling, requiring either data reconstruction (interpolation or sophisticated methods to handle irregular sampling. We compare the linear interpolation technique and different approaches for analyzing the correlation functions and persistence of irregularly sampled time series, as Lomb-Scargle Fourier transformation and kernel-based methods. In a thorough benchmark test we investigate the performance of these techniques.

    All methods have comparable root mean square errors (RMSEs for low skewness of the inter-observation time distribution. For high skewness, very irregular data, interpolation bias and RMSE increase strongly. We find a 40 % lower RMSE for the lag-1 autocorrelation function (ACF for the Gaussian kernel method vs. the linear interpolation scheme,in the analysis of highly irregular time series. For the cross correlation function (CCF the RMSE is then lower by 60 %. The application of the Lomb-Scargle technique gave results comparable to the kernel methods for the univariate, but poorer results in the bivariate case. Especially the high-frequency components of the signal, where classical methods show a strong bias in ACF and CCF magnitude, are preserved when using the kernel methods.

    We illustrate the performances of interpolation vs. Gaussian kernel method by applying both to paleo-data from four locations, reflecting late Holocene Asian monsoon variability as derived from speleothem δ18O measurements. Cross correlation results are similar for both methods, which we attribute to the long time scales of the common variability. The persistence time (memory is strongly overestimated when using the standard, interpolation-based, approach. Hence, the Gaussian kernel is a reliable and more robust estimator with significant advantages compared to other techniques and suitable for large scale application to paleo-data.

  6. Wettability measurements of irregular shapes with Wilhelmy plate method

    Science.gov (United States)

    Park, Jaehyung; Pasaogullari, Ugur; Bonville, Leonard

    2018-01-01

    One of the most accurate methods for measuring the dynamic contact angle of liquids on solid surfaces is the Wilhelmy plate method. This method generally requires the use of rectangular samples having a constant perimeter in the liquid during advancing and receding cycles. A new formulation based on the Wilhelmy force balance equation to determine the contact angle for plate samples with irregular shapes has been developed. This method employs a profile plot obtained from an optical image to determine the perimeter (i.e. wetted length) of the sample as a function of the immersion depth. The raw force data measured by the force tensiometer is manipulated using the profile plot and the Wilhelmy equation to determine the wetting force and consequently advancing and the receding contact angle. This method is verified with both triangular and irregular PTFE samples in water, and measured contact angles are in good agreement with results from conventional regular shaped samples with a constant perimeter.

  7. Rocket measurements of electron density irregularities during MAC/SINE

    Science.gov (United States)

    Ulwick, J. C.

    1989-01-01

    Four Super Arcas rockets were launched at the Andoya Rocket Range, Norway, as part of the MAC/SINE campaign to measure electron density irregularities with high spatial resolution in the cold summer polar mesosphere. They were launched as part of two salvos: the turbulent/gravity wave salvo (3 rockets) and the EISCAT/SOUSY radar salvo (one rocket). In both salvos meteorological rockets, measuring temperature and winds, were also launched and the SOUSY radar, located near the launch site, measured mesospheric turbulence. Electron density irregularities and strong gradients were measured by the rocket probes in the region of most intense backscatter observed by the radar. The electron density profiles (8 to 4 on ascent and 4 on descent) show very different characteristics in the peak scattering region and show marked spatial and temporal variability. These data are intercompared and discussed.

  8. The scholarly rebellion of the early Baker Street Irregulars

    Directory of Open Access Journals (Sweden)

    George Mills

    2017-03-01

    Full Text Available This work provides and analyzes an early institutional history of the pioneering Sherlock Holmes American fan club, the Baker Street Irregulars (BSI. Using the publications and records of these devoted Sherlockians, I track the BSI's development from a speakeasy gathering in 1934 to a national organization by the mid-1940s. This growth was built on a foundation of Victorian nostalgia and playful humor. Yet at the same time the members of the Irregulars took their fandom seriously, producing Sherlockian scholarship and creating an infrastructure of journals, conferences, and credentialing that directly mimicked the academy. They positioned themselves in contrast to prevailing scholarly practices of the period, such as New Criticism. I trace both how their fan practices developed over time and how this conflict with the academy led to many of the BSI's defining characteristics.

  9. Constructing C1 Continuous Surface on Irregular Quad Meshes

    Institute of Scientific and Technical Information of China (English)

    HE Jun; GUO Qiang

    2013-01-01

    A new method is proposed for surface construction on irregular quad meshes as extensions to uniform B-spline surfaces. Given a number of control points, which form a regular or irregular quad mesh, a weight function is constructed for each control point. The weight function is defined on a local domain and is C1 continuous. Then the whole surface is constructed by the weighted combination of all the control points. The property of the new method is that the surface is defined by piecewise C1 bi-cubic rational parametric polynomial with each quad face. It is an extension to uniform B-spline surfaces in the sense that its definition is an analogy of the B-spline surface, and it produces a uniform bi-cubic B-spline surface if the control mesh is a regular quad mesh. Examples produced by the new method are also included.

  10. Conflict Without Casualties: Non-Lethal Weapons in Irregular Warfare

    Science.gov (United States)

    2007-09-01

    the body,” and the Geneva Protocol of 1925, bans the use of chemical and biological weapons .11 On 8 April 1975, President Ford issued Executive...E Funding – PE 63851M) (accessed 15 December 2006). The American Journal of Bioethics . “Medical Ethics and Non-Lethal Weapons .” Bioethics.net...CASUALTIES: NON-LETHAL WEAPONS IN IRREGULAR WARFARE by Richard L. Scott September 2007 Thesis Advisor: Robert McNab Second Reader

  11. Active Absorption of Irregular Gravity Waves in BEM-Models

    DEFF Research Database (Denmark)

    Brorsen, Michael; Frigaard, Peter

    1992-01-01

    The boundary element method is applied to the computation of irregular gravity waves. The boundary conditions at the open boundaries are obtained by a digital filtering technique, where the surface elevations in front of the open boundary are filtered numerically yielding the velocity to be presc...... to be prescribed at the boundary. By numerical examples it is shown that well designed filters can reduce the wave reflection to a few per cent over a frequency range corresponding to a Jonswap spectrum....

  12. Using Little's Irregularity Index in orthodontics: outdated and inaccurate?

    LENUS (Irish Health Repository)

    Macauley, Donal

    2012-12-01

    Little\\'s Irregularity Index (LII) was devised to objectively score mandibular incisor alignment for epidemiological studies but has been extended to assess the relative performance of orthodontic brackets, retainer or treatment modalities. Our aim was to examine the repeatability and precision of LII measurements of four independent examiners on the maxillary arch of orthodontic patients. The hypothesis was that the reproducibility of individual contact point displacement measurements, used to calculate the LII score, are inappropriate.

  13. Computing Homology Group Generators of Images Using Irregular Graph Pyramids

    OpenAIRE

    Peltier , Samuel; Ion , Adrian; Haxhimusa , Yll; Kropatsch , Walter; Damiand , Guillaume

    2007-01-01

    International audience; We introduce a method for computing homology groups and their generators of a 2D image, using a hierarchical structure i.e. irregular graph pyramid. Starting from an image, a hierarchy of the image is built, by two operations that preserve homology of each region. Instead of computing homology generators in the base where the number of entities (cells) is large, we first reduce the number of cells by a graph pyramid. Then homology generators are computed efficiently on...

  14. Analysis of irregular opacities of silicosis using computed tomography

    International Nuclear Information System (INIS)

    Maeda, Atsushi; Shida, Hisao; Chiyotani, Keizo; Saito, Kenichi; Mishina, Michihito

    1983-01-01

    Classification in used to codify Chest CT images of abnormalities of the lung in a simple reproducible manner. Simbols to record CT features of importance are listed. We applied CT to 92 cases of silicosis and roentgenological analysis was performed. Bullae, honeycombing, cavity, emphysema, pleural thickning and calcification were more clearly demonstrated in CT images than routine chest roentgenograms. Irregular opacities were considered to be a combined profusion of small round and streak or strand. (author)

  15. Evaluation of irregular menses in perimenarcheal girls: a pilot study.

    Science.gov (United States)

    Browner-Elhanan, Karen J; Epstein, Jonathan; Alderman, Elizabeth M

    2003-12-01

    Acyclic vaginal bleeding in girls within three years of menarche is most commonly attributed to an immature hypothalamic-pituitary-ovarian axis. Assuming this diagnosis may preclude the practitioner from performing more definitive studies and thereby diagnosing other, treatable causes of menstrual irregularities. A retrospective chart review of 178 girls presenting to an inner-city hospital-based adolescent clinic within three years of menarche was performed. Personal and family medical and menarcheal history was assessed, and findings on physical and laboratory examination performed were evaluated. Of the 178 girls still perimenarcheal at presentation, 47 were the focus of this study. Of these, 39 had no significant findings on physical examination, while 3 had signs of functional ovarian hyperandrogenism (FOH) including obesity, hirsutism, and moderate acne with corresponding LH/FSH ratios>3, although pelvic ultrasound examination revealed normal ovaries. Four of the 39 patients with normal physical exams had LH/FSH testing done, and 1 of the 4 had an abnormal LH/FSH ratio, indicating possible FOH. Two of the 47 patients were pregnant. Other laboratory abnormalities included microcytic, hypochromic anemia in patients, and an elevated Erythrocyte Sedimentation Rate in a patient later diagnosed with a rheumatologic disorder. Those perimenarcheal girls presenting with irregular menses and findings including obesity, acne, or pallor, were likely to have treatable causes of menstrual irregularities. In one of the four girls with a normal physical examination, hormonal testing indicated possible FOH, thus suggesting that hormonal evaluation of perimenarcheal girls with menstrual irregularities may be justified, as it may reveal previously unsuspected pathology.

  16. Backscatter measurements of 11-cm equatorial spread-F irregularities

    International Nuclear Information System (INIS)

    Tsunoda, R.T.

    1980-01-01

    In the equatorial F-region ionosphere, a turbulent cascade process has been found to exist that extends from irregularity spatial wavelengths longer than tens of kilometers down to wavelengths as short as 36 cm. To investigate the small-scale regime of wavelengths less than 36 cm, an equatorial radar experiment was conducted using a frequency of 1320 MHz that corresponds to an irregularity wavelength of 11 cm. The first observations of radar backscatter from 11-cm field-aligned irregularities (FAI) are described. These measurements extend the spatial wavelength regime of F-region FAI to lengths that approach both electron gyroradius and the Debye length. Agreement of these results with the theory of high-frequency drift waves suggests that these observations may be unique to the equatorial ionosphere. That is, the requirement of low electron densities for which the theroy calls may preclude the existence of 11-cm FAI elsewhere in the F-region ionosphere, except in equatorial plasma bubbles

  17. [Comparision of Different Methods of Area Measurement in Irregular Scar].

    Science.gov (United States)

    Ran, D; Li, W J; Sun, Q G; Li, J Q; Xia, Q

    2016-10-01

    To determine a measurement standard of irregular scar area by comparing the advantages and disadvantages of different measurement methods in measuring same irregular scar area. Irregular scar area was scanned by digital scanning and measured by coordinate reading method, AutoCAD pixel method, Photoshop lasso pixel method, Photoshop magic bar filled pixel method and Foxit PDF reading software, and some aspects of these methods such as measurement time, repeatability, whether could be recorded and whether could be traced were compared and analyzed. There was no significant difference in the scar areas by the measurement methods above. However, there was statistical difference in the measurement time and repeatability by one or multi performers and only Foxit PDF reading software could be traced back. The methods above can be used for measuring scar area, but each one has its advantages and disadvantages. It is necessary to develop new measurement software for forensic identification. Copyright© by the Editorial Department of Journal of Forensic Medicine

  18. Seismic performance for vertical geometric irregularity frame structures

    Science.gov (United States)

    Ismail, R.; Mahmud, N. A.; Ishak, I. S.

    2018-04-01

    This research highlights the result of vertical geometric irregularity frame structures. The aid of finite element analysis software, LUSAS was used to analyse seismic performance by focusing particularly on type of irregular frame on the differences in height floors and continued in the middle of the building. Malaysia’s building structures were affected once the earthquake took place in the neighbouring country such as Indonesia (Sumatera Island). In Malaysia, concrete is widely used in building construction and limited tension resistance to prevent it. Analysing structural behavior with horizontal and vertical static load is commonly analyses by using the Plane Frame Analysis. The case study of this research is to determine the stress and displacement in the seismic response under this type of irregular frame structures. This study is based on seven-storey building of Clinical Training Centre located in Sungai Buloh, Selayang, Selangor. Since the largest earthquake occurs in Acheh, Indonesia on December 26, 2004, the data was recorded and used in conducting this research. The result of stress and displacement using IMPlus seismic analysis in LUSAS Modeller Software under the seismic response of a formwork frame system states that the building is safe to withstand the ground and in good condition under the variation of seismic performance.

  19. Irregular analytical errors in diagnostic testing - a novel concept.

    Science.gov (United States)

    Vogeser, Michael; Seger, Christoph

    2018-02-23

    In laboratory medicine, routine periodic analyses for internal and external quality control measurements interpreted by statistical methods are mandatory for batch clearance. Data analysis of these process-oriented measurements allows for insight into random analytical variation and systematic calibration bias over time. However, in such a setting, any individual sample is not under individual quality control. The quality control measurements act only at the batch level. Quantitative or qualitative data derived for many effects and interferences associated with an individual diagnostic sample can compromise any analyte. It is obvious that a process for a quality-control-sample-based approach of quality assurance is not sensitive to such errors. To address the potential causes and nature of such analytical interference in individual samples more systematically, we suggest the introduction of a new term called the irregular (individual) analytical error. Practically, this term can be applied in any analytical assay that is traceable to a reference measurement system. For an individual sample an irregular analytical error is defined as an inaccuracy (which is the deviation from a reference measurement procedure result) of a test result that is so high it cannot be explained by measurement uncertainty of the utilized routine assay operating within the accepted limitations of the associated process quality control measurements. The deviation can be defined as the linear combination of the process measurement uncertainty and the method bias for the reference measurement system. Such errors should be coined irregular analytical errors of the individual sample. The measurement result is compromised either by an irregular effect associated with the individual composition (matrix) of the sample or an individual single sample associated processing error in the analytical process. Currently, the availability of reference measurement procedures is still highly limited, but LC

  20. Stromal haze, myofibroblasts, and surface irregularity after PRK.

    Science.gov (United States)

    Netto, Marcelo V; Mohan, Rajiv R; Sinha, Sunilima; Sharma, Ajay; Dupps, William; Wilson, Steven E

    2006-05-01

    The aim of this study was to investigate the relationship between the level of stromal surface irregularity after photorefractive keratectomy (PRK) and myofibroblast generation along with the development of corneal haze. Variable levels of stromal surface irregularity were generated in rabbit corneas by positioning a fine mesh screen in the path of excimer laser during ablation for a variable percentage of the terminal pulses of the treatment for myopia that does not otherwise generate significant opacity. Ninety-six rabbits were divided into eight groups: [see table in text]. Slit lamp analysis and haze grading were performed in all groups. Rabbits were sacrificed at 4 hr or 4 weeks after surgery and histochemical analysis was performed on corneas for apoptosis (TUNEL assay), myofibroblast marker alpha-smooth muscle actin (SMA), and integrin alpha4 to delineate the epithelial basement membrane. Slit-lamp grading revealed severe haze formation in corneas in groups IV and VI, with significantly less haze in groups II, III, and VII and insignificant haze compared with the unwounded control in groups I and V. Analysis of SMA staining at 4 weeks after surgery, the approximate peak of haze formation in rabbits, revealed low myofibroblast formation in group I (1.2+/-0.2 cells/400x field) and group V (1.8+/-0.4), with significantly more in groups II (3.5+/-1.8), III (6.8+/-1.6), VII (7.9+/-3.8), IV (12.4+/-4.2) and VI (14.6+/-5.1). The screened groups were significantly different from each other (p PRK groups. The -9.0 diopter PRK group VI had significantly more myofibroblast generation than the -9.0 diopter PRK with PTK-smoothing group VII (p PRK and the level of stromal surface irregularity. PTK-smoothing with methylcellulose was an effective method to reduce stromal surface irregularity and decreased both haze and associated myofibroblast density. We hypothesize that stromal surface irregularity after PRK for high myopia results in defective basement membrane

  1. Teaching Teaching & Understanding Understanding

    DEFF Research Database (Denmark)

    2006-01-01

    "Teaching Teaching & Understanding Understanding" is a 19-minute award-winning short-film about teaching at university and higher-level educational institutions. It is based on the "Constructive Alignment" theory developed by Prof. John Biggs. The film delivers a foundation for understanding what...

  2. Women with minor menstrual irregularities have increased risk of preeclampsia and low birthweight in spontaneous pregnancies

    DEFF Research Database (Denmark)

    Bonnesen, Barbara; Oddgeirsdóttir, Hanna L; Naver, Klara Vinsand

    2016-01-01

    INTRODUCTION: Very few studies describe the obstetric and neonatal outcome of spontaneous pregnancies in women with irregular menstrual cycles. However, menstrual cycle irregularities are common and may be associated with increased risk, and women who develop pregnancy complications more frequent...

  3. Study of Track Irregularity Time Series Calibration and Variation Pattern at Unit Section

    Directory of Open Access Journals (Sweden)

    Chaolong Jia

    2014-01-01

    Full Text Available Focusing on problems existing in track irregularity time series data quality, this paper first presents abnormal data identification, data offset correction algorithm, local outlier data identification, and noise cancellation algorithms. And then proposes track irregularity time series decomposition and reconstruction through the wavelet decomposition and reconstruction approach. Finally, the patterns and features of track irregularity standard deviation data sequence in unit sections are studied, and the changing trend of track irregularity time series is discovered and described.

  4. Accuracy limits of the equivalent field method for irregular photon fields

    International Nuclear Information System (INIS)

    Sanz, Dario Esteban

    2002-01-01

    A mathematical approach is developed to evaluate the accuracy of the equivalent field method using basic clinical photon beam data. This paper presents an analytical calculation of dose errors arising when field equivalencies, calculated at a certain reference depth, are translated to other depths. The phantom scatter summation is expressed as a Riemann-Stieltjes integral and two categories of irregular fields are introduced: uniform and multiform. It is shown that multiform fields produce errors whose magnitudes are nearly twice those corresponding to uniform fields in extreme situations. For uniform field shapes, the maximum, local, relative dose errors, when the equivalencies are calculated at 10 cm depth on the central axis and translated to a depth of 30 cm, are 3.8% and 8.8% for 6 MV and cobalt-60 photon beams, respectively. In terms of maximum dose those errors are within 1-2%. This supports the conclusion that the equivalencies between rectangular fields, which are examples of uniform fields, are applicable to dose ratio functions irrespective of beam energy. However, the magnitude of such errors could be of importance when assessing the exit dose for in vivo monitoring. This work provides a better understanding of the influence of the irregular field shapes on the accuracy of the equivalent field method. (author)

  5. Similarity estimators for irregular and age uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2013-09-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  6. Similarity estimators for irregular and age-uncertain time series

    Science.gov (United States)

    Rehfeld, K.; Kurths, J.

    2014-01-01

    Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

  7. Ionospheric wave and irregularity measurements using passive radio astronomy techniques

    International Nuclear Information System (INIS)

    Erickson, W.C.; Mahoney, M.J.; Jacobson, A.R.; Knowles, S.H.

    1988-01-01

    The observation of midlatitude structures using passive radio astronomy techniques is discussed, with particular attention being given to the low-frequency radio telescope at the Clark Lake Radio Observatory. The present telescope operates in the 10-125-MHz frequency range. Observations of the ionosphere at separations of a few kilometers to a few hundreds of kilometers by the lines of sight to sources are possible, allowing the determination of the amplitude, wavelength, direction of propagation, and propagation speed of ionospheric waves. Data are considered on large-scale ionospheric gradients and the two-dimensional shapes and sizes of ionospheric irregularities. 10 references

  8. Analysis of an Irregular RC Multi-storeyed Building Subjected to Dynamic Loading

    Science.gov (United States)

    AkashRaut; Pachpor, Prabodh; Dautkhani, Sanket

    2018-03-01

    Many buildings in the present scenario have irregular configurations both in plan and elevation. This in future may subject to devastating earthquakes. So it is necessary to analyze the structure. The present paper is made to study three type of irregularity wiz vertical, mass and plan irregularity as per clause 7.1 of IS 1893 (part1)2002 code. The paper discusses the analysis of RC (Reinforced Concrete) Buildings with vertical irregularity. The study as a whole makes an effort to evaluate the effect of vertical irregularity on RC buildings for which comparison of three parameters namely shear force, bending moment and deflection are taken into account.

  9. Co-evolutionary organisational response development model (CORD): a case study of an Australian energy company climate change responses

    OpenAIRE

    Mishra, Kirti

    2016-01-01

    The thesis reports an investigation of the effects of the complex, evolving relationships between organisations and their environments. This examination is a case study of the responses of an Australian energy company to effects of climate change, and aims to enhance understanding of how organisational responses to climate change develop and evolve over time.    The impact of climate change on the contemporary organisational environment has multiple aspects – natural, ec...

  10. The Biosynthetic Origin of Irregular Monoterpenes in Lavandula

    Science.gov (United States)

    Demissie, Zerihun A.; Erland, Lauren A. E.; Rheault, Mark R.; Mahmoud, Soheil S.

    2013-01-01

    Lavender essential oils are constituted predominantly of regular monoterpenes, for example linalool, 1,8-cineole, and camphor. However, they also contain irregular monoterpenes including lavandulol and lavandulyl acetate. Although the majority of genes responsible for the production of regular monoterpenes in lavenders are now known, enzymes (including lavandulyl diphosphate synthase (LPPS)) catalyzing the biosynthesis of irregular monoterpenes in these plants have not been described. Here, we report the isolation and functional characterization of a novel cis-prenyl diphosphate synthase cDNA, termed Lavandula x intermedia lavandulyl diphosphate synthase (LiLPPS), through a homology-based cloning strategy. The LiLPPS ORF, encoding for a 305-amino acid long protein, was expressed in Escherichia coli, and the recombinant protein was purified by nickel-nitrilotriacetic acid affinity chromatography. The approximately 34.5-kDa bacterially produced protein specifically catalyzed the head-to-middle condensation of two dimethylallyl diphosphate units to LPP in vitro with apparent Km and kcat values of 208 ± 12 μm and 0.1 s−1, respectively. LiLPPS is a homodimeric enzyme with a sigmoidal saturation curve and Hill coefficient of 2.7, suggesting a positive co-operative interaction among its catalytic sites. LiLPPS could be used to modulate the production of lavandulol and its derivatives in plants through metabolic engineering. PMID:23306202

  11. Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

    Science.gov (United States)

    Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

    2008-09-01

    Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of archived MIPS observations of Phoebe reproduces Cassini results very accurately, thereby validating our method. For all targets, the geometric albedo is found to be low, probably below 10% and clearly below 15%. Irregular satellites are much darker than the large regular satellites. Their albedo is, however, quite similar to that of small bodies in the outer Solar System (such as cometary nuclei, Jupiter Trojans, or TNOs). This is consistent with color measurements as well as dynamical considerations which suggest a common origin of the said populations. There appear to be significant object-to-object albedo differences. Similar albedos found for some members of dynamical clusters support the idea that they may have originated in the breakup of a parent body. For three satellites, thermal data at two wavelengths are available, enabling us to constrain their thermal properties. Sub-solar temperatures are similar to that found from Cassini's Phoebe fly-by. This suggests a rather low thermal inertia, as expected for regolith-covered objects. This work is based on observations made with the Spitzer Space Telescope, which is operated by JPL under a contract with NASA. Support for this work was provided by NASA.

  12. Non-storm irregular variation of the Dst index

    Directory of Open Access Journals (Sweden)

    S. Nakano

    2012-01-01

    Full Text Available The Dst index has a long-term variation that is not associated with magnetic storms. We estimated the long-term non-storm component of the Dst variation by removing the short-term variation related to magnetic storms. The results indicate that the variation of the non-storm component includes not only a seasonal variation but also an irregular variation. The irregular long-term variation is likely to be due to an anti-correlation with the long-term variation of solar-wind activity. In particular, a clear anti-correlation is observed between the non-storm component of Dst and the long-term variation of the solar-wind dynamic pressure. This means that in the long term, the Dst index tends to increase when the solar-wind dynamic pressure decreases. We interpret this anti-correlation as an indication that the long-term non-storm variation of Dst is influenced by the tail current variation. The long-term variation of the solar-wind dynamic pressure controls the plasma sheet thermal pressure, and the change of the plasma sheet thermal pressure would cause the non-storm tail current variation, resulting in the non-storm variation of Dst.

  13. Irregular working hours and fatigue of cabin crew.

    Science.gov (United States)

    Castro, Marta; Carvalhais, José; Teles, Júlia

    2015-01-01

    Beyond workload and specific environmental factors, flight attendants can be exposed to irregular working hours, conflicting with their circadian rhythms and having a negative impact in sleep, fatigue, health, social and family life, and performance which is critical to both safety and security in flight operations. This study focuses on the irregular schedules of cabin crew as a trigger of fatigue symptoms in a wet lease Portuguese airline. The aim was to analyze: what are the requirements of the cabin crew work; whether the schedules being observed and effective resting timeouts are triggering factors of fatigue; and the existence of fatigue symptoms in the cabin crew. A questionnaire has been adapted and applied to a sample of 73 cabin crew-members (representing 61.9% of the population), 39 females and 34 males, with an average age of 27.68 ± 4.27 years. Our data indicate the presence of fatigue and corresponding health symptoms among the airline cabin crew, despite of the sample favorable characteristics. Senior workers and women are more affected. Countermeasures are required. Recommendations can be made regarding the fatigue risk management, including work organization, education and awareness training programmes and specific countermeasures.

  14. Model tracking dual stochastic controller design under irregular internal noises

    International Nuclear Information System (INIS)

    Lee, Jong Bok; Heo, Hoon; Cho, Yun Hyun; Ji, Tae Young

    2006-01-01

    Although many methods about the control of irregular external noise have been introduced and implemented, it is still necessary to design a controller that will be more effective and efficient methods to exclude for various noises. Accumulation of errors due to model tracking, internal noises (thermal noise, shot noise and l/f noise) that come from elements such as resistor, diode and transistor etc. in the circuit system and numerical errors due to digital process often destabilize the system and reduce the system performance. New stochastic controller is adopted to remove those noises using conventional controller simultaneously. Design method of a model tracking dual controller is proposed to improve the stability of system while removing external and internal noises. In the study, design process of the model tracking dual stochastic controller is introduced that improves system performance and guarantees robustness under irregular internal noises which can be created internally. The model tracking dual stochastic controller utilizing F-P-K stochastic control technique developed earlier is implemented to reveal its performance via simulation

  15. Using Radio Irregularity for Increasing Residential Energy Awareness

    Directory of Open Access Journals (Sweden)

    A. Miljković

    2012-06-01

    Full Text Available Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper, the method of using radio irregularity as an efficient human presence detection sensor in smart homes is presented. The method is mainly based on monitoring variations of the received signal strength indicator (RSSI within the messages used for the communication between wireless smart power outlets. The radio signals used for the inter-outlets communication can be absorbed, diffracted or reflected by objects in their propagation paths. When a human enters the existing radio communication field, the variation of the signal strength at the receiver is even more expressed. Based on the detected changes and compared to the initial thresholds set during the initialization phase, the system detects human presence. The proposed solution increases user awareness and automates the power control in households, with the primary goal to contribute in residential energy savings. Compared to conventional sensor networks, this approach preserves the sensorial intelligence, simplicity and low installation costs, without the need for additional sensors integration.

  16. Colombia: la guerra irregular en el fin de siglo

    Directory of Open Access Journals (Sweden)

    Alfredo RANGEL SUÁREZ

    2009-11-01

    Full Text Available RESUMEN: El artículo analiza las transformaciones de la guerra irregular de las guerrillas colombianas en las últimas décadas. Para ello, se estudian los cambios que han afectado a distintos factores, como los objetivos estratégicos, los medios financieros, militares, las relaciones que mantienen con los partidos políticos tradicionales en el nivel local, sus parámetros ideológicos, el origen social de sus miembros. Con esta perspectiva, se analiza el cálculo político/temporal que la guerrilla hace en la actual coyuntura y sus consecuencias para el proceso de paz.ABSTRACT: This article examines the transformations of the irregular war of the colombian guerrillas, studying the changes of several factors such as the strategic goals, the financial and army resources, the relationship among the political parties in the local level, the evolution of their ideological parameters and of the social origin of their members. With this perspectiva, the author analyses temporal and political calculation that the guerrilla makes at this point, and its consequences for the peace process.

  17. Nonadiabatic two-electron transfer mediated by an irregular bridge

    International Nuclear Information System (INIS)

    Petrov, E.G.; Shevchenko, Ye.V.; May, V.

    2004-01-01

    Nonadiabatic two-electron transfer (TET) mediated by a linear molecular bridge is studied theoretically. Special attention is put on the case of a irregular distribution of bridge site energies as well as on the inter-site Coulomb interaction. Based on the unified description of electron transfer reactions [J. Chem. Phys. 115 (2001) 7107] a closed set of kinetic equations describing the TET process is derived. A reduction of this set to a single exponential donor-acceptor (D-A) TET is performed together with a derivation of an overall D-A TET rate. The latter contains a contribution of the stepwise as well as of the concerted route of D-A TET. The stepwise contribution is determined by two single-electron steps each of them associated with a sequential and a superexchange pathway. A two-electron unistep superexchange transition between the D and A forms the concerted contribution to the overall rate. Both contributions are analyzed in their dependency on the bridge length. The irregular distribution of the bridge site energies as well as the influence of the Coulomb interaction facilitates the D-A TET via a modification of the stepwise and the concerted part of the overall rate. At low temperatures and for short bridges with a single or two units the concerted contribution exceeds the stepwise contribution. If the bridge contains more than two units, the stepwise contribution dominates the overall rate

  18. Designing Next Generation Massively Multithreaded Architectures for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tumeo, Antonino; Secchi, Simone; Villa, Oreste

    2012-08-31

    Irregular applications, such as data mining or graph-based computations, show unpredictable memory/network access patterns and control structures. Massively multi-threaded architectures with large node count, like the Cray XMT, have been shown to address their requirements better than commodity clusters. In this paper we present the approaches that we are currently pursuing to design future generations of these architectures. First, we introduce the Cray XMT and compare it to other multithreaded architectures. We then propose an evolution of the architecture, integrating multiple cores per node and next generation network interconnect. We advocate the use of hardware support for remote memory reference aggregation to optimize network utilization. For this evaluation we developed a highly parallel, custom simulation infrastructure for multi-threaded systems. Our simulator executes unmodified XMT binaries with very large datasets, capturing effects due to contention and hot-spotting, while predicting execution times with greater than 90% accuracy. We also discuss the FPGA prototyping approach that we are employing to study efficient support for irregular applications in next generation manycore processors.

  19. Experimental and theoretical study of the onset of the growth of an irregular metal electrodeposit

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Graciela [Laboratoire de Physique de la Matiere Condensee, CNRS-Ecole Polytechnique, F91128 Palaiseau Cedex (France); Laboratorio de Sistemas Complejos, Departamento de Computacion, Facultad de Ciencias, Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina); Rosso, Michel; Chazalviel, Jean-Noel [Laboratoire de Physique de la Matiere Condensee, CNRS-Ecole Polytechnique, F91128 Palaiseau Cedex (France); Chassaing, Elisabeth [IRDEP, EDF R and D, 6 Quai Watier, 78401 Chatou (France)

    2007-11-20

    Electrodeposition of a metal can produce aggregates with very irregular morphologies, in particular dendrites. In order to better understand these phenomena, we studied the preliminary stage of copper growth from copper sulfate by in situ optical experiments and impedance spectroscopy. Experiments were performed in a thin layer cell put in a vertical position, with cathode on top. Using a vertical cell instead of a horizontal one tends to stabilize the electrochemical system. The concentration measured by optical absorption is in agreement with theoretical prediction at the onset of polarization. Close to the limiting current density, oscillations were observed in the cell voltage. Impedance spectra could be fitted either using a simple equivalent circuit at low current density, or more complex calculations at high current density. (author)

  20. Major depression in China-to-US immigrants and US-born Chinese Americans: testing a hypothesis from culture-gene co-evolutionary theory of mental disorders.

    Science.gov (United States)

    Tan, Tony Xing

    2014-01-01

    In this study, the culture-gene co-evolutionary theory of mental disorders was used to test the hypothesis that major depression was less prevalent in China-to-US immigrants who migrated to the US as adults than in US-born adult Chinese Americans. Data from the Collaborative Psychiatric Epidemiology Surveys (CPES) were extracted for secondary data analyses on the rates of major depression disorder (MDD) and major depressive episode (MDE) in the two groups. Findings showed that for life time MDD, the rates for China-to-US immigrant and US-born Chinese were 5.3% and 7.9% for men and 8.5% and 33.1% for women. For 12-month MDD, the corresponding rates were 2.2% and 3.4% for men, and 4.7% and 12.6% for women. For life time MDE, the corresponding rates were 6.8% and 8.8% for men; for women the rates were 8.5% and 33.1%. For 12-month MDE, the rates were 2.2% and 4.4% for men; the rates were 4.7% and 12.6% for women. Controlling for age, education level, income, BMI, marital status, and income-to-needs ratio, China-to-US immigrant women remained less likely to have life time major depression than US-born Chinese American women. While the study has the strength of utilizing nationally representative datasets, the approach is limited as the data sources lack the capacity to investigate how the strength of connection with the collectivist culture might be related to major depression in the immigrant group. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Compensation for unfavorable characteristics of irregular individual shift rotas.

    Science.gov (United States)

    Knauth, Peter; Jung, Detlev; Bopp, Winfried; Gauderer, Patric C; Gissel, Andreas

    2006-01-01

    Some employees of TV companies, such as those who produce remote TV programs, have to cope with very irregular rotas and many short-term schedule deviations. Many of these employees complain about the negative effects of such on their wellbeing and private life. Therefore, a working group of employers, council representatives, and researchers developed a so-called bonus system. Based on the criteria of the BESIAK system, the following list of criteria for the ergonomic assessment of irregular shift systems was developed: proportion of night hours worked between 22 : 00 and 01 : 00 h and between 06 : 00 and 07 : 00 h, proportion of night hours worked between 01 : 00 and 06 : 00 h, number of successive night shifts, number of successive working days, number of shifts longer than 9 h, proportion of phase advances, off hours on weekends, work hours between 17 : 00 and 23 : 00 h from Monday to Friday, number of working days with leisure time at remote places, and sudden deviations from the planned shift rota. Each individual rota was evaluated in retrospect. If pre-defined thresholds of criteria were surpassed, bonus points were added to the worker's account. In general, more bonus points add up to more free time. Only in particular cases was monetary compensation possible for some criteria. The bonus point system, which was implemented in the year 2002 for about 850 employees of the TV company, has the advantages of more transparency concerning the unfavorable characteristics of working-time arrangements, incentive for superiors to design "good" rosters that avoid the bonus point thresholds (to reduce costs), positive short-term effects on the employee social life, and expected positive long-term effects on the employee health. In general, the most promising approach to cope with the problems of shift workers in irregular and flexible shift systems seems to be to increase their influence on the arrangement of working times. If this is not possible, bonus point systems

  2. Strain-rate effect on initial crush stress of irregular honeycomb under dynamic loading and its deformation mechanism

    Science.gov (United States)

    Wang, Peng; Zheng, Zhijun; Liao, Shenfei; Yu, Jilin

    2018-02-01

    The seemingly contradictory understandings of the initial crush stress of cellular materials under dynamic loadings exist in the literature, and a comprehensive analysis of this issue is carried out with using direct information of local stress and strain. Local stress/strain calculation methods are applied to determine the initial crush stresses and the strain rates at initial crush from a cell-based finite element model of irregular honeycomb under dynamic loadings. The initial crush stress under constant-velocity compression is identical to the quasi-static one, but less than the one under direct impact, i.e. the initial crush stresses under different dynamic loadings could be very different even though there is no strain-rate effect of matrix material. A power-law relation between the initial crush stress and the strain rate is explored to describe the strain-rate effect on the initial crush stress of irregular honeycomb when the local strain rate exceeds a critical value, below which there is no strain-rate effect of irregular honeycomb. Deformation mechanisms of the initial crush behavior under dynamic loadings are also explored. The deformation modes of the initial crush region in the front of plastic compaction wave are different under different dynamic loadings.

  3. Toxicological effects of irregularly shaped and spherical microplastics in a marine teleost, the sheepshead minnow (Cyprinodon variegatus).

    Science.gov (United States)

    Choi, Jin Soo; Jung, Youn-Joo; Hong, Nam-Hui; Hong, Sang Hee; Park, June-Woo

    2018-04-01

    The increasing global contamination of plastics in marine environments is raising public concerns about the potential hazards of microplastics to environmental and human health. Microplastics formed by the breakdown of larger plastics are typically irregular in shape. The objective of this study was to compare the effects of spherical or irregular shapes of microplastics on changes in organ distribution, swimming behaviors, gene expression, and enzyme activities in sheepshead minnow (Cyprinodon variegatus). Both types of microplastics accumulated in the digestive system, causing intestinal distention. However, when compared to spherical microplastics, irregular microplastics decreased swimming behavior (i.e., total distance travelled and maximum velocity) of sheepshead minnow. Both microplastics generated cellular reactive oxygen species (ROS), while ROS-related molecular changes (i.e., transcriptional and enzymatic characteristics) differed. This study provides toxicological insights into the impacts of environmentally relevant (fragmented) microplastics on fish and improves our understanding of the environmental effects of microplastics in the ecosystem. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Airway surface irregularities promote particle diffusion in the human lung

    International Nuclear Information System (INIS)

    Martonen, T.; North Carolina Univ., Chapel Hill, NC; Zhang, Z.; Yang, Y.; Bottei, G.

    1995-01-01

    Current NCRP and ICRP particle deposition models employed in risk assessment analyses treat the airways of the human lung as smooth-walled tubes. However, the upper airways of the tracheobronchial (TB) tree are line with cartilaginous rings. Recent supercomputer simulations of in vivo conditions (cited herein), where cartilaginous ring morphologies were based upon fibre-optic bronchoscope examinations, have clearly demonstrated their profound effects upon fluid dynamics. A physiologically based analytical model of fluid dynamics is presented, focusing upon applications to particle diffusion within the TB tree. The new model is the first to describe particle motion while simultaneously simulating effects of wall irregularities, entrance conditions and tube curvatures. This study may explain the enhanced deposition by particle diffusion detected in replica case experiments and have salient implications for the clinically observed preferential distributions of bronchogenic carcinomas associated with inhaled radionuclides. (author)

  5. Massive stars in the Sagittarius Dwarf Irregular Galaxy

    Science.gov (United States)

    Garcia, Miriam

    2018-02-01

    Low metallicity massive stars hold the key to interpret numerous processes in the past Universe including re-ionization, starburst galaxies, high-redshift supernovae, and γ-ray bursts. The Sagittarius Dwarf Irregular Galaxy [SagDIG, 12+log(O/H) = 7.37] represents an important landmark in the quest for analogues accessible with 10-m class telescopes. This Letter presents low-resolution spectroscopy executed with the Gran Telescopio Canarias that confirms that SagDIG hosts massive stars. The observations unveiled three OBA-type stars and one red supergiant candidate. Pending confirmation from high-resolution follow-up studies, these could be the most metal-poor massive stars of the Local Group.

  6. Evaluation of Surface Slope Irregularity in Linear Parabolic Solar Collectors

    Directory of Open Access Journals (Sweden)

    F. Francini

    2012-01-01

    Full Text Available The paper describes a methodology, very simple in its application, for measuring surface irregularities of linear parabolic collectors. This technique was principally developed to be applied in cases where it is difficult to use cumbersome instruments and to facilitate logistic management. The instruments to be employed are a digital camera and a grating. If the reflector surface is defective, the image of the grating, reflected on the solar collector, appears distorted. Analyzing the reflected image, we can obtain the local slope of the defective surface. These profilometric tests are useful to identify and monitor the mirror portions under mechanical stress and to estimate the losses caused by the light rays deflected outside the absorber.

  7. Constructing a logical, regular axis topology from an irregular topology

    Science.gov (United States)

    Faraj, Daniel A.

    2014-07-01

    Constructing a logical regular topology from an irregular topology including, for each axial dimension and recursively, for each compute node in a subcommunicator until returning to a first node: adding to a logical line of the axial dimension a neighbor specified in a nearest neighbor list; calling the added compute node; determining, by the called node, whether any neighbor in the node's nearest neighbor list is available to add to the logical line; if a neighbor in the called compute node's nearest neighbor list is available to add to the logical line, adding, by the called compute node to the logical line, any neighbor in the called compute node's nearest neighbor list for the axial dimension not already added to the logical line; and, if no neighbor in the called compute node's nearest neighbor list is available to add to the logical line, returning to the calling compute node.

  8. Global scale ionospheric irregularities associated with thunderstorm activity

    International Nuclear Information System (INIS)

    Pulinets, Sergey A.; Depuev, Victor H.

    2003-01-01

    The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstorm electric fields onto the Earth's ionosphere. (author)

  9. Global scale ionospheric irregularities associated with thunderstorm activity

    CERN Document Server

    Pulinets, S A

    2002-01-01

    The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstor...

  10. Asymmetry and irregularity border as discrimination factor between melanocytic lesions

    Science.gov (United States)

    Sbrissa, David; Pratavieira, Sebastião.; Salvio, Ana Gabriela; Kurachi, Cristina; Bagnato, Vanderlei Salvadori; Costa, Luciano Da Fontoura; Travieso, Gonzalo

    2015-06-01

    Image processing tools have been widely used in systems supporting medical diagnosis. The use of mobile devices for the diagnosis of melanoma can assist doctors and improve their diagnosis of a melanocytic lesion. This study proposes a method of image analysis for melanoma discrimination from other types of melanocytic lesions, such as regular and atypical nevi. The process is based on extracting features related with asymmetry and border irregularity. It were collected 104 images, from medical database of two years. The images were obtained with standard digital cameras without lighting and scale control. Metrics relating to the characteristics of shape, asymmetry and curvature of the contour were extracted from segmented images. Linear Discriminant Analysis was performed for dimensionality reduction and data visualization. Segmentation results showed good efficiency in the process, with approximately 88:5% accuracy. Validation results presents sensibility and specificity 85% and 70% for melanoma detection, respectively.

  11. Manufacturing of Cast Metal Foams with Irregular Cell Structure

    Directory of Open Access Journals (Sweden)

    Kroupová I.

    2015-06-01

    Full Text Available Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive industry, building industry, medicine, etc.. These metallic materials have specific properties, such as large rigidity at low density, high thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting technology (infiltration method, which ensures rapid and economically feasible method for production of shaped components. In the experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous alloys by use of various types of filler material (precursors.

  12. Method for hot pressing irregularly shaped refractory articles

    Science.gov (United States)

    Steinkamp, William E.; Ballard, Ambrose H.

    1982-01-01

    The present invention is directed to a method for hot pressing irregularly haped refractory articles with these articles of varying thickness being provided with high uniform density and dimensional accuracy. Two partially pressed compacts of the refractory material are placed in a die cavity between displaceable die punches having compact-contacting surfaces of the desired article configuration. A floating, rotatable block is disposed between the compacts. The displacement of the die punches towards one another causes the block to rotate about an axis normal to the direction of movement of the die punches to uniformly distribute the pressure loading upon the compacts for maintaining substantially equal volume displacement of the powder material during the hot pressing operation.

  13. Irregular Migration - between legal status and social practices

    DEFF Research Database (Denmark)

    Lund Thomsen, Trine

    2012-01-01

    Arnfinn H. and Rogstad, Jon 2.Book reviews by null 3.INVISIBLE IMMIGRANTS, VISIBLE EXPATS? Americans in Finnish discourses on immigration and internationalization by Leinonen, Johanna 4.Migrants in the Scandinavian Welfare State by Brochmann, Grete and Hagelund, Anniken 5.TOWARD AN IDENTITY STRESS....... Language and religious affiliations of an immigrant adolescent in Norway by Haque, Shahzaman View Top 20 Most Downloaded Articles Previous Article Next Article Go to table of contents Download full text pdf (PDF, 425 KB) Irregular Migration – Between Legal Status and Social Practices Narratives of Polish...... connected to the specific area of activity and to the accumulated capital of the individual. The aim is to identify how opportunity structures affect the migration process and how migrants react to them depending on the available capital and biographical knowledge and experiences. The horizon of experience...

  14. New Computational Approach to Electron Transport in Irregular Graphene Nanostructures

    Science.gov (United States)

    Mason, Douglas; Heller, Eric; Prendergast, David; Neaton, Jeffrey

    2009-03-01

    For novel graphene devices of nanoscale-to-macroscopic scale, many aspects of their transport properties are not easily understood due to difficulties in fabricating devices with regular edges. Here we develop a framework to efficiently calculate and potentially screen electronic transport properties of arbitrary nanoscale graphene device structures. A generalization of the established recursive Green's function method is presented, providing access to arbitrary device and lead geometries with substantial computer-time savings. Using single-orbital nearest-neighbor tight-binding models and the Green's function-Landauer scattering formalism, we will explore the transmission function of irregular two-dimensional graphene-based nanostructures with arbitrary lead orientation. Prepared by LBNL under contract DE-AC02-05CH11231 and supported by the U.S. Dept. of Energy Computer Science Graduate Fellowship under grant DE-FG02-97ER25308.

  15. Kriging for interpolation of sparse and irregularly distributed geologic data

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, K.

    1986-12-31

    For many geologic problems, subsurface observations are available only from a small number of irregularly distributed locations, for example from a handful of drill holes in the region of interest. These observations will be interpolated one way or another, for example by hand-drawn stratigraphic cross-sections, by trend-fitting techniques, or by simple averaging which ignores spatial correlation. In this paper we consider an interpolation technique for such situations which provides, in addition to point estimates, the error estimates which are lacking from other ad hoc methods. The proposed estimator is like a kriging estimator in form, but because direct estimation of the spatial covariance function is not possible the parameters of the estimator are selected by cross-validation. Its use in estimating subsurface stratigraphy at a candidate site for geologic waste repository provides an example.

  16. Towards intrinsic magnetism of graphene sheets with irregular zigzag edges.

    Science.gov (United States)

    Chen, Lianlian; Guo, Liwei; Li, Zhilin; Zhang, Han; Lin, Jingjing; Huang, Jiao; Jin, Shifeng; Chen, Xiaolong

    2013-01-01

    The magnetism of graphene has remained divergent and controversial due to absence of reliable experimental results. Here we show the intrinsic magnetism of graphene edge states revealed based on unidirectional aligned graphene sheets derived from completely carbonized SiC crystals. It is found that ferromagnetism, antiferromagnetism and diamagnetism along with a probable superconductivity exist in the graphene with irregular zigzag edges. A phase diagram is constructed to show the evolution of the magnetism. The ferromagnetic ordering curie-temperature of the fundamental magnetic order unit (FMOU) is 820 ± 80 K. The antiferromagnetic ordering Neel temperature of the FMOUs belonging to different sublattices is about 54 ± 2 K. The diamagnetism is similar to that of graphite and can be well described by the Kotosonov's equation. Our experimental results provide new evidences to clarify the controversial experimental phenomena observed in graphene and contribute to a deeper insight into the nature of magnetism in graphene based system.

  17. Combined radar observations of equatorial electrojet irregularities at Jicamarca

    Directory of Open Access Journals (Sweden)

    D. L. Hysell

    2007-03-01

    Full Text Available Daytime equatorial electrojet plasma irregularities were investigated using five distinct radar diagnostics at Jicamarca including range-time-intensity (RTI mapping, Faraday rotation, radar imaging, oblique scattering, and multiple-frequency scattering using the new AMISR prototype UHF radar. Data suggest the existence of plasma density striations separated by 3–5 km and propagating slowly downward. The striations may be caused by neutral atmospheric turbulence, and a possible scenario for their formation is discussed. The Doppler shifts of type 1 echoes observed at VHF and UHF frequencies are compared and interpreted in light of a model of Farley Buneman waves based on kinetic ions and fluid electrons with thermal effects included. Finally, the up-down and east-west asymmetries evident in the radar observations are described and quantified.

  18. Comparison of different dose calculation methods for irregular photon fields

    International Nuclear Information System (INIS)

    Zakaria, G.A.; Schuette, W.

    2000-01-01

    In this work, 4 calculation methods (Wrede method, Clarskon method of sector integration, beam-zone method of Quast and pencil-beam method of Ahnesjoe) are introduced to calculate point doses in different irregular photon fields. The calculations cover a typical mantle field, an inverted Y-field and different blocked fields for 4 and 10 MV photon energies. The results are compared to those of measurements in a water phantom. The Clarkson and the pencil-beam method have been proved to be the methods of equal standard in relation to accuracy. Both of these methods are being distinguished by minimum deviations and applied in our clinical routine work. The Wrede and beam-zone methods deliver useful results to central beam and yet provide larger deviations in calculating points beyond the central axis. (orig.) [de

  19. Tamoxifen treatment of bleeding irregularities associated with Norplant use.

    Science.gov (United States)

    Abdel-Aleem, Hany; Shaaban, Omar M; Amin, Ahmed F; Abdel-Aleem, Aly M

    2005-12-01

    To evaluate the possible role of tamoxifen (selective estrogen receptor modulators, SERM) in treating bleeding irregularities associated with Norplant contraceptive use. Randomized clinical trial including 100 Norplant users complaining of vaginal bleeding irregularities. The trial was conducted in the Family Planning Clinic of Assiut University Hospital. Women were assigned at random to receive tamoxifen tablets (10 mg) twice daily for 10 days or similar placebo. Women were followed-up for 3 months. The end points were percentage of women who stopped bleeding during treatment, bleeding/spotting days during the period of follow-up, effect of treatment on their lifestyle, and side effects and discontinuation of contraception. There was good compliance with treatment. At the end of treatment, a significantly higher percentage of tamoxifen users stopped bleeding in comparison to the control group (88% vs. 68%, respectively; p=.016). Women who used tamoxifen had significantly less bleeding and/or spotting days than women who used placebo, during the first and second months. During the third month, there were no significant differences between the two groups. Women who used tamoxifen reported improvement in performing household activities, religious duties and in sexual life, during the first 2 months. In the third month, there were no differences between the two groups. There were no significant differences between tamoxifen and placebo groups in reporting side effects. In the group who used tamoxifen, two women discontinued Norplant use because of bleeding vs. nine women in the placebo group. Tamoxifen use at a dose of 10 mg twice daily orally, for 10 days, has a beneficial effect on vaginal bleeding associated with Norplant use. In addition, the bleeding pattern was better in women who used tamoxifen for the following 2 months after treatment. However, these results have to be confirmed in a larger trial before advocating this line of treatment.

  20. Volume determination of irregularly-shaped quasi-spherical nanoparticles.

    Science.gov (United States)

    Attota, Ravi Kiran; Liu, Eileen Cherry

    2016-11-01

    Nanoparticles (NPs) are widely used in diverse application areas, such as medicine, engineering, and cosmetics. The size (or volume) of NPs is one of the most important parameters for their successful application. It is relatively straightforward to determine the volume of regular NPs such as spheres and cubes from a one-dimensional or two-dimensional measurement. However, due to the three-dimensional nature of NPs, it is challenging to determine the proper physical size of many types of regularly and irregularly-shaped quasi-spherical NPs at high-throughput using a single tool. Here, we present a relatively simple method that determines a better volume estimate of NPs by combining measurements from their top-down projection areas and peak heights using two tools. The proposed method is significantly faster and more economical than the electron tomography method. We demonstrate the improved accuracy of the combined method over scanning electron microscopy (SEM) or atomic force microscopy (AFM) alone by using modeling, simulations, and measurements. This study also exposes the existence of inherent measurement biases for both SEM and AFM, which usually produce larger measured diameters with SEM than with AFM. However, in some cases SEM measured diameters appear to have less error compared to AFM measured diameters, especially for widely used IS-NPs such as of gold, and silver. The method provides a much needed, proper high-throughput volumetric measurement method useful for many applications. Graphical Abstract The combined method for volume determination of irregularly-shaped quasi-spherical nanoparticles.

  1. Reproducibility of irregular radiation fields for malignant lymphoma

    International Nuclear Information System (INIS)

    Mock, U.; Dieckmann, K.; Poetter, R.; Molitor, A.M.; Haverkamp, U.

    1998-01-01

    Purpose: Radiation treatment for malignant lymphoma requires large field irradiation with irregular blocks according to the individual anatomy and tumor configuration. For determination of safety margins (PTV) we quantitatively analysed the accuracy of field and block placement with regard to different anatomical regions. Patients and Methods: Forty patients with malignant lymphoma were irradiated using the classical supra-/infradiaphragmatic field arrangements. Treatment was performed with 10-MeV photons and irregularly shaped, large opposing fields. We evaluated the accuracy of field and block placements during the treatment courses by comparing the regularly performed verification - with the simulation films. Deviations were determined with respect to the field edges and the central axis, along the x- and z-axis. Results: With regard to the field edges, mean deviations of 2.0 mm and 3.4 mm were found along the x- and z-axis. The corresponding standard deviations were 3.4 mm and 5.5 mm, respectively. With regard to the shielding blocks, mean displacement along the x- and z-axis was 2.2 mm and 3.8 mm. In addition, overall standard deviations of 5.7 mm (x-axis) and 7.1 mm (z-axis) were determined. During the course of time an improved accuracy of block placement was notable. Conclusion: Systematic analysis of port films gives information for a better defining safety margins in external radiotherapy. Evaluation of verification films on a regular basis improves set-up accuracy by reducing displacements. (orig.) [de

  2. Measurements of electron density irregularities in the ionosphere of Jupiter by Pioneer 10

    International Nuclear Information System (INIS)

    Woo, R.; Yang, F.

    1976-01-01

    In this paper we demonstrate that when the frequency spectrum of the log amplitude fluctuations is used, the radio occultation experiment is a powerful tool for detecting, identifying, and studying ionospheric irregularities. Analysis of the Pioneer 10 radio occultation measurements reveals that the Jovian ionosphere possesses electron density irregularities which are very similar to those found in the earth's ionosphere. This is the first time such irregularities have been found in a planetary ionosphere other than that of earth. The Pioneer 10 results indicate that the spatial wave number spectrum of the electron density irregularities is close to the Kolmogorov spectrum and that the outer scale size is greater than the Fresnel size (6.15 km). This type of spectrum suggests that the irregularities are probably produced by the turbulent dissipation of irregularities larger than the outer scale size

  3. Towards generalizing co-evolutionary dynamics of socio-hydrology: Theoretical frameworks of cultural evolution and robustness-fragility tradeoff

    Science.gov (United States)

    Oh, W. S.; Yu, D. J.; Davis, T.; Hillis, V.; Waring, T. M.

    2017-12-01

    One ongoing challenge to socio-hydrology is the problem of generalization: to what extent do common human-water co-evolutions exist across distinct cases and what are underlying mechanisms of these co-evolutions. This problem stems in part from a lack of unifying theories in socio-hydrology, which hinders the explanation and generalization of results between cases in different regions. Theories help an analyst to make assumptions that are necessary to diagnose a specific phenomenon, to explain the general mechanisms of causation, and, thus, to predict future outcomes. To help address the issue, this study introduces two theories that are increasingly used in the fields of sustainability science and social-ecological systems research: robustness-fragility tradeoff (RFTO) and cultural multi-level selection (CMLS). We apply each of these theories to two distinct cases (water management issues in southwest Bangladesh and the Kissimmee River Basin, Florida) and interpret the phenomena of the levee and adaptation effects. CMLS and RFTO focus on complementary aspects of socio-hydrological phenomena. The theory of RFTO, which is mostly about inherent tradeoffs associated with infrastructure improvements, explains how efforts to increase system robustness can generate hidden endogenous risks. CMLS theory, rooted in the broader theory of cultural evolution, concerns how human cultural dynamics can act as an endogenous driver of system change across multiple levels of social organizations. Using the applied examples, we demonstrate that these two theories can provide an effective way to study social-hydrological systems and to overcome the generalization problem. Our work shows that multiple theories can be synthesized to give a richer understanding of diverse socio-hydrological patterns.

  4. Experimental investigation of coolability behaviour of irregularly shaped particulate debris bed

    International Nuclear Information System (INIS)

    Kulkarni, P.P.; Rashid, M.; Kulenovic, R.; Nayak, A.K.

    2010-01-01

    In case of a severe nuclear reactor accident, the core can melt and form a particulate debris bed in the lower plenum of the reactor pressure vessel (RPV). Due to the decay heat, the particle bed, if not cooled properly, can cause failure of the RPV. In order to avoid further propagation of the accident, complete coolability of the debris bed is necessary. For that, understanding of various phenomena taking place during the quenching is important. In the frame of the reactor safety research, fundamental experiments on the coolability of debris beds are carried out at IKE with the test facility 'DEBRIS'. In the present paper, the boiling and dry-out experimental results on a particle bed with irregularly shaped particles mixed with stainless steel balls have been reported. The pressure drops and dry-out heat fluxes of the irregular-particle bed are very similar to those for the single-sized 3 mm spheres bed, despite the fact that the irregular-particle bed is composed of particles with equivalent diameters ranging from 2 to 10 mm. Under top-flooding conditions, the pressure gradients are all smaller than the hydrostatic pressure gradient of water, indicating an important role of the counter-current interfacial drag force. For bottom-flooding with a liquid inflow velocity higher than about 2.7 mm/s, the pressure gradient generally increases consistently with the vapour velocity and the fluid-particle drag becomes important. The system pressures (1 and 3 bar) have negligible effects on qualitative behaviour of the pressure gradients. The coolability of debris beds is mainly limited by the counter-current flooding limit (CCFL) even under bottom-flooding conditions with low flow rates. The system pressure and the flow rate are found to have a distinct effect on the dry-out heat flux. Different classical models have been used to predict the pressure drop characteristics and the dry-out heat flux (DHF). Comparisons are made among the models and experimental results for

  5. Crime among irregular immigrants and the influence of internal border control

    OpenAIRE

    Leerkes, Arjen; Engbersen, Godfried; Leun, Joanne

    2012-01-01

    textabstractBoth the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular immigrants from the formal labour market and public provisions. At the same time the registered crime among irregular migrants rose. The 'marginalisation thesis' asserts that a larger number of migrants hav...

  6. Effects of magnetic storm phases on F layer irregularities below the auroral oval

    International Nuclear Information System (INIS)

    Aarons, J.; Gurgiolo, C.; Rodger, A.S.

    1988-01-01

    Observations of F-layer irregularity development and intensity were obtained between September and October 1981, primarily over subauroral latitudes in the area of the plasmapause. The results reveal the descent of the auroral irregularity region to include subauroral latitudes in the general area of the plasmapause during the main phases of a series of magnetic storms. Irregularities were found primarily at lower latitudes during the subauroral or plasmapause storm. A model for the subauroral irregularities in recovery phases of magnetic storms is proposed in which energy stored in the ring current is slowly released. 27 references

  7. Dependence on zenith angle of the strength of 3-meter equatorial electrojet irregularities

    International Nuclear Information System (INIS)

    Ierkic, H.M.; Fejer, B.G.; Farley, D.T.

    1980-01-01

    Radar measurements in Peru were used to deduce the zenith angle dependence of the scattering cross section of plasma irregularities generated by instabilities in the equatorial electrojet. The irregularities probed by the 50 MHz Jicamarca radar had a wavelength of 3m. The cross section for the type 2 irregularities was isotopic in the plane perpendicular to the magnetic field, while the cross section for the stronger type 1 irregularities varied with zenith angle at a rate of approximately 0.3 dB/degree; the horizontally traveling waves were more than 100 times stronger than those traveling vertically

  8. Spatial irregularities in Jupiter's upper ionosphere observed by Voyager radio occultations

    Science.gov (United States)

    Hinson, D. P.; Tyler, G. L.

    1982-01-01

    Radio scintillations (at 3.6 and 13 cm) produced by scattering from ionospheric irregularities during the Voyager occultations are interpreted using a weak-scattering theory. Least squares solutions for ionospheric parameters derived from the observed fluctuation spectra yield estimates of (1) the axial ratio, (2) angular orientation of the anisotropic irregularities, (3) the power law exponent of the spatial spectrum of irregularities, and (4) the magnitude of the spatial variations in electron density. It is shown that the measured angular orientation of the anisotropic irregularities indicates magnetic field direction and may provide a basis for refining Jovian magnetic field models.

  9. Transition radiation spectra of electrons from 1 to 10 GeV/c in regular and irregular radiators

    International Nuclear Information System (INIS)

    Andronic, A.; Appelshaeuser, H.; Bailhache, R.; Baumann, C.; Braun-Munzinger, P.; Bucher, D.; Busch, O.; Catanescu, V.; Chernenko, S.; Christakoglou, P.; Fateev, O.; Freuen, S.; Garabatos, C.; Gottschlag, H.; Gunji, T.; Hamagaki, H.; Herrmann, N.; Hoppe, M.; Lindenstruth, V.; Lippmann, C.; Morino, Y.; Panebratsev, Yu.; Petridis, A.; Petrovici, M.; Rusanov, I.; Sandoval, A.; Saito, S.; Schicker, R.; Soltveit, H.K.; Stachel, J.; Stelzer, H.; Vassiliou, M.; Vulpescu, B.; Wessels, J.P.; Wilk, A.; Yurevich, V.; Zanevsky, Yu.

    2006-01-01

    We present measurements of the spectral distribution of transition radiation generated by electrons of momentum 1-10 GeV/c in different radiator types. We investigate periodic foil radiators and irregular foam and fiber materials. The transition radiation photons are detected by prototypes of the drift chambers to be used in the Transition Radiation Detector (TRD) of the ALICE experiment at CERN, which are filled with a Xe, CO 2 (15%) mixture. The measurements are compared to simulations in order to enhance the quantitative understanding of transition radiation production, in particular the momentum dependence of the transition radiation yield

  10. Socio-technical transition as a co-evolutionary process: Innovation and the role of niche markets in the transition to motor vehicles

    Science.gov (United States)

    Birky, Alicia K.

    2008-10-01

    Significant reductions in greenhouse emissions from personal transportation will require a transition to an alternative technology regime based on renewable energy sources. Two bodies of research, the quasi-evolutionary (QE) model and the multi-level perspective (MLP) assert that processes within niches play a fundamental role in such transitions. This research asks whether the description of transitions based on this niche hypothesis and its underlying assumptions is consistent with the historical U.S. transition to motor vehicles at the beginning of the 20th century. Unique to this dissertation is the combination of the perspective of the entrepreneur with co-evolutionary approaches to socio-technical transitions. This approach is augmented with concepts from the industry life-cycle model and with a taxonomy of mechanisms of learning. Using this analytic framework, I examine specifically the role of entrepreneurial behavior and processes within and among firms in the co-evolution of technologies and institutions during the transition to motor vehicles. I find that niche markets played an important role in the development of the technology, institutions, and the industry. However, I also find that the diffusion of the automobile is not consistent with the niche hypothesis in the following ways: (1) product improvements and cost reductions were not realized in niche markets, but were achieved simultaneously with diffusion into mass markets; (2) in addition to learning-by-doing and learning-by-interacting with users, knowledge spillovers and interacting with suppliers were critical in this process; (3) cost reductions were not automatic results of expanding markets, but rather arose from the strategies of entrepreneurs based on personal perspectives and values. This finding supports the use of a behavioral approach with a micro-focus in the analysis of socio-technical change. I also find that the emergence and diffusion of the motor vehicle can only be understood by

  11. Extended Schmidt law holds for faint dwarf irregular galaxies

    Science.gov (United States)

    Roychowdhury, Sambit; Chengalur, Jayaram N.; Shi, Yong

    2017-12-01

    Context. The extended Schmidt law (ESL) is a variant of the Schmidt which relates the surface densities of gas and star formation, with the surface density of stellar mass added as an extra parameter. Although ESL has been shown to be valid for a wide range of galaxy properties, its validity in low-metallicity galaxies has not been comprehensively tested. This is important because metallicity affects the crucial atomic-to-molecular transition step in the process of conversion of gas to stars. Aims: We empirically investigate for the first time whether low metallicity faint dwarf irregular galaxies (dIrrs) from the local universe follow the ESL. Here we consider the "global" law where surface densities are averaged over the galactic discs. dIrrs are unique not only because they are at the lowest end of mass and star formation scales for galaxies, but also because they are metal-poor compared to the general population of galaxies. Methods: Our sample is drawn from the Faint Irregular Galaxy GMRT Survey (FIGGS) which is the largest survey of atomic hydrogen in such galaxies. The gas surface densities are determined using their atomic hydrogen content. The star formation rates are calculated using GALEX far ultraviolet fluxes after correcting for dust extinction, whereas the stellar surface densities are calculated using Spitzer 3.6 μm fluxes. The surface densities are calculated over the stellar discs defined by the 3.6 μm images. Results: We find dIrrs indeed follow the ESL. The mean deviation of the FIGGS galaxies from the relation is 0.01 dex, with a scatter around the relation of less than half that seen in the original relation. In comparison, we also show that the FIGGS galaxies are much more deviant when compared to the "canonical" Kennicutt-Schmidt relation. Conclusions: Our results help strengthen the universality of the ESL, especially for galaxies with low metallicities. We suggest that models of star formation in which feedback from previous generations

  12. Irregular Saturnian Moon Lightcurves from Cassini-ISS Observations: Update

    Science.gov (United States)

    Denk, Tilmann; Mottola, S.

    2013-10-01

    Cassini ISS-NAC observations of the irregular moons of Saturn revealed various physical information on these objects. 16 synodic rotational periods: Hati (S43): 5.45 h; Mundilfari (S25): 6.74 h; Suttungr (S23): ~7.4 h; Kari (S45): 7.70 h; Siarnaq (S29): 10.14 h; Tarvos (S21): 10.66 h; Ymir (S19, sidereal period): 11.92220 h ± 0.1 s; Skathi (S27): ~12 h; Hyrrokkin (S44): 12.76 h; Ijiraq (S22): 13.03 h; Albiorix (S26): 13.32 h; Bestla (S39): 14.64 h; Bebhionn (S37): ~15.8 h; Kiviuq (S24): 21.82 h; Thrymr (S30): ~27 h; Erriapus (S28): ~28 h. The average period for the prograde-orbiting moons is ~16 h, for the retrograde moons ~11½ h (includes Phoebe's 9.2735 h from Bauer et al., AJ, 2004). Phase-angle dependent behavior of lightcurves: The phase angles of the observations range from 2° to 105°. The lightcurves which were obtained at low phase (<40°) show the 2-maxima/ 2-minima pattern expected for this kind of objects. At higher phases, more complicated lightcurves emerge, giving rough indications on shapes. Ymir pole and shape: For satellite Ymir, a convex-hull shape model and the pole-axis orientation have been derived. Ymir's north pole points toward λ = 230°±180°, β = -85°±10°, or RA = 100°±20°, Dec = -70°±10°. This is anti-parallel to the rotation axes of the major planets, indicating that Ymir not just orbits, but also rotates in a retrograde sense. The shape of Ymir resembles a triangular prism with edge lengths of ~20, ~24, and ~25 km. The ratio between the longest 25 km) and shortest axis (pole axis, ~15 km) is ~1.7. Erriapus seasons: The pole direction of object Erriapus has probably a low ecliptic latitude. This gives this moon seasons similar to the Uranian regular moons with periods where the sun stands very high in the sky over many years, and with years-long periods of permanent night. Hati density: The rotational frequency of the fastest rotator (Hati) is close to the frequency where the object would lose material from the surface if

  13. ON THE STAR FORMATION LAW FOR SPIRAL AND IRREGULAR GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Elmegreen, Bruce G., E-mail: bge@us.ibm.com [IBM Research Division, T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY 10598 (United States)

    2015-12-01

    A dynamical model for star formation on a galactic scale is proposed in which the interstellar medium is constantly condensing to star-forming clouds on the dynamical time of the average midplane density, and the clouds are constantly being disrupted on the dynamical timescale appropriate for their higher density. In this model, the areal star formation rate scales with the 1.5 power of the total gas column density throughout the main regions of spiral galaxies, and with a steeper power, 2, in the far outer regions and in dwarf irregular galaxies because of the flaring disks. At the same time, there is a molecular star formation law that is linear in the main and outer parts of disks and in dIrrs because the duration of individual structures in the molecular phase is also the dynamical timescale, canceling the additional 0.5 power of surface density. The total gas consumption time scales directly with the midplane dynamical time, quenching star formation in the inner regions if there is no accretion, and sustaining star formation for ∼100 Gyr or more in the outer regions with no qualitative change in gas stability or molecular cloud properties. The ULIRG track follows from high densities in galaxy collisions.

  14. Influence of Ionospheric Irregularities on GNSS Remote Sensing

    Directory of Open Access Journals (Sweden)

    M. V. Tinin

    2015-01-01

    Full Text Available We have used numerical simulation to study the effects of ionospheric irregularities on accuracy of global navigation satellite system (GNSS measurements, using ionosphere-free (in atmospheric research and geometry-free (in ionospheric research dual-frequency phase combinations. It is known that elimination of these effects from multifrequency GNSS measurements is handi-capped by diffraction effects during signal propagation through turbulent ionospheric plasma with the inner scale being smaller than the Fresnel radius. We demonstrated the possibility of reducing the residual ionospheric error in dual-frequency GNSS remote sensing in ionosphere-free combination by Fresnel inversion. The inversion parameter, the distance to the virtual screen, may be selected from the minimum of amplitude fluctuations. This suggests the possibility of improving the accuracy of GNSS remote sensing in meteorology. In the study of ionospheric disturbances with the aid of geometry-free combination, the Fresnel inversion eliminates only the third-order error. To eliminate the random TEC component which, like the measured average TEC, is the first-order correction, we should use temporal filtering (averaging.

  15. Timing irregularities of PSR J1705-1906

    Science.gov (United States)

    Liu, Y. L.; Yuan, J. P.; Wang, J. B.; Liu, X. W.; Wang, N.; Yuen, R.

    2018-05-01

    Timing analysis of PSR J1705-1906 using data from Nanshan 25-m and Parkes 64-m radio telescopes, which span over fourteen years, shows that the pulsar exhibits significant proper motion, and rotation instability. We updated the astrometry parameters and the spin parameters of the pulsar. In order to minimize the effect of timing irregularities on measuring its position, we employ the Cholesky method to analyse the timing noise. We obtain the proper motion of -77(3) mas yr-1 in right ascension and -38(29) mas yr-1 in declination. The power spectrum of timing noise is analyzed for the first time, which gives the spectral exponent α =-5.2 for the power-law model indicating that the fluctuations in spin frequency and spin-down rate dominate the red noise. We detect two small glitches from this pulsar with fractional jump in spin frequency of Δ ν /ν ˜ 2.9 × 10^{-10} around MJD 55199 and Δ ν /ν ˜ 2.7× 10^{-10} around MJD 55953. Investigations of pulse profile at different time segments suggest no significant changes in the pulse profiles around the two glitches.

  16. Distributed sensing of ionospheric irregularities with a GNSS receiver array

    Science.gov (United States)

    Su, Yang; Datta-Barua, Seebany; Bust, Gary S.; Deshpande, Kshitija B.

    2017-08-01

    We present analysis methods for studying the structuring and motion of ionospheric irregularities at the subkilometer scale sizes that produce L band scintillations. Spaced-receiver methods are used for Global Navigation Satellite System (GNSS) receivers' phase measurements over approximately subkilometer to kilometer length baselines for the first time. The quantities estimated by these techniques are plasma drift velocity, diffraction anisotropy magnitude and orientation, and characteristic velocity. Uncertainties are quantified by ensemble simulation of noise on the phase signals carried through to the observations of the spaced-receiver linear system. These covariances are then propagated through to uncertainties on drifts through linearization about the estimated values of the state. Five receivers of SAGA, the Scintillation Auroral Global Positioning System (GPS) Array, provide 100 Hz power and phase data for each channel at L1 frequency. The array is sited in the auroral zone at Poker Flat Research Range, Alaska. A case study of a single scintillating satellite observed by the array is used to demonstrate the spaced-receiver and uncertainty estimation process. A second case study estimates drifts as measured by multiple scintillating channels. These scintillations are correlated with auroral activity, based on all-sky camera images. Measurements and uncertainty estimates made over a 30 min period are compared to a collocated incoherent scatter radar and show good agreement in horizontal drift speed and direction during periods of scintillation for which the characteristic velocity is less than the drift velocity.

  17. Metallicity of Young and Old Stars in Irregular Galaxies

    Science.gov (United States)

    Tikhonov, N. A.

    2018-01-01

    Based on archived images obtained with the Hubble Space Telescope, stellar photometry for 105 irregular galaxies has been conducted. We have shown the red supergiant and giant branches in the obtained Hertzsprung-Russel diagrams. Using the TRGB method, distances to galaxies and metallicity of red giants have been determined. The color index ( V - I) of the supergiant branch at the luminosity level M I = -7 was chosen as the metallicity index of red supergiants. For the galaxies under study, the diagrams have been built, in which the correlation can be seen between the luminosity of galaxies ( M B ) and metallicity of red giants and supergiants. The main source of variance of the results in the obtained diagrams is, in our opinion, uncertainty inmeasurements of galaxy luminosities and star-forming outburst. The relation between metallicity of young and old stars shows that main enrichment of galaxies with metals has taken place in the remote past. Deviations of some galaxies in the obtained relation can possibly be explained with the fall of the intergalactic gas on them, although, this inconsiderably affects metallicities of the stellar content.

  18. Climatic irregular staircases: generalized acceleration of global warming.

    Science.gov (United States)

    De Saedeleer, Bernard

    2016-01-27

    Global warming rates mentioned in the literature are often restricted to a couple of arbitrary periods of time, or of isolated values of the starting year, lacking a global view. In this study, we perform on the contrary an exhaustive parametric analysis of the NASA GISS LOTI data, and also of the HadCRUT4 data. The starting year systematically varies between 1880 and 2002, and the averaging period from 5 to 30 yr - not only decades; the ending year also varies . In this way, we uncover a whole unexplored space of values for the global warming rate, and access the full picture. Additionally, stairstep averaging and linear least squares fitting to determine climatic trends have been sofar exclusive. We propose here an original hybrid method which combines both approaches in order to derive a new type of climatic trend. We find that there is an overall acceleration of the global warming whatever the value of the averaging period, and that 99.9% of the 3029 Earth's climatic irregular staircases are rising. Graphical evidence is also given that choosing an El Niño year as starting year gives lower global warming rates - except if there is a volcanic cooling in parallel. Our rates agree and generalize several results mentioned in the literature.

  19. Propagating star formation and irregular structure in spiral galaxies

    International Nuclear Information System (INIS)

    Mueller, M.W.; Arnett, W.D.

    1976-01-01

    A simple model is proposed which describes the irregular optical appearance often seen in late-type spiral galaxies. If high-mass stars produce spherical shock waves which induce star formation, new high-mass stars will be born which, in turn, produce new shock waves. When this process operates in a differentially rotating disk, our numerical model shows that large-scale spiral-shaped regions of star formation are built up. The structure is seen to be most sensitive to a parameter which governs how often a region of the interstellar medium can undergo star formation. For a proper choice of this parameter, large-scale features disappear before differential rotation winds them up. New spiral features continuously form, so some spiral structure is seen indefinitely. The structure is not the classical two-armed symmetric spiral pattern which the density-wave theory attempts to explain, but it is asymmetric and disorderly.The mechanism of propagating star formation used in our model is consistent with observations which connect young OB associations with expanding shells of gas. We discuss the possible interaction of this mechanism with density waves

  20. Effects of Irregular Bridge Columns and Feasibility of Seismic Regularity

    Science.gov (United States)

    Thomas, Abey E.

    2018-05-01

    Bridges with unequal column height is one of the main irregularities in bridge design particularly while negotiating steep valleys, making the bridges vulnerable to seismic action. The desirable behaviour of bridge columns towards seismic loading is that, they should perform in a regular fashion, i.e. the capacity of each column should be utilized evenly. But, this type of behaviour is often missing when the column heights are unequal along the length of the bridge, allowing short columns to bear the maximum lateral load. In the present study, the effects of unequal column height on the global seismic performance of bridges are studied using pushover analysis. Codes such as CalTrans (Engineering service center, earthquake engineering branch, 2013) and EC-8 (EN 1998-2: design of structures for earthquake resistance. Part 2: bridges, European Committee for Standardization, Brussels, 2005) suggests seismic regularity criterion for achieving regular seismic performance level at all the bridge columns. The feasibility of adopting these seismic regularity criterions along with those mentioned in literatures will be assessed for bridges designed as per the Indian Standards in the present study.

  1. Weighted statistical parameters for irregularly sampled time series

    Science.gov (United States)

    Rimoldini, Lorenzo

    2014-01-01

    Unevenly spaced time series are common in astronomy because of the day-night cycle, weather conditions, dependence on the source position in the sky, allocated telescope time and corrupt measurements, for example, or inherent to the scanning law of satellites like Hipparcos and the forthcoming Gaia. Irregular sampling often causes clumps of measurements and gaps with no data which can severely disrupt the values of estimators. This paper aims at improving the accuracy of common statistical parameters when linear interpolation (in time or phase) can be considered an acceptable approximation of a deterministic signal. A pragmatic solution is formulated in terms of a simple weighting scheme, adapting to the sampling density and noise level, applicable to large data volumes at minimal computational cost. Tests on time series from the Hipparcos periodic catalogue led to significant improvements in the overall accuracy and precision of the estimators with respect to the unweighted counterparts and those weighted by inverse-squared uncertainties. Automated classification procedures employing statistical parameters weighted by the suggested scheme confirmed the benefits of the improved input attributes. The classification of eclipsing binaries, Mira, RR Lyrae, Delta Cephei and Alpha2 Canum Venaticorum stars employing exclusively weighted descriptive statistics achieved an overall accuracy of 92 per cent, about 6 per cent higher than with unweighted estimators.

  2. Irregular persistent activity induced by synaptic excitatory feedback

    Directory of Open Access Journals (Sweden)

    Francesca Barbieri

    2007-11-01

    Full Text Available Neurophysiological experiments on monkeys have reported highly irregular persistent activity during the performance of an oculomotor delayed-response task. These experiments show that during the delay period the coefficient of variation (CV of interspike intervals (ISI of prefrontal neurons is above 1, on average, and larger than during the fixation period. In the present paper, we show that this feature can be reproduced in a network in which persistent activity is induced by excitatory feedback, provided that (i the post-spike reset is close enough to threshold , (ii synaptic efficacies are a non-linear function of the pre-synaptic firing rate. Non-linearity between presynaptic rate and effective synaptic strength is implemented by a standard short-term depression mechanism (STD. First, we consider the simplest possible network with excitatory feedback: a fully connected homogeneous network of excitatory leaky integrate-and-fire neurons, using both numerical simulations and analytical techniques. The results are then confirmed in a network with selective excitatory neurons and inhibition. In both the cases there is a large range of values of the synaptic efficacies for which the statistics of firing of single cells is similar to experimental data.

  3. "Needed Not Wanted": An Interdisciplinary Examination of the Work-Related Challenges Faced by Irregular Migrants

    Science.gov (United States)

    Marfleet, Philip; Blustein, David L.

    2011-01-01

    Using an integrative perspective drawn from vocational psychology and migration studies, this article explores the lives of irregular migrants, which represents a unique aspect of work-based migration. Irregular migrants are those individuals who travel from regions without much work to states that offer some means of employment, without formal…

  4. Lateralized effects of orthographical irregularity and auditory memory load on the kinematics of transciption typewriting

    NARCIS (Netherlands)

    Bloemsaat, J.G.; Galen, G.P. van; Meulenbroek, R.G.J.

    2003-01-01

    This study investigated the combined effects of orthographical irregularity and auditory memory load on the kinematics of finger movements in a transcription-typewriting task. Eight right-handed touch-typists were asked to type 80 strings of ten seven-letter words. In half the trials an irregularly

  5. The Relationships among Cognitive Correlates and Irregular Word, Non-Word, and Word Reading

    Science.gov (United States)

    Abu-Hamour, Bashir; University, Mu'tah; Urso, Annmarie; Mather, Nancy

    2012-01-01

    This study explored four hypotheses: (a) the relationships among rapid automatized naming (RAN) and processing speed (PS) to irregular word, non-word, and word reading; (b) the predictive power of various RAN and PS measures, (c) the cognitive correlates that best predicted irregular word, non-word, and word reading, and (d) reading performance of…

  6. Influence of initial stress, irregularity and heterogeneity on Love-type ...

    Indian Academy of Sciences (India)

    The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half- space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface.

  7. Crime among irregular immigrants and the influence of internal border control

    NARCIS (Netherlands)

    Leerkes, A.S.; Engbersen, G.; Leun, van der J.P.

    2012-01-01

    Abstract Both the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular immigrants

  8. Crime among irregular immigrants and the influence of internal border control

    NARCIS (Netherlands)

    A.S. Leerkes (Arjen); G.B.M. Engbersen (Godfried); J.P. van der Leun (Joanne)

    2012-01-01

    textabstractBoth the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular

  9. Breaking Down Anonymity: Digital surveillance on irregular migrants in Germany and the Netherlands

    NARCIS (Netherlands)

    D.W.J. Broeders (Dennis)

    2009-01-01

    textabstractThe presence of irregular migrants causes a tough problem for policy makers. Political and popular aversion against the presence of irregular migrants has mounted in most West-European societies for years, yet their presence remains. Their exact numbers are obviously unknown - only

  10. Dynamics of long-period irregular pulsations in high latitudes during strong magnetic storms

    International Nuclear Information System (INIS)

    Kurazhkovskaya, N.A.; Klajn, B.I.

    1995-01-01

    Effects of strong magnetic storms within np type high-latitudinal long-period irregular pulsations at Mirny studied using data obtained at observatory of the magnetosphere south hemisphere. Variation of long-period irregular pulsation amplitude is shown to depend essentially on duration of storm initial phase and on the nature of solar wind heterogeneity enabling growth of strong storm. 14 refs

  11. Spectral classification of medium-scale high-latitude F region plasma density irregularities

    International Nuclear Information System (INIS)

    Singh, M.; Rodriguez, P.; Szuszczewicz, E.P.; Sachs Freeman Associates, Bowie, MD)

    1985-01-01

    The high-latitude ionosphere represents a highly structured plasma. Rodriguez and Szuszczewicz (1984) reported a wide range of plasma density irregularities (150 km to 75 m) at high latitudes near 200 km. They have shown that the small-scale irregularities (7.5 km to 75 m) populated the dayside oval more often than the other phenomenological regions. It was suggested that in the lower F region the chemical recombination is fast enough to remove small-scale irregularities before convection can transport them large distances, leaving structured particle precipitation as the dominant source term for irregularities. The present paper provides the results of spectral analyses of pulsed plasma probe data collected in situ aboard the STP/S3-4 satellite during the period March-September 1978. A quantitative description of irregularity spectra in the high-latitude lower F region plasma density is given. 22 references

  12. Low and Mid-Latitude Ionospheric Irregularities Studies Using TEC and Radio Scintillation Data from the CITRIS Radio Beacon Receiver in Low-Earth-Orbit

    Science.gov (United States)

    Siefring, C. L.; Bernhardt, P. A.; Huba, J.; Krall, J.; Roddy, P. A.

    2009-12-01

    Unique data on ionospheric plasma irregularities from the Naval Research Laboratory (NRL) CITRIS (Scintillation and TEC Receiver in Space) instrument will be presented. CITRIS is a multi-band receiver that recorded TEC (Total Electron Content) and radio scintillations from Low-Earth Orbit (LEO) on STPSat1. The 555+/5 km altitude 35° inclination orbit covers low and mid-latitudes. The measurements require propagation from a transmitter to a receiver through the F-region plasma. CITRIS used both 1) satellite beacons in LEO, such as the NRL CERTO (Coherent Electromagnetic Radio TOmography) beacons and 2) the global network of ground-based DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) beacons. The TEC measurements allow for tracking of ionospheric disturbances and irregularities while the measurements of scintillations can simultaneously characterize their effects. CITRIS was operated in a complementary fashion with the C/NOFS (Communication/Navigations Outages Forecasting System) satellite during most of its first year of operations. C/NOFS carries a three-frequency 150/400/1067 MHz CERTO beacon and is dedicated to the study of Spread-F. In the case of Spread-F, ionospheric irregularities start with large scale size density gradients (100s of km) and cascade through complex processes to short scale sizes (10s of meters). It is typically the 100m-1km scale features that harm communication and navigation systems through scintillations. A multi-sensor approach is needed to completely understand this complex system, such as, the combination of CITRIS remote radio sensing and C/NOFS in-situ data. Several types of irregularities have been studied including Spread-F and the newly discovered dawn-side depletions. Comparisons with the physics based SAMI3 model are being performed to help our understanding of the morphology of the irregularities.

  13. New Opportunities for Remote Sensing Ionospheric Irregularities by Fitting Scintillation Spectra

    Science.gov (United States)

    Carrano, C. S.; Rino, C. L.; Groves, K. M.

    2017-12-01

    In a recent paper, we presented a phase screen theory for the spectrum of intensity scintillations when the refractive index irregularities follow a two-component power law [Carrano and Rino, DOI: 10.1002/2015RS005903]. More recently we have investigated the inverse problem, whereby phase screen parameters are inferred from scintillation time series. This is accomplished by fitting the spectrum of intensity fluctuations with a parametrized theoretical model using Maximum Likelihood (ML) methods. The Markov-Chain Monte-Carlo technique provides a-posteriori errors and confidence intervals. The Akaike Information Criterion (AIC) provides justification for the use of one- or two-component irregularity models. We refer to this fitting as Irregularity Parameter Estimation (IPE) since it provides a statistical description of the irregularities from the scintillations they produce. In this talk, we explore some new opportunities for remote sensing ionospheric irregularities afforded by IPE. Statistical characterization of irregularities and the plasma bubbles in which they are embedded provides insight into the development of the underlying instability. In a companion paper by Rino et al., IPE is used to interpret scintillation due to simulated EPB structure. IPE can be used to reconcile multi-frequency scintillation observations and to construct high fidelity scintillation simulation tools. In space-to-ground propagation scenarios, for which an estimate of the distance to the scattering region is available a-priori, IPE enables retrieval of zonal irregularity drift. In radio occultation scenarios, the distance to the irregularities is generally unknown but IPE enables retrieval of Fresnel frequency. A geometric model for the effective scan velocity maps Fresnel frequency to Fresnel scale, yielding the distance to the irregularities. We demonstrate this approach by geolocating irregularities observed by the CORISS instrument onboard the C/NOFS satellite.

  14. Irregular Morphing for Real-Time Rendering of Large Terrain

    Directory of Open Access Journals (Sweden)

    S. Kalem

    2016-06-01

    Full Text Available The following paper proposes an alternative approach to the real-time adaptive triangulation problem. A new region-based multi-resolution approach for terrain rendering is described which improves on-the-fly the distribution of the density of triangles inside the tile after selecting appropriate Level-Of-Detail by an adaptive sampling. This proposed approach organizes the heightmap into a QuadTree of tiles that are processed independently. This technique combines the benefits of both Triangular Irregular Network approach and region-based multi-resolution approach by improving the distribution of the density of triangles inside the tile. Our technique morphs the initial regular grid of the tile to deformed grid in order to minimize approximation error. The proposed technique strives to combine large tile size and real-time processing while guaranteeing an upper bound on the screen space error. Thus, this approach adapts terrain rendering process to local surface characteristics and enables on-the-fly handling of large amount of terrain data. Morphing is based-on the multi-resolution wavelet analysis. The use of the D2WT multi-resolution analysis of the terrain height-map speeds up processing and permits to satisfy an interactive terrain rendering. Tests and experiments demonstrate that Haar B-Spline wavelet, well known for its properties of localization and its compact support, is suitable for fast and accurate redistribution. Such technique could be exploited in client-server architecture for supporting interactive high-quality remote visualization of very large terrain.

  15. TINITALY/01: a new Triangular Irregular Network of Italy

    Directory of Open Access Journals (Sweden)

    M. T. Pareschi

    2007-06-01

    Full Text Available A new Digital Elevation Model (DEM of the natural landforms of Italy is presented. A methodology is discussed to build a DEM over wide areas where elevation data from non-homogeneous (in density and accuracy input sources are available. The input elevation data include contour lines and spot heights derived from the Italian Regional topographic maps, satellite-based global positioning system points, ground based and radar altimetry data. Owing to the great heterogeneity of the input data density, the DEM format that better preserves the original accuracy is a Triangular Irregular Network (TIN. A Delaunay-based TIN structure is improved by using the DEST algorithm that enhances input data by evaluating inferred break-lines. Accordingly to this approach, biased distributions in slopes and elevations are absent. To prevent discontinuities at the boundary between regions characterized by data with different resolution a cubic Hermite blending weight S-shaped function is adopted. The TIN of Italy consists of 1.39×109 triangles. The average triangle area ranges from 12 to about 13000 m2 accordingly to different morphologies and different sources. About 50% of the model has a local average triangle area <500 m2. The vertical accuracy of the obtained DEM is evaluated by more than 200000 sparse control points. The overall Root Mean Square Error (RMSE is less than 3.5 m. The obtained national-scale DEM constitutes an useful support to carry out accurate geomorphological and geological investigations over large areas. The problem of choosing the best step size in deriving a grid from a TIN is then discussed and a method to quantify the loss of vertical information is presented as a function of the grid step. Some examples of DEM application are outlined. Under request, an high resolution stereo image database of the whole Italian territory (derived from the presented DEM is available to browse via internet.

  16. Periods, poles, and shapes of Saturn's irregular moons

    Science.gov (United States)

    Denk, Tilmann; Mottola, Stefano

    2016-10-01

    We report rotational-lightcurve observations of irregular moons of Saturn based on disk-integrated observations with the Narrow-Angle Camera of the Cassini spacecraft. From 24 measured rotation periods, 20 are now known with an accuracy of ~2% or better. The numbers are as follows (in hours; an '*' marks the less reliable periods): Hati 5.42; Mundilfari 6.74; Loge 6.94*; Skoll 7.26; Kari 7.70; Suttungr 7.82*, Bergelmir 8.13; Phoebe 9.274; Siarnaq 10.188; Narvi 10.21; Tarvos 10.69; Skathi 11.30; Ymir 11.922; Hyrrokkin 12.76; Greip 12.79*; Ijiraq 13.03; Albiorix 13.32; Bestla 14.624; Bebhionn 16.40; Paaliaq 18.75; Kiviuq 21.96; Erriapus 28.15; Thrymr 35 or >45* Tarqeq 76.8.More recent data strengthen the notion that objects in orbits with an inclination supplemental angle i' > 27° have significantly slower spin rates than those at i' 27°, Siarnaq, stands opposed to at least eight objects with faster spins and i' 27° bin contains all nine known prograde moons and four retrograde objects.A total of 25 out of 38 known outer moons has been observed with Cassini, and there is no chance to observe the 13 missing objects until end-of-mission. However, all unobserved objects are part of the i' 27° are known, and none of them is a fast rotator, with no exception.Several objects were observed repeatedly to determine pole directions, sidereal periods, and convex shapes. A few lightcurves have been observed to show three maxima and three minima even at low phase angles, suggesting objects with a triangular equatorial cross-section. Some objects with 2 maxima/ 2 minima are probably quite elongated. One moon even shows lightcurves with 4 maxima/ 4 minima.

  17. THE MEASUREMENT METHODOLOGY IMPROVEMENT OF THE HORIZONTAL IRREGULARITIES IN PLAN

    Directory of Open Access Journals (Sweden)

    O. M. Patlasov

    2015-08-01

    Full Text Available Purpose. Across the track superstructure (TSS there are structures where standard approach to the decision on the future of their operation is not entirely correct or acceptable. In particular, it concerns the track sections which are sufficiently quickly change their geometric parameters: the radius of curvature, angle of rotation, and the like. As an example, such portions of TSS may include crossovers where their component is within the so-called connecting part, which at a sufficiently short length, substantially changes curvature. The estimation of the position in terms of a design on the basis of the existing technique (by the difference in the adjacent arrows bending is virtually impossible. Therefore it is proposed to complement and improve the methodology for assessing the situation of the curve in plan upon difference in the adjacent versine. Methodology. The possible options for measuring horizontal curves in the plan were analyzed. The most adequate method, which does not contradict existing on the criterion of the possibility of using established standards was determined. The ease of measurement and calculation was took into account. Findings. Qualitative and quantitative verification of the proposed and existing methods showed very good agreement of the measurement results. This gives grounds to assert that this methodology can be recommended to the workers of track facilities in the assessment of horizontal irregularities in plan not only curves, but also within the connecting part of switch congresses. Originality. The existing method of valuation of the geometric position of the curves in the plan was improved. It does not create new regulations, and all results are evaluated by existing norms. Practical value. The proposed technique makes it possible, without creating a new regulatory framework, to be attached to existing one, and expanding the boundaries of its application. This method can be used not only for ordinary curves

  18. Contribution of tropical instability waves to ENSO irregularity

    Science.gov (United States)

    Holmes, Ryan M.; McGregor, Shayne; Santoso, Agus; England, Matthew H.

    2018-05-01

    Tropical instability waves (TIWs) are a major source of internally-generated oceanic variability in the equatorial Pacific Ocean. These non-linear phenomena play an important role in the sea surface temperature (SST) budget in a region critical for low-frequency modes of variability such as the El Niño-Southern Oscillation (ENSO). However, the direct contribution of TIW-driven stochastic variability to ENSO has received little attention. Here, we investigate the influence of TIWs on ENSO using a 1/4° ocean model coupled to a simple atmosphere. The use of a simple atmosphere removes complex intrinsic atmospheric variability while allowing the dominant mode of air-sea coupling to be represented as a statistical relationship between SST and wind stress anomalies. Using this hybrid coupled model, we perform a suite of coupled ensemble forecast experiments initiated with wind bursts in the western Pacific, where individual ensemble members differ only due to internal oceanic variability. We find that TIWs can induce a spread in the forecast amplitude of the Niño 3 SST anomaly 6-months after a given sequence of WWBs of approximately ± 45% the size of the ensemble mean anomaly. Further, when various estimates of stochastic atmospheric forcing are added, oceanic internal variability is found to contribute between about 20% and 70% of the ensemble forecast spread, with the remainder attributable to the atmospheric variability. While the oceanic contribution to ENSO stochastic forcing requires further quantification beyond the idealized approach used here, our results nevertheless suggest that TIWs may impact ENSO irregularity and predictability. This has implications for ENSO representation in low-resolution coupled models.

  19. METAL ABUNDANCES OF 12 DWARF IRREGULARS FROM THE ADBS SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Haurberg, Nathalie C.; Salzer, John J. [Department of Astronomy, Indiana University, 727 E. Third St., Bloomington, IN 47405 (United States); Rosenberg, Jessica, E-mail: nhaurber@astro.indiana.edu, E-mail: slaz@astro.indiana.edu, E-mail: jrosenb4@gmu.edu [School of Physics, Astronomy and Computational Science, George Mason University, MS 3F3, Fairfax, VA 22030 (United States)

    2013-03-01

    We have analyzed long-slit spectra of 12 dwarf irregular galaxies from the Arecibo Dual Beam Survey (ADBS). These galaxies represent a heterogeneous sample of objects detected by ADBS, but on average are relatively gas-rich, low-surface-brightness, and low-mass, thus represent a region of the galaxian population that is not commonly included in optical surveys. The metallicity-luminosity relationship for these galaxies is analyzed; the galaxies discussed in this paper appear to be under-abundant at a given luminosity when compared to a sample from the literature. We attempt to identify a 'second parameter' responsible for the intrinsic scatter and apparent under-abundance of our galaxies. We do not find a definitive second parameter but note the possible indication that infall or mixing of pristine gas may be responsible. We derive oxygen abundances for multiple H II regions in many of our galaxies but do not find any strong indications of metallicity variation within the galaxies except in one case where we see variation between an isolated H II region and the rest of the galaxy. Our data set includes the galaxy with the largest known H I-to-optical size ratio, ADBS 113845+2008. Our abundance analysis of this galaxy reveals that it is strongly over-enriched compared to galaxies of similar luminosity, indicating it is not a young object and confirming the result from Cannon et al. that this galaxy appears to be intrinsically rare in the local universe.

  20. Ionospheric irregularities at low latitudes in the American sector

    International Nuclear Information System (INIS)

    Nakamura, Y.

    1981-10-01

    A detailed analysis of the atomic oxigem airglow emission at the wavelength of 6300 A observed at Cachoeira Paulista (22 0 41'S, 45 0 00'W) shows that intensity perturbations frequently occur and propagate from north to south and from west to east. Such irregularities originated in the ionospheric F region and occur essencially during the premidnight period. These perturbations have a high frequency of occurrence during spring and summer and are rare during winter and fall. The disturbances are correlated with range type spread F detected over Cachoeira Paulista, and have characteristics similar to equatorial ionospheric plasma bubbles (i.e., similar seazonal variation, time of occurrence, ionogram signatures, direction and speed of propagation, etc.). A numerical simulation is carried out for the generation and evolution of ionospheric bubbles based on the theory of the collisional Rayleigh-Taylor instability for the equatorial and Cachoeira Paulista regions. Also a study was made of the, evolution of the bubble as a function of the electron density profile and as a function of the amplitude of the initial density perturbation. Assuming the electron density profile perturbed by the bubble, the [OI] 6300 A intensity was calculated for various latitudes arbitrarily taken within the photometer scanning range. The bubble was assumed to be aligned with the Earth's magnetic field and extending from higher altitudes at the equatorial region down to be arbitrary height of 150 Km at which a negligible conductivity is assumed. It was also assumed that the bubble was moving upwards with the velocity of 120 m/s, which in turn was estimated from initial numerical simulation results. The airglow calculation results show that as the bubble goes up, the disturbances in the airglow intensity propagate from north to south, in accord with observed experimental results. (Author) [pt

  1. Plasma Irregularity Production in the Polar Cap F-Region Ionosphere

    Science.gov (United States)

    Lamarche, Leslie

    Plasma in the Earth's ionosphere is highly irregular on scales ranging between a few centimeters and hundreds of kilometers. Small-scale irregularities or plasma waves can scatter radio waves resulting in a loss of signal for navigation and communication networks. The polar region is particularly susceptible to strong disturbances due to its direct connection with the Sun's magnetic field and energetic particles. In this thesis, factors that contribute to the production of decameter-scale plasma irregularities in the polar F region ionosphere are investigated. Both global and local control of irregularity production are studied, i.e. we consider global solar control through solar illumination and solar wind as well as much more local control by plasma density gradients and convection electric field. In the first experimental study, solar control of irregularity production is investigated using the Super Dual Auroral Radar Network (SuperDARN) radar at McMurdo, Antarctica. The occurrence trends for irregularities are analyzed statistically and a model is developed that describes the location of radar echoes within the radar's field-of-view. The trends are explained through variations in background plasma density with solar illumination affecting radar beam propagation. However, it is found that the irregularity occurrence during the night is higher than expected from ray tracing simulations based on a standard ionospheric density model. The high occurrence at night implies an additional source of plasma density and it is proposed that large-scale density enhancements called polar patches may be the source of this density. Additionally, occurrence maximizes around the terminator due to different competing irregularity production processes that favor a more or less sunlit ionosphere. The second study is concerned with modeling irregularity characteristics near a large-scale density gradient reversal, such as those expected near polar patches, with a particular focus on

  2. Spatial irregularities in Jupiter's upper ionosphere observed by voyager radio occultations

    Energy Technology Data Exchange (ETDEWEB)

    Hinson, D.P.; Tyler, G.L.

    1982-07-01

    Dual frequency radio occultation experiments carried out with Voyagers 1 and 2 provided data on the spatial irregularities in Jupiter's ionosphere at four different locations. Sample spectra of weak fluctuations in amplitude and phase of the 3.6-cm and 13-cm wavelength radio signals can be interpreted by using the theory for scattering from an anisotropic power law phase screen. Least squares solutions for ionospheric parameters derived from the observed fluctuation spectra yielded estimates of (1) the axial ratio, (2) angular orientation of the anisotropic irregularities, (3) the power law exponent of the spatial spectrum of irregularities, and (4) the magnitude of the spatial variations in electron density. Equipment limitations and the method of analysis constrain the observations to irregularities of approximate size 1--200 km. No evidence of the inner or outer scale of the irregularities was found. For length scales in the range given, the three-dimensional spatial spectrum obeys a power law with exponent varying from -3.0 to -3.7, and the root mean square fractional variations in electron density are 1--15%. All observed irregularities appear to be anisotropic with axial ratios between 2:1 and 10:1. Ionospheric parameters vary with altitude and latitude. We conclude that the measured angular orientation of the anisotropic irregularities indicates magnetic field direction and may provide a basis for refining Jovian magnetic field models.

  3. Exploring performance and energy tradeoffs for irregular applications: A case study on the Tilera many-core architecture

    Energy Technology Data Exchange (ETDEWEB)

    Panyala, Ajay; Chavarría-Miranda, Daniel; Manzano, Joseph B.; Tumeo, Antonino; Halappanavar, Mahantesh

    2017-06-01

    High performance, parallel applications with irregular data accesses are becoming a critical workload class for modern systems. In particular, the execution of such workloads on emerging many-core systems is expected to be a significant component of applications in data mining, machine learning, scientific computing and graph analytics. However, power and energy constraints limit the capabilities of individual cores, memory hierarchy and on-chip interconnect of such systems, thus leading to architectural and software trade-os that must be understood in the context of the intended application’s behavior. Irregular applications are notoriously hard to optimize given their data-dependent access patterns, lack of structured locality and complex data structures and code patterns. We have ported two irregular applications, graph community detection using the Louvain method (Grappolo) and high-performance conjugate gradient (HPCCG), to the Tilera many-core system and have conducted a detailed study of platform-independent and platform-specific optimizations that improve their performance as well as reduce their overall energy consumption. To conduct this study, we employ an auto-tuning based approach that explores the optimization design space along three dimensions - memory layout schemes, GCC compiler flag choices and OpenMP loop scheduling options. We leverage MIT’s OpenTuner auto-tuning framework to explore and recommend energy optimal choices for different combinations of parameters. We then conduct an in-depth architectural characterization to understand the memory behavior of the selected workloads. Finally, we perform a correlation study to demonstrate the interplay between the hardware behavior and application characteristics. Using auto-tuning, we demonstrate whole-node energy savings and performance improvements of up to 49:6% and 60% relative to a baseline instantiation, and up to 31% and 45:4% relative to manually optimized variants.

  4. Proper Elements and Secular Resonances for Irregular Satellites

    Science.gov (United States)

    Beaugé, C.; Nesvorný, D.

    2007-06-01

    We present results of an analytical study of proper elements and secular resonances for the irregular satellites of the outer planets. In the case of the Jovian system we identify three satellite families, two of them previously known (Carme and Ananke), plus a new agglomeration of four bodies that includes Pasiphae as its largest member. While the distribution of proper elements for Saturn's moons seems to be more random, a small cluster was found for the direct moons formed by Albiorix, Erriapo, and 2004 S1, slightly different from the so-called Gaulish cluster. No significant families are detected in the present study for the Uranian or Neptunian satellite systems. For each satellite system we determine the location of several secular resonances in the proper element space. Apart from the well-known resonance locks of Pasiphae, Sinope, and Siarnaq, a comparison between the resonance locations and proper elements shows that Saturn's satellite Narvi also exhibits temporary librations in the ϖ-ϖsolar resonance. However, unlike the resonant Jovian moons that are located in the same configuration, Narvi's critical argument librates alternately around values near 90° and 270°. Neither the Uranian nor Neptunian systems seem to have resonant moons. The resonant dynamics of the real satellites in the vicinity of ϖ˙-ϖ˙solar=0 is studied with a simple model for secular resonances based on the restricted three-body problem. Depending on the initial conditions, we show the existence of one or two modes of libration that can occur at different values of the critical angle, showing a good correspondence with the observed behavior of all the resonant moons. Finally, we discuss the global distribution of the real satellites with respect to the secular resonances, as compared with synthetic populations of bodies drawn solely from stability conditions. For Saturn, we find that the present satellite population appears compatible with simple random distributions. Although

  5. The dynamics of rings around small, irregular bodies

    Science.gov (United States)

    Sicardy, Bruno

    2017-06-01

    Stellar occultations revealed the presence of two dense rings around the Centaur object (10199) Chariklo (Braga-Ribas et al., Nature 508, 72, 2014). This is the first ring system discovered around an object that is not a giant planet, suggesting that rings may exist around numerous bodies in the solar system. Chariklo's rings roughly reside at the outer limit of the Roche zone of the body. Moreover, the main ring has sharp edges, which call for the presence of putative shepherd satellites. Those characteristics give an image of Chariklo's rings that are rather similar, in terms of dynamics, to those surrounding the gaseous planets.An important difference exists, however, between giant planets and small bodies: the formers are highly axisymmetric, while the latters can support mass anomalies (eg surface topographic features) or non-spherical shapes (eg an ellipsoidal figure of equilibrium) that involve masses, relative to the body itself, as large as 10-4-10-3.We investigate the effect of non-axisymmetric terms in the potential of the body upon a collisional debris disk that initially surrounds a small irregular body. We show that the corotation points being maxima of energy, dissipative collisions remove the particles from the corotation zone over short time scales (< 106 years). Moreover, the Lindblad resonances inside the corotation radius create torques that drive the particles onto the surface of the central body. Conversely, the outer Lindblad resonances push the disk material beyond the outer 3/2 and 2/1 Lindblad resonances.Taking as an example Chariklo's ring system, for which recent data have been obtained from stellar occultations, we show that the Lindblad resonant torques actuate over short time scales (< 106 years). This general picture offers a natural explanation of the presence of dense rings at the outer limit of Chariklo's Roche zone, and their absence closer to the body.The work leading to this results has received funding from the European

  6. Dynamic stability of passive dynamic walking on an irregular surface.

    Science.gov (United States)

    Su, Jimmy Li-Shin; Dingwell, Jonathan B

    2007-12-01

    Falls that occur during walking are a significant health problem. One of the greatest impediments to solve this problem is that there is no single obviously "correct" way to quantify walking stability. While many people use variability as a proxy for stability, measures of variability do not quantify how the locomotor system responds to perturbations. The purpose of this study was to determine how changes in walking surface variability affect changes in both locomotor variability and stability. We modified an irreducibly simple model of walking to apply random perturbations that simulated walking over an irregular surface. Because the model's global basin of attraction remained fixed, increasing the amplitude of the applied perturbations directly increased the risk of falling in the model. We generated ten simulations of 300 consecutive strides of walking at each of six perturbation amplitudes ranging from zero (i.e., a smooth continuous surface) up to the maximum level the model could tolerate without falling over. Orbital stability defines how a system responds to small (i.e., "local") perturbations from one cycle to the next and was quantified by calculating the maximum Floquet multipliers for the model. Local stability defines how a system responds to similar perturbations in real time and was quantified by calculating short-term and long-term local exponential rates of divergence for the model. As perturbation amplitudes increased, no changes were seen in orbital stability (r(2)=2.43%; p=0.280) or long-term local instability (r(2)=1.0%; p=0.441). These measures essentially reflected the fact that the model never actually "fell" during any of our simulations. Conversely, the variability of the walker's kinematics increased exponentially (r(2)>or=99.6%; psimulated conditions, the walker remained orbitally stable, while exhibiting substantial local instability. This was because very small initial perturbations diverged away from the limit cycle, while larger

  7. X-ray pulsars in nearby irregular galaxies

    Science.gov (United States)

    Yang, Jun

    2018-01-01

    The Small Magellanic Cloud (SMC), Large Magellanic Cloud (LMC) and Irregular Galaxy IC 10 are valuable laboratories to study the physical, temporal and statistical properties of the X-ray pulsar population with multi-satellite observations, in order to probe fundamental physics. The known distance of these galaxies can help us easily categorize the luminosity of the pulsars and their age difference can be helpful for for studying the origin and evolution of compact objects. Therefore, a complete archive of 116 XMM-Newton PN, 151 Chandra (Advanced CCD Imaging Spectrometer) ACIS, and 952 RXTE PCA observations for the pulsars in the Small Magellanic Cloud (SMC) were collected and analyzed, along with 42 XMM-Newton and 30 Chandra observations for the Large Magellanic Cloud, spanning 1997-2014. From a sample of 67 SMC pulsars we generate a suite of products for each pulsar detection: spin period, flux, event list, high time-resolution light-curve, pulse-profile, periodogram, and X-ray spectrum. Combining all three satellites, I generated complete histories of the spin periods, pulse amplitudes, pulsed fractions and X-ray luminosities. Many of the pulsars show variations in pulse period due to the combination of orbital motion and accretion torques. Long-term spin-up/down trends are seen in 28/25 pulsars respectively, pointing to sustained transfer of mass and angular momentum to the neutron star on decadal timescales. The distributions of pulse detection and flux as functions of spin period provide interesting findings: mapping boundaries of accretion-driven X-ray luminosity, and showing that fast pulsars (P<10 s) are rarely detected, which yet are more prone to giant outbursts. In parallel we compare the observed pulse profiles to our general relativity (GR) model of X-ray emission in order to constrain the physical parameters of the pulsars.In addition, we conduct a search for optical counterparts to X-ray sources in the local dwarf galaxy IC 10 to form a comparison

  8. Shape of the nuclear magnetic resonance line in anisotropic superconductors with an irregular vortex lattice

    International Nuclear Information System (INIS)

    Minkin, A.V.; Tsarevskij, S.L.

    2006-01-01

    For high-temperature superconductors the shape of a NMR spectrum line is built regarding for variation of inhomogeneity of irregular vortex lattice magnetic field near superconductor surface. It is shown that the shape of a NMR line is not simply widened but noticeably varies depending on the degree of irregularity of a superconductor vortex lattice. This variation is associated with a local symmetry decrease in an irregular vortex lattice of the superconductor. Taking into account these circumstances may considerably change conclusions about the type of a vortex lattice and superconductor parameters which are commonly gained from NMR line shape analysis [ru

  9. Randomness control of vehicular motion through a sequence of traffic signals at irregular intervals

    International Nuclear Information System (INIS)

    Nagatani, Takashi

    2010-01-01

    We study the regularization of irregular motion of a vehicle moving through the sequence of traffic signals with a disordered configuration. Each traffic signal is controlled by both cycle time and phase shift. The cycle time is the same for all signals, while the phase shift varies from signal to signal by synchronizing with intervals between a signal and the next signal. The nonlinear dynamic model of the vehicular motion is presented by the stochastic nonlinear map. The vehicle exhibits the very complex behavior with varying both cycle time and strength of irregular intervals. The irregular motion induced by the disordered configuration is regularized by adjusting the phase shift within the regularization regions.

  10. Scintillations associated with bottomside sinusoidal irregularities in the equatorial F region

    Science.gov (United States)

    Basu, S.; Basu, S.; Valladares, C. E.; Dasgupta, A.; Whitney, H. E.

    1986-01-01

    Multisatellite scintillation observations and spaced receiver drift measurements are presented for a category of equatorial F region plasma irregularities characterized by nearly sinusoidal waveforms in the ion number density. The observations were made at Huancayo, Peru, and the measurements at Ancon, Peru, associated with irregularities observed by the Atmospheric-Explorer-E satellite on a few nights in December 1979. Utilizing ray paths to various geostationary satellites, it was found that the irregularities grow and decay almost simultaneously in long-lived patches extending at least 1000 km in the east-west direction.

  11. Target Tracking of a Linear Time Invariant System under Irregular Sampling

    Directory of Open Access Journals (Sweden)

    Jin Xue-Bo

    2012-11-01

    Full Text Available Due to event-triggered sampling in a system, or maybe with the aim of reducing data storage, tracking many applications will encounter irregular sampling time. By calculating the matrix exponential using an inverse Laplace transform, this paper transforms the irregular sampling tracking problem to the problem of tracking with time-varying parameters of a system. Using the common Kalman filter, the developed method is used to track a target for the simulated trajectory and video tracking. The results of simulation experiments have shown that it can obtain good estimation performance even at a very high irregular rate of measurement sampling time.

  12. An efficient algorithm for global periodic orbits generation near irregular-shaped asteroids

    Science.gov (United States)

    Shang, Haibin; Wu, Xiaoyu; Ren, Yuan; Shan, Jinjun

    2017-07-01

    Periodic orbits (POs) play an important role in understanding dynamical behaviors around natural celestial bodies. In this study, an efficient algorithm was presented to generate the global POs around irregular-shaped uniformly rotating asteroids. The algorithm was performed in three steps, namely global search, local refinement, and model continuation. First, a mascon model with a low number of particles and optimized mass distribution was constructed to remodel the exterior gravitational potential of the asteroid. Using this model, a multi-start differential evolution enhanced with a deflection strategy with strong global exploration and bypassing abilities was adopted. This algorithm can be regarded as a search engine to find multiple globally optimal regions in which potential POs were located. This was followed by applying a differential correction to locally refine global search solutions and generate the accurate POs in the mascon model in which an analytical Jacobian matrix was derived to improve convergence. Finally, the concept of numerical model continuation was introduced and used to convert the POs from the mascon model into a high-fidelity polyhedron model by sequentially correcting the initial states. The efficiency of the proposed algorithm was substantiated by computing the global POs around an elongated shoe-shaped asteroid 433 Eros. Various global POs with different topological structures in the configuration space were successfully located. Specifically, the proposed algorithm was generic and could be conveniently extended to explore periodic motions in other gravitational systems.

  13. Ionospheric Storm Effects and Equatorial Plasma Irregularities During the 17-18 March 2015 Event

    Science.gov (United States)

    Zhou, Yun-Liang; Luhr, Hermann; Xiong, Chao; Pfaff, Robert F.

    2016-01-01

    .This comprehensive view of ionospheric storm effects and plasma irregularities adds to our understanding of conditions that lead to ionospheric instabilities.

  14. Spelling pronunciation and visual preview both facilitate learning to spell irregular word

    NARCIS (Netherlands)

    Hilte, M.; Reitsma, P.

    2006-01-01

    Spelling pronunciations are hypothesized to be helpful in building up relatively stable phonologically underpinned orthographic representations, particularly for learning words with irregular phoneme-grapheme correspondences. In a four-week computer-based training, the efficacy of spelling

  15. On Impulsive Boundary Value Problems of Fractional Differential Equations with Irregular Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Guotao Wang

    2012-01-01

    Full Text Available We study nonlinear impulsive differential equations of fractional order with irregular boundary conditions. Some existence and uniqueness results are obtained by applying standard fixed-point theorems. For illustration of the results, some examples are discussed.

  16. Inter-hospital Cross-validation of Irregular Discharge Patterns for Young vs. Old Psychiatric Patients

    Science.gov (United States)

    Mozdzierz, Gerald J.; Davis, William E.

    1975-01-01

    Type of discharge (irregular vs. regular) and length of time hospitalized were used as unobtrusive measures of psychiatric patient acceptance of hospital treatment regime among two groups (18-27 years and 45 years and above) of patients. (Author)

  17. Irregular singularities in Liouville theory and Argyres-Douglas type gauge theories, I

    Energy Technology Data Exchange (ETDEWEB)

    Gaiotto, D. [Institute for Advanced Study (IAS), Princeton, NJ (United States); Teschner, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-03-15

    Motivated by problems arising in the study of N=2 supersymmetric gauge theories we introduce and study irregular singularities in two-dimensional conformal field theory, here Liouville theory. Irregular singularities are associated to representations of the Virasoro algebra in which a subset of the annihilation part of the algebra act diagonally. In this paper we define natural bases for the space of conformal blocks in the presence of irregular singularities, describe how to calculate their series expansions, and how such conformal blocks can be constructed by some delicate limiting procedure from ordinary conformal blocks. This leads us to a proposal for the structure functions appearing in the decomposition of physical correlation functions with irregular singularities into conformal blocks. Taken together, we get a precise prediction for the partition functions of some Argyres-Douglas type theories on S{sup 4}. (orig.)

  18. Conflict management among irregular immigrants: the micro politics of intercultural respect.

    OpenAIRE

    Clough, Paul; Works in Progress Seminars Series

    2010-01-01

    A talk in the Works in Progress Seminars Series with the title of "Conflict management among irregular immigrants: the micro politics of intercultural respect". This talk is given by Prof Paul Clough.

  19. Irregular singularities in Liouville theory and Argyres-Douglas type gauge theories, I

    International Nuclear Information System (INIS)

    Gaiotto, D.; Teschner, J.

    2012-03-01

    Motivated by problems arising in the study of N=2 supersymmetric gauge theories we introduce and study irregular singularities in two-dimensional conformal field theory, here Liouville theory. Irregular singularities are associated to representations of the Virasoro algebra in which a subset of the annihilation part of the algebra act diagonally. In this paper we define natural bases for the space of conformal blocks in the presence of irregular singularities, describe how to calculate their series expansions, and how such conformal blocks can be constructed by some delicate limiting procedure from ordinary conformal blocks. This leads us to a proposal for the structure functions appearing in the decomposition of physical correlation functions with irregular singularities into conformal blocks. Taken together, we get a precise prediction for the partition functions of some Argyres-Douglas type theories on S 4 . (orig.)

  20. Effect of surface stress and irregularity of the interface on the ...

    Indian Academy of Sciences (India)

    Surface stress; irregularity of the interface; magneto-elastic crustal ... stress plays a vital role in the propagation of waves due to the fact that the surface of a ...... Mumbai, for his computational help towards the numerical calculations and graphs.

  1. Dynamics of landslides on comets of irregular shape

    Science.gov (United States)

    Czechowski, Leszek

    2017-04-01

    Landslides were observed on a few comet's nuclei, e.g. [1], [2]. The mechanism of their origin is not obvious because of very low gravity. According to [2] fluidization and multiphase transport of cometary material could be an explanation. We investigate here motion of the mass on a comet of irregular shape. The mechanism responsible for the low friction is not considered here. In fact, mass motion often occurs without contact with the surface. The motion could be triggered by meteoroids impacts or by the tidal forces. Comets nuclei are believed to be built of soft materials like snow and dust. The landing of Philae on the comet 67P/Czuriumow-Gierasimienko indicates a different situation. According to [1]: "thermal probe did not fully penetrate the near-surface layers, suggesting a local resistance of the ground to penetration of >4 megapascals, equivalent to >2 megapascal uniaxial compressive strength". Here we assume that elastic properties of comet's nuclei could be similar to elastic properties of dry snow, namely Young modulus is assumed to be 1 - 100 MPa, see [3] and [4]. We consider nucleus of the shape of 67P/Churyumov-Gerasimenko with density 470 kg/m3. The impact or tidal forces result in changing of rotation of the comet. In general, the vector of angular velocity will be a subject to nutation that results in changing of centrifugal force, and consequently could be a factor triggering landslides. Note that nucleus' shape does not resemble the shape of surface of constant value of gravitational potential (i.e. 'geoid'). Our numerical models indicate the parts of the nucleus where landslides start and other parts where landslides stop. Of course, the regolith from the first type of regions would be removed to the regions of the second class. The motion of the mass is often complicated because of complicated distribution of the gravity and complicated shape of the nucleus. Acknowledgement: The research is partly supported by Polish National Science Centre

  2. Investigation on the relationship among sporadic Na, sporadic E, Field aligned irregularities and neutral winds

    Science.gov (United States)

    Sundararajan, Sridharan; Patra, Amit Kumar; Pant, Tarun; Gurubaran, Subramanian; Raghunath, Karnam

    In the Mesosphere and Lower Thermosphere region (80-100 km), metallic atoms, namely, sodium, potassium, lithium, Iron etc are formed due to ablation of meteors. The lidars based on resonance fluorescence principle has been used to study the vertical distribution of sodium atoms, because of their large abundance than other metals. The profiles of sodium density sometimes show enhancement by a factor of 2 than the normal layer in a narrow altitude region of 2 km and on these occasions, they are called sporadic sodium layer, or briefly Ns. On the other hand, there are observations on sporadic E and radar observations of Field Aligned Irregularities (FAI) associated with these sporadic E. Some investigations have been made to understand the relationship between sporadic E and FAI. Considering that sporadic E is composed of metallic ions and the time of metallic ions are larger compared to other ions, the sodium observations in the same height region would be of significant importance to understand the process involved. Despite a few past observations, no clear picture has emerged due to lack of simultaneous measurements of these parameters. The simultaneous observations of FAI echoes by the Indian MST radar and sodium concentration by the sodium lidar at Gadanki (13.5o N, 79.2o E) are being used to investigate the above mentioned relationship. The Sporadic E and neutral wind information are obtained from the ionosonde, meteor/MF radar observations from Trivandrum (8.5o N, 77E) and Tirunelveli (8.7o N, 77.8o E). The results obtained will be presented during the meeting.

  3. Efficient irregular wavefront propagation algorithms on Intel® Xeon Phi™

    OpenAIRE

    Gomes, Jeremias M.; Teodoro, George; de Melo, Alba; Kong, Jun; Kurc, Tahsin; Saltz, Joel H.

    2015-01-01

    We investigate the execution of the Irregular Wavefront Propagation Pattern (IWPP), a fundamental computing structure used in several image analysis operations, on the Intel® Xeon Phi™ co-processor. An efficient implementation of IWPP on the Xeon Phi is a challenging problem because of IWPP’s irregularity and the use of atomic instructions in the original IWPP algorithm to resolve race conditions. On the Xeon Phi, the use of SIMD and vectorization instructions is critical to attain high perfo...

  4. SUB-SAHARAN IRREGULAR MIGRANTS IN MOROCCO & THE EXCEPTIONAL REGULARISATION PROGRAMME IN 2014

    OpenAIRE

    Naama, Mbarek

    2017-01-01

    Naama, Mbarek. Sub-Saharan Irregular Migrants in Morocco and the Exceptional Regularisation Programme in 2014. Diak South Helsinki Finland. Spring 2017. 43 Pages. Language: English. Diaconia University of Applied Sciences, Degree Programme in Social Services, Option in Community Development, Bachelor of Social Services (UAS). After decades of ignoring irregular migration and refusing to acknowledge that Morocco is no longer just a transit but also a host country for increasing complex mig...

  5. Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

    OpenAIRE

    Carlos Gustavo V. De Moraes; Tiago S. Prata; Jeffrey Liebmann; Robert Ritch

    2008-01-01

    Recent advances in tonometry have led to the development of a number of devices with differing clinical applications. Their role in cases of abnormal corneal thickness and surface irregularities is particularly important, as inaccurate estimation of the true intraocular pressure (IOP) in such cases may lead to suboptimal evaluation. The purpose of the present review was to evaluate the accuracy of the most widely used devices in cases of corneal thickness and surface irregularities, based ...

  6. Formation of dwarf ellipticals and dwarf irregular galaxies by interaction of giant galaxies under environmental influence

    OpenAIRE

    Chattopadhyay, Tanuka; Debsarma, Suma; Karmakar, Pradip; Davoust, Emmanuel

    2014-01-01

    A model is proposed for the formation of gas-rich dwarf irregular galaxies and gas-poor, rotating dwarf elliptical galaxies following the interaction between two giant galaxies as a function of space density. The formation of dwarf galaxies is considered to depend on a random variable, the tidal index theta, an environmental parameter defined by Karachentsev et al. (2004), such that for theta less than zero, the formation of dwarf irregular galaxy is assured whereas for theta greater than zer...

  7. A Generalized FDM for solving the Poisson's Equation on 3D Irregular Domains

    Directory of Open Access Journals (Sweden)

    J. Izadian

    2014-01-01

    Full Text Available In this paper a new method for solving the Poisson's equation with Dirichlet conditions on irregular domains is presented. For this purpose a generalized finite differences method is applied for numerical differentiation on irregular meshes. Three examples on cylindrical and spherical domains are considered. The numerical results are compared with analytical solution. These results show the performance and efficiency of the proposed method.

  8. Characterizing neural activities evoked by manual acupuncture through spiking irregularity measures

    International Nuclear Information System (INIS)

    Xue Ming; Wang Jiang; Deng Bin; Wei Xi-Le; Yu Hai-Tao; Chen Ying-Yuan

    2013-01-01

    The neural system characterizes information in external stimulations by different spiking patterns. In order to examine how neural spiking patterns are related to acupuncture manipulations, experiments are designed in such a way that different types of manual acupuncture (MA) manipulations are taken at the ‘Zusanli’ point of experimental rats, and the induced electrical signals in the spinal dorsal root ganglion are detected and recorded. The interspike interval (ISI) statistical histogram is fitted by the gamma distribution, which has two parameters: one is the time-dependent firing rate and the other is a shape parameter characterizing the spiking irregularities. The shape parameter is the measure of spiking irregularities and can be used to identify the type of MA manipulations. The coefficient of variation is mostly used to measure the spike time irregularity, but it overestimates the irregularity in the case of pronounced firing rate changes. However, experiments show that each acupuncture manipulation will lead to changes in the firing rate. So we combine four relatively rate-independent measures to study the irregularity of spike trains evoked by different types of MA manipulations. Results suggest that the MA manipulations possess unique spiking statistics and characteristics and can be distinguished according to the spiking irregularity measures. These studies have offered new insights into the coding processes and information transfer of acupuncture. (interdisciplinary physics and related areas of science and technology)

  9. Effects of surface irregularities on intensity data from laser scanning: an experimental approach.

    Directory of Open Access Journals (Sweden)

    G. Teza

    2008-06-01

    Full Text Available The results of an experiment carried out with the aim to investigate the role of surface irregularities on the intensity data provided by a terrestrial laser scanner (TLS survey are reported here. Depending on surface roughness, the interaction between an electromagnetic wave and microscopic irregularities leads to a Lambertian-like diffusive light reflection, allowing the TLS to receive the backscattered component of the signal. The described experiment consists in a series of TLS-based acquisitions of a rotating artificial target specifically conceived in order to highlight the effects on the intensity data due to surface irregularity. This target is articulated in a flat plate and in an irregular surface, whose macro-roughness has a characteristic length with the same order of the spot size. Results point out the different behavior of the plates. The intensity of the signal backscattered by the planar element decreases if the incidence angle increases, whereas the intensity of the signal backscattered by the irregular surface is almost constant if the incidence angle varies. Since the typical surfaces acquired in a geological/geophysical survey are generally irregular, these results imply that the intensity data can be easily used in order to evaluate the reflectance of the material at the considered wavelength, e.g. for pattern recognition purposes.

  10. Study of electromagnetic wave scattering by periodic density irregularities in plasma

    International Nuclear Information System (INIS)

    Lyle, R.; Kuo, S.P.; Huang, J.

    1995-01-01

    A quasi-particle approach is used to formulate wave propagation and scattering in a periodically structured plasma. The theory is then applied to study the effect of bottomside sinusoidal (BSS) irregularities on the propagation of beacon satellites signals through the ionosphere. In this approach, the radio wave is treated as a distribution of quasi-particles described by a Wigner distribution function governed by a transport equation. The irregularities providing the collisional effect are modeled as a two dimensional density modulation on a uniform background plasma. The present work generalizes the previous work by including the spectral bandwidth (Δk/k) effect of the spatially periodic irregularities on the transionospheric signal propagation. The collision of quasi-particles with the irregularities modifies the quasi-particle distribution and give rise to the wave scattering phenomenon. The multiple scattering process is generally considered in this deterministic analysis of radio wave scattering off the ionospheric density irregularities. The analysis shows that this two dimensional density grating effectively modulates the intensity of the beacon satellite signals. This spatial modulation of the wave intensity is converted into time modulation due to the drift of the ionospheric irregularities, which then results in the scintillation of the beacon satellite signals

  11. New prospective 4D-CT for mitigating the effects of irregular respiratory motion

    Science.gov (United States)

    Pan, Tinsu; Martin, Rachael M.; Luo, Dershan

    2017-08-01

    Artifact caused by irregular respiration is a major source of error in 4D-CT imaging. We propose a new prospective 4D-CT to mitigate this source of error without new hardware, software or off-line data-processing on the GE CT scanner. We utilize the cine CT scan in the design of the new prospective 4D-CT. The cine CT scan at each position can be stopped by the operator when an irregular respiration occurs, and resumed when the respiration becomes regular. This process can be repeated at one or multiple scan positions. After the scan, a retrospective reconstruction is initiated on the CT console to reconstruct only the images corresponding to the regular respiratory cycles. The end result is a 4D-CT free of irregular respiration. To prove feasibility, we conducted a phantom and six patient studies. The artifacts associated with the irregular respiratory cycles could be removed from both the phantom and patient studies. A new prospective 4D-CT scanning and processing technique to mitigate the impact of irregular respiration in 4D-CT has been demonstrated. This technique can save radiation dose because the repeat scans are only at the scan positions where an irregular respiration occurs. Current practice is to repeat the scans at all positions. There is no cost to apply this technique because it is applicable on the GE CT scanner without new hardware, software or off-line data-processing.

  12. Influence of long-wavelength track irregularities on the motion of a high-speed train

    Science.gov (United States)

    Hung, C. F.; Hsu, W. L.

    2018-01-01

    Vertical track irregularities over viaducts in high-speed rail systems could be possibly caused by concrete creep if pre-stressed concrete bridges are used. For bridge spans that are almost uniformly distributed, track irregularity exhibits a near-regular wave profile that excites car bodies as a high-speed train moves over the bridge system. A long-wavelength irregularity induces low-frequency excitation that may be close to the natural frequencies of the train suspension system, thereby causing significant vibration of the car body. This paper investigates the relationship between the levels of car vibration, bridge vibration, track irregularity, and the train speed. First, this study investigates the vibration levels of a high-speed train and bridge system using 3D finite-element (FE) transient dynamic analysis, before and after adjustment of vertical track irregularities by means of installing shimming plates under rail pads. The analysis models are validated by in situ measurements and on-board measurement. Parametric studies of car body vibration and bridge vibration under three different levels of track irregularity at five train speeds and over two bridge span lengths are conducted using the FE model. Finally, a discontinuous shimming pattern is proposed to avoid vehicle suspension resonance.

  13. Properties of the Irregular Satellite System around Uranus Inferred from K2 , Herschel , and Spitzer Observations

    Energy Technology Data Exchange (ETDEWEB)

    Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Szakáts, R.; Kiss, L. L. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklós út 15-17, H-1121 Budapest (Hungary); Mommert, M. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Müller, T., E-mail: farkas.aniko@csfk.mta.hu [Max-Plank-Institut für extraterrestrsiche Pyhsik, Garching (Germany)

    2017-09-01

    In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel /PACS and Spitzer /MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

  14. Properties of the Irregular Satellite System around Uranus Inferred from K2, Herschel, and Spitzer Observations

    Science.gov (United States)

    Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Mommert, M.; Szakáts, R.; Müller, T.; Kiss, L. L.

    2017-09-01

    In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel/PACS and Spitzer/MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

  15. Modification of transmission dose algorithm for irregularly shaped radiation field and tissue deficit

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Hyong Geon; Shin, Kyo Chul [Dankook Univ., College of Medicine, Seoul (Korea, Republic of); Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan [Seoul National Univ., College of Medicine, Seoul (Korea, Republic of); Lee, Hyoung Koo [The Catholic Univ., College of Medicine, Seoul (Korea, Republic of)

    2002-07-01

    Algorithm for estimation of transmission dose was modified for use in partially blocked radiation fields and in cases with tissue deficit. The beam data was measured with flat solid phantom in various conditions of beam block. And an algorithm for correction of transmission dose in cases of partially blocked radiation field was developed from the measured data. The algorithm was tested in some clinical settings with irregular shaped field. Also, another algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. This algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients by using multiple sheets of solid phantoms. The algorithm for correction of beam block could accurately reflect the effect of beam block, with error within {+-}1.0%, both with square fields and irregularly shaped fields. The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within {+-}1.0% in most situations and within {+-}3.0% in experimental settings with irregular contours mimicking breast cancer treatment set-up. Developed algorithms could accurately estimate the transmission dose in most radiation treatment settings including irregularly shaped field and irregularly shaped body contour with tissue deficit in transmission dosimetry.

  16. Modification of transmission dose algorithm for irregularly shaped radiation field and tissue deficit

    International Nuclear Information System (INIS)

    Yun, Hyong Geon; Shin, Kyo Chul; Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan; Lee, Hyoung Koo

    2002-01-01

    Algorithm for estimation of transmission dose was modified for use in partially blocked radiation fields and in cases with tissue deficit. The beam data was measured with flat solid phantom in various conditions of beam block. And an algorithm for correction of transmission dose in cases of partially blocked radiation field was developed from the measured data. The algorithm was tested in some clinical settings with irregular shaped field. Also, another algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. This algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients by using multiple sheets of solid phantoms. The algorithm for correction of beam block could accurately reflect the effect of beam block, with error within ±1.0%, both with square fields and irregularly shaped fields. The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within ±1.0% in most situations and within ±3.0% in experimental settings with irregular contours mimicking breast cancer treatment set-up. Developed algorithms could accurately estimate the transmission dose in most radiation treatment settings including irregularly shaped field and irregularly shaped body contour with tissue deficit in transmission dosimetry

  17. Irregular menses predicts ovarian cancer: Prospective evidence from the Child Health and Development Studies.

    Science.gov (United States)

    Cirillo, Piera M; Wang, Erica T; Cedars, Marcelle I; Chen, Lee-May; Cohn, Barbara A

    2016-09-01

    We tested the hypothesis that irregular menstruation predicts lower risk for ovarian cancer, possibly due to less frequent ovulation. We conducted a 50-year prospective study of 15,528 mothers in the Child Health and Development Studies cohort recruited from the Kaiser Foundation Health Plan from 1959 to 1966. Irregular menstruation was classified via medical record and self-report at age 26. We identified 116 cases and 84 deaths due to ovarian cancer through 2011 via linkage to the California Cancer Registry and Vital Statistics. Contrary to expectation, women with irregular menstrual cycles had a higher risk of ovarian cancer incidence and mortality over the 50-year follow-up. Associations increased with age (p irregular menstruation and ovarian cancer-we unexpectedly found higher risk for women with irregular cycles. These women are easy to identify and many may have polycystic ovarian syndrome. Classifying high-risk phenotypes such as irregular menstruation creates opportunities to find novel early biomarkers, refine clinical screening protocols and potentially develop new risk reduction strategies. These efforts can lead to earlier detection and better survival for ovarian cancer. © 2016 UICC.

  18. Irregular water supply, household usage and dengue: a bio-social study in the Brazilian Northeast Abastecimento irregular de água, seu uso domiciliar e dengue: uma pesquisa biossocial no Nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    Andrea Caprara

    2009-01-01

    Full Text Available Despite increased vector control efforts, dengue fever remains endemic in Fortaleza, Northeast Brazil, where sporadic epidemic outbreaks have occurred since 1986. Multiple factors affect vector ecology such as social policy, migration, urbanization, city water supply, garbage disposal and housing conditions, as well as community level understanding of the disease and related practices. This descriptive study used a multi-disciplinary approach that bridged anthropology and entomology. A multiple case study design was adopted to include research in six study areas, defined as blocks. The water supply is irregular in households from both under-privileged and privileged areas, however, clear differences exist. In the more privileged blocks, several homes are not connected to the public water system, but have a well and pump system and therefore irregularity of supply does not affect them. In households from under-privileged blocks, where the water supply is irregular, the frequent use of water containers such as water tanks, cisterns, barrels and pots, creates environmental conditions with a greater number of breeding areas. In under-privileged homes, there are more possible breeding areas and environmental conditions that may improve the chances of Aedes aegypti survival.Apesar do crescimento de esforços no controle, desde 1986, a dengue, em Fortaleza, Nordeste do Brasil, continua endêmica com esporádicos surtos epidêmicos. Diversos fatores influenciam a ecologia do vetor, como as políticas sociais, a migração, a urbanização, o abastecimento urbano de água, a coleta de resíduos sólidos, as condições das casas, assim como as interpretações e práticas da comunidade. Este estudo descritivo utiliza uma abordagem multidisciplinar conjugando a antropologia e a entomologia. Foi adotado um desenho de estudo de caso múltiplo em seis quarteirões da cidade. O abastecimento de água é irregular seja nas casas pobres, seja naquelas

  19. Displacement and stress fields around rock fractures opened by irregular overpressure variations

    Directory of Open Access Journals (Sweden)

    Shigekazu eKusumoto

    2014-05-01

    Full Text Available Many rock fractures are entirely driven open by fluids such as ground water, geothermal water, gas, oil, and magma. These are a subset of extension fractures (mode I cracks; e.g., dikes, mineral veins and joints referred to as hydrofractures. Field measurements show that many hydrofractures have great variations in aperture. However, most analytical solutions for fracture displacement and stress fields assume the loading to be either constant or with a linear variation. While these solutions have been widely used, it is clear that a fracture hosted by heterogeneous and anisotropic rock is normally subject to loading that is neither constant nor with a linear variation. Here we present new general solutions for the displacement and stress fields around hydrofractures, modelled as two-dimensional elastic cracks, opened by irregular overpressure variations given by the Fourier cosine series. Each solution has two terms. The first term gives the displacement and stress fields due to the average overpressure acting inside the crack; it is given by the initial term of the Fourier coefficients expressing the overpressure variation. The second term gives the displacement and stress fields caused by the overpressure variation; it is given by general terms of the Fourier coefficients and solved through numerical integration. Our numerical examples show that the crack aperture variation closely reflects the overpressure variation. Also, that the general displacement and stress fields close to the crack follow the overpressure variation but tend to be more uniform far from the crack. The present solutions can be used to estimate the displacement and stress fields around any fluid-driven crack, that is, any hydrofracture, as well as its aperture, provided the variation in overpressure can be described by Fourier series. The solutions add to our understanding of local stresses, displacements, and fluid transport associated with hydrofractures in the crust.

  20. Dose calculations for irregular fields using three-dimensional first-scatter integration

    International Nuclear Information System (INIS)

    Boesecke, R.; Scharfenberg, H.; Schlegel, W.; Hartmann, G.H.

    1986-01-01

    This paper describes a method of dose calculations for irregular fields which requires only the mean energy of the incident photons, the geometrical properties of the irregular field and of the therapy unit, and the attenuation coefficient of tissue. The method goes back to an approach including spatial aspects of photon scattering for inhomogeneities for the calculation of dose reduction factors as proposed by Sontag and Cunningham (1978). It is based on the separation of dose into a primary component and a scattered component. The scattered component can generally be calculated for each field by integration over dose contributions from scattering in neighbouring volume elements. The quotient of this scattering contribution in the irregular field and the scattering contribution in the equivalent open field is then the correction factor for scattering in an irregular field. A correction factor for the primary component can be calculated if the attenuation of the photons in the shielding block is properly taken into account. The correction factor is simply given by the quotient of primary photons of the irregular field and the primary photons of the open field. (author)

  1. Observations of inner plasmasphere irregularities with a satellite-beacon radio-interferometer array

    International Nuclear Information System (INIS)

    Jacobson, A.R.; Hoogeveen, G.; Carlos, R.C.; Wu, G.; Fejer, B.G.; Kelley, M.C.

    1996-01-01

    A radio-interferometer array illuminated by 136-MHz beacons of several geosynchronous satellites has been used to study small (≥10 13 m -2 ) transient disturbances in the total electron content along the lines of sight to the satellites. High-frequency (f>3 mHz) electron content oscillations are persistently observed, particularly during night and particularly during geomagnetically disturbed periods. The oscillations move across the array plane at speeds in the range 200 endash 2000 m/s, with propagation azimuths that are strongly peaked in lobes toward the western half-plane. Detailed analysis of this azimuth behavior, involving comparison between observations on various satellite positions, indicates compellingly that the phase oscillations originate in radio refraction due to geomagnetically aligned plasma density perturbations in the inner plasmasphere. The motion of the phase perturbations across the array plane is caused by EXB drift of the plasma medium in which the irregularities are embedded. We review the statistics of 2.5 years of around-the-clock data on the local time, magnetic disturbance, seasonal, and line-of-sight variations of these observed irregularities. We compare the irregularities close-quote inferred electrodynamic drifts to what is known about midlatitude plasma drift from incoherent scatter. Finally, we show in detail how the observation of these irregularities provides a unique and complementary monitor of inner plasmasphere irregularity incidence and zonal drift.copyright 1996 American Geophysical Union

  2. Method of determining effects of heat-induced irregular refractive index on an optical system.

    Science.gov (United States)

    Song, Xifa; Li, Lin; Huang, Yifan

    2015-09-01

    The effects of an irregular refractive index on optical performance are examined. A method was developed to express a lens's irregular refractive index distribution. An optical system and its mountings were modeled by a thermomechanical finite element (FE) program in the predicted operating temperature range, -45°C-50°C. FE outputs were elaborated using a MATLAB optimization routine; a nonlinear least squares algorithm was adopted to determine which gradient equation best fit each lens's refractive index distribution. The obtained gradient data were imported into Zemax for sequential ray-tracing analysis. The root mean square spot diameter, modulation transfer function, and diffraction ensquared energy were computed for an optical system under an irregular refractive index and under thermoelastic deformation. These properties are greatly reduced by the irregular refractive index effect, which is one-third to five-sevenths the size of the thermoelastic deformation effect. Thus, thermal analyses of optical systems should consider not only thermoelastic deformation but also refractive index irregularities caused by inhomogeneous temperature.

  3. The nature and source of irregular discharges to stormwater entering Sydney estuary, Australia

    International Nuclear Information System (INIS)

    Beck, H.J.; Birch, G.F.

    2014-01-01

    Irregular discharges of polluted stormwater into drainage systems during base flow (no rainfall) result in acute ecological impacts within fluvial and estuarine environments. In this study, metal and TSS concentrations were significantly more variable during business hours of weekdays (i.e. high-business activity) than weekends/public holidays (i.e. low-business activity) within three highly-urbanised catchments of Sydney estuary (Australia), as determined by analysing multivariate dispersion (PERMDISP). Concentrations of TSS and all metals analysed (Al, Ca, Cu, Fe, Mg, Pb and Zn) were also significantly greater during high- than low-business periods within at least one of the three catchments. In no case were concentrations significantly higher during low- than high-business periods. This pattern of contamination supports the hypothesis that commercial and industrial sources are major contributors of irregular discharges of contamination to Sydney estuary. Irregular discharges and consequential ecological impacts may be effectively reduced in this environment by focussing management efforts on these activities. - Highlights: • Irregular discharges of pollution have acute impacts on aquatic ecosystems. • These discharges were thought to be made during low activity periods, such as night. • Pollution was more concentrated and erratic during high- than low-business periods. • Timing of pollution suggests commercial and industrial activities are major sources. • Discharges effectively reduced by managing commercial and industrial activities. - Previously unreported irregular, illegal discharges of polluted stormwater released to estuaries result in acute ecological impacts and are potentially related to commercial/industrial activities

  4. 30 MHz radar observations of artificial E region field-aligned plasma irregularities

    Directory of Open Access Journals (Sweden)

    D. L. Hysell

    2008-02-01

    Full Text Available Artificial E region field aligned irregularities (FAIs have been observed during heating experiments at the HAARP facility using a new 30 MHz coherent scatter radar imager deployed near Homer, Alaska. Irregularities were observed during brief experiments on three quiet days in July and August, 2007, when the daytime E region critical frequency was close to 3 MHz. Irregularities were consistently generated and detected during experiments with O-mode HF pumping on zenith with a 1-min on, 1-min off CW modulation. The scattering cross sections, rise, and fall times of the echoes were observed as well as their spectral properties. Results were found to be mainly in agreement with observations from other mid- and high-latitude sites with some discrepancies. Radar images of the irregularity-filled volume on one case exhibited clear variations in backscatter power and Doppler shift across the volume. The images furthermore show the emergence of a small irregularity-filled region to the south southwest of the main region in the approximate direction of magnetic zenith.

  5. Using forbidden ordinal patterns to detect determinism in irregularly sampled time series.

    Science.gov (United States)

    Kulp, C W; Chobot, J M; Niskala, B J; Needhammer, C J

    2016-02-01

    It is known that when symbolizing a time series into ordinal patterns using the Bandt-Pompe (BP) methodology, there will be ordinal patterns called forbidden patterns that do not occur in a deterministic series. The existence of forbidden patterns can be used to identify deterministic dynamics. In this paper, the ability to use forbidden patterns to detect determinism in irregularly sampled time series is tested on data generated from a continuous model system. The study is done in three parts. First, the effects of sampling time on the number of forbidden patterns are studied on regularly sampled time series. The next two parts focus on two types of irregular-sampling, missing data and timing jitter. It is shown that forbidden patterns can be used to detect determinism in irregularly sampled time series for low degrees of sampling irregularity (as defined in the paper). In addition, comments are made about the appropriateness of using the BP methodology to symbolize irregularly sampled time series.

  6. On the total irregularity strength of caterpillar with each internal vertex has degree three

    Science.gov (United States)

    Indriati, Diari; Rosyida, Isnaini; Widodo

    2018-04-01

    Let G be a simple, connected and undirected graph with vertex set V and edge set E. A total k-labeling f:V \\cup E\\to \\{1,2,\\ldots,k\\} is defined as totally irregular total k-labeling if the weights of any two different both vertices and edges are distinct. The weight of vertex x is defined as wt(x)=f(x)+{\\sum }xy\\in Ef(xy), while the weight of edge xy is wt(xy)=f(x)+f(xy)+f(y). A minimum k for which G has totally irregular total k-labeling is mentioned as total irregularity strength of G and denoted by ts(G). This paper contains investigation of totally irregular total k-labeling and determination of their total irregularity strengths for caterpillar graphs with each internal vertex between two stars has degree three. The results are ts({S}n,3,n)=\\lceil \\frac{2n}{2}\\rceil, ts({S}n,3,3,n)=\\lceil \\frac{2n+1}{2}\\rceil and ts({S}n,3,3,3,n)=\\lceil \\frac{2n+2}{2}\\rceil for n > 4:

  7. Simulating Seismic Wave Propagation in Viscoelastic Media with an Irregular Free Surface

    Science.gov (United States)

    Liu, Xiaobo; Chen, Jingyi; Zhao, Zhencong; Lan, Haiqiang; Liu, Fuping

    2018-05-01

    In seismic numerical simulations of wave propagation, it is very important for us to consider surface topography and attenuation, which both have large effects (e.g., wave diffractions, conversion, amplitude/phase change) on seismic imaging and inversion. An irregular free surface provides significant information for interpreting the characteristics of seismic wave propagation in areas with rugged or rapidly varying topography, and viscoelastic media are a better representation of the earth's properties than acoustic/elastic media. In this study, we develop an approach for seismic wavefield simulation in 2D viscoelastic isotropic media with an irregular free surface. Based on the boundary-conforming grid method, the 2D time-domain second-order viscoelastic isotropic equations and irregular free surface boundary conditions are transferred from a Cartesian coordinate system to a curvilinear coordinate system. Finite difference operators with second-order accuracy are applied to discretize the viscoelastic wave equations and the irregular free surface in the curvilinear coordinate system. In addition, we select the convolutional perfectly matched layer boundary condition in order to effectively suppress artificial reflections from the edges of the model. The snapshot and seismogram results from numerical tests show that our algorithm successfully simulates seismic wavefields (e.g., P-wave, Rayleigh wave and converted waves) in viscoelastic isotropic media with an irregular free surface.

  8. Morning Cortisol Levels and Perceived Stress in Irregular Shift Workers Compared with Regular Daytime Workers

    Directory of Open Access Journals (Sweden)

    Harri Lindholm

    2012-01-01

    Full Text Available The 24/7 work environment and irregular shifts may markedly enhance the psychological pressure of media work. Changes in the hypothalamic-pituitary-adrenal axis reflect adaptation to stress. We analysed the correlation between subjective stress, sleep, salivary cortisol, and melatonin hormones among Finnish media workers with regular daytime work (RDW and with irregular shift work (ISW while controlling confounders. From 874 employees with regular daytime work or with irregular shift work, 70 employees from both groups were randomly selected. The final number of employees with a complete salivary cortisol profile was 66 in the RDW group and 65 in the ISW group. Five saliva samples were gathered from each subject before and during a working day. The salivary cortisol level of the sample taken 60 minutes after awakening (T1 was compared to the salivary cortisol level taken immediately after awakening (T0, T1/T0 ratio. The ratio was higher in the ISW group than in RDW group. Irregular shift work (P<0.001, severe stress (P<0.05, and less sleep (P<0.05 were independently associated with an augmented cortisol response after awakening. A stressful work environment and irregular shift work enhance cortisol excretion after waking. In the long run, this may become detrimental to health.

  9. Application of the pothole DAF method to vehicles traversing periodic roadway irregularities

    Science.gov (United States)

    Pesterev, A. V.; Bergman, L. A.; Tan, C. A.; Yang, B.

    2005-01-01

    This paper is a sequel to the work discussed in Pesterev et al. (Journal of Sound and Vibration, in press). In that paper, it was suggested that the technique to determine the effect of a local road surface irregularity on the dynamics of a vehicle modelled as a linear multi-degree-of-freedom system relies on the so-called pothole dynamic amplification factor (DAF), which is a complex-valued function specific to the irregularity shape. This paper discusses the companion problem of how to determine the DAF function for an irregularity represented as a superposition of simpler ones. Another purpose of this paper is to demonstrate the application of the pothole DAF functions technique to finding a priori estimates of the effect of irregularities with a repeated structure. Specifically, we solve the problem of finding the conditions under which the dynamic effect of two identical potholes located one after another is greater than that due to the single pothole. We also find the estimate for the number of periods of a periodic irregularity that are sufficient in order to consider the oscillator response as steady state. The discussions are illustrated by numerical examples.

  10. Prices and costs of irregularity in renewable resources in the liberalized electricity markets

    International Nuclear Information System (INIS)

    Menanteau, Ph.; Finon, D.

    2004-01-01

    The problems raised by incorporating irregular production are of a technical nature (risk of non-availability during peak demand, the requirements for additional reserves) but the electricity markets methods of operation impose economic penalties, which greatly exceed these additional technical costs. In this document, the authors examine the nature of the technical problems posed by irregularity of production and the additional costs resulting from this, and then analyse the origins of the economic penalties that the operation of liberalized electricity markets impose, taking in particular the example of the British market, the New Energy Trading Arrangement (NETA). It would appear that the markets' operating rules may conflict, in certain cases, with the targets for promoting electricity generation from renewable resources. Two types of solutions can therefore be envisaged: a set of rules to limit the impact on irregular production or collective handling of the adjustment to production from renewable resources as already exists in the Nordic electricity markets. (authors)

  11. Working irregular shift patterns is associated with functional constipation among healthy trainee nurses

    Directory of Open Access Journals (Sweden)

    Ali Ebrahim

    2017-11-01

    Full Text Available The circadian system has a role in regulating gastrointestinal physiology. Perturbation of this system is associated with gastrointestinal tract dysfunction. Shiftwork and poor sleep quality are associated with functional gastrointestinal disorders among many professional groups. This study compared bowel habits between trainee nurses with regular and irregular patterns of shiftwork. Male and female nursing students, enrolled on the first year (regular shifts; n=49 and the fourth year (irregular shifts, n=48 of a nursing degree course were surveyed. Questionnaires were used to assess functional diarrhea and constipation over a three month period. The prevalence of functional constipation among regular shift workers was lower than that found among irregular shift workers; 31.3% and 61.2%, respectively. There was no difference between the two groups in relation to the prevalence of diarrhea. This suggests an association between shiftwork and functional constipation, but not with functional diarrhea.

  12. Spiking irregularity and frequency modulate the behavioral report of single-neuron stimulation.

    Science.gov (United States)

    Doron, Guy; von Heimendahl, Moritz; Schlattmann, Peter; Houweling, Arthur R; Brecht, Michael

    2014-02-05

    The action potential activity of single cortical neurons can evoke measurable sensory effects, but it is not known how spiking parameters and neuronal subtypes affect the evoked sensations. Here, we examined the effects of spike train irregularity, spike frequency, and spike number on the detectability of single-neuron stimulation in rat somatosensory cortex. For regular-spiking, putative excitatory neurons, detectability increased with spike train irregularity and decreasing spike frequencies but was not affected by spike number. Stimulation of single, fast-spiking, putative inhibitory neurons led to a larger sensory effect compared to regular-spiking neurons, and the effect size depended only on spike irregularity. An ideal-observer analysis suggests that, under our experimental conditions, rats were using integration windows of a few hundred milliseconds or more. Our data imply that the behaving animal is sensitive to single neurons' spikes and even to their temporal patterning. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. VHF and UHF radar observations of equatorial F region ionospheric irregularities and background densities

    Science.gov (United States)

    Towle, D. M.

    1980-02-01

    A series of measurements of the properties of equatorial ionospheric irregularities were made at Kwajalein, Marshall Islands (M.I.) in August 1977 and July-August 1978. These measurements, sponsored by the Defense Nuclear Agency (DNA), involved coordinated ground-based and in situ sensors. The ARPA Long-Range Tracking and Instrumentation Radar (ALTAIR), operated by Lincoln Laboratory, obtained backscatter and transmission data during five nights in August 1977 and eight nights in July-August 1978. This report describes the ALTAIR data from the night of August 11, 1978, which yield direct quantitative measurements of 1-m and 3/8-m irregularities and of plasma depleted regions. These plasma depleted regions, previously predicted on the basis of theoretical analysis and in situ data, were observed during the decay phase and not the generative phase of the field-aligned irregularities.

  14. Application of Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS) for the investigation of midlatitude ionospheric irregularities

    Science.gov (United States)

    Wang, Jin; Zhou, Xiaoming; Qiao, Lei; Gong, Wanlin

    2018-03-01

    An upgrade of Wuhan Ionospheric Backscattering Sounding System (WIOBSS) was developed in 2015. Based on the Universal Serial Bus (USB), and a high performance FPGA, the newly designed WIOBSS has a completely digital structure, which makes it portable and flexible. Two identical WIOBSSs, which were situated at Mile (24.31°N, 103.39°E) and Puer (22.74°N, 101.05°E) respectively, were used to investigate the ionospheric irregularities. The comparisons of group distance, Doppler shift and width between Mile-Puer and Puer-Mile VHF ionospheric propagation paths indicate that the reciprocity of the irregularities is satisfied at midlatitude region. The WIOBSS is robust in the detection of ionospheric irregularities.

  15. Institutional Root Cause of the Irregularity of Social Security Funds in China

    Institute of Scientific and Technical Information of China (English)

    Bingwen Zheng

    2007-01-01

    This paper analyzes institutional defects in the Chinese social security system, based on irregularities in social security funds revealed in the Audit Report by the China National Audit Office. The author divides the irregularities into five categories according to the nature of fund use. The results show that the institutional root cause of the irregularities lies in the unreasonable design and operation of the social security system, which currently faces management and institutional risks. This paper argues that simple rhetoric about strengthening regulation and supervision cannot help to reduce illegal practices, or to realize risk control. The only solution is to reform the social security system. Specifically, the Chinese Government should regulate the administrative cost of the social security system,and the behavior of its agencies, through legislation, reform the investment regime to increase rate of return of pension assets, and adjust and reshape the existing social security system, so as to elevate its pooling level.

  16. On the areas of various bodies in the Euclidean space: The case of irregular convex polygons

    International Nuclear Information System (INIS)

    Ozoemena, P.C.

    1988-11-01

    A theorem is proposed for the areas of n-sided irregular convex polygons, of given length of sides. The theorem is illustrated as a simple but powerful one in estimating the areas of irregular polygons, being dependent only on the number of sides n (and not on any of the explicit angles) of the irregular polygon. Finally, because of the global symmetry shown by equilateral triangles, squares and circles under group (gauge) theory, the relationships governing their areas, when they are inscribed or escribed in one another are discussed as riders, and some areas of their applications in graph theory, ratios and maxima and minima problems of differential calculus briefly mentioned. (author). 11 refs, 6 figs, 1 tab

  17. Ebola virus infection induces irregular dendritic cell gene expression.

    Science.gov (United States)

    Melanson, Vanessa R; Kalina, Warren V; Williams, Priscilla

    2015-02-01

    Filoviruses subvert the human immune system in part by infecting and replicating in dendritic cells (DCs). Using gene arrays, a phenotypic profile of filovirus infection in human monocyte-derived DCs was assessed. Monocytes from human donors were cultured in GM-CSF and IL-4 and were infected with Ebola virus Kikwit variant for up to 48 h. Extracted DC RNA was analyzed on SuperArray's Dendritic and Antigen Presenting Cell Oligo GEArray and compared to uninfected controls. Infected DCs exhibited increased expression of cytokine, chemokine, antiviral, and anti-apoptotic genes not seen in uninfected controls. Significant increases of intracellular antiviral and MHC I and II genes were also noted in EBOV-infected DCs. However, infected DCs failed to show any significant difference in co-stimulatory T-cell gene expression from uninfected DCs. Moreover, several chemokine genes were activated, but there was sparse expression of chemokine receptors that enabled activated DCs to home to lymph nodes. Overall, statistically significant expression of several intracellular antiviral genes was noted, which may limit viral load but fails to stop replication. EBOV gene expression profiling is of vital importance in understanding pathogenesis and devising novel therapeutic treatments such as small-molecule inhibitors.

  18. Some new features of electron density irregularities over SHAR during strong spread F

    Directory of Open Access Journals (Sweden)

    S. Raizada

    Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip latitude 5.5°N to study electron density and electric field irregularities during spread F. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of electron density fluctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150-300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165-178 km, in the intermediate scale size range, observed during this flight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200-330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms-1. These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.

    Key words: Ionosphere (equatorial ionosphere; ionospheric irregularities - Radio science (ionospheric physics

  19. Some new features of electron density irregularities over SHAR during strong spread F

    Directory of Open Access Journals (Sweden)

    S. Raizada

    2000-02-01

    Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip latitude 5.5°N to study electron density and electric field irregularities during spread F. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of electron density fluctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150-300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165-178 km, in the intermediate scale size range, observed during this flight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200-330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms-1. These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.Key words: Ionosphere (equatorial ionosphere; ionospheric irregularities - Radio science (ionospheric physics

  20. Multiple frequency radar observations of high-latitude E region irregularities in the HF modified ionosphere

    International Nuclear Information System (INIS)

    Noble, S.T.; Djuth, F.T.; Jost, R.J.

    1987-01-01

    In September 1983, experiments were conducted in Scandinavia using the high-power heating facility near Tromso, Norway. The purpose of the HF ionospheric modification experiments was to investigate the behavior of artificially produced E region irregularities at auroral latitudes. The majority of observations were made with backscatter radars operating at 46.9 and 143.8 MHz, but limited observations were also made at 21.4 and 140.0 MHz. These radars are sensitive to irregularities having scale lengths of between 1 and 7 m across the geomagnetic field lines. The growth and decay of the irregularities are scale length dependent with the shorter lengths growing and dissipating more rapidly than the longer lengths (e-folding growth times = 10 1 --10 2 ms; decay times = 10 2 --10 3 ms). During periods of full power ordinary mode heating, irregularities having peak cross sections of 10 4 m 2 at 46.9 MHz and 10 5 m 2 at 143.8 MHz are observed. However, the cross sections normally measured are 1 to 2 orders of magnitude smaller than the peak values. The cross sections are nonlinearly dependent on the HF power and begin to saturate at levels greater than 50--75 percent of full power. Past E and F region data from Arecibo are used in conjunction with the Tromso measurements to ascertain the relative roles played by various mechanisms in exciting irregularities. In the E region, the results tend to favor those instability processes which operate at the upper hybrid resonance level (e.g., thermal parametric and resonance instabilities) over those that operate at the reflection level (e.g., parametric decay instability). However, it is likely that anyh of the mechanisms studied could at times contribute to irregularity production in the E regions

  1. The majority of irregular menstrual cycles in adolescence are ovulatory: results of a prospective study.

    Science.gov (United States)

    Peña, Alexia S; Doherty, Dorota A; Atkinson, Helen C; Hickey, Martha; Norman, Robert J; Hart, Roger

    2018-03-01

    While ovulation is most likely to occur in adolescent girls with regular menstrual cycles, there are limited data on the incidence of ovulation in girls with irregular menstrual cycles in early postmenarcheal years. The aim of the study was to evaluate the presence of ovulation in healthy postmenarcheal girls with irregular menstrual cycles. Prospective cohort study over 12 weeks including 40 healthy postmenarcheal girls recruited from the population-based cohort of adolescents from Western Australian Pregnancy Cohort (Raine) Study with irregular menstrual cycles defined by either menstrual cycles 35 days in duration or cycle length that varied from month to month by >4 days according to menstrual diaries. Ovulation defined by urinary pregnanediol-3α-glucuronide/creatinine measurements higher than three times above minimum value obtained from 12 samples (1 per week). Forty girls (37 Caucasians) with irregular menstrual cycles aged 15.1 (median (IQR) 14.9-15.4) years who were 2.3 (1.9-3.3) years postmenarche were assessed. Urinary pregnanediol-3α-glucuronide/creatinine values identified that 33 girls (82.5%) ovulated during the 3 months of observation and 7 girls had anovulatory cycles. Menstrual diaries collected for a median (IQR) of 159 (137.5-188.2) days showed median minimal and maximum menstrual cycle duration of 24 (11.5-29) and 38.5 (35-48) days, respectively. A large proportion of healthy adolescent girls with irregular menstrual cycles are still ovulating despite irregular and infrequent menses. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  2. THE STELLAR AND GAS KINEMATICS OF THE LITTLE THINGS DWARF IRREGULAR GALAXY NGC 1569

    International Nuclear Information System (INIS)

    Johnson, Megan; Hunter, Deidre A.; Zhang, Hong-Xin; Herrmann, Kimberly; Oh, Se-Heon; Elmegreen, Bruce; Brinks, Elias; Tollerud, Erik

    2012-01-01

    In order to understand the formation and evolution of Magellanic-type dwarf irregular (dIm) galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, σ z , coupled with the maximum rotational velocity derived from H I observations, V max , gives a measure of how kinematically hot the galaxy is, and, therefore, indicates its structure. We conclude that the stars in NGC 1569 are in a thick disk with a V max /σ z = 2.4 ± 0.7. In addition to the structure, we analyze the ionized gas kinematics from O III observations along the morphological major axis. These data show evidence for outflow from the inner starburst region and a potential expanding shell near supermassive star cluster (SSC) A. When compared to the stellar kinematics, the velocity dispersion of the stars increases in the region of SSC A supporting the hypothesis of an expanding shell. The stellar kinematics closely follow the motion of the gas. Analysis of high-resolution H I data clearly reveals the presence of an H I cloud that appears to be impacting the eastern edge of NGC 1569. Also, an ultra-dense H I cloud can be seen extending to the west of the impacting H I cloud. This dense cloud is likely the remains of a dense H I bridge that extended through what is now the central starburst area. The impacting H I cloud was the catalyst for the starburst, thus turning the dense gas into stars over a short timescale, ∼1 Gyr. We performed a careful study of the spectral energy distribution using infrared, optical, and ultraviolet photometry, producing a state-of-the-art mass model for the stellar disk. This mass modeling shows that stars dominate the gravitational potential in the inner 1 kpc. The dynamical mass of NGC 1569, derived from V max , shows that the disk may be dark matter deficient in the inner region, although, when compared to the

  3. THE STELLAR AND GAS KINEMATICS OF THE LITTLE THINGS DWARF IRREGULAR GALAXY NGC 1569

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Megan [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Hunter, Deidre A.; Zhang, Hong-Xin; Herrmann, Kimberly [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Oh, Se-Heon [International Centre for Radio Astronomy Research (ICRAR), University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Elmegreen, Bruce [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Hts., NY 10598 (United States); Brinks, Elias [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield, AL10 9AB (United Kingdom); Tollerud, Erik, E-mail: mjohnson@nrao.edu, E-mail: dah@lowell.edu, E-mail: hxzhang@lowell.edu, E-mail: herrmann@lowell.edu, E-mail: se-heon.oh@uwa.edu.au, E-mail: bge@us.ibm.com, E-mail: E.Brinks@herts.ac.uk, E-mail: etolleru@uci.edu [Center For Cosmology, Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States)

    2012-11-01

    In order to understand the formation and evolution of Magellanic-type dwarf irregular (dIm) galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, {sigma}{sub z}, coupled with the maximum rotational velocity derived from H I observations, V{sub max}, gives a measure of how kinematically hot the galaxy is, and, therefore, indicates its structure. We conclude that the stars in NGC 1569 are in a thick disk with a V{sub max}/{sigma}{sub z} = 2.4 {+-} 0.7. In addition to the structure, we analyze the ionized gas kinematics from O III observations along the morphological major axis. These data show evidence for outflow from the inner starburst region and a potential expanding shell near supermassive star cluster (SSC) A. When compared to the stellar kinematics, the velocity dispersion of the stars increases in the region of SSC A supporting the hypothesis of an expanding shell. The stellar kinematics closely follow the motion of the gas. Analysis of high-resolution H I data clearly reveals the presence of an H I cloud that appears to be impacting the eastern edge of NGC 1569. Also, an ultra-dense H I cloud can be seen extending to the west of the impacting H I cloud. This dense cloud is likely the remains of a dense H I bridge that extended through what is now the central starburst area. The impacting H I cloud was the catalyst for the starburst, thus turning the dense gas into stars over a short timescale, {approx}1 Gyr. We performed a careful study of the spectral energy distribution using infrared, optical, and ultraviolet photometry, producing a state-of-the-art mass model for the stellar disk. This mass modeling shows that stars dominate the gravitational potential in the inner 1 kpc. The dynamical mass of NGC 1569, derived from V{sub max}, shows that the disk may be dark matter deficient in the inner

  4. Spatial relationship of 1-meter equatorial spread-F irregularities and depletions in total electron content

    International Nuclear Information System (INIS)

    Tsunoda, R.T.; Towle, D.M.

    1979-01-01

    An experiment was conducted at Kwajalein Atoll, Marshall Islands to investigate the spatial relationship of 1-m equatorial spread-F irregularities to total electron content (TEC) depletions. A high-power radar was operated (1) in a backscatter scan mode to spatially map the distribution of 1-m irregularities, and (2) in a dual-frequency, satellite-track mode to obtain the longitudinal TEC variations. We show that radar backscatter ''plumes'' found in the disturbed, nighttime equatorial ionosphere are longitudinally coincident with TEC depletions. We suggest that the TEC depletions are probably due to the presence of plasma ''bubbles'' in the equatorial F layer

  5. Controllable irregular melting induced by atomic segregation in bimetallic clusters with fabricating different initial configurations

    International Nuclear Information System (INIS)

    Li Guojian; Liu Tie; Wang Qiang; Lue Xiao; Wang Kai; He Jicheng

    2010-01-01

    The melting process of Co, Co-Cu and Co-Ni clusters with different initial configurations is studied in molecular dynamics by a general embedded atom method. An irregular melting, at which energy decreases as the temperature increase near the melting point, is found in the onion-like Co-Cu-Co clusters, but not in the mixed Co-Cu and onion-like Co-Ni-Co clusters. From the analysis of atomic distributions and energy variation, the results indicate the irregular melting is induced by Cu atomic segregation. Furthermore, this melting can be controlled by doping hetero atoms with different surface energies and controlling their distributions.

  6. Characterization of the low latitude plasma density irregularities observed using C/NOFS and SCINDA data

    Science.gov (United States)

    Andima, Geoffrey; Amabayo, Emirant B.; Jurua, Edward; Cilliers, Pierre J.

    2018-01-01

    Complex electrodynamic processes over the low latitude region often result in post sunset plasma density irregularities which degrade satellite communication and navigation. In order to forecast the density irregularities, their occurrence time, duration and location need to be quantified. Data from the Communication/Navigation Outage Forecasting System (C/NOFS) satellite was used to characterize the low latitude ion density irregularities from 2011 to 2013. This was supported by ground based data from the SCIntillation Network Decision Aid (SCINDA) receivers at Makerere (Geographic coordinate 32.6°E, 0.3°N, and dip latitude -9.3°N) and Nairobi (Geographic coordinate 36.8°E, -1.3°N, and dip latitude -10.8°N). The results show that irregularities in ion density have a daily pattern with peaks from 20:00 to 24:00 Local Time (LT). Scintillation activity at L band and VHF over East Africa peaked in 2011 and 2012 from 20:00 to 24:00 LT, though in many cases scintillation at VHF persisted longer than that at L band. A longitudinal pattern in ion density irregularity occurrence was observed with peaks over 135-180°E and 270-300°E. The likelihood of ion density irregularity occurrence decreased with increasing altitude. Analysis of C/NOFS zonal ion drift velocities showed that the largest nighttime and daytime drifts were in 270-300°E and 300-330°E longitude regions respectively. Zonal irregularity drift velocities over East Africa were for the first time estimated from L-band scintillation indices. The results show that the velocity of plasma density irregularities in 2011 and 2012 varied daily, and hourly in the range of 50-150 m s-1. The zonal drift velocity estimates from the L-band scintillation indices had good positive correlation with the zonal drift velocities derived from VHF receivers by the spaced receiver technique.

  7. Regular-, irregular-, and pseudo-character processing in Chinese: The regularity effect in normal adult readers

    Directory of Open Access Journals (Sweden)

    Dustin Kai Yan Lau

    2014-03-01

    Full Text Available Background Unlike alphabetic languages, Chinese uses a logographic script. However, the pronunciation of many character’s phonetic radical has the same pronunciation as the character as a whole. These are considered regular characters and can be read through a lexical non-semantic route (Weekes & Chen, 1999. Pseudocharacters are another way to study this non-semantic route. A pseudocharacter is the combination of existing semantic and phonetic radicals in their legal positions resulting in a non-existing character (Ho, Chan, Chung, Lee, & Tsang, 2007. Pseudocharacters can be pronounced by direct derivation from the sound of its phonetic radical. Conversely, if the pronunciation of a character does not follow that of the phonetic radical, it is considered as irregular and can only be correctly read through the lexical-semantic route. The aim of the current investigation was to examine reading aloud in normal adults. We hypothesized that the regularity effect, previously described for alphabetical scripts and acquired dyslexic patients of Chinese (Weekes & Chen, 1999; Wu, Liu, Sun, Chromik, & Zhang, 2014, would also be present in normal adult Chinese readers. Method Participants. Thirty (50% female native Hong Kong Cantonese speakers with a mean age of 19.6 years and a mean education of 12.9 years. Stimuli. Sixty regular-, 60 irregular-, and 60 pseudo-characters (with at least 75% of name agreement in Chinese were matched by initial phoneme, number of strokes and family size. Additionally, regular- and irregular-characters were matched by frequency (low and consistency. Procedure. Each participant was asked to read aloud the stimuli presented on a laptop using the DMDX software. The order of stimuli presentation was randomized. Data analysis. ANOVAs were carried out by participants and items with RTs and errors as dependent variables and type of stimuli (regular-, irregular- and pseudo-character as repeated measures (F1 or between subject

  8. Understanding Alzheimer's

    Science.gov (United States)

    ... Navigation Bar Home Current Issue Past Issues Understanding Alzheimer's Past Issues / Fall 2007 Table of Contents For ... and brain scans. No treatment so far stops Alzheimer's. However, for some in the disease's early and ...

  9. Optimized Irregular Low-Density Parity-Check Codes for Multicarrier Modulations over Frequency-Selective Channels

    Directory of Open Access Journals (Sweden)

    Valérian Mannoni

    2004-09-01

    Full Text Available This paper deals with optimized channel coding for OFDM transmissions (COFDM over frequency-selective channels using irregular low-density parity-check (LDPC codes. Firstly, we introduce a new characterization of the LDPC code irregularity called “irregularity profile.” Then, using this parameterization, we derive a new criterion based on the minimization of the transmission bit error probability to design an irregular LDPC code suited to the frequency selectivity of the channel. The optimization of this criterion is done using the Gaussian approximation technique. Simulations illustrate the good performance of our approach for different transmission channels.

  10. Embodied Understanding

    Directory of Open Access Journals (Sweden)

    Mark Leonard Johnson

    2015-06-01

    Full Text Available Western culture has inherited a view of understanding as an intellectual cognitive operation of grasping of concepts and their relations. However, cognitive science research has shown that this received intellectualist conception is substantially out of touch with how humans actually make and experience meaning. The view emerging from the mind sciences recognizes that understanding is profoundly embodied, insofar as our conceptualization and reasoning recruit sensory, motor, and affective patterns and processes to structure our understanding of, and engagement with, our world. A psychologically realistic account of understanding must begin with the patterns of ongoing interaction between an organism and its physical and cultural environments and must include both our emotional responses to changes in our body and environment, and also the actions by which we continuously transform our experience. Consequently, embodied understanding is not merely a conceptual/propositional activity of thought, but rather constitutes our most basic way of being in, and engaging with, our surroundings in a deep visceral manner.

  11. Sedimentation of bidisperse, uncharged colloidal sphere suspensions: Influence of viscosity and irregular surfaces

    NARCIS (Netherlands)

    Thies-Weesie, Dominique M. E.; Philipse, Albert P.; Lekkerkerker, Henk N. W.

    1996-01-01

    The sedimentation velocity of uncharged, nonaggregated silica spheres under gravity is strongly reduced after addition of small amounts of nonsedimenting small spheres. This reduction is largely due to surface irregularities on a nanoscale of the large spheres at which a limited number of small

  12. Analysis of Mid-Latitude Plasma Density Irregularities in the Presence of Finite Larmor Radius Effects

    Science.gov (United States)

    Sotnikov, V. I.; Kim, T. C.; Mishin, E. V.; Kil, H.; Kwak, Y. S.; Paraschiv, I.

    2017-12-01

    Ionospheric irregularities cause scintillations of electromagnetic signals that can severely affect navigation and transionospheric communication, in particular during space storms. At mid-latitudes the source of F-region Field Aligned Irregularities (FAI) is yet to be determined. They can be created in enhanced subauroral flow channels (SAI/SUBS), where strong gradients of electric field, density and plasma temperature are present. Another important source of FAI is connected with Medium-scale travelling ionospheric disturbances (MSTIDs). Related shear flows and plasma density troughs point to interchange and Kelvin-Helmholtz type instabilities as a possible source of plasma irregularities. A model of nonlinear development of these instabilities based on the two-fluid hydrodynamic description with inclusion of finite Larmor radius effects will be presented. This approach allows to resolve density irregularities on the meter scale. A numerical code in C language to solve the derived nonlinear equations for analysis of interchange and flow velocity shear instabilities in the ionosphere was developed. This code will be used to analyze competition between interchange and Kelvin-Helmholtz instabilities in the mid-latitude region. The high-resolution simulations with continuous density and velocity profiles will be driven by the ambient conditions corresponding to the in situ data obtained during the 2016 Daejeon (Korea) and MU (Japan) radar campaign and data collected simultaneously by the Swarm satellites passed over Korea and Japan. PA approved #: 88ABW-2017-3641

  13. Metaphyseal cortical irregularities in children: A new perspective on a multi-focal growth variant

    International Nuclear Information System (INIS)

    Keats, T.E.; Joyce, J.M.

    1984-01-01

    The occurrence of metaphyseal cortical irregularities in adolescents in many different bones indicates a commonality of these lesions as a variation of normal growth, rater than a stress or avulsive by-product. The histologically recognized incomplete nature of the metaphysical cortex in children offers an attractive explanation for this phenomenon. (orig.)

  14. Rocket observation of electron density irregularities in the lower E region

    International Nuclear Information System (INIS)

    Watanabe, Yuzo; Nakamura, Yoshiharu; Amemiya, Hiroshi.

    1990-01-01

    Local ionospheric electron density irregularities in the scale size of 3 m to 300 m have been measured on the ascending path from 74 km to 93 km by a fix biased Langmuir probe on board the S-310-16 sounding rocket. The rocket was launched at 22:40:00 on February 1, 1986 from Kagoshima Space Center in Japan. It is found from frequency analysis of the data that the spectral index of the irregularities is 0.9 to 1.8 and the irregularity amplitude is 1 to 15 %. The altitude where the amplitude reaches its maximum is 88 km. The generation mechanism of these irregularities is explained by the neutral turbulence theory, which indicates that the spectral index is 5/3 and has been confirmed by a chemical release experiment using rockets over India to be valid up to about 110 km. From frequency analysis of the data observed during the descent in the lower E region, we have found that the rocket-wake effect becomes larger when the probe is situated near the edge of the rocket-wake, and that this is also the case even when the rocket-wake effect does not clearly appear in the DC current signal which approximately changes in proportion to the electron density, where the probe is completely situated inside the rocket-wake region. (author)

  15. An irregular grid approach for pricing high-dimensional American options

    NARCIS (Netherlands)

    Berridge, S.J.; Schumacher, J.M.

    2008-01-01

    We propose and test a new method for pricing American options in a high-dimensional setting. The method is centered around the approximation of the associated complementarity problem on an irregular grid. We approximate the partial differential operator on this grid by appealing to the SDE

  16. Post-midnight equatorial irregularity distributions and vertical drift velocity variations during solstices

    Science.gov (United States)

    Su, S.-Y.; Liu, C. H.; Chao, C.-K.

    2018-04-01

    Longitudinal distributions of post-midnight equatorial ionospheric irregularity occurrences observed by ROCSAT-1 (1st satellite of the Republic of China) during moderate to high solar activity years in two solstices are studied with respect to the vertical drift velocity and density variations. The post-midnight irregularity distributions are found to be similar to the well-documented pre-midnight ones, but are different from some published distributions taken during solar minimum years. Even though the post-midnight ionosphere is sinking in general, longitudes of frequent positive vertical drift and high density seems to coincide with the longitudes of high irregularity occurrences. Large scatters found in the vertical drift velocity and density around the dip equator in different ROCSAT-1 orbits indicate the existence of large and frequent variations in the vertical drift velocity and density that seem to be able to provide sufficient perturbations for the Rayleigh-Taylor (RT) instability to cause the irregularity occurrences. The need of seeding agents such as gravity waves from atmospheric convective clouds to initiate the Rayleigh-Taylor instability may not be necessary.

  17. Lateralized effects of orthographical irregularity and auditory memory load on the kinematics of transcription typewriting.

    Science.gov (United States)

    Bloemsaat, Gijs; Van Galen, Gerard P; Meulenbroek, Ruud G J

    2003-05-01

    This study investigated the combined effects of orthographical irregularity and auditory memory load on the kinematics of finger movements in a transcription-typewriting task. Eight right-handed touch-typists were asked to type 80 strings of ten seven-letter words. In half the trials an irregularly spelt target word elicited a specific key press sequence of either the left or right index finger. In the other trials regularly spelt target words elicited the same key press sequence. An auditory memory load was added in half the trials by asking participants to remember the pitch of a tone during task performance. Orthographical irregularity was expected to slow down performance. Auditory memory load, viewed as a low level stressor, was expected to affect performance only when orthographically irregular words needed to be typed. The hypotheses were confirmed. Additional analysis showed differential effects on the left and right hand, possibly related to verbal-manual interference and hand dominance. The results are discussed in relation to relevant findings of recent neuroimaging studies.

  18. Irregular migration and informal economy in Southern and Central-Eastern Europe: breaking the vicious cycle?

    Science.gov (United States)

    Maroukis, Thanos; Iglicka, Krystyna; Gmaj, Katarzyna

    2011-01-01

    The flexible and cheap labour that European “post-industrial” economies are in need of is often facilitated by undeclared labour. The undocumented migrant, from his/her part, relatively easily finds work that suits his -- at least initial -- plans. What lies behind this nexus between irregular migration and informal economy? To what extent can this nexus be attributed to the structural features of the so-called “secondary”, as opposed to “primary”, labour market? And how does migration policy correlate with this economic context and lead to the entrapment of migrants in irregularity? Finally, can this vicious cycle of interests and life-strategies be broken and what does the experience of the migrants indicate in this respect? This paper addresses these questions via an exploration of the grounds upon which irregular migration and the shadow economy complement each other in southern Europe (SE) and central and Eastern Europe (CEE) (two regions at different points in the migration cycle). In doing so, the dynamic character of the nexus between informal economy and irregular migration will come to the fore, and the abstract identity of the “average” undocumented migrant will be deconstructed.

  19. PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yu [State Key Laboratory of Astronautic Dynamics, Xi’an Satellite Control Center, Xi’an 710043 (China); Baoyin, Hexi, E-mail: jiangyu_xian_china@163.com [School of Aerospace Engineering, Tsinghua University, Beijing 100084 (China)

    2016-11-01

    The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

  20. Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

    Science.gov (United States)

    De Moraes, Carlos Gustavo V.; Prata, Tiago S.; Liebmann, Jeffrey; Ritch, Robert

    2010-01-01

    Recent advances in tonometry have led to the development of a number of devices with differing clinical applications. Their role in cases of abnormal corneal thickness and surface irregularities is particularly important, as inaccurate estimation of the true intraocular pressure (IOP) in such cases may lead to suboptimal evaluation. The purpose of the present review was to evaluate the accuracy of the most widely used devices in cases of corneal thickness and surface irregularities, based on a survey of the published literature. The analysis was based on a Medline search focusing mainly on papers that have evaluated the devices’ accuracy with respect to corneal thickness and irregularities. Nine device types (Goldmann tonometer, Tono-Pen, Perkins tonometer, Ocular Response Analyzer, non-contact tonometer, pneumatonometer, I-Care rebound tonometer, Pascal dynamic contour tonometer (DCT) and Phosphene tonometer) were described in detail. Moreover, the physical principles and major utility of each tonometer were compared. Each of the many different commercially available tonometers has specific advantages and disadvantages. New non-invasive technologies are getting closer to a precise estimation of the true IOP. However, among all tonometers, none is highly accurate when both corneal thickness and surface irregularities are present. Fifty years after its development, Goldmann tonometry remains the gold standard to which all other devices are compared.

  1. Simultaneous radar and spaced receiver VHF scintillation observations of ESF irregularities

    Directory of Open Access Journals (Sweden)

    D. Tiwari

    2006-07-01

    Full Text Available Simultaneous observations of equatorial spread F (ESF irregularities made on 10 nights during March-April 1998 and 1999, using an 18-MHz radar at Trivandrum (77° E, 8.5° N, dip 0.5° N and two spaced receivers recording scintillations on a 251-MHz signal at Tirunelveli (77.8° E, 8.7° N, dip 0.4° N, have been used to study the evolution of Equatorial Spread F (ESF irregularities. Case studies have been carried out on the day-to-day variability in ESF structure and dynamics, as observed by 18-MHz radar, and with spaced receiver measurements of average zonal drift Vo of the 251-MHz radio wave diffraction pattern on the ground, random velocity Vc, which is a measure of random changes in the characteristics of scintillation-producing irregularities, and maximum cross-correlation CI of the spaced receivers signals. Results show that in the initial phase of plasma bubble development, the greater the maximum height of ESF irregularities responsible for the radar backscatter, the greater the decorrelation is of the spaced receiver scintillation signals, indicating greater turbulence. The relationship of the maximum spectral width derived from the radar observations and CI also supports this result.

  2. Simultaneous radar and spaced receiver VHF scintillation observations of ESF irregularities

    Directory of Open Access Journals (Sweden)

    D. Tiwari

    2006-07-01

    Full Text Available Simultaneous observations of equatorial spread F (ESF irregularities made on 10 nights during March-April 1998 and 1999, using an 18-MHz radar at Trivandrum (77° E, 8.5° N, dip 0.5° N and two spaced receivers recording scintillations on a 251-MHz signal at Tirunelveli (77.8° E, 8.7° N, dip 0.4° N, have been used to study the evolution of Equatorial Spread F (ESF irregularities. Case studies have been carried out on the day-to-day variability in ESF structure and dynamics, as observed by 18-MHz radar, and with spaced receiver measurements of average zonal drift Vo of the 251-MHz radio wave diffraction pattern on the ground, random velocity Vc, which is a measure of random changes in the characteristics of scintillation-producing irregularities, and maximum cross-correlation CI of the spaced receivers signals. Results show that in the initial phase of plasma bubble development, the greater the maximum height of ESF irregularities responsible for the radar backscatter, the greater the decorrelation is of the spaced receiver scintillation signals, indicating greater turbulence. The relationship of the maximum spectral width derived from the radar observations and CI also supports this result.

  3. ARCAD3-SAFARI coordinated study of auroral and polar F-region ionospheric irregularities

    International Nuclear Information System (INIS)

    Villain, J.P.; Hanuise, C.; Beghin, C.

    1985-01-01

    Simultaneous observations of F-region ionospheric irregularities have been performed with the SAFARI ground based HF radars and the ISOPROBE experiment on board the AUREOL-3 satellite. Among seven orbits during which the satellite trajectory was directly in the radar beam or in the vicinity, four of them have been analysed in detail. The spectral power of the electron density variations ΔNe/Ne has been calculated for wavelengths between 20 m and 1 km from the ISOPROBE high time resolution thermal plasma measurements. One spectrum is obtained every 1.2 sec., which corresponds to about 10 km along the satellite trajectory. The SAFARI experiment is a set of two HF coherent radars located at Lycksele (Sweden) and Oulu (Finland). These radars are sensitive to F-region ionospheric irregularities of 10 m wavelength in the polar and auroral ionosphere. The phase velocity of the irregularities obtained from the Doppler spectrum is related to the ambient plasma drift. The presence of echoes observed with the SAFARI radars is compared with the spectral power of the electron density variations deduced from the ISOPROBE in-situ measurements. A good agreement is found between the two sets of observations and a numerical value of the spectral power corresponding to detection of echoes by the radar is given. A synoptical view of the event is given and interpreted according to the existing theories on plasma irregularities

  4. The Marine Corps Civil Military Operations (CMO) Capability: Inadequate for Current and Future Irregular Environments

    Science.gov (United States)

    2011-05-02

    the 2011 National Military Strategy contend and numerous analysts posit, that the United States will continue to prosecute irregular warfare or a...think tank reports, and the ruminations of various luminaries that the United States will be involved in inegular wmfare throughout the remainder of

  5. Short-term magnetic field alignment variations of equatorial ionospheric irregularities

    International Nuclear Information System (INIS)

    Johnson, A.L.

    1988-01-01

    The ionospheric irregularities that cause equatorial scintillation are elongated along the north-south magnetic field lines. During a 1981 field campaign at Ascension Island, 250-MHz receivers were spaced from 300 m to 1.6 km along the field lines, and the signals received from the Marisat satellite were cross correlated. Data collected during eight nights of fading showed a linear relationship between fading rate and cross correlation. The alignment of the antennas was adjusted to give a zero time lag between the widely spaced receivers with a measurement accuracy of 0.03 s. Since the average irregularity velocity was 125 m/s, this time accuracy translated to an angular measurement accuracy of 0.1 deg. During a 4-hour period of nightly fading, occasional differences in time of arrival were noted that corresponded to a tilt in the north-south alignment of + or - 1 deg. Data from several nights of fading were analyzed, and each night exhibited the same variance in the north-south irregularity alignment. It is postulated that the shift in the measured peak correlation may have been caused by patches of irregularities at different altitudes where the magnetic field lines have a slightly different direction. 13 references

  6. The governance of international migration in Turkey and Morocco: Irregular migrants’ access to right to stay

    NARCIS (Netherlands)

    Üstübici Önay, A.E.

    2015-01-01

    This thesis analyses migrant experiences of illegality in Turkey and Morocco by taking into account how both countries responded to increasing pressure by the European Union to govern irregular migration within their territories. In dialogue with literatures on the legal production of migrant

  7. A Strategy of Attrition through Enforcement: The Unmaking of Irregular Migration in Malaysia

    OpenAIRE

    Choo Chin Low

    2017-01-01

    This article reviews Malaysia's attempt to achieve zero migration irregularity by focusing on workplace enforcement, and examines how Malaysia's migration control has become a struggle between the state and employers. Applying the framework of "enforcement through attrition", this research examines three newly introduced principles governing workplace enforcement: employer sanctions, the Strict Liability Principle, and the Employers' Mandatory Commitment. The shift to employers in Malaysia's ...

  8. Using Localised Quadratic Functions on an Irregular Grid for Pricing High-Dimensional American Options

    NARCIS (Netherlands)

    Berridge, S.J.; Schumacher, J.M.

    2004-01-01

    We propose a method for pricing high-dimensional American options on an irregular grid; the method involves using quadratic functions to approximate the local effect of the Black-Scholes operator.Once such an approximation is known, one can solve the pricing problem by time stepping in an explicit

  9. On total irregularity strength of caterpillar graphs with two leaves on each internal vertex

    Science.gov (United States)

    Rosyida, I.; Widodo; Indriati, D.

    2018-04-01

    Let G(V, E) be a graph. A function f from V(G)\\cup E(G) to the set {1, 2, …, k} is said to be a totally irregular total k-labeling of G if the weights of any two different vertices x and y in V (G) satisfy {w}f(x)\

  10. Modelling the Cost Performance of a Given Logistics Network Operating Under Regular and Irregular Conditions

    NARCIS (Netherlands)

    Janic, M.

    2009-01-01

    This paper develops an analytical model for the assessment of the cost performance of a given logistics network operating under regular and irregular (disruptive) conditions. In addition, the paper aims to carry out a sensitivity analysis of this cost with respect to changes of the most influencing

  11. Special Operations, Irregular Warfare, and Operational Art: A Theory of Special Operations

    Science.gov (United States)

    2013-12-10

    is mostly but not wholly a land phenomenon. Naval forces have combatted maritime irregulars such as pirates for millennia, for example see: Plutarch ...SW2502SocialMediaAndUW.html (accessed June 15, 2013). Plaster, John L. SOG: Secret Wars of America’s Commandos in Vietnam. New York: Simon & Schuster, 1997. Plutarch

  12. A Novel Energy Yields Calculation Method for Irregular Wind Farm Layout

    DEFF Research Database (Denmark)

    Hou, Peng; Hu, Weihao; Soltani, Mohsen

    2015-01-01

    Due to the increasing size of offshore wind farm, the impact of the wake effect on energy yields become more and more evident. The Seafloor topography would limit the layout of the wind farm so that irregular layout is usually adopted inlarge scale offshore wind farm. However, the calculation...

  13. Two media method for linear attenuation coefficient determination of irregular soil samples

    International Nuclear Information System (INIS)

    Vici, Carlos Henrique Georges

    2004-01-01

    In several situations of nuclear applications, the knowledge of gamma-ray linear attenuation coefficient for irregular samples is necessary, such as in soil physics and geology. This work presents the validation of a methodology for the determination of the linear attenuation coefficient (μ) of irregular shape samples, in such a way that it is not necessary to know the thickness of the considered sample. With this methodology irregular soil samples (undeformed field samples) from Londrina region, north of Parana were studied. It was employed the two media method for the μ determination. It consists of the μ determination through the measurement of a gamma-ray beam attenuation by the sample sequentially immersed in two different media, with known and appropriately chosen attenuation coefficients. For comparison, the theoretical value of μ was calculated by the product of the mass attenuation coefficient, obtained by the WinXcom code, and the measured value of the density sample. This software employs the chemical composition of the samples and supplies a table of the mass attenuation coefficients versus the photon energy. To verify the validity of the two media method, compared with the simple gamma ray transmission method, regular pome stone samples were used. With these results for the attenuation coefficients and their respective deviations, it was possible to compare the two methods. In this way we concluded that the two media method is a good tool for the determination of the linear attenuation coefficient of irregular materials, particularly in the study of soils samples. (author)

  14. Coherent and intermittent ensemble oscillations emerge from networks of irregular spiking neurons.

    Science.gov (United States)

    Hoseini, Mahmood S; Wessel, Ralf

    2016-01-01

    Local field potential (LFP) recordings from spatially distant cortical circuits reveal episodes of coherent gamma oscillations that are intermittent, and of variable peak frequency and duration. Concurrently, single neuron spiking remains largely irregular and of low rate. The underlying potential mechanisms of this emergent network activity have long been debated. Here we reproduce such intermittent ensemble oscillations in a model network, consisting of excitatory and inhibitory model neurons with the characteristics of regular-spiking (RS) pyramidal neurons, and fast-spiking (FS) and low-threshold spiking (LTS) interneurons. We find that fluctuations in the external inputs trigger reciprocally connected and irregularly spiking RS and FS neurons in episodes of ensemble oscillations, which are terminated by the recruitment of the LTS population with concurrent accumulation of inhibitory conductance in both RS and FS neurons. The model qualitatively reproduces experimentally observed phase drift, oscillation episode duration distributions, variation in the peak frequency, and the concurrent irregular single-neuron spiking at low rate. Furthermore, consistent with previous experimental studies using optogenetic manipulation, periodic activation of FS, but not RS, model neurons causes enhancement of gamma oscillations. In addition, increasing the coupling between two model networks from low to high reveals a transition from independent intermittent oscillations to coherent intermittent oscillations. In conclusion, the model network suggests biologically plausible mechanisms for the generation of episodes of coherent intermittent ensemble oscillations with irregular spiking neurons in cortical circuits. Copyright © 2016 the American Physiological Society.

  15. Eddy current heating of irregularly shaped plates by slow ramped fields

    International Nuclear Information System (INIS)

    Dresner, L.

    1979-01-01

    Theorems are presented for estimating eddy current heating of irregularly shaped plates by a perpendicular ramped field. The theorems, which are derived from two complementary variational principles, give upper and lower bounds to the eddy current heating. Illustrative results are given for rectangles, isosceles triangles, sectors of circular annuli, rhombuses, and L-shaped plates. A comparison is made with earlier work

  16. Metaphyseal cortical irregularities in children: A new perspective on a multi-focal growth variant

    Energy Technology Data Exchange (ETDEWEB)

    Keats, T.E.; Joyce, J.M.

    1984-07-01

    The occurrence of metaphyseal cortical irregularities in adolescents in many different bones indicates a commonality of these lesions as a variation of normal growth, rather than a stress or avulsive by-product. The histologically recognized incomplete nature of the metaphysical cortex in children offers an attractive explanation for this phenomenon.

  17. An Irregular Grid Approach for Pricing High-Dimensional American Options

    NARCIS (Netherlands)

    Berridge, S.J.; Schumacher, J.M.

    2004-01-01

    We propose and test a new method for pricing American options in a high-dimensional setting.The method is centred around the approximation of the associated complementarity problem on an irregular grid.We approximate the partial differential operator on this grid by appealing to the SDE

  18. Videokymography. Imaging and quantification of regular and irregular vocal fold vibrations

    NARCIS (Netherlands)

    Schutte, HK; Svec, JG; Sram, F; McCafferty, G; Coman, W; Carroll, R

    1996-01-01

    A newly developed imaging technique makes it possible to observe the vocal fold vibration pattern also under unstable conditions. In contrast to stroboscopy, which strongly relies on the regularity of the vibration under study videokymography enables the study of irregular patterns as well. The

  19. Spherical and irregular aberrations are important for the optimal performance of the human eye

    NARCIS (Netherlands)

    Nio, YK; Jansonius, NM; Fidler, [No Value; Geraghty, E; Norrby, S; Kooijman, AC

    Contrast sensitivity measured psychophysically at different levels of defocus can be used to evaluate the eye optics. Possible parameters of spherical and irregular aberrations, e.g, relative modulation transfer (RMT), myopic shift, and depth of focus, can be determined from these measurements. The

  20. Health care for irregular migrants: pragmatism across Europe: a qualitative study

    NARCIS (Netherlands)

    Dauvrin, M.; Lorant, V.; Sandhu, S.; Devillé, W.; Dia, H.; Dias, S.; Gaddini, A.; Ioannidis, E.; Jensen, N.K.; Kluge, U.; Mertaniemi, R.; Puigpinós i Riera, R.; Sárváry, A.; Straßmayr, C.; Stankunas, M.; Soares, J.J.F.; Welbel, M.; Priebe, S.

    2012-01-01

    Background Health services in Europe face the challenge of delivering care to a heterogeneous group of irregular migrants (IM). There is little empirical evidence on how health professionals cope with this challenge. This study explores the experiences of health professionals providing care to IM in

  1. The structure of plasma-density irregularities in the interplanetary medium

    International Nuclear Information System (INIS)

    Singleton, D.G.

    1975-01-01

    The conflict in the literature as to whether the plasma-density spatial spectrum of the irregularities in the interplanetary medium is of Gaussian or power law form is discussed. Particular attention is paid to the interplanetary scintillation effects ascribed to these irregularities. It is shown that the phase-screen theory of scintillations can be invoked to devise a set of critical tests which provide a means of discriminating between the conflicting hypotheses. Differences in the predicted behaviour of the single sensor temporal spectra of the scintillations for the two irregularity forms provide the main tests of the conflicting hypotheses. However, it is also shown that the two hypotheses lead to different forms of the variation of scintillation index with the observing frequency and the solar elongation of the scintillating source. Consideration is given to the optimum conditions for observing the Fourier and Bessel temporal spectra modulation which is due to the Fresnel filtering of the spatial spectrum. Determination of irregularity shape, orientation and motion in terms of this modulation is also discussed. (author)

  2. Gait Characteristics Associated with Trip-Induced Falls on Level and Sloped Irregular Surfaces

    Directory of Open Access Journals (Sweden)

    Andrew Merryweather

    2011-11-01

    Full Text Available Same level falls continue to contribute to an alarming number of slip/trip/fall injuries in the mining workforce. The objective of this study was to investigate how walking on different surface types and transverse slopes influences gait parameters that may be associated with a trip event. Gait analysis was performed for ten subjects on two orientations (level and sloped on smooth, hard surface (control and irregular (gravel, larger rocks surfaces. Walking on irregular surfaces significantly increased toe clearance compared to walking on the smooth surface. There was a significant (p < 0.05 decrease in cadence (steps/min, stride length (m, and speed (m/s from control to gravel to larger rocks. Significant changes in external rotation and increased knee flexion while walking on irregular surfaces were observed. Toe and heel clearance requirements increased on irregular surfaces, which may provide an explanation for trip-induced falls; however, the gait alterations observed in the experienced workers used as subjects would likely improve stability and recovery from a trip.

  3. Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

    Directory of Open Access Journals (Sweden)

    Carlos Gustavo V. De Moraes

    2008-01-01

    Each of the many different commercially available tonometers has specific advantages and disadvantages. New non-invasive technologies are getting closer to a precise estimation of the true IOP. However, among all tonometers, none is highly accurate when both corneal thickness and surface irregularities are present. Fifty years after its development, Goldmann tonometry remains the gold standard to which all other devices are compared.

  4. Experimental evidence of widespread regions of small-scale plasma irregularities in the magnetosphere

    International Nuclear Information System (INIS)

    Holmgren, G.; Kintner, P.M.

    1990-01-01

    Small-scale (≤ 1 km) plasma irregularities have previously been observed in situ from the E region to an altitude of 8,000 km. In this paper the authors report results from the Viking plasma wave experiments which extends the measurements of high-latitude irregularities in two ways: (1) they have acquired electron density fluctuation measurements up to an altitude of 13,500 km and (2) for the first time a measurement technique was used that made a phase velocity deduction possible from in situ measurements. The spacecraft was equipped with two spatially separated Langmuir probes, each with an ability to measure relative probe current fluctuations with frequencies from dc to about 400 Hz. Under certain assumptions the current fluctuations could be interpreted as relative plasma density fluctuations, δn e /n e . Data from this interferometric instrument has been used to infer the distribution and nature of plasma irregularities along Viking orbits. It is demonstrated that the interferometric technique offers great advantages compared to single point measurements in this kind of study. It is shown that the observed small-scale plasma irregularities are nondispersive and convecting with the background plasma. They exhibit a power law frequency spectrum as observed in the satellite reference frame. The spectral index varies with location. An attempt to map source regions by identifying regions of high power and shallow spectrums is made

  5. The normal squamocolumnar junction is circumferentially even and minimal irregularities are manifestations of gastroesophageal acid reflux.

    Science.gov (United States)

    Guerrero Garcia Hall, Mats; Wenner, Jörgen; Öberg, Stefan

    2017-03-01

    The macroscopic appearance of the normal squamocolumnar junction (SCJ) is often described as serrated with short projections of columnar mucosa that extend into the esophagus. As studies of the normal SCJ are sparse, the aim of this study was to test the hypothesis that the normal SCJ is even and that irregularities are manifestations of acid reflux. Fifty asymptomatic subjects and 149 patients with symptoms suggestive of gastroesophageal reflux disease underwent endoscopy and 48-h pH monitoring with a pH electrode positioned immediately above the SCJ. The shape of the SCJ was assessed according to the Z-line appearance classification and correlated with clinical characteristics and the degree of esophageal acid exposure in the most distal esophagus. Even SCJs without irregularities were significantly more common in asymptomatic subjects compared with patients (50% versus 10%, p acid exposure in individuals with an even SCJ was within normal limits. With increasing degree of irregularity of the SCJ, the frequency and duration of reflux episodes, the degree of distal esophageal acid exposure, and the prevalence of abnormal acid exposure increased progressively and significantly. The shape of the normal SCJ is even and also minimal irregularities are a consequence of acid reflux, likely due to the formation of small areas of metaplastic columnar mucosa.

  6. Meal irregularity and cardiometabolic consequences: results from observational and intervention studies

    NARCIS (Netherlands)

    Pot, G.K.; Almoosawi, S; Stephen, AM

    2016-01-01

    Studying irregular meal patterns fits in with the latest research focusing not only on what people eat but also when they eat, also called chrono-nutrition. Chrono-nutrition involves studying the impact of nutrition on metabolism via circadian patterns, including three aspects of time:

  7. Irregular wave functions of a hydrogen atom in a uniform magnetic field

    Science.gov (United States)

    Wintgen, D.; Hoenig, A.

    1989-01-01

    The highly excited irregular wave functions of a hydrogen atom in a uniform magnetic field are investigated analytically, with wave function scarring by periodic orbits considered quantitatively. The results obtained confirm that the contributions of closed classical orbits to the spatial wave functions vanish in the semiclassical limit. Their disappearance, however, is slow. This discussion is illustrated by numerical examples.

  8. Mental health care for irregular migrants in Europe: Barriers and how they are overcome

    NARCIS (Netherlands)

    Straßmayr, Christa; Matanov, Aleksandra; Priebe, Stefan; Barros, Henrique; Canavan, Reamonn; Díaz-Olalla, José Manuel; Gabor, Edina; Gaddini, Andrea; Greacen, Tim; Holcnerová, Petra; Kluge, Ulrike; Welbel, Marta; Nicaise, Pablo; Schene, Aart H.; Soares, Joaquim J. F.; Katschnig, Heinz

    2012-01-01

    Background: Irregular migrants (IMs) are exposed to a wide range of risk factors for developing mental health problems. However, little is known about whether and how they receive mental health care across European countries. The aims of this study were (1) to identify barriers to mental health care

  9. Analysis of the evolvement of contact wire wear irregularity in railway catenary based on historical data

    NARCIS (Netherlands)

    Wang, H.; Nunez Vicencio, Alfredo; Liu, Zhigang; Song, Yang; Duan, Fuchuan; Dollevoet, R.P.B.J.

    2017-01-01

    This paper studies the evolvement of the wear irregularity of contact wire using wire thickness data measured yearly from a section of railway catenary. The power spectral density and time–frequency representation based on the wavelet transform are employed for data analysis, with an emphasis on

  10. Research on making reactor buildings of irregular plan and elevation forms aseismatic

    International Nuclear Information System (INIS)

    Okawa, Izuru; Yamauchi, Yasuyuki

    1997-01-01

    The necessity of pursuing the possibility of irregular form buildings as the condition of location for construction is limited, and the rational and economical arrangement of equipment and piping is considered. In order to know the effect that irregular forms exert to the aseismatic ability of buildings, it is indispensable to develop the program for precision three-dimensional elastoplastic analysis at the time of earthquakes. As the means of solving the problem, the introduction of seismic insulation structure is conceivable. The investigation of seismic insulator and its modeling and the analysis of earthquake response were carried out, and the irregular form and the effect of seismic insulation were investigated, and the results of vibration test using test specimens were summarized. The concrete items of investigation were the characteristics of input earthquake motion, the techniques of analysis, the parametric study taking the input and various characteristics of buildings in consideration, and the synthetic assessment. The vibration table experiment and the static loading experiment for the purpose of grasping the response behavior in the case of irregular form of wall type and seismic insulation type structures were carried out, and the results are reported. (K.I.)

  11. Pricing and hedging high-dimensional American options : an irregular grid approach

    NARCIS (Netherlands)

    Berridge, S.; Schumacher, H.

    2002-01-01

    We propose and test a new method for pricing American options in a high dimensional setting. The method is centred around the approximation of the associated variational inequality on an irregular grid. We approximate the partial differential operator on this grid by appealing to the SDE

  12. PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

    International Nuclear Information System (INIS)

    Jiang, Yu; Baoyin, Hexi

    2016-01-01

    The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

  13. Young Japanese college students with dysmenorrhea have high frequency of irregular menstruation and premenstrual symptoms.

    Science.gov (United States)

    Fujiwara, Tomoko; Nakata, Rieko

    2007-01-01

    In this study, to estimate the current status of young women with menstrual disorders, the relation among dysmenorrhea, irregular menstruation and premenstrual symptoms was investigated by a questionnaire. Subjects ranging from 18 to 20 years old were recruited from 522 female students at Ashiya College in Japan. The intensity of dysmenorrhea was classified into 3 grades (score 1, not requiring analgesic; score 2, painful, requiring analgesic; score 3, painful, not relieved by analgesic). All participants were further divided into subsequent groups as having premenstrual symptoms or not and those having regular or irregular menstruation. Dysmenorrhea scores in the students with premenstrual symptoms or irregular menstruation were significantly higher than those without these symptoms (1.66+/-0.66 vs 1.41+/-0.59; 1.62+/-0.68 vs 1.49+/-0.61, respectively). There was no significant relation in the incidence between premenstrual symptoms and irregular menstruation. These findings suggest that considerable numbers of young women with dysmenorrhea are associated with premenstrual symptoms.

  14. Influence of the Wenchuan earthquake on self-reported irregular menstrual cycles in surviving women.

    Science.gov (United States)

    Li, Xiao-Hong; Qin, Lang; Hu, Han; Luo, Shan; Li, Lei; Fan, Wei; Xiao, Zhun; Li, Ying-Xing; Li, Shang-Wei

    2011-09-01

    To explore the influence of stress induced by the Wenchuan earthquake on the menstrual cycles of surviving women. Self-reports of the menstrual cycles of 473 women that survived the Wenchuan earthquake were analyzed. Menstrual regularity was defined as menses between 21 and 35 days long. The death of a child or the loss of property and social resources was verified for all surviving women. The severity of these losses was assessed and graded as high, little, and none. About 21% of the study participants reported that their menstrual cycles became irregular after the Wenchuan earthquake, and this percentage was significantly higher than before the earthquake (6%, p irregularity after the earthquake. Association analyses showed that some stressors of the Wenchuan earthquake were strongly associated with self-reports of menstrual irregularity, including the loss of children (RR: 1.58; 95% CI: 1.09, 2.28), large amounts of property (RR: 1.49; 95% CI: 1.03, 2.15), social resources (RR: 1.34; 95% CI: 1.00, 1.80) and the hormonal contraception use (RR: 1.62; 95% CI: 1.21, 1.83). Self-reported menstrual irregularity is common in women that survived the Wenchuan earthquake, especially in those who lost children, large amounts of property and social resources.

  15. Understanding Maple

    CERN Document Server

    Thompson, Ian

    2016-01-01

    Maple is a powerful symbolic computation system that is widely used in universities around the world. This short introduction gives readers an insight into the rules that control how the system works, and how to understand, fix, and avoid common problems. Topics covered include algebra, calculus, linear algebra, graphics, programming, and procedures. Each chapter contains numerous illustrative examples, using mathematics that does not extend beyond first-year undergraduate material. Maple worksheets containing these examples are available for download from the author's personal website. The book is suitable for new users, but where advanced topics are central to understanding Maple they are tackled head-on. Many concepts which are absent from introductory books and manuals are described in detail. With this book, students, teachers and researchers will gain a solid understanding of Maple and how to use it to solve complex mathematical problems in a simple and efficient way.

  16. Understanding physics

    CERN Document Server

    Mansfield, Michael

    2011-01-01

    Understanding Physics - Second edition is a comprehensive, yet compact, introductory physics textbook aimed at physics undergraduates and also at engineers and other scientists taking a general physics course. Written with today's students in mind, this text covers the core material required by an introductory course in a clear and refreshing way. A second colour is used throughout to enhance learning and understanding. Each topic is introduced from first principles so that the text is suitable for students without a prior background in physics. At the same time the book is designed to enable

  17. Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers

    Directory of Open Access Journals (Sweden)

    Elaine Cristina Marqueze

    2013-06-01

    Full Text Available OBJECTIVE: To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. METHODS: A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. RESULTS: Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively. The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05. Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively than moderately-active day-shift workers (116 and 73.3 mmHg, respectively (p < 0.05 as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively (p = 0.01. Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05. CONCLUSIONS: Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical

  18. Effects of irregular two-dimensional and three-dimensional surface roughness in turbulent channel flows

    International Nuclear Information System (INIS)

    De Marchis, M.; Napoli, E.

    2012-01-01

    Highlights: ► 3D irregular rough surfaces produce higher effects than those observed over 2D. ► Effective slope is a geometrical parameter representative of the roughness effects. ► 3D rough surfaces enhance the turbulence isotropization. ► 2D and 3D irregular roughness partially support the wall similarity. ► Irregular rough surfaces shear some features with regular rough walls. - Abstract: Wall-resolved Large Eddy Simulation of fully developed turbulent channel flows over two different rough surfaces is performed to investigate on the effects of irregular 2D and 3D roughness on the turbulence. The two geometries are obtained through the superimposition of sinusoidal functions having random amplitudes and different wave lengths. In the 2D configuration the irregular shape in the longitudinal direction is replicated in the transverse one, while in the 3D case the sinusoidal functions are generated both in streamwise and spanwise directions. Both channel walls are roughened in such a way as to obtain surfaces with statistically equivalent roughness height, but different shapes. In order to compare the turbulence properties over the two rough walls and to analyse the differences with a smooth wall, the simulations are performed at the same Reynolds number Re τ = 395. The same mean roughness height h = 0.05δ (δ the half channel height) is used for the rough walls. The roughness function obtained with the 3D roughness is larger than in the 2D case, although the two walls share the same mean height. Thus, the considered irregular 3D roughness is more effective in reducing the flow velocity with respect to the 2D roughness, coherently with the literature results that identified a clear dependence of the roughness function on the effective slope (see ), higher in the generated 3D rough wall. The analysis of higher-order statistics shows that the effects of the roughness, independently on its two- or three-dimensional shape, are mainly confined in the inner

  19. The effect of earthquake on architecture geometry with non-parallel system irregularity configuration

    Science.gov (United States)

    Teddy, Livian; Hardiman, Gagoek; Nuroji; Tudjono, Sri

    2017-12-01

    Indonesia is an area prone to earthquake that may cause casualties and damage to buildings. The fatalities or the injured are not largely caused by the earthquake, but by building collapse. The collapse of the building is resulted from the building behaviour against the earthquake, and it depends on many factors, such as architectural design, geometry configuration of structural elements in horizontal and vertical plans, earthquake zone, geographical location (distance to earthquake center), soil type, material quality, and construction quality. One of the geometry configurations that may lead to the collapse of the building is irregular configuration of non-parallel system. In accordance with FEMA-451B, irregular configuration in non-parallel system is defined to have existed if the vertical lateral force-retaining elements are neither parallel nor symmetric with main orthogonal axes of the earthquake-retaining axis system. Such configuration may lead to torque, diagonal translation and local damage to buildings. It does not mean that non-parallel irregular configuration should not be formed on architectural design; however the designer must know the consequence of earthquake behaviour against buildings with irregular configuration of non-parallel system. The present research has the objective to identify earthquake behaviour in architectural geometry with irregular configuration of non-parallel system. The present research was quantitative with simulation experimental method. It consisted of 5 models, where architectural data and model structure data were inputted and analyzed using the software SAP2000 in order to find out its performance, and ETAB2015 to determine the eccentricity occurred. The output of the software analysis was tabulated, graphed, compared and analyzed with relevant theories. For areas of strong earthquake zones, avoid designing buildings which wholly form irregular configuration of non-parallel system. If it is inevitable to design a

  20. Refraction traveltime tomography based on damped wave equation for irregular topographic model

    Science.gov (United States)

    Park, Yunhui; Pyun, Sukjoon

    2018-03-01

    Land seismic data generally have time-static issues due to irregular topography and weathered layers at shallow depths. Unless the time static is handled appropriately, interpretation of the subsurface structures can be easily distorted. Therefore, static corrections are commonly applied to land seismic data. The near-surface velocity, which is required for static corrections, can be inferred from first-arrival traveltime tomography, which must consider the irregular topography, as the land seismic data are generally obtained in irregular topography. This paper proposes a refraction traveltime tomography technique that is applicable to an irregular topographic model. This technique uses unstructured meshes to express an irregular topography, and traveltimes calculated from the frequency-domain damped wavefields using the finite element method. The diagonal elements of the approximate Hessian matrix were adopted for preconditioning, and the principle of reciprocity was introduced to efficiently calculate the Fréchet derivative. We also included regularization to resolve the ill-posed inverse problem, and used the nonlinear conjugate gradient method to solve the inverse problem. As the damped wavefields were used, there were no issues associated with artificial reflections caused by unstructured meshes. In addition, the shadow zone problem could be circumvented because this method is based on the exact wave equation, which does not require a high-frequency assumption. Furthermore, the proposed method was both robust to an initial velocity model and efficient compared to full wavefield inversions. Through synthetic and field data examples, our method was shown to successfully reconstruct shallow velocity structures. To verify our method, static corrections were roughly applied to the field data using the estimated near-surface velocity. By comparing common shot gathers and stack sections with and without static corrections, we confirmed that the proposed tomography

  1. Understanding Federalism.

    Science.gov (United States)

    Hickok, Eugene W., Jr.

    1990-01-01

    Urges returning to the original federalist debates to understand contemporary federalism. Reviews "The Federalist Papers," how federalism has evolved, and the centralization of the national government through acts of Congress and Supreme Court decisions. Recommends teaching about federalism as part of teaching about U.S. government…

  2. Understanding Energy

    Science.gov (United States)

    Menon, Deepika; Shelby, Blake; Mattingly, Christine

    2016-01-01

    "Energy" is a term often used in everyday language. Even young children associate energy with the food they eat, feeling tired after playing soccer, or when asked to turn the lights off to save light energy. However, they may not have the scientific conceptual understanding of energy at this age. Teaching energy and matter could be…

  3. Understanding the biological underpinnings of ecohydrological processes

    Science.gov (United States)

    Huxman, T. E.; Scott, R. L.; Barron-Gafford, G. A.; Hamerlynck, E. P.; Jenerette, D.; Tissue, D. T.; Breshears, D. D.; Saleska, S. R.

    2012-12-01

    Climate change presents a challenge for predicting ecosystem response, as multiple factors drive both the physical and life processes happening on the land surface and their interactions result in a complex, evolving coupled system. For example, changes in surface temperature and precipitation influence near-surface hydrology through impacts on system energy balance, affecting a range of physical processes. These changes in the salient features of the environment affect biological processes and elicit responses along the hierarchy of life (biochemistry to community composition). Many of these structural or process changes can alter patterns of soil water-use and influence land surface characteristics that affect local climate. Of the many features that affect our ability to predict the future dynamics of ecosystems, it is this hierarchical response of life that creates substantial complexity. Advances in the ability to predict or understand aspects of demography help describe thresholds in coupled ecohydrological system. Disentangling the physical and biological features that underlie land surface dynamics following disturbance are allowing a better understanding of the partitioning of water in the time-course of recovery. Better predicting the timing of phenology and key seasonal events allow for a more accurate description of the full functional response of the land surface to climate. In addition, explicitly considering the hierarchical structural features of life are helping to describe complex time-dependent behavior in ecosystems. However, despite this progress, we have yet to build an ability to fully account for the generalization of the main features of living systems into models that can describe ecohydrological processes, especially acclimation, assembly and adaptation. This is unfortunate, given that many key ecosystem services are functions of these coupled co-evolutionary processes. To date, both the lack of controlled measurements and experimentation

  4. Influence of initial stress, irregularity and heterogeneity on Love-type wave propagation in double pre-stressed irregular layers lying over a pre-stressed half-space

    Science.gov (United States)

    Singh, Abhishek Kumar; Das, Amrita; Parween, Zeenat; Chattopadhyay, Amares

    2015-10-01

    The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half-space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface of uppermost initially stressed heterogeneous layer and intermediate initially stressed isotropic layer. Dispersion equations are obtained in closed form for both cases of irregularities, distinctly. The effect of size and shape of irregularity, horizontal compressive initial stress, horizontal tensile initial stress, heterogeneity of the uppermost layer and width ratio of the layers on phase velocity of Love-type wave are the major highlights of the study. Comparative study has been made to identify the effects of different shapes of irregularity, presence of heterogeneity and initial stresses. Numerical computations have been carried out and depicted by means of graphs for the present study.

  5. Questioning the Homogenization of Irregular Migrants in Educational Policy: From (Il)Legal Residence to Inclusive Education

    Science.gov (United States)

    Hemelsoet, Elias

    2011-01-01

    In this article Elias Hemelsoet questions the way irregular migrants are approached in educational policymaking. In most cases, estimations of the number of irregular migrants serve--despite large methodological problems--as a starting point for policymaking. Given the very diverse composition of this group of people, the question is whether…

  6. Exploring Individual Differences in Irregular Word Recognition among Children with Early-Emerging and Late-Emerging Word Reading Difficulty

    Science.gov (United States)

    Steacy, Laura M.; Kearns, Devin M.; Gilbert, Jennifer K.; Compton, Donald L.; Cho, Eunsoo; Lindstrom, Esther R.; Collins, Alyson A.

    2017-01-01

    Models of irregular word reading that take into account both child- and word-level predictors have not been evaluated in typically developing children and children with reading difficulty (RD). The purpose of the present study was to model individual differences in irregular word reading ability among 5th grade children (N = 170), oversampled for…

  7. Understanding Translation

    DEFF Research Database (Denmark)

    Schjoldager, Anne Gram; Gottlieb, Henrik; Klitgård, Ida

    Understanding Translation is designed as a textbook for courses on the theory and practice of translation in general and of particular types of translation - such as interpreting, screen translation and literary translation. The aim of the book is to help you gain an in-depth understanding...... of the phenomenon of translation and to provide you with a conceptual framework for the analysis of various aspects of professional translation. Intended readers are students of translation and languages, but the book will also be relevant for others who are interested in the theory and practice of translation...... - translators, language teachers, translation users and literary, TV and film critics, for instance. Discussions focus on translation between Danish and English....

  8. Understanding Resilience

    Directory of Open Access Journals (Sweden)

    Gang eWu

    2013-02-01

    Full Text Available Resilience is the ability to adapt successfully in the face of stress and adversity. Stressful life events, trauma and chronic adversity can have a substantial impact on brain function and structure, and can result in the development of PTSD, depression and other psychiatric disorders. However, most individuals do not develop such illnesses after experiencing stressful life events, and are thus thought to be resilient. Resilience as successful adaptation relies on effective responses to environmental challenges and ultimate resistance to the deleterious effects of stress, therefore a greater understanding of the factors that promote such effects is of great relevance. This review focuses on recent findings regarding genetic, epigenetic, developmental, psychosocial and neurochemical factors that are considered essential contributors to the development of resilience. Neural circuits and pathways involved in mediating resilience are also discussed. The growing understanding of resilience factors will hopefully lead to the development of new pharmacological and psychological interventions for enhancing resilience and mitigating the untoward consequences.

  9. Understand electronics

    CERN Document Server

    Bishop, Owen

    2013-01-01

    Understand Electronics provides a readable introduction to the exciting world of electronics for the student or enthusiast with little previous knowledge. The subject is treated with the minimum of mathematics and the book is extensively illustrated.This is an essential guide for the newcomer to electronics, and replaces the author's best-selling Beginner's Guide to Electronics.The step-by-step approach makes this book ideal for introductory courses such as the Intermediate GNVQ.

  10. Understanding unemployment

    OpenAIRE

    Guillaume Rocheteau

    2006-01-01

    Modern economists have built models of the labor market, which isolate the market’s key drivers and describe the way these interact to produce particular levels of unemployment. One of the most popular models used by macroeconomists today is the search-matching model of equilibrium unemployment. We explain this model, and show how it can be applied to understand the way various policies, such as unemployment benefits, taxes, or technological changes, can affect the unemployment rate.

  11. Experimental modelling of wave amplification over irregular bathymetry for investigations of boulder transport by extreme wave events.

    Science.gov (United States)

    O'Boyle, Louise; Whittaker, Trevor; Cox, Ronadh; Elsäßer, Björn

    2017-04-01

    During the winter of 2013-2014 the west coast of Ireland was exposed to 6 storms over a period of 8 weeks with wind speeds equating to hurricane categories 3 and 4. During this period, the largest significant wave height recorded at the Marine Institute M6 wave buoy, approximately 300km from the site, was 13.6m (on 26th January 2014). However, this may not be the largest sea state of that winter, because the buoy stopped logging on 30th January and therefore failed to capture the full winter period. During the February 12th 2014 "Darwin" storm, the Kinsale Energy Gas Platform off Ireland's south coast measured a wave height of 25 m, which remains the highest wave measured off Ireland's coasts[1]. Following these storms, significant dislocation and transportation of boulders and megagravel was observed on the Aran Islands, Co. Galway at elevations of up to 25m above the high water mark and distances up to 220 m inland including numerous clasts with masses >50t, and at least one megagravel block weighing >500t [2]. Clast movements of this magnitude would not have been predicted from the measured wave heights. This highlights a significant gap in our understanding of the relationships between storms and the coastal environment: how are storm waves amplified and modified by interactions with bathymetry? To gain further understanding of wave amplification, especially over steep and irregular bathymetry, we have designed Froude-scaled wave tank experiments using the 3D coastal wave basin facility at Queen's University Belfast. The basin is 18m long by 16m wide with wave generation by means of a 12m wide bank of 24 top hinged, force feedback, sector carrier wave paddles at one end. The basin is equipped with gravel beaches to dissipate wave energy on the remaining three sides, capable of absorbing up to 99% of the incident wave energy, to prevent unwanted reflections. Representative bathymetry for the Aran Islands is modelled in the basin based on a high resolution

  12. Understanding Technology?

    Directory of Open Access Journals (Sweden)

    Erik Bendtsen

    2016-11-01

    Full Text Available We are facing radical changes in our ways of living in the nearest future. Not necessarily of our own choice, but because tchnological development is moving so fast, that it will have still greater impact on many aspects of our lives. We have seen the beginnings of that change within the latest 35 years or so, but according to newest research that change will speed up immensely in the nearest years to come. The impact of that change or these changes will affect our working life immensely as a consequence of automation. How these changes are brought about and which are their consequences in a broad sense is being attempted to be understood and guessed by researchers. No one knows for sure, but specific patterns are visible. This paper will not try to guess, what will come, but will rather try to understand the deepest ”nature” of technology in order to understand the driving factors in this development: the genesis of technology in a broad sense in order to contibute to the understanding of the basis for the expected development.

  13. Irregular incentives

    International Nuclear Information System (INIS)

    Cicchetti, M.A.

    1993-01-01

    Public utility regulation lacks a formal proxy for the economic profits that can be earned in an effectively competitive market if a firm is efficient or innovative. After all, public utility regulation operated on cost-plus basis. If a utility is efficient or innovative and lowers its costs, its typical reward is to have its rates reduced. This is a perverse incentive to motivate a utility to produce at the most efficient level. In addition, since regulation operates on this cost-plus basis, a utility can increase its net income, all other things being equal, by overinvesting in (or open-quotes gold-platingclose quotes) its system, another perverse incentive. Recognizing these flaws of regulation, academicians, utility executives, regulators, and legislators have tried over the last several years to implement incentive regulation plans that correct such perverse incentives. However, under many of the earnings-sharing or price-regulation incentive plans, the rewards for efficient production are not tied directly to measures under a company's control. In fact, such plans could prove highly detrimental to ratepayers and competitors of the regulated company and its affiliates. An incentive regulation plan that ties an appropriate reward for efficient production to specific efficiency gains is a better proxy of an effectively competitive environment. What's more, it is superior to an incentive plan that rewards circumstances beyond the company's control or self-serving manipulation. This is particularly true if no earnings cap is associated with the reward for efficiency. Rewards for efficient production should be tied to specific actions. A suitable incentive plan does not preclude appropriately derived flexible prices for certain products or services where warranted

  14. Understanding Magnitudes to Understand Fractions

    Science.gov (United States)

    Gabriel, Florence

    2016-01-01

    Fractions are known to be difficult to learn and difficult to teach, yet they are vital for students to have access to further mathematical concepts. This article uses evidence to support teachers employing teaching methods that focus on the conceptual understanding of the magnitude of fractions.

  15. Testing Understanding and Understanding Testing.

    Science.gov (United States)

    Pedersen, Jean; Ross, Peter

    1985-01-01

    Provides examples in which graphs are used in the statements of problems or in their solutions as a means of testing understanding of mathematical concepts. Examples (appropriate for a beginning course in calculus and analytic geometry) include slopes of lines and curves, quadratic formula, properties of the definite integral, and others. (JN)

  16. The Withdrawal of Health Care from Irregular Immigrants and Medical Conscientious Objection

    Directory of Open Access Journals (Sweden)

    Yolanda Garcìa Ruiz

    2016-12-01

    Full Text Available The economic crisis so strongly affecting some southern European countries has led to significant cuts in the system of universal public health care in Spain. Such measures particularly affect irregular immigrants and can also cause significant public health consequences. A form of civil resistance that deserves to be analyzed is the conscientious objection of Spanish doctors who have chosen to continue attending irregular immigrants in contravention of new the rules restricting their access to the public health system and their right to health. The aim of this paper is to analyze the new regulation which cut health care for irregular immigrants in Spain, the impact of this new regulation on the most vulnerable groups, and the response of doctors, who exercised their right to conscientious objection in relation to applying the new regulation. Finally to examine the announcement of change which came about as a consequence of international and domestic social pressure causing political risk to the Spanish National Government. La crisis económica, que ha afectado tan profundamente a algunos países del sur de Europa, ha dado lugar a significativos recortes en el sistema de atención sanitaria pública en España. Algunas de las medidas adoptadas han afectado específicamente a los inmigrantes irregulares y pueden tener, incluso, efectos en el ámbito de la salud pública. Una forma de desobediencia civil que merece ser analizada es la declaración de objeción de conciencia de determinados médicos y profesionales sanitarios españoles que han continuado atendiendo a los inmigrantes irregulares en contra de las nuevas  restricciones impuestas por el Gobierno que afectan al reconocimiento universal del derecho a la salud. El propósito de este artículo es el de analizar la nueva regulación que limita el acceso a la asistencia sanitaria de los inmigrantes irregulares en España, el impacto de esta nueva regulación en los grupos más vulnerables

  17. Simultaneous observations of ESF irregularities over Indian region using radar and GPS

    Directory of Open Access Journals (Sweden)

    S. Sripathi

    2008-10-01

    Full Text Available In this paper, we present simultaneous observations of temporal and spatial variability of total electron content (TEC and GPS amplitude scintillations on L1 frequency (1.575 GHz during the time of equatorial spread F (ESF while the MST radar (53 MHz located at Gadanki (13.5° N, 79.2° E, Dip latitude 6.3° N, a low latitude station, made simultaneous observations. In particular, the latitudinal and longitudinal extent of TEC and L-band scintillations was studied in the Indian region for different types of ESF structures observed using the MST radar during the low solar activity period of 2004 and 2005. Simultaneous radar and GPS observations during severe ESF events in the pre-midnight hour reveal that significant GPS L band scintillations, depletions in TEC, and the double derivative of the TEC index (DROTI, which is a measure of fluctuations in TEC, obtained at low latitudes coincide with the appearance of radar echoes at Gadanki. As expected, when the irregularities reach higher altitudes as seen in the radar map during pre-midnight periods, strong scintillations on an L-band signal are observed at higher latitudes. Conversely, when radar echoes are confined to only lower altitudes, weak scintillations are found and their latitudinal extent is small. During magnetically quiet periods, we have recorded plume type radar echoes during a post-midnight period that is devoid of L-band scintillations. Using spectral slopes and cross-correlation index of the VHF scintillation observations, we suggest that these irregularities could be "dead" or "fossil" bubbles which are just drifting in from west. This scenario is consistent with the observations where suppression of pre-reversal enhancement (PRE in the eastward electric field is indicated by ionosonde observations of the height of equatorial F layer and also occurrence of low spectral width in the radar observations relative to pre-midnight period. However, absence of L-band scintillations during

  18. Frequency and irregularity of heart rate in drivers suspected of driving under the influence of cannabis.

    Science.gov (United States)

    Khiabani, Hassan Z; Mørland, Jørg; Bramness, Jørgen G

    2008-12-01

    Delta 9-tetrahydrocannabinol (THC) is the major active component of cannabis. Cardiovascular effects of THC have previously been reported: tachycardia after intake, but also bradycardia at higher doses. The purpose of this study was, firstly, to investigate the frequency and irregularity of heart rate in a group of cannabis users in their natural surroundings. We also compared THC-positive drivers with a regular pulse with THC-positive drivers with an irregular pulse. The division of Forensic Toxicology and Drug Abuse (DFTDA) at the Norwegian Institute of Public Heath analyzes blood samples from all drivers suspected of driving under the influence of drugs. We studied pulse rate and regularity in 502 THC-positive drivers who tested negative for other substances. As a control group, we randomly selected 125 drug-negative cases from the database of the DFTDA; no alcohol, narcotics, or medicinal drugs of abuse were detected. The Delta9-THC-positive drivers had a higher mean pulse rate than the control group [82.8 beats/min (SD 16.3) versus 75.6 beats/min (SD 9.2)] and more cases with tachycardia were detected in the Delta9-THC-positive group (19.4% versus 1.6%). There was only one driver with an irregular heart beat in the control group, while there were nine among the Delta9-THC-positive drivers. The drivers with an irregular pulse were over-represented amongst those with the lowest blood Delta9-THC concentrations. This report represents a large study of subjects in a real-life situation and includes observations on pulse frequency, regularity, and blood Delta9-THC concentration. A substantial fraction of Delta9-THC-positive drivers had tachycardia, but there was no correlation between blood Delta9-THC concentration and pulse rate in the present study. We had no further diagnostic information on the cause of the pulse irregularities, but our results indicate that occasional users of cannabis tend to have irregular heart rates at low THC concentrations and at low

  19. Understanding uncertainty

    CERN Document Server

    Lindley, Dennis V

    2013-01-01

    Praise for the First Edition ""...a reference for everyone who is interested in knowing and handling uncertainty.""-Journal of Applied Statistics The critically acclaimed First Edition of Understanding Uncertainty provided a study of uncertainty addressed to scholars in all fields, showing that uncertainty could be measured by probability, and that probability obeyed three basic rules that enabled uncertainty to be handled sensibly in everyday life. These ideas were extended to embrace the scientific method and to show how decisions, containing an uncertain element, could be rationally made.

  20. Understanding analysis

    CERN Document Server

    Abbott, Stephen

    2015-01-01

    This lively introductory text exposes the student to the rewards of a rigorous study of functions of a real variable. In each chapter, informal discussions of questions that give analysis its inherent fascination are followed by precise, but not overly formal, developments of the techniques needed to make sense of them. By focusing on the unifying themes of approximation and the resolution of paradoxes that arise in the transition from the finite to the infinite, the text turns what could be a daunting cascade of definitions and theorems into a coherent and engaging progression of ideas. Acutely aware of the need for rigor, the student is much better prepared to understand what constitutes a proper mathematical proof and how to write one. Fifteen years of classroom experience with the first edition of Understanding Analysis have solidified and refined the central narrative of the second edition. Roughly 150 new exercises join a selection of the best exercises from the first edition, and three more project-sty...

  1. Understanding ayurveda.

    Science.gov (United States)

    Gadgil, Vaidya Dilip

    2010-01-01

    Ayurveda needs to achieve its full potential both in India and globally. This requires imparting to its students full appreciation of Ayurveda's power and strength, particularly proper understanding of the advantages of applying it to treat chronic and acute diseases. To this end, we explain the necessity of learning Sanskrit as a medium of study, and the advantages of learning the Texts in the traditional way, rather than relying on translations with all the loss of meaning and precision, which that entails. We emphasize the use of Triskandhakosha as a means to fully understand Ayurveda fundamental concepts and technical terms, so that all their shades of meaning are fully understood, and all their usages given in different places in the texts. Only by such methods can full appreciation of Ayurvedic wisdom be achieved, and the full depth and power of its knowledge be applied. Only then will its true status among systems of medicine come to be appreciated, either in India or more widely in the world as a whole.

  2. Understanding Ayurveda

    Directory of Open Access Journals (Sweden)

    Vaidya Dilip Gadgil

    2010-01-01

    Full Text Available Ayurveda needs to achieve its full potential both in India and globally. This requires imparting to its students full appreciation of Ayurveda′s power and strength, particularly proper understanding of the advantages of applying it to treat chronic and acute diseases. To this end, we explain the necessity of learning Sanskrit as a medium of study, and the advantages of learning the Texts in the traditional way, rather than relying on translations with all the loss of meaning and precision, which that entails. We emphasize the use of Triskandhakosha as a means to fully understand Ayurveda fundamental concepts and technical terms, so that all their shades of meaning are fully understood, and all their usages given in different places in the texts. Only by such methods can full appreciation of Ayurvedic wisdom be achieved, and the full depth and power of its knowledge be applied. Only then will its true status among systems of medicine come to be appreciated, either in India or more widely in the world as a whole.

  3. Irregular Firing and High-Conductance States in Spinal Motoneurons during Scratching and Swimming

    DEFF Research Database (Denmark)

    Guzulaitis, Robertas; Hounsgaard, Jorn; Alaburda, Aidas

    2016-01-01

    UNLABELLED: Intense synaptic transmission during scratch network activity increases conductance and induces irregular firing in spinal motoneurons. It is not known whether this high-conductance state is a select feature for scratching or a property that goes with spinal motor network activity...... in general. Here we compare conductance and firing patterns in spinal motoneurons during network activity for scratching and swimming in an ex vivo carapace-spinal cord preparation from adult turtles (Trachemys scripta elegans). The pattern and relative engagement of motoneurons are distinctly different...... in scratching and swimming. Nevertheless, we found increased synaptic fluctuations in membrane potential, irregular firing, and increased conductance in spinal motoneurons during scratch and swim network activity. Our finding indicates that intense synaptic activation of motoneurons is a general feature...

  4. Provision of health services to irregular migrants with a special focus on children.

    Science.gov (United States)

    Søvig, Karl Harald

    2011-01-01

    All European countries are now facing a situation where a part of the population consists of migrants without a permit to stay or reside. These persons may have health problems, and the question then rises regarding health services to irregular migrants. Normally, welfare benefits are offered those with a relationship to the country concerned, as citizen, asylum seeker, tourist, etc. Irregular migrants are outside the society, and it could be suggested that they therefore should be denied health services. On the other hand, common European standards of humanity lay obligations on the States, for example, where situations are life-threatening. This contribution gives an overview of relevant legal instruments, both from the UN, Council of Europe and the European Union. Although there are many similarities, the instruments have their differences, and there may even be some tensions regarding the underlying values.

  5. Identifying irregularly shaped crime hot-spots using a multiobjective evolutionary algorithm

    Science.gov (United States)

    Wu, Xiaolan; Grubesic, Tony H.

    2010-12-01

    Spatial cluster detection techniques are widely used in criminology, geography, epidemiology, and other fields. In particular, spatial scan statistics are popular and efficient techniques for detecting areas of elevated crime or disease events. The majority of spatial scan approaches attempt to delineate geographic zones by evaluating the significance of clusters using likelihood ratio statistics tested with the Poisson distribution. While this can be effective, many scan statistics give preference to circular clusters, diminishing their ability to identify elongated and/or irregular shaped clusters. Although adjusting the shape of the scan window can mitigate some of these problems, both the significance of irregular clusters and their spatial structure must be accounted for in a meaningful way. This paper utilizes a multiobjective evolutionary algorithm to find clusters with maximum significance while quantitatively tracking their geographic structure. Crime data for the city of Cincinnati are utilized to demonstrate the advantages of the new approach and highlight its benefits versus more traditional scan statistics.

  6. The phase curve survey of the irregular saturnian satellites: A possible method of physical classification

    Science.gov (United States)

    Bauer, James M.; Grav, Tommy; Buratti, Bonnie J.; Hicks, Michael D.

    2006-09-01

    During its 2005 January opposition, the saturnian system could be viewed at an unusually low phase angle. We surveyed a subset of Saturn's irregular satellites to obtain their true opposition magnitudes, or nearly so, down to phase angle values of 0.01°. Combining our data taken at the Palomar 200-inch and Cerro Tololo Inter-American Observatory's 4-m Blanco telescope with those in the literature, we present the first phase curves for nearly half the irregular satellites originally reported by Gladman et al. [2001. Nature 412, 163-166], including Paaliaq (SXX), Siarnaq (SXXIX), Tarvos (SXXI), Ijiraq (SXXII), Albiorix (SXVI), and additionally Phoebe's narrowest angle brightness measured to date. We find centaur-like steepness in the phase curves or opposition surges in most cases with the notable exception of three, Albiorix and Tarvos, which are suspected to be of similar origin based on dynamical arguments, and Siarnaq.

  7. The influence of rail surface irregularities on contact forces and local stresses

    Science.gov (United States)

    Andersson, Robin; Torstensson, Peter T.; Kabo, Elena; Larsson, Fredrik

    2015-01-01

    The effect of initial rail surface irregularities on promoting further surface degradation is investigated. The study concerns rolling contact fatigue formation, in particular in the form of the so-called squats. The impact of surface irregularities in the form of dimples is quantified by peak magnitudes of dynamic contact stresses and contact forces. To this end simulations of two-dimensional (later extended to three-dimensional) vertical dynamic vehicle-track interaction are employed. The most influencing parameters are identified. It is shown that even very shallow dimples might have a large impact on local contact stresses. Peak magnitudes of contact forces and stresses due to the influence of rail dimples are shown to exceed those due to rail corrugation.

  8. Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

    International Nuclear Information System (INIS)

    Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du

    2015-01-01

    Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

  9. Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du [NDE Performance Demonstration Team, Korea Hydro and Nuclear Power, Central Research Institute, Daejeon (Korea, Republic of)

    2015-02-15

    Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

  10. Serbian migration policy concerning irregular migration and asylum in the context of the EU integration process

    Directory of Open Access Journals (Sweden)

    Marta Stojić-Mitrović

    2016-02-01

    Full Text Available In this paper I would like to present Serbian migration policy concerning irregular migration and asylum in the context of the attempts of the Serbian state to become a member of the European Union. I would describe the history of the asylum system prior and after the implementation of the independent asylum system in Serbia in 2008. My presentation of the Serbian migration policy would be channelled by the analysis of some particular political issues, such as the externalization of the EU borders’ control, as well as some relevant elements of the European integration process, like visa liberalization. The second, more culturally specific dimension of the issue would be accessed through the demonstration of both legislative and public conceptualizations of the irregular migrants, asylum seekers and refugees in Serbia.

  11. CORPORATE GOVERNANCE AND ACCOUNTING IRREGULARITIES: Evidence from the Two-tiered Board Structure in Indonesia

    Directory of Open Access Journals (Sweden)

    Jaswadi JASWADI

    2012-09-01

    Full Text Available This study aims to investigate the extent to which the Indonesian corporate governance mechanism acts as an effective tool for protecting financial statements users against accounting irregularities. Considering that accounting irregularities might occur in between error and the fraud act, this study reviews the literature on minimizing the seriousness of these reporting incidences. The level of seriousness in misstatements is more severe when: (1 there is absence of financial expert(s on supervisory boards and audit committees, (2 companies have short tenured-CEOs and poor internal control systems, and (3 auditors are solely appointed by firms’ BOCs without agreement of block holders (known as referral. In addition, an examination of simultaneous effects of each corporate governance dimension reveals a general weakness of the BOCs and their audit committees. However, the BOC and audit committee could be an effective tool in mitigating reporting incidences, especially when they show high-quality collaboration.

  12. Characterization of Nightside Mid-latitude Irregularities Observed with the Blackstone SuperDARN Radar

    Science.gov (United States)

    Ruohoniemi, J. M.; Ribeiro, A. J.; Baker, J. B.; Greenwald, R. A.; Newell, P. T.

    2009-12-01

    The new mid-latitude SuperDARN radars at Wallops Island and Blackstone observe strong coherent backscattering on an almost nightly basis from latitudes that appear to be subauroral. One study has demonstrated an excellent correlation with the occurrence of density and temperature gradients within the ionospheric projection of the plasmapause (Greenwald et al., Geophys. Res. Lett. [2006]). We have processed all the data collected with the Blackstone radar since its inception in February 2008 for a characterization of the occurrence and properties of ‘plasmapause’ scatter. We have determined the local time and Kp dependencies of the activity and the relation of the spatial distribution of the irregularities to magnetospheric boundaries and ionospheric density gradients. We establish that the irregularities are a feature of the quiet-time subauroral ionosphere and provide a valuable diagnostic of the electric fields in the inner magnetosphere.

  13. Mei symmetry and conservation laws of discrete nonholonomic dynamical systems with regular and irregular lattices

    International Nuclear Information System (INIS)

    Zhao Gang-Ling; Chen Li-Qun; Fu Jing-Li; Hong Fang-Yu

    2013-01-01

    In this paper, Noether symmetry and Mei symmetry of discrete nonholonomic dynamical systems with regular and the irregular lattices are investigated. Firstly, the equations of motion of discrete nonholonomic systems are introduced for regular and irregular lattices. Secondly, for cases of the two lattices, based on the invariance of the Hamiltomian functional under the infinitesimal transformation of time and generalized coordinates, we present the quasi-extremal equation, the discrete analogues of Noether identity, Noether theorems, and the Noether conservation laws of the systems. Thirdly, in cases of the two lattices, we study the Mei symmetry in which we give the discrete analogues of the criterion, the theorem, and the conservative laws of Mei symmetry for the systems. Finally, an example is discussed for the application of the results

  14. Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

    International Nuclear Information System (INIS)

    Sevastianov, L. A.; Egorov, A. A.; Sevastyanov, A. L.

    2013-01-01

    Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell’s equations is made to obey “inclined” boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of “entanglement” of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lüneburg lens.

  15. An Efficient Heuristic Approach for Irregular Cutting Stock Problem in Ship Building Industry

    Directory of Open Access Journals (Sweden)

    Yan-xin Xu

    2016-01-01

    Full Text Available This paper presents an efficient approach for solving a real two-dimensional irregular cutting stock problem in ship building industry. Cutting stock problem is a common cutting and packing problem that arises in a variety of industrial applications. A modification of selection heuristic Exact Fit is applied in our research. In the case referring to irregular shapes, a placement heuristics is more important to construct a complete solution. A placement heuristic relating to bottom-left-fill is presented. We evaluate the proposed approach using generated instance only with convex shapes in literatures and some instances with nonconvex shapes based on real problem from ship building industry. The results demonstrate that the effectiveness and efficiency of the proposed approach are significantly better than some conventional heuristics.

  16. Stability of a Bose Condensate in the presence of regular and irregular potentials

    International Nuclear Information System (INIS)

    Gunn, J.M.F.

    1984-05-01

    The stability of an interacting Bose Condensate in the presence of a periodic potential is discussed. The condensate is destroyed if the potential is sufficiently strong, for certain densities of particles. Secondly irregular potentials of two types are considered: a dilute set of ''defect'' potentials in an otherwise periodic potential; and a highly irregular potential. In the first case, if the defect potential is sufficiently strong, the condensate is found to have a depletion which varies with the concentration of the defects. In the latter case it is argued that the condensate is totally destroyed. The consequences of the theory for experiments on 4 He films are discussed, and some new experiments proposed. (author)

  17. An experimental study of irregular wave forces on multiple quasi-ellipse caissons

    Science.gov (United States)

    Ren, Xiaozhong; Zhang, Peng; Ma, Yuxiang; Meng, Yufan

    2014-09-01

    An experimental investigation of irregular wave forces on quasi-ellipse caisson structures is presented. Irregular waves were generated based on the Jonswap spectrum with two significant wave heights, and the spectrum peak periods range from 1.19 s to 1.81 s. Incident wave directions relative to the centre line of the multiple caissons are from 0° to 22.5°. The spacing between caissons ranges from 2 to 3 times that of the width of the caisson. The effects of these parameters on the wave forces of both the perforated and non-perforated caissons were compared and analyzed. It was found that the perforated caisson can reduce wave forces, especially in the transverse direction. Furthermore, the relative interval and incident wave direction have significant effects on the wave forces in the case of multiple caissons.

  18. Time-Scale and Time-Frequency Analyses of Irregularly Sampled Astronomical Time Series

    Directory of Open Access Journals (Sweden)

    S. Roques

    2005-09-01

    Full Text Available We evaluate the quality of spectral restoration in the case of irregular sampled signals in astronomy. We study in details a time-scale method leading to a global wavelet spectrum comparable to the Fourier period, and a time-frequency matching pursuit allowing us to identify the frequencies and to control the error propagation. In both cases, the signals are first resampled with a linear interpolation. Both results are compared with those obtained using Lomb's periodogram and using the weighted waveletZ-transform developed in astronomy for unevenly sampled variable stars observations. These approaches are applied to simulations and to light variations of four variable stars. This leads to the conclusion that the matching pursuit is more efficient for recovering the spectral contents of a pulsating star, even with a preliminary resampling. In particular, the results are almost independent of the quality of the initial irregular sampling.

  19. A research about characteristics of longitudinal variations of ES layers irregularities based on CHAMP occultation measurements

    Science.gov (United States)

    Liao, Sunmin

    2018-04-01

    Based on the data of CHAMP occultation measurements, this paper makes a preliminary analysis of the longitudinal variations of ES irregular structure by using Fourier decomposition and reconstruction technique. It is found that the longitudinal variations of the ES irregular structure show the features of multiple wave-numbers, which is dominated by the wave number 1 to the wave number 5 components, and decrease from the amplitudes of the wave number 6 components. The features of wave number structures are very different in different DIP latitude and different seasons. The number of crests in summer and autumn is mostly 3 or 4 crest structures, while the number of crests in spring achieves 5 at DIP 15°N with small fluctuates, the crests number of winter is the least. In the multiple wave-numbers structure, the wave number 4 component shows a significant dependence on the season, mainly in the summer and autumn, particularly obvious from July to October.

  20. Irregular Polyomino-Shaped Subarrays for Space-Based Active Arrays

    Directory of Open Access Journals (Sweden)

    R. J. Mailloux

    2009-01-01

    Full Text Available This paper presents new results showing the application of polyomino-based subarrays to limited field of view and wideband, wide-angle scanning. This technology can reduce the number of phase controls in arrays used for limited sector coverage or the number of time delay devices for wideband radar or communications, and so can reduce the cost of space-based active arrays. We concentrate on the wideband application. Results are presented by comparing the gain and peak sidelobe results of irregular polyomino subarray-based arrays with those of rectangular subarrays. It is shown that using irregular polyomino subarrays can result in a major decrease in sidelobes while presenting, in most cases, only a few tenths of a dB gain reduction compared to rectangular subarrays.

  1. A Hybrid Model Based on Wavelet Decomposition-Reconstruction in Track Irregularity State Forecasting

    Directory of Open Access Journals (Sweden)

    Chaolong Jia

    2015-01-01

    Full Text Available Wavelet is able to adapt to the requirements of time-frequency signal analysis automatically and can focus on any details of the signal and then decompose the function into the representation of a series of simple basis functions. It is of theoretical and practical significance. Therefore, this paper does subdivision on track irregularity time series based on the idea of wavelet decomposition-reconstruction and tries to find the best fitting forecast model of detail signal and approximate signal obtained through track irregularity time series wavelet decomposition, respectively. On this ideology, piecewise gray-ARMA recursive based on wavelet decomposition and reconstruction (PG-ARMARWDR and piecewise ANN-ARMA recursive based on wavelet decomposition and reconstruction (PANN-ARMARWDR models are proposed. Comparison and analysis of two models have shown that both these models can achieve higher accuracy.

  2. Irregular or absent periods--what can an ultrasound scan tell you?

    Science.gov (United States)

    Khalid, Asma

    2004-02-01

    Transvaginal ultrasonography has increased our appreciation of the physiological changes in the ovary and endometrium that occur during the normal menstrual cycle. It has become a primary investigative tool in women with irregular or absent periods. Its usefulness in cases of primary amenorrhoea to assess anatomy is also undisputed although it may have limitations in terms of its specificity. However, the interpretation of ultrasound images in women with irregular menses or secondary amenorrhoea is not entirely straightforward. This is particularly true in the diagnosis of polycystic ovary syndrome, a condition of uncertain aetiology, which may present with oligoamenorrhoea. This chapter aims to discuss the benefits and limitations of ultrasound while taking into account the broad overlap between normal and abnormal physiology, some of which has still to be elucidated.

  3. Finite Length Analysis of Irregular Repetition Slotted ALOHA in the Waterfall Region

    OpenAIRE

    Amat, Alexandre Graell i; Liva, Gianluigi

    2018-01-01

    A finite length analysis is introduced for irregular repetition slotted ALOHA (IRSA) that enables to accurately estimate its performance in the moderate-to-high packet loss probability regime, i.e., in the so-called waterfall region. The analysis is tailored to the collision channel model, which enables mapping the description of the successive interference cancellation process onto the iterative erasure decoding of low-density parity-check codes. The analysis provides accurate estimates of t...

  4. Development of Computer Program for Analysis of Irregular Non Homogenous Radiation Shielding

    International Nuclear Information System (INIS)

    Bang Rozali; Nina Kusumah; Hendro Tjahjono; Darlis

    2003-01-01

    A computer program for radiation shielding analysis has been developed to obtain radiation attenuation calculation in non-homogenous radiation shielding and irregular geometry. By determining radiation source strength, geometrical shape of radiation source, location, dimension and geometrical shape of radiation shielding, radiation level of a point at certain position from radiation source can be calculated. By using a computer program, calculation result of radiation distribution analysis can be obtained for some analytical points simultaneously. (author)

  5. Report on the HAARP 2008 Winter Campaign Focusing on Artificial Ionospheric Irregularities

    Science.gov (United States)

    2008-07-31

    Figure Bl. Magnetic field variations recorded by the fluxgate magnetometer 30 Figure B2. Composite ionogram showing the variation of the reflection...variation was monitored by the Fluxgate Magnetometer . The density irregularities were monitored by the Ionosonde. 20:00 Preliminary Results The...magnetic field variations in three directions (H, D, and Z) recorded by the fluxgate magnetometer from UTC 20:00 to 04:00 are shown in the plots of

  6. Direct solution of the biharmonic equation on rectangular regions and the Poisson equation on irregular regions

    International Nuclear Information System (INIS)

    Buzbee, B.L.; Dorr, F.W.

    1974-01-01

    The discrete biharmonic equation on a rectangular region and the discrete Poisson equation on an irregular region can be treated as modifications to matrix problems with very special structure. It is shown how to use the direct method of matrix decomposition to formulate an effective numerical algorithm for these problems. For typical applications the operation count is O(N 3 ) for an N x N grid. Numerical comparisons with other techniques are included. (U.S.)

  7. Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease

    DEFF Research Database (Denmark)

    Rose, Martin Høyer; Løkkegaard, Annemette; Sonne-Holm, Stig

    2013-01-01

    with idiopathic PD and 15 neurologically healthy matched controls performed isometric maximal contractions (extension/flexion) as well as steady submaximal and powerful isometric knee extensions. The patients with PD showed decreased isometric tremor irregularity. Torque steadiness was reduced in PD...... that both knee isometric tremor Approximate Entropy and torque steadiness clearly differentiate between patients with PD and healthy controls. Furthermore, severely compromised RFD was found in patients with PD and was associated with decreased agonist muscle activation....

  8. Characteristics and sources of the electron density irregularities in the mid latitude E and Fregions

    Science.gov (United States)

    2017-05-10

    and has since been monitoring the occurrence of field-aligned irregularities ( FAIs ) in the northern middle latitudes. We investigated the...characteristics and occurrence climatology of the FAIs in the middle latitude E- and F-region ionosphere using the Daejeon VHF radar data. Depending on the...sunset and post-sunrise periods. The F-region FAIs in the mid-latitude are bounded to occur during the nighttime between local sunset and sunrise [J

  9. F region electron density irregularity spectra near Auroral acceleration and shear regions

    International Nuclear Information System (INIS)

    Basu, S.; Basu, S.; MacKenzie, E.; Coley, W.R.; Hanson, W.B.; Lin, C.S.

    1984-01-01

    Spectral characteristics of auroral F region irregularities were studied by the use of high-resolution (approx.35 m) density measurements made by the retarding potential analyzer (RPA) on board the Atmosphere Explorer D (AE-D) satellite during two orbits when the satellite was traversing the high-latitude ionosphere in the evening sector. Coordinated DMSP passes provided synoptic coverage of auroral activity. The auroral energy input was estimated by intergrating the low-energy electron (LEE) data on AE-D. It was found that the one-dimensional in situ spectral index (p 1 ) of the irregularities at scale lengths of 1 values of approx.-3. This is interpreted as resulting from the effects of E region conductivity on the F region irregularity structure. The regions in between the precipitation structures, where presumably the E region conductivity was small, were generally associated with large shears in the horizontal E-W drifts and large velocities, as measured by the ion drift meter on board AE-D. The maximum drifts measured were approx.2 km s -1 , corresponding to an electric field of 100 mV m -1 . The large-velocity regions were also associated with substantial ion heating and electron density depletions. The largest shear magnitudes observed were approx.80 m s -1 km -1 , and the shear gradient scale lengths were approx.10 km, which was approximately the resolution of the ion drift meter data set used. The spectral characteristics of irregularities in the large, variable flow regions were very different, with p 1 being approx.-1

  10. Penalized likelihood and multi-objective spatial scans for the detection and inference of irregular clusters

    Directory of Open Access Journals (Sweden)

    Fonseca Carlos M

    2010-10-01

    Full Text Available Abstract Background Irregularly shaped spatial clusters are difficult to delineate. A cluster found by an algorithm often spreads through large portions of the map, impacting its geographical meaning. Penalized likelihood methods for Kulldorff's spatial scan statistics have been used to control the excessive freedom of the shape of clusters. Penalty functions based on cluster geometry and non-connectivity have been proposed recently. Another approach involves the use of a multi-objective algorithm to maximize two objectives: the spatial scan statistics and the geometric penalty function. Results & Discussion We present a novel scan statistic algorithm employing a function based on the graph topology to penalize the presence of under-populated disconnection nodes in candidate clusters, the disconnection nodes cohesion function. A disconnection node is defined as a region within a cluster, such that its removal disconnects the cluster. By applying this function, the most geographically meaningful clusters are sifted through the immense set of possible irregularly shaped candidate cluster solutions. To evaluate the statistical significance of solutions for multi-objective scans, a statistical approach based on the concept of attainment function is used. In this paper we compared different penalized likelihoods employing the geometric and non-connectivity regularity functions and the novel disconnection nodes cohesion function. We also build multi-objective scans using those three functions and compare them with the previous penalized likelihood scans. An application is presented using comprehensive state-wide data for Chagas' disease in puerperal women in Minas Gerais state, Brazil. Conclusions We show that, compared to the other single-objective algorithms, multi-objective scans present better performance, regarding power, sensitivity and positive predicted value. The multi-objective non-connectivity scan is faster and better suited for the

  11. Measurements of linear attenuation coefficients of irregular shaped samples by two media method

    International Nuclear Information System (INIS)

    Singh, Sukhpal; Kumar, Ashok; Thind, Kulwant Singh; Mudahar, Gurmel S.

    2008-01-01

    The linear attenuation coefficient values of regular and irregular shaped flyash materials have been measured without knowing the thickness of a sample using a new technique namely 'two media method'. These values have also been measured with a standard gamma ray transmission method and obtained theoretically with winXCOM computer code. From the comparison it is reported that the two media method has given accurate results of attenuation coefficients of flyash materials

  12. Very high latitude F-region irregularities observed by HF-radar backscatter

    International Nuclear Information System (INIS)

    Baker, K.B.; Greenwald, R.A.; Tsunoda, R.T.

    1983-01-01

    In February and March, 1982, a coherent scatter HF radar was operated from Cleary, Alaska to observe 7- to 15-m wavelength F-region plasma irregularities near the poleward edge of the auroral zone and in the polar cap. The radar operated for five days from February 25 to March 1 and produced approximately 700,000 Doppler spectra during that time. Of those nearly 700,000 spectra, approximately 10% showed backscattered power 3 dB or more above the noise level. A ray tracing technique using electron densities determined by the Chatanika incoherent scatter radar was used to predict locations where the HF waves were approximately normal to the magnetic field. If those locations were also to contain small scale electron density structure, then one would expect them to backscatter the HF waves. Several comparisons were made between predicted and observed locations of radiowave backscatter and excellent agreement was obtained. In addition, comparisons of the Doppler velocities observed by the coherent scatter HF radar and those observed by the Chatanika radar showed good agreement, suggesting that the plasma irregularities observed by the HF radar drift with the ambient plasma. In addition, average vector velocities calculated for the entire 5-day period show a flow pattern consistent with polar cap convection models. This again indicates that the irregularities drift with the plasma, as is predicted by a number of theories of F-region plasma irregularities. In the summer of 1983, the research program begun with those measurements will be continued with a steerable phased-array HF radar located at Goose Bay, Labrador, that will view the same ionospheric region as does the Sondre Stromfjord incoherent scatter radar

  13. Exploring Hardware Support For Scaling Irregular Applications on Multi-node Multi-core Architectures

    Energy Technology Data Exchange (ETDEWEB)

    Secchi, Simone; Ceriani, Marco; Tumeo, Antonino; Villa, Oreste; Palermo, Gianluca; Raffo, Luigi

    2013-06-05

    With the recent emergence of large-scale knowledge dis- covery, data mining and social network analysis, irregular applications have gained renewed interest. Classic cache-based high-performance architectures do not provide optimal performances with such kind of workloads, mainly due to the very low spatial and temporal locality of the irregular control and memory access patterns. In this paper, we present a multi-node, multi-core, fine-grained multi-threaded shared-memory system architecture specifically designed for the execution of large-scale irregular applications, and built on top of three pillars, that we believe are fundamental to support these workloads. First, we offer transparent hardware support for Partitioned Global Address Space (PGAS) to provide a large globally-shared address space with no software library overhead. Second, we employ multi-threaded multi-core processing nodes to achieve the necessary latency tolerance required by accessing global memory, which potentially resides in a remote node. Finally, we devise hardware support for inter-thread synchronization on the whole global address space. We first model the performances by using an analytical model that takes into account the main architecture and application characteristics. We describe the hardware design of the proposed cus- tom architectural building blocks that provide support for the above- mentioned three pillars. Finally, we present a limited-scale evaluation of the system on a multi-board FPGA prototype with typical irregular kernels and benchmarks. The experimental evaluation demonstrates the architecture performance scalability for different configurations of the whole system.

  14. Zonal drifts of ionospheric irregularities at temperate latitude in the Indian region

    Directory of Open Access Journals (Sweden)

    S. Kumar

    1995-07-01

    Full Text Available The systematic time differences observed in the onset of postsunset VHF scintillations recorded simultaneously at Ujjain (Geogr. lat. 23.2°N, Geogr. long. 75.6°E and Bhopal (Geogr. lat. 23.2°N, Geogr. long. 77.6°E, situated at the peak of the anomaly crest in the Indian region, have been analysed to determine the zonal drifts of scintillation-producing irregularities. The method is based on the assumption that the horizontal movement of irregularities does not change while crossing the F-region cross-over points of these stations. The calculated velocities of irregularities indicate an eastward drift decreasing from about 180 m s–1 to 55 m s–1 during the course of night. In the premidnight period, the drifts are reduced under the magnetically disturbed conditions. The average east-west extension of irregularites is found to be in the range of 200–500 km.

  15. MPPT-Based Control Algorithm for PV System Using iteration-PSO under Irregular shadow Conditions

    Directory of Open Access Journals (Sweden)

    M. Abdulkadir

    2017-02-01

    Full Text Available The conventional maximum power point tracking (MPPT techniques can hardly track the global maximum power point (GMPP because the power-voltage characteristics of photovoltaic (PV exhibit multiple local peaks in irregular shadow, and therefore easily fall into the local maximum power point. These conditions make it very challenging, and to tackle this deficiency, an efficient Iteration Particle Swarm Optimization (IPSO has been developed to improve the quality of solution and convergence speed of the traditional PSO, so that it can effectively track the GMPP under irregular shadow conditions. This proposed technique has such advantages as simple structure, fast response and strong robustness, and convenient implementation. It is applied to MPPT control of PV system in irregular shadow to solve the problem of multi-peak optimization in partial shadow. In order to verify the rationality of the proposed algorithm, however, recently the dynamic MPPT performance under varying irradiance conditions has been given utmost attention to the PV society. As the European standard EN 50530 which defines the recommended varying irradiance profiles, was released lately, the corresponding researchers have been required to improve the dynamic MPPT performance. This paper tried to evaluate the dynamic MPPT performance using EN 50530 standard. The simulation results show that iterative-PSO method can fast track the global MPP, increase tracking speed and higher dynamic MPPT efficiency under EN 50530 than the conventional PSO.

  16. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Science.gov (United States)

    Zuluaga-Ramírez, Pablo; Frövel, Malte; Belenguer, Tomás; Salazar, Félix

    2015-01-01

    This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL) and realistic variable amplitude loads (VAL), representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications. PMID:28793655

  17. Wireless sensing without sensors—an experimental study of motion/intrusion detection using RF irregularity

    International Nuclear Information System (INIS)

    Lee, Pius W Q; Tan, Hwee-Pink; Seah, Winston K G; Yao, Zexi

    2010-01-01

    Motion and intrusion detection are often cited as wireless sensor network (WSN) applications with typical configurations comprising clusters of wireless nodes equipped with motion sensors to detect human motion. Currently, WSN performance is subjected to several constraints, namely radio irregularity and finite on-board computation/energy resources. Radio irregularity in radio frequency (RF) propagation rises to a higher level in the presence of human activity due to the absorption effect of the human body. In this paper, we investigate the feasibility of monitoring RF transmission for the purpose of intrusion detection through experimentation. With empirical data obtained from the Crossbow TelosB platform in several different environments, the impact of human activity on the signal strength of RF signals in a WSN is evaluated. We then propose a novel approach to intrusion detection by turning a constraint in WSN, namely radio irregularity, into an advantage for the purpose of intrusion detection, using signal fluctuations to detect the presence of human activity within the WSN. Unlike RF fingerprinting, the 'intruders' here neither transmit nor receive any RF signals. By enabling existing wireless infrastructures to serve as intrusion detectors instead of deploying numerous costly sensors, this approach shows great promise for providing novel solutions

  18. Validation of AEGIS/SCOPE2 system through actual core follow calculations with irregular operational conditions

    International Nuclear Information System (INIS)

    Tabuchi, M.; Tatsumi, M.; Ohoka, Y.; Nagano, H.; Ishizaki, K.

    2017-01-01

    This paper describes overview of AEGIS/SCOPE2 system, an advanced in-core fuel management system for pressurized water reactors, and its validation results of actual core follow calculations including irregular operational conditions. AEGIS and SCOPE2 codes adopt more detailed and accurate calculation models compared to the current core design codes while computational cost is minimized with various techniques on numerical and computational algorithms. Verification and validation of AEGIS/SCOPE2 has been intensively performed to confirm validity of the system. As a part of the validation, core follow calculations have been carried out mainly for typical operational conditions. After the Fukushima Daiichi nuclear power plant accident, however, all the nuclear reactors in Japan suffered from long suspension and irregular operational conditions. In such situations, measured data in the restart and operation of the reactors should be good examinations for validation of the codes. Therefore, core follow calculations were carried out with AEGIS/SCOPE2 for various cases including zero power reactor physics tests with irregular operational conditions. Comparisons between measured data and predictions by AEGIS/SCOPE2 revealed the validity and robustness of the system. (author)

  19. Transformation-cost time-series method for analyzing irregularly sampled data.

    Science.gov (United States)

    Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G Baris; Kurths, Jürgen

    2015-06-01

    Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations-with associated costs-to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

  20. Electromagnetic waves in irregular multilayered spheroidal structures of finite conductivity: full wave solutions

    International Nuclear Information System (INIS)

    Bahar, E.

    1976-01-01

    The propagation of electromagnetic waves excited by electric dipoles oriented along the axis of multilayered spheroidal structures of finite conductivity is investigated. The electromagnetic parameters and the thickness of the layers of the structure are assumed to be functions of the latitude. In the analysis, electric and magnetic field transforms that constitute a discrete and a continuous spectrum of spherical waves are used to provide a suitable basis for the expansion of the electromagnetic fields at any point in the irregular spheroidal structure. For spheroidal structures with good conducting cores, the terms in the solutions associated with the continuous part of the wave spectrum vanish. In general, however, when the skin depth for the core is large compared to its dimensions or when the sources are located in the core of the structure and propagation in the core is of special interest, the contribution from the continuous part of the wave spectrum cannot be neglected. At each interface between the layers of the irregular spheroidal structure, exact boundary conditions are imposed. Since the terms of the field expansions in the irregular structure do not individually satisfy the boundary conditions, Maxwell's equations are reduced to sets of coupled ordinary first-order differential equations for the wave amplitudes. The solutions are shown to satisfy the reciprocity relationships in electromagnetic theory. The analysis may be applied to problems of radio wave propagation in a nonuniform model of the earth-ionosphere waveguide, particularly when focusing effects at the antipodes are important

  1. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Directory of Open Access Journals (Sweden)

    Pablo Zuluaga-Ramírez

    2015-11-01

    Full Text Available This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL and realistic variable amplitude loads (VAL, representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications.

  2. Transformation-cost time-series method for analyzing irregularly sampled data

    Science.gov (United States)

    Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G. Baris; Kurths, Jürgen

    2015-06-01

    Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations—with associated costs—to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

  3. Rheological Modeling of Macro Viscous Flows of Granular Suspension of Regular and Irregular Particles

    Directory of Open Access Journals (Sweden)

    Anna Maria Pellegrino

    2017-12-01

    Full Text Available This paper refers to complex granular-fluid mixtures involved into geophysical flows, such as debris and hyper-concentrated flows. For such phenomena, the interstitial fluids play a role when they are in the viscous regime. Referring to experiments on granular-fluid mixture carried out with pressure imposed annular shear cell, we study the rheological behaviour of dense mixture involving both spheres and irregular-shaped particles. For the case of viscous suspensions with irregular grains, a significant scatter of data from the trend observed for mixtures with spherical particles was evident. In effect, the shape of the particles likely plays a fundamental role in the flow dynamics, and the constitutive laws proposed by the frictional theory for the spheres are no longer valid. Starting from the frictional approach successfully applied to suspension of spheres, we demonstrate that also in case of irregular particles the mixture rheology may be fully characterized by the two relationships involving friction coefficient µ and volume concentration Ф as a function of the dimensionless viscous number Iv. To this goal, we provided a new consistent general model, referring to the volume fraction law and friction law, which accounts for the particle shape. In this way, the fitting parameters reduce just to the static friction angle µ1, and the two parameters, k and fs related to the grain shape. The resulting general model may apply to steady fully developed flows of saturated granular fluid mixture in the viscous regime, no matter of granular characteristics.

  4. Assimilating irregularly spaced sparsely observed turbulent signals with hierarchical Bayesian reduced stochastic filters

    International Nuclear Information System (INIS)

    Brown, Kristen A.; Harlim, John

    2013-01-01

    In this paper, we consider a practical filtering approach for assimilating irregularly spaced, sparsely observed turbulent signals through a hierarchical Bayesian reduced stochastic filtering framework. The proposed hierarchical Bayesian approach consists of two steps, blending a data-driven interpolation scheme and the Mean Stochastic Model (MSM) filter. We examine the potential of using the deterministic piecewise linear interpolation scheme and the ordinary kriging scheme in interpolating irregularly spaced raw data to regularly spaced processed data and the importance of dynamical constraint (through MSM) in filtering the processed data on a numerically stiff state estimation problem. In particular, we test this approach on a two-layer quasi-geostrophic model in a two-dimensional domain with a small radius of deformation to mimic ocean turbulence. Our numerical results suggest that the dynamical constraint becomes important when the observation noise variance is large. Second, we find that the filtered estimates with ordinary kriging are superior to those with linear interpolation when observation networks are not too sparse; such robust results are found from numerical simulations with many randomly simulated irregularly spaced observation networks, various observation time intervals, and observation error variances. Third, when the observation network is very sparse, we find that both the kriging and linear interpolations are comparable

  5. A novel method of the image processing on irregular triangular meshes

    Science.gov (United States)

    Vishnyakov, Sergey; Pekhterev, Vitaliy; Sokolova, Elizaveta

    2018-04-01

    The paper describes a novel method of the image processing based on irregular triangular meshes implementation. The triangular mesh is adaptive to the image content, least mean square linear approximation is proposed for the basic interpolation within the triangle. It is proposed to use triangular numbers to simplify using of the local (barycentric) coordinates for the further analysis - triangular element of the initial irregular mesh is to be represented through the set of the four equilateral triangles. This allows to use fast and simple pixels indexing in local coordinates, e.g. "for" or "while" loops for access to the pixels. Moreover, representation proposed allows to use discrete cosine transform of the simple "rectangular" symmetric form without additional pixels reordering (as it is used for shape-adaptive DCT forms). Furthermore, this approach leads to the simple form of the wavelet transform on triangular mesh. The results of the method application are presented. It is shown that advantage of the method proposed is a combination of the flexibility of the image-adaptive irregular meshes with the simple form of the pixel indexing in local triangular coordinates and the using of the common forms of the discrete transforms for triangular meshes. Method described is proposed for the image compression, pattern recognition, image quality improvement, image search and indexing. It also may be used as a part of video coding (intra-frame or inter-frame coding, motion detection).

  6. Targeting overall equipment efficiency for small medium enterprises with irregular production system

    Science.gov (United States)

    Prasetyawan, Y.; Suef, M.; Claudia, L.; Handayani, F. D.

    2018-04-01

    Overall Equipment Effectiveness (OEE) is widely used to measure the maturity of a production system. The company will be considered as World Class Manufacturing if it reaches more than 85% value, with near perfect value for availability, performance and quality factor. This assessment is usually taken on industries with regular production times named shift system. A typical 8 hours shift system is used in OEE measurement and performance monitoring. There are few Small to Medium Enterprise (SME) perform regular production times with shift systems, others using irregular production systems. The irregular production time in the SME production system is used because of demand fluctuations. This paper shows a quantitative analysis as a part of manufacturing system design to achieve a specific value of OEE for SME with irregular production systems, for individual businesses as well as collective business systems (some companies use the same production facilities for several processes). The results of experiments on several companies are presented, as a basis for determining the technical strategy of achieving OEE values.

  7. Evaluation of simplified two source model for relative electron output factor of irregular block shape

    International Nuclear Information System (INIS)

    Lo, Y. E.; Yi, B. Y.; Ahn, S. D.; Kim, J. H.; Lee, S. W.; Choi, E. K.

    2002-01-01

    A practical calculation algorithm which calculates the relative output factor (ROF) for electron irregular shaped-field has been developed and evaluated the accuracy and the effectiveness of the algorithm by comparing the measurements and the calculation results for irregular fields used in clinic. The algorithm assumes that the electron dose can be express as sum of the primary source component and the scattered component from the shielding block. The primary source is assumed to have Gaussian distribution, while the scattered component follows the inverse square law. Depth and angular dependency of the primary and the scattered are ignored for maximizing the practicability by reducing the number of parameters for the algorithm. Electron dose can be calculated with three parameters such as, the effective source distance, the variance of primary source, and the scattering power of the block. The coefficients are obtained from the square shaped-block measurements and these are confirmed from the rectangular or irregular shaped-fields. The results showed less than 1.5% difference between the calculation and measurements. The algorithm is proved to be practical, since one can acquire the full parameters with minimum measurements and generates accurate results within the clinically acceptable range

  8. PERLINDUNGAN HUKUM BAGI IRREGULAR MIGRANT WORKERS INDONESIA DI KAWASAN ASIA TENGGARA (DALAM PERSPEKTIF HUKUM HAM INTERNASIONAL

    Directory of Open Access Journals (Sweden)

    Riri Anggriani

    2017-05-01

    Full Text Available The development of globalization that occurred has considerable impact for human life and for countries in Southeast Asia. One is the movement of people from one country to another, especially concerning the problem of economic migrants seeking employment or working in a country where they work especially irregular migrant workers. These irregular migrants are vulnerable to violations of their human rights. The issue is how the protection of the law is provided by the country of origin through Indonesian national law in countries that are the destination of Indonesian migrant workers in the Southeast Asian Region through the perspective of international human rights law. This research is legal research. The results of this study indicate that Indonesian migrant workers with the status of irregular migrant workers are workers who also have the same rights as other migrant workers or other citizens so that countries (especially countries in Southeast Asia have an obligation to acknowledge and Protect them wherever they may be or under any circumstances they experience as contained in the provisions of international human rights law, especially in the Convention on the Protection of the Rights of All Migrant Workers and their Families (CMW, 1990.

  9. A Bandwidth-Optimized Multi-Core Architecture for Irregular Applications

    Energy Technology Data Exchange (ETDEWEB)

    Secchi, Simone; Tumeo, Antonino; Villa, Oreste

    2012-05-31

    This paper presents an architecture template for next-generation high performance computing systems specifically targeted to irregular applications. We start our work by considering that future generation interconnection and memory bandwidth full-system numbers are expected to grow by a factor of 10. In order to keep up with such a communication capacity, while still resorting to fine-grained multithreading as the main way to tolerate unpredictable memory access latencies of irregular applications, we show how overall performance scaling can benefit from the multi-core paradigm. At the same time, we also show how such an architecture template must be coupled with specific techniques in order to optimize bandwidth utilization and achieve the maximum scalability. We propose a technique based on memory references aggregation, together with the related hardware implementation, as one of such optimization techniques. We explore the proposed architecture template by focusing on the Cray XMT architecture and, using a dedicated simulation infrastructure, validate the performance of our template with two typical irregular applications. Our experimental results prove the benefits provided by both the multi-core approach and the bandwidth optimization reference aggregation technique.

  10. Understanding physics

    CERN Document Server

    Cassidy, David; Rutherford, James

    2002-01-01

    Understanding Physics provides a thorough grounding in contemporary physics while placing physics into its social and historical context Based in large part on the highly respected Project Physics Course developed by two of the authors, it also integrates the results of recent pedagogical research The text thus - teaches about the basic phenomena in the physical world and the concepts developed to explain them - shows that science is a rational human endeavor with a long and continuing tradition, involving many different cultures and people - develops facility in critical thinking, reasoned argumentation, evaluation of evidence, mathematical modeling, and ethical values The treatment emphasizes not only what we know but also how we know it, why we believe it, and what effects that knowledge has - Why do we believe the Earth and planets revolve around the Sun? - Why do we believe that matter is made of atoms? - How do relativity theory and quantum mechanics alter our conception of Nature and in what ways do th...

  11. Understanding users

    DEFF Research Database (Denmark)

    Johannsen, Carl Gustav Viggo

    2014-01-01

    Segmentation of users can help libraries in the process of understanding user similarities and differences. Segmentation can also form the basis for selecting segments of target users and for developing tailored services for specific target segments. Several approaches and techniques have been...... tested in library contexts and the aim of this article is to identify the main approaches and to discuss their perspectives, including their strenghts and weaknesses in, especially, public library contexts. The purpose is also to prsent and discuss the results of a recent - 2014 - Danish library user...... segmentation project using computer-generated clusters. Compared to traditional marketing texts, this article also tries to identify user segments or images or metaphors by the library profession itself....

  12. The calculation of relative output factor and depth dose for irregular electron fields in water

    International Nuclear Information System (INIS)

    Dunscombe, Peter; McGhee, Peter; Chu, Terence

    1996-01-01

    Purpose: A technique, based on sector integration and interpolation, has been developed for the computation of both relative output factor and depth dose of irregular electron fields in water. The purpose of this study was to determine the minimum experimental data set required for the technique to yield results within accepted dosimetric tolerances. Materials and Methods: PC based software has been written to perform the calculations necessary to dosimetrically characterize irregular shaped electron fields. The field outline is entered via digitiser and the SSD and energy via the keyboard. The irregular field is segmented into sectors of specified angle (2 deg. was used for this study) and the radius of each sector computed. The central ray depth dose is reconstructed by summing the contributions from each sector deduced from calibration depth doses measured for circular fields. Relative output factors and depth doses at SSDs at which calibrations were not performed are found by interpolation. Calibration data were measured for circular fields from 2 to 9 cm diameter at 100, 105, 110, and 115 cm SSD. A clinical cut out can be characterized in less than 2 minutes including entry of the outline using this software. The performance of the technique was evaluated by comparing calculated relative output factors, surface dose and the locations of d 80 , d 50 and d 20 with experimental measurements on a variety of cut out shapes at 9 and 18 MeV. The calibration data set (derived from circular cut outs) was systematically reduced to identify the minimum required to yield an accuracy consistent with current recommendations. Results: The figure illustrates the ability of the technique to calculate the depth dose for an irregular field (shown in the insert). It was found that to achieve an accuracy of 2% in relative output factor and 2% or 2 mm (our criterion) in percentage depth dose, calibration data from five circular fields at the four SSDs spanning the range 100-115 cm

  13. Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde

    Directory of Open Access Journals (Sweden)

    D. V. Phanikumar

    2008-07-01

    Full Text Available In this paper, we present seasonal variation of E region field-aligned irregularities (FAIs observed using the Gadanki radar and compare them with the seasonal variation of Es observed from a nearby location SHAR. During daytime, FAIs occur maximum in summer and throughout the day, as compared to other seasons. During nighttime, FAIs occur equally in both summer and winter, and relatively less in equinoxes. Seasonal variations of Es (i.e. ftEs and fbEs show that the daytime activity is maximum in summer and the nighttime activity is maximum in equinoxes. No relation is found between FAIs occurrence/SNR and ftEs/fbEs. FAIs occurrence, however, is found to be related well with (ftEs−fbEs. This aspect is discussed in the light of the present understanding of the mid-latitude Es-FAIs relationship. The seasonal variations of FAIs observed at Gadanki are compared in detail with those of Piura, which show a significant difference in the daytime observations. The observed difference has been discussed considering the factors governing the generation of FAIs.

  14. Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde

    Directory of Open Access Journals (Sweden)

    D. V. Phanikumar

    2008-07-01

    Full Text Available In this paper, we present seasonal variation of E region field-aligned irregularities (FAIs observed using the Gadanki radar and compare them with the seasonal variation of Es observed from a nearby location SHAR. During daytime, FAIs occur maximum in summer and throughout the day, as compared to other seasons. During nighttime, FAIs occur equally in both summer and winter, and relatively less in equinoxes. Seasonal variations of Es (i.e. ftEs and fbEs show that the daytime activity is maximum in summer and the nighttime activity is maximum in equinoxes. No relation is found between FAIs occurrence/SNR and ftEs/fbEs. FAIs occurrence, however, is found to be related well with (ftEs−fbEs. This aspect is discussed in the light of the present understanding of the mid-latitude Es-FAIs relationship. The seasonal variations of FAIs observed at Gadanki are compared in detail with those of Piura, which show a significant difference in the daytime observations. The observed difference has been discussed considering the factors governing the generation of FAIs.

  15. The Himalia Satellite Group: A Case Study on the Dynamical Self-spreading of Families of Irregular Satellites and Asteroids

    Science.gov (United States)

    Li, Daohai; Christou, Apostolos A.

    2015-11-01

    Many of the outer planets' irregular satellites are grouped into families, thought to originate from collisional fragmentation (Nesvorný et al 2004, AJ). Interestingly, families associated with the largest irregulars are either more dispersed than expected (e.g. J6 Himalia; Nesvorný et al 2003, AJ), or do not exist at all (e.g. S9 Phoebe; Ćuk et al 2003, DDA meeting #34). Christou (2005, Icarus) found that gravitational scattering by Himalia of its own group could explain the large velocity dispersion found by Nesvorný et al (2003, AJ). At the same time, Christou identified a new type of dynamical mechanism that intermittently locks the node of the satellite J10 Lysithea to that of Himalia. The same mechanism, but due to Ceres, was recently found to operate within the Hoffmeister family, dispersing its members and allowing an estimate of its age (Novaković et al 2015, ApJ).Here we revisit the issue of family self-dispersion, aiming to better understand it by studying its effects on the Himalia group. For this we utilise (a) intensive test particle simulations on a larger scale than those by Christou (2005, Icarus) (b) a semi-analytical treatment of the new resonance based on the secular theory of coorbital motion by Namouni (1999, Icarus). This has allowed us to obtain firmer constraints on the rate of dispersion over time and on how the resonance affects the long-term evolution of the orbital elements. A principal result of this work is that particles near the resonance evolve differently than those away from it. During the meeting, we will present a new estimate of the family’s age as well as an analysis of the resonant structure and how it affects Himalia family members. We will also discuss the broader implications for the long-term evolution of orbital concentrations of small bodies in the solar system.Astronomical research at the Armagh Observatory is funded by the Northern Ireland Department of Culture, Arts and Leisure (DCAL).

  16. Understanding PISA

    Directory of Open Access Journals (Sweden)

    Stephen DOWNES

    2005-04-01

    Full Text Available Understanding PISA Stephen DOWNESMoncton, CANADA ABSTRACT The headline was dramatic enough to cause a ripple in the reading public. "Students who use computers a lot at school have worse maths and reading performance," noted the BBC news article, citing a 2004 study by Ludger Woessmann and Thomas Fuchs (Fuchs and Woessman, 2004. It was not long before the blogosphere took notice. Taking the theme and running with it, Alice and Bill ask, "Computers Make School Kids Dumber?" They theorize, "If you track the admitted decline of education, you'll probably notice that it follows along with the increase of technology in the classroom." In a similar vein, James Bartholomew asks, "Do you think that the government will turn down the volume of its boasting about how it has spent billions introducing computers in schools (while keeping down the pay of teachers so much that there are shortages? Do you think it will stop sending governors of state schools glossy pamphlets about insisting that computers are used in their schools as much as possible?" In this study, therefore, PISA looks well beyond educational attainment, and also includes school demographics, such as whether it is a public or private school, has large or small classes, or has access or not to technological resources. Finally, it does measure student information-their family background, access to books and computers and parental support as well. The PISA survey departs from previous surveys in disregarding the stated curricula of the schools being measured. Therefore, the conclusion is not surprising, nor even wrong for him to consider independently of any parental or teacher support, considered without reference to the software running on it, considered without reference to student attitudes and interests, does not positively impact an education. Finally, he focus on missing the reporting of results

  17. Numerical Simulation of the Time Evolution of Small-Scale Irregularities in the F-Layer Ionospheric Plasma

    Directory of Open Access Journals (Sweden)

    O. V. Mingalev

    2011-01-01

    Full Text Available Dynamics of magnetic field-aligned small-scale irregularities in the electron concentration, existing in the F-layer ionospheric plasma, is investigated with the help of a mathematical model. The plasma is assumed to be a rarefied compound consisting of electrons and positive ions and being in a strong, external magnetic field. In the applied model, kinetic processes in the plasma are simulated by using the Vlasov-Poisson system of equations. The system of equations is numerically solved applying a macroparticle method. The time evolution of a plasma irregularity, having initial cross-section dimension commensurable with a Debye length, is simulated during the period sufficient for the irregularity to decay completely. The results of simulation indicate that the small-scale irregularity, created initially in the F-region ionosphere, decays accomplishing periodic damped vibrations, with the process being collisionless.

  18. irGPU.proton.Net: Irregular strong charge interaction networks of protonatable groups in protein molecules--a GPU solver using the fast multipole method and statistical thermodynamics.

    Science.gov (United States)

    Kantardjiev, Alexander A

    2015-04-05

    A cluster of strongly interacting ionization groups in protein molecules with irregular ionization behavior is suggestive for specific structure-function relationship. However, their computational treatment is unconventional (e.g., lack of convergence in naive self-consistent iterative algorithm). The stringent evaluation requires evaluation of Boltzmann averaged statistical mechanics sums and electrostatic energy estimation for each microstate. irGPU: Irregular strong interactions in proteins--a GPU solver is novel solution to a versatile problem in protein biophysics--atypical protonation behavior of coupled groups. The computational severity of the problem is alleviated by parallelization (via GPU kernels) which is applied for the electrostatic interaction evaluation (including explicit electrostatics via the fast multipole method) as well as statistical mechanics sums (partition function) estimation. Special attention is given to the ease of the service and encapsulation of theoretical details without sacrificing rigor of computational procedures. irGPU is not just a solution-in-principle but a promising practical application with potential to entice community into deeper understanding of principles governing biomolecule mechanisms. © 2015 Wiley Periodicals, Inc.

  19. Geomagnetic storm effects on the occurrences of ionospheric irregularities over the African equatorial/low-latitude region

    Science.gov (United States)

    Amaechi, P. O.; Oyeyemi, E. O.; Akala, A. O.

    2018-04-01

    The study investigated the effects of intense geomagnetic storms of 2015 on the occurrences of large scale ionospheric irregularities over the African equatorial/low-latitude region. Four major/intense geomagnetic storms of 2015 were analyzed for this study. These storms occurred on 17th March 2015 (-229 nT), 22nd June 2015 (-204 nT), 7th October 2015 (-124 nT), and 20th December 2015 (-170 nT). Total Electron Content (TEC) data obtained from five African Global Navigation Satellite Systems (GNSS) stations, grouped into eastern and western sectors were used to derive the ionospheric irregularities proxy indices, e.g., rate of change of TEC (ROT), ROT index (ROTI) and ROTI daily average (ROTIAVE). These indices were characterized alongside with the disturbance storm time (Dst), the Y component of the Interplanetary Electric Field (IEFy), polar cap (PC) index and the H component of the Earth's magnetic field from ground-based magnetometers. Irregularities manifested in the form of fluctuations in TEC. Prompt penetration of electric field (PPEF) and disturbance dynamo electric field (DDEF) modulated the behaviour of irregularities during the main and recovery phases of the geomagnetic storms. The effect of electric field over both sectors depends on the local time of southward turning of IMF Bz. Consequently, westward electric field inhibited irregularities during the main phase of March and October 2015 geomagnetic storms, while for the June 2015 storm, eastward electric field triggered weak irregularities over the eastern sector. The effect of electric field on irregularities during December 2015 storm was insignificant. During the recovery phase of the storms, westward DDEF suppressed irregularities.

  20. Magnetic storm effect on the occurrence of ionospheric irregularities at an equatorial station in the African sector

    Directory of Open Access Journals (Sweden)

    Olushola Abel Oladipo

    2014-01-01

    Full Text Available Large-scale ionospheric irregularities usually measured by GPS TEC fluctuation indices are regular occurrence at the equatorial region shortly after sunset around solar maximum. Magnetic storm can trigger or inhibit the generation of these irregularities depending on the local time the main phase of a particular storm occurs. We studied the effect of nine (9 distinct storms on the occurrence of ionospheric irregularities at Fraceville in Gabon (Lat = −1.63˚, Long = 13.55˚, dip lat. = −15.94˚, an equatorial station in the African sector. These storms occurred between November 2001 and September 2002. We used TEC fluctuation indices (i.e. ROTI and ROTIAVE estimated from 30 s interval Rinex data and also we used the storm indices (i.e. Dst, dDst/dt, and IMF BZ to predict the likely effect of each storm on the irregularities occurrence at this station. The results obtained showed that most of the storms studied inhibited ionospheric irregularities. Only one out of all the storms studied (i.e. September 4, 2002 storms with the main phase on the night of September 7-8 triggered post-midnight ionospheric irregularities. There are two of the storms during which ionospheric irregularities were observed. However, these may not be solely attributed to the storms event because the level of irregularities observed during these two storms is comparable to that observed during previous days before the storms. For this station and for the storms investigated, it seems like a little modification to the use of Aarons categories in terms of the local time the maximum negative Dst occurs could lead to a better prediction. However, it would require investigating many storms during different level of solar activities and at different latitudes to generalize this modification.

  1. Bone conducted vibration selectively activates irregular primary otolithic vestibular neurons in the guinea pig.

    Science.gov (United States)

    Curthoys, Ian S; Kim, Juno; McPhedran, Samara K; Camp, Aaron J

    2006-11-01

    The main objective of this study was to determine whether bone-conducted vibration (BCV) is equally effective in activating both semicircular canal and otolith afferents in the guinea pig or whether there is preferential activation of one of these classes of vestibular afferents. To answer this question a large number (346) of single primary vestibular neurons were recorded extracellularly in anesthetized guinea pigs and were identified by their location in the vestibular nerve and classed as regular or irregular on the basis of the variability of their spontaneous discharge. If a neuron responded to angular acceleration it was classed as a semicircular canal neuron, if it responded to maintained roll or pitch tilts it was classified as an otolith neuron. Each neuron was then tested by BCV stimuli-either clicks, continuous pure tones (200-1,500 Hz) or short tone bursts (500 Hz lasting 7 ms)-delivered by a B-71 clinical bone-conduction oscillator cemented to the guinea pig's skull. All stimulus intensities were referred to that animal's own auditory brainstem response (ABR) threshold to BCV clicks, and the maximum intensity used was within the animal's physiological range and was usually around 70 dB above BCV threshold. In addition two sensitive single axis linear accelerometers cemented to the skull gave absolute values of the stimulus acceleration in the rostro-caudal direction. The criterion for a neuron being classed as activated was an audible, stimulus-locked increase in firing rate (a 10% change was easily detectable) in response to the BCV stimulus. At the stimulus levels used in this study, semicircular canal neurons, both regular and irregular, were insensitive to BCV stimuli and very few responded: only nine of 189 semicircular canal neurons tested (4.7%) showed a detectable increase in firing in response to BCV stimuli up to the maximum 2 V peak-to-peak level we delivered to the B-71 oscillator (which produced a peak-to-peak skull acceleration of around

  2. Detection of increase in corneal irregularity due to pterygium using Fourier series harmonic analyses with multiple diameters.

    Science.gov (United States)

    Minami, Keiichiro; Miyata, Kazunori; Otani, Atsushi; Tokunaga, Tadatoshi; Tokuda, Shouta; Amano, Shiro

    2018-05-01

    To determine steep increase of corneal irregularity induced by advancement of pterygium. A total of 456 eyes from 456 consecutive patients with primary pterygia were examined for corneal topography and advancement of pterygium with respect to the corneal diameter. Corneal irregularity induced by the pterygium advancement was evaluated by Fourier harmonic analyses of the topographic data that were modified for a series of analysis diameters from 1 mm to 6 mm. Incidences of steep increases in the asymmetry or higher-order irregularity components (inflection points) were determined by using segmented regression analysis for each analysis diameter. The pterygium advancement ranged from 2% to 57%, with a mean of 22.0%. Both components showed steep increases from the inflection points. The inflection points in the higher-order irregularity component altered with the analysis diameter (14.0%-30.6%), while there was no alternation in the asymmetry components (35.5%-36.8%). For the former component, the values at the inflection points were obtained in a range of 0.16 to 0.25 D. The Fourier harmonic analyses for a series of analysis diameters revealed that the higher-order irregularity component increased with the pterygium advancement. The analysis results confirmed the precedence of corneal irregularity due to pterygium advancement.

  3. Menarche delay and menstrual irregularities persist in adolescents with type 1 diabetes

    Directory of Open Access Journals (Sweden)

    McFann Kim

    2011-05-01

    Full Text Available Abstract Background Menarche delay has been reported in adolescent females with type 1 diabetes (T1DM, perhaps due to poor glycemic control. We sought to compare age at menarche between adolescent females with T1DM and national data, and to identify factors associated with delayed menarche and menstrual irregularity in T1DM. Methods This was a cross-sectional study and females ages 12- 24 years (n = 228 with at least one menstrual period were recruited during their outpatient diabetes clinic appointment. The National Health and Nutrition Examination Survey (NHANES 2001-2006 data (n = 3690 for females 12-24 years were used as a control group. Results Age at menarche was later in adolescent females with T1DM diagnosed prior to menarche (12.81 +/- 0.09 years (mean+/- SE (n = 185 than for adolescent females diagnosed after menarche (12.17 0.19 years, p = 0.0015 (n = 43. Average age of menarche in NHANES was 12.27 +/- 0.038 years, which was significantly earlier than adolescent females with T1DM prior to menarche (p p = 0.77. Older age at menarche was negatively correlated with BMI z-score (r = -0.23 p = 0.0029 but not hemoglobin A1c (A1c at menarche (r = 0.01, p = 0.91. Among 181 adolescent females who were at least 2 years post menarche, 63 (35% reported usually or always irregular cycles. Conclusion Adolescent females with T1DM had a later onset of menarche than both adolescent females who developed T1DM after menarche and NHANES data. Menarche age was negatively associated with BMI z-score, but not A1c. Despite improved treatment in recent decades, menarche delay and high prevalence of menstrual irregularity is still observed among adolescent females with T1DM.

  4. Evaluation of head movement periodicity and irregularity during locomotion of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Ryuzo eShingai

    2013-03-01

    Full Text Available Caenorhabditis elegans is suitable for studying the nervous system, which controls behavior. C. elegans shows sinusoidal locomotion on an agar plate. The head moves not only sinusoidally but also more complexly, which reflects regulation of the head muscles by the nervous system. The head movement becomes more irregular with senescence. To date, the head movement complexity has not been quantitatively analyzed. We propose two simple methods for evaluation of the head movement regularity on an agar plate using image analysis. The methods calculate metrics that are a measure of how the head end movement is correlated with body movement. In the first method, the length along the trace of the head end on the agar plate between adjacent intersecting points of the head trace and the quasi-midline of the head trace, which was made by sliding an averaging window of 1/2 the body wavelength, was obtained. Histograms of the lengths showed periodic movement of the head and deviation from it. In the second method, the intersections between the trace of the head end and the trace of the 5 (near the pharynx or 50% (the mid-body point from the head end in the centerline length of the worm image were marked. The length of the head trace between adjacent intersections was measured, and a histogram of the lengths was produced. The histogram for the 5% point showed deviation of the head end movement from the movement near the pharynx. The histogram for the 50% point showed deviation of the head movement from the sinusoidal movement of the body center. Application of these methods to wild type and several mutant strains enabled evaluation of their head movement periodicity and irregularity, and revealed a difference in the age-dependence of head movement irregularity between the strains. A set of five parameters obtained from the histograms reliably identifies differences in head movement between strains.

  5. Nonlinear Passive Control of a Wave Energy Converter Subject to Constraints in Irregular Waves

    Directory of Open Access Journals (Sweden)

    Liguo Wang

    2015-06-01

    Full Text Available This paper investigates a passive control method of a point absorbing wave energy converter by considering the displacement and velocity constraints under irregular waves in the time domain. A linear generator is used as a power take-off unit, and the equivalent damping force is optimized to improve the power production of the wave energy converter. The results from nonlinear and linear passive control methods are compared, and indicate that the nonlinear passive control method leads to the excitation force in phase with the velocity of the converter that can significantly improve the energy production of the converter.

  6. A simple homogeneous model for regular and irregular metallic wire media samples

    Science.gov (United States)

    Kosulnikov, S. Y.; Mirmoosa, M. S.; Simovski, C. R.

    2018-02-01

    To simplify the solution of electromagnetic problems with wire media samples, it is reasonable to treat them as the samples of a homogeneous material without spatial dispersion. The account of spatial dispersion implies additional boundary conditions and makes the solution of boundary problems difficult especially if the sample is not an infinitely extended layer. Moreover, for a novel type of wire media - arrays of randomly tilted wires - a spatially dispersive model has not been developed. Here, we introduce a simplistic heuristic model of wire media samples shaped as bricks. Our model covers WM of both regularly and irregularly stretched wires.

  7. Methodology for evaluating pattern transfer completeness in inkjet printing with irregular edges

    Science.gov (United States)

    Huang, Bo-Cin; Chan, Hui-Ju; Hong, Jian-Wei; Lo, Cheng-Yao

    2016-06-01

    A methodology for quantifying and qualifying pattern transfer completeness in inkjet printing through examining both pattern dimensions and pattern contour deviations from reference design is proposed, which enables scientifically identifying and evaluating inkjet-printed lines, corners, circles, ellipses, and spirals with irregular edges of bulging, necking, and unpredictable distortions resulting from different process conditions. This methodology not only avoids differences in individual perceptions of ambiguous pattern distortions but also indicates the systematic effects of mechanical stresses applied in different directions to a polymer substrate, and is effective for both optical and electrical microscopy in direct and indirect lithography or lithography-free patterning.

  8. Methodology for evaluating pattern transfer completeness in inkjet printing with irregular edges

    International Nuclear Information System (INIS)

    Huang, Bo-Cin; Chan, Hui-Ju; Lo, Cheng-Yao; Hong, Jian-Wei

    2016-01-01

    A methodology for quantifying and qualifying pattern transfer completeness in inkjet printing through examining both pattern dimensions and pattern contour deviations from reference design is proposed, which enables scientifically identifying and evaluating inkjet-printed lines, corners, circles, ellipses, and spirals with irregular edges of bulging, necking, and unpredictable distortions resulting from different process conditions. This methodology not only avoids differences in individual perceptions of ambiguous pattern distortions but also indicates the systematic effects of mechanical stresses applied in different directions to a polymer substrate, and is effective for both optical and electrical microscopy in direct and indirect lithography or lithography-free patterning. (paper)

  9. A program to compute the area of an irregular polygon on a spheroidal surface

    Digital Repository Service at National Institute of Oceanography (India)

    Sivakholundu, K.M.; Prabaharan, N.

    (MATLAB). Short Note824 lar shapes. The analytical integrations were carried out with the software package MATLAB on a SUN workstation. The comparisons were made to check: 1. The eC128ect of varying strip width for integration. 2. Variation of accuracy... this program can be used to calculate the area on the spheroidal surface for irregular shapes without losing accuracy. REFERENCES Bomford, G. (1977) Geodesy. Oxford University Press, 731 pp. Larkin, B. J. (1988) A FORTRAN 77 program to calcu- late areas...

  10. HII regions in IC 1613: The ISM in a nearby dwarf irregular galaxy

    Science.gov (United States)

    Price, Jill S.; Mason, Stephen F.; Gullixson, Craig A.

    1990-01-01

    IC 1613, a nearby (725 kpc distant) dwarf irregular galaxy, has always been known to contain large, ring-shaped HII regions in its northeast corner. A new H alpha image has been obtained using the Bell Labs Charge Coupled Device (CCD) camera, an RCA 320 X 512 pixel-thinned, back-illuminated CCD, an H alpha filter of central wavelength 6562 A and width (full width half maximum) of 30 A, and the 42 inch telescope at Lowell Observatory. The low resolution images exhibit many new, faint features.

  11. Performance Comparisons of Improved Regular Repeat Accumulate (RA and Irregular Repeat Accumulate (IRA Turbo Decoding

    Directory of Open Access Journals (Sweden)

    Ahmed Abdulkadhim Hamad

    2017-08-01

    Full Text Available In this paper, different techniques are used to improve the turbo decoding of regular repeat accumulate (RA and irregular repeat accumulate (IRA codes. The adaptive scaling of a-posteriori information produced by Soft-output Viterbi decoder (SOVA is proposed. The encoded pilots are another scheme that applied for short length RA codes. This work also suggests a simple and a fast method to generate a random interleaver having a free 4 cycle Tanner graph. Progressive edge growth algorithm (PEG is also studied and simulated to create the Tanner graphs which have a great girth.

  12. Threshold Multi Split-Row algorithm for decoding irregular LDPC codes

    Directory of Open Access Journals (Sweden)

    Chakir Aqil

    2017-12-01

    Full Text Available In this work, we propose a new threshold multi split-row algorithm in order to improve the multi split-row algorithm for LDPC irregular codes decoding. We give a complete description of our algorithm as well as its advantages for the LDPC codes. The simulation results over an additive white gaussian channel show that an improvement in code error performance between 0.4 dB and 0.6 dB compared to the multi split-row algorithm.

  13. Photopolymerization of complex emulsions with irregular shapes fabricated by multiplex coaxial flow focusing

    Science.gov (United States)

    Wu, Qiang; Yang, Chaoyu; Yang, Jianxin; Huang, Fangsheng; Liu, Guangli; Zhu, Zhiqiang; Si, Ting; Xu, Ronald X.

    2018-02-01

    We fabricate complex emulsions with irregular shapes in the microscale by a simple but effective multiplex coaxial flow focusing process. A multiphase cone-jet structure is steadily formed, and the compound liquid jet eventually breaks up into Janus microdroplets due to the perturbations propagating along the jet interfaces. The microdroplet shapes can be exclusively controlled by interfacial tensions of adjacent phases. Crescent-moon-shaped microparticles and microcapsules with designated structural characteristics are further produced under ultraviolet light of photopolymerization after removing one hemisphere of the Janus microdroplets. These complex emulsions have potential applications in bioscience, food, functional materials, and controlled drug delivery.

  14. Bottomside sinusoidal irregularities in the equatorial F region. II - Cross-correlation and spectral analysis

    Science.gov (United States)

    Cragin, B. L.; Hanson, W. B.; Mcclure, J. P.; Valladares, C. E.

    1985-01-01

    Equatorial bottomside sinusoidal (BSS) irregularities have been studied by applying techniques of cross-correlation and spectral analysis to the Atmosphere Explorer data set. The phase of the cross-correlations of the plasma number density is discussed and the two drift velocity components observed using the retarding potential analyzer and ion drift meter on the satellite are discussed. Morphology is addressed, presenting the geographical distributions of the occurrence of BSS events for the equinoxes and solstices. Physical processes including the ion Larmor flux, interhemispheric plasma flows, and variations in the lower F region Pedersen conductivity are invoked to explain the findings.

  15. On H-irregularity strengths of G-amalgamation of graphs

    Directory of Open Access Journals (Sweden)

    Faraha Ashraf

    2017-10-01

    Full Text Available A simple graph G=(V(G,E(G admits an H-covering if every edge in E(G belongs at least to one subgraph of G isomorphic to a given graph H. Then the graph G admitting H-covering admits an H-irregular total k-labeling f: V(G U E(G \\to {1, 2, ..., k} if for every two different subgraphs H' and H'' isomorphic to H there is $wt_{f}(H' \

  16. Achievable capacity design for irregular and clustered high performance mesh networks

    CSIR Research Space (South Africa)

    Olwal, TO

    2012-11-01

    Full Text Available interference, it is assumed that no any two HPNs are placed within a radius less than 400 m at the edge and less than 700 m toward the centre of the deployment area. However, between any two HPNs the largest separation distance is allowed as much possible... q mc p bit-meters/sec when cm = O(n). Proof : Let us consider that in irregular and static networks, the node den- sity varies over space (i.e., an area) but stays constant over time. Suppose the regularity rate (probability) of HPN...

  17. A new Fortran 90 program to compute regular and irregular associated Legendre functions (new version announcement)

    Science.gov (United States)

    Schneider, Barry I.; Segura, Javier; Gil, Amparo; Guan, Xiaoxu; Bartschat, Klaus

    2018-04-01

    This is a revised and updated version of a modern Fortran 90 code to compute the regular Plm (x) and irregular Qlm (x) associated Legendre functions for all x ∈(- 1 , + 1) (on the cut) and | x | > 1 and integer degree (l) and order (m). The necessity to revise the code comes as a consequence of some comments of Prof. James Bremer of the UC//Davis Mathematics Department, who discovered that there were errors in the code for large integer degree and order for the normalized regular Legendre functions on the cut.

  18. Study of Railway Track Irregularity Standard Deviation Time Series Based on Data Mining and Linear Model

    Directory of Open Access Journals (Sweden)

    Jia Chaolong

    2013-01-01

    Full Text Available Good track geometry state ensures the safe operation of the railway passenger service and freight service. Railway transportation plays an important role in the Chinese economic and social development. This paper studies track irregularity standard deviation time series data and focuses on the characteristics and trend changes of track state by applying clustering analysis. Linear recursive model and linear-ARMA model based on wavelet decomposition reconstruction are proposed, and all they offer supports for the safe management of railway transportation.

  19. Structure of irregular galactic magnetic fields determined on the basis of cosmic ray measurements

    International Nuclear Information System (INIS)

    Somogyi, A.

    1975-02-01

    In the paper a method is described to determine the structural composition of random galactic fields on the basis of cosmic ray measurements, down to structures with characteristic length of the order of 0.001 to 1 pc. Assuming the diffusion mean free path of the particles to be independent of particle energy the spectral index of magnetic irregularities is estimated to be -(1.0+-0.5). The linear size of the confinement volume is found to be almost independent of particle energy. (Sz.Z.)

  20. Photographic investigation into the mechanism of combustion in irregular detonation waves

    Science.gov (United States)

    Kiyanda, C. B.; Higgins, A. J.

    2013-03-01

    Irregular detonations are supersonic combustion waves in which the inherent multi-dimensional structure is highly variable. In such waves, it is questionable whether auto-ignition induced by shock compression is the only combustion mechanism present. Through the use of high-speed schlieren and self-emitted light photography, the velocity of the different components of detonation waves in a {{ CH}}_4+2{ O}_2 mixture is analyzed. The observed burn-out of unreacted pockets is hypothesized to be due to turbulent combustion.